Metal complexes, manufacturing method thereof, flame-retardant polymer composition comprising the same and their use

The present invention relates to novel flame retardants and to manufacturing methods thereof, to flame-retardant polymer compositions, as well as to their uses.

Plastics usually need to be equipped with flame retardants in order to be able to meet the high flame-retardant requirements required by plastics processors and, in some cases, by the legislature. Preferably - also for ecological reasons - non- halogenated flame-retardant systems are used that form only small or no smoke gases.

9, 10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide or (6H-dibenz [c, e] [1, 2] oxa-phosphorine-6-oxide) (hereinafter also called „DOPO“) is an ester of phosphinic acid, wherein a phosphorous atom and an oxygen atom are incorporated into the base structure of a phenanthrene. DOPO has flame retardant properties and is a base compound for a variety of different halogen-free and very effective flame retardants for polymers.

DOPO may be synthesized by reaction of 2-phenylphenol with phosphorus trichloride in the presence of zinc chloride. The reaction product 6-chlorine (6H)-dibenz[c,e][1,2] oxaphosphorine (DOP-CI) is produced in high yields at high temperatures under hydrochlorine breakdown. When heating the DOP-CI at high temperatures in the presence of water DOPO is quantitatively produced in high purity.

DOPO is a white crystalline solid which is present in the form of two tautomers, 6/-/-dibenzo[c,e][1 ,2]oxaphosphorine-6-one (tautomer I) and 6-hydroxy-(6/-/)- dibenzo-[c,e][1 ,2]oxaphosphorin (tautomer II). This latter compound hydrolyses in the presence of water to 2'-hydroxydiphenyl-2-phosphinic acid.

In recent years, a number of DOPO derivatives have been synthesized, particularly for use in epoxy resins for electrical and electronic applications that are more hydrolysis stable and have significantly higher melting points. Summarizing, DOPO and and its derivatives are well known flame retardants in polymers, e.g. in polyesters. However, it has been shown that a variety of plastic materials are no longer processable in an acceptable fashion after the addition of DOPO (derivatives) due to conglutination of the processing equipment.

Metal salt based DOPO-derivatives can help overcoming these issues. Moreover, salts of diorganyl phosphinic acid, in particular their alkali metal and alkaline earth metal salts, and their use as flame retardant for polyesters and polyamides are known, e.g. from patents DE 2252258 and DE 2447727.

Mixtures of these salts with nitrogen bases, and their use as an effective flame retardant are described in WO 97/39053. US 4,208,321 describes (poly) metal phosphinates of the metals Cu, Fe, Sn, Co, W, Mn, Cr, V, Ti, Zn, Cd, and Mo. These compounds are used as flame-retardants for polyamides and polyesters. In all cases, these compounds comprise of salts of diorganyl phosphinic acid. Especially the use of mono organyl phosphinic acid salts, e.g. salts of phenyl phosphinic acid, which still have a P-H bond, are explicitly designated as disadvantageous. Such materials can be easily oxidized, therefore are unstable and lose their flame-retardant effect with time.

JP 2001-139586 A describes the use of zinc and aluminum salts of 10-hydroxy-9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide as flame-retardants for organic polymers. Both salts are synthesized by a double conversion starting from sodium phosphonate and metal chloride or metal sulfate.

The zinc salt is also prepared by reacting zinc acetate (hydrate) in ethanol with 10-hydroxy-9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, as described in JPS 53-127484 A.

DE 301 0375 describes the synthesis of zinc and aluminum salt of 10-hydroxy- 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide. This method is disadvantageous due to the high amount organic solvents required. Therefore, this process is not sustainable.

JP2003-306585 describes magnesium-bis-2-hydroxydiphenyl-2 'phosphinate and the Mg-salt of 10-hydroxy-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxid e as nucleating agents for polypropylene. Use as a flame retardant is not published.

JPH07-330963 describes the same salts as clarifiers for polypropylene. Use as a flame retardant is not published.

JPH04-252245 describes barium-bis (1'-hydroxy-2,2'-biphenylenephosphinate) in combination with inorganic fillers for use in polyolefins for improving the mechanical properties. A use as flame retardant is not published.

JPH03-223354 describes zinc bis (1'-hydroxy-2,2'-biphenylenephosphinate) in combination with inorganic fillers for improving mechanical properties in polyolefins. A use as flame retardant is not published.

EP 1657972 A1 describes a reaction product which is obtained by double conversion of DOPO with NaOH / water and ZnCl ₂ . The precipitation product thus obtained has the composition of zinc-bis-2-hydroxydiphenyl-2 phosphinate.

A homologous aluminum salt is also mentioned as an example in this document. The synthesis proceeds in anhydrous isopropanol as solvent by reacting aluminum alcoholate and DOPO. Both syntheses are therefore not sustainable.

DE 102010026973 A1 describes a flame-retardant combination which reduces the degradation reaction of plastics and the corrosion behavior during processing. This effect can be achieved by adding metal oxides or metal hydroxides.

It is also known that combinations of melamine polyphosphate and of metal phosphinates cause discoloration during processing in polyamide and polyester at higher temperatures due to partial polymer degradation (DE 102011 011 928). It is also known that pure DOPO exhibits only limited thermal stability (Phosphorus, Sulfur and Silicon, Vol. 139, 45-55).

Based on the above findings, a new class of compounds and manufacturing processes thereof were developed combining properties of known flame retardants in a way which can be considered as economically and ecologically suitable. Optimum would be an aqueous reaction medium thus avoiding handling of organic solvents.

Objective of the present invention is the provision of novel flame retardants which can be used alone or in combination with other flame-retardants in polymer compositions. These flame-retardants impart excellent flame-retardant properties to polymers without deteriorating their mechanical properties.

It has surprisingly been found that complexes comprising a selected metal and a combination of ligands based on DOPO, 10-hydroxy-group containing DOPO (also referred as DOPO-OH) or their thio analogues and hydroxide ions can be generated by reacting metal precursors on the DOPO or DOPO-OH sodium, potassium or lithium phosphinates (or their thio analogues) in combination with hydroxide ions and that these new structures can be used, alone or in combination with other additives as flame retardants.

DOPO or DOPO-OH or their thio analogues correspond to the formula (I) shown below wherein

Y represents 0 or S, and W represents hydrogen or OH. The present invention relates to metal complexes comprising a metal Me selected from the group consisting of Cu, Mg, Ca, Zn, Mn, Fe, Co, Ni, Ti, TiO, VO, Cr, WO2, MoO, Al, Sb, La, Zr, ZrO, Ce and/or Sn, a hydroxy group ligand and another ligand of formula (II), (III) or (IV) wherein Y represents 0 or S.

Preferred are metal complexes with structures of formulae (V), (VI) or (VII)

wherein Me is a metal selected from the group consisting of Cu, Mg, Ca, Zn, Mn, Fe, Co, Ni, Ti, TiO, VO, Cr, W0 ₂ , MoO, Al, Sb, La, Zr, ZrO, Ce and/or Sn, Y is 0 or S, preferably 0, x is 2, 3 or 4, preferably 2 or 3, a is 1 or 2, preferably 1 , b is a number with value a + x, and c is a number ³1 , preferably 1 -10 and most preferably 1 , with the proviso that in case the complex contains more than one Me-ions some of the Me-ions in the complex may contain no OH -ion ligands.

Preferably all Me-ions in a complex comprising several Me-ions contain at least one OH--ion ligand. The number of ligands in formulae (V), (VI) and (VII) is chosen in a way that the resulting complex is electroneutral, thus that the positive charge of Me is compensated by the negative charges of the ligands.

The metal ions Me included in the complexes of the present invention are preferably selected from the group consisting of independently from each other from Mg, Ca, Zn, Mn, Fe, Ti, TiO, Al, Ce or Sn, most perferably selected from the group consisting of Zn, TiO, Al and/or Ce.

A complex can contain one or more metal ions Me of the same metal or more metal ions Me from different metals. Preferably a complex contains one or more metal ions Me of the same metal.

Most preferably a complex contains one metal ions Me.

Preferred are complexes of formulae (V), (VI) and (VII), wherein Me is independently from one another selected from Cu, Mg, Ca, Zn, Mn, Fe, Co, Ni, TiO, ZrO, VO, Al, Sb, La, Ti, Zr, Ce or Sn. Furthermore, also two or more metals selected from Cu, Mg, Ca, Zn, Mn, Fe, Co, Ni, TiO, ZrO, VO, Al, Sb, La, Ti, Zr, Ce or Sn can be present in the complexes of formulae (V), (VI) and (VII) simultaneously and in all combinations.

More preferred are complexes of formulae (V), (VI) and (VII), wherein Me independently from one another are selected from Mg, Ca, Zn, Mn, Fe, Ti, TiO, Al, Ce or Sn. Furthermore, also two or more metals selected from Mg, Ca, Zn, Mn,

Fe, Ti, TiO, Al, Ce or Sn can be present in the ligands of formulae (V), (VI) and (VII) simultaneously and in all combinations.

The metal complexes comprising ligands derived from DOPO can either contain oxidized ligands, such as in complexes of formula (VII), and/or can contain hydrogenated ligands, such as in complexes of formula (V), and/or can contain hydrated ligands, such as in complexes of formula (VI). The oxidized species of ligands is in equilibrium with the corresponding hydrogen ated or hydrated species of ligands. Depending on the present conditions and the previous history (e.g. the production conditions), the equilibrium can be shifted towards the oxidized species or towards the hydrogenated or hydrated species. In extreme cases, even only the oxidized or hydrogenated or hydrated species might be present.

Preferred are metal complexes comprising besides hydroxy ions ligands of formulae (II) and (IV).

Also preferred are metal complexes comprising besides hydroxy ions ligands of formulae (III) and (IV).

Also preferred are metal complexes comprising besides hydroxy ions ligands of formula (IV). Preferably the complexes contain a combination of formulae (V) and (VII). The complexes of formula (VII) are in equilibrium with complexes of formula (V) and may be obtained by liberation of hydrogen from complexes of formula (V).

For complexes containing a combination of formulae (VI) and (VII) a similar effect can be observed. In this case complexes of formula (VII) are in equilibrium with complexes of formula (VI) and may be obtained by liberation of water from complexes of formula (VI).

Furthermore, the liberation of either hydrogen or water is possible for all combinations of complexes of the present invention comprising ligands of formulae (II) or (III), where the oxidized species of formula (IV) is in equilibrium with the hydrogenated or hydrated species of formula (II) or (III).

For the manufacture of the complexes of this invention, preferably of the compounds comprising formulae (V), (VI) and (VII), several processes are available.

In a first manufacturing method A two subsequent steps are performed. Method A, conversion A1 : DOPO and alkali metal hydroxide (KatOH), preferably sodium, potassium or lithium hydroxide, are reacted in an aqueous phase (see scheme 1). Optionally, alcohols can be added. DOPO and alkali hydroxide are applied in a molar ratio from 0.8 : 1 to 1 : 0.8, preferably 0.95 : 1 to 1 : 0.95 and most preferred in equimolar amounts.

Method A proceeds at temperatures below 100 °C, preferably from 20 °C to 90 °C, and most preferred from 30 °C to 70 °C, if normal pressure is applied. In case of higher pressures temperatures are applied at which liquid water is present in the reaction mixture.

In method A, conversion A1, DOPO reacts in a ring opening reaction with the added KatOH as depicted in scheme 1.

Method A therefore initially yields the alkali metal salt of DOPO conversion products (Kat-DOPO) as a solution as depicted in scheme 1.

Scheme 1 : Method A, Conversion A1

The product from method A, conversion A1 , is converted in a subsequent step, where two options are available by either using metal halides or metal sulfates.

EP 1657972 A1 quotes the Zn salt of DOPO as flame retardant, obtained from the conversion of DOPO with NaOH and ZnCl ₂ in water. In analogy, the synthesis can be performed in the present case, method A, conversion A2. For metal halides M ^x+ (X-) _x with X = F, Cl, Br and/or I and x = 2 or 3 a reaction stoichiometry as depicted in scheme 2 applies (method A, conversion A2) and the number of ligands is chosen in a way that the resulting complex is electroneutral.

Scheme 2: Method A, Conversion A2 (using metal halides): with x = a+b, a ³ 1 and c ³ 1.

Kat-DOPO and alkali hydroxide are preferably applied in conversion step A2 in a molar ratio from 0.8 : 1 to 1 : 0.8, preferably 0.95 : 1 to 1 : 0.95 and most preferred in equimolar amounts.

For metal sulfates, depending on the charge of the metal ion, following reaction stoichiometry applies as depicted in schemes 3 and 4 (method A, conversion A3 or A4): Scheme 3: method A, conversion A3 (using metal sulfates for M ²⁺ ):

with c ³ 1. Kat-DOPO and alkali hydroxide are preferably applied in conversion step A3 in a molar ratio from 0.8 : 1 to 1 : 0.8, preferably 0.95 : 1 to 1 : 0.95 and most preferred in equimolar amounts.

Scheme 4: Method A, Conversion A4 (using metal sulfates for M ³⁺ ): with a+b = 3, a ³ 1 and c ³ 1.

Kat-DOPO and alkali hydroxide are preferably applied in conversion step A4 in a molar ratio from 0.8 : 1 to 1 : 0.8, preferably 0.95 : 1 to 1 : 0.95 and most preferred in equimolar amounts.

The reactions depicted in schemes 1 , 2, 3 and 4 can be performed using DOPO- OH or all thio-analogues of DOPO and DOPO-OH instead of DOPO as a starting material. In all cases, the resulting precipitation products comprising the metal complexes of this invention, preferably the complexes of formulae (V), (VI) and/or (VII), are filtered off and washed with water.

Generally, also mixtures of the different metal halides or metal sulfates can be used in combination in one step. From this, mixed complexes can be obtained.

Remarkably, the use of sulfates exhibits technical advantages over the use of halides, namely an improvement of the precipitation. As a result, at comparable yields, smaller quantities of water are required to wash of the resulting salts and therefore low conductivity values can be reached faster than from the halides pathway. At the same time, waste water amounts can be reduced significantly.

Subsequently to the preparation method A, a granulation process can be used.

Preferred methods comprise spray driers, spray granulators (top spray, bottom spray, and counter current flow), fluidized bed granulators or paddle dryers. During this process, water remaining from method A can be removed unless a desired degree of residual moisture is reached. Granulation can be conducted by spray drying of an aqueous suspension of the reaction products from method A at higher temperatures, for example at 70 - 80 °C. Optionally, a spray granulation starting with a mixture of the educts (flow bed) and spraying of water on to the flow bed with subsequent drying step is feasible. The flow bed temperature is adjusted to elevated temperatures, for example to 70 - 80 °C, so granulate can be dried and a free-flowing non-dusting granulate is obtained. Residual moisture of this process is between 0,5 - 1 ,0 %. Alternatively, the obtained products can be dried in a static way either in vacuum or at ambient pressure at elevated temperatures, for example at 70 - 100 °C and then be used as is.

In a second manufacturing method B a metal complex containing besides metal Me and a hydroxy group a ligand of formula (II) or (III), preferably a complex of formula (V) or (VI), is treated in a calcination step taking place at elevated temperatures, preferably from 130 °C to 270 °C, more preferred at 170 °C to 220 °C, and most preferred between 180 °C and 200 °C. The calcination preferably takes place in vacuum or at ambient pressure. During this calcination step two possible reactions occur depending on the starting materials, metal complexes comprising ligands derived from DOPO or from DOPO-OH (or from their respective thio-analogues).

Scheme 5 shows the conversion of metal complexes comprising ligands derived from DOPO, meaning ligands of formula (II). Here hydrogen is liberated from the precipitation product of formula (VIII) and the resulting material is a cyclization product of formula (IX), given full conversion of starting material (VIII).

Scheme 5: Method B, Calcination of DOPO based starting materials of formula (VIII)

Scheme 6 shows the conversion of metal complexes comprising ligands derived from DOPO-OH, meaning ligands of formula (III). Here water is liberated from the precipitation product of formula (X) and the resulting material is a cyclization product of formula (XI), given full conversion of starting material (X).

Scheme 6: Method B, Calcination of DOPO-OH based starting materials of formula (X)

As can be easily seen, given a full conversion of the respective starting material, the product of formula (IX) is the same as the product of formula (XI).

The conversion steps shown in schemes 5 and 6 also hold true for all the thio- analogue derivatives of DOPO and DOPO-OH respectively.

Furthermore, water still remaining after drying in method A, can be released during calcination step of method B.

Preferably, calcination is carried out in a mixer or dryer, electric furnace, rotary furnace or high-speed mixer. Most preferably, a vertical or horizontal paddle mixer is used.

Special precaution must be taken in case of conversion of precipitation products of formula (VIII) into calcined products of formula (IX) as the liberation of significant amounts of hydrogen can cause over pressure, fire or explosions.

Products resulting from the calcination step can contain remaining starting material in any proportion without limiting the scope of the present invention.

Summarizing, the present invention relates to a first process for the preparation of complexes comprising Me, a hydroxy group and a ligand of formulae (II) or (III) said first process comprising the steps: i) reacting DOPO, DOPO-OH or a thio-analogue of DOPO or of DOPO-OH and an alkali metal hydroxide in an aqueous phase at temperatures above 20 °C to obtain an alkali metal salt of a ring-opened conversion product of DOPO, DOPO-OH or a thio-analogue of DOPO or of DOPO-OH, ii) adding a metal halide Me ^x+ (Hal-) _x and an aqueous solution of an alkali metal hydroxide to the product obtained from step i) and reacting this mixture at temperatures above 20 °C until a precipitate comprising the complex is formed, and iii) removing the liquid phase from the reaction mixture obtained in step ii) to obtain the complex comprising ME, the hydroxy group and the ligand of formulae (II) or (III).

In addition, the present invention relates to a second process for the preparation of complexes comprising ME, a hydroxy group and a ligand of formulae (II) or (III) said second process comprising the steps: i) reacting DOPO, DOPO-OH or a thio-analogue of DOPO or of DOPO-OH and an alkali metal hydroxide in an aqueous phase at temperatures above 20 °C to obtain an alkali metal salt of a ring-opened conversion product of DOPO, DOPO-OH or a thio-analogue of DOPO or of DOPO-OH, iia) adding a metal sulfate Me ²⁺ (S04 ^2- ) or (Me ³⁺ )2(S04 ^2- )3 and an aqueous solution of an alkali metal hydroxide to the product obtained from step i) and reacting this mixture at temperatures above 20 °C until a precipitate comprising the complex is formed, and iii) removing the liquid phase from the reaction mixture obtained in step ii) to obtain the complex comprising ME, the hydroxy group and the ligand of formulae (II) or (III).

Furthermore, the present invention relates to a third process for the preparation of complexes comprising ME, a hydroxy group and a ligand of formula (IV) said third process comprising the step: iv) calcinating a metal complex containing besides metal Me, a hydroxy group and a ligand of formula (II) or (III), preferably a complex of formula (V) or (VI), at temperatures from 130 °C to 270 °C in vacuum or at ambient pressure to result in a liberation of hydrogen or water.

The complexes of the present invention described above are particularly suitable as flame-retardants.

Surprisingly, a flame-retardant composition comprising selected components as described below show a synergistic performance in different plastic articles, e.g. a better compatibility, processability or flame-retardant performance than the single components of said composition.

The present invention thus relates to a flame-retardant polymer composition comprising: a) a polymer, b) a metal complex comprising a metal Me selected from the group consisting of Cu, Mg, Ca, Zn, Mn, Fe, Co, Ni, Ti, TiO, VO, Cr, W0 ₂ , MoO, Al, Sb, La, Zr, ZrO, Ce and/or Sn, a hydroxy group ligand and another ligand of formula (II), (III) or (IV) as defined above, and optionally c) a metal complex comprising a metal Me selected from the group consisting of Cu, Mg, Ca, Zn, Mn, Fe, Co, Ni, Ti, TiO, VO, Cr, W0 ₂ , MoO, Al, Sb, La, Zr, ZrO, Ce and/or Sn, and at least two ligands of formula (II), (III) or (IV) as defined above.

The amount of polymer a) in the flame-retardant polymer composition of the invention may vary in a broad range. Typically, the amount of component a) is 40 to 95 % by weight, preferably 50 to 90 % by weight and most preferred 60 to 85 % by weight, referring to the total amount of the polymer composition.

The amount of flame-retardant b) in the flame-retardant polymer composition of the invention may also vary in a broad range. Typically, the amount of component b) is 5 to 40 % by weight, preferably 7.5 to 30 % by weight and most preferred 10 to 25 % by weight, referring to the total amount of the polymer composition. The amount of flame-retardant c) in the flame-retardant polymer composition of the invention may also vary in a broad range. Typically, the amount of component c) is 1 to 25 % by weight, preferably 2 to 15 % by weight and most preferred 5 to 15 % by weight, referring to the total amount of the polymer composition.

The component ratio in the flame-retardant polymer composition comprising components a), b) and optionally c) may vary over a broad range. In one embodiment the flame-retardant polymer composition contains only one or more metal complexes of component b).

If besides component(s) b) additional component(s) c) are present, the weight ratio of component(s) b) to component(s) c) is preferably between 1 : 10 and 10: 1 , more preferred between 1: 1 and 1: 4.

Preferred metal complexes b) in the flame-retardant polymer compositions of this invention are metal complexes with structures of formulae (V), (VI) or (VII) defined above.

More preferred components b) in the flame-retardant compositions of this invention are metal complexes with structure of formula (VII) defined above in which Y = S.

Very preferred components b) are compounds of formula (VII) with Y = S.

Preferred component c) in the flame-retardant polymer compositions of this invention are compounds of formulae (XII), (XIII) and (XIV) wherein Me is a metal selected from the group consisting of Cu, Mg, Ca, Zn, Mn, Fe, Co, Ni, Ti, TiO, VO, Cr, W0 ₂ , MoO, Al, Sb, La, Zr, ZrO, Ce and/or Sn, Y is O or S, preferably O, x is 2, 3 or 4, preferably 2 or 3, d is a number with value x, and e is a number ³1 , preferably 1-10 and most preferably 1. Particularly preferred components c) are the following individual components: Mg(2'-hydroxy [1,1 '-biphenyl-2 -yl-2-phosphinate)2, CAS No. [165597-56-8], Zn(2'-hydroxy [1,1 '-biphenyl-2 -yl-2-phosphinate)2, CAS No. [139005-99-5], AI(2'-hydroxy[1 , 1 '-biphenyl-2 -yl-2-phosphinate) ₃ , CAS No. [145826-41-1] Ca(2'-hydroxy [1,1 '-biphenyl-2 yl-2-phosphinate) ₂ Mg(10-oxy-9, 10-dihydro-9-oxa-10-phosphaphenanthrene oxide ate)2,

CAS No. [147025-23-8],

Zn(10-oxy-9, 10-dihydro-9-oxa-10-phosphaphenanthrene oxide ate)2,

CAS No. [69151-14-0],

Al(10-oxy-9, 10-dihydro-9-oxa-10-phosphaphenanthrene oxide ate)3,

CAS No. [121 66-84-5],

Ca(10-oxy-9, 10-dihydro-9-oxa-10-phosphaphenanthrene oxide ate)2,

CAS No. [144722-45-2]

Preferably these compounds or mixtures of two or more thereof are included as component c) in the flame-retardant polymer compositions of the present invention.

Additional preferred components c) are Zn(10-oxy-9,10-dihydro-9-oxa- phosphaphenanthrene-10-sulfide-ate) ₂ , Al(10-oxy-9, 10-dihydro-9-oxa- phosphaphenanthrene-10-oxide-ate)3 and Zn(2'-hydroxy[1 , 1 ' -biphenyl-2 -yl-2- phosphinate)2.

Component a) of the flame-retardant polymer compositions of the invention can be any natural polymer including modifications by chemical treatment or any synthetic polymer. Polymer blends may also be used. Suitable polymers a) include thermoplastic polymers, thermoplastic elastomeric polymers, elastomers or duroplastic polymers.

Preferably thermoplastic polymers are used as component a). Preferred thermoplastic polymers are selected from the group consisting of polyamides, polycarbonates, polyolefins, polystyrenes, polyesters, polyvinyl chlorides, polyvinyl alcohols, ABS and polyurethanes. Moreover, duroplastic polymers may be used. These are preferably selected from the group consisting of epoxy resins, phenolic resins and melamine resins.

Additionally, also mixtures of two or more polymers, in particular thermoplastics and/or thermosets may be used.

Examples of polymers preferably used as component a) in the polymer compositions of the present invention are: polymers of monoolefins and diolefins, for example polypropylene, polyisobutylene, polybutene-1 , poly-4-methylpentene-1 , polyvinylcyclohexane, polyisoprene or polybutadiene and polymers of cycloolefins, for example of cyclopentene or norbornene, polyethylene (including crosslinked PE), e.g. high density polyethylene (HDPE) or high molecular weight PE (HDPE-HMW), high density polyethylene with ultra- high molecular weight (HDPE-UHMW), medium density polyethylene (MDPE), low density polyethylene (LDPE) and linear low density polyethylene (LLDPE), (VLDPE) and (ULDPE), as well as copolymers of ethylene and vinyl acetate (EVA); polystyrene, poly(p-methylstyrene), poly(alpha-methylstyrene); copolymers and graft copolymers of polybutadiene-styrene or polybutadiene and (meth)acrylonitrile, such as ABS and MBS; halogen-containing polymers, such as polychloroprene, polyvinyl chloride (PVC); polyvinylidene chloride (PVDC), copolymers of vinyl chloride / vinylidene chloride, vinyl chloride / vinyl acetate or vinyl chloride / vinyl acetate; poly(meth)acrylates, polymethyl methacrylates (PMMA), polyacrylamide, and polyacrylonitrile (PAN); polymers of unsaturated alcohols and amines or their acyl derivatives or acetals, such as polyvinyl alcohol (PVA), polyvinyl acetates, stearates, benzoates or maleates, polyvinylbutyrale, polyallylphthalate, and polyallylmelamine; homo- and copolymers of cyclic ethers, such as polyalkylene glycols, polyethylene oxides, polypropylene oxides and copolymers thereof with bisglycidyl ethers; polyacetals, such as polyoxymethylenes (POM) and polyurethane and acrylic modified polyacetales; polyphenylene oxides and sulfides and mixtures thereof with styrene polymers or polyamides; polyamides and copolyamides derived from diamines and dicarboxylic acids and/or from aminocarboxylic acids or the corresponding lactams, such as polyamide 4, polyamide 6, polyamide 6/6, 6/10, 6/9, 6/12, 12/12, polyamide 11, polyamide 12, aromatic polyamides derived from m-xylylenediamine and adipic acid and copolyamides modified with EPDM or ABS. Examples of preferred polyamides and copolyamides are those which are derived from e-caprolactam, adipic acid, sebacic acid, dodecanoic acid, isophthalic acid, terephthalic acid, hexamethylene diamine, tetramethylenediamine, 2-methyl-pentamethylene diamine, 2,2,4-trimethyl-hexamethylene diamine, 2,4,4-tri-methylhexamethylenediamine, m-xylylenediamine or bis(3-methyl- 4-aminocyclohexyl) methane; polyureas, polyimides, polyester imides, polyhydantoins and polybenzimidazoles; polyesters derived from dicarboxylic acids and dialcohols and/or from hydroxy-carboxylic acids or the corresponding lactones, such as polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, poly-1 , 4- dimethyl cyclohexane terephthalate, polyalkylene naphthalate (PAN) and polyhydroxybenzoates, polylactic acid esters and poly glycolic acid esters; polycarbonates and polyester carbonates; polyketones; mixtures and alloys of the above polymers, for example PP / EPDM, PA / EPDM or ABS, PVC / EVA, PVC / ABS, PBC / MBS, PC / ABS, PBTP /

ABS, PC / AS, PC / PBT, PVC / CPE, PVC / acrylic, POM / thermoplastic PUR, PC / thermoplastic PUR, POM / acrylate, POM / MBS, PPO / HIPS, PPO / PA 6.6 and copolymers, PA / HDPE, PA / PP, PA / PPO, PBT / PC /

ABS or PBT / PET / PC, and TPE-O, TPE-S and TPE-E; thermosets such as phenol-formaldehyde resins (PF), melamine- formaldeyhde resins (MF) or urea-formaldehyde-resins (UF) or mixtures thereof; epoxy resins ; phenolic resins; wood-plastic composites (WPC) and polymers based on PLA, PFIB and starch.

Preference is given to polyamides, polyesters, preferably to PET and PBT, polyurethanes, polycarbonates and epoxy resins.

Particularly preferred components a) are polyamided and polyesters and most preferred are glass fiber reinforced polyamides and polyesters.

The flame-retardant polymer composition of the present invention may contain further additives as component d).

The amount of component d) may vary in a broad range. Typical amounts of component d) are between 0 and 50 % by weight, preferably between 1 and 20 % by weight and more preferred between 5 and 15 % by weight, referring to the total amount of the flame-retardant polymer composition.

Examples of additives d) are antioxidants, light stabilizers, processing aids, nucleating agents and clarifiers, antistatic agents, lubricants, such as calcium stearate and zinc stearate, viscosity and impact modifiers, compatibilizers and dispersing agents, dyes or pigments, fillers and/or reinforcing agents.

The flame-retardant polymer composition of the present invention preferably contains additional fillers. These are are preferably selected from the group consisting of metal hydroxides and/or metal oxides, preferably alkaline earth metal, e.g. magnesium hydroxide, aluminum hydroxide, silicates, preferably phyllosilicates, such as bentonite, kaolinite, muscovite, pyrophyllite, marcasite and talc or other minerals, such as wollastonite, silica such as quartz, mica, feldspar and titanium dioxide, alkaline earth metal silicates and alkali metal silicates, carbonates, preferably calcium carbonate and talc, clay, mica, silica, calcium sulfate, barium sulfate, pyrite, glass beads, glass particles, wood flour, cellulose powder, carbon black, graphite and chalk.

The flame-retardant polymer composition of the present invention preferably contains reinforcing agents, more preferred reinforcing fibers. These are are preferably selected from the group consisting of glass fibers and carbon fibers. Fibers may be staple fibers or filaments, preferably staple fibers.

These additives d) can impart other desired properties to the polymer composition of the invention. In particular, the mechanical stability can be increased by reinforcement with fibers, preferably with glass fibers.

The flame-retardant polymer compositions of the invention are preferably prepared by providing the components a), b) and optionally c) and/or d), e.g. by mixing or by incorporation into a masterbatch, and by incorporating the components b) and optionally c) and/or d) into the polymer or polymer mixture.

The process for the production of flame-retardant polymer compositions is characterized by incorporating and homogenizing the flame retardant, component b) and optionally c), into polymer pellets (optionally together with other additives), in a compounding assembly at elevated temperatures. The resulting homogenized polymer melt is then formed into a strand, cooled and portioned. The resulting granules are dried, e.g. at 90 °C in a convection oven.

Preferably, the compounding equipment is selected from the group of single-screw extruders, multizone screws, or twin-screw extruders.

The invention also relates to the use of the above-defined metal complexes comprising a metal Me selected from the group consisting of Cu, Mg, Ca, Zn, Mn, Fe, Co, Ni, Ti, TiO, VO, Cr, WO2, MoO, Al, Sb, La, Zr, ZrO, Ce and/or Sn, a hydroxy group ligand and another ligand of formula (II), (III) or (IV) as a flame retardant.

Examples

The following examples serve to illustrate the invention.

Comparative Example 1 (in accordance with EP 1657972, Example 1)

Preparation of zinc bis-2-hydroxybiphenyl-2'-phosphinate (C24H20O6R2Zn) starting from ZnCl ₂ , and DOPO (C12H9O2P):

64.86 g (0.3 mol) 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) were suspended in 500 ml of water while stirring. Subsequently, 24.0 g (0.3 mol; 50% aqueous solution) NaOH were added to give a clear solution. Then, a solution of 20.40 g (0.15 mol) of zinc chloride dissolved in water was added dropwise. The solution became turbid from the starting precipitation of the product. Subsequently, the reaction mixture was stirred a further 2 h, the resulting white precipitate was filtered by suction, washed with water and dried to constant weight at 110 °C.

Yield: 75.75g (95.0% of theory) pH: 5,6 (10% suspension in distilled water, subsequent centrifugation; measured with a calibrated pH meter)

P(calc.): 11.65 % P(found): 11.60 %

Zn(calc.): 12.29 % Zn(found): 12.20 %

Conductivity: 2110 ms / cm (10% suspension in distilled water, following centrifugation; measured with a calibrated conductivity meter).

Examples for the synthesis via metal halide pathway: Example 2: Preparation of Zn(DOPO)(OH)

250.00 g (1.16 mol) DOPO were suspended in 2000 ml of water while stirring. Subsequently, 139.00 g (1.16 mol; 33% aq. solution) NaOH were added, to give a clear solution. Then, a solution of 161.00 g (1.16 mol) of zinc chloride dissolved in water was added dropwise. The solution became turbid. Subsequently, 139.00 g (1.16 mol, 33% aq. solution) NaOH were added. The reaction mixture was stirred for 1 h at 70 °C. After cooling to room temperature, the resulting white precipitate was filtered by suction, washed with water and dried to constant weight at 110 °C.

Yield: 300.67 g (82.30% of theory)

P(calc.): 8.82 % P(found): 9.80 %

Zn(calc.): 20.72 % Zn(found): 20.60 %

Conductivity: 510 ms / cm (10% suspension in distilled water, following centrifugation; measured with a calibrated conductivity meter).

Example 3: Preparation of Fe(DOPO)(OH)

250.00 g (1.16 mol) DOPO were suspended in 2000 ml of water while stirring. Subsequently, 139.00 g (1.16 mol; 33% aq. solution) NaOH were added, to give a clear solution. Then, a solution of 234.83 g (1.16 mol) of iron(ll) chloride tetrahydrate dissolved in 600 ml water was added dropwise. The solution became turbid. Subsequently, 139.00 g (1.16 mol, 33% aq. solution) NaOH were added. The reaction mixture was stirred for 1 h at 70 °C. After cooling to room temperature the resulting white precipitate was filtered by suction, washed with water and dried to constant weight at 110 °C.

Yield: 288.41 g (81.24 % of theory)

P(calc.): 10.12 % P(found): 10.00 %

Fe(calc.): 18.25 % Fe(found): 18.10 % Conductivity: 500 ms / cm (10% suspension in distilled water, following centrifugation; measured with a calibrated conductivity meter).

Example 4: Preparation of Fe(DOPO)2(OH)

250.00 g (1.16 mol) DOPO were suspended in 2000 ml of water while stirring. Subsequently, 139.00 g (1.16 mol; 33% aq. solution) NaOH were added, to give a clear solution. Then, a solution of 96.7 g (0.58 mol) of iron(lll) chloride dissolved in 600 ml water was added dropwise. The solution became turbid. Subsequently, 70.00 g (0.58 mol, 33% aq. solution) NaOH were added. The reaction mixture was stirred for 1 h at 70 °C. After cooling to room temperature, the resulting white precipitate was filtered by suction, washed with water and dried to constant weight at 110 °C.

Yield: 278.00 g (88.89 % of theory)

P(calc.): 11.49 % P(found): 11.40 %

Fe(calc.): 10.36 % Fe(found): 10.30 %

Conductivity: 505 ms / cm (10% suspension in distilled water, following centrifugation; measured with a calibrated conductivity meter).

Example 5: Preparation of Fe(DOPO)(OH)2

250.00 g (1.16 mol) DOPO were suspended in 2000 ml of water while stirring. Subsequently, 139.00 g (1.16 mol; 33% aq. solution) NaOH were added, to give a clear solution. Then, a solution of 193.4 g (1.16 mol) of iron(lll) chloride dissolved in 600 ml water was added dropwise. The solution became turbid. Subsequently, 278.00 g (2.31 mol, 33% aq. solution) NaOH were added. The reaction mixture was stirred for 1 h at 70 °C. After cooling to room temperature, the resulting white precipitate was filtered by suction, washed with water and dried to constant weight at 110 °C.

Yield: 334.93 g (89.38 % of theory) P(calc.): 9.59 % P(found): 9.50 %

Fe(calc.): 17.29 % Fe(found): 17.20 %

Conductivity: 517 ms / cm (10% suspension in distilled water, following centrifugation; measured with a calibrated conductivity meter).

Example 6: Preparation of Ca(DOPO)(OH)

100.04 g (0.46 mol) DOPO were suspended in 1000 ml of water while stirring. Subsequently, 55.59 g (0.46 mol; 33% aq. solution) NaOH were added, to give a clear solution. Then, a solution of 55.25 g (0.46 mol) of calcium chloride dissolved in 200 ml water was added dropwise. The solution became turbid. Subsequently, 55.59 g (0.46 mol, 33% aq. solution) NaOH were added. The reaction mixture was stirred for 1 h at 70 °C. After cooling to room temperature, the resulting white precipitate was filtered by suction, washed with water and dried to constant weight at 110 °C. High solubility of the final product limited the isolated yield.

Yield: 72.34 g (54.18 % of theory)

P(calc.): 10.67 % P(found): 10.50 %

Ca(calc.): 13.81 % Ca(found): 13.70 %

Conductivity: 670 ms / cm (10% suspension in distilled water, following centrifugation; measured with a calibrated conductivity meter).

Example 7: Preparation of Zn(DOPO-OH)(OH)

250.00 g (1.08 mol) 10-Flydroxy-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10- oxide (DOPO-OH) were suspended in 2000 ml of water while stirring. Subsequently, 130.50 g (1.08 mol; 33% aq. solution) NaOH were added, to give a clear solution. Then, a solution of 136.29 g (1.08 mol) of zinc chloride dissolved in 600 ml water was added dropwise. The solution became turbid. Subsequently, 130.50 g (1.08 mol, 33% aq. solution) NaOH were added. The reaction mixture was stirred for 1 h at 70 °C. After cooling to room temperature, the resulting white precipitate was filtered by suction, washed with water and dried to constant weight at 110 °C.

Yield: 271.25 g (75.75 % of theory)

P(calc.): 9.34 % P(found): 9.30 %

Zn(calc.): 19.72 % Zn(found): 19.70 %

Conductivity: 500 ms / cm (10% suspension in distilled water, following centrifugation; measured with a calibrated conductivity meter).

Example 8: Preparation of AI(DOPO-OH)2(OH)

250.00 g (1.08 mol) DOPO-OH were suspended in 2000 ml of water while stirring. Subsequently, 130.50 g (1.08 mol; 33% aq. solution) NaOH were added, to give a clear solution. Then, a solution of 243.90 g (0.54 mol) of aluminum chloride hexahydrate dissolved in 200 ml water was added dropwise. The solution became turbid. Subsequently, 130.50 g (1.08 mol, 33% aq. solution) NaOH were added. The reaction mixture was stirred for 1 h at 70 °C. After cooling to room temperature, the resulting white precipitate was filtered by suction, washed with water and dried to constant weight at 110 °C.

Yield: 247.51 g (84.51 % of theory)

P(calc.): 11.42 % P(found): 11.30 %

Al(calc.): 4.97 % Al(found): 5.00 %

Conductivity: 514 ms / cm (10% suspension in distilled water, following centrifugation; measured with a calibrated conductivity meter).

Example 9: Preparation of AI(DOPO-OH)(OH)2

250.00 g (1.08 mol) DOPO-OH were suspended in 2000 ml of water while stirring. Subsequently, 130.50 g (1.08 mol; 33% aq. solution) NaOH were added, to give a clear solution. Then, a solution of 260.74 g (1.08 mol) of aluminum chloride hexahydrate dissolved in 200 ml water was added dropwise. The solution became turbid. Subsequently, 261.00 g (2.16 mol, 33% aq. solution) NaOH were added. The reaction mixture was stirred for 1 h at 70 °C. After cooling to room temperature, the resulting white precipitate was filtered by suction, washed with water and dried to constant weight at 110 °C.

Yield: 265.87 g (79.37 % of theory)

P(calc.): 9.99 % P(found): 10.00 %

Al(calc.): 8.70 % Al(found): 8.60 %

Conductivity: 508 ms / cm (10% suspension in distilled water, following centrifugation; measured with a calibrated conductivity meter).

Example 10: Preparation of Fe(DOPO-OH)(OH)

250.00 g (1.08 mol) DOPO-OH were suspended in 2000 ml of water while stirring. Subsequently, 130.50 g (1.08 mol; 33% aq. solution) NaOH were added, to give a clear solution. Then, a solution of 218.40 g (1.08 mol) of iron (II) chloride tetrahydrate dissolved in 300 ml water was added dropwise. The solution became turbid. Subsequently, 130.50 g (1.08 mol, 33% aq. solution) NaOH were added. The reaction mixture was stirred for 1 h at 70 °C. After cooling to room temperature, the resulting white precipitate was filtered by suction, washed with water and dried to constant weight at 110 °C.

Yield: 275.58 g (79.24 % of theory)

P(calc.): 9.62 % P(found): 9.50 %

Fe(calc.): 17.34 % Ca(found): 17.20 %

Conductivity: 521 ms / cm (10% suspension in distilled water, following centrifugation; measured with a calibrated conductivity meter). Example 11: Preparation of Fe(DOPO-OH)2(OH)

250.00 g (1.08 mol) DOPO-OH were suspended in 2000 ml of water while stirring. Subsequently, 130.50 g (1.08 mol; 33% aq. solution) NaOH were added, to give a clear solution. Then, a solution of 90.03 g (0,54 mol) of iron(lll) chloride dissolved in 200 ml water was added dropwise. The solution became turbid. Subsequently, 65.26 g (0.54 mol, 33% aq. solution) NaOH were added. The reaction mixture was stirred for 1 h at 70 °C. After cooling to room temperature, the resulting beige precipitate was filtered by suction, washed with water and dried to constant weight at 110 °C.

Yield: 278.00 g (90.13 % of theory)

P(calc.): 10.84 % P(found): 10.70 %

Fe(calc.): 9.78 % Fe(found): 9.70 %

Conductivity: 510 ms / cm (10% suspension in distilled water, following centrifugation; measured with a calibrated conductivity meter).

Example 12: Preparation of Fe(DOPO-OH)(OH)2

250.00 g (1.08 mol) DOPO-OH) were suspended in 2000 ml of water while stirring. Subsequently, 130.50 g (1.08 mol; 33% aq. solution) NaOH were added, to give a clear solution. Then, a solution of 174.53 g (1.08 mol) of iron(lll) chloride dissolved in 600 ml water was added dropwise. The solution became turbid. Subsequently, 260.80 g (2.16 mol, 33% aq. solution) NaOH were added. The reaction mixture was stirred for 1 h at 70 °C. After cooling to room temperature, the resulting white precipitate was filtered by suction, washed with water and dried to constant weight at 110 °C.

Yield: 296.00 g (80.84 % of theory)

P(calc.): 9.14 % P(found): 9.10 %

Fe(calc.): 16.47 % Fe(found): 16.40 % Conductivity: 518 ms / cm (10% suspension in distilled water, following centrifugation; measured with a calibrated conductivity meter).

Examples for the synthesis via metal sulfate pathway:

Example 13: Preparation of Zn(DOPO)(OH)

250.00 g (1.16 mol) DOPO were suspended in 2000 ml of water while stirring. Subsequently, 139.00 g (1.16 mol; 33% aq. solution) NaOH were added, to give a clear solution. Then, a solution of 333.57 g (1.16 mol) of zinc sulfate heptahydrate dissolved in water was added dropwise. The solution became turbid.

Subsequently, 139.00 g (1.16 mol, 33% aq. solution) NaOH were added. The reaction mixture was stirred for 1 h at 70 °C. After cooling to room temperature, the resulting precipitate was filtered by suction, washed with water and dried to constant weight at 110 °C.

Yield: 312.76 g (85.44 % of theory)

P(calc.): 9.82 % P(found): 9.80 %

Zn(calc.): 20.72 % Zn(found): 20.60 %

Conductivity: 353 ms / cm (10% suspension in distilled water, following centrifugation; measured with a calibrated conductivity meter).

Example 14: Preparation of Fe(DOPO)2(OH)

20.00 g (0.0925 mol) DOPO were suspended in 60 ml of water while stirring. Subsequently, 11.10 g (0.0925 mol; 33% aq. solution) NaOH were added, to give a clear solution. Then, a solution of 12.01 g (0.0231 mol) of iron(lll) sulfate hydrate dissolved in water was added dropwise. The solution became turbid.

Subsequently, 5.55 g (0.0463 mol, 33% aq. solution) NaOH were added. The reaction mixture was stirred for 1 h at 70 °C. After cooling to room temperature, the resulting precipitate was filtered by suction, washed with water and dried to constant weight at 110 °C. Yield: 22.7 g (92.21 % of theory)

P(calc.): 11.49 % P(found): 11.40 %

Fe(calc.): 10.36 % Fe(found): 10.30 %

Conductivity: 319 ms / cm (10% suspension in distilled water, following centrifugation; measured with a calibrated conductivity meter).

Example 15: Preparation of Fe(DOPO-OH)2(OH)

21.48 g (0.0925 mol) DOPO-OH were suspended in 100 ml of water while stirring. Subsequently, 11.10 g (0.0925 mol; 33% aq. solution) NaOH were added, to give a clear solution. Then, a solution of 12.01 g (0.0231 mol) of iron(lll) sulfate hydrate dissolved in water was added dropwise. The solution became turbid.

Subsequently, 5.55 g (0.0463 mol, 33% aq. solution) NaOH were added. The reaction mixture was stirred for 1 h at 70 °C. After cooling to room temperature, the resulting precipitate was filtered by suction, washed with water and dried to constant weight at 110 °C.

Yield: 24.06 g (91.21 % of theory)

P(calc.): 10.84 % P(found): 10.70 %

Fe(calc.): 9.78 % Fe(found): 9.70 %

Conductivity: 300 ms / cm (10% suspension in distilled water, following centrifugation; measured with a calibrated conductivity meter).

Example 16: Preparation of Fe(DOPO-OH)(OH)

10.00 g (0.043 mol) DOPO-OH were suspended in 200 ml of water while stirring. Subsequently, 5.17 g (0.043 mol; 33% aq. solution) NaOH were added, to give a clear solution. Then, a solution of 11.97 g (0.043 mol) of iron(ll) sulfate heptahydrate dissolved in water was added dropwise. The solution became turbid. Subsequently, 5.17 g (0.043 mol, 33% aq. solution) NaOH were added. The reaction mixture was stirred for 1 h at 70 °C. After cooling to room temperature, the resulting precipitate was filtered by suction, washed with water and dried to constant weight at 110 °C.

Yield: 11.37 g (82.09 % of theory)

P(calc.): 9.62 % P(found): 9.60 %

Fe(calc.): 17.34 % Fe(found): 17.30 %

Conductivity: 470 ms / cm (10% suspension in distilled water, following centrifugation; measured with a calibrated conductivity meter).

Example 17: Preparation of Zn(DOPO-OH)(OH)

10.00 g (0.043 mol) DOPO-OH were suspended in 200 ml of water while stirring. Subsequently, 5.17 g (0.043 mol; 33% aq. solution) NaOH were added, to give a clear solution. Then, a solution of 12.39 g (0.043 mol) of zinc sulfate heptahydrate dissolved in 100 ml water was added dropwise. The solution became turbid. Subsequently, 5.17 g (0.043 mol, 33% aq. solution) NaOH were added. The reaction mixture was stirred for 1 h at 70 °C. After cooling to room temperature, the resulting precipitate was filtered by suction, washed with water and dried to constant weight at 110 °C.

Yield: 12.76 g (89.48 % of theory)

P(calc.): 9.34 % P(found): 9.30 %

Zn(calc.): 19.72 % Zn(found): 19.60 %

Conductivity: 344 ms / cm (10% suspension in distilled water, following centrifugation; measured with a calibrated conductivity meter).

Example 18: Preparation of AI(DOPO-OH)2(OH)

10.00 g (0.043 mol) DOPO-OH were suspended in 200 ml of water while stirring. Subsequently, 5.17 g (0.043 mol; 33% aq. solution) NaOH were added, to give a clear solution. Then, a solution of 7.18 g (0.0108 mol) of aluminum sulfate octadecahydrate dissolved in 100 ml water was added dropwise. The solution became turbid. Subsequently, 2.59 g (0.0215 mol, 33% aq. solution) NaOH were added. The reaction mixture was stirred for 1 h at 70 °C. After cooling to room temperature, the resulting precipitate was filtered by suction, washed with water and dried to constant weight at 110 °C.

Yield: 9.97 g (85.05 % of theory)

P(calc.): 11.42 % P(found): 11.30 % Al(calc.): 4.97 % Al(found): 5.00 %

Conductivity: 320 ms / cm (10% suspension in distilled water, following centrifugation; measured with a calibrated conductivity meter). In analogy to these examples, also other compounds according to the present invention can be prepared.

Comparison of halide vs. sulfate pathway

The products obtained were analyzed by thermogravimetric analysis (TGA and DSC). The TGA results are summarized in Tab. 1.

Tab. 1: Thermogravimetric Analysis: weight loss

Data from Tab. 1 confirms the usability of all compounds as a flame retardant.

To demonstrate the performance as flame retardant, new flame retardants selected from Tab. 1 were tested in polyamide 66 according these conditions:

A mixture of 45% by weight of Ultramid® A27 E (BASF, polyamide 66), 12.5% by weight of synthesized flame retardant (see examples), 12.5% by weight of Melapur 200 (BASF, melamine polyphosphate) and 30% by weight. % Glass fibers (PPG Fiber Glass, HP3610 EC104,5 mm) are compounded on a microcompounder

(type X-Plore) at temperatures of 280 to 300 °C to a polymer molding composition. The homogenized polymer strand is placed directly in a cylinder, then processed on an injection molding unit (type X-Plore) at 235 to 250 °C to form a normalized polymer molding with a thickness of 1.6 mm (mold temperature about 90 °C). The flame-retardant tests were performed in accordance with UL-94 test methods. The results are summarized in Table 2. Table 2: Flammability test

The results of the flammability test according to UL-94 test methods confirm the suitability of the substances as flame retardants