EP4028467A1

EP4028467A1 - Flame-retardant composition, polymer molding composition comprising same and use thereof

Info

Publication number: EP4028467A1
Application number: EP20767550.5A
Authority: EP
Inventors: Stefan Hauck; Elke Schlosser
Original assignee: Clariant International Ltd
Current assignee: Clariant International Ltd
Priority date: 2019-09-11
Filing date: 2020-09-08
Publication date: 2022-07-20
Also published as: CN114364729B; CN114364729A; WO2021048155A1

Abstract

Flame-retardant composition, polymer molding composition comprising same and use thereof Disclosed are compositions comprising a) a phosphinate, and 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, WO2, MoO, Al, Sb, La, Zr, ZrO, Ce and/or Sn, a hydroxy group ligand and another ligand of formula 10 (II), (III) or (IV) wherein Y represents O or S. The composiitons can be used as flame-retardants in polymer compositions which exhibit reduced wear to processing equipment and show improved flowability.

Description

Flame-retardant composition, polymer molding composition comprising same and use thereof

The present invention relates to a novel flame-retardant composition and to improved non-corrosive and readily flowable polymer molding compositions which can be used to make shaped articles with improved flame-retardancy.

Salts of phosphinic acids (phosphinates) have proven to be effective flame- retardant additives for thermoplastic polymers (DE-A-2252258 and

DE A 2447727). Calcium and aluminum phosphinates have been described as particularly effective in polyesters and affect the material properties of the polymer molding compositions less than, for example, the alkali metal salts

(EP A 0699708).

DE-A-19607635 describes calcium and aluminum phosphinates as particularly effective flame retardants for polyamides. Polyamides are polymers which contain recurring units in the polymer chain via an amide group. Particularly suitable polyamides are called polyamide 6 and polyamide 66. The resulting molding compounds achieve UL 94 fire classification V-0 with a test specimen thickness of 1.2 mm.

In addition, synergistic combinations of phosphinates with various nitrogen- containing compounds have been found to be more effective than flame retardants in a whole range of polymers as the phosphinates alone (WO 1997/039053,

DE-A-19734437, DE-A-19737727 and US 6,255,371 B1 ).

Among other things, melamine and melamine compounds have been described as effective synergists, for example melamine cyanurate and melamine phosphate, which themselves also have a certain flame retardancy in certain thermoplastics but are significantly more effective in combination with phosphinates.

Also higher molecular weight derivatives of melamine as the condensation products melam, melem and melon and corresponding reaction products of these compounds with phosphoric acid such as dimelamine pyrophosphate and melamine polyphos-phates have been described as flame retardants and effective as synergists to phosphinates.

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, 6H-dibenzo[c,e][1 ,2]oxaphosphorine-6-one (tautomer I) and 6-hydroxy-(6H)- 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-oxide 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 ZnCI₂. 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.

A disadvantage of the phospinates is a greater wear of metal parts of the plasticizing unit, e.g. an extruder, and the nozzle when compounding or injection molding of polymers, e.g. of polyesters or of polyamides with certain phosphinates.

In general, hard fillers (such as glass fibers) together with corrosive fission products (such as flame retardants) lead to wear on metal surfaces of tools. Depending on the material quality of the metallic surfaces and the plastics used, this necessitates frequent replacement of the heating jacket of the conveyor unit, of the conveyor screw and of the injection molding tools. Since glass-fiber- reinforced thermoplastic polymers are abrasive, the possibilities of corrosion protection of the screws are limited since very corrosion-resistant steels do not have the required hardness for the processing of glass fiber-reinforced polymers.

According to DIN EN ISO 8044, corrosion is the physico-chemical interaction between a metal and its surroundings. As a result, there may be a change in the properties of the metal, which can cause a significant deterioration in the function of the metal, the environment or the technical system of which it forms part.

It has now surprisingly been found that mixtures of phosphinates with selected metal complexes comprising 9,10-Dihydro-9-oxa-10-phosphaphenanthrene-10- oxide or (6H-dibenz [c, e] [1 , 2] oxa-phosphorine-6-oxide) ligands (hereinafter also called „DOPO“)and additional OH ligands significantly reduce wear in polymer molding compositions and improve the flowability of such compositions. The combination is an effective flame retardant and in parallel significantly lower material wear and higher flowabilities can be achieved when using the phosphinates of the metals alone. It was also surprisingly found that the high heat resistance of the polymers, especially of polyamides, is largely retained and that the flame-retarded polymer mixtures can be processed at high temperatures, without causing polymer degradation or discoloration.

Because of their dimensional stability at high temperatures and the favorable fire behavior, these polymers, in particular the high temperature polyamides are very well suited for the production of thin-walled moldings for the electrical and electronics industry.

Objective of the invention was to provide a flame-retardant which attributes excellent flame-retardancy to a polymer composition and which results in markedly reduced wear of the equipment and of increased flowability during processing of the molding composition.

It has surprisingly been found that mixtures comprising phosphinates and 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 used as a flame-retardant for polymers which exhibit, besides an excellent flame-retardancy and an improved flowability, a drastically reduced wear at the metal parts of the processing equipment .

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 a composition comprising a) a phosphinate, preferably a phosphinate of formula (XV), wherein

R¹ and R² independently of one another are the same or different and are alkyl and/or aryl, preferably C₁-C₆-alkyl and/or phenyl,

M is a metal selected from Cu, Ca, Mg, Zn, Mn, Fe, Al, Co, Ni, Sn, Zr, ZrO, Ce, MoO, WO2, VO, La, Ti, TiO or Sb, preferably selected from Zn, Al, Fe or TiO, m is an integer from 1 to 3, and n is a number with value 1/m, and 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, 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.

Hereinafter, the term "phosphinic acid salt" or “phosphinate” includes salts of phosphinic and diphosphinic acids and their polymers.

The phosphinic acid salts prepared in aqueous medium are essentially monomeric compounds. Depending on the reaction conditions, polymeric phosphinic salts may also be formed under certain circumstances.

Suitable phosphinic acids as a constituent of the phosphinic acid salts are, for example:

Dimethylphosphinic acid, ethyl-methylphosphinic acid, diethylphosphinic acid, methyl-n-propyl-phosphinic acid, dipropylphosphinic acid, ethyl-butylphosphinic acid, dibutylphosphinic acid, ethyl-hexylphosphinic acid, butyl-hexylphosphinic acid, methyl-phenyl-phosphinic acid and diphenylphosphinic acid.

The phosphinic acid salts used as component a) in the composition of the present invention can be prepared by known methods, as described in more detail, for example, in EP-A-0699708. Phosphinic acids are reacted, for example, in aqueous solution with metal carbonates, metal hydroxides or metal oxides.

The aforementioned phosphinic acid salts can be used in varous physical form for the flame-retardant combination of the invention depending on the type of polymer used and the desired properties. Thus, for example, the phosphinic acid salts can be ground to a finely divided form to achieve a better dispersion in the polymer. The phosphinic salts, as used in the flame-retardant combination according to the invention, are thermally stable, neither decompose the polymers during processing nor do they influence the production process of the plastic molding compound. The phosphinic acid salts are non-volatile under the usual thermoplastic polymer manufacturing and processing conditions.

Preferred components a) are phosphinic acid salts of formula (XV), wherein R¹, R² are identical or different and are methyl, ethyl, n-propyl, isopropyl, n-butyl, tert- butyl, n-pentyl and/or phenyl.

Preferred phosphinates, component a), are compounds of formula (XV), wherein R¹ and R² each are C₁-C₆-alkyl, preferably methyl, ethyl, propyl or butyl, and wherein M is Zn, Fe, TiO or Al, preferably Al.

Preferred metal complexes, component b), are those 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, WO₂, 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, component b) of the present invention, are preferably selected from the group consisting of independent from each other from Mg, Ca, Zn, Mn, Fe, Ti, TiO, Al, Sn and/or Ce, most preferably selected from the group consisting of Zn, TiO, Al, Sn 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 components b) are complexes of formulae (V), (VI) and (VII), wherein Me is independently from one another selected from Mg, Ca, Zn, Mn, Fe, Ti, TiO, Al, Sn or Ce. Furthermore, also two or more metals selected from Mg, Ca, Zn, Mn, Fe, Ti, TiO, Al, Sn or Ce can be present in the complexes of formulae (V), (VI) and (VII) simultaneously and in all combinations.

More preferred components b) are complexes of formulae (V), (VI) and (VII), wherein Me independently from one another are selected from Zn, TiO, Al, Sn or Ce. Furthermore, also two or more metals selected from Zn, TiO, Al, Sn and/or Ce 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 components b) are metal complexes comprising besides hydroxy ions ligands of formulae (II) and (IV).

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

Preferably components b) are used, wherein 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).

Component a) is typically present in 50 - 99.5 % by weight and component b) is typically present in 0.5 - 50 % by weight in the flame-retardant mixture of this invention. Preferably, component a) is contained in 60 - 70 % by weight and component b) is contained in 30 - 40 % by weight in the flame-retardant mixture. These percentages refer to the total amount of flame-retardant mixture.

The phospinates corresponding to component a) of the composition of this invention are known compounds and can be manufactured by known processes.

For the manufacture of the complexes corresponding to component b) of the composition 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 stems 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 ZnCI₂ 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 M²⁺): 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 M³⁺): 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.

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)

(VIII) (IX)

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)

(X) (XI)

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 stems 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.

In the flame-retardant composition comprising components a) and b) preferably a nitrogen compound, phosphorus compound or phosphorus nitrogen compound is introduced as further component c).

Component c) is typically present in 0 - 70 % by weight, preferably in 10 - 50 % by weight, in the flame-retardant mixture of this invention. These percentages refer to the total amount of flame-retardant mixture.

Preferred components c) are melamine phosphate, dimelamine phosphate, melamine pyrophosphate, melamine polyphosphates, melampolyphosphates, melem polyphosphates and/or melon polyphosphates and/or melamine condensation products such as melam, melem and/or melon.

Further preferred components c) are oligomeric esters of tris-(hydroxyethyl) isocyanurate with aromatic polycarboxylic acids, benzoguanamine, tris- (hydroxyethyl) isocyanurate, allantoin, glycouril, melamine, melamine cyanurate, dicyandiamide, guanidine and/or carbodiimides.

Still further preferred components c) are selected from the group of metal phosphate or metal pyrophosphate. Additional preferred components c) are melamine-metal phosphates and metal phosphate azines, e.g. bis-melamine-zinc diphosphate (M2ZP2), bis-melamine Magnesium diphosphate or bis-melamine aluminum triphosphate (M₂AP₃).

Metal pyrophosphates are preferred examples of metal phosphates. In particular, aluminum and zinc pyrophosphate, zinc and aluminum triphosphate, aluminum and zinc metaphosphate, aluminum and zinc orthophosphate, or mixtures thereof are preferred.

From the class of hypophosphites, salts containing Mg, Ca, Zn and Al salt are particularly preferred.

Additional preferred components c) comprise red phosphorus, oligomeric phosphate esters, oligomeric phosphonate esters, cyclic phosphonate esters, thio pyrophosphoric acid esters, melamine orthophosphate or melamine pyrophosphate, melamine diphosphate, melamine polyphosphate, melam (polyphosphate), and melem as well as diguanidin phosphate, melamine phenylphosphinate, monomeric, oligomeric and polymeric melamine phenylphosphonate, ammonium polyphosphate, melamine phenylphosphonate and its half ester salt, as described in WO 2010/063623. Furthermore, melamine benzenephosphinate, as described in WO2010/057851, hydroxyalkyl phosphinoxide, as described in WO 2009/034023, tetrakis hydroxymethyl phosphonium and - phospholane (oxide) - or phosphole derivatives and bisphosphor amidate with piperazine as a bridge member or a phosphinate, the substance class of NOR FIALS compounds (N-alkoxyamine based hindered amine light stabilizer, e.g. Flamestab NOR 116 by BASF or Flostavin NOW by Clariant), and mixtures thereof.

Additionally, preferred components c) are aminouracils, tris-hydroxyethyl isocyanu- rate, melamine cyanurate, or mixtures thereof.

Furthermore, also tris-hydroxyethyl-isocyanurate, as well as triazin based polymers with piperazine-1, 4-diyl bridge members and morpholin-1 -yl end groums can be included as component c) in the flame-retardant compositions of the present invention.

Surprisingly, a flame-retardant composition comprising components a), b) and optionally c) show an excellent flame-retardancy combined with reduced wear on machine parts and with reduced flowability during processing in different plastic articles.

The present invention thus relates to a flame-retardant polymer composition comprising: a) a phospinate as defined above, 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, 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 defined above, c) optionally a nitrogen compound, phosphorus compound or phosphorus nitrogen compound, and d) a polymer

The amount of flame-retardant a) in the flame-retardant polymer composition of the invention may also vary in a broad range. Typically, the amount of component a) is 5 to 50 % by weight, preferably 7.5 to 40 % by weight and most preferred 10 to 30 % 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 0 to 40 % by weight, preferably 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 polymer d) in the flame-retardant polymer composition of the invention may vary in a broad range. Typically, the amount of component d) is 40 to 90 % by weight, preferably 50 to 85 % by weight and most preferred 60 to 80 % 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 d) and optionally c) may vary over a broad range.

The weight ratio of component(s) a) to component(s) b) is preferably between 1 : 10 and 10: 1, more preferred between 5: 1 and 1: 1.

The weight ratio of component(s) a) to component(s) c) is preferably between 1 : 1 and 10: 1, more preferred between 5: 1 and 1: 1.

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.

Component d) 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 im ides, 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, PHB and starch.

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

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

Components d) are preferably free-flowing polyamides and polyesters.

When using the polymer composition according to the invention, the corrosion of metal parts of the plasticizing unit and/or the nozzle during compounding or injection molding of the polymers, preferably of polyesters and/or polyamides is inhibited.

The polymer moldings thus produced are highly resistant to migration.

In the case of polyamides, the polymers are preferably those of the amino acid type and/or of the diamine-dicarboxylic acid type.

The polyamides are preferably polyamide 6, polyamide 12, partially aromatic polyamides and/or polyamide 66. Preference is given to these being partially crystalline polyamides. Suitable partially aromatic, partially crystalline polyamides are either homopoly amides or copolyamides, the recurring units of which are derived from dicarboxylic acids and diamines and from aminocarboxylic acids or the corresponding lactams. Suitable dicarboxylic acids are aromatic and aliphatic dicarboxylic acids such as, for example, terephthalic acid, isophthalic acid, adipic acid, azeiainic acid, sebacic acid, dodecanedicarboxylic acid and 1 ,4-cyclohexanedicarboxylic acid. Suitable diamines are aliphatic and cycloaliphatic diamines such as hexamethylenediamine, nonamethylenediamine, decamethylendiamine, dodecamethylenediamine, 2-methylpentamethylenediamine,

1 ,4-cyclohexanediamine, di (4-diaminocyclo-hexyl)-methane, di (3-methyl-4- aminocyclohexyl)-methane. Suitable aminocarboxylic acids are aminocaproic acid and aminolauric acid, which can also be used in the form of the corresponding lactams, caprolactam and laurolactam.

The melting points of these partially aromatic polyamides are between 280 and 340 °C, preferably between 295 and 325 °C.

Particularly preferred among the polyamides are those formed from terephthalic acid (TPS), isophthalic acid (IPS) and hexamethyldiamine or from terephthalic acid, adipic acid and hexamethyldiamine. As favorable conditions, approximately 70:30 TPS: IPS and 55:45 TPS: adipic acid have been found. The superior properties are realized in particular by these two special polyamides.

Preference is given to polyamides which contain phenylenediamines or xylylene- diamines as aromatic diamines.

Preference is given to polyamides which contain terephthalic acid or isophthalic acid as aromatic dicarboxylic acids.

Copolyamides are those products made from more than one polyamide-forming monomer. By selecting the monomers and the mixing ratio, the properties of the polyamides can be varied within a very wide range. Compared with the aliphatic copolyamides, certain copolyamides with aromatic monomers are interesting industrial products. They are characterized by a higher glass transition temperature and by a higher melting point of the partially crystalline regions and thus with sufficient for practical use heat resistance. Thus, starting from terephthalic acid and/or isophthalic acid and polyamines such as hexamethylenediamine, semicrystalline polyamides having high heat resistance can be prepared.

Partially aromatic copolyamides suitable according to the invention are described, for example, in Becker / Braun Kunststoff Handbuch 3/4, Polyamides, edited by L. Bottenbruch and R. Binsack, Chapter 6, partially aromatic and aromatic polyamides, pages 803 - 845, to which reference is expressly made.

Partly aromatic copolyamides which are suitable according to the invention may also be block copolymers of the abovementioned polyamides with polyolefins, olefin copolymers, ionomers, or chemically bonded or grafted elastomers; or with polyethers, such as. B. with polyethylene glycol, polypropylene glycol or polytetramethylene glycol. Further modified with EPDM or ABS polyamides or copolyamides; and during processing condensed polyamides ("IM polyamide systems").

Polyesters are preferably selected from the group of reaction products of aromatic or aliphatic dicarboxylic acids or their reactive derivatives (e.g. dimethyl esters or anhydrides) and aliphatic, cycloaliphatic or araliphatic diols and mixtures of these reaction products.

Polyalkylene terephthalates are preferably used. These can be prepared from terephthalic acid (or its reactive derivatives) and aliphatic or cycloaliphatic diols having 2 to 10 carbon atoms by known methods (Kunststoff-Handbuch, Vol. VIII, p. 695 FF, Karl-Flanser-Verlag, Munich 1973).

Polyethylene terephthalate or polybutylene terephthalate or mixtures of both polyesters are particularly preferred. The flame-retardant polymer composition of the present invention may contain further additives as component e).

The amount of component e) may vary in a broad range. Typical amounts of component e) are between 0 and 60 % by weight, preferably between 1 and 50 % by weight and more preferred between 5 and 30 % by weight, referring to the total amount of the flame-retardant polymer composition.

Examples of additives e) 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, antidripping agents, 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, carbon fibers, aramid fibers, potassium titanate whiskers, glass fibers being preferred. The incorporation of the reinforcing agents in the molding compositions can be done either in the form of endless strands (rovings) or in cut form (short glass fibers). To improve the compatibility with the polymer matrix, the reinforcing fibers used can be equipped with a size and an adhesion promoter. The diameter of commonly used glass fibers is typically in the range of 6 to 20 microns.

These additives e) 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), d) and optionally c) and/or e), e.g. by mixing or by incorporation into a masterbatch, and by incorporating the components a), b) and optionally c) and/or e) into the polymer or polymer mixture.

The flame-retardant components a), b) and optionally c) can be incorporated into the polymer d) by premixing all components as powder and/or granules in a mixer and then homogenizing them in the polymer melt in a compounding unit (e.g. a twin-screw extruder). The melt is usually withdrawn as a strand, cooled and granulated. The components a), b) and optionally c) can also be introduced separately via a metering system directly into the compounding unit. It is also possible to admix the flame-retardant components a), b) and optionally c) to a finished polymer granulate or powder and to process the mixture directly to form parts, e.g. on an injection molding machine.

The process for the production of flame-retardant polymer compositions is characterized by incorporating and homogenizing the flame retardant, components a), 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 flame-retardant, non-corrosive polymer compositions according to the invention are suitable for the production of moldings, e.g. films, threads and fibers, for example by injection molding, extrusion or compression.

The invention also relates to a molding prepared from a composition containing components a), b), d) and optionally c) and/or e).

Fire safety of electrical and electronic equipment is specified in product safety regulations and standards. In the US, fire safety testing and approval procedures are performed by Underwriters Laboratories (UL). The UL regulations are now accepted worldwide. The fire tests for plastics have been developed to determine the resistance of the materials to ignition and flame propagation.

Depending on the fire safety requirements, the materials must pass horizontal burning tests (UL 94 HB class or the more stringent vertical tests (UL 94 V-2, V-1 or V-0).) These tests simulate low energy sources of ignition that occur in electrical equipment and may affect plastic parts of electrical assemblies.

The invention furthermore relates to the use of the compositions comprising components a), b) and optionally c) as a flame retardant.

Finally, the invention relates to the use of the polymer compositions comprising components a), b), d) and optionally c) and/or e) for the manufacture of flame- retarded polymer molding compositions, which are processed by injection moulding (e.g. by using an injection molding machine of Aarburg Allrounder type), compression molding, foam injection molding, internal gas pressure injection molding, blow molding, film casting, calendering, laminating or coating at elevated temperatures.

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 ZnCI₂, 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) NaOFI 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) NaOFI 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)(OFI)

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) NaOFI 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-Hydroxy-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 %

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

250.00 g (1.08 mol) DOPO-OFI) 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-OFI)(OFI)

10.00 g (0.043 mol) DOPO-OFI 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).

Application Examples Components used

Commercially available polymer granules: VESTAMID^® HTplus M1000 (polyphthal-amide, PPA) supplied by Evonik

Glass fibers: HP 3610 supplied by PPG.

Lubricants: Licolub^® WE 40 powder supplied by Clariant (ester of montanic acids) Flame retardant components:

Exolit^® OP 1230 by Clariant (Aluminum salt of diethylphosphinic acid, DEPAL)

DOPO metal OH complexes according to section 1, Synthesis Examples

Production, processing and testing of flame-retardant plastic molding compounds and their corrosion behavior

The flame-retardant components were mixed in the ratio indicated in the table and incorporated via the side feeder of a twin-screw extruder (Leistritz ZSE 27 / 44D) at temperatures between 310-320 °C in PPA. The glass fibers were added via a second side feed. The homogenized polymer strand was stripped off and cooled in a water bath.

After sufficient drying, the molding compositions were processed on an injection molding machine (type Arburg 320 C Allrounder) at mass temperatures of 310 to 320 °C to test specimens and tested and classified by the UL 94 test (Underwriter Laboratories) on flame retardancy and classified.

According to UL 94, the following fire classes result:

V-0: no afterburning for more than 10 seconds, sum of afterburning times for 10 flame treatments not greater than 50 seconds, no burning dripping, no complete burning off of the sample, no afterglowing of the samples longer than 30 seconds after end of flame.

V-1 : no afterburning longer than 30 sec after end of flame, sum of afterburning times with 10 flame treatments not greater than 250 sec, no afterglowing of samples longer than 60 sec after flaming end, other criteria as for V-0.

V-2: ignition of the cotton by burning dripping, other criteria as in V-1.

Not classifiable (ncl): does not meet

The flowability of the molding compositions was determined by determining the melt volume index (MVR) at 330 °C / 5.00 kg. Higher MVR values mean better flowability in the injection molding process. However, a strong increase in the MVR value may also indicate polymer degradation.

The corrosion was examined by the platelet method.

The platelet method developed at DKI (Deutsches Kunststoffinstitut, Darmstadt, now part of Fraunhofer LBF) is used for model investigations for the comparative evaluation of metallic materials and the corrosion and wear intensity of plasticizing molding compounds. In this test, two specimens are placed in pairs in the nozzle so that they form a rectangular gap of 12 mm length, 10 mm width and a height of 0.1 to a maximum of 1 mm adjustable height for the passage of the plastic melt (Fig. 1). Through this gap, plastic melt is extruded (or sprayed) from a plasticizing unit with the appearance of large local shear stresses and shear rates in the gap.

A measurement for occurring wear is the weight loss of the specimens, which is determined by differential weighing of the specimens with an A & D Electronic Balance analytical balance with a deviation of 0.1 mg. The mass determination of the specimens was carried out before and after the corrosion test with 10 kg compound.

After the test pieces are removed and physically / chemically cleaned of the adhering plastic. The physical cleaning is done by removing the hot plastic mass by rubbing with a soft material (cotton). Dry cleaning is carried out by heating the specimens at 60 °C in m-cresol for 20 minutes.

All tests of the respective series were carried out, if no other details were given, because of the comparability under identical conditions (temperature programs, screw geometries, injection molding parameters, etc.). Unless stated otherwise, quantities are always % by weight.

Temperature profile: 310-310-310-315-320-320-320 °C

Steel for corrosion test: CK45

Throughput: 7-8 kg/h

Amount of compound used in tests: 10kg

Table 1 , trial 1 , shows that with DEPAL in partially aromatic polyamide in 15 % dosage a V-0 is achieved. As this combination is used as reference formulation in corrosion testing, the corrosion reduction is set to 0 %. Nevertheless, a significant corrosion occurs for this formulation.

Table 1 , trial 2 (comparative) shows the effect of the combination of Exolit OP 1230 in combination with Zn(DOPO)₂. In this test corrosion increases 66 % compared to the reference probe.

It has now surprisingly been found that when DEPAL and metal-DOPO-hydroxide complexes are combined according to the present invention (Table 1, trials 3-9), the corrosion is significantly reduced while simultaneously flowability is improved. Table 1 : Results of application tests

Claims

Patent Claims

1. A composition comprising a) a phosphinate, and 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, 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.

2. The composition according to claim 1 , wherein the phosphinate is a compound of formula (XV), wherein

R¹ and R² indepdendently of one another are the same or different and are alkyl and/or aryl, preferably C₁-C₆-alkyl and/or phenyl,

M is a metal selected from Cu, Ca, Mg, Zn, Mn, Fe, Al, Co, Ni, Sn, Zr, ZrO, Ce, MoO, WO₂, VO, La, Ti, TiO or Sb, preferably selected from Zn, Al, Fe or TiO, m is an integer from 1 to 3, and n is a number with value 1/m.

3. The composition according to claim 2, wherein R¹ and R²are identical or different and are methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, n-pentyl and/or phenyl.

4. The composition according to claim 2, wherein R¹ and R² each are C₁-C₆-alkyl, preferably methyl, ethyl, propyl or butyl, and wherein M is Zn, Fe, TiO orAI, preferably Al.

5. The composition according to at least one of claims 1 to 4, wherein component b) is a metal complex having the structure of formulae (V), (VI) or (VII) wherein Me and Y are as defined in claim 1 , x is 2, 3 or 4, a is 1 or 2, b is a number with value a + x, and c is a number ³1 , 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.

6. The composition according to claim 5, wherein all Me-ions in a complex comprising several Me-ions contain at least one OH--ion ligand.

7. The composition according to at least one of claims 1 to 6, wherein the metal ions Me included in the complex are selected from the group consisting of Mg, Ca, Zn, Mn, Fe, Ti, TiO, Al, Sn and/or Ce, most perferably selected from the group consisting of Zn, TiO, Al, Sn and/or Ce.

8. The composition according to at least one of claims 1 to 7, wherein an additional component c) is present which is selected from nitrogen compounds, phosphorus compounds or phosphorus nitrogen compounds or mixtures of two or more thereof.

9. A flame-retardant polymer composition comprising components a) and b) according to claim 1 and d) a polymer.

10. The flame-retardant polymer composition according to claim 9, wherein an additional component c) according to claim 8 is present.

11. The flame-retardant polymer composition according to claim 9, wherein the amount of polymer d) is 40 to 90 % by weight, the amount of flame-retardant a) is 5 to 50 % by weight, and the amount of flame-retardant b) is 5 to 40 % by weight, all amounts referring to the total amount of the polymer composition.

12. The flame-retardant polymer composition according to at least one of claims 9 to 11 , wherein component a) is a phosphinate of formula (XV) according to claim 2.

13. The flame-retardant polymer composition according to at least one of claims 9 to 12, wherein the metal complexes b) have the structures of formulae (V), (VI) or (VII) according to claim 5.

14. The flame-retardant polymer composition according to claim 13, wherein the metal complexes b) have the structure of formula (VII) in which Y = S.

15. The flame-retardant polymer composition according to at least one of claims 9 to 14, wherein the polymer d) is a thermoplastic polymer, preferably selected from the group consisting of polyamides, polyesters, polyurethanes, polycarbonates or epoxy resins.

16. The flame-retardant polymer composition according to claim 15, wherein the polymer d) is a polyamide or a polyester, preferably a glass fiber reinforced polyamide or polyester.

17. The flame-retardant polymer composition according to at least one of claims 9 to 16, wherein the polymer composition contains further additives as component e).

18. The flame-retardant polymer composition according to claim 17, wherein the additive e) is a filler and/or a reinforcing agent.

19. A molding containing components a), b) and d) according to claim 9.

20. Use of a composition comprising components a), b) and optionally c) according to at least one of claims 1 to 8 as a flame retardant.

21. Use of a flame-retardant polymer composition according to at least one of claims 9 to 18 for the manufacture of flame-retarded polymer molding compositions, which are processed by injection moulding, compression molding, foam injection molding, internal gas pressure injection molding, blow molding, film casting, calendering, laminating or coating at elevated temperatures.