FIELD OF THE INVENTION

The present invention relates to a flame retardant polyamide composition comprising a polyamide component, a polyketone component and a flame retardant, and also to an article produced from the same.

BACKGROUND OF THE INVENTION

Various polymer blends have been developed and commercialized either for synergistic performance or for cost-performance balance. In recent years, there is an increasing interest in blends of polyamide (PA) and polyketone (POK) due to their compatibility with each other and the complementary properties thereof. The blends of PA and POK may combine advantages of both polymers and thus allow to provide materials with balanced mechanical properties, good chemical resistance and low moisture absorption.

Polyamide (also referred to as nylon) is a kind of polymer containing repeating amido moieties (-CONH-) in main chains, which has already been widely used as a base resin for engineering plastic for years in various industries such as automotive and appliance due to its good processibility, mechanical properties and low cost. Polyamide materials having various structural units are known, among which polyamide 6 (polycaprolactam, also referred to as PA6 or nylon 6) and polyamide 66 (poly(hexamethylene adipamide), also referred to as nylon 66) are most common for textile and plastic industries for their outstanding performances and cost ratios. Especially, polyamide materials are widely used in automotive applications. On average, more than 6kg of polyamide materials would be used per one car. Many of the automotive applications, such as power train components which generate and deliver power to the wheels, require polyamide materials to exhibit good mechanical performance, high heat resistance and dimension stability.

Polyketone, a relatively new type of thermoplastic copolymers of carbon monoxide and olefins, could help to remedy shortcomings of polyamide materials in the dimension stability and some mechanical properties such as tensile stiffness and Izod impact strength, which broadens the field of application of polyamide materials. However, polyketone material has a drawback of inferior heat-aging performance, which largely constrained its application in high performance engineering plastic field.

Blends of polyamide with polyketone have been developed to combine their complimentary properties and broaden application fields of both materials. Certain blends of polyamide with polyketone further comprise a flame retardant for those applications where a flame retardant property is required. For example, CN 107974076A discloses a flame retardant PA6/POK alloy material comprising 50 to 90 parts by weight of a nylon resin, 10 to 50 parts by weight of a polyketone resin, 10 to 20 parts by weight of a flame retardant, 4 to 8 parts by weight of a flame retardant synergist, 3 to 6 parts by weight of a compatilizer, 20 to 35 parts by weight of chopped fiber, 0.35 to 0.65 parts by weight of an antioxidant, 0.4 to 0.7 parts by weight of a lubricant. The POK is required to have a high intrinsic viscosity between 2.0 to 2.6. It was described in the patent application that the alloy material could provide molding parts having improved properties such as water absorption, dimension stability and mechanical property compared with PA6.

CN 106700525A discloses a high impact halogen-free flame retardant PA6/POK alloy material which consists of 200 to 400 parts of POK, 400 to 700 parts of PA6, 10 to 100 parts of a compatible impact-modifying agent, 50 to 150 parts of a halogen-free flame retardant and 5 to 15 parts of other additives. In Examples of the patent application, a POK having a high intrinsic viscosity (i.e., M630 from Hyosung Co. Ltd) was used for preparing the alloy material. It was described in the patent application that the flame retardant PA6/POK alloy material has good mechanical performance, especially improved impact strength, heat deflection temperature and wear-resistance, as compared with corresponding PA6.

In the flame retardant PA/POK blends as described in those patent applications, POKs having a high intrinsic viscosity were used. Such blends do not have sufficient flowability for certain processing processes, for example injection molding. It has been found by the inventors of the present invention that such PA/POK blends based on M630 cannot even be prepared successfully when a higher amount of flame retardant and/or a reinforcing agent need to be used.

There is a need to provide a PA/POK blend having an improved processibility, especially flowability while providing desired flame retardancy. It will be desirable if a PA/PK blend having above properties could be provided without a sacrifice of mechanical properties such as toughness, good tensile strength and/or heat aging performance.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a flame retardant polyamide material having improved flowability while providing desired flame retardancy, without sacrifice of mechanical properties such as toughness, good tensile strength and/or heat aging performance.

Accordingly, the present invention provides a polyamide composition, which comprises

- from 10% to 65% by weight of a polyamide as component (A),

- from 5% to 45% by weight of a polyketone as component (B), which has a weight average molecular weight (Mw) in the range of 80,000 to 250,000,

- from 10% to 25% by weight of a flame retardant as component (C), and

- from 5% to 50% by weight of a reinforcing agent as component (D), each being based on the total weight of the polyamide composition. The present invention also provides an article produced from the polyamide composition as described herein.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be described in detail hereinafter. It is to be understood that the present invention can be embodied in many different ways and shall not be construed as limited to the embodiments set forth herein.

The singular forms “a”, “an” and “the” include plural referents unless the context clearly dictates otherwise. The terms “comprise”, “comprising”, etc. are used interchangeably with “contain”, “containing”, etc. and are to be interpreted in a non-limiting, open manner. That is, e.g., further components or elements can be present. The expressions “consists of” or “consisting of” or cognates can be embraced within “comprises” or “comprising” or cognates.

As used herein, the term “structural unit(s)” is intended to refer to the minimal molecular residue(s) resulting from respective monomer molecules after polymerization. For example, PA6 has a type of structural unit of -NH(CH ₂ )sCO-, PA66 has two types of structural units, i.e. , -NH(CH ₂ ) ₆ NH- and -CO(CH ₂ ) ₄ CO-, and so on.

As used herein, the term “repeating unit(s)” is intended to refer to the minimal unit(s) with same chemical composition in a polymer. The repeating units can consist of one or more types of structural units. For example, PA6 has repeating units same as the structural units, i.e., - NH(CH ₂ )SCO-; PA66 has repeating units of -NH(CH ₂ )6NHCO(CH ₂ )4CO- which consist of two types of structural units, i.e., -NH(CH ₂ )eNH- and -CO(CH ₂ )4CO-.

Component (A)

Polyamide, as well known in the art, refers to a polymer that contains repeating amide groups (-CONH-) in the main chain of the polymers. Generally, a polyamide is made up of many identical repeating units linked by covalent bonds.

Useful polyamide may be typically derived from a monomer selected from the group consisting of lactams, amino acids, a combination of dicarboxylic acid and diamine, and a combination of dicarboxylic acid chloride and diamine.

Such polyamide as component (A) in the polyamide composition according to the present invention may have repeating units of formula (I): o

-+ r NH-R - ¹ i-C ¹¹ i - _(|)J in which

R ¹ is a hydrocarbylene group having from 3 to 29 carbon atoms, preferably from 5 to 17 carbon atoms, more preferably from 5 to 11 carbon atoms. Particularly, R ¹ in formula (I) is an alkylene or cycloalkylene group, more preferably an alkylene group, having a number of carbon atoms as described herein.

The polyamide having repeating units of formula (I) is typically derived from at least one aliphatic monomer selected from the group consisting of (1) lactams having from 4 to 30 carbon atoms and (2) amino acids having from 4 to 30 carbon atoms.

Suitable lactams preferably have from 6 to 18 carbon atoms, more preferably from 6 to 12 carbon atoms. Examples of the lactams may include, but are not limited to, caprolactam, caprylolactam, caprinolactam, undecanolactam, laurolactam, or any combinations thereof.

Suitable amino acids preferably have from 6 to 18 carbon atoms, more preferably from 6 to 12 carbon atoms. Examples of the amino acids may include, but are not limited to, 2-aminoadipic acid, 9-aminononanoic acid, 10-aminodecanoic acid, 11-aminoundecanoic acid, 12- aminododecanoic acid, or any combinations thereof.

Alternatively, the polyamide as component (A) in the polyamide composition according to the present invention may have repeating units of formula (II): o o

-|-NH-R ² -NH— C— R ³ -C-|- in which

R ² is a hydrocarbylene group having from 4 to 24 carbon atoms, preferably from 4 to 18, and R ³ is a hydrocarbylene group having from 4 to 30 carbon atoms, preferably from 4 to 20.

Particularly, R ² in formula (II) is an alkylene or cycloalkylene group, preferably an alkylene group, having a number of carbon atoms as described herein. Alternatively or additionally, R ³ in formula (II) is an alkylene, cycloalkylene or arylene group, preferably an alkylene or arylene group, having a number of carbon atoms are described herein.

The polyamide having repeating units of formula (II) is typically derived from monomers which are selected from the group consisting of (1) a combination of dicarboxylic acids having from 6 to 32 carbon atoms and diamines having from 4 to 24 carbon atoms and (2) a combination of dicarboxylic acid chlorides having from 6 to 32 carbon atoms and diamines having from 4 to 24 carbon atoms.

Suitable aliphatic diamines preferably have from 4 to 24 carbon atoms, more preferably from 4 to 18 carbon atoms, for example 4, 5, 6, 7, 8, 9, 10, 11 , 12, 13 or 14 carbon atoms. The aliphatic diamines may be linear or branched aliphatic diamines. Examples of the aliphatic diamines may include, but are not limited to, 1 ,4-butanediamine, 1 ,5-pentanediamine, 1 ,6- hexanediamine, 1 ,7-heptanediamine, 1 ,8-octanediamine, 1 ,9-nonanediamine, 1 ,10- decanediamine, 1 ,11-undecanediamine, 1 ,12-dodecanediamine, 1 ,13-tridecanediamine, 1 ,14- tetradecanediamine, 1 ,16-hexadecanediamine, 1 ,18-octadecanediamine, 1 ,20- eicosanediamine, 1 ,22-docosanediamine, 2-methylpentane-1 ,5-diamine, 3-methylpentane- 1 ,5-diamine, 2,5-dimethylhexane-1 ,6-diamine, 2,4-dimethylhexane-1 ,6-diamine, 3,3- dimethylhexane-1 ,6-diamine, 2,2-dimethylhexane-1 ,6-diamine, 2,2,4-trimethylhexane-1 ,6- diamine, 2,4,4-trimethylhexane-1 ,6-diamine, 2,3-dimethylheptane-1 ,7-diamine, 2,4- dimethylheptane-1 ,7-diamine, 2,5-dimethylheptane-1 ,7-diamine, 2,2-dimethylheptane-1 ,7- diamine, 2-methyloctane-1 ,8-diamine, 1 ,3-dimethyloctane-1 ,8-diamine, 1 ,4-dimethyloctane-

1.8-diamine, 2,4-dimethyloctane-1 ,8-diamine, 3,4-dimethyloctane-1,8-diamine, 4,5- dimethyloctane-1 ,8-diamine, 2,2-dimethyloctane-1 ,8-diamine, 3,3-dimethyloctane-1 ,8- diamine, 4,4-dimethyloctane-1 ,8-diamine, 2,4-diethylhexane-1 ,6-diamine, 5-methylnonane-

1.9-diamine, and any combinations thereof.

Suitable dicarboxylic acids may be aliphatic or aromatic and have from 6 to 32, preferably 6 to 22 carbon atoms, for example 6, 7, 8, 9,10, 11 , 12, 13, 14, 15, 16, 17, 18, 19 or 20 carbon atoms. Examples of the dicarboxylic acids may include, but are not limited to, adipic acid, pimelic acid, sebacic acid, undecanedioic acid, dodecandioic acid, tridecanedioic acid, tetradecandioic acid, pentadecandioic acid, hexadecanedioic acid, octadecandioic acid, terephthalic acid, isophthalic acid, and any combinations thereof.

Suitable dicarboxylic acid chlorides may be aliphatic or aromatic and have from 6 to 32, preferably 6 to 22 carbon atoms, for example 6, 7, 8, 9, 10, 11 , 12, 13, 14, 15, 16, 17,18, 19 or 20 carbon atoms. Examples of the dicarboxylic acid chlorides may include, but are not limited to, adipoyl dichloride, heptanedioyl dichloride, azelaoyl dichloride, sebacoyl dichloride, undecanedioyl dichloride, lauroyl dichloride and any combinations thereof.

For example, the polyamide as component (A) may be at least one selected from the group consisting of PA6, PA7, PA8, PA9, PA11 , PA12, PA410, PA510, PA513, PA515, PA66, PA69, PA610, PA612, PA613, PA614, PA618, PA636, PA88, PA810, PA812, PA1010, PA1012, PA1014, PA1018, PA1210, PA1212, PA1214, PA1218, PA1313, PA1410, PA1412, PA1414, PA1418, PA4T, PA9T, PA10T, PA11T and any combinations thereof.

Useful polyamide may also be a blend of polyamides as described above or a copolymerized polyamide (co-polyamide). There is no limitation to the type of the co-polyamide, which may be for example a block copolymer, a random copolymer, a graft copolymer or an alternating copolymer. Examples of the co-polyamide may include, but are not limited to, PA6/PA510, PA6/PA610, PA6/PA612, PA6/PA1010, PA66/PA410, PA66/PA510, PA66/PA610, PA66/PA612, PA66/PA1010, PA6/6T (mole ratio of 6 to 6T from 1 :99 to 99:1), PA66/6T (mole ratio of 66 to 6T from 1 :99 to 99:1), PA6T/6I (mole ratio of 6T:6I from 99:1 to 65:35).

In some embodiments according to the present invention, the polyamide having the repeating units of formula (I) as described herein is particularly useful as component (A) in the polyamide composition. The polyamide having the repeating units of formula (I) in which R ¹ having 5 to 11 carbon atoms is more preferably useful as component (A) in the polyamide composition, among which PA6 is most preferable. The polyamide as component (A) in the polyamide composition according to the present invention may have any suitable molecular weights without being limited. Preferably, the relative viscosity of the polyamide is from 1.8 to 4.0, as measured in 96 % by weight sulfuric acid at 25°C.

The component (A) is present in the polyamide composition according to the present invention in an amount of from 10% to 65% by weight, for example from 10% to 40% by weight, or from 20% to 40% by weight, based on the total weight of the polyamide composition.

The polyamide disclosed herein should not be limited to the ones prepared from virgin crude oil monomers, and could be completely or at least partially biobased or derived from waste stream or recycling activities, i.e. , the polyamide used in the present application can be based on renewable materials, secondary raw materials or recycled raw materials. For example, PA6, PA9, PA66, PA9T, PA10T and PA11T used as component (A) in the present application could be prepared or obtained or derived from monomers that obtained in a re-monomerisation processes.

Component (B)

Polyketone generally refers to a class of polymers which are derived from carbon monoxide and an olefinically unsaturated monomer. Useful polyketone as component (B) in the polyamide composition according to the present invention may have at least one type of repeating units of formula (III): wherein R ⁴ , R ⁴ ’, R ⁵ and R ⁵ ’ are each independently hydrogen or hydrocarbyl group having from

1 to 40 carbon atoms, preferably from 1 to 20 carbon atoms, more preferably from 1 to 10 carbon atoms, most preferably from 1 to 5 carbon atoms.

The polyketone as component (B) may have one or more types of the repeating units of formula (III) as described herein. For example, the polyketone as component (B) may have at least two types of the repeating units of formula (III).

Suitable olefinically unsaturated monomers may include for example alpha-olefins having from

2 to 10 carbon atoms and substituted derivatives thereof, and monocyclic or polycyclic aromatic monomers having from 6 to 30 carbon atoms and alkyl substituted derivatives thereof. Particularly, the olefinically unsaturated monomers are selected from alpha-olefins having from 2 to 8 carbon atoms, such as ethene, propene, butene, isobutene and pentene. It is preferred that the olefinically unsaturated monomers are ethene or a mixture of ethene and an additional alpha-olefin having from 3 to 6 carbon atoms, especially propene or butene. It is further preferred that the molar ratio of ethene to the additional alpha-olefin having from 3 to 6 carbon atoms is greater than or equal to 1 , for example, in the range of 2 to 30. In some embodiments according to the present invention, the polyketone as component (B) in the polyamide composition according to the present invention may be a copolymer of ethene/CO, propene/CO, ethene/propene/CO or butene/CO, wherein CO represents carbon monoxide.

The polyketone as component (B) has a weight average molecular weight (Mw) in the range of 80,000 to 250,000, for example 100,000 to 200,000 or 100,000 to 150,000.

Additionally, the polyketone as component (B) may have a number average molecular weight (Mn) in the range of 40,000 to 85,000, for example 50,000 to 80,000 or 50,000 to 70,000.

Additionally or alternatively, the polyketone as component (B) preferably has a polydispersity index in the range of 1 .5 to 3.0, for example 2.0 to 2.5.

In some embodiments according to the present invention, the polyketone as component (B) preferably has a weight average molecular weight (Mw) in the range of 100,000 to 150,000 and/or has a number average molecular weight (Mn) in the range of 50,000 to 70,000.

The polyketone as component (B) may have a melt flow rate of from 20 to 350 g/10min, for example, from 40 to 300 g/10min, as measured at 240 °C with 2.16kg.

The polyketone as component (B) may have an intrinsic viscosity (IV) of from 0.8 to 1.8 dL/g, for example from 0.8 to 1.6 dL/g, as measured in a capillary viscometer using hexafluoroisopropyl alcohol at 25°C as the solvent.

For the purpose of the present invention, the polyketone may be those prepared via known processes or be commercially available polyketone materials. Examples of commercially available polyketone materials include, but are not limited to, POKETONE series from Hyosung Co. Ltd, such as POKETONE™ M330 and POKETONE™ M930.

The component (B) is be present in the polyamide composition according to the present invention in an amount of from 5% to 45% by weight, for example from 5% to 40% by weight, or from 8 % to 30% by weight, based on the total weight of the polyamide composition.

The component (A) and the component (B) may be present in the polyamide composition according to the present invention at a weight ratio (A : B) of in the range of 1 : 2 to 50 : 1 , for example 1 : 2 to 10 : 1 , or 1 : 1 to 4 : 1.

Component (C)

Flame retardant, also known as fire retardant, is a functional additive that imparts flame retardancy to flammable polymers. Any known flame retardants may be used in the polyamide composition according to the present invention without a particular restriction, including for example metal hydroxide based flame retardants, metal salt based flame retardants, silicon based flame retardants, nitrogen based flame retardants, boron based flame retardants, antimony based flame retardants, phosphorus based flame retardants, and halogen based flame retardants.

Particularly, the flame retardant as component (C) may be selected from phosphorus based flame retardants, halogen based flame retardants, or a combination thereof.

The phosphorus based flame retardants have advantages of low smoke, non-toxic, and halogen-free. Suitable phosphorus based flame retardants may be inorganic, for example red phosphorus, metal or ammonium salts of phosphoric acid, pyrophosphoric acid, polyphosphoric acid, phosphorous acid and phosphinic acid; or organic, for example organic phosphate salt or esters, phosphite salt or esters, phosphonate salt or esters, phosphinate salt or esters, pyrophosphate salt or esters, polyphosphate salt or esters; or a combination thereof.

As the inorganic phosphorus based flame retardants, metal or ammonium salts of phosphorous acid of formula (IV)

[H _n P(=O)O ₂ ] M (3-n)/m (IV) in which

M represents a cation of ammonium or metal selected from Mg, Ca, Al, Sb, Sn, Ge, Ti, Zn, Fe, Zr, Ce, Bi, Sr, Mn, Li, Na, K, a protonated nitrogen base, or a combination thereof, m represents a number equivalent to the valence of M, in the range of 1 to 4, and n represents a number of H in the range of 1 or 2, and hydrates thereof, corresponding basic salts, or any combinations thereof, may be particularly mentioned.

Examples of metal salts of phosphorous acid may include, but are not limited to AI(H ₂ PO3)3, AI ₂ (HPO ₃ ) ₃ , Zn(HPO ₃ ), AI ₂ (HPO ₃ ) ₃ 4H ₂ O, AI(OH)(H ₂ PO ₃ ) ₂ '2H ₂ O or any combinations theroef.

As the inorganic phosphorus based flame retardants, metal phosphinates such as Mg, Ca, Al or Zn phosphinates may also be particularly mentioned. Particular preference is given to aluminum phosphinate.

The organic phosphorus based flame retardants may particularly include ethylenediamine phosphate, piperazine phosphate, piperazine pyrophosphate and metal organophosphinate.

As the organic phosphorus based flame retardants, organophosphinate salts, preferably phosphinate salts of formula (V), diphosphinate salts of formula (VI), or polymers thereof, or any combinations thereof may be particularly mentioned: in which one of R ⁶ and R ⁶ ' represents hydrogen, linear or branched Ci-Ce-alkyl, or aryl, and the other independently represents linear or branched Ci-Ce-alkyl, or aryl,

M represents Mg, Ca, Al, Sb, Sn, Ge, Ti, Zn, Fe, Zr, Ce, Bi, Sr, Mn, Li, Na, K, a protonated nitrogen base, or a combination thereof, and m represents a number equivalent to the valence of M, in the range of 1 to 4; in which

R ⁷ and R ⁷ ' independently represents hydrogen, linear or branched Ci-Ce-alkyl, or aryl,

R ⁸ represents linear or branched Ci-Cw-alkylene, Ce-Cw-arylene, Ce-Cw-alkylarylene or Ce- Cw-arylalkylene,

M represents Mg, Ca, Al, Sb, Sn, Ge, Ti, Zn, Fe, Zr, Ce, Bi, Sr, Mn, Li, Na, K, a protonated nitrogen base, or a combination thereof, and m represents a number equivalent to the valence of M, in the range of 1 to 4.

Metal dialkylphosphinate salts of formula (V) are preferred, wherein R ⁶ and R ⁶ ’ independently represent methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, n-pentyl or phenyl, more preferably methyl, ethyl, n-propyl, and M is Al, Mg, Ca, Zn or any combinations thereof. More preferably, M is Al in formula (V).

Examples of preferable phosphinates of formula (V) may include, but are not limited to metal dialkylphosphinates selected from aluminum dimethylphosphinate, calcium dimethylphosphinate, magnesium dimethylphosphinate, zinc dimethylphosphinate, aluminum ethylmethylphosphinate, calcium ethylmethylphosphinate, magnesium ethylmethylphosphinate, zinc ethylmethylphosphinate, aluminum diethylphosphinate, calcium diethylphoshinate, magnesium diethylphosphinate, zinc diethylphosphinate, aluminum methyl- n-propylphosphinate, calcium methyl-n-propylphosphinate, magnesium methyl-n- propylphosphinate, zinc methyl-n-propylphosphinate or any combinations thereof, among which aluminum dimethylphosphinate, zinc dimethylphosphinate, aluminum diethylphosphinate, zinc diethylphosphinate and any combinations thereof are more preferable.

Metal diphosphinate salts of formula (VI) may also be preferred, wherein R ⁷ and R ⁷ ’ independently represent hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, n- pentyl, n-hexyl or phenyl, R ⁸ preferably represents methylene, ethylene, 1 ,2-propylene, 1 ,3- propylene, 1 ,2-butylene, 1 ,4-butylene, 1 ,2-pentylene, 1 ,5-pentylene, n-octylene or n- dodecylene, phenylene or naphthylene, methylphenylene, ethylphenylene, tert-butylphenylene, methylnaphthylene, ethylnaphthylene or tert-butylnaphthylene; phenylmethylene, phenylethylene, phenylpropylene or phenylbutylene, and M is Al, Mg, Ca, Zn or any combinations thereof.

For organic phosphinate or diphosphiate flame retardants, reference may be made to DE-A 19960671 , DE-A 4430932 and DE-A 19933901 , which are incorporated herein by reference.

A combination of inorganic and organic phosphorus based flame retardants is also suitable for the present invention, for example a combination of a metal salt of phosphoric acid or phosphorous acid with a metal salt of phosphinate. Particularly, a combination of a metal salt of phosphoric acid or phosphorous acid with a metal dialkylphosphinate of formula (V) as described with preference hereinabove, for example a combination of aluminum salt of phosphoric acid or phosphorous acid and an aluminum dialkylphosphinate is useful as the phosphorus based flame retardant in the present invention.

Examples of commercially available phosphorus based flame retardants may include Exolit OP 930, Exolit OP 935, Exolit OP 945, Exolit OP 950, ExolitOP 1230, Exolit OP 1240, Exolit OP 1312, Exolit OP 1314 and Exolit OP 1400 from CLARIANT.

The halogen based flame retardants include, but are not limited to, organic chlorides and organic bromides. Suitable halogen based flame retardants are preferably brominated compounds, such as brominated diphenyl ether, brominated trimethylphenylindane, tetrabromobisphenol A, hexabromocyclododecane, brominated polystyrene, brominated polyacrylates such as brominated polybenzyl acrylates, brominated bisphenol A epoxide oligomers and brominated bisphenol A polycarbonates.

Examples of the brominated compounds include oligomeric reaction products (n>3) of tetrabromobisphenol A with epoxides (e.g., FR 2300 and 2400 from DSB) having the following structural formula:

Further examples of the brominated compounds include brominated polystyrenes having the following structural formula: which has an average degree of polymerization (number-average) between 3 and 90, preferably between 5 and 60, measured by vapor pressure osmometry in toluene. The brominated polystyrenes are typically obtained by the process described in EP-A 047 549. Examples of commericially available brominated polystyrenes include, but are not limited to Saytex® HP-7010, Saytex®HP-3010, Firemaster® PBS-64HW, PDBS-80™, Firemaster® CP44- HF, FR803P and GreatBay XZ-6700.

Suitable brominated compounds also include brominated oligocarbonates (BC 52 or BC 58 from Great Lakes) having the following structural formula: in which n is no higher than 3.

Especially suitable brominated compounds include polypentabromobenzyl acrylates having the following structural formula with n > 4 (e.g., FR-1025 from ICL):

The flame retardants can be used alone or in a mixture of flame retardants in the polyamide composition according to the present invention.

The component (C) is present in the polyamide composition according to the present invention in an amount of from 10 % to 25 % by weight, or from 15 % to 25 % by weight, based on the total weight of the polyamide composition.

Component (D)

Useful reinforcing agents as component (D) may be of various types without particular restrictions, such as fibers, whiskers, flakes and particles, but may be preferably selected from fibrous reinforcing agents and particulate fillers.

Examples of the fibrous reinforcing agents may include, but are not limited to glass fibers, carbon fibers, boron fibers, asbestos fibers, polyvinyl alcohol fibers, polyester fibers, acrylic fibers, wholly aromatic polyamide fibers, polybenzoxazole fibers, polytetrafluoroethylene fibers, kenaf fibers, bamboo fibers, hemp fibers, bagasse fibers, high strength polyethylene fibers, alumina fibers, silicon carbide fibers, potassium titanate fibers, brass fibers, stainless steel fibers, steel fibers, ceramic fibers, wollastonite fibers, and basalt fibers, among which glass fibers and carbon fibers are particularly preferred.

There is no particular restriction to the fiber length and the fiber diameter of the fibrous reinforcing agents. For example, chopped fibers having a length in the range of from 1 to 10 mm, preferably from 2 to 6 mm, or continuous fibers may be used as starting material of the reinforcing agent. The fibers will be broken down during processing, for example kneading the polyamide composition, to a length of a few hundreds of microns as present in the obtained moldings. The fiber diameter is preferably from 3 to 20 pm, more preferably from 7 to 13 pm.

Examples of the cross-sectional shape of the fibrous reinforcing agents include for example circle, rectangle, ellipse, and other non-circular cross sections, among which circle shape is especially preferred. The fibrous reinforcing agents may have a cross section with an aspect ratio in the range of from 2:1 to 5:1.

The glass fibers may have been surface-treated by a silane coupling agent, which is for example selected from vinylsilane-based coupling agents, acrylic silane-based coupling agents, epoxysilane-based coupling agents and aminosilane-based coupling agents, preferably aminosilane-based coupling agents. The silane coupling agent may be dispersed in a sizing agent. Examples of the sizing agent may include, but are not limited to acrylic compounds, acrylic/maleic derivative modified compounds, epoxy compounds, urethane compounds, urethane/maleic derivative modified compounds and urethane/amine modified compounds.

Particulate fillers may be organic or inorganic, and have a variety of particle sizes, ranging from particles in dust form to coarse particles. Examples of materials that may be used as inorganic particulate fillers include, but are not limited to kaolin, chalk, wollastonite, talc, calcium carbonate, silicates, titanium dioxide, zinc oxide, graphite, mica, vermiculite, montmorillonite, and glass particles (e.g., glass beads).

In some embodiments according to the present invention, the reinforcing agent as component (D) is selected from glass fibers. The glass fibers may be for example E-glass fibers, A-glass fibers, D-glass fibers, AR-glass fibers, C-glass fibers and S-glass fibers.

The component (D) is present in the polyamide composition according to the present invention in an amount of from 5% to 50% by weight, from 10 % to 40% by weight, or from 20% to 40% by weight based on the total weight of the polyamide composition.

The reinforcing agents as component (D) disclosed herein can also be based on renewable materials, secondary raw materials or recycled raw materials. For example, the glass fibers used herein can be recycled glass fibers, or renewable glass fibers obtained from conventional recycling treatment process.

Component (E)

Optionally, the polyamide composition according to the present invention may further comprise a flame retardant synergist, which plays a synergistic role in a flame retardant system and could improve the flame retardancy.

Examples of the flame retardant synergists useful for the polyamide composition according to the present invention may include, but are not limited to, melamine cyanurate, antimony trioxide, aluminum hydroxides such as synthetic aluminum metahydroxide (synthetic aluminum hydroxide), natural aluminum metahydroxide (natural aluminum hydroxide), magnesium hydroxide, zinc borate, polysiloxane, alumina, calcium borate, calcium carbonate, calcium magnesium carbonate, calcium oxide, calcium sulfide, iron oxide, magnesium borate, magnesium carbonate, magnesium nitride, magnesium oxide, magnesium sulfide, manganese hydroxide, manganese oxide, titanium nitride, titanium dioxide, zinc metaborate, zinc carbonate, zinc hydroxide, zinc nitrate, zinc oxide, zinc phosphate, zinc sulfide, zinc stannate, zinc hydroxystannate, base zinc silicate, tin oxide hydrate, or any combinations thereof.

Examples of commercially available flame retardant synergists may include, BIIDIT 315 E from Budenheim Iberica, S.L., and GM-F01 from Gredmann Fine Chemical Ltd.

The component (E), if comprised, may be present in the polyamide composition according to the present invention in an amount of from 1 % to 15 % by weight, or from 3 % to 9 % by weight, based on the total weight of the polyamide composition.

Component (F)

The polyamide composition according to the present invention optionally, but preferably comprises an antioxidant as component (F).

The antioxidant is preferably selected from hindered phenol-based antioxidants, phosphite- based antioxidants, aromatic amine-based antioxidants, and any combinations thereof. More preferably, the antioxidant is selected from hindered phenol-based antioxidants, phosphite- based antioxidants or any combinations thereof.

Useful hindered phenol-based antioxidants as component (F) in the polyamide composition according to the present invention may be selected from the group consisting of N,N’-hexane-

1.6-diyl bis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide) (d1) (BASF lrganox®1098),

4.6-bis(octylthiomethyl)-o-cresol (d2) (BASF Irganox® 1520), octyl-3,5-di-tert-butyl-4- hydroxyhydrocinnamate (d3), 3,5-bis(1 ,1-dimethylethyl)-4-hydroxybenzenepropanoic acid C7- C9-branched alkyl ester (d4, n=7-9), 2,4-bis[(dodecylthio)methyl]-o-cresol (d5) (BASF Irganox® 1726), pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) (d6) (BASF lrganox®1010), triethylene glycol bis[3-(3-tert-butyl-5-methyl-4- hydroxyphenyl)propionate] (d7) (BASF lrganox®245), 2,4-bis(n-octylthio)-6-(4-hydroxy-3,5-di- tert-butylanilino)-1 ,3,5-triazine (d8) (BASF Irganox® 565), tris-(3,5-di-tert-butyl-4- hydroxybenzyl)isocyanurate (d9) (BASF lrganox®3114), 2,2-thiodiethylene bis[3-(3,5-di-tert- butyl-4-hydroxyphenyl)propionate] (d10) (BASF Irganox® 1035), 4,4’-butylidene bis-(3-methyl- 6-tert-butylphenol) (d11), octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (d12) (BASF Irganox® 1076), 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl )benzene (d13) (BASF Irganox® 1330), hexamethylene bis[3-3,5-di-tert-butyl-4- hydroxyphenyl]propionate](d14) (BASF lrganox®259) and calcium bis[monoethyl(3,5-di-tert- butyl-4-hydroxybenzyl)phosphonate] (d15) (BASF Irganox® 1425), more preferably N,N’- hexane-1,6-diyl bis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide) (d1).

Useful phosphite-based antioxidants as component (F) in the polyamide composition according to the present invention may be selected from the group consisting of diphenyl mono(2-ethylhexyl) phosphite (d16), diphenyl monotridecyl phosphite (d17), diphenyl isodecyl phosphite (d18), diphenyl isooctylphosphite (d19), diphenyl nonylphenyl phosphite (d20), triphenyl phosphite (d21), triisodecyl phosphite (d22), tris(2,4-di-tert-butylphenyl)phosphite (d23), tris(2-ethylhexyl)phosphite (d24), tetraphenyl dipropylene glycol diphosphate (d25), distearyl pentaerythritol diphosphite (d26), 2,2’-ethylidene bis(4,6-di-tert-butyl- phenol)fluorophosphate (d27), 4,4’-isopropylidene-diphenyl alkyl (C12 to C15) phosphites (d28 (n=12-15), tristearyl phosphite (d29), bis(nonylphenyl)pentaerythritol diphosphate (d30), bis(tridecyl)pentaerythritol diphosphate (d31), hydrogenated bisphenol A-pentaerythritol phosphite polymers (d32), 4,4’-butylidene bis(3-methyl-6-tert-butylphenyl-di-tridecyl phosphite) (d33), tris(nonyl-phenyl)phosphite (d34) and tris(methylphenyl) phosphite (d35), more preferably tris(2,4-di-tert-butylphenyl) phosphite (d25).

The component (F), if comprised, may be present in the polyamide composition according to the present invention in an amount of from 0.01% to 5% by weight, or from 0.2% to 2% by weight, based on the total weight of the polyamide composition. Other Components

The polyamide composition according to the present invention may optionally comprise at least one further additive, for example, lubricants, colorants other than nigrosine such as dyes and/or pigments, release agents, impact modifiers, compatibilizing agents, thermostabilizers, photostabilizers such as UV stabilizers, plasticizers, surfactants, nucleating agents, coupling agents, antimicrobial agents, antistatic agents, and any combinations thereof.

The at least one further additive, when present, may be used in conventional amounts. For example, the polyamide composition may comprise the at least one further additive in an amount of from 0.01% to 15% by weight, based on the total weight of the polyamide composition.

<Lubricant>

The polyamide composition may for example comprise a lubricant. Suitable lubricant is preferably selected from esters or amides of saturated or unsaturated aliphatic carboxylic acids having from 10 to 40, preferably from 16 to 22 carbon atoms with saturated aliphatic alcohols or amines which comprise from 2 to 40, preferably from 2 to 6 carbon atoms.

The carboxylic acids may be mono- or dibasic, for example pelargonic acid, palmitic acid, lauric acid, margaric acid, dodecanedioic acid and behenic acid, particularly stearic acid, capric acid, and also montanic acid (a mixture of fatty acids having from 30 to 40 carbon atoms).

The aliphatic alcohols may be mono- to tetrahydric, for example n-butanol, n-octanol, stearyl alcohol, ethylene glycol, propylene glycol, neopentyl glycol and pentaerythritol, preferably glycerol and pentaerythritol.

The aliphatic amines may be mono- to tri-functional, for example stearylamine, ethylenediamine, propylenediamine, hexamethylenediamine and di(6-aminohexyl) amine, preferably ethylenediamine and hexamethylenediamine.

Preferable esters or amides are N,N’-ethylene di(stearamide), glycerol distearate, glycerol tristearate, glycerol monopalmitate, glycerol trilaurate, glycerol monobehenate and pentaerythritol tetrastearate, among which N,N’-ethylene di(stearamide) is particularly preferred as a lubricant in the polyamide composition according to the present invention.

Other lubricants may be long-chain fatty acids (e.g., stearic acid or behenic acid), salts thereof (e.g., Ca stearate or Zn stearate), or montan waxes (mixtures of straight-chain, saturated carboxylic acids having chain lengths of from 28 to 32 carbon atoms), Ca montanate or Na montanate, and also low-molecular-weight polyethylene waxes and low-molecular-weight polypropylene waxes. The lubricant, if comprised, may be present in an amount of from 0.01% to 2 % by weight, or from 0.2% to 1 % by weight, based on the total weight of the polyamide composition.

<Colorant>

The polyamide composition according to the present invention may also comprise a colorant which can be inorganic pigments (e.g., TiC>2, SnC>2, ZnO, ZnS, SiC>2, etc.) and organic pigments and/or dyes such as nigrosine. Suitable colorants are known and described for example in EP 1722984 B1 , EP 1353986 B1 or DE 10054859 A1.

The colorant, if comprised, may be present in an amount of from 0.01 % to 15% by weight, or from 1 % to 15% by weight, or from 2% to 8% by weight, based on the total weight of the polyamide composition.

<lmpact Modifier>

The polyamide composition according to the present invention may also for example comprise an impact modifier. Suitable impact modifiers may include polyolefin-based, styrene-based, unsaturated carboxylic acid-based impact modifiers, and also those modified by a functional block, such as epoxy functional block and/or acid anhydride block. The epoxy function block may be units derived from a glycidyl (meth)acrylate. The acid anhydride block may be units derived from maleic anhydride.

Suitable polyolefin-based impact modifiers may include polyolefins comprising repeating units derived from olefin having from 2 to 10 carbon atoms. Examples of such olefins include ethene, 1-butene, 1-propene, 1-pentene, 1-octene and a mixture of ethene and 1-octene, preferably ethene, 1-propene and a mixture of ethene and 1-octene.

Suitable unsaturated carboxylic acid-based impact modifiers may include blocks derived from carboxylic acid and derivates thereof such as ester, imide and amide. Suitable carboxylic acids and derivates thereof are for example acrylic acid, acrylic acid, methacrylic acid, maleic acid, fumaric acid, glutaconic acid, itaconic acid, citraconic acid, (meth)acrylate, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (methyl)acrylate and isobutyl (meth)acrylate.

The impact modifier may also be a bi- or ter-polymer or a core-shell structure polymer. Examples of such impact modifiers include styrene/ethene/butene copolymer (SEBS), ethenemethyl acrylate-glycidyl methacrylate terpolymer, ethene/propene/diene rubber (EPDM) and ethene-octene copolymer.

The impact modifier, if comprised, may be present in an amount of from 0.01 % to 15% by weight, or from 1 to 15% by weight, or from 5 to 10% by weight, based on the total weight of the polyamide composition. <Plasticizer>

The polyamide composition according to the present invention may also for example comprise a plasticizer, including but are not limited to dioctyl phthalate, dibenzyl phthalate, butyl benzyl phthalate, hydrocarbon oils and N-(n-butyl) benzenesulfonamide.

The plasticizer, if comprised, may be present in an amount of from 0.01% to 15% by weight, or from 1% to 15% by weight, or from 5% to 10% by weight, based on the total weight of the polyamide composition.

In some embodiments, the polyamide composition according to the present invention does not comprise a polyol or polyol ether, for example glycerol, dipentaerythritol, triipentaerythritol, trimethylolethane, trimethylolpropane, di(trimethylolpropane), trimethylolpropane triglycidyl ether, D-mannitol, D-sorbitol, xylitol and arabitol.

Formulations

In some exemplary embodiments, the polyamide composition according to the present invention comprises

- from 10% to 65% by weight of a polyamide as component (A), which has repeating units of formula (I): o

-+NH-R ¹ -C - _(|)J in which

R ¹ is a hydrocarbylene group, preferably an alkylene group, having from 5 to 17 carbon atoms, more preferably from 5 to 11 carbon atoms,

- from 5% to 45% by weight of a polyketone as component (B), which has a weight average molecular weight (Mw) in the range of 80,000 to 250,000,

- from 10% to 25% by weight of a phosphorus based flame retardant, a halogen based flame retardant or a combination thereof as component (C), and

- from 5% to 50% by weight of a reinforcing agent selected from glass fibers as component (D), each being based on the total weight of the polyamide composition.

In some other exemplary embodiments, the polyamide composition according to the present invention comprises

- from 10% to 40% by weight of a polyamide as component (A), which has repeating units of formula (I): o

-+NH-R ¹ -C - _(|)J in which

R ¹ is a hydrocarbylene group, preferably an alkylene group, having from 5 to 17 carbon atoms, more preferably from 5 to 11 carbon atoms, - from 5% to 40% by weight of a polyketone as component (B), which has a weight average molecular weight (Mw) in the range of 100,000 to 200,000,

- from 10% to 25% by weight of a phosphorus based flame retardant, a halogen based flame retardant or a combination thereof as component (C), wherein the phosphorus based flame retardant is selected from metal organophosphinates or a combination of a metal salt of phosphoric acid or phosphorous acid with a metal salt of phosphinate, the halogen based flame retardant is selected from brominated compounds,

- from 10 % to 40% by weight of a reinforcing agent selected from glass fibers as component (D), each being based on the total weight of the polyamide composition.

In some further exemplary embodiments, the polyamide composition according to the present invention comprises

- from 20% to 40% by weight of a polyamide as component (A), which has repeating units of formula (I): o

-+NH-R ¹ -C - _(|)J in which

R ¹ is a hydrocarbylene group, preferably an alkylene group, having from 5 to 17 carbon atoms, more preferably from 5 to 11 carbon atoms,

- from 8% to 30% by weight of a polyketone as component (B), which has a weight average molecular weight (Mw) in the range of 100,000 to 200,000,

- from 15% to 25% by weight of a phosphorus based flame retardant or a halogen based flame retardant as component (C), wherein the phosphorus based flame retardant is selected from metal organophosphinates or a combination of a metal salt of phosphoric acid or phosphorous acid with a metal salt of phosphinate, the halogen based flame retardant is selected from brominated polystyrenes,

- from 20 % to 40% by weight of a reinforcing agent selected from glass fibers as component (D), each being based on the total weight of the polyamide composition.

In some particular exemplary embodiments, the polyamide composition according to the present invention comprises

- from 20% to 40% by weight of a polyamide as component (A), which has repeating units of formula (I): o

-+NH-R ¹ -C - _(|)J in which

R ¹ is a hydrocarbylene group, preferably an alkylene group, having from 5 to 17 carbon atoms, more preferably from 5 to 11 carbon atoms,

- from 8% to 30% by weight of a polyketone as component (B), which has a weight average molecular weight (Mw) in the range of 100,000 to 150,000,

- from 15% to 25% by weight of a phosphorus based flame retardant or a halogen based flame retardant as component (C), wherein the phosphorus based flame retardant is selected from metal organophosphinates or a combination of a metal salt of phosphoric acid or phosphorous acid with a metal dialkylphosphinate, the halogen based flame retardant is selected from brominated polystyrenes,

- from 20 % to 40% by weight of a reinforcing agent selected from glass fibers as component (D), each being based on the total weight of the polyamide composition.

In any of the above exemplary embodiments, the polyamide composition according to the present invention optionally comprises one or more of following components,

- from 1 % to 15 % by weight, or from 3 % to 9 % by weight of a flame retardant synergist,

- from 0.01% to 5% by weight, or from 0.2% to 2% by weight of an antioxidant, and

- from 0.01 % to 2 % by weight, or from 0.2% to 1 % by weight of a lubricant, each being based on the total weight of the polyamide composition.

In any of the above exemplary embodiments, the antioxidant is selected from hindered phenol- based antioxidants, phosphite-based antioxidants, or a combination thereof.

In any of the above exemplary embodiments, the polyamide composition comprises no polyol, for example glycerol, dipentaerythritol, triipentaerythritol, trimethylolethane, trimethylolpropane, di(trimethylolpropane), trimethylolpropane triglycidyl ether, D-mannitol, D-sorbitol, xylitol and arabitol.

Articles

The polyamide composition according to the present invention may be processed into various structures or forms by conventional methods. For example, individual components of the polyamide composition according to the present invention may be mixed and then molded, for example via injection and/or extrusion in a conventional apparatus such as a screw extruder, a Brabender mixer or a Banbury mixer to form articles. The mixing is generally carried out at a temperature sufficient to keep polymeric components as a molten medium in the range of from 220 °C to 260 °C.

It will be understood that all components of the polyamide composition may be mixed at the same time. Alternatively, some components of the polyamide composition may be pre-mixed and then mixed with other components. For example, non-polymeric components of composition may be added at any point during processing, in particular by hot or cold blending with the polymer matrix.

Accordingly, the present invention provides an article produced from the polyamide composition according to the present invention.

The polyamide composition according to the present invention has good mechanical properties, especially improved toughness, and may also have a good long-term heat resistance. Thus, the article produced from the polyamide composition according to the present invention can be used in many fields, including but being not limited to, automobile parts which has a requirement of long-term heat resistance over 120 °C. The automobile parts could be engine parts, chassis parts, crossbeam parts of any type, etc.

Embodiments

Various embodiments are listed below. It will be understood that the embodiments listed below can be combined with all aspects and other embodiments in accordance with the scope of the invention.

1. A polyamide composition, which comprises

- from 10% to 65% by weight of a polyamide as component (A),

- from 5% to 45% by weight of a polyketone as component (B), which has a weight average molecular weight (Mw) in the range of 80,000 to 250,000,

- from 10% to 25% by weight of a flame retardant as component (C), and

- from 5% to 50% by weight of a reinforcing agent as component (D), each being based on the total weight of the polyamide composition.

2. The polyamide composition according to Embodiment 1 , wherein the polyketone has a weight average molecular weight (Mw) in the range of 80,000 to 250,000.

3. The polyamide composition according to Embodiment 2, wherein the polyketone has a weight average molecular weight (Mw) in the range of 100,000 to 200,000.

4. The polyamide composition according to Embodiment 3, wherein the polyketone has a weight average molecular weight (Mw) in the range of 100,000 to 150,000.

5. The polyamide composition according to any of preceding Embodiments, wherein the polyketone has an intrinsic viscosity (IV) of from 0.8 to 1.8 dL/g.

6. The polyamide composition according to Embodiment 5, wherein the polyketone has an intrinsic viscosity (IV) of from 0.8 to 1.6 dL/g.

7. The polyamide composition according to any of preceding Embodiments, wherein the component (A) is present in an amount of from 10% to 40% by weight.

8. The polyamide composition according to Embodiment 7, wherein the component (A) is present in an amount of from 20% to 40% by weight.

9. The polyamide composition according to any of preceding Embodiments, wherein the component (B) is present in an amount of from 5% to 40% by weight.

10. The polyamide composition according to Embodiment 9, wherein the component (B) is present in an amount of from 8 % to 30% by weight. 11. The polyamide composition according to any of preceding Embodiments, wherein the flame retardant is phosphorus based flame retardants, halogen based flame retardants, or a combination thereof.

12. The polyamide composition according to Embodiment 11 , wherein the phosphorus based flame retardant is selected from metal organophosphinates or a combination of a metal salt of phosphoric acid or phosphorous acid with a metal salt of phosphinate, and wherein the halogen based flame retardant is selected from brominated compounds.

13. The polyamide composition according to any of preceding Embodiments, wherein the component (C) is present in an amount of from 15 % to 25 % by weight.

14. The polyamide composition according to any of preceding Embodiments, wherein the reinforcing agent is selected from glass fibers.

15. The polyamide composition according to any of preceding Embodiments, wherein the component (D) is present in an amount of from 10 % to 40% by weight.

16. The polyamide composition according to Embodiment 15, wherein the component (D) is present in an amount of from 20% to 40% by weight.

17. The polyamide composition according to any of preceding Embodiments, wherein the polyamide composition further comprises one or more of following components,

- from 1 % to 15% by weight, or from 3 % to 9 % by weight of a flame retardant synergist,

- from 0.01% to 5% by weight, or from 0.2% to 2% by weight of an antioxidant, and

- from 0.01% to 2 % by weight, or from 0.2% to 1 % by weight of a lubricant, each being based on the total weight of the polyamide composition.

18. The polyamide composition according to any of peceding Embodiments, wherein the polyamide as component (A) has repeating units of formula (I): wherein

R ¹ is a hydrocarbylene group, preferably an alkylene group, having from 3 to 29 carbon atoms, preferably from 5 to 17 carbon atoms, more preferably from 5 to 11 carbon atoms.

19. The polyamide composition according to Embodiment 18, wherein the polyamide is polyamide 6.

20. The polyamide composition according to any of preceding Embodiments, which is free of glycerol, dipentaerythritol, triipentaerythritol, trimethylolethane, trimethylolpropane, di(trimethylolpropane), trimethylolpropane triglycidyl ether, D-mannitol, D-sorbitol, xylitol and arabitol. 21 . The polyamide composition according to any of preceding Embodiments, which comprises no polyol.

22. An article, especially automobile part, obtained or obtainable from the polyamide composition according to any of Embodiments 1 to 21.

EXAMPLES

Aspects of the present invention are more fully illustrated by the following examples, which are set forth to illustrate certain aspects of the present invention and are not to be construed as limiting thereof.

Materials

Materials as used in Examples were summarized in Table 1.

Table 1

Measurements

1. Tensile strength, tensile modulus and elongation at break were measured according to ISO 527-1-2012. Test specimens of type 1 having thickness of 4 mm as described in ISO 527-1- 2012 were used. Charpy notched impact strength and Charpy unnotched impact strength were measured according to ISO 179-1-2010 via edgewise impact. Test specimens for Charpy unnotched test is type 1 specimen with the dimensions of 80 x 10 x 4mm (length x width x thickness). Test specimens for Charpy notched test are type 1 with notched type A. The test specimens were pretreated in air under a humidity of 50% at 23 °C for 16 hours.

2. Flame retardancy was determined by the UL 94V method (Underwriters Laboratories Inc. Standard of Safety, “Test for Flammability of Plastic Materials for Parts in Devices and Appliances”, p.14 to p. 18, Northbrook 1998). Test specimens were sheets having a size of 127 mm x 12.7 mm x 0.80 mm (or 1.50 mm) (length x width x thickness).

3. Comparative test index (CTI) value was measured according to IEC 60112, which provides a quantitative indication for the electrical breakdown ability of an electrical-insulation material under wet and/or contaminated environment.

4. Glow-wire resistance GWIT (glow-wire ignition temperature) was tested in accordance with IEC 60695-2-13 on plaques, which is a general suitability test for plastics in contact with parts that carry an electrical potential.

The test specimens used were made according to the following general procedure for preparing the test specimens.

General procedure for preparing the test specimens

Test specimens were prepared in accordance with the formulations as shown in following Tables. All raw materials except the glass fiber were mixed together in a Tubula T50A highspeed stirrer and fed into a Coperion ZSK18 MC twin-screw extruder at the throat, and the glass fiber was fed at downstream using a side feeder, then melt-extruded under a temperature of 250°C, and pelletized and dried at a temperature of 80 °C for 4 hours, thus obtaining dried pellets.

The dried pellets were then processed in an injection molding machine (Haitian MA900 II) with a clamping force of 900 kN at a melt temperature of 245 °C and a molding temperature of 50 °C to provide a test specimen.

The obtained test specimens were measured for the properties as described above. The test results and the formulations for the preparation of the test specimens are summarized in following Tables. Table 2 n.a.: Not possible to prepare due to high viscosity

Table 3

It was suprisingly found that the blends of PA6 with POK contaning a phosphorus based flame retardant exhibited a synergistic flowability improvement. As shown by the spiral flow length data, the flowability of the blends of PA6 with POK is higher than that of PA6 alone and POK alone.

Table 4

The synergistic flowability improvement in the blends of PA6 with POK M930A was also obserbed when halogen based flame retardant was used in the blends.

It will be apparent to one of ordinary skill in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the present invention. It is intended that the embodiments and examples be considered as exemplary only. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.