POLYMER COMPOSITION COMPRISING POLYCARBONATE AND ABS WITH IMPROVED HEAT AGEING AND SURFACE APPEARANCE PROPERTIES

Abstract

The invention relates to a process for the preparation of a final heterophasic propylene copolymer (A) having a final melt flow rate in the range from 65 to 110 dg/min, comprising visbreaking an intermediate heterophasic propylene copolymer (A) having an intermediate melt flow rate, which intermediate melt flow rate is lower than the final melt flow rate, to obtain the final heterophasic propylene copolymer, wherein the intermediate heterophasic propylene copolymer (A) consists of (a) a propylene-based matrix, (b) a dispersed ethylene--olefin copolymer, wherein the sum of the total amount of propylene-based matrix and total amount of the dispersed ethylene--olefin copolymer in the intermediate heterophasic propylene copolymer is 100 wt % based on the intermediate heterophasic propylene copolymer.

Claims

1. A process for the preparation of a final heterophasic propylene copolymer (A) having a final melt flow rate in the range from 65 to 110 dg/min as measured according to ISO1133 at 230 C. and 2.16 kg, comprising: visbreaking an intermediate heterophasic propylene copolymer (A) having an intermediate melt flow rate, which intermediate melt flow rate is lower than the final melt flow rate, to obtain the final heterophasic propylene copolymer, wherein the intermediate heterophasic propylene copolymer (A) consists of (a) a propylene-based matrix, wherein the propylene-based matrix consists of a propylene homopolymer, wherein the melt flow rate of the propylene-based matrix is in the range from 75 to 85 dg/min as measured according to ISO1133 at 230 C. and 2.16 kg, (b) a dispersed ethylene--olefin copolymer, wherein the amount of ethylene incorporated into the ethylene--olefin copolymer is in the range from 45 to 55 wt % based on the ethylene--olefin copolymer, wherein the amount of ethylene--olefin copolymer is less than 15 wt % and at least 10 wt % based on the intermediate heterophasic propylene copolymer, wherein the melt flow rate of the ethylene--olefin copolymer is in the range from 0.50 to 2.0 dg/min as calculated using the following formula: $\mathrm{MFREPR}=10^\left(\frac{\mathrm{Log}.Math..Math.\mathrm{MFR}.Math..Math.\mathrm{heterophasic}-\mathrm{matrix}.Math..Math.\mathrm{content}*\mathrm{Log}.Math..Math.\mathrm{MFR}.Math..Math.\mathrm{PP}}{\mathrm{rubber}.Math..Math.\mathrm{content}}\right)$ wherein MFR heterophasic is the melt flow rate of the intermediate heterophasic propylene copolymer measured according to ISO1133 (2.16 kg/230 C.), MFR PP is the MFR of the propylene-based matrix of the intermediate heterophasic propylene copolymer measured according to IS01133 (2.16 kg/230 C.), matrix content is the amount of the propylene-based matrix in the intermediate heterophasic propylene copolymer, and rubber content is the amount of the dispersed ethylene--olefin copolymer in the intermediate heterophasic propylene copolymer, wherein the sum of the total amount of propylene-based matrix and total amount of the dispersed ethylene--olefin copolymer in the intermediate heterophasic propylene copolymer is 100 wt % based on the intermediate heterophasic propylene copolymer.

2. The process according to claim 1, wherein the intermediate heterophasic propylene copolymer is prepared using a phthalate-free catalyst, wherein the phthalate-free catalyst has a phthalate content of less than for example 150 ppm, based on the total weight of the catalyst.

3. The process according to claim 1, wherein the intermediate heterophasic propylene copolymer is prepared from propylene, ethylene and optionally another -olefin by contacting propylene, ethylene and optionally another -olefin in the presence of a catalyst composition to obtain the intermediate heterophasic propylene copolymer, wherein said catalyst composition is prepared by combined a procatalyst with a co-catalyst and optionally at least one external donor to form the catalyst composition, wherein the procatalyst is prepared by a process comprising the steps of providing a magnesium-based support, contacting said magnesium-based support with a Ziegler-Natta type catalytic species, an internal donor, and an activator, to yield a procatalyst, wherein the activator is a benzamide according to formula X: ##STR00002## wherein R.sup.70 and R.sup.71 are each independently selected from hydrogen or an alkyl, and R.sup.72, R.sup.73, R.sup.74, R.sup.75, R.sup.76 are each independently selected from hydrogen, a heteroatom or a hydrocarbyl group, and one or more combinations thereof; and wherein the internal donor is selected from the group consisting of 1,3-diethers represented by the Formula VII, ##STR00003## wherein R.sup.51 and R.sup.52 are each independently selected from a hydrogen or a hydrocarbyl group selected from alkyl, alkenyl, aryl, aralkyl, alkoxycarbonyl or alkylaryl groups, and one or more combinations thereof, and wherein R.sup.53 and R.sup.54 are each independently selected from a hydrocarbyl group.

4. The process according to claim 1, wherein the -olefin in the ethylene--olefin copolymer is propylene.

5. The process according to claim 1, the propylene-based matrix of the intermediate heterophasic propylene copolymer has a molecular weight distribution (M.sub.w/M.sub.n) in the range from 4.0 to 5.5, wherein Mw stands for the weight average molecular weight and Mn stands for the number average molecular weight are measured by SEC analysis.

6. The process according to claim 1, wherein the final heterophasic propylene copolymer shows an emission of less than 1800 mg/kg, as determined by isopropanol extraction and analysis of the extract using PTV-GC-MS.

7. The process according to claim 1, wherein the shifting ratio, which is the ratio of the final melt flow rate to the intermediate melt flow rate is in the range from 1.3 to 2.5.

8. A heterophasic propylene copolymer (A) obtained by the process of claim 1.

9. The heterophasic propylene copolymer according to claim 8, wherein the impact strength of the final heterophasic propylene copolymer (A) is at least 3.5 kJ/m.sup.2 as determined at 23 C. according to ISO 180 4A.

10. A composition comprising the heterophasic propylene copolymer (A) of claim 8.

11. The composition according to claim 10, further comprising a nucleating composition (B), wherein (B) the nucleating composition comprises (i) a first nucleating agent, which comprises a cyclic dicarboxylate salt compound; and (ii) a second nucleating agent, which comprises talc, wherein the cyclic dicarboxylate salt compound has the formula (I): ##STR00004##

12. The composition according to claim 11, having a flexural modulus of at least 1600 MPa, as determined at 23 C. in parallel and/or perpendicular direction, according to ASTM D790 Procedure B on a sample of 6512.73.2 mm.

13. An article comprising the heterophasic propylene copolymer of claim.

14. The article according to claim 13, wherein the article is an injection molded article.

15. The process according to claim 1, wherein R.sup.53 and R.sup.54 are each independently selected from alkyl, alkenyl, aryl, aralkyl, alkoxycarbonyl or alkylaryl groups, and one or more combinations thereof.

16. The process according to claim 6, wherein the final heterophasic propylene copolymer shows an emission of less than 1700 mg/kg heterophasic propylene copolymer as determined by isopropanol extraction and analysis of the extract using PTV-GC-MS.

17. The process according to claim 1, wherein the intermediate heterophasic propylene copolymer is prepared using a phthalate-free catalyst, wherein the phthalate-free catalyst has a phthalate content of less than 100 ppm, based on the total weight of the catalyst; the propylene-based matrix of the intermediate heterophasic propylene copolymer has a molecular weight distribution (M.sub.w/M.sub.n) in the range from 4.0 to 5.5, wherein Mw stands for the weight average molecular weight and Mn stands for the number average molecular weight are measured by SEC analysis; wherein the final heterophasic propylene copolymer shows an emission of less than 1600 mg/kg heterophasic propylene copolymer, as determined by isopropanol extraction and analysis of the extract using PTV-GC-MS; and wherein the shifting ratio, which is the ratio of the final melt flow rate to the intermediate melt flow rate is in the range from 1.5 to 2.2.

18. The process according to claim 17, wherein the intermediate heterophasic propylene copolymer is prepared from propylene, ethylene and another -olefin by contacting the propylene, the ethylene and the another -olefin in the presence of a catalyst composition to obtain the intermediate heterophasic propylene copolymer, wherein said catalyst composition is prepared by combining a procatalyst with a co-catalyst and at least one external donor to form the catalyst composition, wherein the procatalyst is prepared by a process comprising the steps of providing a magnesium-based support, contacting said magnesium-based support with a Ziegler-Natta type catalytic species, an internal donor, and an activator, to yield a procatalyst, wherein the activator is a benzamide according to formula X: ##STR00005## wherein R.sup.70 and R.sup.71 are each independently selected from hydrogen or an alkyl, and R.sup.72, R.sup.73, R.sup.74, R.sup.75, R.sup.76 are each independently selected from hydrogen, a heteroatom or a hydrocarbyl group, and one or more combinations thereof; and wherein the internal donor is selected from the group consisting of 1,3-diethers represented by the Formula VII, ##STR00006## wherein R.sup.51 and R.sup.52 are each independently selected from a hydrogen or a hydrocarbyl group selected from alkyl, alkenyl, aryl, aralkyl, alkoxycarbonyl or alkylaryl groups, and one or more combinations thereof, and wherein R.sup.53 and R.sup.54 are each independently selected from a hydrocarbyl group.

Description

[0006] The above clearly presents that there is a desire to obtain polymer compositions comprising polycarbonate and ABS that do provide the desired properties with regard to part quality and processability via injection moulding, but which show an improved quality of the surface area of parts produced via injection moulding.

[0007] This has now been achieved according to the present invention by a polymer composition comprising: [0008] polycarbonate; [0009] acrylonitrile-butadiene-styrene copolymer; and [0010] 0.001 and 0.500 wt % of a phosphate salt of zinc, sodium, calcium, potassium or magnesium, with regard to the total weight of the polymer composition.

[0011] Such polymer composition demonstrates a reduction of surface defects in the form of silver streaks, whereas further demonstrating a desired balance of mechanical properties, thermal properties and processing properties. Further, such polymer composition demonstrates a particularly low decrease of the weight average molecular weight upon lengthy exposure to temperatures above the melting temperature of the polymer components of the composition, such as a temperature of 300 C. or above.

[0012] The polymer composition according to the present invention comprises polycarbonate. Polycarbonate in the context of the present invention may for example relate to polymers or mixtures of polymers comprising polymeric units according to the formula I:

##STR00001##

[0013] wherein R1 is a moiety comprising at least one aromatic ring. Preferably, at least 60% of the polymeric units in the polycarbonate are units according to formula I. More preferably, at least 80% of the polymeric units in the polycarbonate are units according to formula I. Even more preferably, at least 90%, or at least 95%, or at least 98% of the polymeric units in the polycarbonate are units according to formula I. In a particular embodiment, the polycarbonate is a homopolymer comprising repeating units according to formula I.

[0014] In a particular embodiment, R1 is a moiety having a molecular formula R2-R3-R2, wherein each R2 individually is a monocyclic divalent aryl moiety and R3 is a bridging moiety wherein each R2 is bound to the same atom of moiety R3. For example, R3 may be a hydrocarbon moiety, for example a hydrocarbon moiety comprising 1-10 carbon atoms. In a particular embodiment, R3 is a moiety selected from methylene, cyclohexylidene or isopropylidene.

[0015] It is particularly preferred that each R2 is phenyl and R3 is isopropylidene.

[0016] The polycarbonate that may be used in the polymer composition according to the present invention may for example be produced via interfacial polymerisation processes or via bulk polymerisation processes. The polycarbonate preferably comprises polymeric units comprising moieties derived from 2,2-bis(4-hydroxyphenyl)propane. Preferably, the moieties R1 according to formula I are moieties derived from 2,2-bis(4-hydroxyphenyl)propane.

[0017] The polycarbonate may for example have a weight average molecular weight of 20000 g/mol, preferably 25000 g/mol, more preferably 30000 g/mol, more preferably 35000 g/mol, more preferably 40000 g/mol. The polycarbonate may for example have a molecular weight of 100000 g/mol, preferably 80000 g/mol, more preferably 70000 g/mol, more preferably 60000 g/mol. The polycarbonate may for example have a weight average molecular weight of 20000 and 100000 g/mol, preferably 25000 and 80000 g/mol, more preferably 30000 and 80000 g/mol, more preferably 35000 and 70000 g/mol, more preferably 40000 and 60000 g/mol. Such polycarbonate provides desirable processing properties combined with desirable properties of the moulded product.

[0018] The polycarbonate that is used in the polymer composition according to the present invention is in a particular embodiment a mixture comprising a first polycarbonate and a second polycarbonate. It is preferred that the first polycarbonate has a different weight average molecular weight than the second polycarbonate. It is preferred that the first polycarbonate has a lower weight average molecular weight than the second polycarbonate. This first polycarbonate may for example have a weight average molecular weight of 20000 and <50000 g/mol, preferably 30000 and 45000 g/mol, more preferably 35000 and 42000 g/mol. The second polycarbonate may for example have a weight average molecular weight of 50000 g/mol and 100000 g/mol, preferably 50000 and 80000 g/mol, more preferably 52000 and 60000 g/mol. It is particularly preferred that the polycarbonate is a mixture comprising a first polycarbonate and a second polycarbonate, wherein the first polycarbonate has a weight average molecular weight of 20000 and <50000 g/mol and wherein the second polycarbonate has a weight average molecular weight of 50000 g/mol and 100000 g/mol. It is further is particularly preferred that the polycarbonate is a mixture comprising a first polycarbonate and a second polycarbonate, wherein the first polycarbonate has a weight average molecular weight of 30000 and <45000 g/mol and wherein the second polycarbonate has a weight average molecular weight of 50000 g/mol and 70000 g/mol. Alternatively, the polycarbonate may be a mixture comprising a first polycarbonate and a second polycarbonate, the first polycarbonate having a weight average molecular weight of less than 45000 g/mol, and second polycarbonate having a weight average molecular weight of at least 50000 g/mol.

[0019] The weight average molecular weight M.sub.w may for example be determined using size-exclusion chromatography using polycarbonate standards, such as for example via the method of ISO 16014-1 (2012).

[0020] It is preferred that the polymer composition according to the present invention comprises 30.0 wt % of polycarbonate, more preferably 40.0 wt %, more preferably 50.0 wt %, more preferably 60.0 wt %, more preferably 70.0 wt %, with regard to the total weight of the polymer composition. It is preferred that the polymer composition comprises 95.0 wt % of polycarbonate, more preferably 90.0 wt %, more preferably 85.0 wt %, more preferably 80.0 wt %, with regard to the total weight of the polymer composition.

[0021] It is particularly preferred that the polymer composition comprises 30.0 wt % and 95.0 wt % of polycarbonate, more preferably 50.0 wt % and 90.0 wt %, more preferably 60.0 wt % and 85.0 wt %, with regard to the total weight of the polymer composition.

[0022] In the embodiment of the invention where the polycarbonate is a mixture of a first polycarbonate and a second polycarbonate, the polymer composition comprises 10.0 wt % of the first polycarbonate and 10.0 wt % of the second polycarbonate, with regard to the total weight of the polymer composition. More preferably, the polymer composition comprises 20.0 wt % of the first polycarbonate and 20.0 wt % of the second polycarbonate, with regard to the total weight of the polymer composition. Even more preferably, the polymer composition comprises 30.0 wt % of the first polycarbonate and 30 wt % of the second polycarbonate, with regard to the total weight of the polymer composition.

[0023] Preferably, the polymer composition comprises 45.0 wt % of the first polycarbonate and 45.0 wt % of the second polycarbonate, with regard to the total weight of the polymer composition. More preferably, the polymer composition comprises 40.0 wt % of the first polycarbonate and 40.0 wt % of the second polycarbonate, with regard to the total weight of the polymer composition.

[0024] Particularly preferably, the polymer composition comprises 10.0 and 45.0 wt % of the first polycarbonate, and 10.0 and 45.0 wt % of the second polycarbonate, with regard to the total weight of the polymer composition. More preferably, the polymer composition comprises 30.0 and 40.0 wt % of the first polycarbonate, and 30.0 and 40.0 wt % of the second polycarbonate, with regard to the total weight of the polymer composition.

[0025] Further particularly preferably, the polymer composition comprises 10.0 and 45.0 wt % of the first polycarbonate, and 10.0 and 45.0 wt % of the second polycarbonate, with regard to the total weight of the polymer composition, wherein the first polycarbonate has a weight average molecular weight of 20000 and <50000 g/mol and wherein the second polycarbonate has a weight average molecular weight of 50000 g/mol and 100000 g/mol. More preferably, the polymer composition comprises 30.0 and 40.0 wt % of the first polycarbonate, and 30.0 and 40.0 wt % of the second polycarbonate, with regard to the total weight of the polymer composition, wherein the first polycarbonate has a weight average molecular weight of 30000 and <45000 g/mol and wherein the second polycarbonate has a weight average molecular weight of 50000 g/mol and 70000 g/mol.

[0026] It is particularly preferred that where the polycarbonate is a mixture of a first polycarbonate and a second polycarbonate, one of the first polycarbonate and the second polycarbonate is produced via interfacial polymerisation. It is further particularly preferred that where the polycarbonate is a mixture of a first polycarbonate and a second polycarbonate, one of the first polycarbonate and the second polycarbonate is produced via melt polymerisation. It is particularly preferred that where the polycarbonate is a mixture of a first polycarbonate and a second polycarbonate, one of the first polycarbonate and the second polycarbonate is produced via interfacial polymerisation and the other of the first polycarbonate and the second polycarbonate is produced via melt polymerisation.

[0027] Even further particularly, it is preferred that where the polycarbonate is a mixture of a first polycarbonate and a second polycarbonate, the first polycarbonate has a lower weight average molecular weight than the second polycarbonate, and the first polycarbonate is produced via interfacial polymerisation. It is also particularly preferred that where the polycarbonate is a mixture of a first polycarbonate and a second polycarbonate, the first polycarbonate has a lower weight average molecular weight than the second polycarbonate, and the second polycarbonate is produced via melt polymerisation. It is even further particularly preferred that where the polycarbonate is a mixture of a first polycarbonate and a second polycarbonate, the first polycarbonate has a lower molecular weight than the second polycarbonate, the first polycarbonate is produced via interfacial polymerisation, and the second polycarbonate is produced via melt polymerisation.

[0028] In particular, where the polycarbonate is a mixture of a first polycarbonate and a second polycarbonate, it is preferred that the first polycarbonate is produced via interfacial polymerisation and the second polycarbonate is produced via melt polymerisation, wherein the polymer composition comprises 10.0 and 45.0 wt % of the first polycarbonate, and 10.0 and 45.0 wt % of the second polycarbonate, with regard to the total weight of the polymer composition. Further particularly, where the polycarbonate is a mixture of a first polycarbonate and a second polycarbonate, it is preferred that the first polycarbonate is produced via interfacial polymerisation and the second polycarbonate is produced via melt polymerisation, wherein the polymer composition comprises 30.0 and 40.0 wt % of the first polycarbonate, and 30.0 and 40.0 wt % of the second polycarbonate, with regard to the total weight of the polymer composition.

[0029] Even further particularly, where the polycarbonate is a mixture of a first polycarbonate and a second polycarbonate, it is preferred that the first polycarbonate is produced via interfacial polymerisation and the second polycarbonate is produced via melt polymerisation, wherein the polymer composition comprises 10.0 and 45.0 wt % of the first polycarbonate, and 10.0 and 45.0 wt % of the second polycarbonate, with regard to the total weight of the polymer composition, the first polycarbonate has a weight average molecular weight of 20000 and <50000 g/mol and wherein the second polycarbonate has a weight average molecular weight of 50000 g/mol and 100000 g/mol. More further particularly, where the polycarbonate is a mixture of a first polycarbonate and a second polycarbonate, it is preferred that the first polycarbonate is produced via interfacial polymerisation and the second polycarbonate is produced via melt polymerisation, wherein the polymer composition comprises 30.0 and 40.0 wt % of the first polycarbonate, and 30.0 and 40.0 wt % of the second polycarbonate, with regard to the total weight of the polymer composition, the first polycarbonate has a weight average molecular weight of 30000 and <45000 g/mol and wherein the second polycarbonate has a weight average molecular weight of 50000 g/mol and 70000 g/mol.

[0030] The polymer composition according to the present invention comprises acrylonitrile-butadiene-styrene copolymer. The acrylonitrile-butadiene-styrene copolymer is also referred to as ABS.

[0031] The polymer composition according to the present invention may for example comprise 5.0 wt %, preferably 10.0 wt %, more preferably 15.0 wt %, or even more preferably 20.0 wt % of the acrylonitrile-butadiene-styrene copolymer, with regard to the total weight of the polymer composition.

[0032] The polymer composition according to the present invention may for example comprise 80.0 wt %, preferably 60.0 wt %, more preferably 50.0 wt %, or even more preferably 40.0 wt % of the acrylonitrile-butadiene-styrene copolymer, with regard to the total weight of the polymer composition.

[0033] Preferably, the polymer composition according to the present invention comprises 5.0 and 80.0 wt %, preferably 10.0 and 60.0 wt %, more preferably 20.0 and 40.0 wt % of the acrylonitrile-butadiene-styrene copolymer, with regard to the total weight of the polymer composition.

[0034] The ABS may for example be a copolymer comprising polymeric units comprising moieties derived from acrylonitrile, moieties derived from 1,3-butadiene and moieties derived from styrene. The ABS may for example be a copolymer comprising 10.0 wt % and 70.0 wt % of moieties derived from 1,3-butadiene, with regard to the total weight of the ABS. Preferably, ABS may is a copolymer comprising 20.0 wt % and 60.0 wt %, more preferably 30.0 wt % and 50.0 wt % of moieties derived from 1,3-butadiene, with regard to the total weight of the ABS.

[0035] In a particular embodiment, the ABS comprises a mixture of a first copolymer and a second copolymer. The first copolymer may be a copolymer comprising polymeric units comprising moieties derived from acrylonitrile, moieties derived from 1,3-butadiene and moieties derived from styrene. The second copolymer may be a copolymer comprising polymeric units comprising moieties derived from acrylonitrile and moieties derived from styrene.

[0036] In the embodiment of the invention where the ABS is a mixture comprising a first copolymer and a second copolymer, where first copolymer is a copolymer comprising polymeric units comprising moieties derived from acrylonitrile, moieties derived from 1,3-butadiene and moieties derived from styrene and the second copolymer is a copolymer comprising polymeric units comprising moieties derived from acrylonitrile and moieties derived from styrene, it is preferred that the first copolymer comprises 40.0 wt % and 70.0 wt %, more preferably 40.0 and 60.0 wt %, of moieties derived from 1,3-butadiene, with regard to the total weight of the first copolymer.

[0037] In a particular embodiment of the invention, the ABS is a mixture comprising a first copolymer and a second copolymer, wherein the first copolymer comprises moieties derived from acrylonitrile, moieties derived from 1,3-butadiene and moieties derived from styrene, and the second copolymer comprises polymeric units comprising moieties derived from acrylonitrile and moieties derived from styrene.

[0038] Preferably, the ABS is a mixture comprising a first copolymer and a second copolymer, wherein the first copolymer comprises moieties derived from acrylonitrile, moieties derived from 1,3-butadiene and moieties derived from styrene, and the second copolymer comprises polymeric units comprising moieties derived from acrylonitrile and moieties derived from styrene, wherein the second copolymer does not comprise moieties derived from 1,3-butadiene.

[0039] More preferably, the ABS is a mixture comprising a first copolymer and a second copolymer, wherein the first copolymer comprises moieties derived from acrylonitrile, moieties derived from 1,3-butadiene and moieties derived from styrene, and the second copolymer consists of polymeric units comprising moieties derived from acrylonitrile and moieties derived from styrene.

[0040] Further preferably, the ABS is a mixture comprising a first copolymer and a second copolymer, wherein the first copolymer comprises moieties derived from acrylonitrile, moieties derived from 1,3-butadiene and moieties derived from styrene, and the second copolymer comprises polymeric units comprising moieties derived from acrylonitrile and moieties derived from styrene, wherein the polymer composition comprises 15.0 wt % of the second copolymer, with regard to the total weight of the polymer composition. Even more preferably, the ABS is a mixture comprising a first copolymer and a second copolymer, wherein the first copolymer comprises moieties derived from acrylonitrile, moieties derived from 1,3-butadiene and moieties derived from styrene, and the second copolymer comprises polymeric units comprising moieties derived from acrylonitrile and moieties derived from styrene, wherein the polymer composition comprises 15.0 wt % of the first copolymer and 15.0 wt % of the second copolymer, with regard to the total weight of the polymer composition.

[0041] The polymer composition according the invention may for example comprise: [0042] 50.0 and 95.0 wt % of the polycarbonate; [0043] 5.0 and 80.0 wt % of the acrylonitrile-butadiene-styrene copolymer with regard to the total weight of the polymer composition.

[0044] The polymer composition according to the present invention comprises 0.001 and 0.500 wt % of a phosphate salt of zinc, sodium, calcium, potassium or magnesium, with regard to the total weight of the polymer composition. The phosphate salt may be a monobasic phosphate salt, a dibasic phosphate salt or a tribasic phosphate salt. The phosphate salt may be a compound selected from monobasic zinc phosphate, dibasic zinc phosphate, tribasic zinc phosphate, monobasic calcium phosphate, dibasic calcium phosphate, tribasic calcium phosphate, monobasic magnesium phosphate, dibasic magnesium phosphate, tribasic magnesium phosphate, monobasic sodium phosphate, dibasic sodium phosphate, tribasic sodium phosphate, monobasic potassium phosphate, dibasic potassium phosphate, tribasic potassium phosphate, or combinations thereof.

[0045] It is preferred that the phosphate salt is a compound selected from monobasic zinc phosphate, dibasic zinc phosphate, tribasic zinc phosphate, monobasic calcium phosphate, dibasic calcium phosphate, tribasic calcium phosphate, monobasic magnesium phosphate, dibasic magnesium phosphate, tribasic magnesium phosphate, or combinations thereof.

[0046] It is particularly preferred that the phosphate salt is a compound selected from monobasic zinc phosphate, dibasic zinc phosphate, tribasic zinc phosphate, or combinations thereof.

[0047] It is even more particularly preferred that the phosphate salt is monobasic zinc phosphate.

[0048] The polymer composition according to the invention in a preferred embodiment comprises 0.001 and 0.400 wt % of the phosphate salt, more preferably 0.002 and 0.300 wt %, even more preferably 0.005 and 0.200 wt %, even more preferably 0.010 and 0.100 wt %, with regard to the total weight of the polymer composition. It is particularly preferred that the polymer composition comprises 0.001 and 0.400 wt % of the phosphate salt, more preferably 0.002 and 0.300 wt %, even more preferably 0.005 and 0.200 wt %, even more preferably 0.010 and 0.100 wt %, with regard to the total weight of the polymer composition, wherein the phosphate salt is a monobasic phosphate salt, a dibasic phosphate salt or a tribasic phosphate salt.

[0049] More particularly, it is preferred that the polymer composition comprises 0.001 and 0.400 wt % of the phosphate salt, more preferably 0.002 and 0.300 wt %, even more preferably 0.005 and 0.200 wt %, even more preferably 0.010 and 0.100 wt %, with regard to the total weight of the polymer composition, wherein the phosphate salt is a compound selected from monobasic zinc phosphate, dibasic zinc phosphate, tribasic zinc phosphate, monobasic calcium phosphate, dibasic calcium phosphate, tribasic calcium phosphate, monobasic magnesium phosphate, dibasic magnesium phosphate, tribasic magnesium phosphate, monobasic sodium phosphate, dibasic sodium phosphate, tribasic sodium phosphate, monobasic potassium phosphate, dibasic potassium phosphate, tribasic potassium phosphate, or combinations thereof. Even more particularly, it is preferred that the polymer composition comprises 0.001 and 0.400 wt % of the phosphate salt, more preferably 0.002 and 0.300 wt %, even more preferably 0.005 and 0.200 wt %, even more preferably 0.010 and 0.100 wt %, with regard to the total weight of the polymer composition, wherein the phosphate salt is a compound selected from monobasic zinc phosphate, dibasic zinc phosphate, tribasic zinc phosphate, monobasic calcium phosphate, dibasic calcium phosphate, tribasic calcium phosphate, monobasic magnesium phosphate, dibasic magnesium phosphate, tribasic magnesium phosphate, or combinations thereof. Even more particularly, it is preferred that the polymer composition comprises 0.001 and 0.400 wt % of the phosphate salt, more preferably 0.002 and 0.300 wt %, even more preferably 0.005 and 0.200 wt %, even more preferably 0.010 and 0.100 wt %, with regard to the total weight of the polymer composition, wherein the phosphate salt is a compound selected from monobasic zinc phosphate, dibasic zinc phosphate, tribasic zinc phosphate, or combinations thereof. Further particularly, it is preferred that that the polymer composition comprises 0.005 and 0.200 wt %, of the phosphate salt, more preferably 0.010 and 0.100 wt %, with regard to the total weight of the polymer composition, wherein the phosphate salt is a compound selected from monobasic zinc phosphate, dibasic zinc phosphate, tribasic zinc phosphate, or combinations thereof. Even further particularly, it is preferred that that the polymer composition comprises 0.005 and 0.200 wt %, of the phosphate salt, more preferably 0.010 and 0.100 wt %, with regard to the total weight of the polymer composition, wherein the phosphate salt is monobasic zinc phosphate.

[0050] Particularly, it is preferred that the polymer composition comprises 0.010 and 0.100 wt %, with regard to the total weight of the polymer composition of a phosphate being a monobasic phosphate salt of zinc, sodium, calcium, potassium or magnesium, preferably zinc, wherein the monobasic phosphate salt accounts for >90.0 wt %, preferably >95.0 wt % of the total of phosphate salts present in the polymer composition.

[0051] A further embodiment of the present invention relates to a polymer composition comprising: [0052] polycarbonate; [0053] acrylonitrile-butadiene-styrene copolymer; and [0054] 0.001 and 0.500 wt % of a phosphate salt of zinc, sodium, calcium, potassium or magnesium, with regard to the total weight of the polymer composition; [0055] wherein the polycarbonate has a weight average molecular weight of 35000 and 70000 g/mol as determined in accordance with the method of ISO 16014-1 (2012).

[0056] In yet a further embodiment, the present invention relates to a polymer composition comprising: [0057] 50.0 and 95.0 wt % polycarbonate; [0058] 5.0 and 80.0 wt % acrylonitrile-butadiene-styrene copolymer; and [0059] 0.001 and 0.500 wt % of a phosphate salt of zinc, sodium, calcium, potassium or magnesium, with regard to the total weight of the polymer composition; [0060] wherein the polycarbonate has a weight average molecular weight of 35000 and 70000 g/mol as determined in accordance with the method of ISO 16014-1 (2012).

[0061] In a further particularly preferred embodiment, the present invention also relates to a polymer composition comprising: [0062] 50.0 and 95.0 wt % polycarbonate; [0063] 5.0 and 80.0 wt % acrylonitrile-butadiene-styrene copolymer; and [0064] 0.001 and 0.500 wt % of a phosphate salt of zinc, sodium, calcium, potassium or magnesium, with regard to the total weight of the polymer composition; [0065] wherein the polycarbonate has a weight average molecular weight of 35000 and 70000 g/mol as determined in accordance with the method of ISO 16014-1 (2012); and wherein the phosphate salt is monobasic zinc phosphate.

[0066] Further, a particular embodiment of the invention relates to a polymer composition comprising: [0067] polycarbonate; [0068] acrylonitrile-butadiene-styrene copolymer; and [0069] 0.001 and 0.500 wt % of a phosphate salt of zinc, sodium, calcium, potassium or magnesium, with regard to the total weight of the polymer composition; [0070] wherein the polycarbonate is a mixture comprising a first polycarbonate and a second polycarbonate, the first polycarbonate has a weight average molecular weight of 30000 and <45000 g/mol and the second polycarbonate has a weight average molecular weight of 50000 g/mol and 70000 g/mol.

[0071] More particularly, the present invention also relates in one of its embodiments to a polymer composition comprising: [0072] 50.0 and 95.0 wt % polycarbonate; [0073] 5.0 and 80.0 wt % acrylonitrile-butadiene-styrene copolymer; and [0074] 0.001 and 0.500 wt % of a phosphate salt of zinc, sodium, calcium, potassium or magnesium, with regard to the total weight of the polymer composition; [0075] wherein the polycarbonate is a mixture comprising a first polycarbonate and a second polycarbonate, the first polycarbonate has a weight average molecular weight of 30000 and <45000 g/mol and the second polycarbonate has a weight average molecular weight of 50000 g/mol and 70000 g/mol.

[0076] Further more particularly, the present invention relates in yet another embodiment to a polymer composition comprising: [0077] 50.0 and 95.0 wt % polycarbonate; [0078] 5.0 and 80.0 wt % acrylonitrile-butadiene-styrene copolymer; and [0079] 0.001 and 0.500 wt % of a phosphate salt of zinc, sodium, calcium, potassium or magnesium, with regard to the total weight of the polymer composition;

[0080] wherein the polycarbonate is a mixture comprising a first polycarbonate and a second polycarbonate, the first polycarbonate has a weight average molecular weight of 30000 and <45000 g/mol and the second polycarbonate has a weight average molecular weight of 50000 g/mol and 70000 g/mol, and wherein the phosphate salt is monobasic zinc phosphate.

[0081] In another particular embodiment, the polymer composition comprises [0082] polycarbonate; [0083] 20.0 and 40.0 wt % acrylonitrile-butadiene-styrene copolymer; and [0084] 0.001 and 0.500 wt % of a phosphate salt of zinc, sodium, calcium, potassium or magnesium, with regard to the total weight of the polymer composition.

[0085] Also, an embodiment of the invention relates to a polymer composition comprising: [0086] 50.0 wt % polycarbonate; [0087] 20.0 and 45.0 wt % acrylonitrile-butadiene-styrene copolymer; and [0088] 0.001 and 0.500 wt % of a phosphate salt of zinc, sodium, calcium, potassium or magnesium, with regard to the total weight of the polymer composition.

[0089] More particularly, the invention relates to a polymer composition comprising: [0090] 50.0 wt % polycarbonate; [0091] 20.0 and 45.0 wt % acrylonitrile-butadiene-styrene copolymer; and [0092] 0.001 and 0.500 wt % of a phosphate salt of zinc, sodium, calcium, potassium or magnesium, with regard to the total weight of the polymer composition; [0093] wherein the phosphate salt is monobasic zinc phosphate.

[0094] In a particularly desired embodiment, the invention relates to a polymer composition comprising [0095] polycarbonate; [0096] 20.0 and 40.0 wt % acrylonitrile-butadiene-styrene copolymer comprising 20.0 wt % and 60.0 wt %, of moieties derived from 1,3-butadiene, with regard to the total weight of the acrylonitrile-butadiene-styrene copolymer; and [0097] 0.001 and 0.500 wt % of a phosphate salt of zinc, sodium, calcium, potassium or magnesium, with regard to the total weight of the polymer composition.

[0098] Also, an embodiment of the invention relates to a polymer composition comprising: [0099] 50.0 wt % polycarbonate; [0100] 20.0 and 45.0 wt % acrylonitrile-butadiene-styrene copolymer comprising 20.0 wt % and 60.0 wt %, of moieties derived from 1,3-butadiene, with regard to the total weight of the acrylonitrile-butadiene-styrene copolymer; and [0101] 0.001 and 0.500 wt % of a phosphate salt of zinc, sodium, calcium, potassium or magnesium, with regard to the total weight of the polymer composition.

[0102] More particularly, the invention relates to a polymer composition comprising: [0103] 50.0 wt % polycarbonate; [0104] 20.0 and 45.0 wt % acrylonitrile-butadiene-styrene copolymer comprising 20.0 wt % and 60.0 wt %, of moieties derived from 1,3-butadiene, with regard to the total weight of the acrylonitrile-butadiene-styrene copolymer; and [0105] 0.001 and 0.500 wt % of a phosphate salt of zinc, sodium, calcium, potassium or magnesium, with regard to the total weight of the polymer composition; [0106] wherein the phosphate salt is monobasic zinc phosphate.

[0107] In a further particularly desired embodiment, the invention relates to a polymer composition comprising [0108] polycarbonate; [0109] 20.0 and 40.0 wt % acrylonitrile-butadiene-styrene copolymer comprising 20.0 wt % and 60.0 wt %, of moieties derived from 1,3-butadiene, with regard to the total weight of the acrylonitrile-butadiene-styrene copolymer; and [0110] 0.001 and 0.500 wt % of a phosphate salt of zinc, sodium, calcium, potassium or magnesium, with regard to the total weight of the polymer composition; [0111] wherein the polycarbonate may has a weight average molecular weight of 35000 and 70000 g/mol as determined in accordance with the method of ISO 16014-1 (2012).

[0112] Also, an embodiment of the invention relates to a polymer composition comprising: [0113] 50.0 wt % polycarbonate; [0114] 20.0 and 45.0 wt % acrylonitrile-butadiene-styrene copolymer comprising 20.0 wt % and 60.0 wt %, of moieties derived from 1,3-butadiene, with regard to the total weight of the acrylonitrile-butadiene-styrene copolymer; and [0115] 0.001 and 0.500 wt % of a phosphate salt of zinc, sodium, calcium, potassium or magnesium, with regard to the total weight of the polymer composition; [0116] wherein the polycarbonate has a weight average molecular weight of 35000 and 70000 g/mol as determined in accordance with the method of ISO 16014-1 (2012).

[0117] More particularly, the invention relates to a polymer composition comprising: [0118] 50.0 wt % polycarbonate; [0119] 20.0 and 45.0 wt % acrylonitrile-butadiene-styrene copolymer comprising 20.0 wt % and 60.0 wt %, of moieties derived from 1,3-butadiene, with regard to the total weight of the acrylonitrile-butadiene-styrene copolymer; and [0120] 0.001 and 0.500 wt % of a phosphate salt of zinc, sodium, calcium, potassium or magnesium, with regard to the total weight of the polymer composition; [0121] wherein the phosphate salt is monobasic zinc phosphate; and wherein the polycarbonate has a weight average molecular weight of 35000 and 70000 g/mol as determined in accordance with the method of ISO 16014-1 (2012).

[0122] Further preferably, the invention relates to a polymer composition comprising: [0123] 70.0 wt % polycarbonate; [0124] 15.0 and 30.0 wt % acrylonitrile-butadiene-styrene copolymer being a mixture comprising a first copolymer and a second copolymer, wherein the first copolymer comprises moieties derived from acrylonitrile, moieties derived from 1,3-butadiene and moieties derived from styrene, and the second copolymer consists of polymeric units comprising moieties derived from acrylonitrile and moieties derived from styrene; and [0125] 0.010 and 0.100 wt % of a phosphate salt being a monobasic phosphate salt of zinc, sodium, calcium, potassium or magnesium with regard to the total weight of the polymer composition.

[0126] In a particularly preferred embodiment, the invention relates to a polymer composition comprising: [0127] 70.0 wt % polycarbonate; [0128] 15.0 and 30.0 wt % acrylonitrile-butadiene-styrene copolymer being a mixture comprising a first copolymer and a second copolymer, wherein the first copolymer comprises moieties derived from acrylonitrile, moieties derived from 1,3-butadiene and moieties derived from styrene, and the second copolymer consists of polymeric units comprising moieties derived from acrylonitrile and moieties derived from styrene; and [0129] 0.010 and 0.100 wt % of a phosphate salt being a monobasic phosphate salt of zinc, sodium, calcium, potassium or magnesium with regard to the total weight of the polymer composition wherein the monobasic phosphate salt accounts for >90.0 wt % of the total of phosphate salts present in the polymer composition.

[0130] Even further particularly preferred is an embodiment wherein the invention relates to a polymer composition comprising: [0131] 70.0 wt % polycarbonate; [0132] 15.0 and 30.0 wt % acrylonitrile-butadiene-styrene copolymer being a mixture comprising a first copolymer and a second copolymer, wherein the first copolymer comprises moieties derived from acrylonitrile, moieties derived from 1,3-butadiene and moieties derived from styrene, and the second copolymer consists of polymeric units comprising moieties derived from acrylonitrile and moieties derived from styrene, wherein the polymer composition comprises 15.0 wt % of the first copolymer and 15.0 wt % of the second copolymer, with regard to the total weight of the polymer composition; and [0133] 0.010 and 0.100 wt % of a phosphate salt being a monobasic phosphate salt of zinc, sodium, calcium, potassium or magnesium with regard to the total weight of the polymer composition wherein the monobasic phosphate salt accounts for >90.0 wt % of the total of phosphate salts present in the polymer composition.

[0134] Also particularly preferred is an embodiment wherein the invention relates to a polymer composition comprising: [0135] 70.0 wt % polycarbonate; [0136] 15.0 and 30.0 wt % acrylonitrile-butadiene-styrene copolymer being a mixture comprising a first copolymer and a second copolymer, wherein the first copolymer comprises moieties derived from acrylonitrile, moieties derived from 1,3-butadiene and moieties derived from styrene, and the second copolymer consists of polymeric units comprising moieties derived from acrylonitrile and moieties derived from styrene, wherein the polymer composition comprises 15.0 wt % of the first copolymer and 15.0 wt % of the second copolymer, with regard to the total weight of the polymer composition; and [0137] 0.010 and 0.100 wt % of a phosphate salt being a monobasic phosphate salt of zinc, sodium, calcium, potassium or magnesium wherein the monobasic phosphate salt is the only phosphate salt present in the polymer composition.

[0138] The invention also relates to an injection moulded article produced using the polymer composition according to the present invention.

[0139] The invention will now be illustrated by the following non-limiting examples.

[0140] For the experiments that were performed to demonstrate the present invention, the materials as listed in table I below were used.

TABLE-US-00001 TABLE I Materials PC1 Lexan ML5221-111N, a bisphenol-A based polycarbonate produced via interfacial polymerisation, having M.sub.w of about 41000 g/mol, obtainable from SABIC PC2 Lexan 102L-11204, a bisphenol-A based polycarbonate produced via melt polymerisation, having M.sub.w of about 55000 g/mol, obtainable from SABIC ABS ABS HR181, an acrylonitrile-butadiene-styrene copolymer produced via emulsion polymerisation, comprising 50.0 wt % of units derived from butadiene, obtainable from Kumho SAN SAN INP581, an acrylonitrile-styrene copolymer produced via mass polymerisation, obtainable from SABIC PETS Pentaerythritol tetrastearate, CAS reg. no. 115-83-3, obtainable from FACI AO Irganox 1076, CAS reg. no. 2082-79-3, obtainable from BASF PH Irgafos 168, Tris(2,4-di-tert-butylphenyl)phosphite, CAS reg. no. 31570-04-4, obtainable from BASF MZP Z 21-82, Monobasic zinc phosphate, CAS reg. no. 13598-37-3, obtainable from Budenheim PA Phosphorous acid 45%, CAS reg. no. 10294-56-1, obtainable from Sinopharm CB M800, a carbon black, CAS reg. no. 1333-86-4, obtainable from Cabot

[0141] Using the above listed materials, a number of polymer compositions were prepared via melt compounding according to the formulations as presented in table II below. The melt compounding was performed in a Toshiba twin screw extruder having a screw length of 1517 mm, at a barrel temperature of 260 C., a screw speed of 400 rpm and a throughput of 60 kg/h. Formulations 1 and 2 present polymer compositions according to the present invention. Formulations 3-6 present comparative examples.

TABLE-US-00002 TABLE II Formulations of polymer compositions 1 2 3 4 5 6 PC1 36.24 36.24 36.24 36.24 36.24 36.24 PC2 37.00 37.00 37.00 37.00 37.00 37.00 ABS 11.40 11.40 11.40 11.40 11.40 11.40 SAN 14.40 14.40 14.40 14.40 14.40 14.40 PETS 0.30 0.30 0.30 0.30 0.30 0.30 AO 0.08 0.08 0.08 0.08 0.08 0.08 PH 0.08 0.08 0.08 0.08 0.08 0.10 MZP 0.005 0.05 PA 0.05 0.10 CB 0.50 0.50 0.50 0.50 0.50 0.50 The quantities as presented in table II represent parts by weight.

[0142] Of each of the polymer compositions that were prepared, various properties including materials properties, processing properties and surface appearance properties were determined as presented in table III.

TABLE-US-00003 TABLE III Properties of experimental polymer compositions. 1 2 3 4 5 6 MFR 20.1 21.2 21.0 21.8 21.3 22.6 Izod 23 699 702 696 682 705 703 Izod 30 550 550 544 546 566 571 TM 2300 2313 2329 2262 2305 2295 HDT 114 115 116 115 113 114 PC M.sub.w 11.7 6.5 10.0 11.8 16.0 13.0 SSR 25 50 100 120 0 10

[0143] Wherein: [0144] MFR is the melt mass flow rate as determined in accordance with ASTM D1238 (2013), at a temperature of 260 C. and a loading of 5.00 kg, expressed in g/10 min. The MFR may be considered an indicator for the processability of the polymer composition. A higher melt mass flow rate indicates a less viscous and thus better flowing polymer composition. [0145] Izod 23 is the notched Izod impact strength as determined in accordance with ASTM D256 (2010) at 23 C., expressed in J/m. [0146] Izod 30 is the notched Izod impact strength as determined in accordance with ASTM D256 (2010) at 30 C., expressed in J/m. [0147] TM is the tensile modulus as determined in accordance with ASTM D638 (2014), expressed in MPA. [0148] HDT is the heat deflection temperature as determined in accordance with ASTM D648 (2016) using samples of 6.4 mm under a load of 1.82 MPa, expressed in C. [0149] PC M.sub.w is the reduction of the molecular weight M.sub.w of the polycarbonate in the polymer composition after subjecting the polymer composition to abusive moulding conditions by exposure for a period of 20 min to a temperature of 300 C. in a moulding machine. The M.sub.w of the polycarbonate was determined on the polymer composition as prepared by melt compounding (M.sub.w1) and on the polymer composition obtained after subjecting the polymer composition to the abusive conditions (M.sub.w2). The M.sub.w was determined via size-exclusion chromatography using polycarbonate standards, via the method of ISO 16014-1 (2012). M.sub.w is expressed in % and was calculated as:

[00001]$.Math..Math.M_w=\frac{M_w.Math.1-M_w.Math.2}{M_w.Math.1}*100.Math.\%$ [0150] SSR is the reduction of silver streaks on the surface of moulded plaques compared to a standard, expressed in %. For determination of the silver streak reduction, composition 5 was taken as standard; it represent the polymer composition without any measures taken to improve the surface properties in term of silver streaks. For determination of the quantity of silver streaks, a quantity of material of each of the polymer compositions was subjected to a dwell time in an injection moulding machine of 20 min at 300 C., upon which plaques were moulded having a length of 90 mm, a width of 60 mm and a thickness of 2.0 mm. By visual inspection, the quantity of silver streaks on each plaque was determined. The reduction of silver streaks SSR for each of the polymer compositions was determined via:

[00002]${\mathrm{SSR}}_n=\frac{{\mathrm{SS}}_n-{\mathrm{SS}}_5}{{\mathrm{SS}}_5}*100.Math.\%$ [0151] Wherein [0152] SSR.sub.n=the silver streak reduction for a given polymer composition n; [0153] SS.sub.n=the number of silver streaks observed on sample plaques of polymer composition n; and [0154] SS.sub.5=the number of silver streaks observed on sample plaques of polymer composition 5. [0155] A positive SSR indicates a reduction of silver streaks; a negative SSR indicates an increase of silver streaks.

[0156] The above examples show that the polymer composition according to the present invention demonstrates desirable materials properties, as indicated by the Izod impact strength and the tensile modulus, desirable thermal properties as indicated by the heat deflection temperature, desirable processing properties as indicated by the melt mass flow rate, and provide an unexpected reduction of the quantities of sliver streaks. It is further demonstrated by polymer composition 2 that incorporation of a quantity of 0.02 and 0.10 wt % of zinc phosphate provides a particular reduction of the quantity of silver streaks combined with a particular low reduction of the molecular weight of the polycarbonate after abusive moulding.