WO2011050521A1

WO2011050521A1 - Polymer composition with improved properties and preparation method thereof

Info

Publication number: WO2011050521A1
Application number: PCT/CN2009/074654
Authority: WO
Inventors: Werner Hoess; Yujun Zhang; Victor Khrenov; Cheng Xu; Guomin Liu; Feng Zhao; Siewfong Low
Original assignee: Evonik Roehm GmbH
Current assignee: Roehm GmbH Darmstadt
Priority date: 2009-10-28
Filing date: 2009-10-28
Publication date: 2011-05-05
Anticipated expiration: 2012-04-28
Also published as: TW201130907A

Abstract

The present invention relates to a polymer composition with improved optical and surface properties and a preparation method thereof. The polymer composition comprises a) 1-90 wt% of a polyblend A comprising polybutadiene and a methyl methacrylate based polymer, b) 1-90 wt% of a polymer B, which is a methyl methacrylate based polymer, and c) 1-20 wt% of a copolymer C comprising 18-35 wt% maleic anhydride and 65-82 wt% styrene.

Description

Polymer composition with improved properties and

preparation method thereof

Description

Technical Field

The present invention relates to acrylic based blend polymers with improved optical and surface properties.

Background Art

It is well known that Poly(methyl methacrylate) (PMMA) has advantages in surface hardness, glossiness and weatherability. By adding polybutadiene modifier to PMMA, impact resistance can be increased. Blends of PMMA and polybutadiene modifiers have been prepared and show advantages in their comprehensive properties. However, these products show some haze caused by incompability of the components (such as Acrylite XT® polymer or CYROLITE® from EVONIK). For electronic housing applications, there is a trend to use transparent colors.

Impact resistant polymer products as a combination of PMMA, SAN (the copolymer of styrene and acrylonitrile) and MBS (methyl methacrylate-butadiene-styrene copolymer) are known. One example is Terlux® from BASF.

German patent DE2024940 discloses a composition containing :

1) 10-90 parts by weight of a copolymer of

70-90 wt% styrene

10-30 wt% maleic anhydride

2) 10-90 parts by weight of a copolymer of

60-100 wt% methyl methacrylate

30-0 wt% styrene

10-0 wt% of a C1-C4 alkyl acrylate

3) 0-50 parts by weight of a copolymer of

60-90 wt% styrene

40-10 wt% acrylonitrile.

Furthermore, W098/28365 discloses a polymer composition consisting of:

a. 5-95 wt% of a copolymer of

90-99.8 wt% methyl methacrylate

10-0.2 wt% ethyl acrylate and/or methyl acrylate

b. 95-5 wt% of a copolymer of

72-80 wt% styrene

20-28 wt% maleic anhydride, which also possesses a good transparency and a low haze. US2002/0167112 discloses an acrylic based multipolymer molding and extrusion composition possessing improved optical properties and low temperature impact resistance, comprising:

A) 55-85 wt% of an acrylic based multipolymer comprising in wt%:

8-12% acrylonitrile, 3-8% butyl acrylate, 3-5% ethyl acrylate, 3-8% methyl acrylate, 65-80% methyl methacrylate, and 15-30% styrene,

B) 15-45 wt% of a methyl methacrylate-butadiene-styrene (MBS) copolymer modifier polymerized by a free radical process.

The products with acrylonitrile are toxic and those in W098/28365 lack suitable surface hardness.

Nontoxic transparent products combining inherent high gloss surface with high scratch resistance and high impact resistance are always required, especially for food packaging and toy industries.

Contents of Invention

The aim of the present invention is to provide a polymer composition with high transparency, high surface hardness, high gloss and good impact resistance and free of acrylonitrile.

This aim is achieved by providing a polymer composition comprising the following components: based on the total weight of the polymer composition,

a) 1-90 wt% of a polyblend A comprising polybutadiene and a methyl methacrylate based polymer,

b) 1-90 wt% of a polymer B which is a methyl methacrylate based polymer, and c) 1-20 wt% of a copolymer C comprising 18-35 wt% maleic anhydride and 65-82 wt% styrene,

wherein the methyl methacrylate based polymer in polyblend A and the methyl methacrylate based polymer as polymer B can be identical or different and independently each other is a polymer comprising 50-100 wt%, preferably 65-100wt% methyl methacrylate and 0-50 wt%, preferably 0-35wt% coacrylates, in polymerization form, based on the weight of the methyl methacrylate based polymer.

The invention also provides a process to prepare the present invention polymer composition, where polymers with different ratio of the components are melted and compounded, preferably with single or twin screw extruders, at 150-300 °C, preferably at 190-250 °C.

Specific Mode for Carrying Out the Invention

The desired polymer composition in present invention has a haze of at most 10%, preferably at most 8% and most preferably at most 5% determined according to ASTM D1003, a pencil hardness of HB, preferably 1 H and most preferably 2H determined according to ASTM D3363, and an impact resistance of >20KJ/m², preferably >40KJ/m² and most preferably >60KJ/m² at 23°C according to ISO 179.

The preferred polymer composition comprises the following components: based on the total weight of the polymer composition,

a) 10-85 wt% of a polyblend A comprising polybutadiene and a methyl methacrylate based polymer,

b) 10-85 wt% of a polymer B, which is a methyl methacrylate based polymer, and c) 5-15 wt% of a copolymer C comprising 18-35 wt% maleic anhydride and 65-82 wt% styrene.

In the present invention, the 'methyl methacrylate based polymer' in polyblend A could be the same as or different from polymer B, which independently each other is a polymer comprising 50-100 wt%, preferably 65-100 wt% methyl methacrylate and 0-50 wt%, preferably 0-35 wt% coacrylates, in polymerization form, based on the weight of the methyl methacrylate based polymer.

The coacrylates which could be used in methyl methacrylate based polymer are widely known. They include, among others, (meth)acrylates which derive from saturated alcohols, such as methyl acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, tert-butyl (meth)acrylate, pentyl (meth)acrylate and 2-ethylhexyl (meth)acrylate, for example; (meth)acrylates which derive from unsaturated alcohols, such as oleyl (meth)acrylate, 2-propynyl (meth)acrylate, allyl (meth)acrylate, vinyl (meth)acrylate, for example; aryl (meth)acrylates, such as benzyl (meth)acrylate or phenyl (meth)acrylate, it being possible for the aryl radicals in each case to be unsubstituted or to be substituted up to four times; cycloalkyl (meth)acrylates, such as 3-vinylcyclohexyl (meth)acrylate, bornyl (meth)acrylate; hydroxylalkyl (meth)acrylates, such as 3-hydroxypropyl (meth)acrylate, 3,4-dihydroxy-butyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate; glycol di(meth)acrylates, such as 1 ,4-butanediol (meth)acrylate, (meth)acrylates of ether alcohols, such as tetra-hydrofurfuryl (meth)acrylate, vinyloxyethoxyethyl (meth)acrylate; amides and nitriles of (meth)acrylic acid, such as N-(3-dimethylaminopropyl) (meth)acryl-amide, N-(diethylphosphono)(meth)acrylamide, 1-meth- acryloylamido-2-methyl-2-propanol; sulphur-containing methacrylates, such as ethylsulphinylethyl (meth)acrylate, 4-thiocyanatobutyl (meth)acrylate, ethyl-sulphonylethyl (meth)acrylate, thiocyanatomethyl (meth)acrylate, methylsulphinylmethyl (meth)acrylate, bis((meth)acryloyloxyethyl) sulphide; polyfunctional (meth)acrylates, such as trimethylolpropane tri(meth)acrylate.

Among these, methyl acrylate and ethyl (meth) acrylate are preferred.

Besides the coacrylates set out above, further unsaturated comonomers uased as coacrylates contained in the methyl methacrylate based polymer are those copolymerizable with methyl methacrylate and with the aforementioned (meth)acrylates. Such monomers include, among others, 1-alkenes, such as hex-1-ene, hept-1-ene; branched alkenes, such as vinylcyclohexane, 3,3-dimethyl-1-propene, 3-methyl-1-diisobutylene, 4-methylpent-1-ene, for example; vinyl esters, such as vinyl acetate; styrene, substituted styrenes having an alkyl substituent in the side chain, such as [alpha]-methylstyrene and [alpha]-ethylstyrene, for example, substituted styrenes with an alkyl substituent on the ring, such as vinyltoluene and p-methylstyrene, halogenated styrenes, such as monochlorostyrenes, dichlorostyrenes, tribromostyrenes and tetrabromo-styrenes, for example; heterocyclic vinyl compounds, such as 2-vinylpyridine, 3-vinylpyridine, 2-methyl-5-vinylpyridine, 3-ethyl-4-vinylpyridine, 2,3-dimethyl-5-vinylpyridine, vinylpyrimidine, vinylpiperidine, 9-vinylcarbazole, 3-vinylcarbazole, 4-vinylcarbazole, 1-vinylimidazole, 2-methyl-1-vinylimidazole, N-vinyl-pyrrolidone, 2-vinylpyrrolidone, N-vinylpyrrolidine, 3-vinylpyrrolidine, N-vinylcaprolactam, N-vinylbutyro-lactam, vinyloxolane, vinylfuran, vinylthiophene, vinylthiolane, vinylthiazoles and hydrogenated vinyl-thiazoles, vinyloxazoles and hydrogenated vinyl-oxazoles; vinyl and isoprenyl ethers; and dienes, such as divinylbenzene, for example.

In general these comonomers are used in an amount of 0 wt% to 50 wt%, preferably 0 wt% to 30 wt% based on the weight of the methyl methacrylate based polymer, it being possible for the compounds to be used individually or as a mixture.

Said polyblend A comprises polybutadiene in an amount of 1-20 wt%, preferably 10-20 wt%, and a methyl methacrylate based polymer in an amount of 80-99 wt%, preferably 80-90 wt%, based on the weight of polyblend A. Said methyl methacrylate based polymer comprises 50-100 wt%, preferably 65-100 wt% methyl methacrylate and 0-50 wt%, preferably 0-35 wt% coacrylates, in polymerization form, based on the weight of the methyl methacrylate based polymer.

Particularly, in the present invention, the methyl methacrylate based polymer comprises 65-95wt% MMA, 5-25wt% styrene, 0-10wt% ethyl acrylate, based on the weight of the methyl methacrylate based polymer.

Said polyblend A, or the blend of polybutadiene and a methyl methacrylate based polymer (B-PMMA for short), could be selected from Acrylite XT® polymer, CYROVU ® or CYROLITE ® from EVONIK, KANE ACE ® from Kaneka, and BTE 731 ® from Rohm&Haas.

Preferably, said polymer B is used in amount of 10-40 wt%, more preferably 20-30 wt% based on the total weight of the polymer composition. The polymer B preferably has a weight-average molecular weight of from 40,000g/mol to 400 OOOg/mol; more preferably 80,000g/mol to 200, OOOg/mol and most preferably 120, OOOg/mol to 160, OOOg/mol. Said polymer B could be selected from standard PLEXGLAS® molding compounds series from EVONIK, e.g. PLEXGLAS ® 6N, PLEXGLAS ® 8N and others.

Preferably, said copolymer C is used in amount of 3-9 wt%, more preferably 5-7 wt%, based on the total weight of the polymer composition. The copolymer C preferably has a weight-average molecular weight of from 10,000 to 500,000 g/mol; more preferable of from 79,000 to 175,000 g/mol. Said copolymer C, the copolymer of styrene and maleic anhydride (SMA for short), could be selected from XIRAN® from Polyscope Polymers B.V. 6161 RA Geleen, Netherland.

The polymer composition can also comprise, alongside of polyblend A, polymer B, and copolymer C, in a manner known per se, conventional additives, and/or auxiliaries, examples being heat stabilizers, UV stabilizers, UV absorbers, antioxidants, and/or colorants, pigments, or organic dyes. It is preferable that the amount of conventional additives, and/or auxiliaries present is not more than 10% by weight, particularly preferably not more than 5% by weight, in particular not more than 2% by weight, based on the total weight of the polymer composition. The polymer composition can, if appropriate, also comprise absolutely no additives, and/or auxiliaries.

Good results are furthermore obtained if the additives have a high acidity. This ensures that the formation of gas bubbles in the polymer composition, probably caused by the decomposition of SMA, is prohibited.

Boric acid for example is very suitable for use as a thermal stabilizer.

Good results are furthermore obtained with UV stabilizers that also have a high acidity, preferably with a pKa of at most 8, more preferably at most 7, even more preferably at most 6, the pKa having been determined in a mixture of 50 wt% isopropyl alcohol and 50 wt% water at 23°C. Examples of this are 2-(2'-hydroxy-5'-methyl-phenyl)-benzotriazole or hindered amine light stabilizers (HALS) compounds, such as 8-acetyl-3-dodecyl-7,7,9,9-tetra-methyl- 1 ,3,8-triazaspiro(4,5)decane-2,4-dione for example.

Preferably UV stabilizers are used in an amount of 0.005-2.0 wt%, based on the total weight of the polymer composition.

If use is made of a UV stabilizer with a high acidity, for example one of those mentioned above, it is possible to use a second UV stabilizer with a lower acidity, provided that the second UV stabilizer is present in a lower concentration than the first one.

It is for example possible to use 0.4-1.5 wt% 8-acetyl-3-dodecyl-7,7,9,9- tetra-methyl-1 ,3,8-triazospiro(4,5)decane-2,4-dione in combination with 0.1-0.5 wt% di-(2,2,6,6-tetra-methyl-4-piperidyl)-sebacate.

Benzotriazole derivatives are also suitable UV absorbers, which is selected from the group consisting of 2-(2'-hydroxy-5'-methylphenyl)-benzotriazole, triazine derivatives, e.g. 2-(4,6-diphenyl-1 ,3,5-triazin-2-yl)-5-hexyloxy)phenol, hindered amine light stabilizers, and combinations thereof. These benzotriazole derivatives could be obtained in the name of TINUVIN® from Ciba.

For the polybutadiene modified polymers in the present invention, antioxidants as octadecyl-3-(3,5-di-tert.butyl-4-hydroxyphenyl)-propionate in the name of IRGANOX® 1076 from Ciba is more preferred.

For the injection-molding process, lubricants or mold-release agents are particularly important, and can reduce the level of, or entirely prevent, possible adhesion of the polymer composition to the injection mold. Furthermore, many moldings, particularly injection-molded parts, are non-transparent but have a color, therefore comprising colorants, pigments, or organic dyes, as additives. Parts for outdoor uses generally comprise UV stabilizers, UV absorbers, or antioxidants for additional protection from weathering.

Lubricants can therefore be used as auxiliaries, examples being those selected from the group of the saturated fatty acids whose number of carbon atoms is less than 20, preferably from 16 to 18, or from the saturated fatty alcohols whose number of carbon atoms is less than 20, preferably from 16 to 18. Quantitative proportions present are preferably very small, at most 0.25% by weight, for example from 0.05 to 0.2% by weight, based on the polymer composition.

Examples of suitable lubricants are stearic acid, palmitic acid, industrial mixtures composed of stearic and palmitic acid. Examples of other suitable lubricants are n-hexadecanol, n-octadecanol, and industrial mixtures composed of n-hexadecanol and n-octadecanol. Stearyl alcohol is a particularly preferred lubricant or mold-release agent.

In producing the present polymer composition, one preferably begins with solids in the form of, e.g., polymer beads or granulates, with the use of a slowly moving mixing apparatus, e.g., a drum mixer, a free-fall-mixer, a spiral mixing wheel, or a double-chamber plow-type mixer. The slowly moving mixer produces mechanical mixing without eliminating phase boundaries (see 'Ullmans Encyklopaedie der technischen Chemie', 4th Ed., Verlag Chemie.Vol. 2, pp.282-311). This is followed by thermoplastic processing by homogeneous mixing in the melt, with the using of heatable mixing apparatus at suitable temperatures, in kneader mixers or preferable in extruders, e.g. single or twin screw or multiple screw extruders or extruders with oscillating screws and shear rods, like Cokneader Buss® from Buss Corporation. Afterwards the dried granulates are injection molded into plates or other specimen, needed for the described tests.

Examples

The compounding components and their codes are summarized here.

Component Material

Polyblend A B-PMMA-1

B-PMMA-2

Polymer B PMMA-1 PMMA-2

Copolymer C SMA-1

SMA-2

B-PMMA-1 is a polyblend of 15-16 wt% polybutadiene and 84-85 wt% methyl methacrylate based polymer based on the weight of the polyblend, wherein the methyl methacrylate based polymer comprises 65-70wt% MMA, 20-25wt% styrene, 5-10wt% ethyl acrylate, based on the weight of methyl methacrylate based polymer. B-PMMA-1 is provided from EVONIK.

B-PMMA-2 is a polyblend of 20 wt% polybutadiene and 80wt% methyl methacrylate based polymer based on the weight of the polyblend, wherein the methyl methacrylate based polymer comprises about 94wt% MMA, 6 wt% styrene, based on the weight of methyl methacrylate based polymer. B-PMMA-2 is provided from Kaneka.

PMMA-1 is a polymer of 90-92wt% MMA and 8-10%wt% methyl acrylate. PMMA-1 is provided from EVONIK.

PMMA-2 is a polymer of 98-99 wt% MMA, and 1-2 wt% methyl acrylate. PMMA-2 is provided from EVONIK.

SMA-1 is a copolymer of 26wt% maleic anhydride and 74wt% styrene with a viscosity number of 0.335dl/g according to ISO 1628. SMA-1 is provided by Polyscope.

SMA-2 is a copolymer of 23wt% maleic anhydride and 77% wt% styrene with a molecular weight Mw of 110,000 g/mol. SMA-2 is provided by Polyscope.

In the present invention, the weight-average molecular weight of polymer is determined according to GPC process in a manner known in the art.

Example a)

A mixture with 70wt% B-PMMA-1 , 24wt% PMMA-1 and 6wt% SMA-1 was mixed by a vertical batch mixer (Type SVM-25; from Shini Machinery) for 3 min.

The mixture was compounded by single screw extruder with 30 mm screw diameter (Type SSE30; from Ruiya) with melt temperature 240°C and rotation speed 50 rpm. Strands out of the die went through a water tank, cooled down and were pelletized.

The granules were dried with desiccant-drier MOTAN at 80°C for 2 h and then injection molded on melt temperature of 240°C in a injection molding machine SUMITOMO SED50 into specimens of 80x10x4 mm for impact testing and plates of 3 mm thickness for testing optical properties and pencil hardness.

The pencil hardness is tested according to ASTM D3363.

The plate has a transmission of the plate of 90 %( according to ASTM D1003), a haze of 5 % and the Charpy impact strength of 87.0 kJ/m²(according to ISO 179). The plate looks crystal clear. The haze value of products is measured according to ASTM D1003 by Spectrometer GRETAG MCBETH COLOREYE 7000. According to ASTM D1003, material having a haze value greater than 30 % is considered diffusing.

The products are free of toxic substances and substances which are suspected of causing cancer, like acrylonitrile.

The product combines low haze and high impact level with outstanding surface hardness of pencil hardness of 1 H.

Comparative Example 1

A mixture with 70 wt% B-PMMA-1 and 30 wt% PMMA-1 was mixed with a vertical batch mixer (Type SVM-25 from Shini Machinery) for 3 min.

Afterwards the mixture was compounded and injection molded as described in Example a).

The plate prepared by the comparative example is very hazy and looks translucent. Examples b1-3)

Mixtures with 15/40/68 wt% PMMA-1 , 80/50/15 wt% B-PMMA-1 and 5/10/17 wt% SMA-1 respectively were mixed with a vertical batch mixer (Type SVM-25 from Shini Machinery) for 3 min.

Afterwards the mixtures were compounded and injection molded as described in Example a).

Test results of Example a), Comparative Example 1 and Examples b1-3) are listed in table 1 below.

Tab 1 Test results of Examples a), b1-3) and Comparative Example 1

Example Comparative Example Example Example

Components Unit

a) Example 1 b1 ) b2) b3)

B-PMMA-1 wt% 70 70 80 50 15

PMMA-1 wt% 24 30 15 40 68

SMA-1 wt% 6 0 5 10 17

Properties

Transmission

% 90 82 90.2 90 91 (3 mm, A2)

Haze (3 mm) % 5 46 4 4 4

Pencil

1 H 1 H 2H 2H 3H hardness Charpy

impact kJ/m² 87.0 89.0 68 60 40 strength

Comparative Example 2

A mixture with 67 wt% PMMA-1 and 33 wt% B-PMMA-2 was mixed with a vertical batch mixer (Type SVM-25 from Shini Machinery) for 3 min.

Example c)

A mixture with 50 wt% PMMA-1 , 33 wt% B-PMMA-2 and 17 wt% SMA-2 was mixed with a vertical batch mixer (Type SVM-25 from Shini Machinery) for 3 min.

Example d)

A mixture with 74.5 wt% PMMA-2, 17 wt% B-PMMA-2 and 8.5 wt% SMA-2 was mixed with a vertical batch mixer (Type SVM-25 from Shini Machinery) for 3 min.

Tab 2 Test results of Examples c), d) and Comparative Example 2

Comparative

Components Unit Example c) Example d)

example 2

B-PMMA-2 wt% 33 33 17

PMMA-1 wt% 67 50 0

PMMA-2 wt% 0 0 74.5

SMA-2 wt% 0 17 8.5

Properties

Transmission (3 mm, A2) % 44.5 89.6 90 Haze, 23°C % 47 4.3 5

Charpy impact strength kJ/m² 79.0 75.0 65

Pencil hardness B 1 H 2H

Table 3 shows the best optical property (highest transmission and lowest haze) is achieved around 6 wt% SMA-1 when the compositions contains 70wt% B-PMMA-1 , wherein in Examples e) and f), the mixture was compounded and injection molded as described in Example a).

Tab.3 Formulations of compositions containing 70wt% B-PMMA-1 and different amounts of SMA-1

The following Table 4 shows the formulations and test results for compositions containing 80% B-PMMA-1. Here the haze value of the blends also shows a minimum around 5 wt% SMA-1 , wherein in Examples g) and h), the mixture was compounded and injection molded as described in Example a).

Tab.4: Formulations of compositions containing 80 wt% B-PMMA-1

Materials Unit Example b) Example g) Example h)

B-PMMA-1 wt/% 80 80 80

PMMA-1 wt/% 15 16 14

SMA-1 wt/% 5 4 6 Properties

Transmission

% 90.2 89 89.4

(3mm,A2)

Haze(3mm) % 4 5.0 5.6

The influence of temperature on haze value of polyblends was also tested.

Polyblends based on SMA-1 were conditioned in an oven under different temperatures for 2 h and then taken out for haze measurement immediately. Table 5 shows the test results.

Haze of compound with 6 wt% of SMA-1 keeps almost the same when temperature is increased from 4°C to 50°C.

Table 5: Haze values of polyblends with or without SMA-1 after 2 h annealing at 4°C,

23°C, 35°C and 50°C

The table 5 shows that the haze values of polyblends with 6 % of SMA-1 still remain low in the annealing process.

Claims

1. A polymer composition containing the following components: based on the total weight of the polymer composition,

b) 1-90 wt% of a polymer B, which is a methyl methacrylate based polymer, and c) 1-20 wt% of a copolymer C comprising 18-35 wt% maleic anhydride and 65-82 wt% styrene,

wherein the methyl methacrylate based polymer in polyblend A and the methyl methacrylate based polymer as polymer B can be identical or different and independently each other is a polymer comprising 50-100 wt%, preferably 65-100wt% methyl methacrylate and 0-50 wt%, preferably 0-35wt% coacrylates in polymerization form, based on the weight of the methyl methacrylate based polymer.

2. The polymer composition according to claim 1 , containing the following components: based on the total weight of the polymer composition,

b) 10-85 wt% of a polymer B which is a methyl methacrylate based polymer, and c) 5-15 wt% of a copolymer C comprising 18-35 wt% maleic anhydride and 65-82 wt% styrene.

3. The polymer composition in claim 1 or 2, wherein the polymer composition has a haze of at most 10 %, preferably at most 8 % and most preferably at most 5 %, a pencil hardness of HB, preferably 1 H and most preferably 2H, and an impact resistance of >20 KJ/m², preferably >40 KJ/m² and most preferably >60 KJ/m² at 23°C according to ISO 179.

4. The polymer composition in claim 1 or 2, wherein the polymer composition has a haze of at most 5 %, a pencil hardness of 1 H and an impact resistance of >40 KJ/m² at 23 °C according to ISO 179.

5. The polymer composition in claim 1 or 2, wherein in the whole polyblend A the polybutadiene is in an amount of 1-20 wt%, preferably 10-20 wt%, and the methyl methacrylate based polymer is in an amount of 80-99 wt%, preferably 80-90 wt%, based on the weight of polyblend A.

6. The polymer composition in claim 1 or 2, wherein in the polymer composition the copolymer C is in an amount of 3-9 wt%, preferably 5-7 wt% based on the total weight of the polymer composition.

7. The polymer composition in claim 1 or 2, wherein the copolymer C has a weight-average molecular weight of from 10,000 to 500,000 g/mol; preferable of from 79,000 to 175,000 g/mol.

8. The polymer composition in claim 1 or 2, wherein in the whole composition the polymer B is in an amount of 10-40 wt%, preferably 20-30 wt% based on the total weight of the polymer composition.

9. The polymer composition in claim 1 or 2, wherein the polymer B has a weight-average molecular weight of from 40, OOOg/mol to 400 OOOg/mol; preferably 80, OOOg/mol to 200, OOOg/mol and more preferably 120, OOOg/mol to 160,000g/mol.

10. A process to prepare the polymer composition according to any one of claims 1 to 9, where polymers with different ratio of the components are melt and compounded, preferably with single or twin screw extruders, at 150-300°C, preferably at 190-250°C.