Propylene-butylene copolymers with improved mechanical and optical properties and better processability as well as articles made therefrom
The present invention relates to nucleated propylene-butylene copolymers comprising propylene and butylene monomer units, wherein the nucleated propylene-butylene copolymer has improved stiffness, better impact behaviour and optical properties such as low haze and improved optomechanical ability.
1. A nucleated propylene-butylene-copolymer which
i) has been produced in the presence of a Ziegler-Natta catalyst and is
ii) free of phthalic acid esters, and comprises, based on the total weight of the propylene-butylene copolymer,
A. 88.0-96.0 wt.-% of propylene; and
B. 4.0-12.0 wt.-% of 1-butylene,
wherein the nucleated propylene-butylene copolymer is further characterised by:
a) a molecular weight distribution (MWD) of at least 5.0 when measured according to ISO16014,
b) and fulfils any of the following requirements:
c1) Flexural Modulus of at least 1000 MPa when measured according to ISO178 or
c2) Notched Impact strength of at least 3.0 kJ/m 2 when measured according to ISO 179/1eA+23° C. or
c4) ratio of Flex Modulus/Haze of at least 60 MPa/% or
c5) an optomechanical ability or a process focused optomechanical ability of at least 200.
2. A nucleated propylene-butylene copolymer according to claim 1 further characterized by a MFR 230/2.16 of at least 10.0 g/10 min when measured according to ISO113.
3. A nucleated propylene-butylene copolymer according to claim 1 further characterized by a Notched Impact strength of at least 3.0 kJ/m 2 when measured according to ISO 179/1eA+23° C.
4. A nucleated propylene-butylene copolymer according to claim 1 further characterized by a Haze of at most 21.0% when measured according to ASTM 1003-D on 1 mm plaques.
5. A nucleated propylene-butylene copolymer according to claim 1 further characterized by a ratio of Flex Modulus/Haze of at least 60 MPa/%.
6. A nucleated propylene-butylene copolymer according to claim 1 further characterized by a optomechanical ability or a process focused optomechanical ability of at least 200.
7. A nucleated propylene-butylene copolymer according to claim 1 , fulfilling any two of the following requirements:
Flexural Modulus at least 1000 MPa when measured according to ISO178; or
Notched Impact strength at least 3.0 kJ/m 2 when measured according to ISO 179/1eA+23° C.; or
Haze of at most 21.0% when measured according to ASTM 1003-D on 1 mm plaques; or
ratio of Flex Modulus/Haze of at least 60 MPa/%; or
an optomechanical ability of at least 200.
8. A nucleated propylene-butylene copolymer according to claim 1 which has been produced in the presence of a Ziegler-Natta catalyst and an internal donor selected from (di)esters of non-phthalic carboxylic (di)acids, 1,3-diethers, and mixtures thereof.
9. Moulded article comprising nucleated propylene-butylene copolymer according to claim 1 .
10. Method for the use of the nucleated propylene-butylene copolymer according to claim 1 in medical, diagnostic, household or alimentary applications.