Injection molded article based on propylene homopolymer
View Patent ↗Injection molded article for healthcare applications based on propylene homopolymer having a melt flow rate in the range of 40 to 120 g/10 min, a pentad isotacticity of more than 92.5%, and meso sequence length of 91.0 to 160.
1. Injection molded article comprising a propylene homopolymer having
(a) a melt flow rate MFR 2 (230° C./2.16 kg) measured according to ISO 1133 in the range of 40 to 120 g/10 min;
(b) a pentad isotacticity (mmmm) of more than 92.5% determined by 13 C-NMR; and
(c) a meso sequence length (MSL4) of 91.0 to 160; MSL4 is calculated by formula (1)
MSL
4
=
2
*
[
mmmm
]
[
mmmr
]
+
4
(
1
)
wherein
“[mmmm]” is % of mmmm pentads
“[mmmr]” is % of mmmr pentads,
determined by 13 C-NMR spectroscopy.
2. Injection molded article according to claim 1 , wherein the propylene homopolymer has a meso sequence length (MSL2) of equal to or more than 65.0; MSL2 is calculated by formula (2)
MSL
2
=
2
*
[
mm
]
[
mr
]
+
2
(
2
)
wherein
“[mm]” are % of mm triads,
“[mr]” are % of mr triads,
determined by 13 C-NMR spectroscopy.
3. Injection molded article according to claim 1 , wherein the propylene homopolymer has
(a) a triad syndiotacticity (rr) of not more than 2.5% as determined by 13 C-NMR spectroscopy;
and/or
(b) a pentad isotacticity (mmmm) of more than 92.5 to 97.3% as determined by 13 C-NMR spectroscopy.
4. Injection molded article according to claim 1 , wherein the propylene homopolymer has 2,1 erythro regio-defects of equal to or below0.4 mol.-% determined by 13 C-NMR spectroscopy.
5. Injection molded article according to claim 1 , wherein the propylene homopolymer has a xylene cold soluble content (XCS) determined according ISO 16152 (25° C.) of below 4.0 wt.-%.
6. Injection molded article according to claim 1 , wherein the propylene homopolymer has a melting temperature of at least 158° C.
7. Injection molded article according to claim 1 , wherein the propylene homopolymer has a crystallization temperature of equal to or below 122° C.
8. Injection molded article according to claim 1 , wherein the propylene homopolymer is not visbroken.
9. Injection molded article according to claim 1 , wherein the propylene homopolymer has a flexural modulus measured at 23° C. according to ISO 178 of at least 1,350 MPa.
10. Injection molded article according to claim 1 , wherein the propylene homopolymer has a clarity measured according to ASTM D 1003/92 on injection molded specimen of 1 mm thickness of at least 55%.
11. Injection molded article according to claim 1 , wherein the injection molded article is a healthcare article.
12. Injection molded article according to claim 1 wherein the injection molded article is selected from the group consisting of syringes, pipette tips, and PCR equipment.
13. Injection molded article according to claim 1 , wherein the injection molded article has in its largest dimension a length of not more than 150 mm.
14. Injection molded article according to claim 1 , wherein the injection molded article has in its largest dimension a length of not more than 130 mm.
15. Injection molded article according to claim 1 , wherein the injection molded article comprises at least 75 wt.-%, based on the total weight of the injection molded article, of a propylene homopolymer having
(a) a melt flow rate MFR 2 (230° C./2.16 kg) measured according to ISO 1133 in the range of 40 to 120 g/10min;
(b) a pentad isotacticity (mmmm) of more than 92.5% determined by 13 C-NMR; and
(c) a meso sequence length (MSL4) of 91.0 to 160; MSL4 is calculated by formula (1)
MSL
4
=
2
*
[
mmmm
]
[
mmmr
]
+
4
(
1
)
wherein
“[mmmm]” is % of mmmm pentads
“[mmmr]” is % of mmmr pentads,
determined by 13 C-NMR spectroscopy.
16. Process for producing an injection molded article of claim 1 , wherein the propylene homopolymer is injection molded, wherein further said propylene homopolymer has been obtained by polymerizing propylene in the presence of
(a) a Ziegler-Natta catalyst (ZN-C) comprising compounds (TC) of a transition metal of Group 4 to 6 of IUPAC, a Group 2 metal compound (MC) and an internal donor (ID), wherein said internal donor (ID) is a non-phthalic compound;
(b) a co-catalyst (Co), and
(c) an external donor (ED).
17. Process according to claim 16 , wherein
(a) the internal donor (ID) is selected from optionally substituted malonates, maleates, succinates, glutarates, cyclohexene-1,2-dicarboxylates, benzoates and derivatives and/or mixtures thereof;
(b) the molar-ratio of co-catalyst (Co) to external donor (ED) [Co/ED] is 5 to 45.
18. Process according to claim 17 , wherein the internal donor (ID) is a citraconate.
19. Process according to claim 16 , wherein the non-phthalic compound is a non-phthalic acid ester.