Polyethylene and chlorinated polyethylene thereof
The polyethylene according to the present disclosure reacts with chlorine to prepare a chlorinated polyethylene having excellent processability during extrusion with a high tensile strength by implementing a molecular structure having a high content of medium molecular weight, and may also prepare a CPE compound including the chlorinated polyethylene.
1. A polyethylene having an entanglement molecular weight of 9500 g/mol to 13000 g/mol, a melt flow rate ratio (MFRR 21.6/5 , a value obtained by dividing the melt index measured at 190° C. under a load of 21.6 kg by the melt index measured at 190° C. under a load of 5 kg in accordance with ASTM D 1238) of 16 to 25, and a molecular weight distribution (Mw/Mn) of 5.5 to 10.
2. The polyethylene according to claim 1 , wherein the polyethylene has MI 5 (a melt index measured at 190° C. under a load of 5 kg) of 0.6 g/10 min to 1.1 g/10 min.
3. The polyethylene according to claim 1 , wherein the polyethylene has a weight average molecular weight of 150000 g/mol to 200000 g/mol.
4. The polyethylene according to claim 1 , wherein the polyethylene has a density of 0.953 g/cm 3 to 0.957 g/cm 3 .
5. The polyethylene according to claim 1 , wherein the polyethylene has an elongational viscosity (210° C., 0.5 s) for cross-linked polyethylene of 750000 Pa·s or more.
6. The polyethylene according to claim 1 , wherein the polyethylene has an MDR torque (MH-ML, measured at 180° C. for 10 min) of 6.5 Nm or more.
7. A method for preparing the polyethylene according to claim 1 , comprising the step of polymerizing ethylene in the presence of at least one first metallocene compound represented by the following Chemical Formula 1; and at least one second metallocene compound selected from the compounds represented by the following Chemical Formula 3:
in Chemical Formula 1,
Q 1 and Q 2 are the same as or different from each other, and are each independently hydrogen, halogen, C 1-20 alkyl, C 2-20 alkenyl, C 2-20 alkoxyalkyl, C 6-20 aryl, C 7-40 alkylaryl, or C 7-40 arylalkyl;
A 1 is carbon, silicon, or germanium;
M 1 is a Group 4 transition metal;
X 1 and X 2 are the same as or different from each other, and are each independently halogen, C 1-20 alkyl, C 2-20 alkenyl, C 6-20 aryl, a nitro group, an amido group, C 1-20 alkylsilyl, C 1-20 alkoxy, or a C 1-20 sulfonate group; and
one of C 1 and C 2 is represented by the following Chemical Formula 2a or 2b, and the other is represented by the following Chemical Formula 2c, 2d or 2e;
in Chemical Formulae 2a, 2b, 2c, 2d and 2e, R 1 to R 31 and R 1□ to R 13□ are the same as or different from each other, and are each independently hydrogen, halogen, C 1-20 alkyl, C 1-20 haloalkyl, C 2-20 alkenyl, C 1-20 alkylsilyl, C 1-20 silylalkyl, C 1-20 alkoxysilyl, C 1-20 alkoxy, C 6-20 aryl, C 7-40 alkylaryl, or C 7-40 arylalkyl, provided that at least one of R 9 to R 13 and R 9□ to R 13□ is C 1-20 haloalkyl, or
two or more R 14 to R 31 that are adjacent to each other are connected with each other to form a C 6-20 aliphatic or aromatic ring unsubstituted or substituted with a C 1-10 hydrocarbyl group;
⋅ represents a site of binding to A 1 ; and
represents a site of binding to M 1 ;
in Chemical Formula 3,
at least one of R 32 to R 39 is —(CH 2 ) n —OR, wherein R is C 1-6 linear or branched alkyl and n is an integer of 2 to 6;
the rest of R 32 to R 39 if present are the same as or different from each other, and are each independently selected from the group consisting of hydrogen, halogen, C 1-20 alkyl, C 2-20 alkenyl, C 6-20 aryl, C 7-40 alkylaryl, and C 7-40 arylalkyl, or two or more of R 32 to R 39 that are adjacent to each other are connected with each other to form a C 6-20 aliphatic or aromatic ring unsubstituted or substituted with a C 1-10 hydrocarbyl group;
Q 3 and Q 4 are the same as or different from each other, and are each independently hydrogen, halogen, C 1-20 alkyl, C 2-20 alkenyl, C 2-20 alkoxyalkyl, C 6-20 aryl, C 7-40 alkylaryl, or C 7-40 arylalkyl;
A 2 is carbon, silicon, or germanium;
M 2 is a Group 4 transition metal;
X 3 and X 4 are the same as or different from each other, and are each independently halogen, C 1-20 alkyl, C 2-20 alkenyl, C 6-20 aryl, a nitro group, an amido group, C 1-20 alkylsilyl, C 1-20 alkoxy, or a C 1-20 sulfonate group; and
m is an integer of 0 or 1.
8. The method for preparing the polyethylene according to claim 7 , wherein the first metallocene compound is represented by the following Chemical Formula 1-1:
in Chemical Formula 1-1, Q 1 , Q 2 , A 1 , M 1 , X 1 , X 2 , R 3 , and R 9 to R 21 are the same as defined in claim 7 .
9. The method for preparing the polyethylene according to claim 7 , wherein each of the Q 1 and Q 2 is independently C 1-3 alkyl, or C 2-12 alkoxyalkyl, each of the X 1 and X 2 is independently halogen, A 1 is silicon, and M 1 zirconium or hafnium.
10. The method for preparing the polyethylene according to claim 7 , wherein each of the R 9 to R 13 and R 9′ to R 13′ is independently hydrogen, or C 1-6 haloalkyl, provided that at least one of R 9 to R 13 and R 9□ to R 13□ is C 1-6 haloalkyl.
11. The method for preparing the polyethylene according to claim 7 , wherein the R 3 is C 1-6 linear or branched alkyl.
12. The method for preparing the polyethylene according to claim 7 , wherein each of the R 14 to R 21 is independently hydrogen or C 1-20 alkyl, or two or more of the R 14 to R 21 that are adjacent to each other are connected with each other to form a C 6-20 aliphatic or aromatic ring substituted with C 1-3 alkyl.
13. The method for preparing the polyethylene according to claim 7 , wherein the second metallocene compound is represented by one of the following Chemical Formulae 3-1 and 3-2:
in Chemical Formulae 3-1 to 3-2, Q 3 , Q 4 , A 2 , M 2 , X 3 , X 4 , and R 32 to R 39 are the same as defined in claim 7 .
14. The method for preparing the polyethylene according to claim 7 , wherein each of the X 3 and X 4 is independently halogen, and M 2 is zirconium or hafnium.
15. The method for preparing the polyethylene according to claim 7 , wherein each of the R 34 and R 37 is independently unsubstituted C 1-6 alkyl or C 2-6 alkyl substituted with C 1-6 alkoxy.
16. The method for preparing the polyethylene according to claim 7 , wherein a weight ratio of the first metallocene compound and the second metallocene compound is 45:55 to 60:40.
17. The method for preparing the polyethylene according to claim 7 , wherein the polymerization is carried out while introducing 70 ppm to 120 ppm of hydrogen gas based on ethylene content.
18. The method for preparing the polyethylene according to claim 7 , wherein the second metallocene compound is represented by one of the following Chemical Formulae 3-3 to 3-2:
in Chemical Formulae 3-3 to 3-4, Q 3 , Q 4 , A 2 , M 2 , X 3 , X 4 , and R 34 to R 37 are the same as defined in claim 7 , and R′ and R″ are the same as or different from each other, and are each independently a C 1-10 hydrocarbyl group.
19. A chlorinated polyethylene prepared by reacting the polyethylene according to claim 1 with chlorine.
20. The chlorinated polyethylene according to claim 19 , wherein the chlorinated polyethylene has a Mooney viscosity (MV) measured at 121° C. of 60 or more to less than 140.