Polyethylene and chlorinated polyethylene thereof
The polyethylene according to the present disclosure has a molecular structure having a narrow particle distribution and a low content of ultra-high molecular weight, so that a chlorinated polyethylene having excellent chlorination productivity and thermal stability may be prepared by reacting the polyethylene with chlorine. And, a PVC composition including the same with improved impact strength may also be prepared.
1. A polyethylene having a crystal relaxation temperature of 110° C. or more, and a relaxation time satisfying the following Equation 1:
T<− 0.6622× M+ 2 [Equation 1]
in Equation 1,
T is relaxation time of the polyethylene in seconds, and
M is a melt index (MI 5 , g/10 min) of the polyethylene measured at a temperature of 190° C. under a load of 5 kg in accordance with ASTM D 1238.
2. The polyethylene according to claim 1 , wherein the polyethylene is an ethylene homopolymer.
3. The polyethylene according to claim 1 , wherein the crystal relaxation temperature is 110° C. to 145° C.
4. The polyethylene according to claim 1 , wherein the relaxation time is 2.0 seconds or less.
5. The polyethylene according to claim 1 , wherein the melt index (MI5) is 0.55 g/10 min or less.
6. The polyethylene according to claim 1 , wherein the polyethylene has a melt flow rate ratio (MFRR21.6/5, 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 10 to 18.
7. The polyethylene according to claim 1 , wherein the polyethylene has a density of 0.947 g/cm 3 to 0.954 g/cm 3 .
8. The polyethylene according to claim 1 , wherein the polyethylene has a molecular weight distribution (Mw/Mn) of 2 to 10.
9. The polyethylene according to claim 1 , wherein the polyethylene has a content of ultra-high molecular weight that is 10 6 or more of less than 2.1%.
10. 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 of 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 when 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.
11. The method for preparing the polyethylene according to claim 10 , wherein the at least one 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 10 .
12. The method for preparing the polyethylene according to claim 10 , 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.
13. The method for preparing the polyethylene according to claim 10 , wherein the at least one second metallocene compound is represented by one of the following Chemical Formulae 3-1 to 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 10 .
14. The method for preparing the polyethylene according to claim 10 , 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.
15. The method for preparing the polyethylene according to claim 10 , wherein a weight ratio of the at least one first metallocene compound and the at least one second metallocene compound is 65:35 to 75:25.
16. The method for preparing the polyethylene according to claim 10 , wherein the polymerizing is carried out while introducing 35 ppm or less of hydrogen gas based on ethylene content.
17. A chlorinated polyethylene prepared by reacting the polyethylene of claim 1 with chlorine.
18. The chlorinated polyethylene according to claim 17 , wherein the chlorinated polyethylene has a Mooney viscosity (MV) measured at 121° C. of 85 or more to 140 or less.
19. A polyvinyl chloride (PVC) composition, comprising the chlorinated polyethylene according to claim 17 and polyvinyl chloride (PVC).
20. The PVC composition according to claim 19 , wherein the PVC composition comprises 5 wt % to 20 wt % of the chlorinated polyethylene.