Linear ethylene cyclic olefin polymer
阅读说明：本技术 线性乙烯环烯烃聚合物 (Linear ethylene cyclic olefin polymer ) 是由 杨湧 R·K·萨 于 2018-03-27 设计创作，主要内容包括：一种通过溶液聚合方法获得的聚合物,其包含0.5-20wt％的环烯烃衍生单元,0wt％-15wt％的C4-C12α-烯烃衍生单元,其余是乙烯衍生单元；并且具有：Mw/Mn小于2.5；重均分子量(Mw)是80000-300000g/mol；和g’值大于0.95。所述聚合物可以在溶液聚合方法中形成,其包括在溶液中将环烯烃、乙烯、氢气和任选的C4-C12α-烯烃与单活性位点催化剂合并来形成该聚合物,其中所述单活性位点催化剂最优选选自非对称第4族双-桥连的环戊二烯基茂金属。(A polymer obtained by a solution polymerization process comprising from 0.5 to 20 wt% of cyclo olefin derived units, from 0 wt% to 15 wt% of C4 to C12 α -olefin derived units, the remainder being ethylene derived units and having a Mw/Mn of less than 2.5, a weight average molecular weight (Mw) of 80000 and 300000g/mol, and a g' value of greater than 0.95 the polymer may be formed in a solution polymerization process comprising combining in solution a cyclo olefin, ethylene, hydrogen, and optionally a C4 to C12 α -olefin, with a single site catalyst to form the polymer, wherein the single site catalyst is most preferably selected from the group consisting of asymmetric group 4 bis-bridged cyclopentadienyl metallocenes.)
polymers comprising from 0.5 to 20% by weight of cycloolefin derived units, from 0% by weight to 15% by weight of C4-C12 α -olefin derived units, the remainder being ethylene derived units, and having:
Mw/Mn is less than 2.5;
the weight-average molecular weight (Mw) is 80 to 300 kg/mol;
g' value greater than 0.95;
at a shear rate of 0.01s-1And a complex viscosity at 190 ℃ of at least 70kPa · s; and
at a shear rate of 100s-1And a complex viscosity at 190 ℃ of less than 40kPa · s.
2. The polymer of claim 1, wherein the cyclic olefin, ethylene, and optionally C4-C12 α -olefin are combined in a solution process to form the polymer.
3. The polymer of claim 1 or 2, which exhibits rod-like morphology below the solidification temperature, with dimensions of 1-10nm width and 50-1000nm length.
4. The polymer of any of the preceding claims having a Mw/Mn ratio of from 1 to 2.5.
5. The polymer of any of the preceding claims having a z-average molecular weight of greater than 180kg/mol, alternatively from 180kg/mol to 300 kg/mol.
6. The polymer of any of the preceding having an Mz/Mw of less than 2.5.
7. The polymer of any of the preceding claims , which has a shear rate of 0.01s-1And a complex viscosity at 190 ℃ of 70 to 160kPa · s.
8. The polymer of any preceding claim , which has a shear rate of 100s-1And a complex viscosity at 190 ℃ of 40 to 5kPa · s.
9. The polymer of any of the preceding claims , which exhibits a strain rate of 0.1s-1And an extensional viscosity at 150 ℃ of at least 600kPa · s higher than LVE.
10. The polymer of any of the preceding claims , which is at 150 ℃ and 0.1s-1A Strain Hardening Ratio (SHR) at strain rate greater than 3.
11. The polymer of any of the preceding claims , wherein the cyclic olefin derived units are selected from C5-C20 olefin derived units comprising at least C5-C8 ring structures.
12. The polymer of any of the preceding claims , wherein the cyclic olefin derived units are norbornene or C1-C10 alkyl substituted norbornene derived units.
13. The polymer of any of the preceding claims , having a composition of cyclic olefin derived units and ethylene derived units.
14. The polymer of claim 2, wherein a single active site catalyst is also incorporated.
15. The polymer of claim 14, wherein the single active site catalyst is selected from the following structures:
wherein:
m is a group 4 metal;
q is silicon or carbon;
each R 'and R' is selected from the group consisting of phenyl, alkyl-substituted phenyl, and silyl-substituted phenyl;
each X is independently selected from C1-C10 alkyl, phenyl, and halogen;
R1-R8each of which is independently selected from hydrogen, C1-C10 alkyl, phenyl, and alkylphenyl; and
R1’-R6’each of which is independently selected from hydrogen, C1-C10 alkyl, and phenyl.
16. The polymer of claim 14, wherein the single active site catalyst is selected from the group consisting of:
wherein:
m is a group 4 metal;
q is silicon or carbon;
each R 'and R' is independently selected from the group consisting of phenyl, alkyl-substituted phenyl, and silyl-substituted phenyl;
each X is independently selected from C1-C10 alkyl, phenyl, and halogen;
R1-R8each of which is independently selected from hydrogen, C1-C10 alkyl, phenyl, and alkylphenyl; and
R1’-R6’each of which is independently selected from hydrogen, C1-C10 alkyl, and phenyl.
17, film having an inherent tear of greater than 500g/mil, an elongation of greater than 800%, and an MD 1% secant flexural modulus of greater than 150MPa comprising the polymer of any of the foregoing claims.
18, a thermoformed article, foamed article, or extrusion coated article comprising the polymer of any of the foregoing claims .
19, A method of forming a polymer, comprising combining in solution a cyclic olefin, ethylene, hydrogen, and optionally a C4-C12 α -olefin, with a single active site catalyst to form the polymer, wherein the single active site catalyst is selected from the following structures:
wherein:
m is a group 4 metal;
q is silicon or carbon;
each R 'and R' is selected from the group consisting of phenyl, alkyl-substituted phenyl, and silyl-substituted phenyl;
each X is independently selected from C1-C10 alkyl, phenyl, and halogen;
R1-R8each of which is independently selected from hydrogen, C1-C10 alkyl, phenyl, and alkylphenyl; and
R1’-R6’each of which is independently selected from hydrogen, C1-C10 alkyl, and phenyl;
wherein the polymer has a g' value of greater than 0.95.
20. The process of claim 19, wherein the single-site catalyst is selected from the group consisting of:
wherein:
m is zirconium or hafnium;
q is silicon or carbon;
each R 'and R' is independently selected from the group consisting of phenyl, alkyl-substituted phenyl, and silyl-substituted phenyl;
each X is independently selected from C1-C10 alkyl, phenyl, and halogen;
R1-R8each of which is independently selected from hydrogen, C1-C10 alkyl, phenyl, and alkylphenyl; and
R1’-R6’each of which is independently selected from hydrogen, C1-C10 alkyl, and phenyl.
21. The process of claim 19 or 20, wherein the polymer comprises from 0.5 to 20 wt% of cyclic olefin derived units, from 0 wt% to 15 wt% of C4-C12 α -olefin derived units, the remainder being ethylene derived units.
22. The process of claims 19-21 wherein the Mw/Mn of the polymer is less than 2.5; and the weight average molecular weight (Mw) was 80000 and 300000 g/mol.
23. The method of claims 19-22, wherein the single active site catalyst is combined with the monomer at a temperature of 80 ℃ to 150 ℃.
polymers obtained by a solution polymerization process with a single-site catalyst comprising from 0.5 to 20% by weight of cycloolefin derived units, from 0% to 15% by weight of C4-C12 α -olefin derived units, the remainder being ethylene derived units, and having:
Mw/Mn is less than 2.5;
the weight-average molecular weight (Mw) is 80 to 300 kg/mol;
the g' value is greater than 0.95.
25. The polymer of claim 24, which exhibits rod-like morphology below the freezing temperature, with dimensions of 1-10nm width and 50-1000nm length.
26. The polymer of claim 24 which is at a shear rate of 0.01s-1And a complex viscosity at 190 ℃ of at least 70kPa · s; and at a shear rate of 100s-1And a complex viscosity at 190 ℃ of less than 40kPa · s.
A film of having an inherent tear of greater than 500g/mil, an elongation of greater than 800%, and an MD 1% secant flexural modulus of greater than 150MPa, comprising a polymer comprising from 0.5 to 20 weight percent cyclic olefin derived units, from 0 weight percent to 15 weight percent C4-C12 α -olefin derived units, and the balance ethylene derived units, the polymer having:
Mw/Mn is less than 2.5;
the weight-average molecular weight (Mw) is 80 to 300 kg/mol;
g' value greater than 0.95;
at a shear rate of 0.01s-1And a complex viscosity at 190 ℃ of at least 70kPa · s; and
at a shear rate of 100s-1And a complex viscosity at 190 ℃ of less than 40kPa · s.
Technical Field
The present invention relates to linear poly (ethylene-co-cycloolefin) copolymers and linear poly (ethylene-co- α -olefin-co-cycloolefin) terpolymers having improved processability and strain hardening.
Background
Linear Low Density Polyethylene (LLDPE) is ethylene with a small amount of comonomer (usually ring C)3-C8α -olefins) short chain branching in an otherwise linear backbone imparts unique mechanical properties and processing attributes to LLDPE compared to highly branched, branched Low Density Polyethylene (LDPE) produced by high pressure free radical processes and unbranched High Density Polyethylene (HDPE) produced by low pressure metal catalyzed processes, LLDPE has been generalized as a major component of film by due to relatively low cost and its satisfactory overall mechanical properties, however, the lack of rheological properties such as shear thinning, strain hardening and melt strength causes processing difficulties in making LLDPE into a film by techniques such as blow bubble extrusion (blow bubble extrusion), or in making foamed articles.
Various schemes have been developed around combining and optimizing long chain branching structures and composition/molecular weight distributions, but the added benefit obtained is that it is commercially difficult to implement a norbornene comonomer scheme has previously been developed in US5942587 to make poly (ethylene-co- α -olefin-co-cycloolefin) terpolymers, or "cyclic olefin copolymers" (COCs). COCs produced by gas phase processes and heterogeneous catalysis have significantly improved tensile strength and modulus and ehr doff tear properties, but reduced dart drop impact.
Other references include US 5087677; US 563360; US 5629398; US 6222019; US 9321911; and US 2003/0130452.
SUMMARY
polymers obtained by a solution polymerization process comprising (or consisting essentially of, or consisting of) 0.5, or 1, or 2, or 4 to 10, or 15, or 20 wt% of cyclic olefin derived units, 0 or 1 wt% to 10 or 15 wt% of C4-C12 α -olefin derived units, the remainder being ethylene derived units, and having a Mw/Mn of less than 2.5, a weight average molecular weight (Mw) of 80000-300000g/mol, and a g' value of greater than 0.95 are provided.
Also provided are methods of forming a polymer comprising (or consisting essentially of, or consisting of) combining in solution a cyclic olefin, ethylene, hydrogen, and optionally a C4-C12 α -olefin, with a single-site catalyst to form the polymer, wherein the single-site catalyst is preferably selected from group 4 metallocenes, most preferably an asymmetric group 4 bis-bridged cyclopentadienyl metallocene.
Description of the drawings
FIG. 1 is a drawing showing an ethylene-norbornene-hexene terpolymer prepared in example 1 of the present invention1H NMR。
FIG. 2 is a drawing showing an ethylene-norbornene copolymer prepared in example 2 of the present invention1H NMR。
FIG. 3 is a Gel Permeation Chromatogram (GPC) and viscosity curve of an example of the invention.
FIG. 4 is the complex viscosity as a function of shear rate data for inventive and comparative polyethylenes.
Figure 5 is a complex viscosity plot of comparative polyethylene from US 5942587.
FIG. 6 is an extensional rheological curve for comparative and inventive polyethylenes.
FIG. 7 is an Atomic Force Micrograph (AFM) of comparative (a) and inventive polyethylenes (b) and (c).
Detailed description of the invention
The present inventors have surprisingly found that the process for making the polyethylene can affect the structure of the final product, in particular a process using a single active site catalyst, preferably selected from group 4 metallocenes, and most preferably selected from asymmetric group 4 bis-bridged cyclopentadienyl metallocenes the process for forming the polyethylene disclosed herein is a solution process, described further below, the process is characterized by having the catalyst, monomer and formed polymer dissolved in the reaction solvent, which may be an inert hydrocarbon and/or or more monomers.
As used herein, "group 4" refers to the new nomenclature of the periodic Table of the elements as disclosed in Hawley's Condensed Chemical Dictionary, 13 th edition (John Wiley & Sons, Inc. 1997).
Further, as used herein, "combining" means placing the components in in contact with each other, for example in a polymerization reactor, which under such conditions of temperature, pressure, solvent conditions, and other ambient conditions, undergoes a chemical reaction between or more monomers, typically catalyzed by the presence of a catalyst precursor and an activator.
In any embodiment, the cyclic olefin monomer combined with ethylene monomer in the polymerization process is selected from C5-C8, or C12, or C16, or C20 olefin comprising at least C5-C8 ring structures, such as, for example, a bicyclic compound such as, for example, bicyclo- (2, 3, 1) -heptene-2, preferably the cyclic olefin is selected from C5, or C6-C8, or C10, or C12, or C20 cyclic olefin, and more preferably a bicyclic olefin which is a cyclic olefin containing a bridged hydrocarbon moiety (which forms two rings throughout the structure), such as, for example, bicyclo- (2, 3, 1) -heptene-2 (norbornene), most preferably the cyclic olefin is selected from norbornene, tetracyclododecene and substituted forms thereof, for polymerization processes after combination and at a desired temperature, the components are preferably combined at least 0.8, or 1, or 2, or 3MPa, or from 0.8 or 2 or 4 MPa, or from the polymerization process at a desired temperature or temperature of the combination of the polymerization process may be carried out at a temperature in a combination reactor at a temperature of at a level of at least 0.8, or a temperature of the polymerization reactor, or a temperature of the combination of the polymerization reactor, and a temperature of the polymerization reactor, or a temperature of the reactor, and the temperature of the reactor, or temperature, which may be adjusted to achieve a combination at a level of the average temperature of the polymerization process at a temperature, or temperature, which the polymerization process at a temperature of the combination of the polymerization process at a temperature, which the combination of.
More specifically, the various monomers and catalyst precursors and activators are preferably combined in a polymerization reactor where they are allowed to react at the desired monomer concentration, catalyst concentration, temperature and pressure. In any embodiment, the contacting is conducted in a polymerization reactor having an inlet for a monomer and/or catalyst feed, and an outlet for a polymerization effluent, wherein the amount of polyethylene in the effluent is from 2 or 4 or 6 wt% to 12 or 14 or 16 or 20 wt%, based on the weight of the components in the solvent of the effluent stream. The polymerization reaction may be any type of polymerization useful for forming polyolefins such as so-called gas phase, solution or slurry reactions, preferably continuous solution, slurry or gas phase reactions.
In any embodiment, polyethylene is produced in what is commonly referred to as a "solution" process, for example, copolymerization is preferably conducted in or more single-phase, liquid-filled, stirred tank reactors with a continuous flow of feed to the system and continuous withdrawal of product under steady state conditions when more than reactors are used, which may operate in a series or parallel configuration, which produces substantially the same or different polymer components.
In any embodiment, hydrogen is also combined with the monomer and catalyst, and most preferably is present in an amount of from 4 or 5 to 20 or 25 or 30 or 40 or 50 or 100 or 200cm3/min(SCCM)。
In any embodiment, even if conducted in two or more reactors, the contacting (or polymerization) is conducted in stages or under sets of conditions to produce polyethylene.
In any embodiment, the reactors ( or more) may be maintained at a pressure that exceeds the vapor pressure of the reactant mixture to maintain the reactants in the liquid phase in this manner the reactors may be run liquid full in a homogeneous single phase.ethylene and cyclic olefin feeds (and optionally propylene, C4-C12 α -olefins and/or dienes) may be combined into streams which are then combined with a pre-cooled hexane stream.
Optional "dienes" may be added to the polymerization medium, including so-called "bi-polymerizable dienes" and "non-conjugated dienes" in any embodiment, the "bi-polymerizable dienes" are selected from vinyl-substituted strained (strained) bicyclo and non-conjugated dienes, and α -omega linear dienes, wherein the two sites of unsaturation are polymerizable by a polymerization catalyst (e.g., ziegler-natta, vanadium, metallocene, etc.), and more preferably are selected from non-conjugated vinyl norbornene and C8-C12 α -omega linear dienes (e.g., 1, 7-heptadiene and 1, 9-decadiene), and most preferably 5-vinyl-2-norbornene.
In any embodiment, a "non-conjugated diene" is a diene in which only of the double bonds are activated by the polymerization catalyst and is selected from cyclic and linear olefins, non-limiting examples of which include 1, 5-cyclooctadiene, non-conjugated dienes (and other structures in which each double bond is two carbons away from the others), norbornadiene, and other strained bicyclic and non-conjugated dienes, and dicyclopentadiene more preferably the non-conjugated diene is selected from the group consisting of C7-C30 cyclic non-conjugated dienes most preferably the non-conjugated diene is 5-ethylidene-2-norbornene.
Most preferably, dienes are not present in the polymerization process, i.e., they are not purposefully combined with the cycloalkene, ethylene, and catalyst components at any stage of the process for forming polyethylene described herein.
The flow rate can be set to maintain an average residence time in the reactor of 5 to 10 or 20min after leaving the reactor, the copolymer mixture can be quenched, series concentration steps, heat and vacuum stripping and pelletizing, or alternatively, can be fed to a subsequent reactor where another α -olefin (e.g., propylene) will copolymerize, or into a line containing a solution or slurry of polyolefin (or a combination of both) where intimate mixing can occur.
The polyethylene can be recovered from the effluent by separating the polymer from the other components in the effluent using conventional separation means. For example, the polymer may be recovered from the effluent by liquid-liquid separation or coagulation with a non-solvent such as methanol, isopropanol, acetone or n-butanol, or the polymer may be recovered by stripping the solvent or other medium with heat or steam. After removal of the solvent and monomers, the pelletized polymer may be removed from the apparatus for physical blending with the polyolefin. If in situ blending is preferred, the solvent removal is carried out after intimate mixing with the solution or slurry phase polyolefin.
The volatiles removed downstream of the liquid phase separation and the lean phase can be recycled as part of the polymerization feed in the process, degrees of separation and purification are performed to remove polar impurities or internally unsaturated olefins, which may destroy the activity of the catalyst.
There is thus provided processes for forming polyethylene comprising (or consisting essentially of, or consisting of) combining in a solution polymerization process a cyclic olefin, ethylene, hydrogen and optionally a C4-C12 α -olefin with a Single active site catalyst to form polyethylene many organometallic compounds are known to be useful Single active site Catalysts such as Metallocenes (MN), pyridyl diamide transition metal Catalysts, alkoxides and/or amide transition metal Catalysts, bis (imino) pyridyl transition metal Catalysts, and many other organometallic compounds known in the art to be useful in polyolefin Catalysis, these compounds are accompanied by activator compounds such as methylaluminoxane or boron activators, in particular perfluorinated aryl compounds these and other organometallic compounds known in the art form "Single active site Catalysts" such as those outlined below: h.kaneyoshi et al, "non metallocene-site for polyolefin" research Review (g. 431225. multidiscipline et al, "for Catalysts of synthesis", and Catalysts such as Catalysts of synthesis, pp., (r. multidiscipline pp. 755. multidiscipline pp., (r. pp. 755. dockerin. No. 2. dockerin. No.: 5. No. 5. 2. catalyst, and No. 5. see (r. 12. reaction of synthesis of metals).
Thus in any embodiment, the single-site catalyst is selected from group 4 metallocenes, most preferably asymmetric group 4 bis-bridged cyclopentadienyl metallocenes.
Even more preferably in any embodiment, the group 4 metallocene or group 4 bis-bridged cyclopentadienyl metallocene are those comprising (or consisting of) two cyclopentadienyl ligands and/or (isolobal) ligands isolobal to cyclopentadienyl groups such as those selected from the group consisting of indenyl, benzindenyl, fluorenyl, octahydrofluorenyl, cyclooctatetraenyl, cyclopentaphenanthryl, hydrogenated or partially hydrogenated versions thereof, substituted versions thereof, and heterocyclic versions thereof (preferably or two substitutions of a ring carbon to nitrogen, oxygen, sulfur, silicon and/or phosphorus).
By "asymmetric" it is meant that the two cyclopentadienyl ligands differ from each other at least in the form and character of substitution (identity), but most preferably the ring structures themselves differ.
As used herein, "substituted forms thereof" or "substituted" with respect to a hydrocarbon means that the hydrocarbon moiety may also contain C1-C6 alkyl, preferably methyl or ethyl, phenyl or other C7-C20 arene (or "aryl"), aniline, imidazole or other nitrogen heterocycle, halogen, hydroxyl, carboxylate, succinate, diol and/or thiol in place of or more hydrogens, preferably 1-2 hydrogens.
In any embodiment, at least of the two ligands are mono-or disubstituted with a group selected from C1-C12 alkyl, C3-C16 heteroalkyl, C6-C24 aryl, C9-C24 fused polycyclic aryl, C5-C20 nitrogen and/or sulfur heterocycle, and combinations thereof more preferably at least of the two ligands are mono-or disubstituted with a group selected from isopropyl, isobutyl, tert-butyl, phenyl, alkylphenyl, and dialkylphenyl.
In any embodiment, the single-site catalyst is selected from the following structure (I):
wherein M is a group 4 metal, preferably zirconium or hafnium; q is silicon or carbon; each of R 'and R' is independently selected from phenyl, alkyl-substituted phenyl, and silyl-substituted phenyl; each X is independently selected from C1-C10 alkyl, phenyl, and halogen; r1-R8Each of which is independently selected from hydrogen, C1-C10 alkyl, phenyl, and alkylphenyl; and R1’-R6’Each of which is independently selected from hydrogen, C1-C10 alkyl, and phenyl.
More preferably, the single-site catalyst is selected from the following structure (II):
wherein M is a group 4 metal, preferably zirconium or hafnium, most preferably hafnium; q is silicon or carbon, most preferably carbon; each of R' and R "is independently selected from phenyl, alkyl-substituted phenyl, and silyl-substituted phenyl, most preferably C1-C4 or C6 alkyl-silyl-substituted phenyl; each X is independently selected from C1-C10 alkyl, phenyl, and halogen; r1-R8Each of which is independently selected from hydrogen, C1-C10 alkyl, phenyl and alkylphenyl, most preferably R2And R7Is a C2-C6 linear or branched alkyl group, and the remaining R groups are hydrogen atoms; and R1’-R6’Each of which is independently selected from hydrogen, C1-C10 alkyl, and phenyl, most preferably hydrogen. In any embodiment, M in any of the above structures is hafnium, and each of R' and R "is phenyl-p-tris (C1-C6) -silyl.
The catalyst precursor must also be combined with at least activator, preferably comprising a non-coordinating borate anion and a bulky organic cation, to effect polymerization of cyclic olefin monomer and ethylene, hi any embodiment, the non-coordinating borate anion comprises a tetrakis (perfluorinated C6-C14 aryl) borate anion and substituted versions thereof, most preferably the non-coordinating borate anion comprises a tetrakis (pentafluorophenyl) borate anion or a tetrakis (perfluoronaphthyl) borate anion, preferably the bulky organic cation is selected from the following structures (IIIa) and (IIIb):
wherein each R group is independently hydrogen, C6-C14 aryl (e.g., phenyl, naphthyl, etc.), C1-C10 or C20 alkyl or substituted versions thereof, and more preferably at least R groups are C6-C14 aryl or substituted versions thereof.
In any embodiment, the bulky organic cation is a reducible lewis acid, particularly a trityl-type cation (where each "R" group in (IIIa) is an aryl group) capable of abstracting a ligand from the catalyst precursor, where each "R" group is a C6-C14 aryl group (phenyl, naphthyl, etc.) or a substituted C6-C14 aryl group, and preferably the reducible lewis acid is a triphenylcarbenium ion and substituted versions thereof.
Further, in any embodiment, the bulky organic cation is a Bronsted acid capable of donating protons to the catalyst precursor, wherein at least "R" groups in (IIIb) are hydrogen
The catalyst precursor is preferably reacted with an activator by their combination to form a "catalyst" or "activated catalyst" which can then undergo polymerization of the monomers. The catalyst may be carried out before, after or simultaneously with the monomer.
In any embodiment, the result of the polymerization reaction after combining the components is a polyethylene comprising (or consisting essentially of, or consisting of) 0.5 or 1 or 2 or 4 to 10 or 15 or 20 wt% of cyclic olefin derived units, 0 or 1 wt% to 10 or 15 wt% of C4-C12 α -olefin derived units, with the balance being ethylene derived units.
In any embodiment, the cyclic olefin derived units are selected from C5-C20 olefin derived units comprising at least C5-C8 ring structures in any embodiment the cyclic olefin derived units are norbornene or C1-C10 alkyl substituted norbornene derived units most preferably the polyethylene consists of cyclic olefin derived units and ethylene derived units.
The branching level as well as the molar mass of the polyethylene can be controlled by known means, such as adding hydrogen to the polymerization reactor when the monomers are combined with the catalyst to effect polymerization. In any embodiment, the polyethylene described herein has a number average molecular weight (Mn) of 20 or 30kg/mol to 60 or 80 or 100 or 140 kg/mol. In any embodiment, the polyethylene has a weight average molecular weight (Mw) of 80 or 100kg/mol to 120 or 140 or 160 or 200 or 300 kg/mol. In any embodiment, the z average molecular weight (Mz) is greater than 180kg/mol, alternatively 180 or 200 or 210kg/mol to 250 or 280 or 300 kg/mol. In any embodiment, the polyethylene has an Mw/Mn of less than 2.5 or 2.3 or 2.2, or an Mw/Mn value of 1 or 1.1 or 1.2 to 1.8 or 2 or 2.2, 2.3 or 2.5. In any embodiment, the Mz/Mw of the polyethylene described herein is less than 2.5 or 2 or 1.2 or 1.5 to 2 or 2.5.
In any embodiment, the polyethylene is substantially linear, meaning that there is no long chain branching (chains longer than 6 to 10 carbon atoms). Most preferably g ' (or g ') of the polyethylene 'vis) A value greater than 0.95 or 0.96 or 0.97, wherein the value "1" is invertedAn ideal linear polyethylene is reflected.
The polyethylene surprisingly exhibits improved shear thinning as reflected, for example, in having a complex viscosity that is relatively high at low shear rates and relatively low at high shear rates. This behavior produces a plot of complex viscosity versus shear rate that is nearly linear or linear with a negative slope, as shown in fig. 4. Thus, in any embodiment, the polyethylene has a shear rate of 0.01s-1And a complex viscosity at 190 ℃ of at least 70 or 80 or 90kPa · s, or of from 70 or 80 or 90kPa · s to 120 or 140 or 160kPa · s. Further, in any embodiment the polyethylene is at a shear rate of 100s-1And a complex viscosity at 190 ℃ of less than 40 or 30 or 20 or 10kPa · s, or of 40 or 30 or 20 or 10 to 5kPa · s.
The polyethylene surprisingly exhibits improved strain hardening as reflected, for example, in having an increased viscosity over time at various shear rates, such as demonstrated in fig. 6 d. Preferably the polyethylene exhibits an extensional viscosity that is detectable after a peak extensional viscosity and does not drop to zero viscosity after reaching the peak. Thus in any embodiment the polyethylene is at a strain rate of 0.1s-1And a peak extensional viscosity at 150 ℃ of at least 600 or 700 or 800 or 900kPa · s (above the linear viscoelastic limit or "LVE"), or from 600 or 700 or 800 or 900kPa · s to 1000 or 1500 or 2000kPa · s. Further, in any embodiment the polyethylene is at 150 ℃ and 0.1s-1The Strain Hardening Ratio (SHR) of the strain rate is greater than 3 or 3.2, or 3 or 3.2 to 4 or 5 or 6.
In any embodiment, the polyethylene exhibits a rod-like morphology below the solidification temperature, as evidenced, for example, by atomic force microscopy, having dimensions of 1-10nm in width and 50-1000nm in length.
The polyethylenes described herein can be used in any number of articles such as films (average thickness less than 200 μm), sheets (average thickness greater than or equal to 200 μm), molded articles (e.g., thermoformed, blow molded, extrusion molded, etc.), and pipes or tubing, any of which may be foamed or non-foamed, comprising the polyethylene, either alone as the primary polymer component or with other polymers such as propylene-based impact copolymers, ethylene-propylene-diene rubbers (EPDM), High Density Polyethylene (HDPE), other Linear Low Density Polyethylenes (LLDPE), polypropylene, polystyrene, butyl-based polymers, aryl polyester carbonates, polyethylene terephthalate, polybutylene terephthalate, amorphous polyacrylates, nylon-6, additional polyamides, polyethylene terephthalate, nylon-6, polyethylene terephthalate, polyaramids, polyetherketones, polyoxymethylenes, polyethylene oxides, polyurethanes, polyethersulfones, and polyvinylidene fluorides. Preferably the polyethylene is used alone in films, sheets, etc., or as the major component, i.e., greater than 50 or 60 or 70 or 80 weight percent of the article, based on the weight of the article.
The polyethylene described herein is particularly useful in films, particularly blown films, in any embodiment is a film having an inherent tear of greater than 500 or 550 or 600g/mil, an elongation of greater than 800 or 850 or 900%, and an
The various illustrative elements and numerical ranges disclosed herein for the polyethylenes described herein and the methods of forming the same can be combined with other illustrative elements and numerical ranges to describe polyethylenes and desirable compositions comprising the same; moreover, for a given element, any numerical upper limit described herein can be combined with any numerical lower limit, including embodiments in the jurisdiction that allow such combination. The characteristics of the polyethylene are shown in the following non-limiting examples.
Test method
Chemical structure. 500MHz NMR instrument was scanned 120 ℃ and 120 times in TCE-d2 solvent. NMR data for olefin block copolymers were prepared by dissolving 20. + -.1 mg of a sample in 0.7ml of d-solvent. The sample was dissolved in TCE-d2 in a 5mm NMR tube at 120 ℃ until the sample was dissolved. There are no standards used. TCE-d2 is the peak present at 5.98ppm and was used as the reference peak for the sample.
Mw, Mn and Mw/Mn are determined using high temperature GPC (Agilent PL-220) equipped with three in-line detectors, differential refractive index Detector (DRI), Light Scattering (LS) detectors and viscometer. the experimental details, including detector calibration, described in article 34(19) Macromolecules, 6812-column 6820 (2001) and references therein of T.Sun, P.Brant, R.R.Chance and W.W.Graessey. the nominal flow rate is 0.5mL/min and the nominal injection volume is 300 μ L. various transfer lines, columns, viscometer and differential refractometer (DRI detector) are contained in a container maintained at 145 deg.C. the solvents used for the experiment are prepared by dissolving 6g butylated hydroxytoluene as an antioxidant in 4L
c＝KDRIIDRI/(dn/dc)，
wherein KDRIIs a constant determined by correcting for DRI and (dn/dc) is the refractive index increment of the system. For at 145TCB at 690nm, refractive index n 1.500. Throughout this specification the units of reference are: in g/cm3Expressed as kg/mol or g/mol, and the intrinsic viscosity as dL/g.
The LS detector is Wyatt Technology High Temperature DAWN HELEOS. The molecular weight M at each point of the chromatogram was determined by analyzing the LS output using a Zimm model for static LIGHT SCATTERING (m.b. huglin, LIGHT SCATTERING FROM POLYMER SOLUTIONS, Academic Press, 1971):
here, Δ R (θ) is the excess Rayleigh scattering intensity measured at the scattering angle θ, "c" is the polymer concentration determined from the DRI analysis, A2Is the second virial coefficient. P (θ) is the form factor of the monodisperse random coil, and KoIs the optical constant of the system:
wherein N isAIs the Afugardro constant, and (dn/dc) is the refractive index increment of the system, which takes the same value as obtained from the DRI method. For TCB at 145 ℃ and λ 657nm, the refractive index n is 1.500.
The high temperature Viscotek Corporation viscometer (which is equipped with four capillaries arranged in a wheatstone bridge configuration, and two pressure sensors) is used to determine the specific viscosity sensors measure the total pressure drop across the detector, and another (which is located between the two sides of the bridge) measure the pressure differential the specific viscosity η s of the solution flowing through the viscometer is calculated from their outputs the intrinsic viscosity at each point of the chromatogram [ η ] is calculated from the following equation:
ηs＝c[η]+0.3(c[η])2，
where c is concentration and is determined from the DRI output.
The branching index (g' VIS) is calculated using the output of the GPC-DRI-LS-VIS method as follows.As a model, example 2 below is analyzed as EPDM (with 0 wt% propylene and 5.9 wt% ENB in EP; example 1 is analyzed as EPDM (with 6.7 wt% propylene (as a hexene substituent) and 9.3 wt% ENB (as an NB substituent) in EP.) the average intrinsic viscosity [ η ] avg of the sample is calculated as follows:
where the sum is taken from all chromatographic sections i between the integral limits.
The branching index g '(or g' vis) is defined as:
where Mv is the viscosity average molecular weight, which is based on the molecular weight determined by LS analysis. For data processing, the Mark-Houwink constants used were K0.000579 and a 0.695. The Mn value is. + -.50 g/mol, the Mw value is. + -.100 g/mol and the Mz value is. + -.200.
And (4) strain hardening. Tensile rheometry was performed on Anton-Paar MCR501 or TA Instruments DHR-3 using the SER Universal testing platform (Xpan Instruments, LLC), model SER2-P or SER 3-G. SER (Sentmanat extensional rheometer) test platforms are described in US6578413 and US 6691569. An overview of transient uniaxial extensional viscosity measurements is provided in, for example, "Strong hardening of vacuum polyolefins in uniaxial on-flow", 47(3) The Society of Rheology, Inc., J.Rheol., 619-; and "Measuring The transient extended morphology of polyethylene glycol using The SER integrative testing platform", 49(3) The Society of Rheology, Inc., J.Rheol., 585-606 (2005). Strain hardening occurs when the polymer is subjected to uniaxial stretching, and the instantaneous extensional viscosity increase is greater than would be expected from linear viscoelastic theory. Strain hardening is observed as a sudden rise in extensional viscosity in a plot of instantaneous extensional viscosity versus time. The increase in extensional viscosity is characterized by the Strain Hardening Ratio (SHR) and is defined as the maximum instantaneousThe ratio of extensional viscosity to three times the value of the instantaneous zero shear rate viscosity at the same strain. When the ratio is greater than 1, strain hardening is present in the material. The SER instrument consists of pairs of master and slave drums mounted on bearings in a chassis and mechanically linked via intermeshing gears. Rotation of the drive shaft causes the same, but opposite, rotation of the connected primary drum and the secondary drum, which causes the ends of the polymer sample to wind onto the drums, creating a stretched sample. In most cases the sample was mounted to the drum via a stationary fixture. In addition to the tensile test, the samples were also tested using transient steady state shear conditions and matched to the tensile data using a correction factor of 3. This provides a Linear Viscoelastic Envelope (LVE). A rectangular sample specimen having dimensions of approximately 18.0mm long by 12.70mm wide was mounted to the SER clamp. The samples were typically tested at 3 Hencky strain rates: 0.01s-1，0.1s-1And 1s-1. The test temperature was 150 ℃. Polymer samples were prepared as follows: the sample specimens were hot pressed at 190 ℃, mounted on a fixture, and equilibrated at 150 ℃.
Shear thinning. Small Angle Oscillation Spectroscopy (SAOS) was performed on inventive samples and samples B21-B25, and the "ECD" LLDPE (ECD-103) sample of US5942587 ("Arjunan"). The polymer samples prepared using a hot press (Carver press or Wabash press) were discs of 25mm diameter and 2.5mm thickness. To characterize the shear thinning behavior, small angle oscillatory shear measurements were performed using a rheometer ARES-G2(TA Instruments) at an angular frequency of 0.01 to 500rad/s at a temperature of 190 ℃ and at a fixed strain of 10%. The data is then converted to viscosity as a function of shear rate. To ensure that the selected strain provides a measurement within the linear deformation range, strain sweep measurements (at an angular frequency of 100Hz) have been made. Data was processed using Trios software.
Atomic Force Microscopy (AFM) is morphological imaging techniques performed using an Asylum Research Cypher atomic force microscope the sample was cryomicrotomed at-120 ℃ before scanning to produce a smooth surface after microtomed, the sample was subjected to N before evaluation2Down in the dryerAnd (4) purifying. Imaging was performed according to the following: the instrument was tuned to the fundamental (1 st) mode of the cantilever, setting the amplitude at 1.0V and the drive frequency to be about 5% below the cantilever's air-free resonant frequency. If operating in a multi-frequency mode, the higher mode (2 nd, 3 rd or 4 th depending on the cantilever and the support) is selected, setting the amplitude to 100mV and the drive frequency at resonance. The set point was set to 640mV, scan rate 1Hz, and scan angle 90. The Asylum Research reference standard (10 micron X10 micron pitch grating X200nm deep pits (deep pit) was used for AFM SQC and X, Y and Z corrections. the instrument was corrected to a precision within 2% or better of the true value of X-Y and within 5% or better of the true value of Z. the representative scan size was 500X500 nm.
All other test methods used herein are shown in table 1:
TABLE 1 test methods
Testing
Reference to
Melt index
ASTM D1238，190℃，2.16kg
Secant tensile modulus
ISO 37
Tensile strength at yield
ISO 37
Ultimate tensile strength
ISO 37
Elongation at break
ISO 37
Tear-off
ASTM D1922
Examples
All the polymers of the invention were carried out using the solution process in a 1.0L continuously stirred tank reactor (autoclave reactor) equipped with an agitator, water cooling/steam heating elements with temperature controller and pressure controller the solvent and monomer were first purified by passing through a purification column which was periodically regenerated (twice per year) or when low catalyst activity was shown to be present isohexane was used as polymerization solvent the solvent was fed into the reactor using a Pulsa pump and its flow rate was controlled by a mass flow controller the purified ethylene feed was fed to the header upstream of the reactor and its flow rate was also regulated by a mass flow controller the mixture of isohexane and tri-n-octylaluminum (TNOAL) and comonomer (1-hexene, norbornene or a mixture of both) was fed through separate lines to the same header and the combined mixture of monomer and solvent was fed into the reactor using a single tube hydrogen was added in the amounts shown in table 1 to control the molecular weight of polyethylene and to achieve the branching level of polyethylene for both examples but the molecular weight control and branching of polyethylene was also changed to 110 ℃.
The collected polymer was first placed on a boiling water vapor stage in a hood to evaporate most of the solvent and unreacted monomers and then dried in a vacuum oven at a temperature of about 90 ℃ for about 12 hours. The vacuum oven dried sample was weighed to obtain the yield. The 1-hexene content of the polymer is determined by FTIR and/or NMR, while the norbornene content of the polymer is determined by NMR. Monomer conversion was calculated using polymer yield, composition and amount of monomer fed to the reactor. Catalyst activity (also referred to as catalyst productivity) is calculated based on yield and catalyst feed rate. The entire reaction was carried out at a gauge pressure of about 2.2 MPa.
The single site catalyst used for the polymerization was p-triethylsilylphenylcarbylbis (cyclopentadienyl) (2, 7-di-t-butylfluorenyl) hafnium dimethyl and the activator used was N, N-dimethylanilinium tetrakis (pentafluorophenyl) borate both the catalyst and activator were first dissolved in toluene and the solution was maintained under an inert atmosphere.
For inventive example 1, norbornene monomer was dissolved in isohexane and the solution was purified by passing it through a bed of basic alumina while bubbling nitrogen through it. The purified norbornene was then premixed with isohexane and 1-hexene and this mixture was then fed to the reactor upstream header using a comonomer feed system. For inventive example 2, norbornene was dissolved in toluene and purified as in inventive example 1. This solution was premixed with isohexane and fed into the reactor upstream header using a comonomer feed system.
A summary of the processing conditions (Table 2) and product properties (Table 3) is given below. Ethylene derived units ("C2"), 1-hexene derived units ("C6") and norbornene derived units ("NB") are expressed as weight percentages based on the weight of the entire polyethylene.
TABLE 2 processing conditions
TABLE 3 product Properties
The polymer was characterized by NMR. The polymer productIs by proton nuclear magnetic resonance (1H NMR) spectroscopy. Terpolymer of the invention example 1 (terpolymer) and of the invention example 2 (copolymer)1The H NMR spectra are shown in fig. 1 and fig. 2, respectively. The peak in the region of 1.92 to about 2.4ppm is assigned to norbornene and is used to calculate the norbornene concentration in the polymer. The peak in the region of 0.85 to about 1.05ppm is assigned as the terminal methyl group of the 1-hexene comonomer and is used to calculate the hexene derived units concentration in the polymer.
Narrow MW distribution and linearity as determined by GPC. The GPC traces of inventive example 1 and inventive example 2 are shown in fig. 3. Both polymers exhibit a monomodal distribution and a narrow molecular weight distribution (Mw/Mn)<1.9) and g' values close to 1. Said molecular weight is related to exceptedTM1018LLDPE (Mw about 108kg/mol) was comparable.
For reference, FIG. 5 shows a plot of complex viscosity versus shear rate for some previous gas phase copolymers disclosed in US5942587 ("Arjunan"), where no significant shear thinning is observed (viscosity levels level flattens at low shear rates, rather than increasing) as compared to an Exced 1018LLDPE (FIG. 4).
And (4) strain hardening. The extensional viscosity of the polymer melt at 150 ℃ is shown in FIG. 6. Exceeded 1018LLDPE had essentially no strain hardening (fig. 6 a). The post-reactor blending scheme (low level of high ring polyethylene added) provides moderate strain hardening, but the melt is prone to fracture upon stretching (fig. 6 b). Exced 1018LLDPE contains 8 wt% hexene comonomer and
The data is summarized in Table 4. for comparison, blown films of Exced 1018LLDPE and gas phase COC terpolymer are also listed. the gas phase COC terpolymer blown films are typically 3-5 mil thick.the
TABLE 4 mechanical Properties of the films
The tensile modulus of the polyethylene of the invention (inventive copolymer 2) is twice that of excepted 1018 and shows an improvement compared to the previous gas-phase terpolymers made according to US 5942587. The yield strength was 35% higher than that of excepted 1018LLDPE and also higher than that of the gas phase terpolymer. Elongation at break was superior to that of an excepted 1018LLDPE processed in the same manner. The tear properties of the polyethylenes of the present invention are twice the inherent tear strength of the exceeded 1018LLDPE, three times the MD tear strength of the exceeded 1018LLDPE, and 70% higher than the MD tear strength of the gas phase terpolymer.
The polyethylenes of the invention also have a unique morphology, different from the excepted 1018LLDPE (fig. 7a) as shown in the bimodal AFM images of fig. 7b and 7c, both polyethylenes of the invention exhibit worm-like structures with nanometric width and 50 to about 500nm length, presumably due to assemblies rich in norbornene segments in the polymer chain, these worm-like structures are very different from the shish-kabob assemblies of the polyethylene grains of fig. 7a, instead they have alternating light and dark segments, indicating a sparsely distributed norbornene comonomer content, said worm-like assemblies being mostly located in the amorphous phase.
These results demonstrate the surprising difference of the polyethylene of the invention when made in a solution process compared to a gas phase process such as US 5942587. The polyethylenes of the present invention exhibit greater strain hardening and shear thinning than their gas phase counterparts. Thus, the polyethylene of the present invention will have improved processability and productivity in film blowing processes while maintaining or enhancing the mechanical properties of the formed film. The polyethylenes of the present invention will also provide improved melt strength which is desirable in applications such as extrusion coated and foamed articles.
In the process, the phrase "consisting essentially of" in a polymer composition or component means that no other additives, monomers and/or catalysts than those mentioned are present in the composition or process, or if present, are present in an amount no greater than 0.5 or 1.0 or 2.0 or 4.0 wt% (by weight) of the composition, and also in the process "consisting essentially of" means that there are no other major process steps affecting the formation of covalent chemical bonds between two or more moieties, such as exposure to external radiation, addition of reactive cross-linkers, further polymerization steps, etc., but there may be minor process features and changes affecting the rate of formation of the claimed covalent bonds, such as changes in, for example, temperature or pressure or concentration of the component.
For all jurisdictions in which the teaching of "incorporated by reference" is applicable, all test methods, patent publications, patents, and reference articles are hereby incorporated by reference, either in their entirety or in relevant part of their reference.
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