EP1358261A4 - Polypropylene for precision injection molding applications - Google Patents
Polypropylene for precision injection molding applicationsInfo
- Publication number
- EP1358261A4 EP1358261A4 EP01986103A EP01986103A EP1358261A4 EP 1358261 A4 EP1358261 A4 EP 1358261A4 EP 01986103 A EP01986103 A EP 01986103A EP 01986103 A EP01986103 A EP 01986103A EP 1358261 A4 EP1358261 A4 EP 1358261A4
- Authority
- EP
- European Patent Office
- Prior art keywords
- polypropylene
- dimethylsilandiylbis
- methyl
- article
- zirconium dichloride
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F110/00—Homopolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
- C08F110/04—Monomers containing three or four carbon atoms
- C08F110/06—Propene
Definitions
- TITLE POLYPROPYLENE FOR PRECISION INJECTION
- the present invention relates to an improved polypropylene suitable for use in precision injection molding applications, such as contact lens casting cups, and more particularly metallocene catalyzed polypropylene that is suitable for use in precision injection molding applications such as contact lens casting cups.
- Polypropylene has been used for several years for casting cups and molds, wherein a high degree of precision and accuracy in the article to be molded within the cup is desired. Such is the case with, for example, contact lens casting cups, as in US 5,843,346.
- Use of the casting cups entails placing a liquid methacrylate type of monomer in the interstice between the two halves of the polypropylene cup and polymerized to cast the contact lenses.
- Rigid, gas permeable contact lenses and bifocal contact lenses are a specific example of articles that require a very high degree of precision and accuracy in manufacturing.
- the MFR is a suitable level for injection molding, less than 100 g/10 min in one embodiment, less than 60 g/10 min in another embodiment, and less than 35 g/10 min in yet another embodiment. In one desirable embodiment, the MFR is less than 21 g/10 min, wherein the polymer desirably possesses high degree of crystallinity, and thus suitable for use in precision injection molding applications. More particularly, metallocene catalyzed polypropylenes having a relatively low MFR and desirably high degree of crystallinity are suitable for applications such as contact lens casting cups.
- Embodiments of the present invention include high-precision articles such as casting cups, the articles comprising isotactic polypropylene, the polypropylene having a MFR less than 35 g/10 min in one embodiment, and less than 21 g/lOmin in another embodiment, and a Mw/Mn value of from 1.5 to 2.5.
- the polypropylene also has a melting point of from 149°C to 159°C in one embodiment, and a crystallization temperature from 119°C to 126°C.
- the MFR of the polypropylene is from 12 to 19 g/10 min, and from 13 to 17 g/10 min in yet another embodiment.
- a nucleating agent is added to the resultant polypropylene during pelletization.
- Other additives including a primary antioxidant, a secondary antioxidant and an acid scavenger can also be added to the polypropylene.
- Embodiments of the invention also include a method of manufacturing a casting cup comprising polymerizing propylene in the presence of a metallocene catalyst system, wherein the resultant, pelletized, polypropylene has a MFR of less than 21 g/10 min.
- Additives and nucleating agents may also be added in certain embodiments.
- the metallocene catalyst system can be employed in such a fashion as to produce a polypropylene with a low MFR.
- the polypropylene having the desired MFR is typically injection molded to form the various articles. Specifically for lens casting cups, the anterior and posterior mold sections for lens casting cups are injection molded using embodiments of the polypropylene described below.
- nucleated, metallocene-catalyzed polypropylene with melt flow rates (MFR) lower than 100 g/10 min, desirably lower than 21 g/10 min, and include a nucleating agent have properties which make them useful for precision applications such as casting cups for the molding of polymerizable-articles.
- MFR melt flow rates
- One such example of a polymerizable article requiring a high degree of precision is contact lens casting cups.
- Polypropylene formulations suitable for the improved polypropylene formulation contain a nucleating agent, and optionally other additives, the polymer being made from a metallocene catalyst system (described in more detail below).
- the reaction conditions are adjusted such that the final MFR is at any level suitable for injection molding applications, for example, equal to or less than
- the dual reactor slurry polymerization process is characterized by a temperature differential between the first and second reactors.
- the reactor temperatures can be controlled in such a manner as to achieve a desirable MFR level.
- polypropylenes made from the metallocene system are characterized by having a narrow molecular weight distribution (Mw/Mn).
- polypropylene refers to a homopolymer or copolymer of propylene-derived units and at least one other ethylene and/or C 4 to C 10 ⁇ - olefin-derived unit from 0.1 to 5 wt%. More specifically, these methods produce propylene reaction products having lower MFRs and increased molecular weights in comparison to propylene reaction product polymerized under similar conditions. This is achieved in one embodiment of the invention in a two-stage slurry polymerization system having a desirably low reaction temperature and a desirable temperature differential between the stages. However, the polymer described herein may be made in a one stage or multiple stage gas, slurry, bulk, continuous, solution, or any combination thereof, phase polymerization process.
- MFR suitable for injection molding which includes contacting a metallocene catalyst system under suitable polymerization conditions with polymerizable reactants, such as propylene monomers, and recovering the propylene polymer.
- the metallocene catalyst may be a zirconium metallocene catalyst.
- the contacting step may include hydrogen.
- the hydrogen in parts per million (ppm)) may be present in the range of 100 to 50,000, and desirably from 500 to 20,000 and most desirably from 1,000 to 10,000 as measured as the gas phase concentration in equilibrium with liquid propylene at polymerization temperature.
- the polymerizable reactants may be present in the range of 90 to 99.999 wt% and desirably from 93 to 99.997 wt% and more desirably from 95 to 99.995 wt%.
- the polymer may desirably be prepared by slurry polymerization of the olefin under conditions in which the catalyst site remains relatively insoluble and/or immobile so that the polymer chains are rapidly immobilized following their formation.
- immobilization is affected, for example, by (1) using a solid, insoluble catalyst, (2) conducting the copolymerization in a medium in which the resulting copolymer is generally insoluble, and (3) maintaining the polymerization reactants and products below the crystalline melting point of the polymer.
- metallocene or metallocene supported catalyst compositions described below, and in greater detail in the Examples are desirable for polymerizing olefins.
- the polymerization processes suitable for polymerizing olefins, and particularly ⁇ -olefins, are well known by those skilled in the art and include solution polymerization, slurry polymerization, and low pressure gas phase polymerization.
- Metallocene supported catalysts compositions are particularly useful in the known operating modes employing fixed-bed, moving-bed, fluid-bed, or slurry processes conducted in single, series or parallel reactors.
- a common propylene polymerization process is one that is conducted using a two-stage slurry process in which the polymerization medium can be either a liquid monomer, like propylene, or a hydrocarbon solvent or diluent, advantageously aliphatic paraffin such as propane, isobutane, hexane, heptane, cyclohexane, etc. or an aromatic diluent such as toluene.
- the polymerization temperatures may be those considered low, for example, less than 50 °C, desirably from 0 °C to 30 °C, or may be in a higher range, such as up to about 150 °C, desirably from 50 °C up to about 80 °C, or at any ranges between the end points indicated.
- Pressures can vary from about 100 to about 700 psia (0.69-4.8 MPa). Additional description is given in US 5,274,056 and 4,182,810; and WO 94/21962.
- Pre-polymerization may also be used for further control of polymer particle morphology in typical slurry or gas phase reaction processes in accordance with conventional teachings. For example, this can be accomplished by pre-polymerizing a C 2 -C 6 ⁇ -olefin, for a limited time. The pre-polymerized catalyst is then available for use in the polymerization processes referred to above. In a similar manner, the activated catalyst on a support coated with a previously polymerized polymer can be utilized in these polymerization processes.
- polymerization poisons that may be introduced via feedstreams, solvents or diluents, by removing or neutralizing the poisons.
- monomer feed streams or the reaction diluent may be pre-treated, or treated in situ during the polymerization reaction, with a suitable scavenging agent.
- a suitable scavenging agent Typically such will be an organometallic compound employed in processes such as those using the Group- 13 organometallic compounds described in US 5,153,157; and WO-A- 91/09882 and WO-A-94/03506, noted above, and that of WO-A-93/14132.
- the "catalyst system” includes the at least one metallocene, and any activators or other compounds useful in the polymerization of olefins.
- metallocenes are detailed in US 4,530,914; 4,542,199; 4,769,910; 4,808,561; 4,871,705; 4,933,403; 4,937,299; 5,017,714; 5,026,798; 5,057,475; 5,120,867; 5,278,119; 5,304,614; 5,324,800; 5,350,723; and 5,391,790.
- Metallocenes useful in embodiments of the invention are those represented by the formula:
- M is a metal of Group 4, 5, or 6 of the Periodic Table, and are zirconium, hafnium and titanium in one embodiment, and zirconium in another embodiment.
- R i and RX are identical or different, desirably identical, and are one of the following: a hydrogen atom, a CJ-CIQ alkyl group, a C1-C3 alkyl group in another embodiment; a CJ-CJO alkoxy group, a C1-C3 alkoxy group in another embodiment; a Cg-CjQ aryl group, a Cg-Cg aryl group in another embodiment; a C ⁇ -Ci 0 aryloxy group, a C ⁇ -Cg aryloxy group in another embodiment; a C2-C10 alkenyl group, a C2-C4 alkenyl group in another embodiment; a C7-C40 arylalkyl group, a C7-C10 arylalkyl group in another embodiment; a C7-C40 alkylaryl group, a C7-C12 alkylaryl group in another embodiment; a C8-C40 arylalkenyl group, a Cg-C
- R3 and R ⁇ are hydrogen atoms.
- R-> and R" are identical or different, desirably identical, and are one of the following: a halogen atom, or a fluorine, chlorine or bromine atom in another embodiment; a CJ-CIQ alkyl group, or a C1-C4 alkyl group in another embodiment, any of which may be halogenated; a C ⁇ -Cio aryl group, which may be halogenated, or a Cg-Cg aryl group in another embodiment, which may be halogenated; a C2-C10 alkenyl group, or a C2-C4 alkenyl group in another embodiment; a C7-C40 -arylalkyl group, or a C7-C10 arylalkyl group in another embodiment; a C7-C40 alkylaryl group, or a C7-C12 alkylaryl group in another embodiment; a Cg-C4o arylalkenyl group,
- R 15 is one of a halogen atom, a chlorine atom in one embodiment; a C1 -CIQ alkyl group, a C1 -C3 alkyl group in another embodiment; a Cg-Cjo ar Y 1 g rou P > or a C ⁇ - C9 aryl group in another embodiment.
- RU, R!2 and R 3 are identical or different and are a hydrogen atom, a halogen atom, or a C1-C20 alkyl group.
- RU, Rl2 and Rl3 are a CJ-CJO alkyl group, a C1-C20 fluoroalkyl group, a CI -CJQ fluoroalkyl group in another embodiment; a C6-C30 aryl group, a C6-C20 aryl group in another embodiment; a C6-C30 fluoroaryl group, a Cg-C20 fluoroaryl group in another embodiment; a C1-C20 alkoxy group, a CJ-CJO alkoxy group in another embodiment; a C2-C20 alkenyl group, a C2-C10 alkenyl group in another embodiment; a C7-C40 arylalkyl group, a C7-C20 arylalkyl group in another embodiment; a C8-C40 arylalkenyl group, a Cg-C22 arylalkenyl group in another embodiment; a C7-C40 alkylaryl group
- ⁇ is silicon, germanium or tin, preferably silicon or germanium, most preferably silicon.
- R and R9 are identical or different and have the meanings stated for Rl 1.
- n are identical or different and are zero, 1 or 2, desirably zero or 1, m plus n being zero, 1 or 2, desirably zero or 1; and the radical
- RIO are identical or different and have the meanings stated for Rl 1, Rl2 and Rl3.
- RlO radicals can be form a ring system, desirably a ring system containing from about 4-6 carbon atoms, and can be an aromatic ring.
- Alkyl refers to straight or branched chain substituents.
- Halogen refers to fluorine, chlorine, bromine or iodine atoms, desirably fluorine or chlorine.
- Metallocenes in yet another embodiment that are useful are compounds of the structures (A) and (B):
- M ⁇ is Zr or Hf
- Rl and R ⁇ are methyl or chlorine
- R 5 , R ⁇ , R8 5 R9 5 R lu , R l 1 and R*2 have the above-mentioned meanings.
- These chiral metallocenes may be used as a racemic mixture for the preparation of highly isotactic polypropylene copolymers. It is also possible to use the pure R or S form. An optically active polymer can be prepared with these pure stereoisomeric forms. Desirably, the meso form of the metallocene is removed to ensure the center (i.e., the metal atom) provides stereoregular polymerization. Separation of the stereoisomers can be accomplished by known literature techniques. For special products it is also possible to use rac/meso mixtures.
- Illustrative but non-limiting examples of preferred metallocenes include: Dimethylsilandiylbis (2-methyl-4-phenyl- 1 -indenyl)ZrCl2 Dimethylsilandiylbis(2-methyl-4,5-benzoindenyl)ZrCl2;
- the metallocenes preferably selected for use in this invention are at least one metallocene catalyst system capable of producing isotactic, crystalline propylene polymer.
- at least one metallocene is selected from the group consisting of rac-: dimethylsilandiylbis(2- methylindenyl)zirconium dichloride; dimethylsilandiylbis(2,4- dimethylindenyl)zirconium dichloride; dimethylsilandiylbis(2,5,6- trimethylindenyl)zirconium dichloride; dimethylsilandiylbis indenyl zirconium dichloride; dimethylsilandiylbis(4,5,6,7-tetrahydroindenyl)zirconium dichloride and dimethylsilandiylbis(2-methyl-4,5-benzoindenyl)zirconium dichloride; dimethylsilandiylbis(2-methyl-4,5-benzoindenyl)zircon
- metallocenes are cyclopentadienyl complexes which have two coordinated ring systems as ligands and either alkyl groups or halides coordinated directly to the metal center.
- cyclopentadienyl complexes which have two coordinated ring systems as ligands and either alkyl groups or halides coordinated directly to the metal center.
- metallocenes such as those described in US 5,510,502. 4,931,417, 5,532,396, 5,543,373, and WO 98/014585, EP611 773 and WO 98/22486.
- the metallocenes described above, in use with the appropriate activator, can achieve molecular weights in the range of 70,000 to 150,000, in one embodiment, and from 70,000 to 280,000 in another embodiment, while the molecular weight distribution is from 1.5 to 2.5. Also, see US 5,840,644 and 5,936,053.
- Metallocenes are generally used in combination with some form of activator in order to create an active catalyst system.
- activator is defined herein to be any compound or component, or combination of compounds or components, capable of enhancing the ability of one or more metallocenes to polymerize olefins to polyolefins.
- Alklyalumoxanes are preferably used as activators, most preferably methylalumoxane (MAO).
- MAO methylalumoxane
- the alkylalumoxanes preferred for use in olefin polymerization contain about 5 to 40 of the repeating units:
- R is a Cj-Cg alkyl including mixed alkyls. Particularly preferred are the compounds in which R is methyl.
- Alumoxane solutions, particularly methylalumoxane solutions, may be obtained from commercial vendors as solutions having various concentrations.
- Ionizing activators may also be used to activate metallocenes. These activators are neutral or ionic, or are compounds such as tri(n-butyl)ammonium tetrakis(pentaflurophenyl)boron, which ionize the neutral metallocene compound. Such ionizing compounds may contain an active proton, or some other cation associated with but not coordinated or only loosely coordinated to the remaining ion of the ionizing compound. Combinations of activators may also be used, for example, alumoxane and ionizing activators in combinations, see for example, EP-B1-0 662 979.
- NCA precursors capable of activating labile non- halogen substituted metallocene compounds via ionic cationization, and consequent stabilization with a resulting non-coordinating anion include:
- trialkyl-substituted ammonium salts such as; trimethylammonium tetrakis(p-tolyl)borate, trimethylammonium tetrakis(o-tolyl)borate, tributylammonium tetrakis(pentafluorophenyl)borate, tripropylammonium tetrakis(o,p-dimethylphenyl)borate, tributylammonium tetrakis(m,m-dimethylphenyl)borate, tributylammonium tetrakis(p-trifluoromethylphenyl)borate, tributylammonium tetrakis(pentafluorophenyl)borate, tri(n-butyl)ammonium tetrakis(o-tolyl)borate and the like;
- N,N-dialkyl anilinium salts such as; N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate,
- NCA precursors include those comprising a stable carbonium ion, and a compatible non-coordinating anion. These include; triphenylcarbenium tetrakis (trifluorophenyl) borate tropillium tetrakis(pentafluorophenyl)borate, triphenylmethylium tetrakis(pentafluorophenyl)borate, benzene (diazonium) tetrakis(pentafluorophenyl)borate, tropillium phenyltris(pentafluorophenyl)borate, triphenylmethylium phenyl-(trispentafluorophenyl)borate, benzene (diazonium) phenyl-tris(pentafluorophenyl)borate, tropillium tetrakis(2,3,5,6-tetrafluorophenyl)borate, triphenylmethylium
- noncoordinating anion means an anion which either does not coordinate to said cation or which is only weakly coordinated to said cation thereby remaining sufficiently labile to be displaced by a neutral Lewis base.
- “Compatible” noncoordinating anions are those which are not degraded to neutrality when the initially formed complex decomposes. Further, the anion will not transfer an anionic substituent or fragment to the cation so as to cause it to form a neutral four coordinate metallocene compound and a neutral by-product from the anion.
- Noncoordinating anions useful in accordance with this invention are those which are compatible, stabilize the metallocene cation in the sense of balancing its ionic charge in a +1 state, yet retain sufficient lability to permit displacement by an ethylenically or acetylenically unsaturated monomer during polymerization.
- ionizing ionic compounds not containing an active proton but capable of producing the both the active metallocene cation and a noncoordinating anion. See, EP-B1-0 426 637 and EP-A3- 0 573 403.
- An additional method of making the ionic catalysts uses ionizing anion pre-cursors which are initially neutral Lewis acids but form the cation and anion upon ionizing reaction with the metallocene compounds, for example the use of tris(pentafluorophenyl) boron. See EP-B1-0 520 732.
- Ionic catalysts for addition polymerization can also be prepared by oxidation of the metal centers of transition metal compounds by anion pre-cursors containing metallic oxidizing groups along with the anion groups, see EP-B1-0 495 375.
- metal ligands include halogen moieties (for example, bis- cyclopentadienyl zirconium dichloride) which are not capable of ionizing abstraction under standard conditions, they can be converted via known alkylation reactions with organometallic compounds such as lithium or aluminum hydrides or alkyls, alkylalumoxanes, Grignard reagents, etc. See EP-A4-0 500 944 and EP- Bl-0 570 982 and US 5,434,115, for in situ processes describing the reaction of alkyl aluminum compounds with dihalo-substituted metallocene compounds prior to or with the addition of activating anionic compounds.
- organometallic compounds such as lithium or aluminum hydrides or alkyls, alkylalumoxanes, Grignard reagents, etc.
- the metallocene, activator, or both may be part of a supported catalyst system, wherein the metallocene, activator, or both are supported on an organic or inorganic matrix such as silica, alumina, or other suitable solid support.
- the support may be pretreated with such reagents as fluoriding agents or other suitable reagents that improve the support surface and increase the catalyst efficiency.
- suitable systems are disclosed in, for example, US 6,143,686, 6,228,795, 6,143,911, 5,939,347, and 5,643,847 and WO 00/12565, WO 00/25916.
- a suitable catalyst composition is a bridged 2-alkyl-4-phenyl-indenyl metallocene and at least one highly fluorinated tris-arylborane bound to a fluorided support composition, wherein the highly fluorinated tris-arylborane is selected from tris-perfluorophenyl borane, trisperfluoronaphthyl borane, trisperfluorobiphenyl borane, tris(3,5-di(trifluoromethyl)phenyl)borane, tris(di-t- butylmethylsilyl)perfluorophenylborane, and mixtures thereof, and the fluorided support composition is selected from fluorided talc, clay, silica, alumina, magnesia, zirconia, iron oxides, boria, calcium oxide, zinc oxide, barium oxide thoria, aluminum phosphate gel, polyvinylchloride or substituted polyst
- the metallocene is used in the polymerization in a concentration, based on the transition metal, of from 10 " to 10 " mol, in another embodiment from 10 "4 to 10 "7 mol, of transition metal per dm 3 of solvent or per dm 3 of reactor volume.
- alumoxane is used as the cocatalyst, it is used in a concentration of from 10 '5 to 10 "1 mol, in another embodiment from 10 "4 to 10 "2 mol, per dm 3 of solvent or per dm 3 of reactor volume.
- the other cocatalysts mentioned are used in an approximately equimolar amount with respect to the metallocene. In principle, however, higher concentrations are also possible.
- the polymerization is carried out as a suspension or solution polymerization
- an inert solvent which is customary for the Ziegler low-pressure process is typically used for example
- the polymerization is carried out in an aliphatic or cycloaliphatic hydrocarbon; examples of which are propane, butane, hexane, heptane, isooctane, cyclohexane and methylcyclohexane. It is also possible to use a benzene or hydrogenated diesel oil fraction. Toluene can also be used.
- the polymerization is preferably carried out in the liquid monomer. If inert solvents are used, the monomers are metered in gas or liquid form.
- another alkylaluminum compound such as, for example, trimethylaluminum, triethylaluminum, triisobutylaluminum, trioctylaluminum or isoprenylaluminum, may additionally be introduced into the reactor in order to render the polymerization system inert (for example to remove catalyst poisons present in the olefin).
- This compound is added to the polymerization system in a concentration of from 100 to 0.01 mmol of Al per kg of reactor contents.
- Mn and Mw molecular weight distribution
- Melt Flow Rate (MFR) of the polymers was measured according to ASTM D 1238 at 230°C, with a 2.16 kg load.
- Crystallization data were determined by differential scanning calorimetry (DSC).
- DSC differential scanning calorimetry
- the non-isothermal crystallization temperature is recorded as the temperature of greatest heat generation, typically between 100°C to 125°C.
- the area under the peak corresponds to the heat of crystallization (He).
- Embodiments of the polypropylene of the invention contain a nucleating agent, an additive specifically utilized to increase the rate of crystallization of the polymer as it cools from the melt as compared to the same polymer in the absence of such an additive.
- nucleating agents for polypropylene which would are suitable for inclusion in the polypropylene formulations of this invention. Suitable nucleating agents are disclosed by, for example, H. ⁇ . Beck in Heterogeneous Nucleating Agents for Polypropylene Crystallization, 11 J.
- nucleating agents are sodium benzoate, sodium 2,2'-methylenebis(4,6-di- tert-butylphenyl) phosphate, aluminum 2,2'-methylenebis(4,6-di-tert-butylphenyl) phosphate, dibenzylidene sorbitol, di(p-tolylidene) sorbitol, di(p- ethylbenzylidene) sorbitol, bis(3,4-dimethylbenzylidene) sorbitol, and ⁇ ', ⁇ '- dicyclohexyl-2,6-naphthalenedicarboxamide, and salts of disproportionated rosin esters.
- the foregoing list is intended to be illustrative of suitable choices of nucleating agents for inclusion in the subject polypropylene formulations, but it is not intended to limit in any way the
- additives may be included in the subject polypropylene formulations as suggested by the intended uses of the materials and the knowledge and experience of the formulator.
- included in the polypropylene formulation is a primary antioxidant to deter oxidative degradation of the polymer and an acid scavenger to neutralized acid catalyst residues which may be present in the polymer to a greater or lesser extent.
- Examples of the former class of additives would be hindered phenolic antioxidants and hindered amine light stabilizers, examples and the application of which are well documented in the art.
- additives examples include metal salts of weak fatty acids such as sodium, calcium, or zinc stearate and weakly basic, naturally occurring minerals such as hydrotalcite or a synthetic equivalent like DHT-4A (Mg 4 . 5 Al 2 (OH) 13 CO 3 -3.5H 2 0, Kiowa Chemical Industry Co., Ltd.). As elsewhere in this specification, these listings of possible additives are meant to be illustrative but not limiting of the choices which may be employ.
- a secondary antioxidant is added to the resultant polypropylene pellets to stabilize the resins to oxidative degradation during high temperature processes to which they might be subjected or during very long storage periods at somewhat elevated temperatures.
- high temperature stabilizers are organic phosphorous acid esters (phosphites) such as trinonylphenol phosphite and tris(2,4-di-t-butylphenyl) phosphite, and more recently discovered agents such as distearyl, hyroxylamine and 5,7-di-t-butyl-3-(3,4-dimethylphenyl)-3H-benzofuranone.
- the high temperature stabilizers include distearyl thiodipropionate and other fatty esters of thiodipropionic acid.
- Other agents of these types which are too numerous to list here, may likewise be utilized, but the foregoing is a representative, non-limiting list of commonly used examples.
- Many other types of additives could be optionally included in the resin formulations of this invention such as lubricants, antistatic agents, slip agents, anti-blocking agents, colorants, metal deactivators, mold release agents, fillers and reinforcements, fluorescent whitening agents, biostabilizers, and others.
- Certain metallocenes exhibit a high degree of sensitivity to the hydrogen that is in the slurry polymerization reactors. This results in producing polypropylenes having a lower limit of MFR from 22 to 100 g/10 min or more.
- the polypropylenes in the present invention may be produced in a two-stage reactor system in one embodiment: a first and a second reactor, the first at a higher temperature than the second. By lowering the temperature of the two reactors used to produce the polypropylene, lower MFRs can be achieved.
- Table 1 shows this relationship for polypropylenes produced using the metallocene catalyst system, and more particularly using a metallocene selected from the group comprising dimethylsilandiylbis(2-methylindenyl)zirconium dichloride; dimethylsilandiylbis(2,4-dimethylindenyl)zirconium dichloride; dimethylsilandiylbis(2,5,6-trimethylindenyl)zirconium dichloride; dimethylsilandiylbis indenyl zirconium dichloride; dimethylsilandiylbis(4,5,6,7- tetrahydroindenyl)zirconium dichloride and dimethylsilandiylbis(2-methyl-4,5- benzoindenyl)zirconium dichloride; dimethylsilandiylbis(2-methyl-4- phenylindenyl)zirconium dichloride; dimethylsilandiyIbis(2-methyl-4,6- diiso
- An example of one embodiment of the polypropylene formulation useful in the invention is a polypropylene synthesized using the metallocene catalyst system described above.
- the slurry polymerization process takes place in two stages, wherein the temperature of the first reactor is higher than the temperature of the second reactor, thus creating a temperature differential.
- the temperature differential between the reactors if from 1°C to 20°C, and from 2°C to 15°C in another embodiment, and in yet another embodiment the differential is from 3°C to lO°C.
- the reaction conditions during polymerization in one embodiment may be as follows: reactor temperatures to produce a finished product with a nominal 17.1 g/ lOmin MFR are 67.2°C in the lead (first) reactor and 61.7°C in the second reactor. In another embodiment, temperatures of 64.4°C in the first reactor and 58.9°C in the second reactor result in a finished product with a nominal MFR of about 13 g/10 min. In another embodiment of the invention, the polymerization takes place in two stages, the temperature of which is between 63°C and 68°C in a first reactor and between 58°C and 62°C in a second reactor.
- the metallocene used in the metallocene catalyst system is selected from the group comprising dimethylsilandiylbis(2-methylindenyl)zirconium dichloride; dimethylsilandiylbis(2,4-dimethylindenyl)zirconium dichloride; dimethylsilandiylbis(2,5,6-trimethylindenyl)zirconium dichloride; dimethylsilandiylbis indenyl zirconium dichloride; dimethylsilandiylbis(4,5,6,7- tetrahydroindenyl)zirconium dichloride and dimethylsilandiylbis(2-methyl-4,5- benzoindenyl)zirconium dichloride; dimethylsilandiylbis(2-methyl-4- phenylindenyl)zirconium dichloride; dimethylsilandiylbis(2-methyl-4,6- diisopropylindenyl)zirconium dichloride; di
- the polypropylene may be pelletized with the following additive package: DHT4A (Mg 4 . 5 Al 2 (OH) 13 CO 3 -3.5H 2 0, Kiowa Chemical Industry Co., Ltd.) present at 0.01 wt% of the entire polymer/additive mixture, Irganox 1076 (octadecyl 3-(3',5'-di-t-butyl-4'-hydroxyphenyl) propionate, CAS 2082-79-3, Ciba Specialty Chemicals) at 0.05%, Irgafos 168 (tris(2,4-di-t-butyl ⁇ henyl) phosphite, (CAS 31570-04-4, Ciba Specialty Chemicals), and sodium benzoate present at 0.040 wt%.
- DHT4A Mg 4 . 5 Al 2 (OH) 13 CO 3 -3.5H 2 0, Kiowa Chemical Industry Co., Ltd.
- Irganox 1076 octade
- the homopolymer including the additive blend has an MFR 17.1 g/10 min in one example.
- the Mw value of this homopolymer was 162,619, and the Mn value was 96,889, resulting in a Mw/Mn value (MWD) of 1.68.
- the melting point of this homopolymer is 152.6°C, and the crystallization temperature is 121.9°C.
- the addition of the nucleating agent allows an a broader range of MFR to be achieved, while maintaining a high rate of crystallization which is desirable in injection molding applications and precision articles.
- the homopolymer and additive blend may have an
- MFR in the range from less than 100 g/10 min, and less than 35 g/10 min in another embodiment, and less than 21 g/10 min in yet another embodiment, and from 12 to 19 g/10 min in yet another embodiment, and from 13 to 17 g/10 min in yet another embodiment.
- the resultant polypropylene may have an MWD of from 1.5 to 2.5.
- the melting point is from 149°C to 159°C, and in yet another embodiment from 151°C to 154°C; and the crystallization temperature is from 110°C to 128°C in one embodiment, from 119°C to 126°C in another embodiment, and from 120°C to 123°C in another embodiment.
- the crystallization temperature is from 110°C to 120°C, wherein the crystallization temperature range may be any combination of any maximum and any minimum value listed above.
- the polypropylenes of the present invention are highly isotactic.
- another feature of metallocene produced polymers useful in the present invention is the amount of amorphous polypropylene, or hexane extractables, they contain.
- the polypropylene of this invention may be characterized as having low amorphous polypropylene, less than 3% by weight in one embodiment, less than 2% by weight in another embodiment, and less than 1% by weight in yet another embodiment. In yet another embodiment, there is no measurable amorphous polypropylene.
- Embodiments of the polypropylene of the invention can be used in various high-precision articles. Examples of such articles are: contact lens casting cups, contact lens packages, micropipettes, centrifuge tubes, multi-well plates, diagnostic cuvettes, packaging for electronic data storage media including compact disks, DNDs, computer hard drives, etc, medical devices like syringes and auxiliary equipment, labware, devices manipulated by robotic equipment, and any device or article requiring accurate, precise, and stable dimensions.
- the polypropylene described herein may be formed into articles by any of a variety of processes.
- Illustrative, but not limiting, examples of the forming methods, which may be employed, are injection molding, compression molding, thermoforming, injection blow molding, injection stretch blow molding, extrusion blow molding, and extrusion.
- the most preferred method of forming of the plastic is injection molding.
Landscapes
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Transition And Organic Metals Composition Catalysts For Addition Polymerization (AREA)
- Injection Moulding Of Plastics Or The Like (AREA)
- Compositions Of Macromolecular Compounds (AREA)
Abstract
Description
Claims
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US25008500P | 2000-11-30 | 2000-11-30 | |
US250085P | 2000-11-30 | ||
PCT/US2001/046883 WO2002044260A2 (en) | 2000-11-30 | 2001-11-08 | Polypropylene for precision injection molding applications |
Publications (2)
Publication Number | Publication Date |
---|---|
EP1358261A2 EP1358261A2 (en) | 2003-11-05 |
EP1358261A4 true EP1358261A4 (en) | 2005-11-02 |
Family
ID=22946260
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP01986103A Withdrawn EP1358261A4 (en) | 2000-11-30 | 2001-11-08 | Polypropylene for precision injection molding applications |
Country Status (7)
Country | Link |
---|---|
EP (1) | EP1358261A4 (en) |
JP (1) | JP2004514775A (en) |
CN (1) | CN1478122A (en) |
AU (1) | AU2002236568A1 (en) |
CA (1) | CA2430564A1 (en) |
MX (1) | MXPA03004837A (en) |
WO (1) | WO2002044260A2 (en) |
Families Citing this family (20)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP3952797B2 (en) * | 2002-02-14 | 2007-08-01 | 住友化学株式会社 | Polypropylene resin composition |
US7807769B2 (en) * | 2002-09-20 | 2010-10-05 | Exxonmobil Chemical Patents Inc. | Isotactic polypropylene produced from supercritical polymerization process |
EP1533102A1 (en) * | 2003-11-14 | 2005-05-25 | Total Petrochemicals Research Feluy | Polypropylene processing with reduced cycle time in injection-stretch-blow moulding. |
JP4561203B2 (en) | 2004-06-30 | 2010-10-13 | セイコーエプソン株式会社 | Ink jet printer and ink jet recording method |
BRPI0513057A (en) * | 2004-07-08 | 2008-04-22 | Exxonmobil Chem Patents Inc | polymer production under supercritical conditions |
US20060051454A1 (en) * | 2004-08-26 | 2006-03-09 | Ansell Scott F | Molds for producing ophthalmic lenses |
US20090118451A1 (en) * | 2005-10-21 | 2009-05-07 | Basell Polyolefine Gmbh | Polypropylene Random Copolymers Having High Melt Flow Rates for Injection Molding and Melt Blown Applications |
CN101903150A (en) | 2007-12-20 | 2010-12-01 | 诺瓦提斯公司 | Method for cast molding contact lenses |
CN102675731A (en) * | 2011-03-10 | 2012-09-19 | 北京伊士通新材料发展有限公司 | Thermal ageing-resistant polypropylene mixture, preparation method and application thereof |
JP6309509B2 (en) * | 2012-05-22 | 2018-04-11 | ボルージュ コンパウンディング シャンハイ カンパニー リミテッド | Low warpage molded article |
JP5981310B2 (en) * | 2012-11-09 | 2016-08-31 | 株式会社Adeka | Process for producing olefin resin composition for sanitary materials |
JP5981308B2 (en) * | 2012-11-09 | 2016-08-31 | 株式会社Adeka | Method for producing nucleating agent master batch |
JP5981312B2 (en) * | 2012-11-09 | 2016-08-31 | 株式会社Adeka | Process for producing olefin resin composition |
US9243127B2 (en) | 2012-06-14 | 2016-01-26 | Adeka Corporation | Method for producing nucleator masterbatch |
JP5981309B2 (en) * | 2012-11-09 | 2016-08-31 | 株式会社Adeka | Process for producing olefin resin composition for film material and fiber material |
JP5981311B2 (en) * | 2012-11-09 | 2016-08-31 | 株式会社Adeka | Process for producing olefin resin composition |
JP2014089441A (en) * | 2012-10-02 | 2014-05-15 | Japan Polypropylene Corp | Contact lens material, contact lens molding die, contact lens case, method for manufacturing contact lens and contact lens |
US11485807B2 (en) | 2016-04-28 | 2022-11-01 | Sumitomo Chemical Company, Limited | Polypropylene resin composition, precision-injection-molded object, mold for molding optical member, and process for producing optical member |
CN107513143B (en) * | 2016-06-15 | 2019-09-20 | 中国石化扬子石油化工有限公司 | A kind of preparation method of High Impact Polypropylene |
US11992101B2 (en) | 2020-07-31 | 2024-05-28 | Johnson & Johnson Vision Care, Inc. | Nucleated polypropylene resin for primary lens package |
Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5145819A (en) * | 1990-11-12 | 1992-09-08 | Hoechst Aktiengesellschaft | 2-substituted disindenylmetallocenes, process for their preparation, and their use as catalysts in the polymerization of olefins |
EP0576970A1 (en) * | 1992-06-27 | 1994-01-05 | Hoechst Aktiengesellschaft | Metallocenes with arylsubstituted indenyl-derivatives as ligands, process for their preparation and their use as catalysts |
EP0588208A2 (en) * | 1992-09-12 | 1994-03-23 | Hoechst Aktiengesellschaft | Polyolefin moulding composition with broad melt range, process and use therefore |
US5597881A (en) * | 1992-09-11 | 1997-01-28 | Hoechst Aktiengesellschaft | Polyolefin molding composition for the production of molding of high rigidity and transparency by injection molding |
US5972251A (en) * | 1996-10-16 | 1999-10-26 | Bausch & Lomb Incorporated | Method for blocking a contact lens button |
EP0992516A2 (en) * | 1994-06-13 | 2000-04-12 | TARGOR GmbH | Transition-metal complexes |
WO2000025916A1 (en) * | 1998-11-02 | 2000-05-11 | Exxon Chemical Patents Inc. | Polymeric supported catalysts |
US6153715A (en) * | 1998-09-17 | 2000-11-28 | Idemitsu Petrochemical Co., Ltd. | Propylenic resin and blow molded article made therefrom |
-
2001
- 2001-11-08 CA CA002430564A patent/CA2430564A1/en not_active Abandoned
- 2001-11-08 WO PCT/US2001/046883 patent/WO2002044260A2/en active Application Filing
- 2001-11-08 JP JP2002546621A patent/JP2004514775A/en not_active Ceased
- 2001-11-08 EP EP01986103A patent/EP1358261A4/en not_active Withdrawn
- 2001-11-08 AU AU2002236568A patent/AU2002236568A1/en not_active Abandoned
- 2001-11-08 MX MXPA03004837A patent/MXPA03004837A/en unknown
- 2001-11-08 CN CNA018197418A patent/CN1478122A/en active Pending
Patent Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5145819A (en) * | 1990-11-12 | 1992-09-08 | Hoechst Aktiengesellschaft | 2-substituted disindenylmetallocenes, process for their preparation, and their use as catalysts in the polymerization of olefins |
EP0576970A1 (en) * | 1992-06-27 | 1994-01-05 | Hoechst Aktiengesellschaft | Metallocenes with arylsubstituted indenyl-derivatives as ligands, process for their preparation and their use as catalysts |
US5597881A (en) * | 1992-09-11 | 1997-01-28 | Hoechst Aktiengesellschaft | Polyolefin molding composition for the production of molding of high rigidity and transparency by injection molding |
EP0588208A2 (en) * | 1992-09-12 | 1994-03-23 | Hoechst Aktiengesellschaft | Polyolefin moulding composition with broad melt range, process and use therefore |
EP0992516A2 (en) * | 1994-06-13 | 2000-04-12 | TARGOR GmbH | Transition-metal complexes |
US5972251A (en) * | 1996-10-16 | 1999-10-26 | Bausch & Lomb Incorporated | Method for blocking a contact lens button |
US6153715A (en) * | 1998-09-17 | 2000-11-28 | Idemitsu Petrochemical Co., Ltd. | Propylenic resin and blow molded article made therefrom |
WO2000025916A1 (en) * | 1998-11-02 | 2000-05-11 | Exxon Chemical Patents Inc. | Polymeric supported catalysts |
Also Published As
Publication number | Publication date |
---|---|
WO2002044260A2 (en) | 2002-06-06 |
CN1478122A (en) | 2004-02-25 |
CA2430564A1 (en) | 2002-06-06 |
EP1358261A2 (en) | 2003-11-05 |
AU2002236568A1 (en) | 2002-06-11 |
MXPA03004837A (en) | 2004-01-26 |
WO2002044260A3 (en) | 2003-01-03 |
JP2004514775A (en) | 2004-05-20 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US7235618B2 (en) | Polypropylene polymers | |
WO2002044260A2 (en) | Polypropylene for precision injection molding applications | |
US5331054A (en) | Propylene copolymer composition | |
US7816456B2 (en) | Semicrystalline propylene polymer composition for producing biaxially stretched polypropylene films | |
HU214988B (en) | Multistage process for the (co)polymerization of olefins | |
KR20060006920A (en) | Supported metallocene catalysts | |
JP5140625B2 (en) | Propylene resin composition, food container using the same, and medical member | |
JP5052490B2 (en) | Crystalline polypropylene resin composition and automotive interior / exterior parts | |
US7205363B2 (en) | Polymerization processes using antistatic agents | |
JP5342922B2 (en) | Extrusion foam molding resin composition and foam using the same | |
US20040044106A1 (en) | Polypropylene for precision injection molding applications | |
JP5256102B2 (en) | Polypropylene injection blow molded body | |
CA2396670C (en) | High-molecular polypropylene with a broad distribution of the molecular weight and a short isotactic sequence length | |
JP3210039B2 (en) | Propylene copolymer composition | |
US7098277B2 (en) | Polypropylene films | |
JP5352188B2 (en) | Propylene-ethylene block copolymer production method | |
WO2023026838A1 (en) | Branched propylene-based polymer | |
JP2009173881A (en) | Propylene-ethylene block copolymer, its production method, and molded product obtained by using the same | |
JP3482700B2 (en) | Olefin polymer production catalyst and olefin polymer production method using the same | |
JP2000044738A (en) | Ethylene polymer composition |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
17P | Request for examination filed |
Effective date: 20030606 |
|
AK | Designated contracting states |
Kind code of ref document: A2 Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE TR |
|
AX | Request for extension of the european patent |
Extension state: AL LT LV MK RO SI |
|
A4 | Supplementary search report drawn up and despatched |
Effective date: 20050921 |
|
RIC1 | Information provided on ipc code assigned before grant |
Ipc: 7C 08L 23/12 B Ipc: 7C 08F 110/06 A |
|
17Q | First examination report despatched |
Effective date: 20060830 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN |
|
18D | Application deemed to be withdrawn |
Effective date: 20090417 |