Patent Application
20080033112
When a polymer or oligomer is referred to as comprising an olefin, the olefin present in the polymer or oligomer is the polymerized or oligomerized form of the olefin, respectively. The term polymer is meant to encompass homopolymers and copolymers. The term copolymer includes any polymer having two or more different monomers in the same chain, and encompasses random copolymers, statistical copolymers, interpolymers, and (true) block copolymers.
The present invention provides a polymer composition comprising:
The blend has a notched Izod impact resistance measured at 23° C. of greater than 500 J/m and a heat distortion temperature measured using a 0.46 MPa load of greater than 135° C. making the blend highly suitable for use in automotive structural applications.
The cyclic olefin first copolymer component of the present polymer composition is produced by copolymerizing at least one cyclic olefin with at least one acyclic olefin and possibly one or more dienes. The total of amount of all the cyclic olefins in the first copolymer is from about 20 to about 99 weight % of the copolymer. The residual double bonds in cyclic olefin copolymers may not have reacted or may have been hydrogenated, crosslinked, or functionalized. Cyclic olefin copolymers may have been grafted using free radical addition reactions or in-reactor copolymerizations. They may be block copolymers made using chain shuttling agents.
Cyclic olefins are defined herein as olefins where at least one double bond is contained in one or more alicyclic rings. Cyclic olefins may also have acyclic double bonds in side chains. Suitable cyclic olefins for use in cyclic olefin copolymer component include norbornene, tricyclodecene, dicyclopentadiene, tetracyclododecene, hexacycloheptadecene, tricycloundecene, pentacyclohexadecene, ethylidene norbornene (ENB), vinyl norbornene (VNB), norbornadiene, alkylnorbornenes, cyclopentene, cyclopropene, cyclobutene, cyclohexene, cyclopentadiene (CP), cyclohexadiene, cyclooctatriene, indene, any Diels-Alder adduct of cyclopentadiene and an acyclic olefin, cyclic olefin, or diene; and any Diels-Alder adduct of butadiene and an acyclic olefin, cyclic olefin, or diene; vinylcyclohexene (VCH); alkyl derivatives of cyclic olefins; and aromatic derivatives of cyclic olefins.
Suitable acyclic olefins for use in cyclic olefin copolymer component include alpha olefins (1-alkenes), isobutene, 2-butene, and vinylaromatics. Examples of such acyclic olefins are ethylene, propylene, 1-butene, isobutene, 2-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, styrene, p-methylstyrene, p-t-butylstyrene, p-phenylstryene, 3-methyl-1-pentene, vinylcyclohexane, 4-methyl-1-pentene, alkyl derivatives of acyclic olefins, and aromatic derivatives of acyclic olefins.
Dienes are defined herein broadly as including any olefin containing at least two acyclic double bonds. They may also contain aromatic substituents. If one or more of the double bonds of diene is contained in an alicyclic ring, the monomer is classified as a cyclic olefin in this invention. Suitable dienes for use in the cyclic olefin copolymer component are 1,4-hexadiene; 1,5-hexadiene; 1,5-heptadiene; 1,6-heptadiene; 1,6-octadiene; 1,7-octadiene; 1,9-decadiene; butadiene; 1,3-pentadiene; isoprene; 1,3-hexadiene; 1,4-pentadiene; p-divinylbenzene; alkyl derivatives of dienes; and aromatic derivatives of dienes.
Suitable cyclic olefin copolymers for use as the first copolymer component of the present composition include ethylene-norbornene copolymers; ethylene-dicyclopentadiene copolymers; ethylene-norbornene-dicyclopentadiene terpolymers; ethylene-norbornene-ethylidene norbornene terpolymers; ethylene-norbornene-vinylnorbornene terpolymers; ethylene-norbornene-1,7-octadiene terpolymers; ethylene-cyclopentene copolymers; ethylene-indene copolymers; ethylene-tetracyclododecene copolymers; ethylene-norbornene-vinylcyclohexene terpolymers; ethylene-norbornene-7-methyl-1,6-octadiene terpolymers; propylene-norbornene copolymers; propylene-dicyclopentadiene copolymers; ethylene-norbornene-styrene terpolymers; ethylene-norbornene-p-methylstyrene terpolymers; functionalized ethylene-dicyclopentadiene copolymers; functionalized propylene-dicyclopentadiene copolymers; functionalized ethylene-norbornene-diene copolymers; maleic anhydride grafted cyclic olefin copolymers; silane grafted cyclic olefin copolymers; hydrogenated ethylene-dicyclopentadiene copolymers; epoxidized ethylene-dicyclopentadiene copolymers; epoxidized ethylene-norbornene-dicyclopentadiene terpolymers; grafted cyclic olefin copolymers; short chain branched cyclic olefin copolymers; long chain branched cyclic olefin copolymers; and crosslinked cyclic olefin copolymers.
Cyclic olefin copolymers containing norbornene or hydrogenated dicyclopentadiene are particularly preferred. Norbornene is made from the Diels-Alder addition of cyclopentadiene and ethylene. (Cyclopentadiene is made commercially by a reverse Diels-Alder reaction starting with dicyclopentadiene). Dicyclopentadiene is a byproduct of cracking heavy feedstocks to make ethylene and propylene. Other preferred cyclic olefins are Diels-Alder adducts of cyclopentadiene with other olefins, leading to alkyl- or aryl-norbornenes, or with butadiene leading to vinylnorbornene and ethylidene norbornene. The Diels-Alder adduct of butadiene with itself leads to vinylcyclohexene, which is another preferred monomer. A preferred acyclic olefin for cyclic olefin copolymers is ethylene since ethylene-cyclic olefin copolymers have slightly better impact properties than other copolymers. Terpolymers of ethylene with norbornene and dienes containing a double bond in alicyclic rings are also preferred, because they can easily be crosslinked, grafted, or functionalized.
At least a portion of the cyclic olefin copolymer employed in the first copolymer component of the present composition has a glass transition temperatures greater than 150° C. These high glass transition temperature domains will start softening about 10-30° C. below the glass transition temperature and lead to heat distortion temperatures using a 0.45 MPa load of about 10-15° C. below their glass transition temperature and to heat distortion temperatures using a 1.80 MPa load of about 30-35° C. below the glass transition temperature. It is preferred that the glass transition temperature of at least a portion of these cyclic olefin copolymers is greater than 160° C. and more preferably is greater than 170° C. If only a portion of the cyclic olefin copolymers has a glass transition temperature greater than 150° C., it is preferable that the remaining portion has a softening point below 30° C. Such a cyclic olefin copolymer might be a block or graft copolymer with an elastomer. If a portion of the cyclic olefin copolymer has a softening point above 30° C. and below the softening point associated with the glass transition temperature above 150° C., it will tend to lower the heat distortion temperature and high temperature modulus of the composition. Cyclic olefin copolymers where all the domains have glass transition temperatures greater than 100° C. are preferred.
For automotive applications, where the present composition is to be injection molded, it is also preferred for the cyclic olefin copolymers to have high melt flow rates when measured at the processing temperatures of the injection molding machine. Melt flow rates greater than 5 ml/10 min. in the ISO 1133 test at 115° C. above the heat distortion temperature using the 1.80 MPa load are preferred.
Useful ethylene-norbornene copolymers are can be purchased from Topas Advanced Polymers and Mitsui Chemicals. Ethylene/norbornene copolymers made with metallocene catalysts are available commercially from Topas Advanced Polymers GmbH, as TOPAS copolymers. TOPAS grades 6015 and 6017 are reported to have glass transition temperatures of 160 and 180° C., respectively. Their reported heat distortion temperatures at 0.46 MPa (150 and 170° C., respectively) and at 1.80 MPa (135 and 151° C., respectively) can provide polymer compositions meeting the preferred heat distortion temperature of at least 130° C. at 0.46 MPa.
Useful cyclic-olefin copolymers can be made using vanadium, Ziegler-Natta, and metallocene catalysts. Examples of suitable catalysts are disclosed in U.S. Pat. Nos. 4,614,778 and 5,087,677.
The second polymer component of the present composition comprises one or more random, blocky, or block polymers. Each of the polymers is polymerized from at least one olefin and, possibly, at least one diene. The olefins can be either acyclic or cyclic olefins, as long as the total amount of cyclic olefin in the copolymer is less than 20 weight %. The residual double bonds in the polyolefin modifiers may not have been reacted or may have been hydrogenated, functionalized, or crosslinked. The polyolefin modifiers may have been grafted using free radical addition reactions or in-reactor copolymerizations. They may be block copolymers made using chain shuttling agents.
Acyclic olefins suitable for use in the second polymer component include alpha olefins (1-alkenes), isobutene, 2-butene, and vinylaromatics. Examples of such acyclic olefins are ethylene, propylene, 1-butene, isobutene, 2-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, styrene, p-methylstyrene, p-t-butylstyrene, p-phenylstryene, 3-methyl-1-pentene, vinylcyclohexane, 4-methyl-1-pentene, alkyl derivatives of acyclic olefins, and aromatic derivatives of acyclic olefins.
Cyclic olefins suitable for use in the second polymer component include norbornene, tricyclodecene, dicyclopentadiene, tetracyclododecene, hexacycloheptadecene, tricycloundecene, pentacyclohexadecene, ethylidene norbornene (ENB), vinyl norbornene (VNB), norbornadiene, alkylnorbornenes, cyclopentene, cyclopropene, cyclobutene, cyclohexene, cyclopentadiene (CP), cyclohexadiene, cyclooctatriene, indene, any Diels-Alder adduct of cyclopentadiene and an acyclic olefin, cyclic olefin, or diene; and Diels-Alder adduct of butadiene and an acyclic olefin, cyclic olefin, or diene; vinylcyclohexene (VCH); alkyl derivatives of cyclic olefins; and aromatic derivatives of cyclic olefins.
Dienes suitable for use in the second polymer component include 1,4-hexadiene; 1,5-hexadiene; 1,5-heptadiene; 1,6-heptadiene; 1,6-octadiene; 1,7-octadiene; 1,9-decadiene; butadiene; 1,3-pentadiene; isoprene; 1,3-hexadiene; 1,4-pentadiene; p-divinylbenzene; alkyl derivatives of dienes; and aromatic derivatives of dienes.
Suitable acyclic olefin copolymers for use as the second polymer component of the present composition include high density polyethylene (HDPE); low density polyethylene (LDPE); linear low density polyethylene (LLDPE); isotactic polypropylene (iPP); atactic polypropylene (aPP); syndiotactic polypropylene (sPP); poly(1-butene); poly(isobutylene); butyl rubber; poly(butadiene); poly(3-methyl-1-pentene); poly(4-methyl-1-pentene); poly(1-hexene); semi-crystalline ethylene-propylene copolymers; amorphous ethylene-propylene copolymers; semi-crystalline propylene-ethylene copolymers; semi-crystalline copolymers of ethylene with alpha olefins; semi-crystalline copolymers of ethylene with isobutylene or 2-butene; semi-crystalline copolymers of ethylene with vinylaromatics; semi-crystalline copolymers of ethylene with dienes such as hexadiene, vinylcyclohexene, and 7-methyl-1,6-octadiene; semi-crystalline copolymers of propylene with alpha olefins; semi-crystalline copolymers of propylene with vinyl aromatics; semi-crystalline copolymers of propylene with vinyl aromatics; semi-crystalline copolymers of propylene with isobutene or 2-butene; semi-crystalline copolymers of propylene with dienes; in reactor blends of isotactic polypropylene with ethylene-propylene rubber or ethylene-propylene-diene terpolymers (ICPs); amorphous ethylene copolymers with alpha olefins, vinyl aromatics, cyclic olefins, isobutene, 2-butene, or dienes; terpolymers of ethylene, alpha olefins including propylene, and dienes; terpolymers of ethylene, alpha olefins, and vinyl aromatics; terpolymers of ethylene, alpha olefins, and cyclic olefins; polyolefins grafted to polystyrene; polyolefins grafted to cyclic olefin copolymers; polyolefins grafted to other polyolefins; terpolymers of propylene, another olefin, and dienes; amorphous copolymers of isobutene with isoprene; amorphous copolymers of isobutene and p-methylstyrene; polyolefins with double bonds that have been hydrogenated; polyolefins with double bonds that have been epoxidized or hydroxylated; polyolefins with double bonds that have been functionalized by electrophilic additions; any functionalized polyolefin; polyolefins with short and long chain branches, polyolefins which have been crosslinked through their double bonds; polyolefins which have been crosslinked through functional groups; and polyolefins that have been grafted using free radical addition reactions. Preferred second copolymers include ethylene propylene rubbers (EP rubbers). The term “EP rubber” means a copolymer of ethylene and propylene, and optionally one or more diene monomer(s)(as described above), where the ethylene content is from 25 to 80 wt %, the total diene content is up to 15 wt %, and the balance is propylene.
At least a portion of the second polymer component should have a glass transition temperature below −30° C. These low glass transition temperature domains of the modifier remain ductile down to their glass transition temperatures and improve the low temperature notched Izod impact resistance and low temperature instrumented impact energy to the present composition. Preferably, the glass transition temperature of at least a portion of the polyolefin modifier is less than −40° C., more preferably less than −50° C. Preferably, all portions of the polyolefin modifier have these low glass transition temperatures and are available to toughen the brittle cyclic olefin copolymer phases.
In addition, the second polymer component should contain no portion with a softening point above 30° C., and preferably, above 10° C. A softening point above 30° C. is due to a glass transition temperature above 30° C. or a melting temperature of a significant portion of the modifier above 30° C. They are detectable as transitions or peaks in a differential scanning calorimeter (DSC), a Vicat softening point, a softening point in a thermal mechanical analyzer (TMA), or a sudden loss of modulus of the polyolefin modifier in a differential mechanical thermal analysis (DMTA) experiment. They are undesirable because the softening modifier also leads to a detectable softening and a lowered high temperature modulus for the composition.
The cyclic olefin first copolymer used in present composition has a very high glass transition temperature and must, therefore, be processed at even higher temperatures. The second polymer modifier used in the composition must be stable at these high processing temperatures. It is therefore preferred that the modifier contains one or more anti-oxidants effective at stabilizing the modifier at these high processing temperatures. It is also preferred that the modifier contains a UV stabilizer to prevent damage during end use applications. Most preferred are polyolefin modifiers that contain no groups that are reactive at the processing temperatures used to blend and form the present compositions.
In order for the second polymer modifier to effectively toughen the brittle cyclic first copolymer, it is desirable that the domain size of the second copolymer is less than 1-2 μm, more preferably less than 1.0 μm, in average diameter. These small domains can be achieved, when the interfacial energy between the second polymer and the brittle cyclic olefin copolymer is very small, or is even zero. Minimal interfacial energy between two phases means that breaking a large domain up into smaller domains with more interfacial area is thermodynamically allowed. Compositions with very small or zero interfacial energies can be effectively mixed, and the polyolefin modifiers dispersed, by applying shear to the melted mixture. In order to achieve toughening for a cyclic olefin copolymer, the polyolefin modifier preferably has a zero or low interfacial energy with the first copolymer. According to Souheng Wu in Polymer Interface and Adhesion, Marcel Dekker, 1982, zero or low interfacial energies are achieved when the polarity of the polyolefin modifier and cyclic olefin copolymer are matched.
To match the polarities experimentally, surface energies or solubility parameters need to be measured for each polyolefin modifier and each cyclic olefin copolymer. Surprisingly, it has been found that determining Bicerano solubility parameters can quickly narrow the candidate polyolefin modifiers for a given target cyclic olefin copolymer. D. W. Van Krevelen in Properties of Polymers, Their Correlation With Chemical Structure; Their Numerical Estimation and Prediction From Additive Group Contributions, Elsevier, 1990 developed correlations between the functional groups present in a polymer chain and its experimental solubility parameter. These correlations worked fairly well but were limited to the set of polymers containing only the functional groups used in the original correlations. Jozef Bicerano extended these correlations in Prediction of Polymer Properties, 3rd Edition, Marcel Dekker, 2002, by replacing correlations with functional groups with correlations with graph theory indices. Graph theory indices depend only on how the polymer repeat units are bonded together and on the elements present in the repeat units. They can be calculated for any repeat unit and correlated well with solubility parameters. Bicerano has tabulated Bicerano solubility parameters for 121 common polymers in Table 5.2 of his book. These equations have also been programmed into the Synthia module of the Cerius2 molecular modeling software package available from Accelerys. Using these Bicerano solubility parameters for both the cyclic olefin copolymers and polyolefin modifiers used in the ensuing Examples, the compositions with the highest room temperature notched Izod impact resistance always occur when the Bicerano solubility parameter of the polyolefin modifiers are between 0.0 and 0.6 J0.5/cm1.5 less than the Bicerano solubility parameters of the cyclic olefin copolymers. See
Preferred polyolefins can be purchased from ExxonMobil Chemical Company under the trade names Vistalon, Exxelor, Exact, or Vistamaxx, or they may be polymerized using vanadium, Ziegler-Natta, or metallocene catalysts by methods well known in the art.
Preferred EP rubbers useful as the second polymer in the compositions described herein include those having one or more of the following properties:
Particularly preferred EP rubbers for use herein contain no diene (i.e., an ethylene-propylene copolymers). If diene is present (i.e., an ethylene-propylene-diene terpolymer), preferably the diene is a norbornene-derived diene such as ethylidene norbornene (ENB), vinylidene norbornene (VNB), or dicyclopentadiene (DCPD). Diene content is measured by ASTM D 6047.
The method of making the EP rubber is not critical, as it can be made by slurry, solution, gas-phase, high-pressure, or other suitable processes, through the use of catalyst systems appropriate for the polymerization of polyolefins, such as Ziegler-Natta catalysts, metallocene catalysts, other appropriate catalyst systems or combinations thereof.
In a particularly preferred embodiment, the EP rubbers useful herein are produced using a vanadium-based catalyst system in a solution or slurry process. In another embodiment, the EP rubbers useful herein are produced using a metallocene-based catalyst system in a solution or slurry process. In yet another embodiment, the EP rubbers useful herein are produced using any single-sited catalyst system in a solution or slurry process. Preferably, the EP rubbers made by a vanadium, metallocene, or other single-sited catalyst system has a molecular weight distribution (Mw/Mn) of 1.8 to 2.5.
EP rubbers that are useful in this invention include those available from ExxonMobil Chemical (sold under the Vistalon™ tradename), including:
Many additives may be incorporated in the present polymer composition in addition to the cyclic first copolymer component and the acyclic second copolymer component. Some additives aid in the processing of molded parts; others are added to improve the stability or aesthetics of molded parts. Useful additives include lactones, hydroxylamines, phosphates, clarifying agents, hindered amine anti-oxidants, aromatic amine anti-oxidants, hindered phenol anti-oxidants, divalent sulfur anti-oxidants, trivalent phosphorus anti-oxidants, metal deactivator anti-oxidants, heat stabilizers, low profile additives, UV stabilizers, lubricants, mold release agents, odorants, antistatic agents, antimicrobial agents, slip agents, anti-blocking agents, anti-foaming agents, blowing agents, anti-fogging agents, titanates, flame retardants, dyes, and colorants. Anti-oxidants and titanates are used in some of the compositions of this invention. Preferred anti-oxidant additives are Irganox 1010, Capow L-12/H, and Irgafos 168 combined with FS-042. Irganox 1010, Irgafos 168, and FS-042 are available from Ciba. Capow L-12/H is a titanate available from Kenrich.
Processing oils can be added in compounding to improve the moldability of the present composition. Plasticizers are added to polymers to lower their glass transition temperatures and to improve impact properties For example, processing oils could be added to the polyolefin modifiers to further lower their glass transition temperatures. Useful processing oils and plasticizers for the compositions of this invention include poly(1-decene), aliphatic petroleum distillates, aromatic petroleum distillates, alicyclic petroleum distillates, wood byproducts, natural oils, and synthetic oils.
In another embodiment, plasticizers such as those described as non-functional plasticizers (NFP's) in WO 04/014998 at pages 9 to 28, particularly pages 16 line, 14 to page 20, line 17) are added to the compositions of this invention.
Crosslinking agents can also be added to the present composition to vulcanize the second copolymer component, to create grafts between the cyclic olefin first copolymers and the second copolymer, to functionalize either the cyclic olefin copolymer or the second copolymer, and to cure the composition into a thermoset. Useful crosslinking agents include hydrogen peroxide, alkylhydroperoxides, diacylperoxides, dialkylperoxides, peracids, peresters, sulfur with and without accelerators, zinc with benzothiazole acceleration, phenolic resin curatives, silanes with Pt catalysts or free radical initiators, benzoquinone derivatives, bismaleimides, and metal oxides.
The present composition can be prepared by any one of the following methods:
1. Melt blending of a preformed cyclic olefin copolymer (also referred to as the first copolymer), a preformed polyolefin modifier (also referred to as the second copolymer), and any other components in a mixer such as a Braebender Plasticorder or a Banbury mixer or in an extruder. A preferred method is a twin screw extruder with a high mixing intensity.
7. Polymerization of both the polyolefin modifier and the cyclic olefin copolymer in the same reactor using two or more catalysts, possibly followed by extrusion or melt mixing to add other components. A chain shuttle agent may or may not be used to make block copolymers in this type of polymerization.
8. Polymerization where the second double bond of a diene in the polyolefin modifier or the cyclic olefin copolymer is partially incorporated into other chains of the same type by the polymerization catalyst, leading to long chain branched or gelled polyolefin modifiers or cyclic olefin copolymers.
9. Polymerization where the second double bonds of a diene in the polyolefin modifier or cyclic olefin copolymer is incorporated into chains of other types of polymers by the polymerization catalyst leading to graft copolymers between different polyolefin modifiers, different cyclic olefin copolymers, or between a polyolefin modifier and cyclic olefin copolymer.
10. Crosslinking where an agent is added during mixing to crosslink a second double bond of either the polyolefin modifiers or the cyclic olefin copolymers with other double bonds in the composition, typically leading to long chain branched or gelled polyolefin modifiers or cyclic olefin copolymer and/or grafts between polyolefin modifiers, between cyclic olefin copolymers, or between polyolefin modifiers and cyclic olefin copolymers.
11. Functionalization where the second double bonds of dienes in either cyclic olefin copolymers or polymer modifiers or both are functionalized after the cyclic olefin copolymers and polymer modifiers are already mixed together by one of the preparation methods 1 through 9.
12. Compositions containing functionalized polyolefin modifiers or cyclic olefin copolymers made by preparation methods 1, 2, or 11, which are crosslinked as described in preparation methods 8-10, except that reaction occurs between the functional groups instead of a second double bond.
The present polymer composition has many outstanding properties, including a room temperature (23° C.) notched Izod impact resistance at 23° C. greater than 500 J/m, such as greater than 550 J/m for example greater than 600 J/m, even greater than 700 J/m. In these tests no breaks are observed. The composition also has no breaks in notched Izod impact tests at −18° C. and exhibits an impact resistance at this temperature of greater than 50 J/m. such as greater than 150 J/m, for example greater than 300 J/m, even greater than 500 J/m.
In instrumented impact tests the composition has only ductile failures at room temperature and at −29° C. and in particular exhibits instrumented impact energy measured at 23° C. of greater than 25 J, even greater than 30 J and an instrumented impact energy measured at −29° C. of greater than 25 J, even greater than 30 J. These impact properties are comparable to polycarbonates, ABS, poly(methylmethacrylate), and the best high impact polypropylene blends.
However, the heat distortion temperature of the present composition, using both 0.45 and 1.80 MPa loads, is much higher than can be achieved with toughened polypropylene blends. In particular, the present polymer composition exhibits a heat distortion temperature measured using a 0.46 MPa load of greater than 150° C., typically greater than 165° C. and a heat distortion temperature measured using a 1.80 MPa load of greater than 115° C., typically greater than 130° C., even greater than 145° C.
Moreover, the flexural modulus (1% secant method) of the composition is greater than 1200 MPa, such as greater than 1600 MPa, for example greater than 2000 MPa, even greater than 2500 MPa, which is significantly higher than that of current high impact polypropylene TPOs. (See
Articles can be formed using the present composition by injection molding, compression molding, transfer molding, reaction injection molding, thermoforming, pressing, rotational molding, blow molding, extrusion, extrusion covering, co-extrusion with other polymers, pultrusion alone or with other polymeric materials, lamination with other polymers, coating, fiber spinning, film blowing, film casting, calendaring, or casting. Articles can also be made by any of these methods, where double bonds remaining in the polyolefin modifier or cyclic olefin copolymer or their functional groups are crosslinked after the articles are formed either thermally or with one of the crosslinking agents.
The present polymer composition opens up many new applications for cyclic olefin copolymers. Since the present composition overcomes or alleviates the problem with brittleness of cyclic olefin copolymers, it can be used in most of the applications where other engineering thermoplastics are used. The present teachings can be used to make toughened, reinforced, compositions with all types of cyclic olefins and represents a major step forward for these materials.
The polymer compositions described herein are specifically useful for the fabrication of parts of an automobile including:
1. Chassis, mechanics and under the hood applications including gas tanks; bumpers beams; bumper energy absorbers; bumper fascias; grille opening reinforcements; grille opening panels; front end fascia and grilles; front end modules; front end carriers; bolsters; valve covers; rocker arm covers; cylinder head covers; engine covers; engine splash shields; engine timing belt covers; engine air cleaners; engine oil pans; battery cases and trays; fluid reservoirs; cooling system components including cooling fans and shrouds and supports and radiator supports and end tanks; air intake system components; air ducting; wheel covers; hub caps; wheel rims; suspension and transmission components; and switches and sockets.
2. Interior applications including parts of instrument panels (IP) including IP carriers and retainers, IP basic structures, IP uppers, IP lowers, and IP instrument clusters; air bag housings; interior pedals; interior consoles including center and overhead consoles and console trim; steering column housings; seat structures including seat backs and pans; interior trim including pillar trim, IP trim, and door trim panels; liftgate and hatch inner panels; door and window handles; HVAC housing; load floors; trunk liners; storage systems; package trays; door cores and door core modules.
3. Body applications including underbody panels and streamlining; rocker panels; running boards; pickup boxes; vertical body panels including fenders, quarter panels, liftgate and hatch outer panels, and door outer panels; horizontal body panels including hoods, trunks, deck lids, and roofs and roof modules; spoilers; cowl vent leaf catchers, grilles, and screens; spare wheel wells; fender liners; exterior trim; exterior door handles; signal lamp housings; head and rear lamp housings; and mirror housings.
The polymer compositions described herein can also be used to fabricate parts similar to those listed for automobiles but for heavy trucks and mass transit vehicles, such as buses, trains, and airplanes, as well as for recreational vehicles such as snowmobiles, all-terrain vehicles, sailboats, powerboats, and jet skis. Other uses for the polymer compositions described herein include the fabrication of (a) recreational goods such as toys, helmets, bicycle wheels, pool equipment housings, and rackets; (b) parts for large consumer appliances, such as washing machine tubs, refrigerator interior liners, and appliance exterior housings; (c) housings for business machines, hand tools, laboratory instruments, electronic equipment, small machinery and appliances; (d) parts for furniture; (e) structural elements in residential and commercial building and construction such as exterior panels and curtain walls, window and door frames, fascia and soffits, shutters, and HVAC components; and (f) fabricate large waste management containers.
This invention further relates to:
1. A polymer composition comprising:
In the foregoing description, the Examples and the claims, the following test methods are employed to measure the various parameters identified.
Heat distortion temperatures (HDT) were measured using ASTM methods D648-06 and D1525-00. Before testing, the samples were conditioned for at least 40 hours @ 23° C.±2° C. and 50%±5% humidity. ASTM test bars were 0.125″ thick×5″ wide×5″ length.
Density or specific gravity was measured using ASTM D972-00 Method A. Specimens were cut with a clipper belt cutter from the center portion of standard flexular modulus test samples. The length of the samples were approximately 3½ inches. Before testing, the samples were conditioned at 23±2° C. and 50±5% relative humidity for a minimum of 40 hours.
Maximum tensile stress, tensile Young's modulus, and tensile energy at break were measured using ASTM method D638-03. At least five specimens per sample were tested. Before testing, the samples were conditioned for 40 hours at 23° C.±2° C. and 50%±5% relative humidity in bags.
Flexural Young's modulus, flexural modulus at 1% tangent, and flexural modulus at 1% secant were collected according to ASTM method D790-03. At least five specimens per sample were tested. Before testing, the samples were conditioned for 40 hours at 23° C.±2° C. and 50%±5% relative humidity in bags.
Room temperature (23° C.) and low temperature (−18° C.) notched Izod were measured according to ASTM method D256-06. The test specimens were 2.5 inches long, 0.5 inches wide, and 0.125 inches thick. At least five specimens were cut using a clipper belt cutter from the uniform center of Type I tensile bars. Samples were notched using a TMI Notching cutter. Samples were conditioned at 23±2° C. and 50±5% relative humidity for a minimum of 40 hours after cutting and notching. For sub-ambient testing, notched test specimens were conditioned at the specified test temperature for a minimum of one hour before testing. The types of break observed in the notched Izod impact tests are coded as follows:
Instrumented impact at room temperature, −18° C., and −29° C. were measured according to ASTM method D3763-02. Standard test specimens are 4.0 in. diameter disks. A minimum of five specimens were tested for each sample at each temperature. Before testing, samples were conditioned at 23±2° C. and 50±5% relative humidity for a minimum of 40 hours. If high or low temperature testing was performed, the specimens to be tested were conditioned for 4 hours prior to testing. The types of breaks observed in the instrumented impact tests are coded as follows:
The 60 degree gloss measurements used ASTM method 523-89. Samples were free of dust, scratches or finger marks.
Rockwell hardness was measured using ASTM 785-03 procedure A and ASTM 618-05. Samples were conditioned at 23±2° C. and 50±5% relative humidity for a minimum of 40 hours. The standard test specimens were at least 6 mm (¼ in.) thick.
Melt flow rates at 230 C and 300 C were measured according to ASTM method D1238-04c.
Shore A and D hardness were collected using ASTM method D2240-05. The test specimens were at least 6 mm (0.25 inches) thick.
All molecular weights are number average unless otherwise noted.
Bicerano solubility parameters were determined by the Van Krevelen method described in chapter 5 of Jozef Bicerano's Prediction of Polymer Properties, 3rd Edition, Marcel Dekker, Inc., 2002. A programmed version of this estimation method was used in the example tables. It is available in the Polymer Module of the molecular modeling software package, Cerius2, version 4.0, available from Accelrys, Inc.
The invention will now be more particularly described with reference to the following non-limiting Examples.
The following materials were used in Examples:
The compression molded samples were melt mixed at 230° C. in a Braebender Plasticorder in 40 gram batches. Test samples were compression molded at 215° C. using a Wabash press.
The injection molded blends were melt mixed at 230° C. in a Warner-Pflider WP-30 mm twin screw extruder. A total of ten pounds of ingredients were added through the throat of the extruder. The first two pounds were discarded. Test samples were fabricated at 250° C. using a 110 ton Van Dorn injection molding machine. The first 15 shots were discarded.
Compression molded flexural bars were prepared from mixtures of 80 wt % of TOPAS 6015 with 20 wt % of each of the elastomers listed in Table 1. The bars were used for flexural tests and were cut for use in notched Izod impact tests at room temperature and −18° C. and heat distortion tests at 1.80 MPa. The results of the tests are presented in
The data show that the best toughening (highest notched Izod impact) occurs with Vistalon 8600, which is a non-crystalline ethylene-propylene-ethylidene norbornene random terpolymer containing 8.9 wt. % ethylidene-norbornene. Of the elastomers tested, only the Vistalon 8600 compression molded sample had more than 500 J/m impact resistance. Apparently, the high glass transition temperature ethylene/norbornene copolymers, such as Topas 6015, need a slightly polar elastomer for good impact properties. The slight polarity of Vistalon 8600 comes from its high diene content.
To assess the effect of elastomer polarities in blends with Topas 6015 or Topas 6017, Bicerano solubility parameters have been determined for most of the polymers tested in the above Examples. The Bicerano solubility parameters for Topas 6015 and Topas 6017 were determined using 53 and 58 mole % norbornene content, respectively. Both Topas polymers have an Bicerano solubility parameter value of 16.88 J0.5/cm1.5. The Bicerano solubility parameter differences in Tables 1 and 2 are calculated by subtracting the Bicerano solubility parameter for the elastomers from this value.
Room temperature notched Izod impact resistance's are plotted against differences in Bicerano solubility parameters (noted as Est. Sol. Param.) in
The results summarized in Tables 1 and 2 and
The heat distortion temperature (HDT) at 1.80 MPa of the sample obtained in Example 2 is significantly higher than can be achieved with Topas 6013, because Topas 6015 has a 20° C. higher glass transition temperature than Topas 6013. This HDT is also much higher than can be achieved with blends of polypropylenes.
The blend with the maleic anhydride grafted amorphous ethylene copolymer in Comparative Example 8 gave very poor impact toughness. Apparently, only a narrow range of elastomer polarities matches the polarity of the Topas cyclic olefin copolymers and leads to a high notched Izod impact resistance. The Bicerano solubility parameter difference for the elastomer in Comparative Example 8 could not be calculated due to a lack of exact compositional information.
Compression molded flexural bars were prepared from mixtures of 70 wt % of TOPAS 6017 with 30 wt % of each of the elastomers listed in Table 3. The bars were tested as in Example 1 and the results are summarized in Table 3. It will be seen that Topas 6017 is also impact toughened with Vistalon 8600, although the impact modification of this very high glass transition temperature (180° C.) material seems to be more difficult. This blend also has more than 500 J/m impact resistance. A slight change in the elastomer (Vistalon 7001) leads to a poorer result, although Topas 6015 and 6017 have the same Bicerano solubility parameter differences. Example 3 and Comparative Example 9 show that addition of higher levels of elastomers decreases the flexural modulus of the blends.
In these Examples blends of Topas 6015 and Topas 6017 were prepared with varying amounts of elastomer using a twin screw extruder to melt mix the blends. Test specimens were prepared using injection molding. The results are summarized in Tables 4 to 8 and
Comparative Example 10 in Table 4 shows the characterization data for neat Topas 6015. Without addition of an elastomer the room temperature notched Izod impact is only 22.9 J/m. These brittle polymers certainly could not be used in automotive applications. The heat distortion temperatures (HDTs) at 0.46 MPa and 1.80 MPa of Comparative Example 10 are 144.9° C. and 128.5° C., respectively. These high HDT's can be achieved because of the 160° C. glass transition temperature for Topas 6015. These heat distortion temperatures are much higher than can be achieved with blends of polypropylenes.
In Comparative Examples 11-13, 19-20, 24, 26, 28 and 30, Topas 6015 is blended with 20 wt. % of a wide variety of elastomers. The room temperature notched Izod resistance of these samples are plotted in
In
The styrenic block copolymers (Kratons and Septons) are all poorer than the Vistalons at improving the room temperature notched Izod impact resistance of Topas 6015. Note also that the ethylene plastomer, Exact 5061, (Comparative Example 24) and ethylene-propylene rubber, MDV91-9, (Comparative Example 19) are both significantly less effective at toughening Topas 6015 than the Vistalon 8600 and 7001 ethylene-propylene-ethylidene norbornene terpolymers. This result is unexpected based upon their similar compositions.
To explain the efficiency of the various elastomers, their Bicerano solubility parameters were determined and in
The toughening is so effective with Vistalon 8600 that no breaks are observed in the notched Izod impact tests at 23° C. for Comparative Examples 17 and 20. No other elastomer tested at a 20 wt. % loading had no breaks in the room temperature notched Izod impact test, which is a requirement for many automotive applications.
The injection molded samples have also been characterized by the Instrumented Impact test at several temperatures. In this test a projectile is fired at a disk of polymer at either 5 or 15 miles per hour. A ductile failure is required by several automotive manufacturers for some applications. The neat Topas 6015 in Comparative Example 10 is too brittle to even be tested. The blends containing Topas 6015 and 20 wt. % elastomer, Vistalon 8600 (Comparative Examples 17 and 20), Vistalon 7001 (Comparative Example 12), Kraton G1650/G1651 (Comparative Example 11), Kraton G1650 (Comparative Example 13), and MDV91-9 (Comparative Example 19) all show ductile failures at room temperature. However, only the Vistalon 8600 (Comparative Example 17) and Vistalon 7001 (Comparative Example 12) are also ductile at −29° C. These outstanding low temperature Instrumented Impact results are possible, because the ethylene-propylene-ethylidene norbornene polymers in Vistalon 8600 and 7001 have very low glass transition temperatures and are compatible with Topas 6015 and 6017.
It will be seen that the sample in Comparative Example 22 (Topas 6015 blended with 20 wt. % Vistalon 8600) exhibited more than just ductile failures in the Instrumented Impact test at −29 C unlike the 80:20 Topas 6015/Vistalon 8600 sample of Comparative Example 17. This difference is observed because the Instrumented Impact test in Comparative Example 22 used a 15 pound weight fired at 25 m.p.h. at the polymer disk. These testing conditions deliver more energy to the test specimen, making it harder to pass with ductile failure.
In Example 4 and Comparative Examples 14-17 and 20, a series of Topas 6015 blends with different amounts of Vistalon 8600 were prepared using the twin screw extruder and injection molding machine. In
Comparative Example 23 illustrates that it is not just the high loading of elastomer that is necessary to toughen Topas 6015. This Comparative Example used 30 wt. % of a high impact polypropylene to toughen the cyclic olefin copolymer. A poor room temperature notched Izod impact resistance of only 32.9 J/m was obtained. In order to achieve high impact modification, the elastomer needs also to be compatible (i.e., the difference in Bicerano solubility parameters needs to be between 0 and 0.6, preferably between 0.2 and 0.4 J0.5/cm1.5) with the Topas 6015.
Topas 6017 is an ethylene/norbornene copolymer with a glass transition temperature of 180° C. It is slightly more difficult to toughen than Topas 6015. See comparisons between blends of Topas 6015 and 6017 for 10 wt. % Vistalon 8600 (Comparative Examples 18 and 21 in Table 6), 20 wt. % Vistalon 8600 (Comparative Examples 20 and 22 in Table 6), and 30 wt. % Vistalon 8600 (Examples 4 and 5 in Table 7). At the same loading of Vistalon 8600, the Topas 6017 blends have slightly lower notched Izod impact values than the Topas 6015 blends. However, both cyclic olefin copolymers reach the target of 500 J/m notched Izod impact resistance when loaded with 30 wt. % Vistalon 8600.
The Topas 6017 blends have higher heat distortion temperatures at 0.46 MPa (for example 159 vs. 142.9 C for 20 wt. % Vistalon 8600) and 1.80 MPa (for example 138 vs. 121.3 for 20 wt. % Vistalon 8600) due to the higher glass transition temperature of the Topas 6017.
In
All documents described herein are incorporated by reference herein, including any priority documents and/or testing procedures to the extent they are not inconsistent with this text. As is apparent from the foregoing general description and the specific embodiments, while forms of the invention have been illustrated and described, various modifications can be made without departing from the spirit and scope of the invention. Accordingly, it is not intended that the invention be limited thereby.
This application claims priority to U.S. Provisional Patent Application No. 60/835,524, filed Aug. 4, 2006 and U.S. Provisional Patent Application No. 60/836,007, filed Aug. 7, 2006, the disclosures of which are incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 60835524 | Aug 2006 | US | |
| 60836007 | Aug 2006 | US |
