CA2187668A1 - Applications of isotactic polypropylene, processes and products thereof - Google Patents

Abstract

Applications of isotactic polypropylene resin compositions produced from metallocene catalyst are disclosed wherein the resins yield articles with comparable shear modulus and heat distortion temperature values to those of conventional polypropylene, but in which the fabrication of the article is achieved at temperatures much lower than possible for conventional polypropylene.

Description

21 87~6~
WO 95/30708 . ~
_ I _ APPLICATIONS OF ISOTACTIC POLYPROPYLENE.
PROCESSES AND PRODUCTS TFIF.RF.( \F
F~ELD OF TI~E lN V~;N I lVN
The present invention relates to ,. ' of " p~ u~
resin ~f~ More particularly, this invention relates to a process for forrning articles with stiffness and service t~ J~dtU._i. equivalent to those formed by . . ' processes using . ._..~U,.~I pul~ u~l~._ but which invention 10 process is operable at lower t.,...~..,.~u-~,...
BACKGROUND OF THE INVE~N TION
Isotactic yul.~lu~ , resins are useful for many ~. . " The relatively high end-use i . ~:, and high modulus of the material are two features which contribute strongly to its utility among polyolefins. Modulus refers to the shear modulus value of a given resin obtained through dynamic mechanical testing in accordance with ASTM D4065. For purposes of this invention, service 20 i . 1: is defined as the end-use: . ~i of the article, fiin~, sheet, or fiberproduced from the pc,l~,.u~ ,~ resin. The Heat Distortion Test ~DT), also referred to as Heat r r '- Test or Heat Deflection Test, is widely used to define the service i . ~; of i' . ' In this test, a weight is hung from a ' . _~ molded bar held in a chamber and the . I; of the chamber is 25 raised at a set rate until the bar droops a given arnount. This test is conducted in accordance with ASTM D648 at either 66 psi (455 kPa) or 264 psi (1820 kPa) specific load. The HDT value is a measure of the resistance to ,' ~( of a material under the influence of stress at an elevated i . ~;. HDT value is an indication of the highest i . ~; at which a plastic material retains acceptable 30 integrity for commercial utility. HDT values referenced herein are relative to the 66 psi (455 kPa) specific load test.
In order to maximize the utility of p~ ,.u~ , resirls, it is desirable to design the resin to have as high a modulus and HDT value as possible. TypicaUy, for ~ t;~.l.d pul~ylu~' resins maximizing the modulus and HDT value also 35 maximizes the melting point of the resin. For melt processing. such as done for injection molded articles, fabrication of the pul~,.ul"!~ occurs at i . _i,

2~ g7668 WO 95~30708 P~,l/u..:_.'~ 19 above the melting point The properties of p~ ,.u~,jlu.~ can be enhanced by orientation at i . ~,~ slightly below the crystaiiine meleing point Textiie fibers, uniaxiaUy, and biaxiaUy-oriented fiims are examples of products which benefit from such an orientation process For orientation processing, the 5 i . ~; of the pUI~Jlu~ is held at a t.~ ~ul~; slightly below the mdting point GeneraUy, in either processing, the high mdting point of the resin requires the use of high i . .,;, for the processing equipment. This is umdesirable because heating the resin to the elevated i . ~; prior to processing, and then cooling it down afterward takes additiorlai time which affects production rates and economics Additionaliy, this is undesirable because energy of the process suffers According to Spaleic, et.al., at a ~lu~ tal;ù.. made at the ~ "
Conference, Houston, Texas, May, 1993, the relationsilip between melting t; and room i . ~ modulus are different fûr ~ and 15 w~ ltiù~ i PC~ Spalek, etal, disclosed that " homo-PO ~ U~J;IU.~ have higher room i . ~ moduius vaiues than GU..~ tiù~i pGI~lJlu~ with comparable melt flow rate (MFR) and melting point (1~') vâiues~ In durable goods and high I r paci~aging .~ , one is mterested not oniy in room i . ~; moduius, but aiso in how this moduius 20 responds to devated It wouid be highiy desirable to i~lave a pGI~Jlu~ resin having high moduius and HDT vaiues, but which could be processed at a i . c below that required for a Cu..._.-tiul~i P~IJIU~YI~ with comparable modulus and HDT
vaiues. GeneraUy, this means having a resin with a high modulus and Hi~T vaiue, 25 but with a low melting pûint. For w... - ' isotactic l~ou~ullu~ of propylene, the crystaUine melting pomt is in the range of about 160-165C and the HDT vaiue is m the range of about 90-105C. For these w... ' isotactic . the orientation process generaliy occurs in a t~ lu~; range of about 135-155C Thus, orie~ation . _i, for w... ' pol~,,.u~,,!u..~, 30 are about 40-50C, or more, above the HDT vaiue It would be highiy desirable to process isotactic pGI~lutJJ~l~ resin at lower t~ than currently i~nown without . ,, ~DT value, modulus or other important properties of the resulting product WO9S130708 2 ~ 8 7 6 6 8 SIJMMARY OF TIIE INVENTION
We have found, ~u.~ , that isotactic pGl~u~!c.._ resins produced from " ~c~d catalyst systems have surprisingly low melting points when compared to a .,u.... ' POI~IUIJJI~I~ having similar modulus and service c (as measured by E~DT). The present invention relates to a process for forming oriented structures or articles, preferably oriented films, made from "- P~ JIU~JI~- at i . .,;. below cu...~ ' pul~ u~ c.._ resins.
0 In accordance with the present invention, there is provided a process for forming an oriented structure comprismg the steps of:
(a) forming a structure from a pu~".ul"~l.,.._ resin, said pul~l,.u~"' resm produced from a " catalyst;
(b) orienting the structure by applying stress at a t~ t~ c m the range from about 2ûoC above the HDT of the ~ul~ u~ c.._ to about 2CC less than the melting point of the pul~.u~.yl.,.._.
, the oriented structure may be processed, or oriented, at a C in the range of about 2ûoc to about 35OC above the HDT of the pol~ ~..u~" ' Preferably, processing occurs at a . c range of about 20OC
20 to about 3ûoc above the E~)T of the pul~.u~,,' A " - catalyst system is typicaliy employed for the production of the pUlJ~lU~ ,.._ polymer. The " - may be activated by a cocataiyst such as alumoxane, or an ionic compoumd capable of reacting with the " to form a catalyzed system.
25 The " may be employed in a I ~ form or ' ' ._1~, is supported on an inert carrier and optionally l,.cl,ul~ ' with olefinic monomer(s). In a preferred ~ l " t, the " is supported on a silica carrier.
~ u~ u~lc.._ produced from " catalysts is employed as either a 30 i . '3 or copolymer. Copolymers of propylene and a . having bet veen 2 and about 20 carbon atoms, and pol~t..ul.yl.,.._ blend c~ are aLo suitable for the process ofthis invention.
The oriented structures of the present invention may be films, fibers, thermo- or pressure-formed, or stretch molded articles. Conventional means may

3~ be employed to orient or melt-form articles from resins described in the present invention.

wo gs/30708 2 1 R 7 6 6 ~ P~ u.. '.'~
RRE~F DESCRIPTION OF TElE DRAWINGS
Figure 1 is a plot of the elastic modulus in shear versus L~.,~.,.aLIll~ for - "- isotactic p~ u~yl~ and w... ' pol~"u~ ,,,c.
DESCRIPTION OF TlIE I ~r r,r~;~ MBODIMENTS
T.~ . ~ ,.li ,. .1 ;""
It has been discovered that " catalysts produce isotactic pctl~t~lu~ resin, , having melting pomts lower than . ..t;Ul~l ~u~ lul~!u..., of similar modulus arld heat defiectiûn test values. Generally, these resins are propylene l ~ or propylene statistical copolymers that employ propylene and one or more ~ (s), preferably an alpha olefln havirlg from 2 5 to about 2û carbon atoms, or a cyclic olefn. The " produced pCtl~lJlu~ ,,~ may also be a blend of IJ tl~ U~J"~ a~d another polyrner with different properties.
The present invention relates to .,' of these pU!~
made from " catalysts, arld processes for orienting 20 structules from these rcsins. Orienting structures are generaUy defned as films, sheets, fibers, or molded articles as described herein. The orienting or moldingprocesses occur at i . ' .,i. Iower than that currently available for w ~. - ' p~)l~",ll r~' resins. For purposes of ~his invention, C~.. t u~dl POI~ IU~)JI~ iS that polymer produced from Ziegler-Natta catalysts; "~
PO~ IU~JI~.~ iS that polymer produced from single-site, or ~y~
derivative trar~sition metal catalysts. r~ u~ , refers to isotactic PO~ U~ , homo- or copolymers or blends thereof. Copolymers refers to propylene based polymer prepared from propylene and one or more other monomers.
The principles embodied in the present mvention are appGcable to most processes where reduced i . c; orientatio4 or forming, is a value. In melt t processing operations, tbe ~ of the melted polymer just prior to forming the article is largely determined by two factors. First, the ~ ~aLL~lc; must be sufficiently above the melting point of the polymer to guarantee the ' -of the molecules. Second, the . ~; must be high enough so that the fiuidity of the melt is sufficient to aUow the melt to be injected into the mold or otherwise wo s~/30708 ~ ~ 8 7 6 6 ~; r~ 5.s~
formed into the desired shape. Wlth the , _', low melting points of the materials of the present invention, the first limitation on melt i . c can be relieved. This can lead to lower energy ~ , and faster processing speeds for the equipment. Almost any i' . ' fabrication process can benefit from 5 these findings. Examples of processes other than those for oriented film and fibers where reduced i . ci orientation may be of value include D~
molding, stretch- ~~ '' _. solid phase pressure forming or any ~ _ operation where the forming takes place at a iic~ .a~ul~z below the melting point of the material. Examples of melt forming processes which may alsoo benefit from reduced i, CD include profile extrusion, sheet extrusion (optionaUy followed by ' r ~ ' extliusion~
nonwovens extrusion, and the like. As an example, currently, r _ operations of - ' ~ rJ ~ occur at a i . _ of about 155-160C. Wlth the " of the present invention, ' '` _ 15operations may occur at a i 1, ~i range of about 140-145C.
Examples of uses for the oriented film products made in accordance with the present invention include oriented film products for snack packaging or other food wrap, film products for heat sterilization or cook-in bag uses. Examples ofuses of melt-blown articles formed in accordance with the present invention include ' ' ' rigid packagmg, injection molded parts for major appliances and automotive interiors and exteriors.
1~,' " UC~fi~l in Preferred ~ ' ' In the most preferred ' ' t, the pc.l~".u~ ,h..c employed is produced from at least one " comprising bridged, b;D~r Jl~
Groups 4, 5, or 6 transition metal, dihalide or dialkyl derivatives. Even more preferred " include bridged bisindenyl, Group 4 dihalide derivatives.
Specific " catalysts known to be usefiJI for producing isotactic p~t~,.ul"' are discussed in EPA Nos. 485,820; 485,821; 485,822; 485,823;
518,092; and 519,237; US Pat Nos 5,145,819; 5,296,434, aU herein by reference for US patent practice purposes The preferred "~ employed in accordance with this invention are chiral and used as a racemate for the preparation of isotactic poly-l-olefins.
IUustrative but non-limiting examples of " mclude~ b;;~(2-~' ' ,') zirconium dichloride, :' 'J's~ J(2-ethyl q l' ,' ' yl) zirconium dichloride, ~' ' ,' ',~lb; .(2-methyl-4-~JI....~' ' Jl) zirconium woss/3070s ~1 87668 r~ C~

dichloride, ~ ' '',yl' ;..(2-methyl-5-iD~Jvu~ ) zirconium dichloride, !" " ,' ''yll-;~(2-methyl-4,5-benzindenyl) zirconium dichloride, and, !'' '' ,' ''ylb';~(2-methyl-4,6-d~ " ' jl) zirconium dichloride. The most preferred specific " is ~" h;''l~ (2-methyl-4,5-benzindenyl) zirconium dichloride. Although silyl bridge and zirconium transition metal is specificaDy disclosed, one of skili m the art would appreciate that other types of bridging systems amd transition metals may be employed.
The " - employed is preferrably supported on an inert carrier and optionally ~ ' ' Numerous support techniques are known in the art.
Most preferred is the techr~ique employed in accordance with US Pat. 5,240,894, herein i,.~,~,lr ' by reference. Preferably, the supported "- is omployed in a ~ ' ' fashion. The prepolymer may be any alpha olefm, preferably ethylene, propylene, or butene, most preferably ethylene ~
The " is preferably employed in the form of a complox of the " with am activator. Activators may be alumoxane, as is well known m the art, or ionic activators such as disclosed in U. S. Pat. 5,198,401 or 5,278,119.
It is beiieved that any compoumd which serves to activate the " to a cataiytic state is appiicable to this invention.
r~ "luv~L,~,~,ofthPPr~ nVPntinn The p~ ".. . ,' employed in the present invention r^ay be a r ~ or copolymer or blend of propylene produced by gas phase, slurry, bulk, solution or high pressure ~ ' ' processes using a catalyst. Preferably, the polymer is a i . '~ of propylene which has a lower melting point than pGI~,.u~' produced from c~,.... ' ' cataiysts having simiiar modulus and heat de'dection ~( . i. The polymers may be produced m 'duidized or stirred bed gas phase reactors, slurry or bulk reactors of tank or loop type or any other process practiced for the p~ ' ' of propylene.
Preferably, a supported catalyst system ( " plus some activator 30 ; . t) is employed m a siurrv or gas phase reactor to produce the propylene polymer.
Copolymers mclude propylene amd at least one (or aipha olefin), wherem the has between 2 and about 20 carbon atoms. The polymers are prepared by ~.... ' ' means using a " cataiyst.
35 Exemplary ~. include ethylene, butene-l, hexene-l, and 4-methyl-1-pentene. Propylene copolymers employed preferably have a content m 2~ 87~68 wo ss/3070s r~ u the range of about 0.5 to about 10 weight percen~. Other polymer mixtureS or blends having 3 or more polymers may be employed. Exemplary blends rnclude PUI~ U~ with a p~ ll.,!.".." butene-l copolymer, snd an Other ingredients can also be included in the polymer ,: . These can be selected from additives commonly employed with plastics, such as fillers and/or l~ , fibers, plasticizers, colorants, dyes, fiame retardants, . ' pigrnents, mold release agerlts, drip retardarlts and the Gke,in ~u.... ' amourlts. Effective amounts are selected normally ranging from o about 0.1 to about 1 00 parts per hundred by weight of the polymer.
The p~ u~h,.~ resins suitable for use rn the present invention, and which have been found to rmpart the unexpected and superior properties are thosewhich have a modulus and HDT value comparable to Cull._.lLiul~l pOI~ u~/G,ll.,, but which carl be processed (as evidenced by therr HDT value) at lower 5 i . ~,.,. These polymers generally have narrow molecular weight distribution (MWD = MwlMn = about 1-5, preferably 1-3, most preferably about 1-2.5). They also generally have narrow ~ ;.. - distribution and tacticity Aictrih ltinn The copolymers will generaDy exhibit meltrng points rn the range of from about 100Cto about 145C, more preferably rn the range of about 1103C to about 135C, and most preferably in the range of from about 120rC to about 135C. Hc.lllopc.l~
typically exhibit melting pornts about 140C to about 160C. Films prepared in accordance with the present rnvention will typically exhibit low n-hexane , generally less than 10 wt % and preferably less than about 4 v~t%, and are therefore desirable for products used in food and medical 1, r Useful melt fiow rates (MFR), as measured by ASTM D-1238, of the polymers ofthe present invention are rn the range of from about 0.1 to about 5000.
In a preferred ' ~ " ~ the melt fiow rates range from about û.5 to about 200.
Preferred MF~ ranges for film and moldrng ~ are from about I to about 10, with most preferred being from about I to about 5. Oriented fibers produced by fibrillation or sGtting of oriented film preferably have MFR ranges of about I to abouat 10, and most preferably a range of about I to about 5. Fibers produced byw.... ' spinring processes preferably have MFR of about 10 to about 200, most preferably from about 30 to about 125.

WO95/30708 21 &7668 ~ I~"~

Fi~ n~l St Films may be produced by techniques known to those of skill in the art.
For example, blown films produced with an annular die and air cooCng, or cast films using a slot dCe and a chill roll for cooling are acceptable techniques. Films are generally m the range of about 0.2 to about 10 mils (5 to 254 microns), however, total thickness may va~y based upon the desired appCcation. Sheets may be prepared by CUA~ techniques such as extruding a ' "~ fiat profile from a die. Sheets win generally have a thickness of from about 10 to about 75 mils (254 - 1905 microns), although they may be ' "~ thicker.
0 Films or sheets produced within the scope of the present inventio4 may be oriented at lower i, ~.,. than currently known with . .lt;ullal p~ u~k.,~,. Oriented films may be whieved by either post extruder . ' ofthe blown film through heating and orientation, or by post extruder tentering techniques. Depending on the extent of stretching desired, either a film or a sheet may be the precursor for the oriented film products described herein.As an orienting film example, at the present time, Cu..._.ll.iu~
~ol~.u~ having an HDT value of about 95C, and a melting point of about 160C is generally oriented at i . _,. of about or greater than 135C in the mwhine direction ~MD), and 155C in the transverse direcLon CID). Use of the " produoed resins m accordance with this invention having ' ".~
similar serYioe . c; and modulus aUows orientation to occur at about 125C and 140C for the MD and TD .~.~L._I~ .
The oriented films of the present invention may be in either single-or multi-layer (composite) form. Composites would include at least a first skin layer and at least one other layer. They may be formed by (I) coextrusion followed by orientatio4 (2) orientation of a film followed by laminatio4 or (3) orientation of a film followed by extrusion coating. Lower orientation ~ ; has advantages m coextruded films wherem the skin layer is produced from a polymer which melts at a lower i . ~; than the " p~ ,.,c comprising the other layer. First, the lower melting " I )~ '~ layer allows one to use very low l '; . e skin resin without the cavity sticking problem often ed on MD orientation of films. Further, loss of optical properties in fihns of this type is attributable to the melting of the very low melting seal layer resirl at the processing . _. In the present mvention, the processing i . _ is .~ , lower, thus minimizing seal layer melting and preserYing the good optics of the film.

W095f'0708 2 i 87668 r~l" - ~
g Oriented films or products therefrom produced from " - c2talysts 2re expected to possess moisture (or w2ter) vapor i r2te (MVTR) properties similar to products formed from resins of Wll._ ' ' c2talysts.
Moisture v2por r2tes 2re indicators of the film's 2bility to serve 2s a 5 barrier for water or moisture. Wlth the current processes for forming films from w.... ' resins, the MVTR wiO deterior2te 2s the melting point of the resin is decreased. Wth the present inventio4 the lower melting pomt of the resin, 2nd reduced processing . c is achieved vithout C~nll~ G the moisture vapor barrier properties of the final film.

Flbers may be formed employing molten polymer in ~l..~.lt;olldl methods such 2s traditional melt-spinning, oriented sheet slitting, and oriented film fibrillation. The fibers m2y be DubDc~ .~ly employed in woven or non-woven 5 f2brics. Passing the fibers or precursor film over sequential heated roOs oper2ting 2t different speeds effects the needed orient2tior~ Wlth the process of the present inventio4 these roOs can be operated at ' "~ lower: , ~D than current commercial practice.
20 Mnl~l Artirl~c Molded articles may be fabricated by .. ' techniques such as, '; '" g, '; 1:' .. molding, extrusion-blow molding, rotational molding, or foam molding. Molded parts are found in many ' ' , generaOy about 500 microns (20 mils) or greater. It is import~mt that the resin be heated25 ~ above the meltirlg point to randomize the molecules. Resirl~D of the present invention aOow lower '~--T ' .D for this heating process than w...~ ' resins FrP~t DPflPI tinn Test . r r ~ ~ ~ TPct ~ F~re 1:
As discussed previously, heat defiection t~ . is an indication of the re istance to !' " '' of a material under stress at an elevated ~ , .
The: , e at which a material deforms to a prescribed extent is the heat defiection ~, c (or heat .' r " ' , ' C) and is important to r ' 'CID for ' g processing parameters of the resin and service 35 , c of the re ultant article.

21 87~68 WO 9~/30708 r~

Dynamic mechanical tests measure the response of a plastic material to perio&c or varying ~ GeneraOy, the applied ~l f~ " varies sinusoidaOy with time, and the resultant force required to deform the sample likewise is sinusoidal. Dynamic testing allows one to readily measure modulus ofs dasticity and damping or viscous properties of a polymer as a function of c and time.
Figure I is a dynamic mechanical plot of the elastic modulus in shear versus t~ Lu~e for .. ' and I " isotactic ~ ,.u~,.~l~,..~,.
GeneraDy, one of skiD in the art might expect that even though the material has a 10 high room i . ~; modulus, a low melting "- pcl~,.u~ ,., would have a low HDT value. Conversely, a high melting point material could be expected to have a high HDT value. Figure I &spels this notion.
The " ~ ylu~ un~, of Figure I has a melting point of about 145C while the . ._...iUI~ 'IJIUI~J' has a melting point of 5 about 1620C. In Iine with earher reports, the modulus at 300C is somewhat higher for the ' " pGl~)lù}JJL,..~,. T~ ., the moduli at 100C (typical heat ~ ; for w.... ' pu:~".u~ ) are seen to be the same for the two polyrners. At 130C the two polymers have &fferent moduli. Further the '- resin actuaDy had a higher HDT value 20 than the w.... ' polymer. The traditional or w .. ' view of this result leads one to expect higher modulus and service t~ Lule PUIYIJIU~IU.~ resms as " catalyst technology matures and melting points approach the 160C
level.
For estimating processing orientation i . ~; of polymers, the data of 25 Figure I are useful. We can determine from Figure I that a modulus of a~ 2 x lo8 dyn/crn2 is required for efticient stretching. The ' ~ PUI~/IU~ IU~A~ reached this needed modulus level at about 135C while the w... ' P~)4~ reached this modulus level at about 150C. The present invention takes advantage of these attributes of the " resin to 30 defne a process operable at lower i . ~,., than currently possible with today's w..._..~iu.~ resins, but which yidd a product ' q~ equivalent to today's best film products.
r-- Oriented Structures:
~ accordance with the preferr.ed; ~ of this invention, there is provided a process for forming an oriented structure comprising the steps of:
.

,~ w0 9sl30708 2 1 8 7 6 6 8 P~ S~

(a) forming a structure from a p~ u~ resul, said pol~.u~,!.,..
resin produced from at least one " - cataiyst; and, (b) orienting the structure by applying stress at a t---T ~i in the range of from about 2ûoC to about 35GC above the E~T of the pGI~,plu~J~ . A
5 more preferred orientation , ~ range is fiom about 2ûoC to about 30OC, and most preferred range is from about 250C to about 3ûoC abûve the HDT of the pu)~u~flu..~,. Aiternatively, one may consider upper orientin~
ranges to be about 35OC, 30~C, and 25OC above tile HDT vaiue of the pc,l~l,-u~ ,.~ and lower orienting h r ' _D to be about 200C and 250C above tile ~T vaiue of tile l.u~ ". u~" ' An aiterrlate ' ' reiates to a process for forming an oriented composite fiim wherem a fiim or sheet comprising (a) at least one first layer of a pul.~ upflu,.., poiymer produced from a " cataiyst, and, (b) at least one other layer of sûme polymer having a lower melting point than tile first layer of (a) is stretched, or oriented, by applying stress at a t~ in tile range of from about 20OC to about 35C above the HDT vaiue of tile " cataiyzed pc,l~,.u~"~u.~. Preferably the " pc,~,.u~"' in a composite film is a ~ , but tilis is not necessary, and depends on the desired ~ - ' of the finai fiim.
A further . b~ ' of the present invention reiates to the maximum ~,. y" ,,.t.,," to be applied during orientation wherem the rnaximum . ~;
does not exceed about 35C above the E~T ofthe pc,l~,.u~"' EXAMPLES
The foiiowing iiiustrative, but non-limiting examples wili further iiiustrate the ir~vention. They are not to be construed tû hmit the claims in any manner.
Synthesis of the " employed for production of the isotactic pc,4t..u~"~,., ilUlllUlJUII~, of the example is a multistep process as outiined below.
SVnthPcicofr/~ ivlhic~ A ~ ' nvl)-~iPth~yl I ~th,yl (~ thyl) ~ ' (11 5.15 g (224 mmol) of sodium were dissolved in 150 mY of absolute ethanoi, 35 whiie heatmg, and 37.3 mi (217 mmol) of diethyl I~ Ll~ ' were added at room . A solution of 50 g (217 mmol) of 2-i~l~ ~' . ' ' ' WO 95/30708 2 1 8 7 6 6 8 r~ ,s ~l9~ ~

(g6% pure) in 270 ml of ethanol was slowly added dropwise at 0C, and the mixture was heated under refiux for a further 4 to 5 hours. It was poured onto ice-water and extrsoted with ethyl acetate. The combined organic phases were dried with sodium suhfate and evaporated. After drying under an oil pump vacuum, the s oily residue was stirred with hexane at 0C, whereupon 55 g (81%) of the compound 1.,.~ " ' Syllth~eic of 2 ~ ' ~.h ' ~ , acid (2) A solution of 23.7 g (422 mmol) of potassium hydroxide in 50 ml of water o was added to 33.2 g (105 Inmol) of the compound I in 70 ml of ethanol, and the miAture was heated under re'dux for 4 hours. After the solvent had been strippedof i; the solid residue was taken up in ethyl acetate, water was added amd the pH
was brought to I with h~ ' ' ' acid. The aqueous phase was eAtracted several times with ethyl acetate. After drying over magnesium sulfate, the combined organic phases were evaporated completely. The residue was stirred with hexane for .,.~ " For d~l,~.Ayl,.,iou, the beige-colored solid was heated at 175C umtil the evolution of gas had ended. 21 g (g4/0) of the product 2 were obtsined as a beige-colored solid.
Synth~cic of 2 ~ 7-' 1- ~3) 22 ml of thionyl chloride were added to 21 g (98 mmol) of the compoumd 2, with exclusion of moisture, and the miAture was heated urlder refiux for 30 minutes. Excess thionyl chloride was then distilled off. The residue was briefiyfreed from volatile compounds under an oil pump vacuum and then dissolved in 25 ml of methylene chloride, under Ar as an insert gas. The solutiorl was slowly added dropwise to a suspension of 26 g (196 mmol) of aluminum trichloride in 60 ml of methylene chloride and the mixture was heated under refiux for a further 30 minutes. It was poured onto ice and eAtracted with methylene chloride. The combined organic phases were dried with sodium sulfate and evaporated. The dsrk oily residue was .,lm ,, .' ' on 600 g of silica gel 60. 8.6 g (45%) of the compoumd 3 were able to be eluted (yellowish solid) with a mobile phase mixture of I 'e ' yl acetate (9:3).
Sy~th~cic of 2-1U~t~yl-4 5-~ ' (4) 2.2 g (59.5 mmol) of sodium b~ ,hJ.l.ide were added in portions to a solution of 7.8 g (39.7 mrnol) of the indanone, compound 3 in 400 ml of a 2 1 ~7~8 wo ss/307os P~l/u . .

t~t. ~" -, r / ' ' mixture (2:1) at room t~ C~rLul~ and the mixture was stirred for 14 hours. The solution was poured onto HCL-acid ice and extracted with ether. The combined organic phases were washed several times with water and dried with sodium sulfate. The orange-colored oil which remained after the 5 solvent had been stripped off was dissolved in 240 ml of toluene, snd the solution was heated at 80C with 570 mg (3.15 mmol) of p-toluene-sulfonic acid for 15 minutes. It was washed several times with water a~ room , c, dried with sodium sulfate and evaporated. The residue was ~,Iu~ ,, .' ' on 300 g of silica gel 60. 4.7 g (65%) of the indene 4 were able to be eluted (colorless oil) with a mobile phase mixture of L ~ ether (20:1).
IH-NMR spectrum (360 MHz, CDCL3): 8.02 (I,d), 7.84 (I,m), 7.59 (I,d), 7.52 (I,d), 7.38-7.48 (2,m), 7.06 (I,m), 3.42 (2,s), 2.25 (3,d).
10.2 ml (25.5 mmol) of a 2.5 M ' ~, " ' solution in hexane were added to a solution of 4.6 g (25.5 mmol) of the compound 4 in 50 ml of ' /.1.. '`
at room; . c, and the mixture was heated under reflux for I hour. The red solution was then added dropwise to a solution of 1.55 g (12 mmol) of :" ' .t' ' ' ' . ' m 10 ml of ., . ~ r at room ~ . t;, and the mixture was heated under reflux for 5 to 6 hours. The reaction solution was poured onto ice-water and extracted several times with ether. The cornbined orgsmc phases were dried with sodium sulfste and ~ -r 1~ and the residue was dried under an oil pump vacuum. It was ~Iu~ ,, . ' ' on 300g of silica gel 60.
500 mg of um-eacted starting compound 4 were initially able to be eluted with a mobile phase mixture of hexane/3% ethyl acetate. The hgand system, compound 5, then followed with the same mobile phsse. After the solvent had been stripped of i, this hgand system was crystalli_ed (isomers) from hexane. The yield was 1.7 g (34%, or 44% with respect to the indene, compound 4 reacted).
~ ~f pr - Dim ~ (2 ~1 A S-h~7~ Z
tlirhlr ritl~o (6)

4.0 nl (10.2 mmol) of a 2.5 M l,ul~" ' solution in hexane were added to a solution of 1.7 g (4.1 mmol) of compound 5 i~ 20 ml of i ' ,.~ '` at room . .; under Ar as an inert gas, and the mixture was stirred at room ~ for 14 hours. The residue which remained after the solvent had been stripped off was dried using an oil pump vacuum and washed with hexane. The 3~ psle brown powder obtained was dried using an oil pump vacuum at 40 to 50Cfor several hours and added to a suspension of 1.0 g (4.0 mmol) of zirconium . . .

WO95B0708 2 1 8 766~ r~.,~

..; l in 25 ml of methylene chloride at -7gC. After the mixture had been warmed to room ~ the solvent was stripped off and the residue was extracted with 20 ml of toluene in order to remove the meso form of the " ~, compoumd 6. The residue of the toluene extract was then extracted

5 with 40 ml of methylene chloride. The solution was ~ ' to a smaO
volume and lef~ to clystaOize at -35C. A total of 970 mg (42%) of the .o~..~., compound 6 were isolated in several fractions as the pure racemate.
IH-NMR spect um of the racemate (300 MHz, CDCL3): 7.96 (2,m), 7.78 (2,m), 7.60 (2,d), 7.48-7.56 (4,m), 1.36 (2,d), 7.27 (2,s,b-Ind-H), 2.37 (6,s,Ind-CH3),1.36 (6,s,Si-CH3). Mass spectrum: 574 M+, correct ' ,, correct isotope pattern.
nrti~ (~at~lyst (~ - (6) To an eight-Gter vessel equipped with a cooGmg jacket and an efficient overhead stirrer was added ' ~' ' (30 wt% m toluene, 925 rnl). W-lth stirring, a suspension of compound 6 (5.0 g) in toluene (700 ml) was added underN2 through a d~uhlu-~Jcd needle. After sti~ring for 10 minutes, dehydrated siGca(Davison 948, dried at gOOC, 200 g) was added to the solution over 20 minutes.
The slurry was stirred for 10 minutes and then, while a vacuum was appGed from the top of the vessel, a sGght f~ow of N2 was added through the bottom . The mixture was heated to 70C as the solvene was evaporated over a 9 hour period.
The dry soGd was cooled to ambient i , ~ overnight. Isopentane (5 liters) was added to slurry the soGds and the mixture cooled to 0C. Ethylene was added to the stirred mixture by a dip tube at a rate of 0.03-0.06 SCF/minute until a total of 491 Gters of ethylene had been added. Agitation was stopped and the solids aOowed to settle. The Gquid was decanted from the soGds, w_ich were washed twice, each with 1.5 Gters of isopentane. The wet soGds were transferred to a dry-box urlder N2 and filtered through a #14 mesh sieve. The flne particles were filtered off, washed with pentane (4 Gters) and dried in vacuo. Yleld: 326g.
r with Su~portedCom~ound 6 T o~ee Scale Production of Polymer:
The l r ~'~ referred m Figure I was produced in a continuous, single reactor, bulk Gquid phase pc,l.~ process. The reactor was equipped with an agitator, and jacket for removing the heat of reaction. The reactor , . was set at 65C, and supported ~ ' catalyst (compound 6) ~ w095/30708 2 ~ 8 766~ r~

was fed to the reactor at a rate of 1.3 g ~ ~..t,q.~,ul. Propylene was fed to the reactor at a rate of 60 kg y. uyJlu~l~ qluul . A continuous flow of hydrogen (0.75 g h.~d~u~ qluu~) was used to control the molecular weight of the product. The average residence time of the catalyst in the reactor was 4.0 hours and polymer 5 was produced at a rate of 9.1 kg pGI~ Ihu,.,. The product had a 7 MFE~
(230C/2.161cgperASTMD1238),andapeakmeltingpointofabout 145C.
The l . '.; resm obtained above was miYed with O.û5 wt% Irganox 1076 for oxidative stability and pelletized on a one mch diameter lab extruder at conditions typical for pol~luy~- The samples were prepared for testing m o accordance with ASTM D4101. The injection molding was done on a Van Dorn 75 ton molding press. Standard yvl~yluyJ' - conditions were used in the molding operation.
('. FY~71"
Conventional pol~yluy~ PP-1024, obtained from ExYon Chemical Company, Baytown, Texas, was chosen as a comparison standard to the above described " - prepared yc,l~yluy~ sample. PP-1024 had a 12 MFR
and a MP of about 162C. The sample was prepared for testing in accordance with ASTM D4101. The injection molding was done on a Varl Dorn 75 ton moldmg 20 press. Standard y~l~yluy~ conditions were used in the molding operation.
' PrPr ~tin~ ft~rTT~f ~:~f~r~fir~n ~ ~r . 1`'- . ~ T~ j~
Samples for both heat distortion and dynamic mechanical testing are prepared m the same manner. For pGl~uy~ c~ the samples are melted and 25 injection molded according to ASTM D4101 Sample dimensions for the heat distortion test are 6" x 0.5" x 0.125"; for dynamic mechanical testing, sample dimensions are 2" x 0.5" x 0.125n. A common practice is to cut the heat distortion sample to a 2~ length for dynamic testu~g.
30 r ~ T ' ~t ~1- ' '- TPCt The samples described above were subjected to a Heat Distortion Test (HDT) conducted in accordance ~vith ASTM D648 at 66 psi (455 kPa) specific load. The heat distortion for the "-~ PO~ UY~ sample was found to be about 101C; am HDT value of about 93C was found for PP-35 1024.

21 876~8 WO 95/30708 1~ r ~ r , Dynamic mechanical testing was conducted by oscillating a solid rectangular beam, fixed at one end, through an arbitrary angle of de'dection. The force required to deflect the sample is measured. The force and angle of deflection are used to calculate stress and strain ~ . The ratio of the stress to strain 5 yields a modulus. Varying the i , ~ during the test yields information about the behavior of the material as a function of i . ~;. Results of the dynamical mechanical testing for the "~ pol~..u~.,' and the Wlll~ a~iV~ sample PP lû24 are illustrated in Figure 1. Rc~ ta~;~_ illustrative data are also in the table below:

Table: Illustrative Data of Moduli versus Temperature for Met PP~ and PP 1024.
Modulus (dyn/cm2) Ti . c (C) T: , c (C) r~ Pp PP 1024 2 x 107 150 170 I X lo8 147 165 2 x 1o8 135 150 4 x lo8 125 135 8 X lo8 lOû 100 5 The data found m the table are ay~JI, ' values.
~ = r~ - r~
Those sl~lled in the art will appreciate that ~ r " and variations of the present invention are possible in light of the above teachings without departing 20 from the scope or spirit of the present invention It is, theref~re, to be understood that changes may be made in the particular i ~ ' of the mvention described ~vldd~ efi~d=t~d~d~ppp~of~e~ppepdedcll~ims

Claims (11)

CLAIMS:

1. A process for forming an oriented structure comprising the steps of:
(a) forming a structure from isotactic polypropylene resin, said polypropylene resin produced from a metallocene catalyst and, (b) orienting the structure by applying stress at a temperature in the range of from 20°C to 35°C above the HDT value of the polypropylene;
wherein at no point during the process is the structure heated to more than 35°C
above the HDT value of the polypropylene.

2. The process of claim 1 wherein the temperature range is from 20°C to30°C, preferably from 25°C to 30°C above the HDT of the polypropylene.

3. The process of claim 1 or 2 wherein the polypropylene is a homopolymer.

4. The process of any of the preceeding claims wherein the polypropylene is a copolymer of propylene and at least one comonomer having between 2 and 20 carbon atoms, preferably ethylene, butene or hexene.

5. The process of claim 4 wherein the propylene copolymer has a comonomer content in the range of 0.5 to 10 weight percent.

6. The process of any of the preceeding claims wherein the polypropylene is a blend of polypropylene and another polymer.

7. The process of any of the preceeding claims wherein the metallocene comprises a silicon- bridged bis(substituted indenyl) Group 4, 5, or 6 transition metal dihalide.

8. The process of claim 7 wherein the metallocene is selected from the group of dimethylsilylbis(2-methlindenyl) zirconium dichloride, dimethylsilylbis(2-methyl-4,5-benzindenyl) zirconium dichloride, dimethysilylbis(2-methyl-4,6-diisopropylindenyl) zirconium dichloride, dimethylsilylbis(2-methyl-4-phenylindenyl) zirconium dichloride, preferably.

9. The process of any of the preceeding claims wherein the metallocene is supported on a carrier.

10. The process of claim 1 wherein the oriented structure is a fiber.

11. The process of claim 1 wherein the oriented structure is a molded article.