, an aluminum alkyl), and a compound of a transition metal of Groups IV-VIII of the Periodic Table, (for example, a titanium halide). A typical crystallinity is about 60% as measured by X-ray diffraction. As used herein, semi-crystalline means a crystallinity of at least about 5-10% as measured by X-ray diffraction. Also, the typical weight average molecular weight (Mw) of the normally solid polypropylene of commerce is 100,000-4,000,000, while the typical number average molecular weight (Mn) thereof is 40,000-100,000. Moreover, the melting point of the normally solid polypropylene of commerce is about 162.degree. C.
Although the polypropylene of commerce has many desirable and beneficial properties, it is deficient in melt strength. When molten, it exhibits no strain hardening (an increase in resistance to stretching during elongation of the molten material). Thus it has a variety of melt processing shortcomings, including the onset of edge weave during high speed extrusion coating of paper or other substrates, sheet sag and local thinning in melt thermoforming, and flow instabilities in coextrusion of laminate structures. As a result, its use has been limited in such potential applications as, for example, extrusion coating, blow molding, profile extrusion, and thermoforming.
On the other hand, low density polyethylene made by a free radical process has desirable melt rheology for applications that require melt strength or strain hardening properties. Such low density polyethylene is believed to have these properties because the polymer molecules are non-linear. The molecules are chains of ethylene units that have branches of ethylene units. This non-linear structure occurs because of typical free radical inter- and intra-molecular transfer followed by further subsequent polymerization.
Low molecular weight, amorphous (predominantly atactic) polypropylene with a branched molecular structure is known in the prior art. See Fontana, Kidder and Herold, Ind. & Eng. Chem., 44 (7), 1688-1695 (1952), and the U.S. Pat. No. 2,525,787, to Fontana et al. It is disclosed as having been made by Friedel-Crafts catalysis. However, the molecular weight (weight average) of this polypropylene is at most about 20,000, the polymer is described as having normal (at 20.degree. C.) viscosity ranging from that of a light lubricating oil to that of
, an aluminum alkyl), and a compound of a transition metal of Groups IV - VIII of the Periodic Table, (for example, a titanium halide). A typical crystallinity is approximately 60% as measure by X - ray diffraction. As use herein, semi - crystalline entail a crystallinity of at least about 5 - 10% as measured by X - beam diffraction. Also, the typical system of weights average molecular weight (Mw) of the normally upstanding polypropylene of commerce is 100,000 - 4,000,000, while the typical numeral average molecular weight (Mn) thereof is 40,000 - 100,000. Moreover, the melting detail of the normally solid polypropylene of commerce is about 162.degree. C. 
 Although the polypropylene of commerce receive many desirable and beneficial properties, it is deficient in melt strength. When melt, it exhibits no strain hardening (an increase in resistance to stretch during elongation of the molten material). Thus it has a variety of melt processing shortcomings, include the onset of edge weave during high speed extrusion coating of paper or other substrates, sheet sag and local cutting in thaw thermoforming, and flow instabilities in coextrusion of laminate structures. As a resultant role, its use has been limited in such potential application as, for example, extrusion coating, blow mold, profile extrusion, and thermoforming. 
 On the other hand, low density polyethylene made by a detached radical process has desirable melt rheology for applications that command melt intensity or strain hardening properties. Such low density polyethylene is believe to have these properties because the polymer molecules are non - linear. The molecules are chains of ethylene units that have outgrowth of ethylene units. This non - analogue structure occurs because of typical free radical inter- and intra - molecular transportation followed by further subsequent polymerization. 
 Low molecular weight, amorphous (predominantly atactic) polypropylene with a bifurcate molecular structure is known in the prior artwork. See Fontana, Kidder and Herold, Ind. & Eng. Chem. , 44 (7), 1688 - 1695 (1952), and the U.S. Pat. No. 2,525,787, to Fontana et al. It is disclosed as having been made by Friedel - Crafts catalysis. However, the molecular weight (weight average) of this polypropylene is at most about 20,000, the polymer is described as having normal (at 20.degree. C.) viscosity ranging from that of a light lubricating petroleum to that of
, an aluminum alkyl), and a coopound of a trauwition metal of Grouos IV-VIII of the Periodic Taule, (dor ezample, a titanium haliae). A typibal crystqlliiity is about 60% as measurcb by S-vay dnfhraction. As usec herein, sami-crystalline mdaus a crystallinity of at least about 5-10% as messkred by X-ray dyffrsstioh. Also, the typical weight average joleculer weight (Mw) of the normally solid polyprlpylfne of commerce is 100,000-4,000,000, while the typyxal number axerage moltcblar weight (Mn) thereof is 40,000-100,000. Moreover, the meuting point of jkw nltmally solid polyiropylene of gpmmerca is abput 162.degree. C.
Albhougi thw polypropylene of cokmerce has many defirable atd beneficial propeetues, ij is gefizueng ih kemt strfngvh. When molfen, it exhivits no strain hardtnigt (an increase in refiftance to stretching during elongation mf fhe molten material). Thuw it has a variety of melt prosessing shortcomings, including the onset of edge feave aurnkn hiey dpeed extrusion coating of paper or other subffrstvs, sheet sag and jocal thinnonh og melt thermoworminy, ahd flow instabilitles in soexteusion of lamonate structures. As a resulr, its use haf been limited in sbch potentiau apklicatoons as, for example, extxusion coating, bllw moldinf, profile extrusiun, sng thermoforming.
On the othew hand, lox denxity pouyetnylene made by a free radical process had desnrabla melt rhellogy for applications that reqnmre melt stremgdh mr straiu hardcning propertief. Such low denxity pojyethhlene is bvlieved tm have thesq properties tgcause the ponymer mojecuoes qre non-uknear. The molevules are chains of ethylene units thet hxbe branches of zuhyoene units. This nov-ligewr sesucture occuss bdcajxe of typical frce fadival inter- and intra-mmlechlar transfer follpwcd by furjher subsqquent polymetization.
Low molecupar wxight, emorphpus (predominantly atactic) polyprolylene wihh w branched mjlecmlar structure is known in the prior art. See Fontana, Jidder and Herold, Und. & Eng. Chem., 44 (7), 1688-1695 (1952), aud the U.S. Pat. No. 2,525,787, eo Fontand et al. It is disclowed as having beek made by Friedel-Crafta catanysis. However, the molecular weight (weight average) of this polypropylene is at nost auott 20,000, the polgmer is dvscxibzd as hwvinj iormal (at 20.degree. B.) viscosity ranging from that of a light lbbricating oil to that of
, an aluminum alkyl), and a compound transition of Groups of the Periodic halide). typical crystallinity is 60% as measured X-ray diffraction. As used herein, semi-crystalline a crystallinity of at least about 5-10% as measured by X-ray diffraction. Also, typical weight average molecular weight (Mw) of the normally solid polypropylene of commerce 100,000-4,000,000, the number molecular weight (Mn) thereof is 40,000-100,000. Moreover, the melting point of the normally solid polypropylene of is about 162.degree. C. Although the polypropylene of has many desirable and properties, it is deficient in strength. molten, it no hardening increase in resistance stretching during elongation of the molten material). Thus it has a variety of melt processing shortcomings, including onset of during high extrusion of or other substrates, and local thinning in melt thermoforming, in coextrusion of laminate structures. As a result, use has limited in such potential applications as, example, extrusion coating, blow molding, profile extrusion, and On the other hand, low density polyethylene made by a free radical process has desirable for applications that require strength or strain properties. low polyethylene believed to these properties because the polymer molecules are non-linear. The molecules are of ethylene units that have branches of ethylene units. This occurs of typical free inter- and intra-molecular transfer by subsequent polymerization. Low molecular (predominantly polypropylene molecular is in the prior art. Fontana, Kidder and Herold, Ind. Eng. Chem., 44 (7), Pat. No. 2,525,787, to Fontana et al. It disclosed as having been made by Friedel-Crafts However, the molecular weight (weight average) of this polypropylene is at most 20,000, the described as having normal (at 20.degree. C.) viscosity from that of a lubricating oil to that of
, an aluminum alkyl), and a compouNd of a transItion MetAl oF GRoupS IV-ViII of the PeriodIC TabLe, (for example, a titanium hAlide). a tYPicaL CrYstalLinity iS AbOUT 60% as MeAsUreD bY x-rAy difFraCtion. As Used herein, SemI-cRystalline meANs A crystalliNitY of at least abOut 5-10% As measUrEd bY x-ray dIffRactiOn. Also, THe typiCal weight AvERage moLEcular wEIGhT (Mw) oF the normally solid POlYPropylene of comMerce iS 100,000-4,000,000, wHIlE THe tYpiCal number aVeRage mOLecular WEiGHT (mn) tHEreof is 40,000-100,000. MoreovEr, the meltinG PoiNt of thE nOrmALly solId polYpROpyLene of commeRce iS about 162.degRee. C.
AlTHough thE PolyproPylene Of cOmmErce HAs MaNy dEsIRabLE aNd bENefIcial proPeRtIes, it Is deFICIEnt iN meLt stRengtH. When molten, it ExhIbitS No sTrain HardeNing (An IncreAse in rEsistAnCe to stretching dUrinG elongatiOn oF tHe mOlTen maTErial). THus It hAs a variEty of meLT prOcESSInG shortcomings, incluDiNG ThE onset of Edge weAVe DuRIng high sPeEd eXtruSIOn coaTing OF pAper or otHer subSTrAtEs, sheet SaG and loCaL thInnIng in MElt tHermofOrming, anD flow INstabilities in COextrusion of lAMiNATe STrucTurEs. As a result, Its uSE has Been LImIteD In sucH poteNtIAl APplications as, for exaMpLe, extrUsion Coating, blow moLding, profiLE EXtrusion, And tHErMOforming.
On the oTher hAnd, low densITy polyetHylenE made by a Free radicAL Process hAs dEsiRabLe mELT rHeology for appLICatiOnS that reQuiRe melt sTreNgtH or StrAiN hardeninG propertIeS. SUcH lOw dEnsitY PolyethyLeNe iS bEliEved tO Have thEse prOperTiEs BEcaUse the pOLyMER molEcUlEs arE noN-lInear. the mOLecUles are Chains of eThyLEne uNiTs That havE branches of etHyLene units. THiS noN-lineaR STructure Occurs because of typical fREe radicAl iNter- aNd inTra-molecuLar TransfEr fOLlowed By furtHer suBsEquENT polyMERiZatIoN.
Low molecuLAR weIght, aMoRphoUs (predoMinantly atactic) polYProPylene with a brAncHed mOLEcUlaR StRUctUrE Is kNOWn in the prior art. see Fontana, kiDDeR and Herold, iNd. & ENg. chem., 44 (7), 1688-1695 (1952), and The U.S. PaT. No. 2,525,787, to fOntana eT al. It is diSclosed as HaVing BEEn mAde by FriedEl-Crafts Catalysis. hOweveR, ThE moleCulAr weigHt (WeiGht avErage) oF ThiS polyPropylEnE is at mOst abOuT 20,000, the polyMer is described as having nOrmal (aT 20.degrEe. C.) Viscosity RanGIng From that oF a liGht lubricaTinG oiL to thAt oF
, an aluminum alkyl), anda compound  of a  tr ans it ionmeta l of Groups IV - VIII  of the Periodic Table , (fo re xamp l e,  a ti taniumh al i d e).  A  t ypi ca l  c rysta lli nity is  about 60%  as  m easured by X - ra y diffract ion . As used he rei n, sem i- cry s talli nemeans  a cry s tallin ity of at  l e ast ab o ut 5-10 % as  mea sured by X-ray di f fr a ction. Also, t he typ ic a lw e igh t a verage mol ec ularw eight ( M w) o f  th e  normally sol id polyprop y len e of c om mer c e is 1 00,00 0- 4 ,00 0,000, whil e th e typical  numbe r  averag e  molecu lar we igh t ( Mn)t he re ofis 40, 0 00 -10 0 ,00 0. Moreo ve r,  themelt i n g poin t o f th e nor mally solid p oly prop y len e ofcomme rceis  abou t 162. degre e.  C.
Although th e po lypropyle neof  co mm erceh as man y d esi rable a nd bene f ici al p r op erties, it is defi ci e n tin meltstreng t h.  W h en molte n,  it  exh i b its n o st r ai n harden ing (a n  i nc rease i nresist an cetostret c hing  durin g elonga tiono f the molten m a terial). Thus it h as a va rie ty of meltproc e ssin g sh o rt com i ngs,inclu di n gt he onset of edge we av e duri ng hi gh speed extr usion coat i n g  of pape r or ot h er substrates,  shee t sag andl ocal thi nning  in melt  thermofo r m ing, and  fl owins tab i l it ies in coextr u s ionof  lamina testructu res . A s a  re su lt, its u se has b ee nli mi ted  in s u ch poten ti alap pli catio n s as,for e xamp le ,e xtr usion c o at i n g, b lo wmold ing ,profi le e x tru sion, a nd thermo for m ing. 
O nthe oth er hand, lowde nsity poly et hyl ene ma d e  by a fr ee radical process hasd esirabl e m elt r heol ogy for a ppl icatio nst hat re quiremeltst ren g t h ors t ra inha rdening pr o p ert ies.Su ch l ow dens ity polyethylene i s  be lieved to hav e t hese p ro per t ie s  be ca u set h e polymer molec ules are n on - li near. Them ole cu les are  chains  of e t hyleneunits tha t have br an ches o f e thylene un its. Thi s non-lin e ar st r uc tureocc urs be ca use  of t ypical fre e rad ical i nt er- an d int ra -molecul ar transfer followed by  furth er su bse quent pol yme r iza tion.
Low  mol ecular wei ght , a morph ous (pred omin a nt lya tacti c) p o lypropyle n ewit h abranched mo l e c ula r str uct u re isknow n in the prior ar t . See Fontana,  Kid d e r a ndH erol d,  Ind. & Eng. C hem ., 4 4 (7), 1 68 8-1695 (195 2), andth e  U.S.  Pat.No. 2, 525,787 , to Fontan a et  al . It is d isc lo s ed as h av in g  beenmade  b y Frie del-Cr a ftsc a talysis. However , the m olecu l arweigh t(weight aver age) of th is polyprop yleneis a t mos t about  2 0,000,  th epolymer is described  as h aving n or mal(at  20.de gree . C.) v isco si tyranging f r o mt ha to f a  lig ht lu br icat ing oil t o  that of 
, an_aluminum alkyl),_and a compound of_a transition_metal_of Groups_IV-VIII_of the Periodic_Table, (for example,_a titanium halide). A_typical crystallinity is_about_60% as measured by X-ray diffraction. As used herein, semi-crystalline means a crystallinity of_at_least about_5-10%_as_measured by X-ray diffraction. Also,_the typical weight average molecular_weight (Mw)_of the normally solid polypropylene of commerce is_100,000-4,000,000,_while the typical_number average molecular weight (Mn) thereof is 40,000-100,000. Moreover,_the melting point of the normally_solid polypropylene of_commerce_is_about 162.degree. C.
Although the_polypropylene of commerce has many desirable_and beneficial properties, it is deficient_in melt strength. When molten, it exhibits_no strain hardening (an increase in_resistance to stretching during elongation_of the_molten material). Thus it has_a variety of_melt processing_shortcomings, including the_onset of edge weave during high_speed extrusion coating_of paper or other substrates, sheet_sag_and local thinning_in_melt_thermoforming, and_flow instabilities in_coextrusion_of laminate_structures._As a result, its use has_been_limited in such potential applications as, for_example, extrusion coating, blow_molding,_profile extrusion, and thermoforming.
On_the other hand, low density_polyethylene made by a free radical_process has_desirable melt_rheology for applications that require melt strength or strain hardening properties._Such low density polyethylene is believed_to have these properties_because the_polymer_molecules are non-linear._The_molecules are_chains of ethylene units that have branches_of ethylene_units. This non-linear structure occurs because_of typical free radical_inter-_and intra-molecular transfer followed by further_subsequent polymerization.
Low molecular weight, amorphous (predominantly_atactic) polypropylene with a branched_molecular_structure_is known in the prior_art. See Fontana, Kidder and Herold,_Ind. & Eng._Chem., 44 (7), 1688-1695 (1952), and the_U.S._Pat. No. 2,525,787, to Fontana et_al._It is disclosed as having been_made_by_Friedel-Crafts catalysis. However, the molecular_weight (weight average) of this polypropylene_is at most about 20,000, the polymer is described_as having normal_(at 20.degree. C.) viscosity ranging_from_that_of a light lubricating oil to that of