CA1192349A - Polybutylene - Google Patents
PolybutyleneInfo
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- CA1192349A CA1192349A CA000422652A CA422652A CA1192349A CA 1192349 A CA1192349 A CA 1192349A CA 000422652 A CA000422652 A CA 000422652A CA 422652 A CA422652 A CA 422652A CA 1192349 A CA1192349 A CA 1192349A
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- polybutylene
- elastomeric
- isotactic
- butene
- polymers
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Abstract
POLYBUTYLENE
Abstract of the Disclosure A novel product of the polymerization of butene-l is highly stereoregular but nevertheless has low crystallinity and has properties of a thermoplastic elastomer.
This elastomeric polybutylene is the total product. Its elastomeric qualities lie between those of plasticized vinyl polymers and conventional vulcanized rubbers.
The butene-l polymers may be compounded with extenders and fillers for use as molded or extruded elastomeric product or may be used without plasticizer addition in place of flexible vinyl polymers, such as highly plasticized poly(vinylchloride)(PVC).
Abstract of the Disclosure A novel product of the polymerization of butene-l is highly stereoregular but nevertheless has low crystallinity and has properties of a thermoplastic elastomer.
This elastomeric polybutylene is the total product. Its elastomeric qualities lie between those of plasticized vinyl polymers and conventional vulcanized rubbers.
The butene-l polymers may be compounded with extenders and fillers for use as molded or extruded elastomeric product or may be used without plasticizer addition in place of flexible vinyl polymers, such as highly plasticized poly(vinylchloride)(PVC).
Description
349 K-4438 G (CA) MSB:dl POLYBUTYLENE
Fîeld of the Invention -This invention relates to novel polymers of l-butene.
Background of the Invention Thermoplastic, predominantly isotactic homo- and copolymers of l-butene3 referred to herein and in the trade as "polybutylene" or "poly-l-bu~ene," are well known materials. Isotactic polybutylene is the subject of U.S. Patent 3,435,017 of Natta et al. The properties and preparation of isotactic polybutylene are described, for example, in "Encyclopedia of Chemical Technology," edited by Kirk-Othmer, 2nd Ed., Suppl. Vol., pp. 773-787. Methods for producing such polybutylene are disclosed, i.a., in U.S. Patents 3,362,940 ancl 3,464,962. Thermoplastic, predominantly isotactic butene-1 homopolymers of the type heretofore described in the literature, e.g., in U.S. Patents 3,362,940 and 3,435,017, and produced commercially, are referred to herein as "conventional"
polybutylene.
Conventional polybutylene is produced by contact of l-butene with coordination catalysts which are generally referred to as Ziegler-Natta catalysts. Broadly, such catalysts are the products o-f contacting a compound of a transition metal of Group IV of the Periodic lable of Elements or of some other transition metals with an organometallic compound of a metal of Groups I-III.
For convenience of reference herein, the transition metal-containing components, which are typically solid, are referred to as "procatalysts", the organometallic compounds as "co-ca~alysts", and any additional stereoregulating compounds as "selectivi~y control agents", abbreviated "SCA".
Commercial ~iegler-Natta catalysts are designed to be highly stereoregulating in order to produce highly isotactic polyolefins~
Several generations of Ziegler-Natta coordination catalysts have acquired commercial importance in the production of isotactic poly-olefins Originally, a typical procatalyst was violet TiC13 in the delta or gamma crystal form, or a violet TiCl3 complex, such as w~
~L~9~34~9 AlCl3. Several types of more active TiC13 procatalysts have since been developed and put to commercial use. The co-catalysts employed with TiC13 catalysts are aluminum alkyl compounds, typically halogen-containing aluminum alkyls such as aluminum diethyl halides.
During the last 10 years, more highly active catalyst systems have been developed, particularly for production of isotac~ic polypropylene.
These typically comprise a support of magnesium chloride, which may have been activated such as by ball milling, combined with TiCl~ and an electron donor--typically an aromatic ester such as ethyl benzoate. The co-catalyst is again an aluminum alkyl, typically an aluminum trialkyl.
Generally an electron donor is employed as selectivity control agent.
The cocatalyst may be complexed with the selectivity control agent in whole or in part, prior to being combined with the procatalyst. The purpose of the selec~ivity control agents is to increase the stereoregulating activity of the catalysts. Typical selectivity control agents are aromatic esters such as p-ethyl anisate. Numerous variants of these systems have been disclosed in the patent literature. These catalyst systems, referred to herein as supported coordination catalyst systems, are known to be substantially more active in the production of polypropylene than the most active TiCl3-based catalyst systems of the prior art.
The goal of commercial Ziegler-Natta catalysis of propylene or higher alpha-monoolefins generally is the production of highly isotactic polymers. Isotaoticity refers to the molecular structure of olefin polymer molecules. The isotactic structure in polyolefins is one in which all the assyme~ric carbon atoms have the same steric configuration.
The isotactic structure of polybutylene is illustrated and discussed in U.S. Patent 3~435~017 to Natta et al. High isotac~ici~y of conventional polymers of butene-l or of prspylene is associated with high crystallinity of the polymers.
The crystallinity of conventional butene~l-homopolymers, determined by X-ray diffraction analysis, is typically ln the range from 50 to 55%. Their isotacticity9 determined by ether extraction~ is typically in the ranye from 97.5% to 99.5%.
~23~
Another highly stereoregular form of polyolefins is known as "syndiotactic". In the syndiotactic structure, alternate assymetric carbon atoms have opposite steric configurations. Syndiotactic poly-butylene is described by Natta et al in Atti Acad. Naz. Lincei, Cl. Sci.
Fis, Mat. Nat., Rend. [8~ 28, 452 (1960). The polymer is an amorphous solid. It was prepared by hydrogenation of syndio-tactic polybutadiene.
Syndiotactic polyolefins are difficult to produce and are not at present of commercial interest.
~ ue to its crystallinity, conventional polyb~tylene exhibits ~o signi~icant stiffness, tensile strength, hardness, and other physical properties characteristic of such polymers as high density polyethylene and isotactic polypropylene. It also shares such other properties of these polyolefins as chemical inertness and dielectric properties.
Outstanding properties o~ conventional isotactic polybutylene are toughness, resistance to creep and resistance to environmental stress cracking. The e~ceptional resistance of polybutylene to enYironmental stress cracking, coupled with the good creep resistance, recommends the use of conventional poiybutylene for pipe. The exceptional toughness makes it desirable for the production of film ~or packaging, since films of conventional polybutylene are significantly stronger than films of other common polyolefins of the same thickness.
~lastomeric polybutylene recovered as a small ~raction of a product made with poorly stereoregulating catalysts is known from U.S.
Patent 31435~017 to Natta et al. Another elastomeric polybutylene, having an isotacticity of no more than 50% and produced with a catalyst having poor stereoregulating activity, is the subject of U.S. ~,298,722 to Collette et al.
References "Encyclopedia of Chemical Technology~" Kirk-Othmer~ 2nd Ed., Suppl. Vol., pp. 773-797 provides a detailed deseription of the state o~
the art of polybutylene production in 1967; the commerc;al aspects have not significantly changed to date.
U.S. Patent 3,435,017 to Natta et al describes conventional isotactic polybutene-l and its preparation and properties.
U.S. Patent 3,175,999 to Natta et al describes polymers of alpha olefins, primarily of propylene, which are designated "stereoisomer"
block polymers. They are descrihed as polymers in which isotactic sections alternate with non-isotactic (atactic) sections. Stereoblock polymers are said to be present in small concentrations in conventionally prepared Ziegler-Natta polymers; they must be recovered by a series of solvent extractions, as by treating some of the intermediate fractions of a sequential solvent extraction of Ziegler-Natta polymers with a solvent which has a dissolving capacity for the polyolefin intermediate between that of diethyl ether and n-heptane. In the illustrative examples, the catalysts are compositions which are now known to have poor or very poor stereoregulating ability. In Example 4 of the patent, a polymer of butene-l, produced with a catalyst prepared from vanadium tetrachloride and triethylaluminum, was extracted with hot ether and the residue of the ether extraction was then extracted with methylene chloride to obtain an extract, corresponding to 6% of the residue o~ the first extraction, which was said to have high reversible elasticity.
U.S. Patent 4,298,722 to Collette et al is directed to production of an elastomeric polybutene-l whieh is made with a poorly stereoregulating catalyst and has an ether solubles content of at least 30% and isotacticity not excee~ing 50%. The reaction products illustrated by example, listed in Table 3 of the patent, had ether solubles contents of 38-56% (determined before milling) and isotacticities of 23-46%.
A large number of patents an~ patent applications have now been published directed to the production of supported coordina'cion catalyst syst~ms -For the ster~oregular polymerization of alpha olefins;
~he following ~hree patent publications are specifically directed to ~he polymerization of butene-l.
European Pu~lished Patent Application 2522, published June 27, 1979, of Phillips Petrole~m Company, is directed to the polymerization oF butene-l to form a polybutylene having the properties oF conventional 34~
isotactic polybutylene. In order to accomplish this, the patent describes a modified catalyst preparation and a particular slurry polymerization process.
Japanese Kokai Patent No. 54/85293, published July 6, 1979, applied for in Japan on December 21, 1977 by ~itsui Petrochemical Industries Company, is directed to the production of certain copolymers of butene-l with another alpha monolefin, having more than 60 but no more than 98% weight butene-l content and preferably 70-90% butene-l content and 30-10% propylene. These copolymers are said to have physical characteristics comparable to polyvinyl chloride.
Japanese Patent Application 51/23607 published September 24, 1980, applied for in Japan by Mitsui Petrochemical Industries Company, is directed to a modification in the polymerization process for producing conventional polybutylene over catalysts employing as procatalysts a composite of titanium, magnesium, halogen and electron donor.
Summary of the Invention This invention is directed to a product of the polymerization of butene-l which has high stereochemical order but nevertheless has low crystallinity and has properties oF a thermoplastic elastomer. The polymer product of this invention is the total product, or substantially the total product, of homopolymerization of butene-l over highly stereo regulating coordination catalysts. The butene-l polymers of this invention are referred to herein as elastomeric polybutylene.
This product is characterized by an abrupt and discontinuous change in mechanical properties compared to conventional isotactic poly-butylene. The properties of the latter are those of conventional thermo-plastics while the product of this invention is elastomeric. This reflects a change from a level of crystallinity where the crystalline portion of the polymer dominates mechanical properties to a level where the amorphous phase dominates mechanical properties. Moreover, similarly to thermoplastic elastomer block copolymers, the polymer product of this invention behaves like a phys~cally crosslinked elastomer, l~eO, it behaves as if its elastomeric amorphous phase is bound together through 3~
a network of crystalline domains. Its elastomeric qualities lie between those of plasticized vinyl polymers and conventional vulcanized rubbers.
Like thermoplastic elastomers such as the well known cor~mercia7 block copolymers based on styrene and diolefins or complex blends of polypropylene with elas~omeric copolymers of ethylene and propylene, the butene-l polymers of this invention may be compounded with extenders and fillers for use as molded or extruded elastomeric products. The butene-1 polymers of this invention are also useful for those uses where flexible vinyl polymers, such as highly plasticized poly(vinylchloride) (PVC), have heretofore been employed. Unlike PVC, they do not require the use of plasticizers to achieve and retain the desired flexibility.
They also do not have the disadvantages of potential health and sa-fety problems associated with vinyl chloride monomer, with burning of PVC and with PVC plastic;zers.
The elastomeric polybutylenes of this inven~ion possess an unusual combination of properties, compared to other thermoplastic elastomeric polymers, in that they combine the resilience and flexibility typical of elastomers with the surface hardness characteristic of thermo-plastic polyolefins such as conventional polybutylene.
Brief Description of the Drawing Figure 1 of the draw;ng shows 13C NMR spectra of conventional polybutylene and of elastomeric polybutylene of this invention.
Figures IA and lB are expansions of the peak at about 28 ppm, showing the fine structure in greater detail.
Figure 2 is a graph of damping curves of elastomeric poly-butylene of this invention, PVC and natural rubber.
Figure 3 is a plot of tensile yield strength v. ether solubles for elastomeric polybutylene and conventional polybutylene.
Figure 4 is a plot of hardness Yr flexibility as measured by Young's modulus, for elastomeric polybutylene9 PVC and conventional elastomers.
Figure 5 is a stress relaxation plot for elastomer-ic poly-butylene and for PVCs of diFferent plasticizer contents.
~ 6 --23~9) Figure 6 is a plot o~ data of a recrystallization procedure comparing elastomeric polybutylene of this invention with a polybutylene of relatively low stereoregulativity.
Description of the Invention Conventional polybu~ylene~ as produced in polymerization with effective Ziegler-Natta type coordination catalysts, typically has an isotactic content greater than 92%, as determined by extraction with boiling diethyl ether. It ~ypically exhibits a crystallinity of the order of 50-60% by X-ray diffraction analysis and has the tensile strength ~o and stiffness characteristic of highly crystalline thermoplastics.
Like conventional polybutylene, the polybutylene products of this invention also are highly stereoregular. However, unlike conventional polybutylene, the polybutylene of this invention nevertheless exhibits crystallinit~y in the ran~e of only 25-40% by X-ray diffraction analysis.
Even though it has high steric order, the polybutylene of this inYention exhibits physical properties characteristic of thermoplastic elastomers, such as the well known commercial block copolymers based on styrene and diolefins or complex blends of polypropylene with elastomeric copolymers of ethylene and propylene.
Z0 The elastomeric polybutylene o~ this invention is a total product of the homopolymeri~ation of butene-l, characterized by ~he following properties:
Solubility in refluxing diethyl ether, % wt ~ 10 Crystallinity, by X-ray diffraction (Form I3, % 25-40 Mn x 10-3 (a) 20-300 Mw x 10-3 (a) 150-2,200 Mw/Mn 4~~
Melting Point(b), Form I, C ~ lOQ-118 Melting Point(C), Form ~I, C ~ 98~110 Tensile Strength At yield, psi 40n-1700 At break, psi 3000-45Qo Elongation at break, % 300-6Q0 3~
~lardness, Shore A, 10 seconds 50-90 In fractional crystallization method A, described below, the resi~ue of ~he third recrystallization represents no more than about 25% of the total polymer.
(a) By gel permeation chromatography.
~b) By differential scanning calorimeter (DSC) at heating rate of 20C/minute, using compression molded plaque, crystallized at 7C; after transformation to Form I.
(c) By DSC after crystallizing the melt at 10C/minute cooling rate and then immediately heating a~ 20C/minute.
In the preferred products of this invention, the total unextracted reaction product contains no more than 8%, and still more preferably no more than 5% of ether soluble components. The total polymerization products may be used without extraction or aFter extraction of all or a portion of the small ether soluble fraction, which owes its solubility to a combination of low steric regularity and low molecular weight.
Products of this invention having ether solubles contents close to the upper permissible llmit may exhibit some degree of surface adhesion or stickiness. For so~e uses, e.g., as film or sheet, this may make it desirable to extract some or all of the ether so'luble portion. For other uses, e.g., for blending with other polymers, the presence of a small ether-soluble component may not be objectionable. Products having ether solubles content in the preferred lower ranges do not exhibit significant surface adhesion or stickiness even though they contain a large proportion of polymer soluble in boiling n-heptane, whereas polybutylenes produced with a relatively non-stereoregulating conventional coordination catalyst, which also exhibit relatively low crystallinity and are also relatiYely flexible compared to conventional polybutylene, exhibit high surface adhesion, resulting from a large fraction of low steric regularity.
A prominent feature of our elastomeric polybutylene is its substantially suppressed level of crystallinity compared to conventional polybutylenes. A companion ~eature of our elastomeric polybutylene, one which makes it unique among the large number of polyolefins produced with s~ereose'lective catalysts, is the fact ~hat this suppression of ~z~
crystallinity is achieved without the corresponding large increase in amount of easily extractable polymer (soluble in refluxing ethyl e-ther) which results when the crystallinity enhancing features o~ a conYentional Ziegler-Natta polymeri~ation system are removed or reduced. This is shown by the dramatically di~ferent correlation between extractable polymer concentration and tensile strength shown by our elastomeric polybutylene compared to conventional polybutylene as illustrated in Figure 3. The origin of this unique relationship appears to lie in the co-enchainment of the isotactic sequences and sequences of frequent, mostly alternating (syndiotactic), tactic inversions of elastomeric polybutylene. On the other hand, stereoirregular species in conventional polybutylene largely coexist as separate fractions which are easily separable by extraction with ether.
Another distinguishing feature of our elastomeric polybutylene is its 13C NMR spectrum. The 13C NMR method provides detailed in-formation about the con-Figuration and conformation of short sections of polymer chains. A comparison o~ 13C NMR spectra of conventional polybutylenes with those of the products of this in~ention indicates a significant di~ference between the products, even though they both have a very high degree of steric order. The dif-ference shows up as a higher proportion of polymer comprised of short sequences of Frequent tactic inYersion alternating with 10nger isotactic seq~ences. This indicates for the products of this invention a s~ructure o-F short average isotactic sequences, which contrasts strikingly with the long average isotactic sequences of conventional polybutylene.
The enchained tactic defect structure which alternates in a stereoblock structure with isotactic sequences in elastomeric polybutene-l is responsible ~or 'che fine s~ructure associated ~ith the ~najor 13C NM~
absorptions o~ polybutene-l. As evident in Figure l and lB, this fine structure is much more prominent in the spectrum oF elastomeric polybutene-l than it is in conventional polybutylene ~lA~. Integrated intensities o~ the absorbances in the 26 to ~8 ppm region show 15% tactic defect structure associated wikh very short tactic inversion sequences (~ 5 Inonomer uni~s) g ~323~
and 9% alternating (syndiotactic) tactic inversions in sequences ~ S
monomer units. By comparison, typical conventional polybutylene has only 6% defect structure and 2% alternating or sydiotactic sequence stereo-structure. It is the larger amount of the net defect structure, enchained in not readily extractable molecules, that accounts for the elastomeric character of our new form of polybutylene.
13C NMR spectra of the fractionated polybutenes were recorded on a Bruker WM-360 spectrometer operating at 90.50 MHz under proton decoupling in FT mode. Instrument conditions were: 90 pulse of 50 ~s, 9 s repetition rate, 14 KHz sweep width and 32 K FID. The numbers of transients accumulated were 1500 to 3000. Solutions of polymers were rnade up in 15mm tubes with 0.5 to 1.0 9 per 5 cm3 of 2,2,4-~richlorobenzene with N2 degassing. Temperature for measurement was 130C. The chemical shift was presented in ppm down field from TMS as an external standard.
Like all products of olefin polymerizations with coordination catalysts, the products of this invention are mixtures of molecules differing from each other to some extent in structure and in molecular weight. The compositions and structures of such products are to some extent a function of the specific catalyst composi~ions and reactions conditions employed in their production.
The elastomeric polybutylene of this invention may be produced having a wide range of molecular weights. ~umber average molecular weights (Mn) may be from 20,000 to 300~000 and weigh~ average molecular weights (Mw) from 150,000 to 2,200,000. A characteristic of the products of this invention is a narrow molecular weight distribution, as indicated by ~he ra~io of ~iW/Mn (Q-value) which is typically of the order of 70 to 75%w or less of the Q~value of conven~ional polybutylene.
Both conventional and elastomeric isotactic polybutylene are unique compared to other commercial polyolefins in that they are capable of existing in seYeral crystalline modificatlons which can be isolated in almost pure forrn. Conventional isotactic polybutylene typically first solidifies from the mel~ in the crystal form known as Type II. Type II
is unstable with respect to Type I and converts to T~pe I at a rate ~23~
depending on a variety of factors, such as molecular weight~ tacticity, temperature, pressure, and mechanical shock Properties of the seYeral crys~al forms oF conventional isotactic polybutylene are well known.
The transformation of Type II to Type I has a marked effect on the physical properties. Density, rigidity and strength are increased.
Like conventional polybutylene, our elastomeric polybutylene crystallizes from the melt in the form of crystal Type II, which transforms to crystal Type I over a period of hours or days, depending on environmental conditions.
Physical properties of elastomeric polybutylene of this invention, crystallized in Type I form, are shown in Table 1. Also shown in Table ls for comparison, are corresponding properties of a butene-l homopolymer produced on a commercial scale in a solution process.
Table 1 Conventional PBElastom ric PB
Range Range Typical Solubility in refluxing diethyl ether, % ~t. 0.~-2.5 ~ 10 1.5-8 Crystallinity~ % 50-60 25-40 30-35 ~n x 10- 25-95 20-300 50-200 Mw x 10-3 ~230-1540 150-2200 500-1500 Mw/Mn 10-12 4-8 6-7 Melting Point~ Form I, C 123~126 ~100-118 ~106-116 Melting Point~ Form II, C 113-117 ~38-110 ~100-107 Tensile Properties Tensile strength at yield, psi2200-2600 400-1700 Tensile strength at break, psi~500-5500 3000 4500 Elongation at break 200-375 300-600 Hardness, Shore A, 10 sec. 50-90 75-87 The elastomeric character of polybutylene of this invention is demonstrated in Figure 2 of the drawing, which shows damping curves of a typ;cal plasticized PVC, of vulcanized natural rubber, and of a typical elastomeric polybutylene. Damping curves were determined by a free 3~
vibration torsion pendulum. Since the damping effect varies with the softness of the product it is accepted practice to recalculate damping curves for a product of uniform Shore Hardness. The curves in Figure 1 are normalized for product of 75 Shore Hardness, Method A (1 second).
The ordinate is amplitude and the abscissa is time in centiseconds.
The elastomeric polybutylene is shown to be more elastomeric than plasticized PVC, but less so than natural rubber.
Figure 3 is a plot of tensile yield strength in pounds per square inch Yersus ether solubles content in percent by weight, it illustrates the difference between the elastomeric polybutylene of this invention and conventional polybutylene.
Area A represents a range of values measured on elastomeric polybutylene of this invention. Line I represents an average curve for these values. Line II represents average values of conventional poly-butylenes.
Figure 4 illustrates how polybutylene of this invention differs uniquely from conventional elastomers in exhibiting a greatly superior surface hardness at a given flexibility. It is a plot of hardness versus Young's modulus. Hardness is plotted as Shore Hardness, Method A, 10 seconds. Curve I is an average curve representative o-f commercial PYC9 containing varying amounts of plasticizer ~o achieve varying degrees of flexibility. Area A represents a range of values for uncompounded elastomeric polybutylene of ~his invention. Curve II is an average curve of ~alues obtained with different compounded elastomers, both vulcanized SBR and thermoplastic block copolymersg which are identified on the drawing.
While uncompounded polybutylene of this invention has certain properties which are close to those of compounded PVC, as shown in Figure 4~ it also has uniquely advantageous properties compared to PVC.
This is illustrated ;n Fi~ure 5.
Fi~ure 5 relates to stress relaxation. Curve ~ is measured on a polybutylene according to this invention and curYes II, II' and II" on samples of commercial PYC con~aining different amounts of plasticizer 3~
and having nominal hardness ~alues of 40, 65 and 95, respectiYely. The stress relaxation test is conducted by stretching a specimen to 300% of elongation and observing the decrease ;n stress as a function of time.
In Figure 5, the abscissa is a logarithmic scale of time in seconds and -the ordinate is the percent of the initial stress at a ~iven time.
It is seen that elastomeric polybutylene of this invention has a relatively low rate of stress relaxation. This property is particularly desirable in products to be used for seals, gaskets and the like.
Table 2 provides a comparison of representatiYe properties of a sample o~ uncompounded elastomeric polybutylene of this invention with typical commercial PVC and elastomers. The elastomeric polybutylene was prepared as in Example 6.
Table 2 Uncompounded S-EB-SC) Thermoplastic Elastomeric ) b)ThermoplasticPolyurethane Poly~butylene PVCa EPDM Elastomer Elastomer ~ .
Tensile strength, at break, psi4000 1800 2000 6000 7000 Elongation at break, % 600 300 600 600 500 Tensile set at break, % 125 300 200 50 40 Hardness Shore A, 10 sec. 83 65 75 80 80 Young's Modulus, psi 6500 3000 4500 500Q 600 Stress recovery, %80 25 35 70 50 Hys~eresis loss, %60 60 70 45 55 Tear resistance~
30lbs/linear inch1100 6Q0 450 500 700 Resilience, % 75 35 45 80 70 Processing temperature, F 350 350 450 500 500 . .
(a) PVC plasticized with about 40% wt dioctyl phthalate (b~ Mineral filled, vulcanized (c) Uncompounded (d~ Pol~yether based ';
39~
The unique composition of elastomeric polybutylene of this invention, Gontrasted with conventional polybutylene which has been prepared at conditions leading to lower average isotacticity is demonstrated by fractional crystallization of the whole polymer from n-heptane. The method is regarded as representing a fractionation with respect to crystal-lizabilîty of the polymer, which in turn is believed to be determ-ined by the distribution of isotactic sequences and tactic inversions in the polymer molecules. The procedure, referred to herein as fractional crystallization Method A~ is carried out as follows:
100 grams of the total polymer is dissolved in 1 liter of n-heptane at 50-60C. The solution is cooled to ambient temperature of about 25C and allowed to stand ~or at least 24 hours, to permit complete precipitation of the polymer portion which is crystallizable at those conditions. The solid fraction is filtered oif, washed with 1 liter of n-heptane, dried and weighed. The soluble -Fraction is recovered from ~he combined filtrate and wash liquid by evaporation o~ the solvent and weighed. The procedure is repeated with the total ~irst precipitate and repeated twice more with the successive precipitates, using the same amount of n-heptane and the same conditions.
It has been found that in fractional precipitation of a typical polybutylene oF this invention by this method, the percent by weight of the total polymer which remains dissolved in each stage is of the order of 25% o~ the total polymer. ~y contrast9 when the same procedure was carried out on a conventional polybutylene which had been prepared with poorly stereoselective catalysts, and which had an et'ner extractable content of ~2.2%, the amount of polymer which rema-ined in the first filtrate was abo~t 27%wt. but decreased to abo~t 16%wt. and ~ 4%~t. in the second and third filtrates, leaving more than 50%~tO as residue of the th;rd recrystallization. These results are graphically illus~rated in Figure 6, which is a plot of cumulative amounts dissolved Yersus number of recrystallization steps.
Crystallization method ~, carried out on conventional polybutylene, showed less khan 4% soluble in ~he first recyrskalli~ation and essentially none in the later recrystallizations.
~3~3~
There are various theories with respect to the mechanism of polymeriza-tion over Ziegler-Natta catalysts. A widely held view is that the selectivity of Ziegler-Natta catalysts in alpha-olefin poly-merization is simply a ~unction of the relative populations of selective (isotactic) and non-selective (atactic) sites on the procatalyst.
Accordingly, the isotacticity of a given unextracted polymer i5 considered to be determined by the relative proportions it contains o~ highly isotactic product polymerized at selective sites on the procatalyst and highly heterotactic ~atactic) product polymerized at non-selective sites. The heterotactic fraction is non-crystallizable or only very slightly crystallizable and can be separated from the isotactic portion of the whole polymer by solvent extraction, e.g., in boiling n-heptane, as typically employed for polypropylene, or in boiling diethyl ether~
typically employed for polybutylene. The amount of extractable polymer is the most commonly used indication of the select1vity of the ca~alyst and the isotactic purity of the polymer. Selectivity control agents which are employed in many commercial Ziegler-Natta systems to control isotacticity and hence crystallinity are regarded as preferentially deactivating non-selective catalyst sites.
We now believe that there is an additional dimension of stereo-selectivity. This additional dimension has to do with the ability of some cata~lyst sites to exist for shor~ durations in a mode ~hich produces alternatin~ tac~ic inversions in polymer molecules produced at otherwise jsotactic selective sites. The inversions or short sequences of mostly alternating inversions (syndiotactic sequences) interrupt runs of isotactic sequences~ producing isotactic blocks which are longer or shorter, depending upon the ~requency or rate of inversion in relation to the rate of polymeri~ation propagation at the particular active catalyst site. The isotactic stereoblocks will be long for catalysts where population of such dual mode sites is small and/or where the ratio kiSotactic!kinyersion is large, and/or where the time spent by a dual mode si~e in the inversion or syndiotactic mode is small Such is the predominant situation in conventional Ziegler-Natta catalysis; the stereoblocks w-ill be shorter for catalyst where these situations are reYersed.
We have discovered that under certain operating conditions supported coordination catalyst systems appear to fall in the latter category in the polymerization of butene-l, as indicated by 13C NMR
analysis of the polymer products. Thus, the steric purity of polybutylene produced in such polymerizations appears to be not just a function o~
the relative proportions of isotactic and atactic catalyst sites but also a sensitiYe ~unction of what appears to be highly specific chemistry leadin~ to tactic inversions at isotactic sites.
Natta et al described certain stereoisomer block copolymers jn lJ.S. Patent 3,175,999 as polymers in which isotactic sections alternate with atactic sections. The stereoisomer block copolymers were produced, as illustrated in the examples, with catalysts which have poor ability to produce isotactic polymers, and represented only small proportions of the total polymer product. In contrast to this, our elastomeric polybutylene can be produced as the total polymerization product by means of catalysts which are capable o~ being highly stereodirecting for the production of isotactic polymers. Our polymers may be produced by means of catalyst systems which, when employed in propylene polymeri~ation, produce highly crystalline isotactic polypropylene. Our elastomeric polybutylene consists mainly of isotactic blocks, interrupted by inversions oF only one or a few molecules largely in alternating (syndiotactic~ stereochemical configurationsO
The preferred catalyst to be employed for production of elastomeric polybutylene of this invention is one in which the solid component comprises a support o~ magnesium chloride in an active ~orm, combined with an electron donor and titanium halide; typically the componen~s are MgC12, TiC14 and an aromatlc ester~ e.g., ethyl benzoate or p-ethyl toluate. This solid component is combined with an alumlnum alkyl, typically a trialkylaluminum such as triethyl aluminum and a selectiYity control agent, typically ethyl anisate. Numerous Yariants o~ these catalysts are described in recent patents7 such as U.S. Pa~ents Nos.
~ ~23~
4,051,313, 4,115,319, 4,235,9~ and 4,250,287. Preferred to da~e arecatalysts prepared as described in U.S. Patent ~,329,253 to Goodall et al and in European Patent Application 19,330, published November 26, 1 9~0.
The conditions under which the polymerization is conducted, including the method of combining the catalyst components, can also affect the type of polymer produced. In a preferred method, all three catalyst components are pre-mixed before being introduced into the polymerization zone, and the procatalyst and cocatalyst are combined before the electron danor is combined with the catalyst mixture.
The polymerization is preferably conducted as a solution poly-merization process, using butene-l as the reaction medium. However, it may be conducted in liquid butene-l at conditions under which the polymer is produced as a solid in a so-called slurry polymerization. The poly-merization may be carried out in batch or continuous modes.
Suitable ratios of the several catalyst components are as follows-Ti content o^f procatalyst, ~wt. 1 - 5 Al:Ti atomic ratio ~ 50-150; preferably about 65-100 SCA:Ti molar ratio > 4.5-20, preferably about ~.5-15 Al:SCA molar ratio 5:1-15:1 H2:Ti molar ratio 0-2500 The interaction of procatalyst, cocatalyst~ selectivity control agent and hydrogen in the production of iso~actic polymers is basically the same in the production of elastomeric polybutylene as it is in the production of other isotactic polyolefins. However, i~ has been observed that the molar ratio of cocatalyst to ~itaniumS when using appropriate amounts of SCA, is preferably not above 100 and should not exceed ahout 150. At ratîos approaching and exceeding 150, the polymer product gradually becomes less elastomeric and more nearly like conventional polybutylene.
The catalysts employed in the production of elastomeric poly-butylene may be of sufficiently hi~h activity that no product deashing step is required. If catalyst residues are to be deactivated and removed, this may be accomplished by conventional means employed in cleanup of olefin polymers produced over such catalysts, e.g., by contact with an alcohol, followed by extraction with water.
The elastomeric polybutylene of this invention, which combines the chemical properties of polybutylene with physical characteristics resembling those oF plasticized PVC and of thermoplastic elastomers, is expected to find many uses.
Unblended products of this invention are relatively homogeneous materials of excellent chemical resistance as well as physical toughness.
Polybutylene of this invention has been converted into films, including heavy gauge film use~ul for bagging of industrial powdered goods. It is also useful for conversion into stretchable plastic -Fibers and filaments.
For applications in which thermoplastic elastomers have hereto-before been employed, the products of this invention can be compounded and processed similarly to conventional hydrocarbon elastomers, e.g., by blending with other polymers such as polypropylene7 with extenders such as mineral oils and waxes, and with fillers such as calcium carbona~e, for use as molded or extruded products in various applications for which
Fîeld of the Invention -This invention relates to novel polymers of l-butene.
Background of the Invention Thermoplastic, predominantly isotactic homo- and copolymers of l-butene3 referred to herein and in the trade as "polybutylene" or "poly-l-bu~ene," are well known materials. Isotactic polybutylene is the subject of U.S. Patent 3,435,017 of Natta et al. The properties and preparation of isotactic polybutylene are described, for example, in "Encyclopedia of Chemical Technology," edited by Kirk-Othmer, 2nd Ed., Suppl. Vol., pp. 773-787. Methods for producing such polybutylene are disclosed, i.a., in U.S. Patents 3,362,940 ancl 3,464,962. Thermoplastic, predominantly isotactic butene-1 homopolymers of the type heretofore described in the literature, e.g., in U.S. Patents 3,362,940 and 3,435,017, and produced commercially, are referred to herein as "conventional"
polybutylene.
Conventional polybutylene is produced by contact of l-butene with coordination catalysts which are generally referred to as Ziegler-Natta catalysts. Broadly, such catalysts are the products o-f contacting a compound of a transition metal of Group IV of the Periodic lable of Elements or of some other transition metals with an organometallic compound of a metal of Groups I-III.
For convenience of reference herein, the transition metal-containing components, which are typically solid, are referred to as "procatalysts", the organometallic compounds as "co-ca~alysts", and any additional stereoregulating compounds as "selectivi~y control agents", abbreviated "SCA".
Commercial ~iegler-Natta catalysts are designed to be highly stereoregulating in order to produce highly isotactic polyolefins~
Several generations of Ziegler-Natta coordination catalysts have acquired commercial importance in the production of isotactic poly-olefins Originally, a typical procatalyst was violet TiC13 in the delta or gamma crystal form, or a violet TiCl3 complex, such as w~
~L~9~34~9 AlCl3. Several types of more active TiC13 procatalysts have since been developed and put to commercial use. The co-catalysts employed with TiC13 catalysts are aluminum alkyl compounds, typically halogen-containing aluminum alkyls such as aluminum diethyl halides.
During the last 10 years, more highly active catalyst systems have been developed, particularly for production of isotac~ic polypropylene.
These typically comprise a support of magnesium chloride, which may have been activated such as by ball milling, combined with TiCl~ and an electron donor--typically an aromatic ester such as ethyl benzoate. The co-catalyst is again an aluminum alkyl, typically an aluminum trialkyl.
Generally an electron donor is employed as selectivity control agent.
The cocatalyst may be complexed with the selectivity control agent in whole or in part, prior to being combined with the procatalyst. The purpose of the selec~ivity control agents is to increase the stereoregulating activity of the catalysts. Typical selectivity control agents are aromatic esters such as p-ethyl anisate. Numerous variants of these systems have been disclosed in the patent literature. These catalyst systems, referred to herein as supported coordination catalyst systems, are known to be substantially more active in the production of polypropylene than the most active TiCl3-based catalyst systems of the prior art.
The goal of commercial Ziegler-Natta catalysis of propylene or higher alpha-monoolefins generally is the production of highly isotactic polymers. Isotaoticity refers to the molecular structure of olefin polymer molecules. The isotactic structure in polyolefins is one in which all the assyme~ric carbon atoms have the same steric configuration.
The isotactic structure of polybutylene is illustrated and discussed in U.S. Patent 3~435~017 to Natta et al. High isotac~ici~y of conventional polymers of butene-l or of prspylene is associated with high crystallinity of the polymers.
The crystallinity of conventional butene~l-homopolymers, determined by X-ray diffraction analysis, is typically ln the range from 50 to 55%. Their isotacticity9 determined by ether extraction~ is typically in the ranye from 97.5% to 99.5%.
~23~
Another highly stereoregular form of polyolefins is known as "syndiotactic". In the syndiotactic structure, alternate assymetric carbon atoms have opposite steric configurations. Syndiotactic poly-butylene is described by Natta et al in Atti Acad. Naz. Lincei, Cl. Sci.
Fis, Mat. Nat., Rend. [8~ 28, 452 (1960). The polymer is an amorphous solid. It was prepared by hydrogenation of syndio-tactic polybutadiene.
Syndiotactic polyolefins are difficult to produce and are not at present of commercial interest.
~ ue to its crystallinity, conventional polyb~tylene exhibits ~o signi~icant stiffness, tensile strength, hardness, and other physical properties characteristic of such polymers as high density polyethylene and isotactic polypropylene. It also shares such other properties of these polyolefins as chemical inertness and dielectric properties.
Outstanding properties o~ conventional isotactic polybutylene are toughness, resistance to creep and resistance to environmental stress cracking. The e~ceptional resistance of polybutylene to enYironmental stress cracking, coupled with the good creep resistance, recommends the use of conventional poiybutylene for pipe. The exceptional toughness makes it desirable for the production of film ~or packaging, since films of conventional polybutylene are significantly stronger than films of other common polyolefins of the same thickness.
~lastomeric polybutylene recovered as a small ~raction of a product made with poorly stereoregulating catalysts is known from U.S.
Patent 31435~017 to Natta et al. Another elastomeric polybutylene, having an isotacticity of no more than 50% and produced with a catalyst having poor stereoregulating activity, is the subject of U.S. ~,298,722 to Collette et al.
References "Encyclopedia of Chemical Technology~" Kirk-Othmer~ 2nd Ed., Suppl. Vol., pp. 773-797 provides a detailed deseription of the state o~
the art of polybutylene production in 1967; the commerc;al aspects have not significantly changed to date.
U.S. Patent 3,435,017 to Natta et al describes conventional isotactic polybutene-l and its preparation and properties.
U.S. Patent 3,175,999 to Natta et al describes polymers of alpha olefins, primarily of propylene, which are designated "stereoisomer"
block polymers. They are descrihed as polymers in which isotactic sections alternate with non-isotactic (atactic) sections. Stereoblock polymers are said to be present in small concentrations in conventionally prepared Ziegler-Natta polymers; they must be recovered by a series of solvent extractions, as by treating some of the intermediate fractions of a sequential solvent extraction of Ziegler-Natta polymers with a solvent which has a dissolving capacity for the polyolefin intermediate between that of diethyl ether and n-heptane. In the illustrative examples, the catalysts are compositions which are now known to have poor or very poor stereoregulating ability. In Example 4 of the patent, a polymer of butene-l, produced with a catalyst prepared from vanadium tetrachloride and triethylaluminum, was extracted with hot ether and the residue of the ether extraction was then extracted with methylene chloride to obtain an extract, corresponding to 6% of the residue o~ the first extraction, which was said to have high reversible elasticity.
U.S. Patent 4,298,722 to Collette et al is directed to production of an elastomeric polybutene-l whieh is made with a poorly stereoregulating catalyst and has an ether solubles content of at least 30% and isotacticity not excee~ing 50%. The reaction products illustrated by example, listed in Table 3 of the patent, had ether solubles contents of 38-56% (determined before milling) and isotacticities of 23-46%.
A large number of patents an~ patent applications have now been published directed to the production of supported coordina'cion catalyst syst~ms -For the ster~oregular polymerization of alpha olefins;
~he following ~hree patent publications are specifically directed to ~he polymerization of butene-l.
European Pu~lished Patent Application 2522, published June 27, 1979, of Phillips Petrole~m Company, is directed to the polymerization oF butene-l to form a polybutylene having the properties oF conventional 34~
isotactic polybutylene. In order to accomplish this, the patent describes a modified catalyst preparation and a particular slurry polymerization process.
Japanese Kokai Patent No. 54/85293, published July 6, 1979, applied for in Japan on December 21, 1977 by ~itsui Petrochemical Industries Company, is directed to the production of certain copolymers of butene-l with another alpha monolefin, having more than 60 but no more than 98% weight butene-l content and preferably 70-90% butene-l content and 30-10% propylene. These copolymers are said to have physical characteristics comparable to polyvinyl chloride.
Japanese Patent Application 51/23607 published September 24, 1980, applied for in Japan by Mitsui Petrochemical Industries Company, is directed to a modification in the polymerization process for producing conventional polybutylene over catalysts employing as procatalysts a composite of titanium, magnesium, halogen and electron donor.
Summary of the Invention This invention is directed to a product of the polymerization of butene-l which has high stereochemical order but nevertheless has low crystallinity and has properties oF a thermoplastic elastomer. The polymer product of this invention is the total product, or substantially the total product, of homopolymerization of butene-l over highly stereo regulating coordination catalysts. The butene-l polymers of this invention are referred to herein as elastomeric polybutylene.
This product is characterized by an abrupt and discontinuous change in mechanical properties compared to conventional isotactic poly-butylene. The properties of the latter are those of conventional thermo-plastics while the product of this invention is elastomeric. This reflects a change from a level of crystallinity where the crystalline portion of the polymer dominates mechanical properties to a level where the amorphous phase dominates mechanical properties. Moreover, similarly to thermoplastic elastomer block copolymers, the polymer product of this invention behaves like a phys~cally crosslinked elastomer, l~eO, it behaves as if its elastomeric amorphous phase is bound together through 3~
a network of crystalline domains. Its elastomeric qualities lie between those of plasticized vinyl polymers and conventional vulcanized rubbers.
Like thermoplastic elastomers such as the well known cor~mercia7 block copolymers based on styrene and diolefins or complex blends of polypropylene with elas~omeric copolymers of ethylene and propylene, the butene-l polymers of this invention may be compounded with extenders and fillers for use as molded or extruded elastomeric products. The butene-1 polymers of this invention are also useful for those uses where flexible vinyl polymers, such as highly plasticized poly(vinylchloride) (PVC), have heretofore been employed. Unlike PVC, they do not require the use of plasticizers to achieve and retain the desired flexibility.
They also do not have the disadvantages of potential health and sa-fety problems associated with vinyl chloride monomer, with burning of PVC and with PVC plastic;zers.
The elastomeric polybutylenes of this inven~ion possess an unusual combination of properties, compared to other thermoplastic elastomeric polymers, in that they combine the resilience and flexibility typical of elastomers with the surface hardness characteristic of thermo-plastic polyolefins such as conventional polybutylene.
Brief Description of the Drawing Figure 1 of the draw;ng shows 13C NMR spectra of conventional polybutylene and of elastomeric polybutylene of this invention.
Figures IA and lB are expansions of the peak at about 28 ppm, showing the fine structure in greater detail.
Figure 2 is a graph of damping curves of elastomeric poly-butylene of this invention, PVC and natural rubber.
Figure 3 is a plot of tensile yield strength v. ether solubles for elastomeric polybutylene and conventional polybutylene.
Figure 4 is a plot of hardness Yr flexibility as measured by Young's modulus, for elastomeric polybutylene9 PVC and conventional elastomers.
Figure 5 is a stress relaxation plot for elastomer-ic poly-butylene and for PVCs of diFferent plasticizer contents.
~ 6 --23~9) Figure 6 is a plot o~ data of a recrystallization procedure comparing elastomeric polybutylene of this invention with a polybutylene of relatively low stereoregulativity.
Description of the Invention Conventional polybu~ylene~ as produced in polymerization with effective Ziegler-Natta type coordination catalysts, typically has an isotactic content greater than 92%, as determined by extraction with boiling diethyl ether. It ~ypically exhibits a crystallinity of the order of 50-60% by X-ray diffraction analysis and has the tensile strength ~o and stiffness characteristic of highly crystalline thermoplastics.
Like conventional polybutylene, the polybutylene products of this invention also are highly stereoregular. However, unlike conventional polybutylene, the polybutylene of this invention nevertheless exhibits crystallinit~y in the ran~e of only 25-40% by X-ray diffraction analysis.
Even though it has high steric order, the polybutylene of this inYention exhibits physical properties characteristic of thermoplastic elastomers, such as the well known commercial block copolymers based on styrene and diolefins or complex blends of polypropylene with elastomeric copolymers of ethylene and propylene.
Z0 The elastomeric polybutylene o~ this invention is a total product of the homopolymeri~ation of butene-l, characterized by ~he following properties:
Solubility in refluxing diethyl ether, % wt ~ 10 Crystallinity, by X-ray diffraction (Form I3, % 25-40 Mn x 10-3 (a) 20-300 Mw x 10-3 (a) 150-2,200 Mw/Mn 4~~
Melting Point(b), Form I, C ~ lOQ-118 Melting Point(C), Form ~I, C ~ 98~110 Tensile Strength At yield, psi 40n-1700 At break, psi 3000-45Qo Elongation at break, % 300-6Q0 3~
~lardness, Shore A, 10 seconds 50-90 In fractional crystallization method A, described below, the resi~ue of ~he third recrystallization represents no more than about 25% of the total polymer.
(a) By gel permeation chromatography.
~b) By differential scanning calorimeter (DSC) at heating rate of 20C/minute, using compression molded plaque, crystallized at 7C; after transformation to Form I.
(c) By DSC after crystallizing the melt at 10C/minute cooling rate and then immediately heating a~ 20C/minute.
In the preferred products of this invention, the total unextracted reaction product contains no more than 8%, and still more preferably no more than 5% of ether soluble components. The total polymerization products may be used without extraction or aFter extraction of all or a portion of the small ether soluble fraction, which owes its solubility to a combination of low steric regularity and low molecular weight.
Products of this invention having ether solubles contents close to the upper permissible llmit may exhibit some degree of surface adhesion or stickiness. For so~e uses, e.g., as film or sheet, this may make it desirable to extract some or all of the ether so'luble portion. For other uses, e.g., for blending with other polymers, the presence of a small ether-soluble component may not be objectionable. Products having ether solubles content in the preferred lower ranges do not exhibit significant surface adhesion or stickiness even though they contain a large proportion of polymer soluble in boiling n-heptane, whereas polybutylenes produced with a relatively non-stereoregulating conventional coordination catalyst, which also exhibit relatively low crystallinity and are also relatiYely flexible compared to conventional polybutylene, exhibit high surface adhesion, resulting from a large fraction of low steric regularity.
A prominent feature of our elastomeric polybutylene is its substantially suppressed level of crystallinity compared to conventional polybutylenes. A companion ~eature of our elastomeric polybutylene, one which makes it unique among the large number of polyolefins produced with s~ereose'lective catalysts, is the fact ~hat this suppression of ~z~
crystallinity is achieved without the corresponding large increase in amount of easily extractable polymer (soluble in refluxing ethyl e-ther) which results when the crystallinity enhancing features o~ a conYentional Ziegler-Natta polymeri~ation system are removed or reduced. This is shown by the dramatically di~ferent correlation between extractable polymer concentration and tensile strength shown by our elastomeric polybutylene compared to conventional polybutylene as illustrated in Figure 3. The origin of this unique relationship appears to lie in the co-enchainment of the isotactic sequences and sequences of frequent, mostly alternating (syndiotactic), tactic inversions of elastomeric polybutylene. On the other hand, stereoirregular species in conventional polybutylene largely coexist as separate fractions which are easily separable by extraction with ether.
Another distinguishing feature of our elastomeric polybutylene is its 13C NMR spectrum. The 13C NMR method provides detailed in-formation about the con-Figuration and conformation of short sections of polymer chains. A comparison o~ 13C NMR spectra of conventional polybutylenes with those of the products of this in~ention indicates a significant di~ference between the products, even though they both have a very high degree of steric order. The dif-ference shows up as a higher proportion of polymer comprised of short sequences of Frequent tactic inYersion alternating with 10nger isotactic seq~ences. This indicates for the products of this invention a s~ructure o-F short average isotactic sequences, which contrasts strikingly with the long average isotactic sequences of conventional polybutylene.
The enchained tactic defect structure which alternates in a stereoblock structure with isotactic sequences in elastomeric polybutene-l is responsible ~or 'che fine s~ructure associated ~ith the ~najor 13C NM~
absorptions o~ polybutene-l. As evident in Figure l and lB, this fine structure is much more prominent in the spectrum oF elastomeric polybutene-l than it is in conventional polybutylene ~lA~. Integrated intensities o~ the absorbances in the 26 to ~8 ppm region show 15% tactic defect structure associated wikh very short tactic inversion sequences (~ 5 Inonomer uni~s) g ~323~
and 9% alternating (syndiotactic) tactic inversions in sequences ~ S
monomer units. By comparison, typical conventional polybutylene has only 6% defect structure and 2% alternating or sydiotactic sequence stereo-structure. It is the larger amount of the net defect structure, enchained in not readily extractable molecules, that accounts for the elastomeric character of our new form of polybutylene.
13C NMR spectra of the fractionated polybutenes were recorded on a Bruker WM-360 spectrometer operating at 90.50 MHz under proton decoupling in FT mode. Instrument conditions were: 90 pulse of 50 ~s, 9 s repetition rate, 14 KHz sweep width and 32 K FID. The numbers of transients accumulated were 1500 to 3000. Solutions of polymers were rnade up in 15mm tubes with 0.5 to 1.0 9 per 5 cm3 of 2,2,4-~richlorobenzene with N2 degassing. Temperature for measurement was 130C. The chemical shift was presented in ppm down field from TMS as an external standard.
Like all products of olefin polymerizations with coordination catalysts, the products of this invention are mixtures of molecules differing from each other to some extent in structure and in molecular weight. The compositions and structures of such products are to some extent a function of the specific catalyst composi~ions and reactions conditions employed in their production.
The elastomeric polybutylene of this invention may be produced having a wide range of molecular weights. ~umber average molecular weights (Mn) may be from 20,000 to 300~000 and weigh~ average molecular weights (Mw) from 150,000 to 2,200,000. A characteristic of the products of this invention is a narrow molecular weight distribution, as indicated by ~he ra~io of ~iW/Mn (Q-value) which is typically of the order of 70 to 75%w or less of the Q~value of conven~ional polybutylene.
Both conventional and elastomeric isotactic polybutylene are unique compared to other commercial polyolefins in that they are capable of existing in seYeral crystalline modificatlons which can be isolated in almost pure forrn. Conventional isotactic polybutylene typically first solidifies from the mel~ in the crystal form known as Type II. Type II
is unstable with respect to Type I and converts to T~pe I at a rate ~23~
depending on a variety of factors, such as molecular weight~ tacticity, temperature, pressure, and mechanical shock Properties of the seYeral crys~al forms oF conventional isotactic polybutylene are well known.
The transformation of Type II to Type I has a marked effect on the physical properties. Density, rigidity and strength are increased.
Like conventional polybutylene, our elastomeric polybutylene crystallizes from the melt in the form of crystal Type II, which transforms to crystal Type I over a period of hours or days, depending on environmental conditions.
Physical properties of elastomeric polybutylene of this invention, crystallized in Type I form, are shown in Table 1. Also shown in Table ls for comparison, are corresponding properties of a butene-l homopolymer produced on a commercial scale in a solution process.
Table 1 Conventional PBElastom ric PB
Range Range Typical Solubility in refluxing diethyl ether, % ~t. 0.~-2.5 ~ 10 1.5-8 Crystallinity~ % 50-60 25-40 30-35 ~n x 10- 25-95 20-300 50-200 Mw x 10-3 ~230-1540 150-2200 500-1500 Mw/Mn 10-12 4-8 6-7 Melting Point~ Form I, C 123~126 ~100-118 ~106-116 Melting Point~ Form II, C 113-117 ~38-110 ~100-107 Tensile Properties Tensile strength at yield, psi2200-2600 400-1700 Tensile strength at break, psi~500-5500 3000 4500 Elongation at break 200-375 300-600 Hardness, Shore A, 10 sec. 50-90 75-87 The elastomeric character of polybutylene of this invention is demonstrated in Figure 2 of the drawing, which shows damping curves of a typ;cal plasticized PVC, of vulcanized natural rubber, and of a typical elastomeric polybutylene. Damping curves were determined by a free 3~
vibration torsion pendulum. Since the damping effect varies with the softness of the product it is accepted practice to recalculate damping curves for a product of uniform Shore Hardness. The curves in Figure 1 are normalized for product of 75 Shore Hardness, Method A (1 second).
The ordinate is amplitude and the abscissa is time in centiseconds.
The elastomeric polybutylene is shown to be more elastomeric than plasticized PVC, but less so than natural rubber.
Figure 3 is a plot of tensile yield strength in pounds per square inch Yersus ether solubles content in percent by weight, it illustrates the difference between the elastomeric polybutylene of this invention and conventional polybutylene.
Area A represents a range of values measured on elastomeric polybutylene of this invention. Line I represents an average curve for these values. Line II represents average values of conventional poly-butylenes.
Figure 4 illustrates how polybutylene of this invention differs uniquely from conventional elastomers in exhibiting a greatly superior surface hardness at a given flexibility. It is a plot of hardness versus Young's modulus. Hardness is plotted as Shore Hardness, Method A, 10 seconds. Curve I is an average curve representative o-f commercial PYC9 containing varying amounts of plasticizer ~o achieve varying degrees of flexibility. Area A represents a range of values for uncompounded elastomeric polybutylene of ~his invention. Curve II is an average curve of ~alues obtained with different compounded elastomers, both vulcanized SBR and thermoplastic block copolymersg which are identified on the drawing.
While uncompounded polybutylene of this invention has certain properties which are close to those of compounded PVC, as shown in Figure 4~ it also has uniquely advantageous properties compared to PVC.
This is illustrated ;n Fi~ure 5.
Fi~ure 5 relates to stress relaxation. Curve ~ is measured on a polybutylene according to this invention and curYes II, II' and II" on samples of commercial PYC con~aining different amounts of plasticizer 3~
and having nominal hardness ~alues of 40, 65 and 95, respectiYely. The stress relaxation test is conducted by stretching a specimen to 300% of elongation and observing the decrease ;n stress as a function of time.
In Figure 5, the abscissa is a logarithmic scale of time in seconds and -the ordinate is the percent of the initial stress at a ~iven time.
It is seen that elastomeric polybutylene of this invention has a relatively low rate of stress relaxation. This property is particularly desirable in products to be used for seals, gaskets and the like.
Table 2 provides a comparison of representatiYe properties of a sample o~ uncompounded elastomeric polybutylene of this invention with typical commercial PVC and elastomers. The elastomeric polybutylene was prepared as in Example 6.
Table 2 Uncompounded S-EB-SC) Thermoplastic Elastomeric ) b)ThermoplasticPolyurethane Poly~butylene PVCa EPDM Elastomer Elastomer ~ .
Tensile strength, at break, psi4000 1800 2000 6000 7000 Elongation at break, % 600 300 600 600 500 Tensile set at break, % 125 300 200 50 40 Hardness Shore A, 10 sec. 83 65 75 80 80 Young's Modulus, psi 6500 3000 4500 500Q 600 Stress recovery, %80 25 35 70 50 Hys~eresis loss, %60 60 70 45 55 Tear resistance~
30lbs/linear inch1100 6Q0 450 500 700 Resilience, % 75 35 45 80 70 Processing temperature, F 350 350 450 500 500 . .
(a) PVC plasticized with about 40% wt dioctyl phthalate (b~ Mineral filled, vulcanized (c) Uncompounded (d~ Pol~yether based ';
39~
The unique composition of elastomeric polybutylene of this invention, Gontrasted with conventional polybutylene which has been prepared at conditions leading to lower average isotacticity is demonstrated by fractional crystallization of the whole polymer from n-heptane. The method is regarded as representing a fractionation with respect to crystal-lizabilîty of the polymer, which in turn is believed to be determ-ined by the distribution of isotactic sequences and tactic inversions in the polymer molecules. The procedure, referred to herein as fractional crystallization Method A~ is carried out as follows:
100 grams of the total polymer is dissolved in 1 liter of n-heptane at 50-60C. The solution is cooled to ambient temperature of about 25C and allowed to stand ~or at least 24 hours, to permit complete precipitation of the polymer portion which is crystallizable at those conditions. The solid fraction is filtered oif, washed with 1 liter of n-heptane, dried and weighed. The soluble -Fraction is recovered from ~he combined filtrate and wash liquid by evaporation o~ the solvent and weighed. The procedure is repeated with the total ~irst precipitate and repeated twice more with the successive precipitates, using the same amount of n-heptane and the same conditions.
It has been found that in fractional precipitation of a typical polybutylene oF this invention by this method, the percent by weight of the total polymer which remains dissolved in each stage is of the order of 25% o~ the total polymer. ~y contrast9 when the same procedure was carried out on a conventional polybutylene which had been prepared with poorly stereoselective catalysts, and which had an et'ner extractable content of ~2.2%, the amount of polymer which rema-ined in the first filtrate was abo~t 27%wt. but decreased to abo~t 16%wt. and ~ 4%~t. in the second and third filtrates, leaving more than 50%~tO as residue of the th;rd recrystallization. These results are graphically illus~rated in Figure 6, which is a plot of cumulative amounts dissolved Yersus number of recrystallization steps.
Crystallization method ~, carried out on conventional polybutylene, showed less khan 4% soluble in ~he first recyrskalli~ation and essentially none in the later recrystallizations.
~3~3~
There are various theories with respect to the mechanism of polymeriza-tion over Ziegler-Natta catalysts. A widely held view is that the selectivity of Ziegler-Natta catalysts in alpha-olefin poly-merization is simply a ~unction of the relative populations of selective (isotactic) and non-selective (atactic) sites on the procatalyst.
Accordingly, the isotacticity of a given unextracted polymer i5 considered to be determined by the relative proportions it contains o~ highly isotactic product polymerized at selective sites on the procatalyst and highly heterotactic ~atactic) product polymerized at non-selective sites. The heterotactic fraction is non-crystallizable or only very slightly crystallizable and can be separated from the isotactic portion of the whole polymer by solvent extraction, e.g., in boiling n-heptane, as typically employed for polypropylene, or in boiling diethyl ether~
typically employed for polybutylene. The amount of extractable polymer is the most commonly used indication of the select1vity of the ca~alyst and the isotactic purity of the polymer. Selectivity control agents which are employed in many commercial Ziegler-Natta systems to control isotacticity and hence crystallinity are regarded as preferentially deactivating non-selective catalyst sites.
We now believe that there is an additional dimension of stereo-selectivity. This additional dimension has to do with the ability of some cata~lyst sites to exist for shor~ durations in a mode ~hich produces alternatin~ tac~ic inversions in polymer molecules produced at otherwise jsotactic selective sites. The inversions or short sequences of mostly alternating inversions (syndiotactic sequences) interrupt runs of isotactic sequences~ producing isotactic blocks which are longer or shorter, depending upon the ~requency or rate of inversion in relation to the rate of polymeri~ation propagation at the particular active catalyst site. The isotactic stereoblocks will be long for catalysts where population of such dual mode sites is small and/or where the ratio kiSotactic!kinyersion is large, and/or where the time spent by a dual mode si~e in the inversion or syndiotactic mode is small Such is the predominant situation in conventional Ziegler-Natta catalysis; the stereoblocks w-ill be shorter for catalyst where these situations are reYersed.
We have discovered that under certain operating conditions supported coordination catalyst systems appear to fall in the latter category in the polymerization of butene-l, as indicated by 13C NMR
analysis of the polymer products. Thus, the steric purity of polybutylene produced in such polymerizations appears to be not just a function o~
the relative proportions of isotactic and atactic catalyst sites but also a sensitiYe ~unction of what appears to be highly specific chemistry leadin~ to tactic inversions at isotactic sites.
Natta et al described certain stereoisomer block copolymers jn lJ.S. Patent 3,175,999 as polymers in which isotactic sections alternate with atactic sections. The stereoisomer block copolymers were produced, as illustrated in the examples, with catalysts which have poor ability to produce isotactic polymers, and represented only small proportions of the total polymer product. In contrast to this, our elastomeric polybutylene can be produced as the total polymerization product by means of catalysts which are capable o~ being highly stereodirecting for the production of isotactic polymers. Our polymers may be produced by means of catalyst systems which, when employed in propylene polymeri~ation, produce highly crystalline isotactic polypropylene. Our elastomeric polybutylene consists mainly of isotactic blocks, interrupted by inversions oF only one or a few molecules largely in alternating (syndiotactic~ stereochemical configurationsO
The preferred catalyst to be employed for production of elastomeric polybutylene of this invention is one in which the solid component comprises a support o~ magnesium chloride in an active ~orm, combined with an electron donor and titanium halide; typically the componen~s are MgC12, TiC14 and an aromatlc ester~ e.g., ethyl benzoate or p-ethyl toluate. This solid component is combined with an alumlnum alkyl, typically a trialkylaluminum such as triethyl aluminum and a selectiYity control agent, typically ethyl anisate. Numerous Yariants o~ these catalysts are described in recent patents7 such as U.S. Pa~ents Nos.
~ ~23~
4,051,313, 4,115,319, 4,235,9~ and 4,250,287. Preferred to da~e arecatalysts prepared as described in U.S. Patent ~,329,253 to Goodall et al and in European Patent Application 19,330, published November 26, 1 9~0.
The conditions under which the polymerization is conducted, including the method of combining the catalyst components, can also affect the type of polymer produced. In a preferred method, all three catalyst components are pre-mixed before being introduced into the polymerization zone, and the procatalyst and cocatalyst are combined before the electron danor is combined with the catalyst mixture.
The polymerization is preferably conducted as a solution poly-merization process, using butene-l as the reaction medium. However, it may be conducted in liquid butene-l at conditions under which the polymer is produced as a solid in a so-called slurry polymerization. The poly-merization may be carried out in batch or continuous modes.
Suitable ratios of the several catalyst components are as follows-Ti content o^f procatalyst, ~wt. 1 - 5 Al:Ti atomic ratio ~ 50-150; preferably about 65-100 SCA:Ti molar ratio > 4.5-20, preferably about ~.5-15 Al:SCA molar ratio 5:1-15:1 H2:Ti molar ratio 0-2500 The interaction of procatalyst, cocatalyst~ selectivity control agent and hydrogen in the production of iso~actic polymers is basically the same in the production of elastomeric polybutylene as it is in the production of other isotactic polyolefins. However, i~ has been observed that the molar ratio of cocatalyst to ~itaniumS when using appropriate amounts of SCA, is preferably not above 100 and should not exceed ahout 150. At ratîos approaching and exceeding 150, the polymer product gradually becomes less elastomeric and more nearly like conventional polybutylene.
The catalysts employed in the production of elastomeric poly-butylene may be of sufficiently hi~h activity that no product deashing step is required. If catalyst residues are to be deactivated and removed, this may be accomplished by conventional means employed in cleanup of olefin polymers produced over such catalysts, e.g., by contact with an alcohol, followed by extraction with water.
The elastomeric polybutylene of this invention, which combines the chemical properties of polybutylene with physical characteristics resembling those oF plasticized PVC and of thermoplastic elastomers, is expected to find many uses.
Unblended products of this invention are relatively homogeneous materials of excellent chemical resistance as well as physical toughness.
Polybutylene of this invention has been converted into films, including heavy gauge film use~ul for bagging of industrial powdered goods. It is also useful for conversion into stretchable plastic -Fibers and filaments.
For applications in which thermoplastic elastomers have hereto-before been employed, the products of this invention can be compounded and processed similarly to conventional hydrocarbon elastomers, e.g., by blending with other polymers such as polypropylene7 with extenders such as mineral oils and waxes, and with fillers such as calcium carbona~e, for use as molded or extruded products in various applications for which
2~ hydrocarbon elastomers are conventionally employed.
The butene-l polymers of this invention are also useful for those uses where flexible vinyl polymers, such as highly plasticized poly(vinylchloride) (P~C), have heretofore been employed, including conversion into sheets and tubing for a variety of uses. UnlikP P~C, they do not require the use of plasticizers to achieve and retain the des;red ~lexibility. They do not have the disadvantages of potential health and safety problems associated with vinyl chloride monomer, with burning of P~C and with PVC plasticizers.
The butene-l polymers of this invention share th~ chemical properties of conven-tional isotactic polybutylene. Additi~es relying on chemical action, such as stabilizers again~t deterioration due to heat or light, can be expected to have the same effectiveness in the polybutylene 1~
~ ~23~
of this ;nvention as in conventional polybutylene. The elastomeric poly-butylene may also be mod;fied by addition of fillers or pigments.
Mechanical properties reported in Table 2 and in the following examples were determined on compression molded specimens.
For the data in Table 2 and in Figures 2-5, the specimens were about 25 mil thick, prepared by compression molding at 177C and aged 7 days at room temperature for conversion to crystal form I.
For the data in the following examples, specimens were prepared by compression molding at 177-204C and subjected to accelerated aging at room temperature for 10 minutes under 207 MPa (megaPascals) hydro-static pressure ~or conversion to crystal form I.
For determination of ether extractables, a 2.5 gram film specimen or a similar amount of polymer crumb or extruded pellets is extracted in a Soxhlet extraction apparatus with 100 ml refluxing diethyl ether for 3 hours.
Melt index is determined according to ASTM method D-1238, Procedure A.
Tensile properties reported in the Examples are dekermined according to ASTM nnethod D-638 on specimen about 0.10 inch thick and 0.24 inch wide. Tensile properties reported in Table 2 and in Figure 3 are determined according ~o ASTM method D-412.
Other properties are determined by the following standard methods or variations thereof:
ASTM No.
Hardness, Shore A, 10 seconds D-678 Tear resistance D 624 Resilience D-94 a) using free Yibration torsion pendulunl.
The plot of stresS ~. strain of elastomers7 including our elastomeric polybutylene, does not show the decrea$e of stress which defines the yield point for true thermoplastic resins. Rather, the curve shows a rise at an ~nltial slope, a continued rise at a lesser Z3~S~
slope, and a final rise to the break point, which may again be at an increased slope. The slope of the initial rise, expressed as psi, is Young's modulus. The slope of the next7 more gradually rising part oF
the curve, is referred to as modulus of chain extension. The point at which these two slope lines intersect is taken as defining the yield stress.
The following examples illustrate the invention, but are not to be considered as limiting it.
EXAMPLES
Pol~merization Method Unless other~ise statedg polymerizations were carried out as follows:
2000 ml of carefully dried butene-l (99.5% wt pure~ ~as charged to a dry l-gallon autoclave reactor, equipped with a turbine type agitator.
A predetermined amount of hydrogen was charged to the reactor from a calibrated pressure vessel. The reactor was heated to about 60C. With the agitator operating at 1000 rpm, a freshly prepared slurry of all three catalyst components was injected; the temperature of the agitated reaction mixture was held at about 66C by heating or cooling, as required. Reactions were typically run for 1 hour, resulting in a solution of about 20% of polymer in butene-l. At the end of the run, the reactor contents were transferred to a 15 liter vessel containing water. This killed-the polymerization reaction, flashed off unreacted monomer, precipita~ed the polymer as solid crumbs9 and transferred catalyst residue into the water phase. The solid polymer was recovered, chopped, inhibited with 0.1% wt of 2,6-di-tert butyl-4-methyl phenol and dried in a vacuum oven.
EXAMPL.ES 1-5; COMPARATIVE EXAMPLES 1-3 Table 3 lists the results of a number of polymerizations conducted as described above. The procatalysts (solid catqlyst com-ponents) employed are designated as Follows:
Procata~st _ A TiC14-McJCI2-Ethyl ben~oate (EB) composite
The butene-l polymers of this invention are also useful for those uses where flexible vinyl polymers, such as highly plasticized poly(vinylchloride) (P~C), have heretofore been employed, including conversion into sheets and tubing for a variety of uses. UnlikP P~C, they do not require the use of plasticizers to achieve and retain the des;red ~lexibility. They do not have the disadvantages of potential health and safety problems associated with vinyl chloride monomer, with burning of P~C and with PVC plasticizers.
The butene-l polymers of this invention share th~ chemical properties of conven-tional isotactic polybutylene. Additi~es relying on chemical action, such as stabilizers again~t deterioration due to heat or light, can be expected to have the same effectiveness in the polybutylene 1~
~ ~23~
of this ;nvention as in conventional polybutylene. The elastomeric poly-butylene may also be mod;fied by addition of fillers or pigments.
Mechanical properties reported in Table 2 and in the following examples were determined on compression molded specimens.
For the data in Table 2 and in Figures 2-5, the specimens were about 25 mil thick, prepared by compression molding at 177C and aged 7 days at room temperature for conversion to crystal form I.
For the data in the following examples, specimens were prepared by compression molding at 177-204C and subjected to accelerated aging at room temperature for 10 minutes under 207 MPa (megaPascals) hydro-static pressure ~or conversion to crystal form I.
For determination of ether extractables, a 2.5 gram film specimen or a similar amount of polymer crumb or extruded pellets is extracted in a Soxhlet extraction apparatus with 100 ml refluxing diethyl ether for 3 hours.
Melt index is determined according to ASTM method D-1238, Procedure A.
Tensile properties reported in the Examples are dekermined according to ASTM nnethod D-638 on specimen about 0.10 inch thick and 0.24 inch wide. Tensile properties reported in Table 2 and in Figure 3 are determined according ~o ASTM method D-412.
Other properties are determined by the following standard methods or variations thereof:
ASTM No.
Hardness, Shore A, 10 seconds D-678 Tear resistance D 624 Resilience D-94 a) using free Yibration torsion pendulunl.
The plot of stresS ~. strain of elastomers7 including our elastomeric polybutylene, does not show the decrea$e of stress which defines the yield point for true thermoplastic resins. Rather, the curve shows a rise at an ~nltial slope, a continued rise at a lesser Z3~S~
slope, and a final rise to the break point, which may again be at an increased slope. The slope of the initial rise, expressed as psi, is Young's modulus. The slope of the next7 more gradually rising part oF
the curve, is referred to as modulus of chain extension. The point at which these two slope lines intersect is taken as defining the yield stress.
The following examples illustrate the invention, but are not to be considered as limiting it.
EXAMPLES
Pol~merization Method Unless other~ise statedg polymerizations were carried out as follows:
2000 ml of carefully dried butene-l (99.5% wt pure~ ~as charged to a dry l-gallon autoclave reactor, equipped with a turbine type agitator.
A predetermined amount of hydrogen was charged to the reactor from a calibrated pressure vessel. The reactor was heated to about 60C. With the agitator operating at 1000 rpm, a freshly prepared slurry of all three catalyst components was injected; the temperature of the agitated reaction mixture was held at about 66C by heating or cooling, as required. Reactions were typically run for 1 hour, resulting in a solution of about 20% of polymer in butene-l. At the end of the run, the reactor contents were transferred to a 15 liter vessel containing water. This killed-the polymerization reaction, flashed off unreacted monomer, precipita~ed the polymer as solid crumbs9 and transferred catalyst residue into the water phase. The solid polymer was recovered, chopped, inhibited with 0.1% wt of 2,6-di-tert butyl-4-methyl phenol and dried in a vacuum oven.
EXAMPL.ES 1-5; COMPARATIVE EXAMPLES 1-3 Table 3 lists the results of a number of polymerizations conducted as described above. The procatalysts (solid catqlyst com-ponents) employed are designated as Follows:
Procata~st _ A TiC14-McJCI2-Ethyl ben~oate (EB) composite
3~
B TiC13.1/3 AlC13 = commercial product Stauffer catalyst AA
~ n the examples of the invention shown in Table 3, the pro-catalyst was combined with the other components as a suspension in n-heptane, containing 0.0~ mmol Ti/per ml. The cocatalyst was triethyl aluminum ~TEA) employed as a 25%wt solution in n-heptane. The electron donor was p-ethyl anisate (PEA3, employed as the neat liquid.
The amo~nts of the seYeral catalyst components employed in each example are shown in Table 3.
10In the examples of the lnvention shown in Table 3, the catalyst components were combined in a serum vial in a dry box, and injected into the reactor. Unless otherwise stated, the -time elapsed while the components were combined and injected into the reactor was no more than three minutes.
The catalyst components were comblned as follows:
In Example 1, PEA was added to TEA at room temperature and allowed to react for 10 minutes. This mixture and the procatalyst were separately injected into the reactor.
In Examples 2-5 and comparative Example 1, all three catalyst components were combined in a serum vial and the total catalyst mixture injected into the reactor.
The order of combina~ion o~ the catalyst components was as ~ollows:
Example 2: TEA added to procatalysti PEA added to the mixture.
Example 3: TEA added to procatalysti mixture held for 30 minutes at room temperature;
PEA added to the mixture.
Example 4: Procatalyst added to TEA, 30mixture added to PEA.
Example 5: TEA added to procatal~st;
pEA added to mixture.
323~
The method of Example ~ is preferred for production of SSPB.
The method of Examples 2 and 5 is also satisfactory.
In Comparative Example 1, the order of addition was: TEA
added to PEA; mixture added to procatalyst. This resulted in a total polymer having an excessively high content of ether soluble polymer.
Cor~parative Example 2 in Table 3 shows physical properties of a commercial butene-l polymer, produced with a commercial TiC13 type Ziegler/Natta catalyst.
Comparative Example 3 in Table 3 was carried out in laboratory equipment of the same mode as that in Examples 1-5, but using a commercial TiC13 procatalyst.
Additional illustrative examples were carried out in a 15 liter autoclave.
The catalys~ components were used as described above, that is~
the procatalyst was used as 0.03 mmol Ti per liter suspension in n-heptane5 T~A as 25%wt solution in n-heptane~ and PEA added next. The procedure was essentially as described above, except that larger amounts were employed. The autoclave contained about 22.7 kg o-F carefully dried 20 butene-l~ 211 mmoles oF hydrogen was added. The catalyst mixture was prepared by adding the procatalyst to the TEA and adding the resulting suspension to the PEA in 5 ml n-heptane. The total catalyst mixture was injected into the butene-l in the autoclave, which was at 60QC and hPld at that temperature, with agitation, for one hour.
Product recovery was as described above.
Reagent proportions and product properties are shown in Table ~.
3~
V)O d-~D 00 NO LO O O
LLI ~I'_L(~ ~) Or-- d- N C~l ~_ O
L~~
OLIJ
C~ C~:
~ ~ OO ON OO OO
LLI I~S ~N ~t ~:: L a.l N~) ~Y) t~ ~r) N L~
::_ l_ ~
Il~ ~
C~ r-~r- O O Oa:) o ~ o o aJ ~ ~ N ~ CO ~Y) 00~r) 00 l:L ~ C~ CO O ~U:~ N N
~: ~ ai E ~D N ~D ~ ~ e~ ~
o ~ ~ E o .-- N NO ~ O O
l_ a.~
r-- ~ CO ~N a~ COCO O
S ~ ~5!Lf) ~~ d~
LLJ ~o> ,_ v~ ~ a~
. E ~
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(~s V C~ ~~) ~~ r-- L~
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~ V~
~ O
TN ~ E L() Lf LL > L L~'~ ON
O~ ~n c~l ~~ N~
C ~ O ~
L~E E oo oo oo C~
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~ >, V ~ o a~ ~ ~Cl CC ~C ~ I r~
~` L~ JLLI LLI LLI IIJ I O
LLII_ C~_ ~. C~.. Q C~ ~L o ~ U~ t-~- OO OO OOLt') O a1 E b NN NN NN CO N a.J
~ CC
v a O L~ LlJ LLI L~l >~
I_ ~ ) O
.- 1~ Q
Oo oo oo c~
O . .. . . . .
+~ ~ OOOOOO O
~ ~ V~
r8 t-J
~ ~ ~ r~ I~ I~ ~ N 1~ V
oV 3 CO CO CO 00 LO CO --~
1:~O ~ NC~l NN ~N O
~ >~
Q c~
1~ ~_ .~
~ al C~) c r- N ~r) O
E ~ n. ~:L rL ~
X E ,_ N~ d-L~ E ~_ LIJ Z O O O
23~L~
C_ ., LL~ ~ O O O O
H ~) ~æ r~
I__ C ~ ~
O
LL~
~ CO~ ~
LL~ (~ O OO O
LLJ (L) I~CO C~
~_ CO C~J ~ ~ C~J
~ ~lJ
O ~ ~., O O O O
Il) V~ .-- cn~ Is') _ R 0~ ~ ~ ~
C~ ~ O~ ~ I~t~J
a~ I~ ~C~l ~ aJ V o o ,_,_ o O ~ ~ ~,_ ~n ~ 2 Ln ~D 1~ CO
a~
~ ~--~ a~
VO~
.
u) ~ a) 0 ,_ ~ ~ o o o oo r8 _ ~ c_ ~ O Lf~ C~ O
O~s ~ ~ r~ ~
(~ ~ C~l ~d- `
~ cn~ o C~J ~ ~ r- ~ ~C`J
I ~ C~J ~C`J c--~ ~ V~ L~
o c_ ~
O o ~ ~ In ~
C~ ~ ~
o ~ ct CC 'C '~:
~ ~ LLI L~
Ll~ ~ ~ C~
~ V~
I, ~ _ a~
V~ ~ o o o o 0 ~
o a~
L~
._ ~ n5 E
~ ~ C~
,-' .~
_ aJ N C~J C~l CO
S~ 3 O O O
O ~ ) ~ f~
"_ a~
I__ ~
,_ ~
~L
E E
x - 2~ -23~
Elastomeric polybutylene prepared as in Example 6 was converted by compression molding into a film of approximately 0.535 mm thickness.
The film had the following properties:
Melt index 1-0 Tensile strength at break, psi 3970 Elongation~ % 550 Young's modulus 6200 Shore hardness A, 10 sec. 83 Trouser tear, lbs/linear inch 1140 Hysteresis loss, % 59
B TiC13.1/3 AlC13 = commercial product Stauffer catalyst AA
~ n the examples of the invention shown in Table 3, the pro-catalyst was combined with the other components as a suspension in n-heptane, containing 0.0~ mmol Ti/per ml. The cocatalyst was triethyl aluminum ~TEA) employed as a 25%wt solution in n-heptane. The electron donor was p-ethyl anisate (PEA3, employed as the neat liquid.
The amo~nts of the seYeral catalyst components employed in each example are shown in Table 3.
10In the examples of the lnvention shown in Table 3, the catalyst components were combined in a serum vial in a dry box, and injected into the reactor. Unless otherwise stated, the -time elapsed while the components were combined and injected into the reactor was no more than three minutes.
The catalyst components were comblned as follows:
In Example 1, PEA was added to TEA at room temperature and allowed to react for 10 minutes. This mixture and the procatalyst were separately injected into the reactor.
In Examples 2-5 and comparative Example 1, all three catalyst components were combined in a serum vial and the total catalyst mixture injected into the reactor.
The order of combina~ion o~ the catalyst components was as ~ollows:
Example 2: TEA added to procatalysti PEA added to the mixture.
Example 3: TEA added to procatalysti mixture held for 30 minutes at room temperature;
PEA added to the mixture.
Example 4: Procatalyst added to TEA, 30mixture added to PEA.
Example 5: TEA added to procatal~st;
pEA added to mixture.
323~
The method of Example ~ is preferred for production of SSPB.
The method of Examples 2 and 5 is also satisfactory.
In Comparative Example 1, the order of addition was: TEA
added to PEA; mixture added to procatalyst. This resulted in a total polymer having an excessively high content of ether soluble polymer.
Cor~parative Example 2 in Table 3 shows physical properties of a commercial butene-l polymer, produced with a commercial TiC13 type Ziegler/Natta catalyst.
Comparative Example 3 in Table 3 was carried out in laboratory equipment of the same mode as that in Examples 1-5, but using a commercial TiC13 procatalyst.
Additional illustrative examples were carried out in a 15 liter autoclave.
The catalys~ components were used as described above, that is~
the procatalyst was used as 0.03 mmol Ti per liter suspension in n-heptane5 T~A as 25%wt solution in n-heptane~ and PEA added next. The procedure was essentially as described above, except that larger amounts were employed. The autoclave contained about 22.7 kg o-F carefully dried 20 butene-l~ 211 mmoles oF hydrogen was added. The catalyst mixture was prepared by adding the procatalyst to the TEA and adding the resulting suspension to the PEA in 5 ml n-heptane. The total catalyst mixture was injected into the butene-l in the autoclave, which was at 60QC and hPld at that temperature, with agitation, for one hour.
Product recovery was as described above.
Reagent proportions and product properties are shown in Table ~.
3~
V)O d-~D 00 NO LO O O
LLI ~I'_L(~ ~) Or-- d- N C~l ~_ O
L~~
OLIJ
C~ C~:
~ ~ OO ON OO OO
LLI I~S ~N ~t ~:: L a.l N~) ~Y) t~ ~r) N L~
::_ l_ ~
Il~ ~
C~ r-~r- O O Oa:) o ~ o o aJ ~ ~ N ~ CO ~Y) 00~r) 00 l:L ~ C~ CO O ~U:~ N N
~: ~ ai E ~D N ~D ~ ~ e~ ~
o ~ ~ E o .-- N NO ~ O O
l_ a.~
r-- ~ CO ~N a~ COCO O
S ~ ~5!Lf) ~~ d~
LLJ ~o> ,_ v~ ~ a~
. E ~
~- :. ::-, O O Od- ~LO ~J IS ) ~ , O C~ ~ g ~O
(~s V C~ ~~) ~~ r-- L~
~CIC C~l ~
~ V~
~ O
TN ~ E L() Lf LL > L L~'~ ON
O~ ~n c~l ~~ N~
C ~ O ~
L~E E oo oo oo C~
~_ a o F
~ >, V ~ o a~ ~ ~Cl CC ~C ~ I r~
~` L~ JLLI LLI LLI IIJ I O
LLII_ C~_ ~. C~.. Q C~ ~L o ~ U~ t-~- OO OO OOLt') O a1 E b NN NN NN CO N a.J
~ CC
v a O L~ LlJ LLI L~l >~
I_ ~ ) O
.- 1~ Q
Oo oo oo c~
O . .. . . . .
+~ ~ OOOOOO O
~ ~ V~
r8 t-J
~ ~ ~ r~ I~ I~ ~ N 1~ V
oV 3 CO CO CO 00 LO CO --~
1:~O ~ NC~l NN ~N O
~ >~
Q c~
1~ ~_ .~
~ al C~) c r- N ~r) O
E ~ n. ~:L rL ~
X E ,_ N~ d-L~ E ~_ LIJ Z O O O
23~L~
C_ ., LL~ ~ O O O O
H ~) ~æ r~
I__ C ~ ~
O
LL~
~ CO~ ~
LL~ (~ O OO O
LLJ (L) I~CO C~
~_ CO C~J ~ ~ C~J
~ ~lJ
O ~ ~., O O O O
Il) V~ .-- cn~ Is') _ R 0~ ~ ~ ~
C~ ~ O~ ~ I~t~J
a~ I~ ~C~l ~ aJ V o o ,_,_ o O ~ ~ ~,_ ~n ~ 2 Ln ~D 1~ CO
a~
~ ~--~ a~
VO~
.
u) ~ a) 0 ,_ ~ ~ o o o oo r8 _ ~ c_ ~ O Lf~ C~ O
O~s ~ ~ r~ ~
(~ ~ C~l ~d- `
~ cn~ o C~J ~ ~ r- ~ ~C`J
I ~ C~J ~C`J c--~ ~ V~ L~
o c_ ~
O o ~ ~ In ~
C~ ~ ~
o ~ ct CC 'C '~:
~ ~ LLI L~
Ll~ ~ ~ C~
~ V~
I, ~ _ a~
V~ ~ o o o o 0 ~
o a~
L~
._ ~ n5 E
~ ~ C~
,-' .~
_ aJ N C~J C~l CO
S~ 3 O O O
O ~ ) ~ f~
"_ a~
I__ ~
,_ ~
~L
E E
x - 2~ -23~
Elastomeric polybutylene prepared as in Example 6 was converted by compression molding into a film of approximately 0.535 mm thickness.
The film had the following properties:
Melt index 1-0 Tensile strength at break, psi 3970 Elongation~ % 550 Young's modulus 6200 Shore hardness A, 10 sec. 83 Trouser tear, lbs/linear inch 1140 Hysteresis loss, % 59
Claims (2)
PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A total, unextracted and unfractionated product of the homopolymerization of l-butene over titanium halide coordination catalyst, characterized by the following properties:
2. A polymer according to claim 1 having no more than 5%
solubility in refluxing diethyl ether.
solubility in refluxing diethyl ether.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US36938882A | 1982-04-19 | 1982-04-19 | |
| US369,388 | 1982-04-19 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1192349A true CA1192349A (en) | 1985-08-20 |
Family
ID=23455277
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000422652A Expired CA1192349A (en) | 1982-04-19 | 1983-03-01 | Polybutylene |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1192349A (en) |
-
1983
- 1983-03-01 CA CA000422652A patent/CA1192349A/en not_active Expired
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