MXPA00002009A

MXPA00002009A - In-situ rheology modification of polyolefins

Info

Publication number: MXPA00002009A
Application number: MXPA/A/2000/002009A
Authority: MX
Inventors: H Cummins Clark; J Mullins Michael; Craig Silvis H; Robert L Sammler
Original assignee: Dow Global Technologies Inc
Priority date: 1997-08-27
Filing date: 2000-02-25
Publication date: 2001-05-17

Abstract

The present invention includes an improved process for the preparation of rheology modified polyolefins, either alone or as blends, that remain thermoplastic and melt processable and possess improved melt strength by (a) heating a substantially uniform admixture of a polyolefin and a rheology modifying amount of a poly(sulfonyl azide) in the same vessel. The process of the invention is particularly applicable to polyolefins which comprise greater than 50 mole percent monomer having at least one tertiary hydrogen atom, preferabl propylene polymers.

Description

MODIFICATION OF POLYOLEPHIN RHEOLOGY ON THE SITE This invention relates to polyolefins, more particularly to the reaction of polyolefins with poly (sulfonyl azides) s. As used herein, the term "rheology modification" means the change in the resistance of the molten polymer to the flow. The resistance of the polymer melts to the flow is indicated by (1) the tensile stress growth coefficient, and (2) the dynamic tear viscosity coefficient. The tensile stress growth coefficient? E + is measured during the initiation of the uniaxial extensional flow by means within the capacity of the technique, such as are described by J. Meissner in Proc. Xllth International Congress on Rheology, Quebec, Canada, August 1996, pages 7-10, and by J. Meissner and J. Hostettler, Rheol. Acta, 33, 1-21 (1994). The dynamic tear viscosity coefficient is measured with low amplitude sinusoidal tear flow experiments by means within the capability of the art, such as are described by R. Hingmann and B.L. Marczinke, J. Rheoi. 38 (3), 573-87, 1994. The rheology of polyolefins is often modified using non-selective chemistries that involve free radicals generated, for example, using peroxides or high-energy radiation. Although these techniques are useful for polyethylene and some copolymers thereof, chemicals that involve the generation of free radicals at elevated temperatures tend to degrade the molecular weight of polypropylene and its copolymers, due to the high rate of chain separation reactions in the tertiary carbon atoms along the base structure of the polymer, whose separation often dominates the chain coupling, and leads to polymer chains of a lower molecular weight rather than higher molecular weight. The reaction of polypropylene with peroxides and pentaerythritol triacrylate, as reported by Wang et al., In Journal of Applied Polymer Science, volume 61, 1395-1404 (1996). They teach that the branching of isotactic polypropylene can be performed by grafting free radicals of di- and tri-vinyl compounds onto polypropylene. However, this approach does not work well in actual practice, since the higher rate of chain separation tends to dominate the limited amount of chain coupling that takes place. This occurs because chain separation is an intramolecular process that follows first-order kinetics, while branching is an intermolecular process with a kinetics that is minimally second-order. The chain separation results in a lower molecular weight and a higher melt flow rate than would be observed where the branching was not accompanied by separation. Because the separation is not uniform, the molecular weight distribution increases as lower molecular weight polymer chains referred to in the art as "tails" are formed. Another approach to achieve the branching taught in the patent literature involves electron beam irradiation of isotactic polypropylene at lower temperatures (for example, European Patent Number EP-0, 190,889, assigned to Himont Incorporated). This process is expensive, since a source of electron beam irradiation must be added to the polypropylene process equipment, the irradiation must be done on the solid phase in an inert atmosphere, and the macroradicals must be deactivated in the product before processing of fusion to avoid chain separation reactions. With the free radicals present, separation is expected. The technique includes different methods of reported free radicals for joining long chains to polymers such as polypropylene. For example, DeNicola et al. Report, in U.S. Patent No. 5,414,027, the use of high energy radiation (ionization) in a reduced oxygen atmosphere to form free radicals. Although the melting strength of the polymer is improved, DeNicola et al declare that the irradiation results in a chain separation, even when there is a recombination of the chain fragments to reform chains, as well as a union of the chain fragments with chains to form branches, and there may be a net reduction in the weight average molecular weight between the starting material and the final product. In general, the intrinsic viscosity of the starting material indicating the molecular weight should be from 1 to 25, preferably from 2 to 6, to result in a final product with an intrinsic viscosity of 0.8 to 25, preferably 1. a 3. Methods for altering the polymer structure and associated rheology of polyethylenes do not work well for polyolefins, which have tertiary hydrogens on their base structures. Most of the methods involve free radicals that dissociate the base structure of the polyolefins that have tertiary hydrogens, that is, hydrogen atoms bonded with carbon atoms, which in turn are bonded with three other carbon atoms, in such a way that When the hydrogen is abstracted, a tertiary free radical is formed, and therefore stable. Polypropylene, including copolymers of propylene with other alpha-olefins, is the preferred example of these polymers having tertiary hydrogen atoms. Polypropylene polymers are particularly susceptible to chain separation, due to the formation of tertiary radicals. Styrene polymers also stabilize free radicals, and therefore, are subject to chain separation. The mixture of polypropylene with other materials has also been used in an effort to improve its melt-resistance properties; however, due to differences in refractive indices, the products have poor optical properties, such as nebulosity and transmission. Accordingly, there is a need in a more selective way to modify the rheology of polypropylene, which does not lead to significant decreases in molecular weight, or which requires mixing, and therefore, decreased physical properties. The teachings of the Patents of the United States of North America Numbers US 3,058,944; 3,336,268; and 3,530,108, include the reaction of certain poly (sulfonyl azide) compounds with isotactic polypropylene or other polyolefins, by inserting nitrene into C-H bonds. The product reported in the United States Patent Number US 3,058,944 is cross-linked. The product reported in U.S. Patent No. 3,530,108 is foamed and cured with cycloalkanedi (sulfonylazide) of a given formula. In U.S. Patent Number 3,336,268, the resulting reaction products are referred to as "bridged polymers", because the polymer chains are "bridged" with sulfonamide bridges. The disclosed process includes a mixing step, such as grinding or mixing the sulfonilazide and the polymer in solution or dispersion, then a heating step where the temperature is sufficient to decompose the sulfonyl azide (from 100 ° C to 225 ° C). C, depending on the decomposition temperature of the azide). The starting polypropylene polymer for the claimed process has a molecular weight of at least 275,000. The blends taught in U.S. Patent No. 3,336,268 have up to 25 percent ethylene-propylene elastomer. "Bridged" products obtained from the process disclosed in US Pat. No. 3,336,268, exhibit less rheology modification than is desirably obtained, and tend to have at least a lower ductility, tensile strength to breakage, flexural modulus, Izod impact resistance, or MTS peak impact energy of what is desirable. Canadian Patent Number 797,917 discloses certain similarly bridged polyethylenes. Functionalized sulfonilazides, particularly the sulfonylazidosiloxanes, have been used as compatibilizers for mixtures and compounds, and function by grafting onto one of the components by means of the sulfonyl azide chemistry reported in US Pat. Nos. 3,616,199 (Breslow) , 4,452,855 (Brodsky et al.) And 3,706,592 (Thomson). An isotactic or syndiotactic polypropylene having sufficient rheology modification to avoid the degree of collapse seen in a corresponding unmodified polypropylene of the same tacticity, conveniently at temperatures useful in the thermoforming processes, conveniently at least 370 ° C, of preference of at least 380 ° C, more preferably at least 400 ° C, would be very desirable; Preferably, the modified rheology isotactic polypropylene would be more processable (or higher melt flow rate) than that formed in practice in US Pat. No. 3,336,268. Alternatively, it would be desirable to have a greater rheology modification than that obtained in the practice of the process disclosed in U.S. Patent No. 3,336,268, or to have at least one of higher ductility, resistance to Breakthrough traction, flexural modulus, Izod impact resistance, or MTS peak impact energy from what is obtained in the practice of the method disclosed. Alternatively, it would be desirable to have thermoplastic elastomers (TPE) and thermoplastic polyolefins (TPO) of high impact strength (preferably higher than 300 inches-pounds (34 Joules) as determined by ASTM D33763-93), which have a greater interfacial compatibility than mere mixtures of the constituent polymers, preferably having sufficient copolymers, or mixed with sufficient polypropylene to achieve high impact resistance, preferably having a propylene polymer and another polymer having more of 25 weight percent polyethylene or ethylene / alpha-olefin copolymer different from polypropylene. It would also be desirable to have a one step process or a container for preparing isotactic polypropylene of modified rheology. The present invention includes an improved process for the preparation of modified rheology polyolefins, either alone or as mixtures, which remain thermoplastic and melt-processable, and possess improved melt strength and other physical properties suitable for applications such as Thermoforming of large parts, blow molding, foaming, and injection molding. The invention includes a process for the preparation of a modified rheology polyolefin, which comprises a step of (a) heating a substantially uniform mixture of a polyolefin and a rheology modifying amount of a poly (sulfonyl azide) at a temperature, referred to below herein as a reaction temperature, which is at least the decomposition temperature of the poly (sulfonyl azide), especially where step (a) is preceded by a step (b) of forming the substantially uniform mixture in which step ( b) at least one polyolefin with 0.01 to 0.5 weight percent poly (sulfonyl azide) is mixed thoroughly, at a temperature, hereinafter referred to as a mixing temperature, which is at least the softening temperature of the polyolefin , but less than the decomposition temperature of the poly (sulfonyl azide), to form the substantially uniform mixture, and step (a) takes place at temperature at least 5 ° C above the mixing temperature, and at least the peak decomposition temperature of the poly (sulfonyl azide), and more particularly wherein both steps (a) and (b) take place in the same vessel. The process of the invention is particularly applicable to polyolefins comprising more than 50 mole percent of monomer having at least one tertiary hydrogen atom, preferably propylene polymers, more preferably wherein the propylene polymer has a lower molecular weight of 275,000, more preferably wherein the molecular weight is greater than 100,000 and less than 250,000. The polyolefin optionally comprises a mixture, subsequently in the present mixture, of at least one non-elastomeric polymer and at least one elastomeric polymer, wherein the non-elastomeric polymer is preferably a propylene polymer. The process preferably includes at least three temperatures, including the mixing and reaction temperatures, preferably between 160 ° C and 230 ° C, each temperature being different from the others by at least 5 ° C, with at least one temperature being of reaction at least 5 ° C above the decomposition temperature of the poly (sulfonyl azide), and at least one mixing temperature being at least 5 ° C above the softening temperature of the polyolefin and at least 5 ° C below the decomposition temperature of the poly (sulfonyl azide), and the three temperatures occurring inside a single container. The invention also includes a composition prepared by the process of the invention in any of its embodiments, this composition preferably comprising at least one modified rheology polyolefin made by a process comprising a step of (a) heating a substantially uniform mixture of a polyolefin, and a rheology modifying amount of a poly (sulfonyl azide) at a temperature, hereinafter referred to as a reaction temperature, which is at least the decomposition temperature of the poly (sulfonyl azide), whose composition conveniently has a higher melt strength in the extensional flow, or an easier melt flow at a high shear rate, compared to the polymer of the same weight-average molecular weight (Mw) having linear chains and the same composition, except for the coupled chains; a wider temperature range for thermoforming or a higher crystallization temperature than the polymers or polyolefins of the starting material. The invention further includes a composition comprising an isotactic polypropylene (PP) of modified rheology, or a modified rheological isotactic polypropylene / elastomer material which is the reaction product of at least one isotactic propylene polymer and optionally at least one polymer elastomeric with 0.01 to 0.5 weight percent, based on the total polymer, of a poly (sulfonyl azide), wherein at least one of the polymers is in a substantially uniform mixture with the poly (sulfonyl azide) before reacting with the polymer of propylene. The invention also includes a mixture composition comprising any composition of the invention, or any composition prepared by any process of the invention, this mixture preferably having a higher impact strength than a mixture of the same components without modified rheology or without chain coupled using a poly (sulfonyl azide).

Moreover, the invention includes any article that is thermoformed, injection molded, extruded, emptied, blow molded, blown, foamed, or molded articles of any composition of the invention, or prepared by a process of the invention, as well as any article that is a foam, film, or fiber of any composition of the invention, or prepared by a process of the invention, especially where that article is a reclining bed or refrigerator part, tub , or container. Accordingly, the invention includes a process for the preparation of a modified rheology polyolefin, which comprises a step (a) of reacting a polyolefin having a molecular weight less than 275,000, as measured by high temperature gel permeation chromatography. , with a poly (sulfonyl azide); that is, contacting this polyolefin and this poly (sulfonyl azide) under reaction conditions. The polyolefin is preferably a propylene homopolymer or copolymer. The invention also includes a process for the preparation of a modified rheology polyolefin, which comprises the step of (a) heating a substantially uniform mixture of a polyolefin and a rheology modifying amount of a poly (sulfonyl azide) at a temperature, referred to subsequently in the present as a reaction temperature, which is at least the decomposition temperature of the poly (sulfonyl azide). Step (a) is optionally preceded by a step (b) of forming the substantially uniform mixture in step (b) of which at least one polyolefin with 0.01 to 0.5 weight percent poly (sulfonyl azide) is thoroughly mixed, at a temperature, hereinafter referred to as a mixing temperature, which is at least the softening temperature of the polyolefin, but less than the decomposition temperature of the poly (sulfonylazide), to form the substantially uniform mixture. The preference process takes place using a temperature profile and more preferably step (a) has a reaction time sufficient for the decomposition of at least 80 mole percent of the poly (sulfonyl azide), more preferably for a time corresponding to at least 2 minutes at 230 ° C, and at least 4 minutes at 200 ° C. The preference process takes place in an extruder having a die through which the polymer is transported by at least one screw, an input element for the polymer, an outlet where the extruded polymer exits the die, and a mid point Between the input element and the outlet: Where the screw has more elements of high shear mixing between the input element and the midpoint of what it has between the midpoint and the outlet, whose extruder and screw are also aspects of the invention. The polymer preferably comprises at least one propylene polymer, more preferably a propylene polymer, which more preferably has a molecular weight of less than 275,000. In an alternative embodiment, the polyolefin comprises a mixture of at least one non-elastomeric polymer, and at least one elastomeric polymer. Additional aspects of the invention include compositions made by the process, as well as a composition comprising at least one non-elastomeric first polymer, and at least one second polymer which is an elastomeric polymer or a polyolefin, and which is at least 40% by weight. percent by weight of ethylene repeating units, and 0.01 to 0.5 percent by weight, based on the total polymer, of poly (sulfonyl azide). A further aspect of the invention includes a composition comprising an isotactic polypropylene (iPP) of modified rheology, or an isotactic polypropylene / modified rheology elastomer material which is the reaction product of at least one isotactic propylene polymer and optionally at least an elastomeric polymer with 0.01 to 0.5 percent by weight, based on the total polymer, of a poly (sulfonyl azide), wherein at least one of the polymers is in a substantially uniform mixture with the poly (sulfonyl azide), when the decomposition temperature of the poly (sulfonyl azide) is reached. which comprise any composition of the invention with at least one additional polymer, are also aspects of the invention. These mixtures preferably have a higher impact resistance than a mixture of the same components without modified rheology or without coupled chain, using a poly (sulfonyl azide). The articles formed from any composition of the invention, especially where the article is thermoformed, injection molded, extruded, emptied, blow molded, blown, foamed, or molded, or foam , film, or fiber, are included within the invention, as well as the use of any composition of the invention in any process of thermoforming, extrusion coating, injection molding, extrusion, casting, blow molding, foaming, film forming. , or blown. The invention further includes a process for contacting at least one polyolefin with a poly (sulfonyl azide) in a single container, wherein the contact includes mixing a. a temperature which is at least the softening temperature, preferably below the decomposition temperature of the poly (sulfonyl azide), and preferably followed by exposure to at least one temperature at which the poly (sulfonyl azide) is decomposed. The container is preferably an extruder. The polymer is preferably different from a solid volume form or solid particles, more preferably a molten or melted form, rather than a solution or dispersion for the mixture. In the invention, the polyolefin is optionally a homopolymer, copolymer, interpolymer, or blend, but preferably includes at least one propylene polymer. Figure 1 shows a comparison of shear viscosities of coupled chain propylene polymer formed in mixing devices of fixed temperature versus profiled temperature. The practice of the invention is applicable to any polyolefin, particularly a polyolefin having at least one tertiary hydrogen atom, ie, an alpha-olefin polymer having more than 2 carbon atoms (having an RCH = CH2 structure, wherein R is aliphatic or aromatic, and has at least one, and preferably less than 8 carbon atoms, whose olefins are polymerized to form base structures with tertiary hydrogen atoms). These alpha-olefins are optionally copolymerized with ethylene, other hydrocarbon monomers within the capability of the art, ie, hydrocarbons having one or more double bonds, at least one of which can be polymerized with the alpha-olefin monomer , or a combination thereof. Alpha-olefins having more than 2 carbon atoms include propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-nonane, 1-decene, 1-undecene, 1-dodecene, as well as 4 -methyl-1-pentene, 4-methyl-1-hexane, 5-methyl-1-hexane, vinylcyclohexane, styrene, and the like. The preferred alpha-olefin is propylene, which is optionally copolymerized with other addition polymerizable monomers, preferably olefins, more preferably alpha-olefins, including ethylene or combinations thereof. Not only polypropylene polymers are very difficult to modify using free radicals due to the formation of tertiary radicals and the resulting chain separation, but also the propylene repeating units have less spherical hindrance than the larger repeating units. Of the propylene polymers, those with isotactic or syndiotactic polypropylene chains on the atactic are preferred for the practice of the invention, and isotactic is more preferred because of its higher melting point and its usefulness in packaging and durable applications. In a similar way, styrene and substituted styrenes such as alpha-methylstyrene, are subject to chain separation when the rheology is modified with free radicals, and therefore, are the starting materials of the preferred embodiment for the practice of the present invention. Optionally, but not in the most preferred embodiment, the polymers have monomers having at least two double bonds that are preferably dienes or triplets. Suitable diene and triene comonomers include 7-methyl-1,6-octadiene, 3,7-dimethyl-1,6-octadiene, 5,7-dimethyl-1,6-octadiene, 3,7, 11-trimethyl- 1, 6,10-octatriene, 6-methyl-1,5-heptadiene, 1,3-butadiene, 1,6-heptadiene, 1,7-octadiene, 1,8-nonadiene, 1,9-decadiene, 1 10-undecadiene, norbornene, tetracyclododecane, or mixtures thereof, preferably butadiene, hexadienes, and octadienes, more preferably 1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene , dicyclopentadiene, and 5-ethylidene-2-norbornene. Polyolefins are formed by elements within the experience of the technique. The alpha-olefin monomers, and optionally other addition polymerizable monomers, are polymerized under conditions within the field experience, for example, as disclosed by Galli et al., Angew. Macromol Chem., Volume 120, page 73 (1984), or by E.P. More, and collaborators in Polypropylene Handbook, Hanser Publishers, New York, 1996, particularly pages 11-98. The polyolefins of the starting material preferably lack demonstrable and measurable long chain branches, ie they have less than 0.01 long chain branches, or chains coupled per 1,000 carbon atoms, as measured by the methods described by Randall in Rev. Macromol. Chem. Phvsic. C29, V.2 & 3, pages 285-297, and Zimm et al. J. Chem. Phys. 17, 1301 (1949) and Rudin, Modern Methods of Polymer Characterization, pages 103-112 John Wiley & Sons, NY 1991. The monomers are used in any relative amounts, but preferably having a majority of the tertiary hydrogen monomer (having more than 50 mole percent of the monomer, at least one tertiary hydrogen atom), more preferably being the majority ( more than 50 mole percent) of the monomers, propylene, more preferably at least 90 mole percent propylene. Polymers having at least 50 mole percent of propylene units are referred to herein as polymers of propylene or polypropylenes. However, optionally, the practice of this invention includes other hydrocarbon polymers, such as polystyrene, poly (styrene-co-acrylonitrile), polyvinylcyclohexane, polybutadiene, polyisoprene, cyclic olefin copolymers, and copolymers, and the like, and mixtures thereof. same. Polymers having at least 50 mole percent styrene or substituted styrene units are referred to herein as styrenic polymers. The polymer starting materials are suitably of any molecular weight distribution (MWD). For example, polymers of narrow molecular weight distribution are formed within the skill of the art, and are used in a process of the invention to produce coupled chain polymers of a suitably narrow molecular weight distribution of the which would be formed in a coupling process involving chain separation, for example, by free radicals with the same starting materials. Alternatively, a polymer or copolymer of a broader molecular weight distribution used as a starting material in the practice of the invention, results in a product having a similarly broad molecular weight distribution, rather than the distribution of typically narrow molecular weight observed in branched products formed with metallocene or with catalysts of limited geometry that are known to result in both branching and narrow molecular weight distribution. However, it is preferred that the polymers of the starting material have a narrow molecular weight distribution, because the melting point is broadened after coupling according to the practice of the invention, more than what is observed for polymers of starting material of a broader molecular weight distribution. This expanded melting point widens the processing window for manufacturing, such as thermoforming, blow molding, film making and foaming. Preferably, the molecular weight distribution of the starting polymer is less than 4.0, more preferably less than 3.0. and most preferably less than 2.5. Optionally, the polymers that are to be used as starting materials in the practice of the invention are mixtures of polymers. Preferably, each polymer of the mixture is independently selected from the polyolefins described above. More preferably, at least one of the polymers is a propylene polymer. More preferably, at least one polymer is a propylene polymer, and at least one polymer is an ethylene homo- or co-polymer with at least one other addition polymerizable monomer, preferably at least one olefin, more preferably at least one alpha -olefin, and most preferably propylene. In the case of blends, particularly thermoplastic polyolefins and thermoplastic elastomers, more than one polymer, preferably polyolefin, is used. In thermoplastic polyolefin materials, preferably the ethylene / alpha-olefin copolymer (preferably with at least 40 weight percent ethylene) is dispersed in, or in a co-continuous manner with, for example, a phase of polypropylene. A thermoplastic elastomer is a polymer of separate phases that contains different hard and soft segments where the hard segments reinforce the soft phase, but it is not reticulated in a network, that is, it is still thermoplastic; the preferred thermoplastic elastomer materials possess a polypropylene phase dispersed in an ethylene / alpha-olefin elastomer. In the practice of the invention, the polyolefin is reacted with a chain coupling agent which is a poly (sulfonyl) azide. When the poly (sulfonyl) azide reacts with the polyolefin, at least two separate polyolefin chains are conveniently joined, and the molecular weight of the polymer chain is increased. In the preferred case, when the poly (sulfonyl azide) is a bis (sulfonyl azide), two polyolefin chains are conveniently attached. The poly (sulfonyl azide) is any compound having at least two sulfonylazide groups (-SO2N3) that react with the polyolefin. Preferably, the poly (sulfonyl azide) s have an XRX structure, wherein each X is SO2N3, and R represents a hydrocarbyl, hydrocarbyl ether, or silicon-containing, unsubstituted or inertly substituted, group preferably having sufficient carbon atoms, oxygen or silicon, preferably carbon, to separate the sulfonylazide groups sufficiently to allow an easy reaction between the polyolefin and the sulfonylazide, more preferably at least 1, most preferably at least 2, and more preferably at least 3 carbon atoms, oxygen or silicon, preferably carbon, between the functional groups. Although there is no critical limit for the length of R, each R conveniently has at least one carbon or silicon atom among the X's, and preferably has less than 50, more preferably less than 20, and most preferably less than 15 atoms of carbon, oxygen or silicon. Silicon-containing groups include silanes and siloxanes, preferably siloxanes. The term "inertly substituted" refers to the substitution with atoms or groups that do not undesirably interfere with the desired reactions, or with the desired properties of the resulting coupled polymers. These groups include fluorine, aliphatic or aromatic ether, silyxane, as well as sulfonylazide groups when more than two polyolefin chains are to be joined. R is suitably aryl, alkyl, arylalkaryl, arylalkylsilane, siloxane or heterocyclic groups, and other groups which are inert and which separate the sulfonylazide groups, as described. More preferably, R includes at least one aryl group between the sulfonyl groups, more preferably at least two aryl groups (such as when R is 4,4'-diphenyl 64,4'-biphenyl ether). When R is an aryl group, it is preferred that the group has more than one ring, as in the case of naphthylene bis (sulfonyl azides). The poly (sulfonyl) azides include compounds such as bis (sulfonyl azide) 1,5-pentane, bis (sulfonyl azide) 1,8-octane, bis (sulfonyl azide) 1,10-decane, bis (sulfonyl azide) 1. 10-Octadecane, tris (sulfonyl azide) of 1-octyl-2,4,6-benzene, bis (sulfonyl azide) of 4,41-diphenyl ether, 1,6-bis (41-sulfonazidophenyl) -hexane, bis (sulfonylazide) of 2,7-naphthalene, and mixed sulfonyl azides of chlorinated aliphatic hydrocarbons containing an average of 1 to 8 chlorine atoms, and 2 to 5 sulfonyl azide groups per molecule, and mixtures thereof. Preferred poly (sulfonyl azide) s include oxy-bis (4-sulfonylazidobenzene), 2,7-naphthalene bis (sulfonyl azide), 4,4'-bis (sulfonylazido) biphenyl, ether bis (sulfonylazide) 4,4'-diphenyl, and bis (4-sulfonylazidophenyl) methane, and mixtures thereof. The sulfonylazides are conveniently prepared by the reaction of sodium azide with the corresponding sulfonyl chloride, although the oxidation of the sulfonyl hydrazines with different reagents (nitrous acid, dinitrogen tetroxide, nitrosonium tetrafluoroborate) has been used. The sulfonilazides are broken down in various ways, but, for the practice of the invention, the reactive species which are believed to be the singlet nitrene as evidenced by the insertion into the C-H bonds are desired. The photochemical decomposition of the sulfonylazides proceeds by intermediate radicals, and in general does not provide an efficient preparation path towards the singlet materials, and is therefore preferably avoided in the practice of the invention. However, thermal chemistry is much more selective. It is reported that thermal decomposition gives an intermediate singlet sulfonylnitrene, which reacts easily by inserting it into the carbonhydrogen bonds. The high temperatures necessary for an efficient formation of the sulfonylnitrene, are usually greater than 150 ° C. Sulfonyl azides are convenient because the singlet nitrene initially generated does not cross-system to nitrene in the triplet state, as singlet nitrenes generated from formyl or aryl azides easily do. The greater stability of the singlet translates into less selectivity on the part of the sulfonylnitrenes for the insertion of the primary carbon-hydrogen bond, compared with the secondary, and compared with the tertiary. However, there is some selectivity between the alkyl and aromatic systems, the latter being twice as reactive. Additionally, although arylazides will not react with aromatic systems, formyl azides will do so, providing predominantly azepine products. The sulfonyl azides also form another intermediate that is believed to be a triplet nitrene under conditions such as temperatures greater than 250 ° C. This intermediate leads to chain separation, and consequently, the practice of this invention is preferably avoided. Those skilled in the art recognize that the reactivity, the poly (sulfonyl) azide, and the desired or previously determined rheology, or the amount of chain coupling, determine the amount of poly (sulfonyl) azide to be used. The determination of this amount is within the experience of the technique. In the practice of the invention, the formation of cross-linked networks should be avoided, because the resulting material would be intractable; therefore, the poly (sulfonyl azide) is preferably limited to the amount that results in a coupled chain or modified rheology polyolefin (but not substantially crosslinked), preferably less than 0.5, more preferably less than 0.20 percent by weight , and most preferably less than 0.10 weight percent of poly (sulfonyl azide), based on the total weight of the polyolefin, preferably polypropylene or a polypropylene / ethylene copolymer blend. The crosslinking is evidenced by the gel formation which is measured in the case of polypropylene by the insolubility in xylene. In the practice of the invention, the resulting polymers preferably have less than 5 percent by weight, more preferably less than 2 percent by weight, and most preferably less than 1 percent by weight of xylene insolubles, as measured by ASTM D2765 (procedure A). The term "a rheology modifying amount" of the poly (sulfonyl azide), is used herein to designate the amount of poly (sulfonyl azide) effective to modify the rheology of the polymer with which it reacts, such that it is formed no further of 5 weight percent gel insoluble in xylene. Conveniently at least 0.01 weight percent poly (sulfonyl azide) is used to achieve measurable results, preferably at least 0.02 weight percent, and most preferably at least 0.05 weight percent poly (sulfonyl azide), based on the total weight of the polymers. The decomposition temperature of the azide means the temperature at which the azide is converted to the sulfonylnitrene, eliminating nitrogen, and more heat in the process. Specifically, the peak decomposition temperature is determined by differential scanning calorimetry (DSC). For example, a thermogram of the differential scanning calorimeter (DSC) of bis (sulfonyl azide) diphenyl oxide shows no change in heat flux until an acute endothermic melting peak at 100 ° C is observed. The baseline is flat again (no heat flow), until a broad exothermic peak starting at 150 ° C is observed, and the peak is at 185 ° C (referred to herein as the peak decomposition temperature), and it is finished up to 210 ° C. The total amount of energy released due to the decomposition of the sulfonyl azide groups is 1,500 Joules / gram. The peak decomposition temperature is conveniently greater than 150 ° C, preferably higher than 160 ° C, and most preferably higher than 180 ° C. The polyolefins and the poly (sulfonyl azide) are suitably combined in any way that results in a desired reaction thereof, preferably by mixing the poly (sulfonyl azide) with the polymers under conditions that allow sufficient mixing prior to the reaction, for avoid irregular amounts of localized reaction, and then the resulting mixture is subjected to sufficient heat for the reaction. Preferably, a substantially uniform mixture of poly (sulfonyl azide) and polymer is formed before being exposed to conditions where chain coupling takes place. The term "substantially uniform mixture" means a mixture wherein the distribution of the poly (sulfonyl azide) in the polymer is sufficiently homogeneous to be evidenced by a polymer having a melt viscosity after treatment in accordance with the practice of the invention, higher at a low angular frequency (eg, 0.1 rad / sec) than that of the same polymer treated with the same amount of poly (sulfonyl azide) mixed with the polymer at a temperature where the polymer is solid, instead of above of its softening temperature, in another liquid form, such as a solution or dispersion in a liquid. Accordingly, preferably, in the practice of the invention, the decomposition of the poly (sulfonyl azide) occurs after sufficient mixing to result in a substantially uniform mixture of poly (sulfonyl azide) and polymer. This preferred mixture is obtained with the polymer in a molten or melted state, ie, above the softening temperature, or in a dissolved or finely dispersed condition, instead of a solid mass or a particulate form. The molten or melted form is more preferred, due to the absence of solvent that has to be removed. Those skilled in the art recognize that a polymer or mixture thereof melts over a range of temperatures rather than melting sharply at a temperature. For the practice of the invention, it is sufficient that the polymer be in a partially molten state, recognized by the formation of a substantially uniform mixture, as defined above. For convenience, the temperature of this melting degree can be approximated from a differential scanning calorimeter (DSC) curve of the polymer or the mixture thereof to be treated. The temperature necessary to form a substantially uniform mixture is facilitated by comparing a differential scanning calorimetry curve of the melt flow against the temperature of a polymer with the poly (sulfonyl azide) of interest, to find the reaction profile of the poly (sulfonyl azide), and a differential scanning calorimetry curve of the polymer where the poly (sulfonyl azide) is to be used. For example, the reaction temperature profile of oxy-bis (4-sulfonylazidobenzene) shows a reaction setting above 150 ° C, with a peak decomposition temperature of 185 ° C. Accordingly, the polymers can be mixed in a substantially uniform mixture with the poly (sulfonyl azide), at temperatures between the softening temperature (as indicated by the establishment of softening in the differential scanning calorimetry curve) and the melting temperature. (where the melting is completed), before reaching the decomposition temperature of the poly (sulfonyl azide). Conveniently, the formation of a substantially uniform mixture occurs along a temperature profile in equipment such as an extruder. Any equipment is suitably used, preferably equipment that provides sufficient mixing and temperature control in the same equipment, but conveniently, the practice of the invention takes place in devices such as an extruder, a melting mixer, a pump conveyor, another polymer mixing device, such as a Brabender melting mixer. The term "extruder" is used in its broadest sense to include devices such as a device that extrudes granules or a granulator. Preferably, the equipment allows to have a sequence of temperatures or zones that have different temperatures. The reaction is especially suitable for an extruder, because the practice of the invention can be presented in a single container (i.e., any single piece of equipment capable of containing the polymer) preferably causing sufficient mixture to be present at a temperature of softening the polymer, more preferably before there is sufficient heat to raise the polymer mass to the peak decomposition temperature of the poly (sulfonyl azide). Conveniently, when there is a melt extrusion step between the production of the polymer and its use, at least one step of the process of the invention takes place in the melt extrusion step. Although it is within the scope of the invention for the reaction to take place in a solvent or other medium, it is preferred that the reaction be in a bulk phase, to avoid further steps to remove the solvent or other medium. For this purpose, a polymer above the softening temperature for a uniform mixture is desirable, and to reach a reaction temperature (the decomposition temperature of the sulfonyl azide).

In a preferred embodiment, the process of the present invention takes place in a single vessel, that is, the mixture of the poly (sulfonyl azide) and the polymer takes place in the same vessel as the heating to the decomposition temperature of the poly ( sulfonilazide). The container is most preferably a twin screw extruder, but preferably a single screw extruder, or cniently a melt mixer, including a batch mixer. The reaction vessel more preferably has at least two zones of different temperatures at which the reaction mixture would pass, the first zone being cniently at a temperature which is at least the softening temperature of the polymers, and preferably less than the temperature of decomposition of the poly (sulfonyl azide) s, and the second zone being at a temperature sufficient for the decomposition of the poly (sulfonyl azide). The first zone of preference is at a temperature high enough to soften the polymer and allow it to combine with the poly (sulfonyl azide) through a distributive mixture, to a substantially uniform mixture. Especially in the case of propylene polymers, more preferably polyolefins and poly (sulfonyl azide) are exposed to a temperature profile from 160 ° C to 220 ° C. The term "profile" is used herein to mean a series of temperatures to which the polymer is exposed, with each temperature being at least 5 ° C, preferably at least 10 ° C higher than the previous temperature. The series preferably comprises at least one temperature which is at least the softening temperature of the polymers, and at least one which is at least the decomposition temperature of the poly (sulfonyl azide), more preferably the profile comprises at least 3, and most preferably at least 4 of these temperatures, wherein, in addition to at least one temperature, at least the softening temperature and at least the decomposition temperature, the polymer is optionally exposed to temperatures between these temperatures, and optionally to at least a temperature above the decomposition temperature of the poly (sulfonyl azide), more preferably including at least a temperature that is at least 5, more preferably at least 10, and still more preferably at least 15 ° C greater than the decomposition temperature. In the description of this invention, when the temperatures are described in terms of the softening or decomposition temperatures, the temperatures are the temperatures of the stream, that is, the temperatures inside the polymer stream or polymer melt, instead of equipment temperatures, which is understood by those skilled in the art who are likely to be higher or higher than current temperatures, due to imperfect heat transfer to the polymer, or heating induced shear stress of the polymer. The experts in this field can determine the relationship between the temperature of the current and the temperature of the equipment or the meter of the particular equipment without undue experimentation. It is known in the art that the melting temperature of the polymer (stream) is cniently close to the temperature set by the machine in the initial zones of an extruder, but the melting temperature of the polymer (stream) can often be higher than temperatures established by the machine in the last zones of the extruder, as it approaches the output die of the extruder, due to the heating mechanically induced by the shear stress. However, processing temperatures and polymer melting temperatures greater than 250 ° C can lead to a degradation of the molecular weight of the product instead of the chain coupling. The representative data show that at 200 ° C, the melt viscosity of the isotactic polypropylene is greatly elevated due to the reactive chain coupling by means of the poly (sulfonyl) azide compound, and then leveled or lowered slightly due to heating by the shear stress. In contrast, when the reaction is run at a higher temperature (approximately 250 ° C), an acute elevation in the melt viscosity due to chain coupling is not observed, and the viscosity actually decreases as a function of time, indicating a decrease in molecular weight that is believed to be due to chain separation reactions. Accordingly, in the practice of the invention, temperatures of 250 ° C or higher are preferably avoided, while there is still enough unreacted poly (sulfonyl azide) in the reaction mixture, to result in more than 1 weight percent of polymer having a molecular weight less than that of the starting material, measured by the weight average molecular weight of the polymer by gel permeation chromatography. In a similar way, chain separation is observed when there are free radicals present from other sources, such as peroxides; accordingly, unless chain separation is desired, free radical sources are preferably avoided in the practice of the invention. The temperature is maintained at least at the decomposition temperature for a sufficient time to result in the decomposition of at least sufficient poly (sulfonyl azide) to avoid an undesirable subsequent reaction, preferably at least 80 is reacted, more preferably at least 90, and most preferably at least 95 weight percent of the poly (sulfonyl azide). The experts in this field will realize that this time depends on whether the temperature is one at which the azide decomposes slowly, or one which decomposes very rapidly. For convenience, the temperatures are selected such that the times are preferably less than 5 minutes, more preferably less than 2 minutes. However, it is also preferable that the times be at least 1 minute, more preferably at least 2 minutes, to avoid having unreacted poly (sulfonyl azide) and subsequent undesirable reactions, or to avoid the need for temperatures inconveniently, and possibly destructively high In the case of the preferred poly (sulfonyl azides), which have at least two sulfonylazide groups on separate aromatic rings, whose rings are not conjugated, such as 4,4'-diphenyl bis (sulfonyl azide), preferably a final temperature is used at least 230 ° C for a period of at least 2 minutes. At temperatures near 200 ° C, the preferred times are at least 4, and more preferably at least 5 minutes. The preferred reaction times (tr) in minutes for the reactions between and corresponding to 4 minutes at a reaction temperature (RT) of 200 ° C, and 2 minutes at a reaction temperature of 230 ° C, can be approximated linearly by The equation: tr = 4 - (TR - 200).

Although it is particularly useful to practice the present invention inside an extruder or a granulator (the latter preferably as a step in polymer production), conventional extruder screws are less than optimal for the practice of the invention. Typically, the high shear mixing elements are closer to the die exit term of the extruder. In the practice of the invention, in an extruder having a die through which the polymer is transported by at least one screw, an input element for the polymer (for example, a feed gate), an outlet where it leaves the polymer extruded from the die: it is preferred to have high shear mixing elements before in the extruder, more preferably more high shear mixing elements between the input element and the mid point than between the mid point and the outlet, where the Midpoint is the midpoint between the input element and the output. An extruder screw for use in a preferred embodiment of this invention has a nominal ratio of length to diameter L / D) of at least 28, preferably at least 30, more preferably 40, and most preferably less than 48, for the purpose of achieving a sufficient residence time for the mixing and reaction of the poly (sulfonyl azide) with the polymer, especially a propylene polymer. In addition, the design of the screw includes multiple mixing zones, at least two, each of which zones conveniently includes at least one type of mixing element within the capability of the technique (preferably selected from the AMT type (i.e. Advanced Mixing Technology), of the type of kneading block, of the type of gear mixer, of the modified conveyor type). A preferred embodiment includes AMT screw having variations in height, or the presence of blade sections on interengaged twin screws rotating together, or changing or different blade numbers on pairs of elements having the same axial position on different arrows of those screws, for example, as disclosed in the TCP Application Number 97/17007, published as WO 98/13189, and the pending United States Application Serial Number 08/935626 filed on September 23. of 1997, and Pending Application Serial Number 08/974185, filed on November 19, 1997. AMT Technology allows complete mixing without sufficient temperature increases from the mixing process itself, resulting in premature reaction with the poly (sulfonyl azide) before a substantially uniform mixture is obtained. For the practice of the invention, each screw preferably has a solids transport zone, followed by at least one kneading block section, where the melting occurs, followed by at least two, and more preferably at most 8 zones of mixture. Each mixing zone is separated from the adjacent mixing zone by a change in the type of mixing element, or a transport zone following a mixing zone. Optionally, each mixing zone independently includes at least one conveyor element for pumping the polymer to the mixing elements, from the mixing elements or both to and from the elements. The residence time of control is within the experience in this field, through the selection of the length of the extruder (L / D), and the placement of the fusion zone sufficiently far from the term of the extruder (discharge orifice) , to give the time required for the reaction in the merger. The temperature inside the molten polymer (melting temperature) is strongly affected by the length of the reaction zone, since heat is generated by the viscous dissipation in the melt transport regions. The handling of temperature and the distributive mixture are conveniently carried out using alternating zones of mixing elements. The result of the process of the invention is a coupling of one polymer chain with another by means of sulfonamide bonds., preferably -NSO2RSO2N- when the poly (sulfonyl azide) is XRX. When the polymer chains are coupled or bonded in this manner, they are referred to herein as "chain coupled" polymers, and as modified rheology polymers. Conveniently, the coupled chain polymers behave Theologically, similarly to branched polymers of a corresponding composition having branches of at least 20 carbon atoms. For example, the viscosity of the solution (or the intrinsic viscosity) increases with the molecular weight, and the melt flow rate increases. Accordingly, in the practice of the invention, the linear polymers are converted into polymers having non-linear chains. The resulting polymer is obtained as a solid thermoplastic polymer, which conveniently has a melt viscosity of low shear stress at least as large as that of the starting material, and a melt strength greater than that of the starting material. Conveniently, the resulting polymer has a weight average molecular weight greater than that of the linear polyolefin starting material (before inter-chain coupling), preferably at least 5 percent larger, more preferably at least 10 percent higher, and most preferably at least 20 percent higher. The resulting polymer suitably has chain coupling of the long polymer chains, ie, the chains of at least 20 carbon atoms, as evidenced by the changes in rheology. In the embodiment of the invention wherein the starting materials of the polymer have tacticity, the coupling of long polymer chains is preferably of chains having the same stereoisomeric structure as the base structure, i.e., isotactic polypropylene chains (i-PP ) in isotactic polypropylene, syndiotactic chains in syndiotactic polymers, and atactic chains in atactic polymers, for the purposes of maintaining the desired properties associated with each stereoisomeric structure. However, in the case where this invention is practiced on mixtures of two or more polyolefin polymers of different tacticity, the coupling of polymer chains of different tacticity may be desirable from a point of view of the end use (for example, to obtain a scale of extended melting point, hardness, etc.). In addition, the resulting coupled chain polymers are conveniently observed to have a better stress hardening, as demonstrated by the tensile stress growth coefficient. The resulting polymer is used alone, or is mixed with other polymers, conveniently similar polymers, preferably polypropylene polymers, having different amounts, preferably less or no polymer chain coupled. The polymers resulting from the practice of the present invention, and the compositions that include them, preferably have a better resistance to melting, and therefore, are highly desirable for molding operations where a melt strength is more desirable. high, such as injection blow molding, high speed extrusion coating, thermoforming, profile extrusion, and coextrusion in multiple layers, all of which are within the skill of the art. In a similar manner, the polymers resulting from the practice of the invention are particularly suitable for the formation of films and foams, due to their viscosity and their shear viscosity properties. In the practice of this invention to form coupled chain propylene polymers or other polyolefins, it is convenient to use an isotactic polypropylene of lower molecular weight as a starting material (in contrast to the teachings of the U.S. Patent Number 3, 336, 256 where the use of polypropylene having a molecular weight of at least 275,000) is claimed for two different reasons. First, if the poly (sulfonyl) azide reacts at one end with an isotactic polypropylene molecule of lower molecular weight, the probability of reaction of the second sulphonyl azide group on the poly (sulfonyl azide) with a different isotactic polypropylene molecule is statistically greater . The use of isotactic polypropylene of high molecular weight increases the probability of formation of cyclic structures resulting from the reaction of the poly (sulfonyl) azide at different places along the chain of the same polypropylene molecule (coupled intra-chains). These cyclic structures do not impart better melt viscosities at low shear rates, as do long-chain branched polymers, and inter-chain coupled polymers. Second, the use of a lower molecular weight isotactic polypropylene allows greater control over the degree of chain coupling, so that a wider range of melt flow velocity materials can be obtained than can still be achieved. process. Frequently, very low melt flow rates are undesirable (<3 grams / 10 minutes at 230 ° C), because these materials are difficult to process and manufacture, using the most widely available equipment. Accordingly, the polypropylenes to be chain coupled by the process of the invention, preferably have a molecular weight less than 275,000, more preferably less than 250,000, and most preferably less than 225,000. Preferably, the polypropylenes have a molecular weight of at least 100,000, more preferably at least 150,000, and most preferably at least 180,000. These molecular weights are weight average molecular weights, measured by gel permeation chromatography. Another embodiment of the invention is the use of the process of the invention on mixtures to improve the physical properties, such as the impact resistance, the rigidity, the heat resistance, the scratch resistance and the spoilage, the processability, of these mixtures, comparing with mixtures of the same components not treated by the process of the invention. Mixtures are mixtures of at least two polymers, at least one of which is preferably a polyolefin polymer (A), more preferably a propylene polymer, as defined above. The other polymer (B) is preferably a polyolefin, such as a propylene / alpha-olefin copolymer, polyethylene, ethylene / alpha-olefin copolymer, or mixtures thereof. The alpha-olefin monomer is an alpha-olefin of 2 to 12 carbon atoms capable of copolymerizing with ethylene or propylene. Examples include 1-butene, 1-pentene, 1-hexene, 1-octene, and the like. Olefins of 2 to 12 carbon atoms are preferred, and olefins of 2 to 10 carbon atoms are more preferred, and olefins of 2 to 8 carbon atoms are still more preferred. The polymer A preferably contains propylene, and optionally from 0 to 20 weight percent of alpha-olefin other than propylene, more preferably from 0 to 10 weight percent of another alpha-olefin, and more preferably from 0 to 5 by weight. one hundred percent by weight of another alpha-olefin. The polymer B preferably contains ethylene, and optionally from 0 to 60 percent by weight of alpha-olefin other than ethylene, more preferably from 20 to 60 percent by weight of another alpha-olefin, and most preferably from 40 to 60 percent by weight. one hundred percent by weight of another alpha-olefin. Treatment of these blends with the poly (sulfonyl azide) in accordance with the practice of the invention, as described for the polypropylene previously, results in blends of the invention, the blends of which are preferably thermoplastic elastomers when a polyolefin is the continuous phase , and for example, polypropylene is the dispersed phase, or thermoplastic polyolefins when, for example, polypropylene is the continuous phase. These mixtures of the invention are referred to herein as coupled chain blends, reactively coupled, or coupled. A mixture is conveniently mixed with a poly (sulfonyl azide) above the softening temperature of at least one component of the mixture, more preferably below the decomposition temperature of the poly (sulfonyl azide), and the resulting mixture is preferably raised to at least the decomposition temperature of the poly (sulfonyl azide), as in the case of the treatment of a propylene polymer with the poly (sulfonyl azide). As in the case of a single polymer, the application of the practice of the invention to blends conveniently involves forming a substantially uniform mixture of polymers and poly (sulfonyl azide) prior to the decomposition of the poly (sulfonyl azide), although in the case of mixtures in which there are dispersed and continuous phases, it is sufficient that the poly (sulfonyl azide) is dispersed at the interface of the phases, instead of evenly distributed in particular in the dispersed phase, unless the chain coupling of the dispersed phase itself. In a more preferable way, the poly (sulfonyl azide) and the resulting coupling is distributed primarily at the interface of the different polymers. The distribution primarily in the inferred, conveniently is achieved by the addition of the polyazide after the two immiscible polymers have been mixed, to the extent that a minimum dispersed polymer particle size has been reached. This allows the maximum amount of interfacial surface area to be available for the polyazide reaction. Where there are dispersed and continuous phases, it is more preferable, but not necessary, to add the poly (sulfonyl azide) after the mixture of two or more polymers is well mixed, that is, at a point where the particle size of the polymer dispersed has reached the smallest size practically achievable in the particular mixer device used. At least one of the polymer components of the mixture is preferably at least at its softening temperature. More preferably, the mixture is presented or continued when the mixture is at a temperature sufficient for the poly (sulfonyl azide) to react, to form a reactive species which is believed to be a singlet nitrene capable of being inserted into the bonds of carbon-hydrogen, that is, at its decomposition temperature. This allows an optimal reaction at the interface between the two polymers. Although it is preferred that the mixture of the mixture and the poly (sulfonyl azide) precede an increase in temperature up to the decomposition temperature, alternatively, the mixture occurs at or above the decomposition temperature of the poly (sulfonylazide) . It is believed that the best impact resistance exhibited by the thermoplastic polyolefins of the invention results from the formation of polymers coupled between the components of the mixture, for example thermoplastic polyolefin or thermoplastic elastomer, for example, ethylene / octene materials coupled with polypropylene isotactic, at the site from the reaction of a polypropylene molecule and a polyolefin with a poly (sulfonyl azide). Then this coupled polymer would act as a compatibilizer for the immiscible isotactic polypropylene and the ethylene / octene elastomer, and lower the interfacial tension between the components of the mixture. It is believed that the result is a finer dispersion of ethylene / octene in isotactic polypropylene, or a coupling of dispersed particles with the continuous phase polymer leading to better impact properties. The amount of poly (sulfonyl azide) used to treat blends by practicing the invention, is a sufficient amount to result in better impact strength of the blend, especially thermoplastic polyolefins, especially for increased modules of the thermoplastic elastomer at temperatures where comparable mixtures begin to show a reduced modulus, preferably above 60 ° C, more preferably above 70 ° C, and most preferably above 80 ° C, or to reduce the average particle size of the dispersed phase, as observed by the electron microscope, comparing with a mixture of the same components formed with the same mixture and some other conditions, but without the reaction with the poly (sulfonilazide). Impact strength and modulus are measured by any element within the skill of the art, eg, Izod impact energy ASTM D 256, MTS Peak Impact Energy (dart impact) ASTM D 3763-93, Impact Energy Total MTS, ASTM D-3763, or flexural module ASTM D 790. This amount is preferably at least 0. 01, and preferably less than 0. 5, more preferably less than 0.3, and most preferably less than 0.2 per weight percent of poly (sulfonyl azide), based on the total weight of the polymers in the mixture. A mixture of the invention where a polyolefin is continuous, for example an ethylene-octene elastomer, with a dispersed isotactic polypropylene phase, is generally categorized as a thermoplastic elastomer (TPE). The rigid phase (sotactic polypropylene) reinforces the elastomer, which allows its use in higher temperature applications. An approach for the preparation of thermoplastic elastomers based on polyolefins, is to mix high density polyethylene or isotactic polypropylene in the elastomeric materials. However, without some degree of interfacial bonding (coupling), the properties of these materials are lower than those measured by the behavior of the module against the temperature obtained using dynamic mechanical spectroscopy. Peroxides can be used to perform interfacial bonding in polyethylene-based systems, but peroxides are inconvenient with polymers such as isotactic polypropylene, because chain separation reactions occur. However, through the use of poly (sulfonyl azide) coupling chemistry, true thermoplastic elastomers demonstrating superior temperature performance can be prepared, compared to control systems. As described above for the thermoplastic polyolefins, the formation of coupled polymers, for example isotactic polypropylene fractions coupled with ethylene / octene, at the site, is believed to lead to a lower interfacial tension between the components of the mixture, giving as resulting in a much finer dispersion of, for example, isotactic polypropylene in the ethylene / octene elastomer, or the coupling of the dispersed phase with the continuous phase. In addition it is believed that these coupled species tend to be located at the interface between the elastomer and the isotactic polypropylene, resulting in a better stress transfer between the phases. By using the improved dispersion of one polymer phase in another, or a combination thereof, with the interface reinforced between the phases, an equivalent impact can be conveniently obtained, particularly a low temperature impact with less scattered phase, with a greater modulus, heat stability, processability, or a combination thereof, at a lower cost. Resistance to scrapes and damage is also preferably improved. Conveniently, better impact properties can be obtained, for example by including the Izod impact, compared to a polymer blend (eg, thermoplastic polyolefin) with the same amount and type of dispersed phase, but not coupled with poly (sulfonyl azide) . Alternatively, less impact modifier (elastomer) can be used to obtain equivalent impact performance with the practice of the invention, than with the same components without poly (sulfonyl azide) coupling. Alternatively, the impact of high-flux polypropylene can be modified more efficiently (eg, a melt flow rate greater than or equal to 35 grams / 10 minutes) for articles of lower caliber (thickness lower), such as the face of the fenders for automotive applications, as well as other durable molded articles. A first impact modifier is considered more efficient than a second impact modifier when less of the first impact modifier is required than the second, to obtain equivalent impact performance, or when the same modifier is used in the same modifier, the use of the first modifier Impact results in greater impact resistance than the use of the second. In an alternative way, the practice of the invention allows thermoplastic elastomers to have isotactic polypropylene as the dispersed phase to obtain a thermoplastic elastomer with higher rigidity (modulus) at higher temperatures than a corresponding thermoplastic elastomer with high density polyethylene (HDPE). as the dispersed phase. In a convenient way, a thermoplastic polyolefin prepared by a process of the invention, also has low temperature ductility, measured by the dart impact test or improved instrumented notched Izod impact on that of a thermoplastic polyolefin of the same components, but not treated with poly (sulfonyl azide) in accordance with the practice of the invention. Thermoplastic polyolefins and modified impact polypropylenes coupled in accordance with the practice of the invention are particularly useful as large parts, such as bed linings for pickup trucks, tubs, and parts of refrigerators, such as door liners, because to the reduced sinking that facilitates thermoforming. The best chemical resistance, for example, to insulation blowing agents, also improves the use as refrigerator parts and vessels. The modified rheology resins, which are presented of the chain coupling reactions described in this invention, exhibit more resistance to flow, in flows dominated by extension (extensional flows). The resistance, for example, some rises 100 times after the chain coupling, as indicated by a 100-fold rise in the tensile stress growth coefficient? E +. These resins are considered resins of high resistance to fusion by those skilled in the art, due to their high values of E + [See, Montell Patents US 5,554,668; European Patent Number 01908891. The highest melt strength in the extensional fluxes relative to the linear chains with the same weight average molecular weight Mw and for the same temperature is useful, for example, in the extrusion coating, film production, and thermoforming. In contrast, in flows dominated by shear stress, modified rheology resins exhibit higher flow resistance at low shear rates, and low flow resistance at high shear rates relative to linear chains, with the same weight molecular weight in absolute weight Mw, and for the same temperature. Resistance, for example, sometimes rises 100 times after chain coupling, as indicated by a 100-fold rise in the dynamic shear viscosity coefficient coefficient at a low angular frequency (0. 01 rad / second) , but can fall dramatically to those of the chains not coupled to a high angular frequency (100 rad / second). In a similar way, the dependence on the flow resistance on the shear rate will follow that of the angular frequency based on the Cox-Merz rule [W.P. Cox and E.H. Merz, J. Polym. Sci 28: 619, 1958]. An easy melt flow at high shear rates relative to linear chains with the same weight average molecular weight Mw and for the same temperature is useful, for example, for an accelerated fabrication involving extrusion, injection molding, film blowing, and the like. Conveniently, the polymers coupled in accordance with the practice of the invention also exhibit a broader temperature scale for thermoforming relative to the starting material without poly (sulfonyl azide), a higher Te crystallization temperature when l since melting, which is useful for controlling transparency in film applications in relation to the starting material without poly (sulfonyl azide), or a combination thereof. Accordingly, the modified rheology resins of the invention conveniently have high melt viscosities at shear and extensional flow rates required for applications involving drag flow, which are, for example, key to reducing subsidence in thermoforming, while that their viscosities drop dramatically to those of unmodified resins because of the easy flow required at high shear rates for fast film production. Both characteristics are typically observed when introducing long chain branches or similar structures into a polymer. Melt strength is measured under uniaxial conditions of extensional flow under isothermal conditions. The linear chains of isotactic polypropylene are not stressed harder for all the molecular weight reported in the literature. In contrast, the chain-coupled isotactic polypropylene chains are hard-hardened strongly as indicated by an increase in viscosity? E + by a factor of 10-100. Stress hardening in the uniaxial extensional flow is a measure used in the art, such as in the Montell Patents (US 5,554,668; European 0190889) which disclose a high melt strength for polymers obtained in alternative routes to polypropylene. linear. The characterization of a high melt strength resin commercially available from Montell Polyolefins, Inc. under the trade designation Profax PF 814, shows a dependence on the tensile stress growth coefficient? E + over time and the tension index ea 175 ° C. Stress hardening, indicated by? E + > 3 |? |, Is observed for t > 1 second to all the tension indices illustrated. Similar levels (1 to 2 orders of magnitude) of the strain hardening are produced with the chain-coupled resins according to the practice of the invention. Only one fracture failure was observed in both cases. The tensile stress growth coefficient? E + is a measure of the resistance of a fluid or semifluid to the uniaxial extensional flow, and is calculated from the stress and tensile measurements of a thermoplastic melt, when subjected to tensile stress at a constant index and temperature, for example, by the procedure described by J. Meissner in Proc Xllth International Congress on Rheology, Quebec, Canada, August 1996, pages 7-10, and by J. Meissner and J. Hostettler, Rheol. Acta, 33, 1-21 (1994). A commercial instrument for measurements is the Elongation Rhetorometer for Mergers (RME) commercially available from Rheometric Scientific. The dynamic shear viscosity coefficient? * Is a measure of the resistance of a fluid or semifluid to the shear flow, and is calculated from the stress and shear rate measurements of a thermoplastic melt, when subjected to to oscillatory shear stress of small amplitude, at constant voltage amplitude and temperatures, for example, using a parallel plate geometry in a Dynamic Mechanical Spectrometer II commercially available from Rheometric Scientific. Measurements of shear viscosity are within the skill of the art, for example, as described by R. Hingmann and B.L. Marczinke, J. Rheol. 38 (3), 573-87, 1994. The dependence of the magnitude |? * | of the dynamic shear viscosity on the angular frequency w is often used to measure the dependence of shear viscosity of continuous state n (?) on the shear rate?. The relationship is known in the art as the Cox-Merz rule (W.P. Cox and E.H. Merz, J. Polvm.Sci. 28: 619, 1958), and is applicable to many types of flexible polymer chains, as taught by J.M. Dealy and K.F. Wissbrun at Melt Rheology and its Role in Plastics Processing, Chapman & amp;; Hall, NY, 1995, pages 173-5. When the dependency of |? * | on w for a set of isotactic polypropylene materials before and after the chain coupling by practicing the invention to selected levels, the viscosities |? * | observed at a low w, conveniently rise by a factor of 100, after chain coupling. In contrast, the viscosities |? * | observed at a high w are relative measures of n (?) and high?, and are weakly sensitive to chain coupling. As a result, the coupled chain materials have the highest melt viscosities required for applications involving drag flows, to reduce collapse in thermoforming, for example, while their viscosities drop dramatically to those of non-coupled materials. an easy flow required at high rates of shear to make the film. The decrease in melt viscosity with a higher shear rate is called shear thinning.

The coupled chain materials tear thinner more strongly than non-coupled materials. The thermoforming of many semicrystalline materials, such as isotactic polypropylene, is commonly performed at temperatures between the softening and melting points, termed a thermoforming window. In this temperature scale, the pull modules of the solid bars fall deeply when heated, and the shear viscosity of the molten discs rises rapidly when cooled. This phenomenon is known in the art, for example, as discussed by J.L. Throne, Technology of Thermoforming, chapters 2 and 4, Hanser, N.Y., 1996, which includes examples of various materials. The thermoforming window can be only a few degrees Celsius, for an isotactic polypropylene sample, without chain coupling. In contrast, the coupled chain materials have wider windows (e.g., 4 to 15 ° C), and the width of the window varies with the level of chain coupling. The higher melt viscosities and the resistances of the coupled chain isotactic polypropylene make it possible to extend the processing window to the melting temperatures. The coupled chain isotactic polypropylene materials crystallize at higher temperatures (Te) when cooled from the melt, than their uncoupled (linear) starting materials. A deep elevation in the shear viscosity with cooling indicates the crystallization of the resin. The chain coupling increases the Tc as much as 25 ° C. The propylene polymers coupled in accordance with the practice of the invention, are particularly useful for making large articles, due to the reduced sinking on heating, compared to the polymer of the same composition that has not been coupled. These large parts include appliance parts, including refrigerator liner parts (e.g., door liners), automotive parts such as peak bed liners, and containers such as tubs. The following examples are to illustrate this invention, and not to limit it. The proportions, parts, and percentages are by weight, unless otherwise reported. The examples (Ej) of the invention are designated numerically, while the comparative samples (C.S.) are designated alphabetically, and are not examples of the invention. In these examples, and as hereinafter referred to, gel permeation chromatography (GPC) was conducted according to the following procedure: The analysis was performed on a Waters high temperature instrument at 150 ° C. Sample Preparation: 15 ± 1.0 milligrams of the sample were dissolved in 13.0 milliliters of TCB (trichlorobenzene) containing 300 ppm w / w (w / w) of 2,6-d (tertiary butyl) 4-methylphenol commercially available in Shell Chemical Company, under the commercial designation lonol. The solutions were stirred at 160 ° C for 2 hours. The hot solutions were filtered using a 0.5 micron stainless steel filter. Pump: Flow rate of 1.1 milliliters / minute nominal, at a temperature of 60 ° C. Eluent: 1, 2,4-trichlorobenzene of Fisher's high performance liquid chromatography grade, with 200 ppm w / w lonol. Injector: Injection of 150 microliters, at a temperature of 135 ° C. Columns: 3 columns commercially available from Polymer Laboratories, under the commercial designations Mixed B, 10 microns, SN 10M-Mixed B-87-130, 87-132, and 103-37, heated at 135 ° C.

Detection: Refraction index detector with a sensitivity of 32, and a scale factor of 10.

Data system: Commercially available at Polymer Laboratories, under the trade designation Caliber GPC / SEC, version 6.0.

Calibration: A universal polystyrene / polypropylene calibration was performed using polystyrene standards of a narrow molecular weight distribution of Polymer Laboratories with lonol as the flow marker. PS k = 12.6e-5 a = 0.702 Polypropylene k = 14.2e-5 a = 0.746 The bis (sulfonyl azide) s were prepared by the reaction of sodium azide with the bis (sulfonyl chloride) s, and all bis (sulfonyl chloride) s were commercially available. Two sets of conditions were used for the preparation of the sulfonyl azides. In the first, an aqueous solution of sodium azide was added to an acetone solution of the bis (sulfonyl chloride), and the product was isolated by precipitation with an excess of water. This protocol was used for all azides, except oxy-bis ((4-sulfonylazide) benzene) and 1,3-bis (sulfonyl azide) benzene which did not precipitate well from aqueous acetone. For these compounds, solid sodium azide was added to the corresponding acetone bis (sulfonyl chloride) solution.

Example 1: Preparation of long coupled chain isotactic polypropylene A sample of 1000 grams of isotactic polypropylene granules (commercially available from Montell NA, under the trade designation Montell Profax 6231, melt flow rate (MFR) = 20), was coated uniformly with 1 gram of silicon oil, by adding the silicon oil to the granules, and then with tumbling the mixture for 1 hour. To this mixture was added 1 gram of oxy-bis ([4-sulfonylazido] benzene) (BSA) in solid powder, and 0.5 gram of Irganox B-225 thermal stabilizer (Ciba-Geigy) followed by tumbling for an additional 1 hour, to uniformly coat the polypropylene granules with the solid powder. The granules were fed to a 20 millimeter Welding Engineers twin screw extruder working at 200 rpm, with the following temperature profile: The isotactic polypropylene product exiting the die of the extruder was cooled in a water bath and granulated in a chopper. The product was characterized using dynamic mechanical spectroscopy (DMS), differential scanning calorimetry (DSC), and gel permeation chromatography (GPC), all in accordance with manufacturers' instructions.

Properties of the PP of Partida Properties of the PP Coupled Mw = 234,500 g / mol Mw = 304,700 g / mol Mw / Mn = 7.9 Mw / Mn = 10.8 Tm = 170 ° C Tm = 170 ° C Te = 110 ° C Te = 128 ° C? * At 0.10 rad / sec. = 17.679 Poise? * At 0.10 rad / sec = 46.025 Poise = 4603 Pa / s? * At 100 rad / sec. = 2476 Poise? * At 100 rad / sec. = 1827 Poise = 183 Pa / s The profiling of the temperature of this invention allowed the bis-sulfonylazide compound (BSA) (m.p. = 101 ° C) to mix intimately with the isotactic polypropylene softened in Zones 1 and 2 of the extruder. Although the set temperature was 170 ° C in the first Zone, it was observed that the polymer temperature was lower than the melting temperature of the polymer. The fusion was observed in the second zone. The liquid bis-sulfonyl azide compound was well dispersed in the isotactic polypropylene in this way as the melting temperature reached that required to generate a significant concentration of active nitrene species (approximately 170 ° C). This resulted in a more homogeneous reaction with isotactic polypropylene than would the mixture at or above the decomposition temperature of the sulfonyl azide, which would result in localized regions in the isotactic polypropylene melt that would contain a high concentration of BSA, which could lead to gel formation.

Examples 2, 3, and 4: Demonstration of Long Chain Coupling The procedure of Example 1 for Examples 2, 3, and 4 was repeated, with the exception that the amounts of BSA were 0.250 weight percent, 0.060. percent by weight, and 0.125 percent by weight for Examples 2, 3, and 4, respectively. The direct evidence that the reaction products between the isotactic polypropylene and a bis-sulfonylazide, was that the coupled chain was derived from the characterization of the materials by gel permeation chromatography, using an intrinsic viscosity detector in accordance with the manufacturer's instructions. A branched polymer typically exhibits a lower intrinsic viscosity than a linear analog of the same molecular weight. The deviation of a linear viscosity response against molecular weight is typically observed for branched polymers.

Accordingly, chain coupling in accordance with the practice of the invention results in polymer chain structures that act in a manner similar to branched polymers, even when it is believed that the molecular structures are a little different. A visual comparison of the solution viscosity graphs (intrinsic) against the molecular weight for Examples 2, 3, and 4, derived from the reaction of increasing amounts of BSA with isotactic polypropylene of a melt flow rate of 20, comparing with the linear isotactic polypropylene starting material, it shows a negative linearity deviation with increasing molecular weight, and was a clear indication of the presence of the chain coupling inside these samples. From the raw data for a plot of the molecular weight record against the intrinsic viscosity record, selected by molecular weight of the record, the negative linearity deviation was evident.

In the Table of Example 1, PP means isotactic polypropylene. The graph of the data, such as that of the Table of Example 1, and other tables herein, is within the skill of the art, and is illustrated in the U.S. Patent Application Pending Number of Series 60/057713, filed on August 27, 1997.

Comparative Samples A and B. and Figure 1: To illustrate the effect of mixing at a decomposition temperature, an experiment was run on a static mixing device (commercially available Haaker mixer) at a fixed temperature (210 ° C), using the same starting materials in the same concentrations as in Example 1. The change in the rheological properties measured by dynamic mechanical spectroscopy at 200 ° C of the resulting coupled chain isotactic polypropylene is shown in Figure 1. The degree of rheological change is greater for the material produced using the extruder and a temperature profile (Example 1, designated J) against the batch mixer operating at a fixed temperature (CS A designated as H) corresponding to the methods of the prior art. The polypropylene of the starting material is included in Figure 1 for a comparison (C.S. B), and is labeled as B. In Example 1, the poly (sulfonyl azide) was mixed with the starting polymer in the softened or molten phase. It was evident that the practice of the invention results in a material having a higher viscosity at a low shear stress, and a lower viscosity at a high shear stress, than any of the Comparative Samples.

Examples 5-12 and Comparative Samples C-E: Illustrate the Advantages of the Lower Molecular Weight Particle Polymer The procedure of Example 1 was repeated, with the exception that the types and amounts of the starting materials were as shown in the Table of Example 5: Where the isotactic polypropylene of a melt flow rate of 35 is commercially available from Montell, NA, under the trade designation Profax PD-701, isotactic polypropylene melt flow rate of 20 is commercially available from Montell NA, under the commercial designation Profax 6231, and the isotactic polypropylene melt flow rate of 12 is commercially available in Montell, NA, under the trade designation Profax 6323. The Table of Example 5 illustrates the advantages of using a lower starting material molecular weight, because a larger range of coupled chain polypropylene products was possible, starting with an isotactic polypropylene with a melt flow rate of 35 (molecular weight of approximately 186,000), compared to an isotactic polypropylene of a flow rate of fusion of 12 (molecular weight of approximately 278,000). It can be seen that, using a lower molecular weight isotactic polypropylene as the starting material, a range of coupled chain isotactic polypropylene products is provided, with melt flow rates of 2 to 35, which remain easy to maintain. processing, in contrast to the start, with an isotactic polypropylene of a high molecular weight that achieves a less desirable low melt flow rate (eg, 1-2), even after the reaction with a relatively small amount of BSA.

Example 13 and Comparative Sample F: Improved mixtures of isotactic polypropylene / polyolefin elastomer For the example 13,700 grams of isotactic polypropylene granules (commercially available from Montell NA, under the trade designation 6231, melt flow rate = 20), and 300 grams of ethylene / octene elastomer granules (commercially available from The Dow Chemical Company, under the trade designation ENGAGE 8200), were uniformly coated with 1 gram of silicon oil, by the addition of silicon oil to the granules, and then the mixture was turned over for 1 hour. To this mixture was added 1 gram oxy-bis ([4-sulfonylazido] benzene) (BSA) in solid powder, and 0.5 gram of thermal stabilizer commercially available in Ciba Geigy under the trade designation Irganox B-225, followed by tumbling during 1 additional hour to uniformly coat the polypropylene granules with the solid powder. The granules were fed to a 20 millimeter twin screw extruder, commercially available from Welding Engineers, working at 200 rpm, with the following temperature profile: Table of Example 13A The product of TPO (thermoplastic polyolefin) exiting the die of the extruder was cooled in a water bath and granulated in a chopper. In addition, a control sample (C.S.F) that did not contain BSA coupling agent was also composed, under identical conditions. Both materials were injection molded into tensile and impact test samples in an injection molder commercially available from Boy Inc. under the trade designation Boy 30M. The physical properties of these samples were then tested using standard ASTM procedures as designated in the Table: Table of Example 13B The most significant difference between these samples was the impact energy at -30 ° C, measured by MTS dart impact (ASTM D3763-93). The control (C.S.F) exhibited only a brittle failure, while the reactively coupled thermoplastic polyolefin (Example 13) was of a completely ductile character. The relative scattering can be seen from the transmission micrographs, which show that Example 13 has significantly smaller scattered phase particles, compared to (C.S. F). The images of the micrographs were analyzed using ware commercially available from Scion Corporation under the ware trade name ImagePC, to measure the average particle diameters of 0.23 microns for the dispersed phase in Example 13, and 0.57 microns for the dispersed phase in Comparative Sample F. This method for counting and measuring the average dimensions of the dispersed phase polymer particles is within the skill of the art. Electron micrographs and their interpretation are within the ability of the subject, as illustrated in the pending United States Patent Application Serial Number 60/057713, filed on August 27, 1997. The evidence for the formation of coupled chain structures came from the dynamic mechanical spectroscopy measurements of the reactive coupled thermoplastic polyolefin (Example 13) and the control (Comparative Sample F). As described above, the branched or coupled structures lead to higher viscosities at low shear stress, accompanied by a "tear thinning" at higher rates of shear stress. The reactive coupled thermoplastic polyolefin of Example 13 exhibited this behavior, as compared to the control mixture (C.S. F) of the linear materials. Viscosity and angular frequency were as measured by dynamic mechanical spectroscopy.

Example 14 Comparative Sample G: Materials of Thermoplastic Elastomer Two thermoplastic elastomer materials were prepared in a commercially available Haake mixer, at 200 ° C / 1 OOrpm / 5 minutes, with the following compositions: Table of Example 14A * an isotactic polypropylene of a melt flow rate of 35 commercially available in Montell under the trade designation Profax PD-701. ** an ethylene and octene elastomer commercially available from The Dow Chemical Company under the trade designation AFFINITY 8200. The product of thermoplastic elastomer materials were compression molded in a commercially available heated compression molding press available in Tetrahedron, under the trade designation model 14 at 200 ° C, and analyzed by transmission electron microscopy, to characterize the dispersion of isotactic polypropylene and dynamic mechanical spectroscopy (temperature sweep), to determine the behavior of the Module against temperature. A better voltage transfer between the phases of Example 14 on Comparative Sample G was evidenced by the response of the material module as a function of temperature.

Table of Example 14B The thermoplastic elastomer with control (C.S. G) falls significantly in the module above 50 ° C, while the thermoplastic elastomer reactively coupled (Example 14) maintains two orders of magnitude plus modulus at 150 ° C. Accordingly, the potential end-use temperature of the reactive coupled thermoplastic elastomer would be significantly greater as a result of this difference in performance. The elastic and viscous properties of polymeric materials as a function of temperature and frequency, can provide valuable information relevant to their manufacture and end use. As such, these tests are useful for comparing different polymeric materials. For example, a higher elastic modulus at a given temperature will result in greater rigidity in an equivalent part. Also, for example, a lower glass to glass transition temperature will generally result in a better hardness at low temperature. The tests used to generate the data of Table 14B, were made on rectangular polymer bars (approximately 6.35 cm x 1.27 cm by 0.3175 cm.), Using a dynamic mechanical spectrometer. The specific equipment used measures the torque signal at one end of the sample, in response to a torsional voltage that varies sinusoidally, which was applied at the other end (dynamic mechanical spectrometer model RDS-IIE equipped with a transducer rebalancing medium range strength, and with an environment chamber for high temperature operation manufactured by Rheometrics, Inc., Piscataway, NJ). The instrument also determines the phase angle between the output of the torque and the voltage input signals. The magnitude of tension was related to the magnitude of the torque by means of a proportionality factor, which was a function of the dimensions of the sample. Knowing the phase angle between the tension and the tension, the tension signal can be decomposed into its components in phase and out of phase with the traction. The responses in phase and out of phase correspond to the elastic and viscous responses of the material, respectively. The dynamic shear storing modulus (G ') was calculated as the proportion of the in-phase portion of the tensile stress, and the dynamic shear loss modulus (G ") as the proportion of the portion outside the shear force. phase of tensile stress The final outputs of the instrument were the storage of dynamic shear stress and the loss of modules, G 'and G ", which were the elastic and viscous responses, respectively. The G'VG 'ratio is known as the loss tangent, or tan d. This test procedure gives values for G ', G ", the tangent of loss at different temperatures, and the fixed torsion frequency.Another general information about the measurement of the dynamic mechanical properties and its phenomenology and interpretation at the molecular level, can be find in conventional texts (for example, JD Ferry, "Vlscoelastic Properties of Polymers", 3rd edition, published by John Wiley and Sons).

Again, the Transmission Electron Microscope shows that a much finer dispersion of the practice of the present invention results.

Examples 15 and 16: Coupling at Two Temperatures For Example 15, 200 grams of an isotactic polypropylene of a melt flow rate of 20, commercially available from Montell Polyolefins under the trade designation 6231, was charged into a mixer's container. Haake fusion operating at 100 rpm with a set temperature of 170 ° C, together with 0.10 grams of stabilizer commercially available from Ciba Geigy Corporation, under the trade designation Irganox B-225. After melting the polymer, the melting temperature (temperature of the molten polymer) was 200 ° C, at which point, 0.20 grams of oxy-bis (4-sulfonylazidobenzene) was added, and the coupling reaction was allowed to proceed during 5 minutes. The apparatus was cooled, and the polymer was removed. For the comparative sample GG, a similar experiment was conducted under the same conditions, with the exception that an established temperature of 200 ° C was used, which resulted in a melting temperature of 240 ° C, once it had melted completely the polymer. In this second case (CS GG), at the highest melting temperature, the polymer did not provide a significant (sharp) increase in torque, which would indicate an increase in molecular weight (and consequently, in viscosity). of fusion) through chain coupling.

Example 17 and Comparative Sample H: Practice of the Invention using Styrenic Materials: (A) For the Example 17.40 grams of the polystyrene commercially available from The Dow Chemical Company under the trade designation Styron ™ 615, they were heated and mixed in a Brabender reactor. Plasticorder at 200 ° C, at 80 rpm, followed by the addition of 0.10 grams of oxy-bis [(4-sulfonylazido) benzene. The mixture was allowed to react in the reactor for 5 minutes, and then it was removed and analyzed by dynamic mechanical spectroscopy (DMS), and gel permeation chromatography (GPC). A control sample (C.S.H) was also run in the same manner, only without the poly (sulfonyl azide). The dynamic mechanical spectroscopy data indicate an increase in the low shear melt viscosity, which indicates the chain coupling in the example (Example 17) which reacted with poly (sulfonyl azide), compared to the C.S. control. H. The gel permeation chromatography data also support the polystyrene chain coupling, as a consequence of the reaction with the poly (sulfonyl azide) compound, as evidenced by the shoulder on the high molecular weight side of the curve against the control sample. The molecular weight measured for Example 17 was 242,300, with an Mw / Mn of 2.58, and the molecular weight of C.S. H was 199,100, with an Mw / Mn of 2.35. (B) For example 18, a similar experiment was performed, wherein a mixture of 20 grams of polystyrene (same as the starting material for Example 17), and 20 grams of ethylene / octene polyolefin elastomer commercially available in The Dow Chemical Company under the trade designation POE, AFFINITY EG8150, were melted and mixed in a Brabender Plasticorder reactor at 200 ° C, and at 80 rpm. Followed by the addition of 0.10 grams of oxy-bis (4-sulfonylazido) benzene. The mixture was allowed to mix and react for 5 minutes, and then it was stirred and allowed to cool. A control test (C.S. J) was performed in exactly the same way, only without the poly (sulfonyl azide). Then both samples were compression molded into small plates using a Tetrahedron Model 14 compression moulder at 200 ° C. The morphology of the samples was then characterized using transmission electron microscopy, which showed a much finer phase dispersion in the practice of the invention (Example 18) than in C.S. J. These data indicate a finer dispersion of the polystyrene and POE in Example 18, when the mixture is allowed to react with poly (sulfonyl azide), comparing with C.S. J, the control sample, which has a very low dispersion of polystyrene and POE, and poor interfacial adhesion between the materials. The differential scanning calorimetry curves of a polypropylene treated in accordance with the practice of the invention, a commercial propylene homopolymer, and a commercial propylene / ethylene random copolymer, show the peak at the decomposition temperature of the oxybis (4). sulphonylazidobenzene), which is at 186 ° C, and the initial softening at melting temperatures of a typical isotactic polypropylene at 154 to 158 ° C of a propylene random copolymer, which is 132-154 ° C.

Example 19: Illustration of Partially Fused Polyolefin Intimately Mixed with Poly (sulfonilazide) Prior to Actual Reaction Among Them: A 11.3 kilogram polypropylene sample commercially available from Montell Polyolefins Inc., under the trade designation Profax 6231, was coated with 100 grams of silicon oil, and it was turned for 2 hours, to evenly distribute the oil on the polypropylene granules. To this mixture, 12.7 grams of oxy-bis were added (sulfonylazidobenzene), and 10.0 grams of stabilizer commercially available from Ciba Geigy under the commercial designation of powders B-225. The mixture was tumbled for 2 hours to uniformly coat the powders on the surface of the polypropylene granules. This mixture was extruded in a 30 mm WP twin screw extruder commercially available from Warner-Pfliederer, working at 100 rpm, with a temperature profile (set temperature) of 170 ° C in the feed zone, up to 180 ° C in the final zone before the die. The melting temperature (temperature of the polymer stream) observed just before the die was 213 ° C, indicating that the temperature of the melt had increased significantly, due to the mechanical shear mixing of the polyolefin , in addition to the heat supplied by the extruder zones. Accordingly, the polymer reached a temperature profile of 170 ° C in the feed zone (without additional shear heating) to 213 ° C near the end of the extruder. The extruder was rapidly cooled by circulating large volumes of cold water through the different zones of the extruder (as allowed by the equipment design), to quench the melt in, and then opened to allow the samples to be taken from different positions along the screw of the extruder, for the analysis of molecular weight and subsequent rheological. The Table of Example 19A shows that the molecular weight of the polymer increased a little, going from 60.96 to 76.2 centimeters (from the feed gate), and more from 76.2 centimeters to 91.44 centimeters, and the molecular weight distribution increased a little. up to 76.2 centimeters, but very quickly between 76.2 centimeters and 91.44 centimeters.

Table of Example 19A The Table of Example 19B shows the viscosity at different annular frequencies of each sample in Table F17: At lower frequencies, the material from 48.26 centimeters from the feed gate is much less viscous than each successive sample with the material extruded from the given much more viscous than in the previous positions. The differences in viscosity narrow very significantly to 100 rads.

Table of Example 19B The ability to soften the polymer prior to the actual reaction was improved by using a polypropylene of lower molecular weight, ie, a molecular weight of less than 275,000. It is well known in the art that lower molecular weight polymers soften and flow at a given temperature more readily than polymers of higher relative molecular weight.

Example 20: Advantages of the Chain Coupling in the Manufacturing The iPP sample prepared as in Example 19, was extruded into a sheet (33.02 centimeters wide by 0.254 centimeters thick) in a Sterling sheet extrusion line, and then thermoformed in an AAA vacuum thermoformer in containers. rectangular (20.32 centimeters by 25.4 centimeters), at a stretch ratio of 4: 1. As a control (C.S. K), a commercial linear polypropylene commercially available from Montell Poiyolefins Inc. under the trade designation Montell S30S, which was typically used in thermoforming, was also tested. In the same manner, a commercial branched iPP, commercially available from Montell Poiyolefins Inc., was also extruded under the trade designation Montell PF814, which is believed to be prepared as described in US Pat. Nos. 4,916,198.; US 5,414,027 and US 5,554,668 (all assigned to Montell), in a sheet, and thermoformed (C.S. K '). All samples were tested to determine the temperature scale under which acceptable parts could be made without excessive sheet sinking (ie, acceptable melt strength). The following table shows that the coupled polypropylene prepared by the practice of this invention gave superior performance in the thermoforming application.

Table of Example 20 It is known in the art that the ability of a thermoforming resin to resist sinking over as wide a range of temperature as possible is highly desirable. This minimizes the effect of the variations by the processing temperature on the quality of the thermoformed parts produced.

Examples 21 and 22: Comparison of Start Materials of Narrow Molecular Weight and Wider Molecular Weight For Example 21.4 grams of polypropylene of a narrow molecular weight distribution (commercially available from Exxon Chemical Company under the trade designation Achieve 3904; Molecular Weight = 185,500), were placed in a heated vessel of a Brabender Plasticorder, and mixed melted at 200 ° C. When the polymer was completely melted, 0.05 grams of stabilizer (commercially available from Ciba Geigy Inc., under the trade designation Irganox B-225), and 0.10 grams of oxybis (4-sulfonylazidobenzene), were added to the polymer melt. , and mixing was continued at 100 rpm for 5 minutes at 200 ° C. The polymer was then removed from the container of the Brabender mixer, and allowed to cool. He gave a molecular weight = 294,200. The polypropylene material of a conventional broad molecular weight distribution (commercially available from Montell Poiyolefins Inc. under the trade designation Profax 6231, molecular weight = 239,000) was coupled by the same procedure to form Example 22. This sample had a molecular weight = 292,000. The starting polymer and the product of the previous Example were characterized by calorimetry in differential scanning equipment (commercially available from DuPont Instruments under the trade designation 2910 DSC), to determine the melting and crystallization behavior of the materials. It was observed that the polypropylene of a narrow molecular weight distribution (Example 21) demonstrated a significantly broader melting point relative to the polypropylene starting material of a narrow molecular weight distribution not treated with bis-azide. The result was unexpected in relation to similar experiments on polypropylene of a conventional broad molecular weight distribution (Example 22) treated in a similar manner. The broader melting point polypropylenes were useful in thermoforming, blow molding, foaming, and film applications. The crystalline melting point extension serves to expand the thermal processing temperature window for the material.

Example 23: Illustration of the effect of residual time on molecular weight increase (and therefore, coupling) The following experiment was performed on a Werner-Pfliederer twin screw extruder of 30 millimeters (as described in Example 19), working at 100 rpm, using polypropylene of a melt flow rate of 35 (commercially available from Montell Poiyolefins Inc. under the trade designation Montell PD701), as the power supply, and 1250 ppm bis-sulfonylazide diphenyl oxide ( DPO-BSA). The residence time in the extruder was varied over the range indicated in the Table of Example 23, changing the position of the screw in relation to the barrel, which created a plug flow area in front of the die. The melting temperature of the polymer was varied by changing the set temperatures of the extruder zone.

Table of Example 23 It can be seen that the residence times measured in minutes were necessary to provide ample time for the coupling chemistry to run to completion, even when the shorter times were effective to achieve lower coupling quantities.

Example 24: Another indication of the effect of the reaction time on molecular weight increase (and consequently coupling) In the following experiment, 40 grams of polypropylene homopolymer of a melt flow rate of 35 (commercially available in Montell Poiyolefins under the commercial designation Montell PD701) were heated in a Haake mixer at 200 or 230 ° C, and 1,500 ppm and DPO-BSA was added. A small amount of the polymer was removed from the reaction, and quenched with dry ice at regular time intervals. These samples were then analyzed by gel permeation chromatography, to follow the molecular weight of the polypropylene as a function of time. An increase in molecular weight was observed, reaching a maximum. The results are tabulated in the Table of Example 24.

Table of Example 24 This was followed by a decrease in molecular weight when the coupling reaction was terminated, and thermal degradation of the polypropylene took place. When a higher molecular weight is desired, it is preferred to allow the mixture of the polymer and poly (sulfonyl azide) to remain at least at a temperature above the decomposition temperature, for a time sufficient to reach the maximum or near maximal molecular weight increase. , but to avoid exposure to that temperature for a sufficient time to result in sufficient degradation resulting in low molecular weight.

Example 25: Illustration of the effect of reaction time on the remaining concentration of poIKsulfonilazide) In this experiment, 40 grams of atactic polypropylene prepared using (? 5 -tetra methylcyclopentadienylbutyl-tertiary-amide-dimethylsilane) titanium (? 4-1, 3- pentadiene) according to the teachings of U.S. Patent No. US 5,470,993, as a catalyst, were mixed with 1 weight percent DPO-BSA in a Haake mixer at 100 ° C for 2 minutes. Then this material was analyzed by calorimetry, and by differential scanning calorimetry, to determine the kinetics of the reaction, measured by the concentration of unreacted DPO-BSA, divided by the initial concentration of DPO-BSA ([BSA] / [BSA] ] 0) as a function of time. The results are tabulated in Table 25.

Table of Example 25 From these data, it is evident that the time for BSA to react is a function of temperature, and that for temperatures of 200 to 230 ° C, the residence time to complete the decomposition of BSA was at least 2 minutes .

Examples 26-31, and Comparative Samples M and N: Illustration of a Wide Range of Part Formation Temperatures for Suitable Materials A series of PP samples coupled to the 30-millimeter Werner Pfleiderer twin-screw extruder described in the Example were prepared. 19, working at 100 rpm, with a melting temperature of approximately 220 ° C. Then these resins were extruded into a sheet 35.56 centimeters wide and 0.3175 centimeters thick, along with two linear polypropylene control materials, such as C.S. M, a polypropylene resin of a melt flow rate of 0.6, commercially available from Montell Poiyolefins under the trade designation D50S, and a C.S. N, a polypropylene resin of a melt flow rate of 2.4, commercially available from BASF Corp., under the trade designation 1102 (melt flow rate = 0.6 and 2.4, respectively). The sections of the sheet were thermoformed as described in Example 20, at a stretch ratio of 3.5 to 1. The temperature scale on which parts of an acceptable quality could be thermoformed was then measured for each resin.

Tables of Example 26A PP Samples Coupled for Thermoforming of the invention were commercially available polypropylene resins The Dow Chemical Company under the commercial designations shown, ie, H700-12, H701-20, and H702-35.

Table of Example 26B Clearly, the coupled resins (Ex.26-Ex.31) demonstrated a much broader thermoforming window relative to a linear polypropylene control of a comparable melt flow rate (C.S. N). The linear polypropylene of C.S. M gave a large thermoforming window; however, this material was difficult to manufacture (extrude) in the sheet for thermoforming, due to its very high molecular weight, which caused it to require higher extrusion temperatures, a torque from the motor of the higher extruder, or a combination thereof, in order to become the sheet before thermoforming.

Examples 32-37 and Comparative Sample P-U: Illustration of the efficiency of the improved impact modification using coupling The procedure of Example 13 was repeated for the Examples 32-37 and the PU comparative samples, with the exception that the propylene polymer was commercially available from Montell North America under the trade designation Profax PD701, MFR 35 PP, and the elastomeric phase was a commercially available ethylene / octene copolymer in The Dow Chemical Company under the trade designation Engage 8100, and were used in the relative amounts indicated in the Table of Example 32. The Examples of the invention were each reacted with 1 gram of the oxy-bis ([4-sulfonylazido] benzene) (BSA); although the Comparative Samples were mixed with the other additives listed in Example 13, but not the BSA. The total impact energy was measured in accordance with the procedures of ASTM D3763-93, as mentioned in the Table: Table of Example 32: Efficiency by Coupling The data in the Table of Example 32 show that although the impact resistance was not improved when there were no two phases (eg 32 and C.S. P); it was improved by coupling in a thermoplastic polyolefin having a propylene polymer and an elastomer, on a thermoplastic polyolefin having the same constituents but without coupling. Accordingly, the efficiency of the impact modification with the coupling was improved according to the practice of the invention. The effect was particularly remarkable, since the improvement of impact by adding increasing elastomer, reaches a plain, such as between C.S. T and C.S. U at 30 and 35 weight percent elastomer, respectively, where little difference was seen without coupling, but more difference was seen with the coupling in Example 36 and Example 37. It can be seen that more elastomer is useful to achieve increased impact resistance in the coupled mixtures than in the non-coupling mixtures, in accordance with the practice of the invention.

Claims

CLAIMS 1. A process for the preparation of a modified rheology polyolefin, characterized by the steps of: (a) mixing at least one polyolefin with a rheology modifying amount of a poly (sulfonyl azide) at a temperature, referred to later in the present as a mixing temperature, which is at least the softening temperature of the polyolefin but less than the decomposition temperature of the poly (sulfonylazide) to form a substantially uniform mixture of polyolefin and poly (sulfonylazide); and (b) heating the substantially uniform mixture of a polyolefin and poly (sulfonylazide) at a temperature, hereinafter referred to as a reaction temperature, which is at least the decomposition temperature of the poly (sulfonyl azide).
2. The process of claim 1, wherein step (b) is presented at a temperature of at least 5 ° C above the mixing temperature and at least the peak decomposition temperature of the poly (sulfonyl azide) and wherein the mixture contains from 0.01 to 0.5% by weight of poly (sulfonyl azide).
3. The process of claim 1 or 2, wherein both steps (a) and (b) take place in the same container.
4. The process of claim 3, wherein the polyolefin is a propylene polymer.
The process of claim 1, 2 or 4, wherein both steps (a) and (b) take place in the same vessel and wherein the polyolefin comprises a propylene polymer having a molecular weight less than 275,000 and greater than 100,000 The process of claim 5, wherein there are at least three temperatures between 160 ° C and 230 ° C including the mixing and reaction temperatures, each temperature being different from the others by at least 5 ° C, being at least a reaction temperature at least 5 ° C above the decomposition temperature of the poly (sulfonyl azide), and at least one mixing temperature being at least 5 ° C above the softening temperature of the polyolefin and at least 5 ° C below the decomposition temperature of the poly (sulfonyl azide), and the three temperatures occurring in a single vessel, and wherein step (b) takes place at a temperature (TR) of at least 200 ° C to 230 ° C , for a period of time (tr) corresponding to at least 4 minutes at 200 ° C and at least 2 minutes at a temperature of at least 230 ° C, this time corresponding to the equation tr = 4 (TR -200) * 0.1 .
The process of any of claims 1 to 6, wherein at least one poly (sulfonyl azide) has a structure
XRX, wherein each X is SO2N3, and R represents a hydrocarbyl, hydrocarbyl ether, or silicon-containing, unsubstid or inertly substid group, the poly (sulfonyl azide) has at least 3 to 50 carbon atoms, silicon or oxygen between the sulfonyl azide atoms, and R includes at least one aryl group between the sulfonyl groups.
8. A process for the preparation of a modified rheology polyolefin, characterized by a step of (a) heating a substantially uniform mixture of a polyolefin and a rheology modifying amount of a poly (sulfonylazide) at a temperature, referred to later in the present as a reaction temperature, which is at least the decomposition temperature of the poly (sulfonyl azide), and wherein the polyolefin comprises a mixture of at least one non-elastomeric polymer, and at least one elastomeric polymer, wherein the polymer does not Elastomeric is a propylene polymer, wherein the elastomeric polymer has at least 40 weight percent ethylene repeating units; and wherein the weight ratio of the non-elastomeric polymer to the elastomeric polymer is 0.75 to 0.15, and wherein the poly (sulfonyl azide) is used in an amount sufficient to increase the impact strength of the mixture, or to increase the dispersion of the at least one polymer of the mixture.
9. A process for the preparation of a modified rheology polyolefin, characterized by a step of (a) heating a substantially uniform mixture of a polyolefin and a rheology modifying amount of a poly (sulfonyl azide) at a temperature, hereinafter referred to as a reaction temperature, which is at least the temperature of decomposition of the poly (sulfonyl azide), and wherein the polyolefin comprises a propylene polymer having a molecular weight of less than 25,000.
10. A composition made by the process of any of claims 1 to 9.
11. A mixture composition comprising any composition of any of claims 1 to 10, with at least one additional polymer.
The use of any composition of any of claims 10 to 11, in any process of thermoforming, injection molding, extrusion, extrusion coating, casting, blow molding, foaming, film forming, or blowing.
13. An article that is thermoformed, injection molded, extruded, emptied, blow molded, blown, foamed, or molded articles of any composition of any of claims 10-11, or a product of the use of the claim 12.
14. An article that is a foam, film, or fiber of any composition of any of claims 10 or 11, or a product of the use of claim 12.
15. The article of claim 13 or 14, which is a coating of peak bed or a part of refrigerator, tub or container.