| PATENT NUMBER | This data is not available for free |
| PATENT GRANT DATE | January 5, 1993 |
| PATENT TITLE |
Elastomer-plastic blends |
| PATENT ABSTRACT | The present invention relates to compositions comprising at least one elastomer and at least one plastic. The composition can be produced by preparing the elastomer and then blending it with the plastic. The composition can be subjected to an additional step of curing |
| PATENT INVENTORS | This data is not available for free |
| PATENT ASSIGNEE | This data is not available for free |
| PATENT FILE DATE | August 21, 1990 |
| PATENT REFERENCES CITED |
Abstract of JP60072948-Japan Syn. Rubber-Apr. 1985. Ferdinand C. Stehling, Terry Huff, C. Stanely Speed, and G. Wissler, Journal of Applied Polymer Science, vol. 26, "Structure and Properties of Rubber-Modified Polypropylene Impact Blends," John Wiley & Sons, Inc. (1981), pp. 2693-2711. Natta et al., "Polyolefin Elastomers" pp. 1583-1668. Shih et al., "The Effect of Molecular Weight and Molecular Weight Distribution on the Non-Newtonian Behavior of Ethylene Propylene Diene Polymers" Tables II and III |
| PATENT PARENT CASE TEXT | This data is not available for free |
| PATENT CLAIMS |
What is claimed is: 1. A composition comprising: (a) at least one elastomer copolymer comprising ethylene and at least one other alpha olefin, having a weight average molecular weight of at least 20,000, and at least one of M.sub.w /M.sub.n less than 2 and M.sub.z /M.sub.w less than 1.8, wherein at least two portions of essentially each copolymer chain of said copolymer, each portion comprising at least 5 wt.% of the chain, differ in composition from one another by at least about 5 wt.% ethylene; (b) at least one plastic composition; and (c) at least one copolymer, in an amount equal to approximately 80 wt.% or less of the composition, comprising a plurality of Ziegler-Natta catalyzed ethylene alpha olefin polymer chains, substantially each of said chains being end capped with at least one functional group-containing unit which is otherwise essentially absent from said copolymer chains, said functional group being incorporated as a polymer unit selected from the group consisting of: ##STR7## the monomers thereof, and the mixtures thereof; wherein R.sub.1 through R.sub.4 are hydrocarbons with 1-30 carbon atoms selected from the group consisting of saturated or unsaturated, branched or unbranched, aliphatic, aromatic, cyclic, or polycyclic hydrocarbons, wherein R.sub.5 is the same as R.sub.4 but may additionally be hydrogen; and wherein x=1-10,000. 2. A composition comprising: (a) at least one elastomer copolymer comprising ethylene and at least one other alpha olefin, having a weight average molecular weight of at least 20,000, and at least one of M.sub.w /M.sub.n less than 2 and M.sub.z /M.sub.w less than 1.8, wherein at least two portions of essentially each copolymer chain of said copolymer, each portion comprising at least 5 wt.% of the chain, differ in composition from one another by at least about 5 wt.% ethylene; (b) at least one plastic composition; and (c) at least one copolymer, in an amount equal to 80 wt.% or less of the composition, comprising a plurality of copolymer chains, substantially each of said chains being a Ziegler-Natta catalyzed ethylene alpha olefin polymer chain end capped with at least one functional group-containing unit which is otherwise essentially absent from said polymer chain. 3. The composition as defined by claim 2 wherein said functional group is selected from the group consisting of: --CO.sub.2 H, --OH, --SH, --X, --C--C--benzene, --C--C--(pyridine), --SO.sub.2 H, SO.sub.3 H, and mixtures thereof, wherein X is a halide selected from the group consisting of fluorine, chlorine, bromine, and iodine. 4. The composition as defined by claim 2 wherein said functional group is selected from the group consisting of: isocyanates, urethanes, nitriles, aromatic ethers and aromatic carbonates. |
| PATENT DESCRIPTION |
BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to novel blends of elastomers and plastic compositions, and to novel processes for producing such blends. More specifically, the plastics which may be employed in these blends include polypropylenes, polyethylenes, including high density polyethenes, low density polyethylenes, and linear low density polyethylenes, polystyrenes, polyvinyl chlorides, polycarbonates, polyamides (nylons), polyesters, polyphenylene oxides, ethylene/methylacrylate copolymers, polybutylenes, polyvinyl acetates, ethylene/vinyl acetate copolymers, polymethyl methacrylates, acrylonitrile-butadiene-styrenes, acetals, alkyds, acrylics, polyethyl methacrylates, and heteroblock propylene-ethylene copolymers. Also suitable are mixtures of two or more of such plastic compositions, especially mixtures of polypropylene and polyethylene, including high density polyethylene (HDPE), low density polyethylene (LDPE), and linear low density polyethylene. Among the suitable polypropylenes are those disclosed in SMITH, Jr. (U.S. Pat. No. 4,059,651), HUFF (U.S. Pat. No. 4,087,485), FIELDING et al. (U.S. Pat. No. 4,087,486), HUFF (U.S. Pat. No. 4,221,882), SMITH, Jr. (U.S. Pat. No. 4,251,646), and ROSS (U.S. Pat. No. 4,375,531), the disclosures of which are hereby incorporated by reference thereto. Suitable elastomers for use in the blend are the compositions disclosed in related U.S. Pat. Nos. 4,540,753 (hereinafter COZEWITH et al); 4,716,207; 4,874,820; 4,786,697; 4,789,714; and 4,882,406, all issued to Cozewith et al. 2. Background Description of Relevant Materials For convenience, certain terms that are repeated throughout the present specification are defined below: a) Inter-CD defines the compositional variation, in terms of ethylene content, among polymer chains. It is expressed as the minimum deviation (analogous to a standard deviation) in terms of weight percent ethylene from the average ethylene composition for a given copolymer sample needed to include a given weight percent of the total copolymer sample which is obtained by excluding equal weight fractions from both ends of the distribution. The deviation need not be symmetrical. When expressed as a single number, for example 15% Inter-CD, it shall mean the larger of the positive or negative deviations. For example, for a Gaussian compositional distribution, 95.5% of the polymer is within 20 wt.% ethylene of the mean if the standard deviation is 10%. The Inter-CD for 95.5% wt.% of the polymer is 20 wt.% ethylene for such a sample. b) Intra-CD is the compositional variation, in terms of ethylene, within a copolymer chain. It is expressed as the minimum difference in weight (wt.) % ethylene that exists between two portions of a single copolymer chain, each portion comprising at least 5 weight % of the chain. c) Molecular weight distribution (MWD) is given a measure of the range of molecular weights within a given copolymer sample. It is characterized in terms of at least one of the ratios of weight average to number average molecular weight,M.sub.w /M.sub.n, and Z average to weight average molecular weight, M.sub.z /M.sub.w, where ##EQU1## Ni is the number of molecules of weight Mi. Ethylene-propylene copolymers, particularly elastomers, are important commercial products. Two basic types of ethylene-propylene copolymers are commercially available. Ethylene-propylene copolymers (EPM) are saturated compounds requiring vulcanization with free radical generators such as organic peroxides. Ethylene-propylene terpolymers (EPDM) contain a small amount of non-conjugated diolefin, such as dicyclopentadiene, 1,4-hexadiene, or ethylidene norbornene, which provides sufficient unsaturation to permit vulcanization with sulfur. Such polymers that include at least two monomers, i.e., EPM and EPDM, will hereinafter be collectively referred to as copolymers. These copolymers have outstanding resistance to weathering, good heat aging properties and the ability to be compounded with large quantities of fillers and plasticizers, resulting in low cost compounds which are particularly useful in automotive and industrial mechanical goods applications. Typical automotive uses are in tire sidewalls, inner tubes, radiator and heater hose, vacuum tubing, weather stripping and sponge doorseals, and as Viscosity Index (V.I.) improvers for lubricating oil compositions. Typical mechanical goods uses are for appliance, industrial and garden hoses, both molded and extruded sponge parts, gaskets and seals, and conveyor belt covers. These copolymers also find use in adhesives, appliance parts, as in hoses and gaskets, wire and cable, and plastics blending. The efficiency of peroxide curing depends on composition. As the ethylene level increases, it can be shown that the "chemical" crosslinks per peroxide molecule increase. Ethylene content also influences the rheological and processing properties, because crystallinity, which acts as physical crosslinks, can be introduced. The crystallinity present at very high ethylene contents may hinder processibility, and may make the cured product too "hard" at temperatures below the crystalline melting point to be useful as a rubber. As can be seen from the above, based on their respective properties, EPM and EPDM find many, varied uses. It is known that the properties of such copolymers which make them useful in a particular application are, in turn, determined by their composition and structure. For example, the ultimate properties of an EPM or EPDM copolymer are determined by such factors as composition, compositional distribution, sequence distribution, molecular weight, and molecular weight distribution (MWD). It is well known that the breadth of the MWD can be characterized by the ratios of various molecular weight averages. One of such averages is the ratio of weight average to number average molecular weight (M.sub.w /M.sub.n). Another of the ratios is the Z average molecular weight to weight average molecular weight (M.sub.z /M.sub.w). Copolymers of ethylene and at least one other alphaolefin monomer, including EPM and EPDM polymers, which are intramolecularly heterogeneous and intermolecularly homogenous, and which have a narrow MWD, characterized as at least one of M.sub.w /M.sub.n less than 2 and M.sub.z /M.sub.w less than 1.8, have improved properties in lubricating oil. Such copolymers are disclosed in COZEWITH et al., which is incorporated herein by reference. For convenience, such polymers are hereinafter referred to as narrow MWD copolymers. Copolymers having MWD with both M.sub.w /M.sub.n greater than or equal to 2 and M.sub.z /M.sub.w greater than or equal to 1.8 are hereinafter referred to as broad MWD copolymers. It is generally recognized that the cure rate and physical properties of copolymers of ethylene and at least one other alpha-olefin monomer are improved as MWD is narrowed. Narrow MWD polymers have superior cure and tensile strength characteristics over such polymers having broader MWD. However, the advantages in physical properties gained from having a narrow MWD are sometimes offset by the poorer processability of such materials. They are often difficult to extrude, mill, or calendar. Nevertheless, is certain instances the narrow MWD copolymer is advantageous in plastics blending. As to milling behavior of EPM or EPDM copolymers, this property varies radically with MWD Narrow MWD copolymers crumble on a mill, whereas broad MWD materials will band under conditions encountered in normal processing equipment. Broader MWD copolymer has a substantially lower viscosity than narrower MWD polymer of the same weight average molecular weight. Thus, there exists a continuing need for discovering polymers with unique properties and compositions. This is easily exemplified with reference to the area of blends of elastomers and plastics having various utilities. Plastic-elastomer blends comprising a discontinuous phase of the elastomer dispersed within a continuous phase of the plastic find various uses, such as in battery cases. For such blends, an intimate dispersion of the elastomer discontinuous phase within the plastic composition continuous phase is a desirable property. Blends comprising cocontinuous phases of plastic and elastomer tend to have greater impact strength than the pure plastic compositions, and are useful in such products as automobile bumpers. It is highly desirable in plastic-elastomer blends, particularly the continuous-discontinuous phases blends, to attain a higher Gardner impact strength without a corresponding lowering of knit line toughness or stiffness. U.S. Pat. No. 4,059,651 discloses a blend of 70-98 wt.% polypropylene, 2-30 wt.% EPDM elastomer, and halogenated phenol adehyde resin present in an amount of about 1-20 parts per 100 parts of elastomer. The elastomer is disclosed as containing about 40-80 wt.% ethylene and about 2-12 wt.% diene with the balance being propylene. The components are mixed by conventional techniques and heated at above the melting point of the propylene, e.g., 300.degree.-400.degree. F. Alternatively, the halogenated phenol aldehyde resin may first be mixed with the polypropylene at these same temperatures, with the elastomer mixed in thereafter. After the mixing and heating, the blend may be molded. U.S. Pat. No. 4,087,485 to Huff discloses a blend comprising about 2-20% by weight ethyelene-propylene copolymer elastomer, 70-90% by weight polypropylene, and about 1-15% by weight LDPE. The elastomer may further include a nonconjugated diene. The blend may be prepared by mixing with conventional equipment at 350.degree.-400.degree. F. for about 4-7 minutes, with conventional agents employed for curing. U.S. Pat. No. 4,088,714 to Huff discloses a blend comprising 40-90 wt.% EPR, EPM, or EPDM copolymer, 14-20 wt.% cross-linkable low density polyethyelene, and less than 50 wt.% isotactic polypropylene. Three radical generating or crosslinking agents such organic peroxides are used to cross-link the elastomer and the cross-linkable low density polyethylene. Triallylcyanurate is employed to enhance the curing and increase resiliency, tensile strength, and impact strength. U.S. Pat. No. 4,221,882 to Huff discloses blends comprising 45-67% polypropylene, 30-45% polyethylene, and 3.5-11% ethylene-propylene copolymer. The polypropylene and ethylene-propylene compolymer are premixed by conventional means and heated to about 204.degree. C. The pre-blend is then pelletized or powdered and mixed with virgin high density polyethylene, and melt-mixed as an extruder let down, normally at about 204.degree. C. The final blend is then employed for molding parts. U.S. Pat. No. 4,251,646 to Smith, Jr. discloses a blend of 60-90% by weight polypropylene, 30-5% by weight thermoplastic crystalline heteroblock propylene-ethylene copolymer, and 30-5% ethylene-propylene copolymer. The blends are processed by conventional techniques at temperatures above 200.degree. C., are readily extrudable and moldable. U.S. Pat. No. 4,375,531 to Ross discloses visbroken polymeric blends comprising a first component selected from a group consisting of block propylene-ethylene copolymers, reactormade intimate mixtures of polypropylene and randomly oriented copolymers of proplyene and ethylene, and blends of propylene and randomly oriented copolymers of propylene and ethylene, and a second component selected from the group consisting of low density polyethylene, ethylene-vinyl acetate copolymer, acrylate-modified polyethylenes, high density polyethylenes, ethylene-propylene rubber (EPR or EPDM), and blends thereof. The method for producing the composition comprises first blending the components, and then visbreaking the resulting blend. The visbreaking may be carried out in the presences of peroxide concentrations of 50-2,000 ppm, and melt temperatures of 350.degree.-550.degree. F., in a single or twin screw extruder. Thermal visbreaking, at temperatures in excess of 550.degree. F. and the absence of free radial initiators and process or heat stabilizer additives, can also be used. "Structure and Properties of Rubber Modified Polypropylene Impact Blends," F. C. Stehling, T. Huff, C. S. Speed, and G. Wissler, Journal of Applied Polymer Science, Vol. 26, pp. 2693-2711 (1981), discloses the dispersion of poly(ethylene-co-propylene) (PEP) rubber and high density polyethylene (HDPE) in polypropylene (PP) blends. Various PP-PEP blends, such as 90-10, 85-15, and 80-20 wt.% ratios, and PP-PEP-HDPE blends including 80-10-10, 85-7.5-7.5, and 90-5-5 wt.% ratios, were studied. In such ratios, PEP was dispersed at a discontinuous phase within a continuous phase of PP in the two component blends. In the three component blends, a discontinuous phase of particles of PEP and HDPE was dispersed within a continuous phase of PP; the particles of the discontinuous phase comprised an interior region of HDPE surrounded by an outer layer of PEP. None of these references discloses or suggests the use of the elastomer compositions disclosed in the COZEWITH et al. patent or applications in such plastic-elastomer blends. SUMMARY OF THE INVENTION It is, therefore, an object of the invention to provide and novel and improved elastomer-plastic blends, utilizing the elastomer compositions disclosed in the COZEWITH et al. patent and applications. According to the invention, an elastomer-plastic composition is provided which comprises: (a) at least one copolymer having at least M.sub.w /M.sub.n less than 2 and a M.sub.z /M.sub.w less than 1.8; and (b) at least one plastic composition. Preferably, the at least one copolymer has M.sub.w /M.sub.n less than 1.4, and M.sub.z /M.sub.w less than 1.3. The at least one copolymer may comprise ethylene and alpha-olefin monomer. Preferably, the alpha-olefin monomer contains 3-18 carbon atoms. Most preferably, it is propylene. Ninety-five (95) wt.% of the copolymer chains of the copolymer may have an ethylene composition that differs from its average weight percent ethylene composition by not more than 15 wt.%, and at least two portions of essentially each copolymer chain of the first copolymer, each portion comprising at least 5 wt.% of the chain, may differ in composition from one another by at least about 5 wt.% ethylene. The copolymer may be an ethylene propylene terpolymer, which may comprise ethylene, propylene, and a non-conjugated diene selected from the group consisting of ethylidene norborene, 1,4-hexadiene, dicyclopentadiene, vinyl norbornene, methylene norbornene, and mixtures thereof. The plastic composition may be a thermoplastic composition, and may further be selected from a group consisting of polypropylenes, polyethylenes, ethylene/vinyl acetate copolymers, polyamides, polyphenyl oxides, polycarbonates ethylene/methyl acrylate copolymers, polymethyl methacrylates, polyvinyl chlorides, acrylonitrile-butadiene-styrenes, polyethyl methacrylates, polystyrenes, polybutylenes, polyesters, acetals, alkyds, polyvinyl acetates, acrylics, and heteroblock propyleneethylene copolymers. Preferably, the thermoplastic composition is polypropylene, or a heteroblock propylene-ethylene copolymer. Where the thermoplastic composition is polypropylene, it preferably comprises approximately 98-50% by weight of the composition of the invention, with the at least one copolymer comprising approximately 2-50% by weight of the composition. Where the thermoplastic composition is the heteroblock copolymer, this copolymer preferably comprises approximately 98-50% by weight of the composition. This heteroblock copolymer preferably comprises approximately 50-98% by weight propylene block and approximately 2-50% by weight post block of ethylene and propylene. This post block preferably comprises 20-78% by weight ethylene. The composition of the invention may include two or more plastics, such as polyethylene and polypropylene. In the composition in the invention, the one or more plastic compositions may take the form of a continuous phase, and the one or more copolymers may take the form of a discontinuous phase dispersed within this continuous phase. In such an embodiment, such continuous phase is preferably polypropylene comprising at least 90 wt.% of the composition, and the discontinuous phase is ethylenepropylene copolymer, ethylene-propylene terpolymer, or a combination thereof, and comprises approximately 10 wt.% or less of the composition. The composition of the invention may further take the form of a continuous phase comprising a first plastic composition, and a discontinuous phase, dispersed within this continuous phase, comprising a second plastic composition and at least one copolymer. In such an embodiment, the first plastic composition is preferably polypropylene, and the second plastic composition is preferably polyethylene; the copolymer is preferably an ethylene-propylene copolymer, an ethylene-propylene terpolymer, or mixtures thereof. Most preferably, the polypropylene comprises at least 85 wt.% of the composition, the polyethylene comprises approximately 5 wt.% or less of the composition, and the indicated copolymer or copolymers comprises approximately 10 wt.% or less of the composition. The at least one copolymer of the composition of the invention may comprise a plurality of copolymer chains, substantially each of which comprises a first segment, being in the form of one contiguous or a plurality of discontinuous segments, comprising a copolymer of ethylene and an alpha-olefin; and a second segment comprising a copolymer of ethylene, an alpha-olefin, and a coupling agent, said second segment constituting less than 50% by weight of said copolymer chain and being in the form of one contiguous segment or a plurality of discontinuous segments. The coupling agent is cross-linkable under conditions which do not cross-link said first segment to any substantial extent. Preferably, this copolymer has at least one of M.sub.w /M.sub.n less than 2 and a M.sub.z /M.sub.w less than 1.8. The indicated alpha-olefin may be propylene. The coupling agent may be a Ziegler copolymerizable diene preferably selected from the group consisting of norbornadiene, vinyl norbornene, and butenyl norbornene. In the alternative, the coupling agent may be a cross-linkable diene preferably selected from the group consisting of ENB, 1,4-hexadiene and dicyclopentadiene. The elastomer of the composition of the invention may comprise at least one nodular ethylene-alpha-olefin copolymer product of copolymer chains comprising a nodule region of substantial cross-linking of copolymer chains second segments, with substantially uncrossed-linked copolymer chain first segments extending therefrom. Preferably, the chain first segments of the nodular copolymer are in the form of one contiguous segment or a plurality of discontinuous segments, and comprise a copolymer chain of ethylene and an alpha-olefin, while the chain second segments comprise a copolymer of ethylene, alpha-olefin, and a coupling agent. Most preferably, these second segments constitute less than 50% by weight of each copolymer chain formed by the first and second segments, and are in the form of one contiguous segment or a plurality of discontinuous segments. In this embodiment, the coupling agent may be a Ziegler copolymerizable diene, preferably selected from the group consisting of norbornadiene, vinyl norbornene, and butenyl norbornene. Alternatively, the coupling agent may be a cross-linkable diene, preferably selected from a group consisting of ENB, 1,4-hexadiene, and dicyclopentadiene. The elastomer of the composition of the invention may comprise a copolymer of ethylene and at least one other alpha-olefin monomer, which copolymer is a superposition of two or more copolymers modes each having a MWD characterized by at least one of M.sub.w /M.sub.n less than 2 and a M.sub.z /M.sub.w less than 1.8. Preferably, the at least one other alpha-olefin monomer contains 3-18 carbon atoms. This copolymer may consist essentially ethylene, propylene, and straight chain acyclic diene selected from the group consisting of 1,4-hexadiene and 1,6-octadiene. Alternatively, this copolymer may consist essentially of ethylene, propylene, and 5-ethylidene-2-norbornene. The composition of the invention may comprise: (a) an ethylene-alpha olefin copolymer; (b) one or more plastic compositions; and (c) at least one copolymer, in an amount equal to approximately 80 wt.% or less of the composition, comprising a plurality of Ziegler-Natta catalyzed polymer chains, substantially each of said chains being end capped with at least one functional group-containing unit which is otherwise essentially absent from said copolymer chains, said functional group being incorporated in a polymer selected from the group consisting of: ##STR1## the monomers thereof, and the mixtures thereof; wherein R.sub.1 through R.sub.4 are hydrocarbons with 1-30 carbon atoms selected from the group consisting of saturated or unsaturated, branched or unbranched, aliphatic, aromatic, cyclic, or polycyclic hydrocarbons, wherein R.sub.5 is the same as R.sub.4 but may additionally be hydrogen; and wherein x=1-10,000. In the alternative the at least one copolymer present in an amount equal to 80 wt.% or less of the composition may comprise a plurality of copolymer chains, substantially each of said chains being a Ziegler-natta catalyzed polymer chain end capped with at least one functional group-containing unit which is otherwise essentially absent from said polymer chain. The indicated functional group may be selected from the group consisting --CO.sub.2 H, --OH, --SH, --X, --C--C--benzene, --C--C--(pyridine), --SO.sub.2 H, SO.sub.3 H, and mixtures thereof, wherein X is a halide selected from the group consisting of fluorine, chlorine, bromine, and iodine. Alternatively this functional group may be selected from the group consisting of isocyanates, urethanes, nitriles, aromatic ethers and aromatic carbonates. The indicated functional group containing unit may be selected from the group of polymers consisting of copolymers of ethylene and vinyl acetate; ethylene and acrylic acid esters; vinyl acetate and fumaric acid esters; styrene and maleic acid esters; olefins and maleic acid esters; homopolyacrylates; and epoxidized natural rubber. The composition of the invention may further comprise: (a) at least one copolymer which comprises a plurality of copolymer chains, substantially each comprising: I. a first segment, being in the form of one contiguous segment or a plurality of discontinuous segments, comprising a copolymer of ethylene and an alpha-olefin; and II. a second segment comprising a copolymer of ethylene, an alpha-olefin, and at least one halogen-containing monomer selected from the group consisting of: A. an olefinic chlorosilane of the formula SiRR.sub.x 'Cl.sub.3-X wherein: i) x is in the range 0-2; ii) R is a Ziegler copolymerizable olefin; and iii) R' is a hydrocarbon with 1-30 carbon atoms selected from the group consisting of saturated or unsaturated as well as branched or unbranched aliphatic, aromatic, cyclic, and polycyclic hydrocarbons; B. an olefinic hydrocarbon halide of the formula RR'X wherein: i) R is a Ziegler copolymerizable olefin; and ii) R' is a hydrocarbon with 1-30 carbon atoms selected from the group consisting of saturated or unsaturated as well as branched or unbranched aliphatic, aromatic, cyclic, and polycyclic hydrocarbons; and iii) X is a halogen; said second segment constituting less than 50 percent by weight of said copolymer chain, said second segment being in the form of one contiguous segment or a plurality of discontinuous segments; said at least one halogen-containing monomer being cross-linkable under conditions which do not cross-link said first segment to any substantial extent; and (b) at least one plastic composition. Alternatively, the elastomer of the composition of the invention may comprise: (a) at least one copolymer consisting essentially of a plurality of copolymer chains having at least one of M.sub.w /M.sub.n less than 2 and M.sub.z /M.sub.w less than 1.8, said copolymer comprising ethylene, an alpha-olefin, and at least one halogen-containing monomer selected from the group consisting of: I. an olefinic chlorosilane of the formula: SiRR.sub.x 'Cl.sub.3-x wherein; i) x is in the range of 0-2; ii) R is a Ziegler copolymerizable olefin; and iii) R' is a hydrocarbon with 1-30 carbon atoms selected from the group consisting of saturated or unsaturated as well as branched or unbranched aliphatic, aromatic, cyclic, and polycyclic hydrocarbon; and II. an olefinic hydrocarbon halide of the formula: RR'X wherein: i) R is a Ziegler copolymerizable diene; and ii) R' is a hydrocarbon with 1-30 -carbon atoms selected from the group consisting of saturated or unsaturated as well as branched or unbranched aliphatic, aromatic, cyclic, and polycyclic hydrocarbons; and iii) X is a halogen. This copolymer may further comprise a non-conjugated diene selected from the group consisting of 5-ethylidene-2-norbornene, 1,4-hexadiene, dicylopentadiene, and mixtures thereof. Further, in the alternative, the elastomer of the invention may comprise at least one nodular copolymer product of copolymer chains comprising: A. a nodule region of substantial cross-linking of copolymer chain second segments substantially cross-linked by at least one cross-linking agent, substantially each of said second segments comprising a copolymer of ethylene, an alpha-olefin, and at least one halogen-containing monomer selected from the group consisting of: (a) an olefinic chlorosilane of the formula SiRR.sub.x 'Cl.sub.3-x wherein: i) x is in the range 0-2; ii) R is a Ziegler copolymerizable olefin; and iii) R' is a hydrocarbon with 1-30 carbon atoms selected from the group consisting of saturated or unsaturated as well as branched or unbranched aliphatic, aromatic, cyclic, and polycyclic hydrocarbons; and (b) an olefinic hydrocarbon halide of the formula RR'X wherein: i) R is a Ziegler copolymerizable olefin; ii) R' is a hydrocarbon with 1-30 carbon atoms selected from the group consisting of saturated or unsaturated as well as branched or unbranched aliphatic, aromatic, cyclic, and polycyclic hydrocarbons; iii) X is a halogen; and B. substantially uncross-linked copolymer chain first segments extending therefrom, substantially each of said first segments comprising a copolymer of ethylene and an alpha-olefin; said halogen-containing monomer being cross-linkable under conditions which do not cross-link said first segments to any substantial extent. Where the indicated halogen-containing monomer is an olefinic chlorosilane, it may be selected from the group consisting of vinyl dimethylchlorosilane, vinyl ethyl dichlorosilane, 1-hexenyl-6-dimethylchlorosilane, 1-hexenyl-6-trichlorosilane, 1-octenyl-8-trichlorosilane, phenyl allyldichlorosilane, 5-trichlorosilyl-2-norbornene, and 5-methyldichlorosilyl-2-norbornene. Where the indicated halogen-containing monomer is an olefinic hydrocarbon halide, it may be selected from the group consisting of 5-chloromethyl-2-norbornene and 2-parachloromethylphenyl-5-norbornene. These copolymers may be linked to the plastic through the indicated halogen-containing monomer. Where the halogen-containing monomer is an olefinic chlorosilane, such a link will form where the plastic composition is a polycarbonate, a polyamide, a polyester, a polyphenylene oxide, or an acetal. Where the halogen-containing monomer is an olefinic hydrocarbon halide, the link will form where the plastic composition is a polyamide. The composition of the invention may also be subjected to curing. The invention is also directed to the process for preparing the previously indicated compositions. In one embodiment of the process, where the elastomer comprises a copolymer having at least one of M.sub.w /M.sub.n less than 2 and M.sub.z /M.sub.w less than 1.8, this elastomer is formed from a reaction mixture comprised of catalyst, ethylene, and at least one other alpha-olefin monomer, comprising conducting the polymerization of said at least one copolymer: (a) in at least one mix-free reactor; (b) with essentially one active catalyst species; (c) using at least one reaction mixture which is essentially transfer-agent free; (d) in such a manner and under conditions sufficient to initiate propagation of essentially all of said copolymer chains simultaneously, wherein chains of said at least one copolymer are dispersed within the reaction mixture. This resulting elastomer is then blended with one or more plastics to form the composition of the invention. In preparing the composition of the invention wherein the elastomer comprises a polymodal MWD copolymer, this copolymer may be prepared by varying the previously indicated reaction process by any one of several ways. In one of these variations, reaction mixture is withdrawn from the reactor at at least two predetermined times after initiation of the polymerization and the copolymer withdrawn at each of said times is blended to form the polymodal MWD copolymer. Another variation employs at least two catalyst, each of which initiates the growth of polymer chains that obtain a different average molecular weight than that initiated by the other catalyst. In a third alternative, at least two different mix-free reactors are employed to form the different modes which are then blended to produce the polymodal MWD copolymer. In a fourth embodiment, the polymodal MWD copolymer is produced by adding a catalyst reactivator to the reaction mixture after polymerization has progressed for a finite period of time. A fifth embodiment employs a catalyst system which generates multiple active catalyst species, each initiating the growth of polymer chains that obtain a different average molecular weight than those produced by other catalyst species. To prepare a composition of the invention wherein the elastomer is a nodular compolymer, the previously indicated reaction process is varied by permitting the polymerization to continue to at least 50% completion, at which point a coupling agent is introduced into the reaction mixture. The reaction is thereafter permitted to continue, thereby incorporating the coupling agent into the polymer so as to form a nodular copolymer wherein the polymer chains are linked to the coupling agent. The product which results is blended with one or more plastics to produce the composition of the invention. To prepare an elastomer for the composition of the blend comprising ethylene, one or more alpha-olefin monomers, and at least one halogen containing monomer selected from the group consisting of (a) olefinic chlorosilane of the formula SiRR.sub.x 'Cl.sub.3-x wherein; i) x is in the range 0-2; ii) R is a Ziegler compolymerizable olefin; and iii) R' is a hydrocarbon with 1-30 carbon atoms selected from the group consisting of saturated or unsaturated as well as branched or unbranched aliphatic aromatic cyclic, and polycyclic hydrocarbons; and (b) olefinic hydrocarbon halide of the formula RR'X wherein; i) R is a Ziegler copolymerizable olefin; and ii) R' is a hydrocarbon with 1-30 carbon atoms selected from the group consisting of saturated or unsaturated as well as branched or unbranched aliphatic, aromatic, cyclic, and polycyclic hydrocarbons; and iii) X is a halogen; wherein ethylene, one or more alpha-olefin monomers, and at least one of the previously indicated halogen-containing monomers are introduced into the previously described reaction process. The resulting copolymer is blended with one or more plastic compositions to produce the composition of the present invention. A narrow-broad ethylene alpha-olefin copolymer, i.e., an ethylene alpha-olefin copolymer composition comprising: (i) a first copolymer having at least one of M.sub.w /M.sub.n less than 2 and M.sub.z /M.sub.w less than 1.8; and (ii) a second copolymer having both M.sub.w /M.sub.n greater than or equal to 2 and M.sub.z /M.sub.w greater than or equal to 1.8; may be prepared for incorporation into the composition of the invention by forming the first polymer by the previously described process, reacting a second reaction mixture to produce the second copolymer, and then blending the first and second copolymers to form the elastomer for use with the composition of the invention. Subsequently, this elastomer is blended with one or more plastic compositions to form the composition of the invention. Any of these indicated processes may further be subjected to a curing step for curing the composition. The blends of the invention can have utility in high impact applications. They can be employed in films, laminates, fabric coatings, tapes, and molded and extruded products, including sheet extrusion products. The preferred elastomers for use in the blends of the invention are the single mode narrow MWD EPM and EPDM copolymers. The preferred plastic compositions are polypropylene, polyethylene, particularly high density polyethylene, polystyrene, ethylene/vinyl acetate copolymer, ethylene/methyl methacrylate copolymer, and heteroblock propylene-ethylene copolymers. The use of polypropylene and polyethylene together is also preferred. Where the plastic composition of the invention is polypropylene, the blends preferably comprise approximately 2-50 weight percent elastomer and approximately 98-50 weight percent polypropylene. Blends employing heteroblock propylene-ethylene copolymer preferably comprise approximately 2-50 weight percent of elastomer and approximately 98-50 weight percent of the heteroblock copolymer. The heteroblock copolymer preferably comprises approximately 50-98 weight percent, more preferably approximately 60-95 weight percent, of a polypropylene block, and preferably approximately 2-50 weight percent, more preferably approximately 5-40 weight percent of a post block of ethylene and propylene. The post block preferably comprises approximately 20-75 weight percent, more preferably 25-50 weight percent ethylene. |
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