MXPA99007007A - Heteromorphic polymer compositions - Google Patents

Abstract

The subject invention pertains to heteromorphic polymer compositions characterized as comprising:(a) a homogeneous linear or substantially linear ethylene/&agr;-olefin interpolymer backbone;and (b) a branch appending from the backbone, which branch comprises an ethylene homopolymer or ethylene/&agr;-olefin interpolymer having a density which is at least 0.004 g/cm3 greater than that of the backbone. At least one of the backbone polymer or the branch polymer may be optionally functionalized to promote adhesion to polar surfaces. The heteromorphic polymer compositions of the invention exhibit enhanced upper service temperature. Also disclosed is a process for preparing the heteromorphic polymer compositions of the invention.

Description

HETEROMORPHIC POLY ERIC COMPOSITIONS The present invention relates to heteromorphic olefin polymers. In particular, the present invention relates to olefin polymers comprising a homogeneously branched or substantially linear linear ethylene / α-olefin interpolymer backbone, and a higher density ethylene homopolymer or long chain ethylene interpolymer / α-olefin leaving the central structure of the interpolymer. The homogeneous ethylene / α-olefin interpolymers are characterized by narrow molecular weight distributions and narrow short-chain branching distributions. In addition, homogeneous ethylene interpolymers containing long chain branches, known as "substantially linear" ethylene polymer, are described and claimed in U.S. Patent Number 5,272,236 and in U.S. Patent Number 5,278,272. The absence of low molecular weight waxy components, and the ability to evenly distribute the comonomer has allowed the production of high quality elastomers, such as ethylene / propylene, ethylene / butene and ethylene / octene elastomers, etc. However, since the homogeneously linear and substantially linear ethylene polymers lack the characteristic highly linear fraction of the heterogeneously branched polyethylene (and thus of the high crystalline melt peak), homogeneously linear and substantially linear ethylene polymers tend to have a resistance to higher bad temperature, especially when the polymer density is less than 0.920 grams / cm3, than the heterogeneously branched polymers of the same density. For example, homogenously linear and substantially linear elastomers may lose their strength at 60 ° C or less. This has been attributed to the fact that these low density polymers have a molecular structure that is characterized by the presence of marginal micelles, and typically lacks higher melting sheet structures. Although the differential is less pronounced, even homogeneously linear and substantially linear ethylene polymers of higher density having lamellar structures generally melt at lower temperatures than their heterogeneously branched counterparts. Regardless of the polymerization catalyst, the polyethylenes face a practical use limitation above their crystalline melting point, which does not exceed about 140 ° C. Through the mixing of high degrees of crystallinity of the polyethylene with low crystallinity elastomeric grades, it is possible to raise the temperature of the use of the elastomeric grades. However, further improvements in resistance to high temperatures are desired. However, in addition, speaking in general terms, as the amount of fraction of greater density increases, the resistance increases at high temperature, while the modulus increases (and thus, the elastomeric properties, in the case of mixtures with ethylene polymers homogeneously linear or substantially linear having a density less than 0.900 grams / cm3, decreases undesirably). In the case of mixtures with homogeneously linear and substantially linear ethylene polymers having a density greater than 0.900 grams / cm3, as the amount of the higher density fraction increases, resistance to high temperatures increases, while undesirably tear resistance and the impact resistance decrease. U.S. Patent No. 5,530,072 discloses polymers that exhibit long chain branching formed by self-insertion of a linear polyethylene using a free radical initiator. Although this self-insertion serves to increase the molecular weight of polyethylene to improve melt strength, it does not affect the crystallinity of polyethylene, and does not affect the high temperature resistance of polyethylene. U.S. Patent No. 5,346,963 discloses insert-modified substantially linear ethylene polymers, which are optionally blended with thermoplastic polymers, such as high density polyethylene, linear low density polyethylene, and low density polyethylene. The industry would find advantage in an elastomer that had improved performance at high temperatures without sacrificing modulus and / or scrap resistance and impact resistance.

This improved performance at high temperature can show an advantage, such as the sole of the shoes that better withstand the heat of the clothes dryer. In another embodiment, this improved performance at high temperature may show advantages, for example, in pressure sensitive adhesives exhibiting drag resistance. As used herein, the term "polymer" means a compound prepared by polymerization monomers, either of the same or different type. The term generic polymer thus encompasses the term "homopolymer", usually used to refer to polymers prepared from only one type of monomer, and the term "interpolymer", as defined hereinafter. The term "interpolymer" means polymers prepared by the polymerization of at least two different types of monomers. The generic term "interpolymer" thus includes the term "copolymers", which is usually used to refer to polymers prepared from two different monomers, as well as to polymers prepared from more than two different types of monomers. The present invention is in a single polymer composition comprising: (A) a linear structure of linear or substantially linear homogeneous ethylene / α-olefin interpolymer; and (B) an ethylene homopolymer or an ethylene / α-olefin interpolymer that connects the central structure of the interpolymer and which has a density of at least 0.004 grams / cm 3 greater than that of the first interpolymer core structure. These polymer compositions will resist deformation under high temperatures better than a comparative physical mixture or a reactor mixture of the first and second interpolymers. This improved performance at high temperatures is reflected in higher load service temperature (ULST) values, that is, the tendency of heteromorphic polymer compositions to fail due to softening / melting, as measured using a Reheometrics Solids Analyzer. using the procedure presented later. Although one does not wish to be limited by theory, it is believed that the scientific material principle used to improve the high temperature performance of homogeneous linear or substantially linear elastomers is illustrated in Figure 1. As shown in Figure 1, the elastomer it acts as a soft segment to provide flexibility at the ambient temperature of the heteromorphic polymer composition. The insert of a hard segment, such as a high density polyethylene, having a higher crystalline melting point, improves the value of the service temperature under load, since the hard segments co-crystallize in their own intermixed domains and serve to tie the elastomer chains in a three dimensional network. Depending on the composition of the branched polymer and the method of incorporating the branching, the branching can take many forms, some of which are shown in Figure 2. Figure 2-1 shows a substantially linear copolymer core structure with three different ways of connecting the polymer branch. Figure 2-1 (a) illustrates the branching resulting from a "H link" with the core structure polymer. This could, for example, be introduced by the random cross-linking of the core structure polymer of the precursor polymer with the heteromorphic long chain branch. Figure 2-1 (b) illustrates a long chain branching that binds to the core polymer in two (or more) positions. Provided the long chain branching can still be co-crystallized or forms a "hard" phase, so that the polymer's temperature and / or physical resistance properties are improved, this method of incorporating long chain branching is acceptable and it is within the scope of our definition of long chain branching. Figure 2-1 (c) illustrates the formation of a "T" with the central structure polymer. This could, for example, being the result of the insertion of a reactive end group of a heteromorphic long chain branching precursor polymer with the core structure polymer, or it could result from the copolymerization of the reactive end group, such as vinyl with monomers during the polymerization of the central structure polymer (in this case, of course, the "core structure polymer" is only a concept and is not substantially present in pure form). Figures 2-2 illustrate an example of variation where a linear copolymer of the core structure (2-2) has heteromorphic long chain branches of the "T" type, such as that resulting from copolymerization or inserted end groups. The ethylene / α-olefin interpolymer (A) which constitutes the core structure of the heteromorphic olefin polymer of the invention will be either a homogeneous linear or substantially linear interpolymer of ethylene / α-olefin, of which both are described with more detail later. The density of the central structure polymer depends on the type and amount of comonomer used. The density can be controlled according to methods known to those skilled in the art, in order to control the softness of the polymer over the range from highly amorphous elastomeric grades to highly crystalline non-elastomeric grades. The choice of the density of the core structure polymer will depend on the requirements of each application in accordance with the performance requirements known to those skilled in the art. Typically, however, the density of the core structure polymer will be less than 0.920 grams / cm3, preferably less than 0.900 grams / cm3, preferably less than 0.880 grams / cm3. In applications where the best elastomeric properties are required, the density of the core structure polymer will be less than 0.870 grams / cm3, preferably less than 0.865 grams / cm3, with densities as low as 0.850 grams / cm3. The molecular weight of the polymer of the central structure can also vary according to each system. When the branched polymer is bound to the central structure polymer by crosslinking or insertion, it may be preferred to reduce the molecular weight of the interpolymer of core structure to reduce gel formation, particularly if the branched polymer has high molecular weight or is multifunctional in reactive sites . It is an aspect of this invention that excellent physical properties can be obtained even with relatively low molecular weight central structure polymers, as measured by the optimized connectivity faced by the heteromorphic character of the compositions of the invention. Thus, it is possible to obtain good physical properties and good processability simultaneously. However, typically, the core structure polymer will have a melting point (12) of from 0.01 to 10,000 grams / 10 minutes, and preferably from 0.01 to 1,000 grams / 10 minutes. Especially the preferred melt indexes are greater than 10 grams / 10 minutes, more preferably greater than 20 grams / 10 minutes. Note that for low molecular weight polymers, ie, polymers having a melt index greater than 1,000 grams / 10 minutes, the molecular weight can be indicated by measuring the melt viscosity of the polymer at 177 ° C. Melt viscosities at 177 ° C of polymers having melt indices of 1,000 grams / 10 minutes, and 10,000 grams / 10 minutes, as measured by the technique set forth in the section below on Test Procedures, are approximately 8,200 and 600 centipoises, respectively.

The branched polymer (B) which is attached to the central structure of the polymer (A) can be any polymer that can be copolymerized with the monomers during the production of the polymer of central structure, or that can be inserted or cross-linked with the polymer of structure central, and having a density that is at least 0.004 grams / cm3, preferably at least 0.006 grams / cm3, more preferably at least 0.01 grams / cm3 higher than the central structure polymer. Preferably, the branched polymer (B), in its pure state, will have a glass transition temperature (Tg) or crystalline melting point (Tm), which is at least 10 ° C, preferably 20 ° C, and more preferably at least 50 ° C higher than the glass transition temperature or the crystalline melting point temperature (whichever is higher) of the central structure polymer in its pure state. Note that for the purpose of this invention, the term "insert" means linking a final group of the branched polymer with the central structure polymer, while the term "crosslinking" means, in a limited manner, connecting via one or more links anywhere along the long chain branching precursor (that is, not a final group) to form the heteromorphic long chain branched composition instead of a crosslinked network. Non-limiting examples of heteromorphic long-chain branched materials include ethylene / α-olefin interpolymers and heterogeneously and homogeneously branched linear homopolymers, as well as ethylene / α-olefin interpolymers and substantially linear ethylene homopolymers, each of which is described in more detail later. These branched polymers can optionally be functionalized. A suitable branching polymer for a core structure polymer may not be suitable for another core structure polymer. For example, a suitable branched polymer for a substantially linear or homogeneously linear ethylene / octene interpolymer having a density of 0.865 grams / cm 3 would be an ethylene / octene polymer having a density of 0.900 grams / cm 3. However, the same branched polymer would not be suitable for use in conjunction with a polymer backbone which is a homogeneously linear or substantially linear interpolymer of ethylene / octene having a density of 0.920 grams / cm 3, since the crystalline melting point of the previous one is not at least 10 ° C higher than the crystalline melting point of the last one (and in fact, it is significantly lower). The heteromorphic long chain branching will also be of sufficient molecular weight to be able to co-crystallize or form a phase with other branched polymer molecules or with additionally added polymer. Preferably, the heteromorphic long chain branch will have a weight average molecular weight (Mw) of at least 1,000, preferably at least 3,000, as measured according to the method set forth in the Test Methods section below.

The amount of polymer of central structure should be sufficient to make the continuous or co-continuous phase in the mixture of central structure polymer and heteromorphic long-chain branched polymer. In particular, the weight ratio of the polymer of central structure against the branched polymer will generally be greater than 1: 3, preferably at least 1: 2, and more preferably greater than 1: 1. Those skilled in the art will recognize that the optimum ratio will vary with respect to the application and the resulting changes in preferences for elastomer properties, high temperature properties, modulus / stiffness, etc. The average number of heteromorphic long chain branches per molecule of polymer backbone will be sufficient to provide the final polymer composition with an improvement in temperature resistance as measured by RSA (Rheometric solid analyzer) and / or an improvement in tensile strength that is greater than that provided by a simple physical mixture of affordable polymers without copolymerization, insertion and crosslinking. Preferably, the compositions of the invention will exhibit a resistance to temperature measured by Rheometric solids analyzer of at least 10 ° C, preferably at least 15 ° C more than that of the physical mixture of comparable polymers. Preferably, the compositions of the invention will exhibit a tensile strength that is at least 70 percent that of the physical mixture of the buyable polymers, more preferably at least 85 percent, more preferably equal to or greater than that of the physical mixture of affordable polymers, with tensile strengths that are finally 120 percent of the physical mixture of affordable polymers, easily reaching. The average number of heteromorphic long chain branches per molecule of polymer core structure, however, will not be so great as to reduce the elastomeric properties of the polymer core structure to an unacceptable level. For example, when the core polymer has a density of less than 0.900 grams / cm 3, the composition of the invention will preferably have a percentage elongation that is at least 40 percent, more preferably at least 50 percent, yet more preferably, it is at least 60 percent of that of the mixture of buyable polymers, with compositions exhibiting percentage elongations that equal or exceed that of the affordable mixture being easily reached. The ethylene polymers useful as the polymer backbone (A) and the heteromorphic long chain branch (B) can independently be interpolymers of ethylene and at least one α-olefin. Suitable α-olefins are represented by the following formula: CH 2 = CHR wherein R is a hydrocarbyl radical. The comonomers forming a part of the central structure polymer (A) can be the same as or different from the comonomers forming the heteromorphic long chain branch (B). R generally has from one to twenty carbon atoms. Suitable α-olefins for use as comonomers in a solution, gaseous phase or mud polymerization process or combinations thereof include α-olefins of 3 to 20 carbon atoms, styrene, tetrafluoroethylene, vinylbenzocyclobutane, 1,4-hexadiene , 1,7-octadiene and cycloalkenes, for example, cyclopentene, cyclohexene, cyclooctene, norbornene (NB), and norbornene-ethylidene (ENB). Preferred a-olefins of 3 to 20 carbon atoms include 1-propylene, 1-butene, 1-isobutylene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene and 1-octene, as well like other types of monomers). Preferably, the α-olefin will be 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, norbornene or norbornene-ethylidene, or mixtures thereof. More preferably, the α-olefin will be 1-hexene, 1-heptene, 1-octene, or mixtures thereof. More preferably, the α-olefin will be 1-octene. Ethylene / α-olefin / diene terpolymers can also be used as the elastomeric polymers of this invention. Suitable α-olefins include the a-olefins described above as convenient for making ethylene α-olefin copolymers. Convenient dienes as monomers for the preparation of these terpolymers are typically non-conjugated dienes having from 6 to 15 carbon atoms. Representative examples of suitable non-conjugated dienes that can be used to prepare the terpolymer include: a) Acyclic straight chain dienes such as 1,4-hexadiene, 1,5-heptadiene and 1,6-octadiene; b) Branched chain acyclic dienes such as 5-methyl-1,4-hexadiene, 3,7-dimethyl-1 -6-octadiene, and 3,7-dimethyl-1,7-octadiene, and 1, 9-decadiene; c) single ring alicyclic dienes such as 4-vinylcyclohexene, 1-allyl-4-isopropyldenecyclohexane, 3-allylcyclopentene,4-allylcyclohexene and 1-isopropenyl-4-butenylcyclohexane; d) ring-bridged and multi-ring alicyclic dienes such as dicyclopentadiene; alkenyl, alkylidene, cycloalkenyl and norbornenes-cycloalkylidenes, such as 5-methylene-2-norbornene, 5-methylene-6-methyl-2-norbornene, 5-methylene-6,6-dimethyl-2-norbornene, 5-propenyl- 2-nobornene, 5- (3-cyclopentenyl) -2-norbornene, 5-ethylidene-2-norbornene, 5-cyclohexylidene-2-norbornene, etc. The preferred dienes are selected from the group consisting of 1,4-hexadiene, dicyclopentadiene, 5-ethylidene-2-norbornene, 5-methylene-2-norbornene, 7-methyl-1,6-octadiene, 4-vinylcyclohexene, etc. A suitable conjugated diene is piperylene. Preferred terpolymers for the practice of the invention are terpolymers of ethylene, propylene and non-conjugated diene (EPDM). These terpolymers are commercially available. The homogeneous polyethylenes that can be used as components (A) and (B) of this invention fall into two broad categories, homogeneous linear polyethylenes and homogeneous substantially linear polyethylene. Both are known. "Homogeneous" polymers are ethylene interpolymers, in which any comonomer is randomly distributed within a given interpolymer molecule and substantially all interpolymer molecules have the same ethylene / comonomer ratio within that interpolymer. Homogeneous polymers are generally characterized by having a single melting peak at -30 ° C and 150 ° C, as determined by differential scanning calorimetry (DSC). The unique melting peak is determined using a differential scanning calorimeter standardized with indium and with deionized water. The method involves sample sizes of 3 to 7 milligrams, a "first heat" of approximately 180 ° C which is maintained for 4 minutes, a cooling at 10 ° C / minute at -30 ° C which is maintained for 3 minutes, and a temperature rise at 10 ° C / minute to 140 ° C for the "second heat". The only melting peak is taken from the heat flow of the "second heat" against the temperature curve. The total heat of fusion of the polymer is calculated from the area under the curve. For polymers having a density of 0.875 grams / cm3 up to 0.910 grams / cm3, the only melting peak can be displayed, depending on the sensitivity of the equipment, a "shoulder" or a "hump" on the low melting side it constitutes less than 1 percent, typically, less than 9 percent, and more typically less than 6 percent of the total heat of fusion of the polymer. This artifact is also observable from homogeneous linear polymers such as Exact ™ resins (available from Exxon Chemical Company), and is discerned based on the slope of the unique melting type that varies monotonously across the melting region of the artifact. This artifact occurs within 34 ° C, typically at 27 ° C, and more typically at 20 ° C from the melting point of the single melting point. The heat of the fusion attributable to an artifact can be determined separately by the specific integration of its associated area under the heat flux against the temperature curve. In addition, or in the alternative, the homogeneity of the polymers is typically described by the Composition Distribution Ramification Index (CDBI), and is defined as the weight percentage of the polymer molecules having a comonomer content within 50 percent of the total medium molar comonomer content. The Branching Index of the Composition of a polymer is easily calculated from data obtained from techniques known in the art, such as, for example, elution fractionation of temperature rise (abbreviated herein as "TREF") as described, for example, in Wild et al., Journal of Polymer Science, Poly, Phys. Ed., Volume 20, page 441 (1982), in the United States Patent Number 4., 798.081 (Hazlitt et al.), Or in U.S. Patent No. 5,089,321 (Chum et al.). The Composition Distribution Branch Index for the homogeneous linear and for the substantially linear ethylene / α-olefin polymers used in the present invention is preferably greater than 50 percent, more preferably greater than 70 percent. The homogeneous polymers will typically have a molecular weight distribution, Mw / Mn, less than, or equal to 3 (when the interpolymer density is less than about 0.960 grams / cm 3), preferably less than, or equal to 2.5. The molecular weight determination is deduced using polyethylene standards in their narrow molecular weight distribution (from Polymer Laboratories) together with the elution volumes. The SLEPs are analyzed by gel permeation chromatography (GPC) on a Waters 150 C high temperature chromatographic unit equipped with a differential refractometer and three columns of mixed porosity. The columns are supplied by Polyer Laboratories and are commonly packaged with pore sizes of 103, 104, 105 and 106. The solvent is 1, 2,4-trichlorobenzene, of which 0.3 percent by weight of sample solutions are prepared for injection. The flow rate is 1.0 milliliters / minute, the operating temperature of the unit is 140 C, and the injection size is 100 microliters. The equivalent polyethylene molecular weights are determined using appropriate Mark-Houwink coefficients for polyethylene and polystyrene (as described by Williams and Ward in Journal of Polymer Science, Polymer Letters, Volume 6, page 621, 1968) to derive the Mp equation ? | ietl? eno = a • (MPoi? est? reno) - In this equation, a = a 0.4316 and b = 1.0. The average molecular weight, Mw, is calculated in the usual manner according to the formula: Mw =? (W, x M,) wherein w, and M, are the weight and molecular weight fractions, respectively, of the fraction ia that is eluted from the column of gel permeation chromatography. Linear homogeneous ethylene polymers have been commercially available for a long time. As exemplified in U.S. Patent No. 3,645,992 to Elston, linear homogeneous ethylene polymers can be prepared in conventional polymerization processes using Ziegler type catalysts such as, for example, zirconium and vanadium catalyst systems. U.S. Patent No. 4,937,299 to Ewen et al., And U.S. Patent No. 5,218,071 to Tsutsui et al., Describe the use of metallocene catalysts, such as zirconium and hafnium-based catalyst systems, for the preparation of linear homogeneous ethylene polymers. Linear homogeneous ethylene polymers are typically characterized as having a molecular weight distribution, Mw / Mn, of about 2. Commercially available examples of linear homogeneous ethylene polymers include those sold by Mitsui Petrochemical Industries, as Tafmer ™ resins and by Exxon Chemical Company, ExactMR resins. Substantially linear ethylene polymers (SLEPs) are homogeneous polymers having long chain branching. Patents 5,272,236 and 5,278,272 are described in U.S. Patents. The substantially linear ethylene polymers are made by the lnsitew'R Process and the Catalyst Technology, and are available from The Dow Chemical Company as Aff inity ™ polyolefin elastomers (POP) and from DuPont Dow Elastomers, LLC as the elastomers of Polyolefin Engage R (POE). Substantially linear ethylene polymers can be prepared via the solution, the slurry or the gas phase, preferably the solution phase, the polymerization of ethylene and one or more optional comonomers of α-olefin in the presence of catalysts of restricted geometry, such as is described in European Patent Application 416,815-A. The term "substantially linear" means that, in addition to the short chain branches attributable to the incorporation of homogeneous comonomer, the ethylene polymer is further characterized by having long chain branches, such that the central structure of the polymer is replaced with an average of 0.01 to 3 long chain branches / 1,000 carbon atoms. Preferred substantially linear polymers for use in the invention are substituted with 0.01 long chain branches / 1,000 carbon atoms up to 1 long chain branch / 1,000 carbon atoms, and more preferably from 0.05 long chain branches / 1,000 carbon atoms carbon up to 1 long chain branch / 1,000 carbon atoms. "Long chain branching" (LCB) means a chain length of at least 6 carbon atoms, above which the length can not be distinguished using 13C nuclear magnetic resonance spectroscopy. Each long chain branch has the same comonomer distribution as the core structure of the polymer and can be as long as the central structure of the polymer to which it is attached. The presence of the long chain branching in the ethylene polymers can be determined using 13 C nuclear magnetic resonance spectroscopy and quantified using the method described by Randall (Rev. Macromol. Chem. Phys., C.29, V. 2 and 3, pages 285-297). As a practical matter, 13C nuclear magnetic resonance spectroscopy can not determine the length of the long chain branch beyond 6 carbon atoms. However, there are other known techniques useful for determining the presence of long chain branches in ethylene polymers, which include ethylene / 1-ketene interpolymers. Two of these methods are gel permeation chromatography coupled with the low-angle laser light scattering detector (GPC-LALLS) and gel permeation chromatography coupled with a differential viscometer detector (GPC-DV). The use of these techniques for the detection of long chain branching and the underlying theories have been well documented in the literature. See, for example, Zimm, G.H. and Stockmayer, W.H., J. Chem. Phys., 17, 1301 (1949) and Rudin A., Modern Methods of Polvmer Characterization, John Wiley & amp;; Sons, New York (1991), pages 103-112, both of which are incorporated by reference. A. Willem deGroot and P. Steve Chum, both of The Dow Chemical Company, as of October 4, 1994 Conference of the Federation of Analytical Chemistry and Spectroscopy Society (FACSS) in St. Louis, Missouri, presented data demonstrating that gel permeation chromatography coupled with a differential viscosimeter detector is a technique useful for quantifying the presence of substantially linear ethylene polymers. In particular, deGroot and Chum found that the level of long-chain branches in substantially linear polyethylene samples measured using the Zimm-Stockmayer equation correlated well with the level of long-chain branches measured using nuclear magnetic resonance spectroscopy with 13C. In addition, deGroot and Chum found that the presence of octene does not change the hydrodynamic volume of the polyethylene samples in solution and, as such, one can count the molecular weight increase attributable to the short chain branches of octene knowing the mole percent of the octene in the sample. By deconvoluining the contribution to the molecular weight increase attributable to the short chain branches of 1-octene, deGroot and Chum showed that gel permeation chromatography coupled with the differential viscometer detector can be used to quantify the level of long chain branches. in substantially linear ethylene / octene copolymers. deGroot and Chum also showed that a graph of Log (l2, Fusion index) as a function of Log (GPC Molecular Weight Average Weight) determined by gel permeation chromatography coupled with a differential viscometer detector illustrates that aspects of long chain branching (but not the degree of long branching) ) of the substantially linear polyethylene are comparable with highly branched high pressure low density polyethylene (LDPE) and are clearly distinct from ethylene polymers produced using Ziegler type catalysts, such as titanium complexes and ordinary catalysts to make homogeneous polymers, like hafnium or vanadium complexes. For the ethylene / α-olefin interpolymers, the long chain branching is greater than the short chain branching that results from the incorporation of the α-olefins into the polymer backbone. The empirical effect of the presence of long chain branching on the substantially linear ethylene / α-olefin interpolymers used in this invention manifests as increased rheological properties which are quantified and are expressed herein in terms of extrusion rheometry results of gas (GER) and / or melt flow, and increases of l / l2- In contrast to the term "substantially linear", the term "linear" means that the polymer lacks measurable or demonstrable long chain branches, ie a polymer is substituted with an average of less than 0.01 long chain branches / 1,000 carbon atoms. The substantially linear polyethylenes are further characterized by having: (a) a melt flow ratio, 1 / l2 > . from 5.63, (b) a molecular weight distribution, Mw / Mn as determined by gel permeation chromatography and defined by the equation: (Mw / Mn) < (I10 / I2) - 4.63, (c) a gas extrusion rheology such that the critical shear rate at the start of the melt surface fracture of the substantially linear ethylene polymer is at least 50 percent greater than the index of critical shear stress at the beginning of the melt surface fracture of the linear ethylene polymer, wherein the substantially linear ethylene polymer and the linear ethylene polymer comprise the same comonomer or comonomers, the linear ethylene polymer has a l2, Mw / Mn and a density within ten percent of the substantially linear ethylene polymer, and wherein the respective critical shear rates of the substantially linear ethylene polymer and the linear ethylene polymer are measured at the same melting temperature using a rheometer gas extrusion, and (d) a single melting peak of differential tracking calorimetry, DSC, -30 and 150 ° C. The determination of the critical shear rate and the critical shear strength with respect to the melt fracture, as well as other rheological properties, such as the rheological processing index (Pl), is performed using an extrusion rheometer of gas (GER). The gas extrusion rheometer is described by M. Shida, R.N. Shroff and L.V. Cancio in Polymer Engineering Science, Volume 17, No. 11, page 770 (1977), and in "Rehometers for Molten Plastics" by John Dealy, published by Van Nostrand Reinhold Co. (1982) on pages 97-99. Experiments are performed with gas extrusion rheometers at a temperature of 190 ° C, at nitrogen pressures between 250 to 5,500 psig (1.7 to 38 MPa) using a diameter of 0.0754 millimeters, a die with a diameter length ratio of 20 : 1 with an entry angle of 180 °. For the substantially linear ethylene polymers described herein, the rheological processing index is the apparent viscosity (in kpoise) of a material measured by gas extrusion rheometer at an apparent shear strength of 2.15 x 106 dyne / cm2 ( 0.215 MPa). Substantially linear ethylene polymers for use in the invention include ethylene interpolymers and have a rheological processing index in the range of 0.01 kpoise to 50 kpoise (0.01 to 50 kilograms / centimeter 'second), preferably 15 kpoise (15 kilograms / centimeter'second) or less. The substantially linear ethylene polymers used herein have a rheology processing index of less than or equal to 70 percent of the rheological processing index of the linear ethylene polymer (either a polymer polymerized by Ziegler or a uniformly linear branched polymer, as described by Elston in U.S. Patent Number 3,645,992) having one l2, Mw / Mn, and one density, each within 10 percent of the substantially linear ethylene polymers. The rheological behavior of the substantially linear ethylene polymers can also be characterized by the Dow Rheological Index (DRI), which expresses a "normalized relaxation time as a result of the long chain branching" of the polymer. (See, S. Lai and G.W. Knight ANTEC '93 Proceedings, INSITEMR Technology Polyolefins (SLEP) - New Rules in the Structure / Rheology Relationship of Ethylene a-Olefin Copolymers, New Orleans, La., May 1993). The Dow Rheology index values range from 0 for polymers that do not have any measurable long chain branching (such as, the Tafmer ™ products available from Mitsui Petrochemical Industries and Exact ™ and the Exact ™ products available from Exxon Chemical Company) to approximately 15 and they are independent of the fusion index. In general, for ethylene polymers of low to medium pressure (particularly lower densities) the Dow Rheological Index provides improved correlations to the melt elasticity and high shear flow capacity in relation to the correlations of the same tried with proportions of melt flow. For the substantially linear ethylene polymers useful in this invention, the Dow Rheological Index is preferably at least 0.1, and especially at least 0.5, and more especially at least 0.8. The Dow Rheological Index can be calculated from the equation: DRI = (3652879 x0 1 006 9 /? _- 1) 10 where x. is the characteristic relaxation time of the material and? 0 is the viscosity of zero shear stress of the material. Both x0 and? 0 are the "best fit" values for the Cross equation, as follows:? /? O = 1 / (1 + (? * T0) 1-n) where n is the index of power law of the material, and? Y ? are the viscosity and the shear stress measured, respectively. The determination of the viscosity baseline and the shear index data are obtained using a Rheometric Mechanical Spectrometer (RMS-800) under the dynamic scan mode from 0.1 to 100 radians / second at 160 ° C and a Rheometer Gas Extrusion (GER) at extrusion pressures from 1,000 psi to 5,000 psig (6.89 to 34.5 MPa), which corresponds to the shear strength from 0.086 to 0.43 MPa, using a diameter of 0.0754 millimeters, a die of length ratio to diameter 20: 1 to 190 ° C. The determinations of specific material can be made from 140 to 190 ° C as required to adjust the variations of the melting index. A graph of apparent shear strength versus apparent shear rate is used to identify the melt fracture phenomenon and quantify the critical shear rate and critical shear strength of the ethylene polymers. According to Ramamurthy in the Journal of Rheology, 30 (2), 337-357, 1986, about a certain critical flow index, the observed extrudate irregularities can be broadly classified into two main types: superficial melt fracture and fracture coarse cast Surface fracture of the melt occurs under seemingly stable flow conditions and varies in detail from loss of specular film brightness to the more severe form of "shark skin". Here, as determined using the gas extrusion rheometry described above, the onset of surface melt fracture (OSMF) is characterized at the beginning of extrusion gloss loss and which the surface roughness of the extrudate can only be detected by 40-fold expansion. The critical shear rate at the start of the melt surface fracture for substantially linear ethylene polymers is at least 50 percent greater than the critical shear rate at the start of the melt surface fracture of a linear ethylene polymer. which has essentially the same l2 and Mw / Mn. Coarse melt fracture occurs under unstable extrusion flow conditions and varies in detail from regular (for example, alternating roughness and smooth or helical surface) to random distortions. For commercial acceptability to maximize the performance properties of films, coatings and molds, surface defects should be minimal, if not absent. The critical shear strength at the start of the thick melt fracture for substantially linear ethylene polymers, especially those having a density greater than 0.910 grams / cm 3, used in the invention is greater than 4 x 106 dynes / cm 2 (0.4 MPa). Substantially linear ethylene polymers are known to have excellent processability, despite having a relatively narrow molecular weight distribution (ie, the Mw / Mn ratio is typically less than 2.5). Moreover, unlike homogeneously and heterogeneously branched linear ethylene polymers, the melt flow index (10/12) of the substantially linear ethylene polymers can be varied independently of the molecular weight distribution, Mw / Mn. In accordance with the foregoing, the core structure of the polymer (A) of the heteromorphic polymer compositions of the invention is preferably a substantially linear ethylene polymer. The heterogeneous polyethylenes that can be used as the heteromorphic long chain branching (B) in the practice of this invention fall into two broad categories, preparations with a free radical initiator at high temperatures and high pressure, and those prepared with coordination catalyst at high temperature and relatively low pressure. The former is generally known as low density polyethylene (LDPE) and is characterized by branched chains of polymerized monomer units that hang from the polymer backbone. Low density ethylene polymers have a density between 0.910 and 0.935 grams / cm3. Polymers of ethylene and copolymers prepared by the use of a coordination catalyst, such as a Ziegler or Phillips catalyst, are generally known as linear polymers because of the substantial absence of branched chains of polymerized monomer units hanging from the structure central. High density polyethylene (HDPE), generally has a density of about 0.941 to about 0.965 grams / cm3, is typically an ethylene homopolymer or an ethylene copolymer at low levels of a comonomer, and contains relatively few branched chains related to the different linear copolymers of ethylene and an α-olefin. High density ethylene polymers are well known, and are commercially available in various grades, and can be used in this invention. Linear copolymers of ethylene and at least one α-olefin of 3 to 12 carbon atoms, preferably 4 to 8 carbon atoms, are also well known and commercially available. As is well known in the art, the density of a linear ethylene / α-olefin copolymer is a function of both the length of the α-olefin, and the amount of the monomer in the copolymer related to the amount of ethylene, the greater the length of the α-olefin and the greater the amount of α-olefin present, the lower the density of the copolymer. The densities of these linear polymers generally vary from 0.87 to 0.91 grams / cm3. Both the materials made by free radical catalysts and coordination catalysts are well known in the art, as well as their methods of preparation. Linear heterogeneous ethylene polymers are available from The Dow Chemical Company as Dowlex ™ LLDPE resins and as Attane ™ ULDPE. The linear heterogeneous ethylene polymers can be prepared via the solution polymerization, slurry or gas phase of ethylene and one or more optional α-olefin comonomers in the presence of a Ziegler-Natta catalyst, by processes, such as those described in Patent of the United States of North America Number 4,076,698 for Anderson et al. The heterogeneous ethylene polymers are typically characterized by having molecular weight distributions, Mw / Mn, in the range of 3.5 to 4.1. Relevant discussions of both of these kinds of materials and their methods of preparation are found in U.S. Patent No. 4,950,541 and the patents to which it relates. The heterogeneous polymers are ethylene / α-olefin interpolymers characterized by having a linear central structure and a differential calorimetry (DSC) melting curve having a distinct melting peak greater than 115 ° C attributable to a high density fraction. The heterogeneous interpolymers will typically have an Mw / Mn greater than 3 (when the density of the interpolymer is less than 0.960 grams / cm3), and typically will have a branching index of composition distribution less than or equal to 50, which indicates that these Interpolymers are a mixture of molecules that have different comonomer contents and different amounts of short chain branching. Crystallinity with reference to an ethylene polymer is the well-known property of ethylene polymers. Several techniques have been developed to measure the crystallinity of the ethylene polymer. When the ethylene polymer is derived exclusively from hydrocarbon monomers (ie, when the ethylene polymer is a non-functionalized ethylene α-olefin interpolymer), the crystallinity can be determined from the density of the polymer using the following equation: % C = (p - pa) / p (pe - pa) x 100 wherein% C is the percent crystallinity of the ethylene polymer, pa is the density of an ethylene polymer having 0 percent crystallinity (ie, which is 100 percent amorphous) at room temperature (0.852 grams / cm3) ), eg represents the density of a polymer of ethylene at 100 percent crystallinity at room temperature (1,000 grams / cm3) and p represents the density of the polymer for which the percent crystallinity is being determined. The density can be determined according to ASTM D792, in which the samples are annealed at room temperature for 24 hours before the measurement is taken. The term "service temperature under load" (ULST), also known as "softening point under load" or "SPUL", means that the temperature at which penetration of the 1-millimeter probe into the polymer is achieved using a device capable of applying a constant effort of 1 N to a flat tip probe having a diameter of 1 millimeter, while raising the temperature of the polymer of 25 ° C at a rate of 5 ° C per minute under a nitrogen atmosphere. One of these devices is a Thermomechanical Analyzer (TMA), such as the Model TMA-7 made by the Perkin-Elmer Instrument Company. The procedure for carrying out this test is described in more detail in the Examples in the sections below. The higher density branching forming polymer (B) can have a wide range of molecular weights. On the low molecular weight side, the branched polymer will have an Mn of at least 2,000, preferably at least 3,000. On the side of the high molecular weight, the branched polymer will have a l2 of at least 0.05 grams / cm3. The physical melt indexes for the branched polymer vary from 0.05 to 40 grams / 10 minutes. When it is desirable to use branched polymer of a higher molecular weight, ie, a branched polymer having a l2 of less than 5 grams / 10 minutes, the increased number of branched polymer chain will require the presence of a higher concentration of the polymer branched, ie, amounts greater than 20 weight percent (or the use of higher levels of free radical indicator, ie, amounts greater than 0.5 weight percent) to produce a given increase in the low service temperature load. In contrast, when a branched polymer with a lower molecular weight is used, the presence of an increased number of shorter chains (which are preferably vinyl terminated) will cause an increase in the service temperature under load, despite the use of relatively small amounts of the branched polymer, that is, amounts as low as 5 percent by weight. While not wishing to be bound by theory, it is believed that in the case of lower molecular weight branched polymers, low concentrations thereof may be employed, since the heteromorphic polymer compositions will tend to have more than one small branching chain. slope of each central structure of the polymer. As shown in Figure 1, it is believed that the presence of more than one branch per molecule of central structure will tend to block the molecules of the central structure of the polymer from each other, which will provide structural integrity to the system despite the melting of the lower crystallinity polymer core structure material at higher usage temperature. Those skilled in the art of polymer science may consider many methods for producing heteromorphic compositions of the invention. In one embodiment, the higher crystallinity branching polymer and the lower crystallinity core structure polymer will be prepared by reacting previously prepared and isolated polymer reagents. In this case, the higher crystallinity branching polymer will react to form a T bond (by insertion) or an H bond (by light crosslinking) with the lower crystallinity core structure polymer. This reaction can be carried out by methods known to those skilled in the art. In a modality, hydrogen can be abstracted from the central structure of the polymer, and will react with the branched polymer. Methods for abstracting hydrogen from the polymer backbone include, but are not limited to, reaction with free radicals that are generated by hemolytic dissociation molecules (e.g., peroxide-containing compounds, or azo-containing compounds) or by radiation. The presence of olefinic unsaturation in the central structure polymer or the branched polymer can help control the location of insertion / crosslink sites. For example, the decomposition of peroxide in the presence of a larger fraction of a polymer with a saturated central structure and a smaller fraction of a vinyl-terminated branching polymer will tend to insert the branched polymer into the central structure polymer, while a polymer of Vinyl branching may undergo hydrogen attraction to produce a radical that will react with that of the central structure polymer to form H bonds. Branched polymers terminated in vinyl are prepared by adjusting reactor conditions, so that the polymerization chains are terminated by elimination of beta-hydride, instead of being terminated in hydrogen. In addition, coreactants, such as mono, di- or tri-allyl functional molecules (e.g., triazole cyanurate) can be used to further control the free radical processes. In general, insertion is preferred over light crosslinking, since more heteromorphic long chain qualifications can be incorporated without gelation. The use of a, O-dienes as a comonomer in the formation of polymers that form branches or polymers that form the core structure will increase the reactivity of that polymer component. Suitable a, O-dienes include 1, 7-octadiene and 1, 9-decadiene. When incorporated, these dienes will typically be presented in an amount less than 2 per polymer chain. The crosslinking or the insertion reactions can be carried out in a solution of the two polymers in a suitable solvent or in a mixture of melts of the polymer components. The last one is the preferred method. The melt mixture can be made in a batch mixer, such as the Brabender mixer, the Banbury mixer, the roll mill, or in a continuous mixer, such as a Farrel Continuous Mixer, or in a single or double screw extruder. . It is also possible to form a mixture of the polymers, then radiate or embed them with reactive solution (such as peroxide) and heat. However, the cast or mixture of solutions is preferred over these approximation forms. In an alternative embodiment, the compositions of the invention can be prepared by copolymerizing the branched polymer with monomers that make the core structure polymer. When a dual catalyst system is considered the central structure polymer and the present composition (ie, the heteromorphic polymer composition) could be copolymerized simultaneously. This method has the advantage of minimizing the phase outside the polymer with high Tg / Tm in a relatively cold reactor. In an alternative embodiment, the compositions of the invention can be produced in a series dual reactor arrangement, whereby the branched polymer is made in the first reactor and then fed into a second reactor, where it is copolymerized with the monomers forming the polymer of central structure to make the present composition. The second reactor should be maintained at a higher temperature, at which the branched polymer of higher crystallinity would be phase separated from the lower crystallinity core structure polymer. It is preferred that the reactor in which the copolymerization is carried out be a reactor with a high polymer concentration ("solids"), such as a cycle reactor, to maximize the concentration of the branching polymer with higher crystallinity polymerizable in the reactor. In a modality, a single-site catalyst will be employed to copolymerize branched polymers of higher crystallinity with ethylene and octene to produce ethylene / octene elastomers having high density polyethylene side chain branching. Single-site catalysts, particularly restricted geometry catalysts, are advantageous because they have a higher acceptability of high molecular weight monomers than traditional Ziegler catalysts or single-site catalysts of unrestricted geometry. Unlike cross-linking, copolymerization prevents gelation even at relatively high heteromorphic long-chain branching contents, since only one site of the long-chain branching is reactive. It is preferred that the high tm or Tg heteromorphic long chain branching precursor monomer have relatively low molecular weight and have at least one final olefin group per chain to aid in the copolymerization and dissolution of the monomer in solvent process and / or diffusion of the catalytic site. Optionally, a diene or polyene can be used as a comonomer in one or both polymers to improve the rate of incorporation / binding during copolymerization. For example, an ethylene-diene or propylene-diene copolymer could be produced in a reactor, then fed into a second reactor where it is copolymerized with ethylene and octene or ethylene and propylene. Provided that the diene level is relatively low, gelation can be avoided while increasing the rate of copolymerization of the heteromorphic branching precursor polymer and monomers of the core structure polymer. Preferably, when a diene or polyene is used as a comonomer, it will constitute less than 20 weight percent, more preferably less than 10 weight percent of the composition of the invention. In an alternative embodiment, the heteromorphic polymer composition can be mixed with one or more additional polymers having structure similar to the branched polymer or which can form a high part of Tm or Tg with solid via solution or co-crystallization. An example of this mixing component is a high density polyethylene. When the concentration of the branched polymer is low in the composition of the heteromorphic polymer, it may be necessary to provide additional polymer for the branches to co-crystallize or solidify in a phase in order to obtain the desired physical property and / or temperature resistance properties. An excess of the higher crystallinity polymer will be usefully co-crystallized with the higher crystallinity branches of the heteromorphic polymer composition, serving to increase the thickness of the sheets, which will tend to increase the crystalline melting temperature of the composition. polymer. In addition, this excess higher crystallinity polymer will serve to dot two separate higher crystallinity branches, which will raise the overall crystallinity of the heteromorphic polymer composition, which will increase the service temperature under charge. A preferred way to introduce the additional polymer is simply to add an excess of branched polymer to the reactor or to the fusion mixture, so that the copolymerization or the insertion or crosslinking is carried out, the excess unreacted branched polymer remains unreacted and it is available for co-crystallization or phase formation with the heteromorphic long chain branches. In another embodiment, the compositions of the invention can be used in mixtures with other polymers. For example, the compositions of the invention can be mixed with other polyolefins, such as heterogeneously branched linear ethylene / α-olefin ether polymers, homogeneously branched linear ethylene / α-olefin interpolymers, substantially linear ethylene / α-olefin interpolymers, ethylene / vinyl acetate copolymers, styrene block copolymers and amorphous polyolefins (such as polypropylene and polybutene). In a preferred embodiment, the heteromorphic polymer composition will include at least one component that contains polar fractions. That is, either the central structure polymer or the branched polymer will preferably be functionalized by inserting a polar fraction thereto. Any unsaturated organic compound that contains at least one site of ethylenic unsaturation (eg, at least one double bond), at least one carboxyl group (-COOH), and that will be inserted into an ethylene polymer as described above, is it can be used in the practice of this invention. As used herein, "carboxyl group" includes carboxyl groups per se and derivatives of carboxyl groups, such as anhydrides, esters and salts (both metallic and non-metallic). Preferably, the organic Company contains a site of ethylenic unsaturation conjugated with a carboxyl group. Representative compounds include maleic, acrylic, methacrylic, itaconic, crotonic, a-methyl crotonic, and cinnamic acid and their anhydrides, esters and derivative salts, and fumaric acid and its ester and derived salt. Maleic anhydride is the preferred unsaturated organic compound containing at least one ethylenic unsaturation and at least one carboxyl group. The unsaturated organic compound content of the inserted core polymer or branched polymer is preferably at least 0.01 weight percent, and more preferably at least 0.05 weight percent, based on the combined weight of the polymer and the organic compound. The maximum amount of unsaturated organic compound content may vary according to convenience, but typically does not exceed 10 percent by weight, preferably does not exceed 5 percent by weight, and more preferably does not exceed 2 percent by weight of the inserted polymer . The unsaturated organic compound can be inserted into the branched or desired polymer by any known technique, such as those taught in U.S. Patent Nos. 3,236,917 and 5,194,509. For example, in the '917 patent the polymer is introduced into a two-roll mixer and mixed at a temperature of 60 ° C. The unsaturated organic compound is then added together with free radical initiator, such as, for example, benzoyl peroxide, and the components are mixed at 30 ° C until the insertion is complete. In the '509 patent, the process is similar, except that the temperature of the reaction is higher, for example, 210 to 300 ° C, and the free radical initiator is not used or used at a lower concentration. An alternative and preferred method of insertion is taught in U.S. Patent No. 4,950,541, using a double screw devolatilizing extruder as the mixing apparatus. The ethylene polymer and the unsaturated organic compound are mixed and reacted within the extruder at temperatures at which the reactants are melted in the presence of a free radical initiator. Preferably, the unsaturated organic compound is injected into a zone maintained under pressure within the extruder. In the insertion of substantially linear ethylene polymers with, for example, maleic anhydride, it is described in U.S. Patent No. 5,346,963, incorporated herein by reference. In the preparation of the heteromorphic polymer compositions, it is recognized that the presence of a free radical initiator can lead to limited crosslinking of the adjacent central structure polymers, either directly to each other or via the attached branch. Provided that the level of these bonds is not sufficient to make the composition of the polymer unprocessable in thermoplastic manufacturing or extrusion processes, is within the scope of this invention. Preferably, the heteromorphic polymer compositions will have less than 30 percent gel, more preferably less than 10 percent gel, or more preferably less than 5 percent gel, and more preferably less than 2 percent gel. More preferably, the heteromorphic polymer compositions will be substantially free of gel. The heteromorphic polymers of the invention optionally may include antioxidants, fillers, extender oils, ultraviolet light stabilizers, anti-slip and antiblocking agents, pigments, dyes, or blowing agents, in accordance with the practice of those skilled in the art of polymeric formulation. When employed, the antioxidant is typically present in an amount less than 0.5 percent by weight, preferably less than 0.2 percent by weight, based on the total weight of the composition. The compositions of the invention can be usefully employed in hot melt adhesives and pressure sensitive adhesive formulations. In this regard, the compositions of the invention can be mixed with suitable amounts of one or more viscosifiers, one or more waxes, and / or one or more plasticizers. As used herein, the term "viscosity" means any of the hydrocarbon-based compositions useful for imparting viscosity to the hot melt adhesive composition. For example, various classes of viscosifiers include aliphatic resins of 5 carbon atoms, polyterpene resins, hydrogenated resins, aliphatic-aromatic mixed resins, rosin esters, and hydrogenated rosin esters. The viscosity employed will typically have a viscosity at 177 ° C, when measured using a Brookfield viscometer, of not more than 300 centipoise (300 grams / cm2), preferably not more than 150 centipoise (150 grams / cm2), and more preferably no more than 50 centipoise (50 grams / cm2). The viscosante employed will typically have a glass transition temperature greater than 50 ° C. Exemplary aliphatic resins include those available under the commercial designations Escorez ™, Piccotac ™, Mercures ™, Wingtack ™, Hi-Rez ™, Quintone ™, Tackirol ™, etc. Exemplary polyterpene resins include those available under the trade designations NirezMR, PiccolyteMR, WingtackMR, ZonarezMR, etc. Exemplary hydrogenated resins include those available under the commercial designations Escorez ™, Arkon ™, Clearon ™ etc. Exemplary aliphatic-aromatic resins include those available under the commercial designations Escorez ™, Regalite®, Hercures ™, ARMR, lmprez ™, Norsolene ™ M, Marukarez ™, Arkon ™ M, Quintone ™, etc. Other viscosifiers can be used, provided that they are compatible with the homogeneously linear or substantially linear ethylene / α-olefin interpolymer and the optional wax. The viscosity will typically be present in the hot melt adhesives of the invention in an amount less than 70 percent by weight, preferably less than 50 percent by weight. The viscosity will typically be present in the hot melt adhesives of the invention in an amount of at least 5 percent by weight, preferably at least 10 percent by weight. The term "wax" is used to refer to paraffinic homopolymer of crystalline ethylene or interpolymer or homogeneous ethylene polymers, which have an average number molecular weight of less than 6,000. Exemplary polymers that fall into this category include the ethylene homopolymers available from Petrolite, Inc. (Tulsa, OK) as Polywax ™ 500, Polywax ™ 1500 and Polywax ™ 2000; and the paraffin waxes available from CP Hall under the product designations 1230, 1236, 1240, 1246, 1255, 1260 and 1262. The PolywaxMR 2000 has a molecular weight of approximately 2000, an Mw / Mn of approximately 1.0, a density of 16 ° C of about 0.97 grams / cm 3, and a melting point of about 126 ° C. Paraffin wax CP Hall 1246 is available in CP Hall (Stow, OH). Paraffin wax CP Hall 1246 has a melting point of 62 ° C, a viscosity of 99 ° C of 4.2 centipoise (4.2 grams / csec), and a specific gravity at 23 ° C of 0.915.

Preferred waxes are prepared using a constrained geometry catalyst. These polymers will be either ethylene homopolymers or ethylene interpolymers and a comonomer, as presented above with respect to polymer one, for example, α-olefins of 3 to 20 carbon atoms, styrene, styrene substituted by alkyl, tetrafluoroethylene, vinylbenzocyclobutane, non-conjugated dienes, and naphthenics. These polymers, in comparison with traditional waxes, will have an Mw / Mn of from 1.5 to 2.5, preferably from 1.8 to 2.2. These polymers are described and claimed in U.S. Patent Application Serial Number 784,683, filed January 22, 1997 (WO 97/01181). The wax will have an average number molecular weight less than 6,000, preferably less than 5,000. These waxes typically have a number average molecular weight of at least, preferably at least 1,300. The wax useful in the hot melt adhesives of the invention, when it is an ethylene homopolymer (either a traditional ethylene homopolymer wax or an ethylene homopolymer prepared with a catalyst of restricted geometry), or an ethylene interpolymer and a comonomer selected from the group consisting of α-olefins of 3 to 20 carbon atoms, non-conjugated, and naphthenic dienes, will have a density of at least 0.910 grams / cm 3. These second polymers will have a density of not more than 0.970 grams / cm3, preferably not more than 0.965 grams / cm3. The heteromorphic polymeric compositions of the invention are useful for use in pressure sensitive adhesive formulations, because the higher crystallinity branching polymer serves to improve the closing time of the adhesive. As the adhesive cools, the branched polymer crystallizes while the core polymer remains soft and / or flowable. This imparts resistance to the adhesive during the fixing process and decreases the opening / closing time. The hot melt adhesive (particularly pressure sensitive adhesive) may further comprise an oil or other plasticizer, such as an amorphous polyolefin. The oils are typically used to reduce the viscosity of the hot melt adhesive. When employed, the oils will be present in an amount of less than 25, preferably less than 15, and more preferably less than 10 weight percent, based on the weight of the hot melt adhesives. Exemplary classes of oils include white mineral oil (such as Kaydol ™ oil (available from Witco), and Shellflex® 371 naphthenic oil (available from Shell Oil Company). To the extent that the oil decreases the adhesive character of the hot melt adhesive At levels detrimental to the intended use, it should not be used The hot melt adhesives of the invention can be prepared by standard melt blending procedures, in particular, the heteromorphic polymer composition, the optional glidant, the optional wax, and the plasticizer Optionally, melts can be mixed at an elevated temperature (150 to 200 ° C) under a cover of inert gas until a homogeneous mixture is obtained.Each mixing method that produces a homogeneous mixture without degrading the hot melt components is satisfactory, such as through the use of a heated container equipped with an agitator. heteromorphic rich, optional wax, optional plasticizer, and optional plasticizer may be provided to an extrusion coater for application to the substrate. Suitable pressure sensitive adhesives will exhibit a probe viscosity of at least 200 grams, more preferably at least 300 grams, and more preferably at least 350 grams. Suitable pressure sensitive adhesives will also exhibit a heat resistance that is at least 10 ° C, preferably at least 15 ° C, and more preferably at least 20 ° C more than that of pressure sensitive adhesives, in which the branched polymer and the core polymer are used in a mixture other than the form of the heteromorphic polymer compositions of the invention. Suitable adhesives will be of a sufficiently low viscosity to allow easy application on the desired substrate. Typically, hot melt adhesives will have a melt viscosity at 177 ° C, which is less than 50,000 centipoise (50,000 grams / cm2), with lower viscosities being typical most preferred. The applications of the heteromorphic polymeric compositions of this invention (particularly those in which at least one polymer of central structure or the branched polymer is functionalized with a polar portion) will also include, but are not limited to, packaging such as those of automotive windows. , sealants, adhesives, flexible molded goods, such as shoe soles, cables and cable insulation and coating, roofing membranes, floor coverings, hoses, boots, automotive parts, and other parts known to the industry that require elastomeric materials with adhesion to polar substrates. The following Examples, which present representative heteromorphic polymer compositions of the invention, are provided for the purpose of illustration, rather than limitation.

Polymers Employed in the Preparation of the Compositions of the Examples Polymer A1 - a substantially linear octene / ethylene copolymer prepared according to the teachings of U.S. Patent No. 5,278,236, which had a measured l2 of 0.94 grams / 10 minutes, and a density of 0.869 grams / cm3. Polymer A2 - a substantially linear ethylene / octene copolymer prepared in accordance with the teachings of U.S. Patent No. 5,278,236, which had a measured l2 of 3.86 grams / 10 minutes, and a density of 0.867 grams / cm3 . Polymer A3 - a substantially linear ethylene / octene copolymer prepared in accordance with the teachings of U.S. Patent No. 5,278,236, which had a measured l2 of 23.79 grams / 10 minutes, and a density of 0.867 grams / cm3 . Polymer A4 - a substantially linear ethylene / octene copolymer prepared according to the teachings of U.S. Patent Number 5,278,236, which had a measured l2 of 30 grams / 10 minutes, and a density of 0.870 grams / cm3 . Polymer A5 - a substantially linear ethylene / octene copolymer prepared in accordance with the teachings of U.S. Patent No. 5,278,236, which had a density of 0.870 grams / cm3 and one l2 of 18 grams / 10 minutes. Polymer A6 - a substantially linear ethylene / octene copolymer prepared according to the teachings of U.S. Patent No. 5,278,236, which had a measured l2 of 1 gram / 10 minutes and a density of 0.855 grams / cm3. Polymer A7 - a substantially linear ethylene / octene copolymer prepared in accordance with the teachings of U.S. Patent No. 5,278,236, which had a density of 0.855 grams / cm 3, and a melt index of 30 grams / 10 minutes Polymer A8 - is an ultra low molecular weight ethylene / 1-ketene copolymer prepared in accordance with the teachings of U.S. Patent Application Serial Number 784,683, filed January 22, 1997 (WO 97) / 01181), which has a density of 0.855 grams / cm3, and a melt viscosity at 177 ° C of 350 centipoise (350 grams / cpvsecond). Polymer A9 - is a substantially linear ethylene / 1-ketene copolymer prepared in accordance with the teachings of U.S. Patent No. 5,278,236, which had a density of 0.855 grams / cm3, and a melt index of 0.5 grams / 10 minutes. Polymer A10 - is a substantially linear ethylene / 1-ketene copolymer prepared in accordance with the teachings of U.S. Patent No. 5,278,272, which had a density of 0.870 grams / cm3, and a melt index of 30. grams / 10 minutes. Polymer B1 - HDPE 55500 high density ethylene polymer - is an ethylene / butene copolymer supplied by Phillips Petroleum, which had a measured l2 of 49 grams / 10 minutes, and a density of 0.955 grams / cm3.

Polymer B2 - Marlex 50-100, high density polyethylene that has a density of 0.952 grams / cm3, and a l2 of 0.08 grams / 10 minutes, available from Phillips. Polymer B3 - Dowlex 25355, high density polyethylene having a density of 0.955 grams / cm3, and a l2 of 25 grams / 10 minutes. Polymer B4 - Dowlex 25455, high density polyethylene having a density of 0.955 grams / cm3, and one l2 of 25 grams / 10 minutes. Polymer B5 - a substantially linear ethylene / 1-octene copolymer prepared in accordance with the teachings of U.S. Patent No. 5,278,236, which had a density of 0.902 grams / cm3, and a melt index of 30 grams /10 minutes. Polymer B6 - a substantially linear ethylene / 1-ketene copolymer prepared in accordance with the teachings of U.S. Patent No. 5,278,236, which had a density of 0.913 grams / cm 3, and a melt index of 30 grams / 10 minutes. Polymer B7 - Attane ™ 6152, ultra low density polyethylene, a linear heterogeneous ethylene / 1-ketene copolymer having a density of 0.904 grams / cm3, and a melt index of 0.5 grams / 10 minutes. Polymer B8 - an ultra low molecular weight ethylene / 1-octene copolymer prepared in accordance with the teachings of U.S. Patent Application Serial Number 784,683, filed January 22, 1997 (WO 87) / 01181) having a density of 0.955 grams / cm3, and a melt viscosity at 177 ° C of 5,000 centipoise (5,000 grams / cm2). Polymer B9 - Dow HDPE 12165 high density polyethylene, which has a density of 0.955 grams / cm3, and a melt index of 1.0 grams / 10 minutes. Polymer B10 - Dow HDPE 25355 high density polyethylene, which has a density of 0.955 grams / cm3, and a melt index of 10 grams / 10 minutes. Polymer C - a reactor polymer mixture prepared according to the process of WO 94/17112, having as its objective composition: 68.5 weight percent of a substantially linear ethylene / octene copolymer having a density of 0.861 grams / cm3 and one l2 of 0.29 grams / 10 minutes, and 31.5 weight percent of a high density polyethylene that has a density of 0.946 grams / cm3 and a l2 of 370 grams / 10 minutes. Polymer D - a high density polyethylene inserted with maleic anhydride having a density of 0.953 grams / cm3, a melting point of 9 grams / 10 minutes, and 1.2 weight percent of maleic anhydride prepared by the reactive extrusion of polyethylene high density that has a density of 0.953 grams / cm3 with maleic anhydride.

Lupersol 500R (99 percent pure dicumulium peroxide, available from Elf Atochem). Lupersol-130 (90 to 95 percent 2,5-dimethyl-2,5-di (t-butylperoxy) hexin-3, available from Elf Atochem). Lupersol-101 2,5-dimethyl-2,5-di (t-butylperoxy) hexane (available from Elf Atochem).

Test Methods Used to Evaluate Compositions of the Examples and Comparative Examples The service temperature under load (ULST) was measured using a thermomechanical analyzer (TMA). Penetration against temperature was measured. The temperature at the penetration of the 1 millimeter probe was taken as the softening temperature under load. A heating regime of 5 ° C / minute and a load of 102 grams was used. A Rheometric Model Solids Analyzer was used RSAII to determine the change in modules with respect to temperature. Film samples of approximately 0.25 millimeters thick were compression molded holding 1500 psi (10.3 MPa) and 177 ° C for 5 minutes, and then cooling to -2.8 ° C / minutes) up to 32 ° C. The samples were kept at 32 ° C for 1 minute, and then removed from the press. A specimen of approximately 0.25 x 4.4 x 22 millimeters was cut, then tested under the following conditions: frequency of 10 rad / second in the rectangular torsion test, starting at -145 ° C and increasing to 120 ° C or 150 ° C or 270 ° C at a step size of 5 ° C with a soak time of 30 seconds for each step, under a nitrogen atmosphere. The gel content was determined by xylene extraction in accordance with ASTM D 2785, Procedure A. Tension and strain were measured at 23 ° C and 70 ° C in accordance with ASTM D-1708. The values in parentheses are tension and distension at 70 ° C. Shore A hardness was measured according to ASTM D2240. The ultimate tensile strength was measured according to ASTM D-1708 using microtensile rods. The melt viscosity was determined according to the following procedure using a Brookfield Laboratories DVII + Viscometer in disposable aluminum chambers for the samples. The spindle used is a SC-31 hot melt spindle, suitable for measuring viscosities in the range of 10 to 100,000 centipoise (10 to 100,000 grams / cpvsecond). A cutting knife was used to cut the samples into pieces small enough to fit into the sample chamber 2.5 centimeters wide, 12.5 centimeters long. The sample was placed in the chamber, which in turn was inserted into the Brookfield Thermosel and locked in place with bent needle nose pliers. The sample chamber has a protrusion in the bottom that fits the bottom of the Brookfield Thermosel to ensure that the camera can not rotate when the spindle is inserted and rotated. The sample was heated to 177 ° C, adding additional sample until the molten sample was approximately 2.5 centimeters below the top of the sample chamber. The viscometer apparatus was lowered and the spindle was immersed in the sample chamber. The apparatus was continued under the apparatus until the viscometer clips were aligned on the Thermosel. The viscometer was turned on, and set to a shear limit which led to a torque reading in the range of 30 to 60 percent. Readings were taken every minute for approximately 15 minutes, or until the values were stabilized, whose final reading was recorded.

EXAMPLES 1-3: Determination of the Amount of Branched Polymer Reacting in the Formation of Heteromorphic Polymer Compositions of the Invention A Haake Rheocord System 40 torque rheometer was used with a Rheomix 600 mixer and roller style mixing blades to prepare the compositions of these Examples. The mixtures were prepared by mixing the components at 75 revolutions per minute at 145 ° C. The compositions of Polymers A2, A3 and B were presented above. The Lupersol 500 (99 percent pure dicumyl peroxide, available from Elf Atochem) was added in the indicated amount and the resulting mixture was mixed for about 1 minute at 145 ° C, the temperature was raised to 175 ° C, and the sample was mixed for a total of 15 minutes. The samples were placed on a cold compression molding plate while still hot, and compressed to a thin film for FTIR analysis of the vinyl content. The FTIR analysis of representative compositions of the invention is presented in Table 1.

Table One. Vinyl Analysis of Examples 1-3 The reduction in the concentration of the final vinyl group can be considered in an indication of the degree to which "T" bonds were formed. Since the hydrogen extractability of Polymer A2 and A3 can be assumed to be approximately as likely as the hydrogen extractability of Polymer B1, since most of the vinyl groups are in Polymer B1 of lower molecular weight than in the Higher molecular weight A2 and A3 polymers (since a 50:50 mixture of the polymer components was used), it can be assumed that approximately 50 percent of the "T" bonds formed were due to the insertion of the Polymer B1 in Polymers A2 and A3. The sharp reduction in vinyl concentration shown in Table One is additional evidence of the formation of "T" bonds. The attachment of Polymer B1 of higher crystallinity on the core structure is supported by the remarkable improvement in temperature resistance as described in the following examples.

Examples and Comparative Examples 4-18: Improvement in Temperature Resistance Presented by the Heteromorphic Polymer Compositions of the Invention A Haake torque rheometer was used Rheocord System 40 with a Rheomix 3000E mixer and roller style mixing blades. The samples were prepared by mixing the melt of Polymer B1, and the applicable Polymers A1, A2 and A3 resin, together at 60 to 75 revolutions per minute and at about 145 ° C for about 4 minutes. Lupersol 500R (99 percent pure dicumyl peroxide, available from Elf Atochem) was added in the indicated amount. The speed of the mixer was raised to about 160 revolutions per minute to mix rapidly in the peroxide, thereby causing a viscous heating effect, which, after the course of 1-2 minutes, raised the temperature of the mixture to approximately 190. ° C, causing the decomposition of peroxide. The speed of the mixer was reduced to 60 revolutions per minute for an additional minute. After mixing, the mixer was stopped and the sample was removed and allowed to cool. The pieces of polymer were then granulated.

Table Two or - * The maximum temperature is the appropriate temperature where the RSA module (E ') of the curve falls below 106 dynes / cm2 (0.1 MPa). Some of the first samples tested were only tested at 120 ° C. If there were no failures, this was indicated with > 120 Table Two shows that the mixture of Comparative Example 15, ie, the mixture that was not subjected to the peroxide treatment, failed at about 70 ° C. Due to the fusion of the crystallites of Polymer A3, the mixture did not have sufficient strength to maintain its integrity in the Rheometric Solids Analyzer test and the sample specimen was broken. In contrast, the heteromorphic polymer composition of Example 15, that is, the composition that was subjected to the peroxide treatment, maintained its integrity up to 130 ° C, which is approximately the melting point of Polymer B1. Table Two summarizes the results of a series of comparative mixing compositions (prepared without peroxide treatment), and a series of heteromorphic polymer compositions of the invention (prepared with peroxide treatment). Table Two shows that the heteromorphic compositions of the invention had a significantly improved temperature resistance compared to the comparative mixtures. In addition, Table Two shows that the pure Polymers A1, A2 and A3, which were treated with peroxide, additionally failed at relatively low temperatures. Thus, the substantial improvement in temperature resistance for the heteromorphic polymer compositions of the invention can not be attributed to the formation of a crosslinked network, but is hence attributable to the annexation of the branches of Polymer B1 in the course of high melting point on the central structure formed by Polymers A1, A2 and A3.

Examples 19-23: Effect of Peroxide on the Physical Properties of the Heteromorphic Polymer Compositions The heteromorphic polymer compositions of the Comparative Examples and Examples 19-23 were prepared according to the procedures presented above in Examples 1-4. The compositions of the heteromorphic polymer compositions and the comparative samples, and the resulting properties are presented in the following Table Three.

Table Three You Discussion of Examples 19-21. With respect to Examples 19-21, as the amount of peroxide is increased, the operating temperature under load in the same way increases, by 27 ° C in the case of Example 20, and 47 ° C in the case of Example 21. The results shown in Table Three show that the heteromorphic polymer compositions of the invention of Examples 20 and 21 have a much higher heat resistance than the corresponding comparative mixture of Comparative Example 19. This is presented in Figure 3, which shows that the heteromorphic polymer compositions of Examples 20 and 21 withstand a temperature before Shore A hardness falls below 45 compared to Comparative Example 19. This is further shown in Figure 4, which shows that heteromorphic polymer compositions of Examples 20 and 21 suffer a probe penetration of 1 millimeter at higher temperatures than does Comparative Example 19. Table Three further indicates that the heteromorphic polymer compositions have tensile properties at elevated temperatures that exceed those of the comparative blends of Comparative Example 19. For example, the mixture of Comparative Example 19 loses most of its tensile strength at 70 ° C. In contrast, the heteromorphic polymer compositions of Examples 20 and 21 exhibit a 100 ° C tensile strength of 250 psi (1.72 MPa) and 180 psi (1.24 MPa), respectively. Moreover, the gel contents of the heteromorphic polymer compositions of Examples 20-21 are lower than those of the partially cross-linked mixtures of the prior art, see, for example, US Pat. No. 3,806,558, which describes a gel content greater than 30 percent. It is surprising that heteromorphic polymer compositions exhibit such a large improvement in properties at high temperatures without a large reduction in flexibility and softness, and without the formation of significant amounts of crosslinked network structure.

Discussion of Examples 21-23. With respect to Examples 21-23, the service temperature under load increased as the concentration of branching polymer against higher crystallinity increased. It is interesting to note that between Examples 23 and 21, an increase in the amount of the higher crystallinity material from 20 to 25 weight percent produced an increase in the service temperature under load of 40 ° C.

Discussion of Examples 24-25. Examples 24 and 25 illustrate the fact that mixtures of the higher crystallinity polymer and the lower crystallinity polymer were beneficially produced in the reactor with heteromorphic compositions of the invention. It is noted that the heteromorphic polymer composition of Example 25 had an operating temperature under load that was 40 ° C higher than that of the mixture that did not react in the reactor of Comparative Example 24.

Electron Micrograph Analysis of Electron Transmission (TEM) of the Heteromorphic Polymer Compositions of the Examples and Comparative Examples 19-20 and 24-25 Heteromorphic polymer compositions and comparative mixtures were compression molded into disks with dimensions of 2.5 centimeters in diameter inside and 0.16 centimeters thick at a molding temperature of 177 ° C, then cooled to 22 ° C at a rate of 15 ° C / minute before demolding. Thin strips of the compression molded samples were immersed in Epofix (Struer epoxy-based immersion set) at room temperature. After trimming the blocksThese were stained in a mixture of ruthenium trichloride and CloroxMR bleach for two hours at room temperature. Ultra-thin sections of approximately 1,000 angstroms in thickness were harvested at room temperature using a Reichert-Jung Ultracut E microtome. The sections were placed in formvar-coated copper grooves. The sections were seen using a JEOL 2000FX TEM operated at 100 kV, accelerating voltage and a magnification of 30,000 times. The digital analyzes of the TEM images were performed on a Leica Quantimet 570 brightness scale analyzer. The grayscale images were imported through a CCD camera with amplifier gain and setting the zero individually for each image. The binary images containing the scattered phase and the individual sheets were created by gray scale threshold. These binaries were opened morphologically with horizontal and vertical operators of size 1 to remove the individual sheets of the matrix. The background noise was removed by a morphological opening with a size 2 disc. Manual editing was performed to correct residual errors. For a description of the image transformation used, see "Image Analysis and Mathematical Morphology", Volume 1, by Jean Serra, Academic Press (1982). The digital image analyzer measured eight diameters in each scattered phase and a fraction of the total area of the binaries. Statistical diameters of the average diameter of each dispersed phase were calculated. These statistical diameters conveyed information about the size of the phase and the amplitude of the size distribution. The diameter of the weighted volume mean emphasized the presence of large characteristics, while the diameter of the harmonic mean emphasized the small characteristics. The TEM image of Comparative Example 19 is shown in Figure 5, at an extension of 30,000 times. The micrograph shows a two-phase morphology consisting of polyethylene domains of higher density dispersed in a continuous matrix of elastomer phase attributable to Polymer A3. The domains attributable to the higher density polyethylene component of Polymer B2 are distinguished by their laminar morphology, both inside and radiating outward toward the matrix. The elastomer phase attributable to the lower density polyethylene component of Polymer A3 shows the characteristic granular morphology of the marginal micelle crystallites. In comparison, the TEM image of the heteromorphic polymer composition of Example 20 is shown in Figure 6, at an amplification of 30,000 times. While the micrograph shows a two-phase morphology, the average domain size of the dispersed higher density polyethylene phase attributable to Polymer B2 is significantly reduced over that of Figure 5. The good dispersion of the sheets in the phase of The elastomer is consistent with the belief that the higher density polyethylene component of Polymer B2 is inserted into the central structure of the elastomer formed by Polymer A3. The TEM images of Comparative Example 24 and Example 25, at an enlargement of 30,000 times, are presented in Figures 7 and 8. The volume fraction of the dispersed high density polyethylene phase was determined by digital image analysis. The volume and size of the dispersed phase of the high density polyethylene in the comparative blends and in the heteromorphic polymer compositions is presented in the following Table Four: Table Four As noted in Table Five, the heteromorphic polymer compositions of Example 20 of the invention exhibited more than 50 percent fewer islands of higher crystallinity (as evidenced by a significantly lower percentage by volume) than mixtures that did not react of the Examples Comparatives 19. Similarly, the heteromorphic polymer compositions of Example 25 of the invention exhibited 67 percent fewer islands of higher crystallinity (as evidenced by the significantly lower percent by volume) than the unreacted mixtures of the Comparative Examples 24. This suggests that the heteromorphic compositions of the invention in fact comprise core structures of elastomer, to which the higher density polymer component has been inserted.

An average volume percent of Comparative Examples 19 and 24 is 22.1 percent. The average volume percent of Examples 20 and 25 is 8. Based on this, it is estimated that 64 percent of the total high density polyethylene is inserted into the central structure of the elastomer.

Examples 26 and 27: Heteromorphic Ethylene Polymers for Pressure Sensitive Adhesives The following polymers are used to prepare heteromorphic polymer compositions of this example: Samples were prepared by mixing the melt of Polymers A6 and D in the amounts indicated in the Haake Rheocord System 40 torque rheometer with a Rheomix 3000E mixer and roller style blades at 60 to 75 revolutions per minute, and approximately 145 ° C for approximately 4 minutes. Lupersol ™ 101 (available from Elf Atochem) was added in the indicated amount, and the speed of the mixer was raised to about 160 revolutions per minute to mix rapidly and cause a viscous heating effect, and over the course of 1 to 2 minutes, the temperature was raised to about 190 ° C to decompose the peroxide. The speed of the mixer was reduced to 60 revolutions per minute for an additional minute. Following the mixture, the mixer was stopped and the sample was stirred and allowed to cool. The pieces of polymer were then granulated.

The resultant heteromorphic polymers and the comparative polymer blend were tested to see if it acts as a pressure sensitive adhesive for tape. The following formulations were used for adhesive: 100 phr of resin, 220 phr of Escorez 1310 LC viscosante, and 1 phr lrganoxMR 1010. The components of the formulation were mixed molten at 130 ° C in a Haake. After reaching a uniform mixture, it was added to 80 phr of Kaydol oil and to a syringe. Samples of the tape were prepared by compression molding the adhesives formulated between Mylar ™ films and release sheet at 170 ° C under 20,000 psi (138 MPa) pressure. The resulting thickness of the adhesive was approximately 0.05 millimeters. The heat resistance of the formulated adhesive was measured using a RDA-II dynamic mechanical spectrometer from Rheometrics, Inc. The temperature at which the storage module (G ') of the rubber plate suddenly decreased and was taken as the resistance temperature. heat. The temperature sweep was carried out from about -70 ° C to 200 ° C at a step of 5 ° C with 30 seconds of equilibrium delay in each step. The oscillatory frequency was 1 radian / second with a self-distension function of 0.1 percent distension initially, increasing in positive settings of 100 percent, provided that the torque was reduced to 4 grams-centimeters. The maximum distension was fixed at 26 percent. Parallel plate adjustments of 7.9 millimeters were used with an initial hole of 1.5 millimeters at 160 ° C (the sample was inserted into the Rheometric RDA-II solids analyzer at 160 ° C). The "KEEP" function was used at 160 ° C, and the instrument was cooled to -70 ° C, and the test started, which was corrected to see thermal expansion or shrinkage as the test chamber heated or cooled. A nitrogen environment was maintained throughout the experiment to minimize oxidative degradation. The viscosity in the probe was measured according to ASTM D-2979-71, using a momentary dwell time of 10 seconds and a probe separation rate of 1 centimeter / second. The viscosity at 177 ° C was measured according to the following procedure using a DVII + Viscometer from Brookfield Laboratories in disposable aluminum sample chambers. The spindle used is a SC-31 hot melt spindle. Samples were cut into pieces small enough to fit into the sample chamber 2.5 centimeters wide, 12.5 centimeters long. The sample was heated to 177 ° C, with the molten sample about 2.5 centimeters below the top of the sample chamber. The viscometer apparatus was lowered and the spindle was immersed in the sample chamber. The viscometer was turned on, and set at a shear rate which led to a torque moment reading in the range of 30 to 60 percent. Readings were taken every minute for approximately 15 minutes, or until the values were stabilized, whose final reading was recorded.

The heteromorphic polymer compositions and the comparative polymers, the properties thereof, and their performance as pressure sensitive adhesive formulations, are presented in Tables Five through Seven.

Table Five 1 The results in Table Five indicate that the heteromorphic polymers can be used as a pressure sensitive adhesive. The sample has acceptable processability, probe viscosity (comparable to commercially available Scotch Magical Tape), and a higher service temperature than the comparative mixture.

Table Six Composition of the Compositions of Heteromorphic Polymer 26-39 Table Seven Pressure Sensitive Adhesives You * All formulations were stabilized with 1 phr Irganox ™ 1010 phenolic hindered (available from Ciba Geigy).

The TMA data presented in Table Seven suggest that the higher service temperature of the heteromorphic polymer compositions is higher than the non-inserted comparative samples. Compare, for example, Examples 21-2 to 21-3, and 21-4 to 21-5. The results of the probe viscosity suggest that the compositions of the invention have acceptable viscosity, that is, probe viscosity values of at least 200 grams, and more preferably of at least 300 grams, and more preferably of at least 380 grams. The data G 'and Tg suggest that the heteromorphic polymer compositions can be used in pressure sensitive adhesive formulations, that is, they are characterized to have G' of 105 to 106 dynes / cm2 and a Tg from -10 to 10 ° C. The Examples in Table Seven show the flexibility of the technology of this invention, that is, the molecular weight and the density of the core structure polymer and the branched polymer can be changed to make the compositions suitable for use in the variety of applications of pressure sensitive adhesives.

Examples 40-41: Functionalization to Improve Glass Adhesion Samples were prepared by extruding reagent from Polymers A10 and B4 (in the case of Example 40) and Polymer A10 and D (in the case of Example 41). In each case, the mixture of the reagents of the polymer was embedded with peroxide, and the submerged sample was extruded in a twin screw extruder at 210 ° C. The resulting compositions were evaluated for superior service temperature, nap shear adhesion, and T-peel shear adhesion. Napa shear adhesion was determined by compression molding the test resin at 177 ° C between two glass microscope slides, supporting the slides with sponge tape, then performing a nap shear pull test on a Instron tensiometer. The T-Peel Shear Stress Adhesion was determined as follows. The glass slides (dimensions: 7.6 x 2.5 x 0.12 centimeters from Fisher Scientific) were glued onto cold rolled steel strips (CRS, dimensions: 15 x 2.5 x 0.08 from Q-Panel Company) using Loctite Depend Adhesive (Article No. 00206 , from Loctite Corporation) by placing a surface activator on the cold rolled steel strip and adhesive resin on the glass side. Sufficient mixing of the adhesive was presented when the glass slide and cold rolled steel strip were placed together. These bonded joints were held together with a weight of 22 kilograms for 10 minutes. Cold rolled steel / glass strips were placed on a hot plate (180 ° C). The HDPE-g-EO test polymers and a second metal strip were placed on the cold rolled steel / glass strips resident in the hot plate. They were heated until the polymer sample melted. They were then cooled to room temperature. These test specimens were tested 24 hours after preparation. The voltage-distension nominal diagrams were generated using an Instron 4204 Material Test System in accordance with the ASTM method D1876-72. The distance between the azideras was 5 centimeters, and the speed against machine was 25 centimeters per minute. The heteromorphic polymer compositions and the resulting properties are presented in the following Table Eight.

Table Eight The adhesion to the glass of the heteromorphic polymer composition significantly increases when used in the MAH-g-HDPE instead of HDPE as the branched polymer. The results in Table Eight show that the heteromorphic composition injected MAH-g-HDPE has much higher nap shear adhesion than the T-peel shear bond to glass than the non-functionalized heteromorphic polymer composition. As discussed above in the discussion of adhesive formulation 21-9, heteromorphic polymer compositions functionalized with maleic acid can be usefully employed in pressure sensitive adhesive formulations.

The present invention, having been fully described and exemplified in detail above, will be limited only in accordance with the following claims.

Claims (16)

1. A heteromorphic polymer composition characterized in that it comprises: (a) a central structure derived from a polymer of central structure, which is a linear or substantially linear homogeneous ethylene / α-olefin interpolymer; and (b) a branch that is attached to the central structure, said branch being derived from a branching polymer, said branching polymer is an ethylene homopolymer or ethylene / α-olefin interpolymer having a density that is less 0.004 g / cm3 greater than the polymer with a central structure and having a higher crystallinity than that of the polymer with a central structure. The heteromorphic polymer composition of claim 1, wherein the core structure is derived from a polymer of central structure, which is a linear or substantially linear homogeneous ethylene / α-olefin interpolymer having a density less than 0.920 g / cm3. The heteromorphic polymer composition of claim 1, wherein the branching is characterized in that it is derived from an ethylene homopolymer or an ethylene / α-olefin interpolymer having a density that is at least 0.006 grams / cm 3 greater than the one of the central structure. The heteromorphic polymer composition of claim 1, wherein the polymer backbone is further characterized in that it is derived from a linear or substantially linear homogeneous interpolymer of ethylene and at least one α-olefin of 3 to 20 carbon atoms. The heteromorphic polymer composition of claim 4, wherein the linear or substantially linear homogeneous interpolymer of the core structure is further characterized by having a branching index of compositional distribution of at least 50 and one Mw / Mn less than 3. The heteromorphic polymer composition of any of the preceding claims, wherein the interpolymer of the core structure is characterized in that it is derived from a substantially linear polymer characterized by having: (a) a melt flow ratio, ._ / 12 L of 5.63, (b) a molecular weight distribution, Mw / Mn as determined by gel permeation chromatography and defined by the equation: (Mw / M ") < (I.0 / I2) - 4.63, (c) a gas extrusion rheology such that the critical shear rate at the beginning of the melt surface fracture of the substantially linear ethylene polymer is at least 50 percent greater than the critical shear rate at the beginning of the melt surface fracture of the linear ethylene polymer, wherein the substantially linear ethylene polymer and the linear ethylene polymer comprise the same comonomer or comonomers, the linear ethylene polymer has a l2, Mw / Mn and a density within ten percent of the substantially linear ethylene polymer, and wherein the respective critical shear rates of the substantially linear ethylene polymer and the linear ethylene polymer are measured at the same melting temperature using a gas extrusion rheometer, and (d) a single differential scanning calorimetry melting peak, DSC, -30 and 150 ° C. The heteromorphic polymer composition of any of the preceding claims, wherein the interpolymer of the core structure is characterized in that it is derived from a substantially linear interpolymer of ethylene / α-olefin which is substituted with an average of 0.01 to 3 branches of long chain / 1,000 carbon atoms. 8. A heteromorphic polymer composition characterized by comprising a reaction product of (a) from 40 to 5 percent by weight of a branching polymer, the branching of which comprises an ethylene homopolymer or an ethylene / α-olefin interpolymer , and (b) from 60 to 95 weight percent of a material forming a core structure, which is ethylene and one or more comonomers, or which is a homogeneous linear or substantially linear ethylene / α-olefin interpolymer.; and wherein the crystallinity the resulting branch is at least 5 percent greater than the crystallinity of the resulting core structure; and wherein the heteromorphic polymer composition has a higher service temperature that is at least 10 ° C higher than the unreacted mixture of the resulting branching polymer polymer of the resulting core structure. 9. A heteromorphic polymer composition of any of the preceding claims, characterized by comprising fractions derived from the insertion of a polar fraction in at least one polymer of central structure or the branched polymer. A process for preparing the heteromorphic polymer composition of any of the preceding claims, wherein the process is characterized by comprising: (a) polymerizing ethylene and optionally one or more α-olefin comonomers under reaction conditions to form a comonomer that forms branches; and (b) polymerizing ethylene, one or more α-olefin comonomers, and the polymer forming branches of (a) under reaction conditions to form the heteromorphic polymer composition, wherein the crystallinity at ambient temperature of the branching polymer it is at least 5 percent larger than the core structure forming polymer. The process of claim 10, wherein the polymerization of (a) occurs in a first reactor and the polymerization of (b) occurs in a second reactor, or wherein the polymerization of (a) occurs in the same reactor as the polymerization of (b), and wherein the first catalyst is employed during the polymerization of (a) and a second compatible catalyst is employed during the polymerization of (b). 1

2. A process for preparing the heteromorphic polymer composition of any of the preceding claims, wherein the process is characterized by comprising: (a) polymerizing ethylene and optionally one or more α-olefin comonomers under reaction conditions to form a stream of reaction that contains a polymer that forms branches; (b) polymerizing ethylene and one or more α-olefin comonomers to form a reaction stream containing a polymer that forms linear or substantially linear homogeneous core structure, (c) optionally isolating the branching polymer from the reaction stream from (a) and the polymer forming the central structure of the reaction stream of (b), and (d) reacting the branching polymer and the polymer forming the core structure, in the presence of a radical initiator free, to attach the polymer that forms the branching of the polymer that forms the core structure to produce the heteromorphic polymer composition; wherein the branching polymer has a crystallinity at room temperature, which is at least 5 percent greater than that of the polymer forming the core structure. The process of claim 12, wherein the reaction of step (d) occurs before the isolation of the branching polymer and the polymer forming the core structure from the reaction streams of (a) and (b) , and the process further comprises: (e) isolating the heteromorphic polymer composition from the combined reaction stream. The heteromorphic composition of, or made in accordance with any of the preceding claims, in the form of an adhesive, sealant, coating, molded part, film, thermally formed part or fiber. 15. A hot melt adhesive formulation, which comprises the heteromorphic composition or is made according to any of the preceding claims. 16. The hot melt adhesive formulation of claim 15, characterized by having a probe viscosity of at least 200 grams and an upper service temperature that is at least 10 ° C higher than that of hot melt adhesive comprising a mixture unreacted from the branched polymer and the central structure polymer provided in equal amounts as is present in the heteromorphic polymer composition.