RU2196152C2 - Heteromorphous polymer compositions - Google Patents

Abstract

FIELD: polymer materials. SUBSTANCE: composition contains (i) main chain of homogenous linear or essentially linear ethylene/alpha-olefin copolymer and (ii) side chain attached to main chain, side chain containing ethylene homopolymer or ethylene/alpha-olefin copolymer, which is characterized by density by at least 0.004 g/cu.cm superior to mainchain polymer density and has degree of crystallinity higher than that of mainchain polymer. At least one of main-chain polymers and side-chain polymers can be functionalyzed to enhance adhesion to polar surfaces. EFFECT: improved higher utilization temperature limit. 6 cl, 8 dwg, 7 tbl

Description

 The invention relates to heteromorphic olefin polymers. In particular, the invention described below relates to olefin polymers containing, as the main chain, a homogeneously branched linear or substantially linear ethylene / α-olefin copolymer and a long side chain in the form of a high density ethylene homopolymer or an ethylene / α-olefin copolymer which branches off from the copolymer main chain.

 Homogeneous ethylene / α-olefin copolymers are characterized by a narrow molecular weight distribution and a narrow distribution of side short chains. In addition, homogeneous ethylene copolymers containing long side chains, known as "substantially linear" ethylene polymers, are described and claimed in U.S. 5,272,236 and in U.S. 5,278,272.

The absence of waxy components with a low molecular weight and the ability to evenly distribute the comonomer made it possible to obtain high-quality elastomers such as ethylene / propylene, ethylene / butene and ethylene / octene elastomers and the like. However, due to the fact that linear and essentially linear ethylene polymers do not have a highly linear fraction characteristic of heterogeneously branched polyethylene (and thus a high melting peak of the crystalline phase), homogeneous linear and essentially linear ethylene polymers tend to have worse resistance to the action of high temperatures, especially if the density of the polymer is less than 0.920 g / cm ³ , compared with non-uniformly branched polymers with the same density. For example, uniform linear and substantially linear elastomers may lose their strength at 60 ^{° C.} or at lower temperatures. This was attributed to the fact that such low density polymers have a molecular structure that is characterized by the presence of fringed micelles, and usually does not have lamellar structures with a higher melting point. Despite the fact that the difference will be less pronounced, homogeneous linear and essentially linear ethylene polymers with even higher densities, which have lamellar structures, generally melt at lower temperatures than their nonuniformly branched partners. Regardless of the polymerization catalyst, the polyethylene is limited in practical use above the melting point of their crystalline phase, which does not exceed approximately 140 ^o C.

By mixing grades of polyethylene with a high degree of crystallinity with elastomeric grades with a low degree of crystallinity, the temperature of use of elastomeric grades can be increased. However, more significant improvements in resistance to high temperatures are desirable. However, in addition to this, generally speaking, as the content of the fraction with a higher density increases, the resistance to high temperatures also increases, despite the fact that the modulus also increases (and thus the elastomeric properties in the case of mixtures with uniform linear or substantially linear ethylene polymers having a density lower than 0.900 g / cm ³ are undesirably reduced). In the case of mixtures with homogeneous linear and essentially linear ethylene polymers having a density exceeding 0.900 g / cm ³ , due to the fact that the content of the fraction with a higher density increases, the resistance to high temperatures also increases, while the tensile strength and impact strength undesirably reduced.

 In U. S. Patent No. 5,530,072 describes polymers characterized by long side chains (long chain branches) formed by grafting linear polyethylene onto themselves using a free radical initiator. Despite the fact that this grafting on itself contributes to an increase in the molecular weight of polyethylene and an improvement in the strength of the melt, it does not affect the crystallinity of polyethylene and thus it does not affect the resistance of polyethylene to high temperatures.

 In U. S. Patent No. 5,346,963, grafted modified substantially linear ethylene polymers are described that are optionally blended with thermoplastic polymers such as high density polyethylene, linear low density polyethylene and low density polyethylene.

 Industry would have discovered the advantages of an elastomer that would have improved performance at high temperatures without compromising modulus and / or tear and toughness. Such improved performance at high temperatures can provide an advantage, for example, for shoe soles that are better able to withstand heat in a clothes dryer. In another embodiment, such improved performance at high temperatures may provide an advantage, for example, for pressure sensitive adhesives that exhibit reduced creep resistance.

 As used herein, the term “polymer” refers to a compound resulting from the polymerization of monomers, either of the same or of a different type. The generic term "polymer" thus encompasses the term "homopolymer", commonly used to refer to polymers derived from only one type of monomer, and the term "copolymer", which is defined below. The term "copolymer" refers to polymers resulting from the polymerization of at least two different types of monomers. The generic term “copolymer” thus includes the term “copolymer”, which is commonly used to refer to polymers derived from two different monomers, as well as polymers derived from more than two different types of monomers.

The invention described below relates to a unique polymer composition comprising: (A) as a backbone a homogeneous linear or substantially linear ethylene / α-olefin copolymer; and (B) an ethylene homopolymer or an ethylene / α-olefin copolymer that attaches to the copolymer backbone and which has a density that is at least 0.004 g / cm ³ higher than the density of the backbone of the first copolymer. Such polymer compositions will resist deformation at high temperatures better than a comparable physical mixture or a mixture of the first and second copolymers obtained in the reactor. Such improved performance at high temperatures is manifested in increased values of the temperature of work under load (ULST), that is, the tendency of heteromorphic polymer compositions to lose their properties due to softening / melting, as measured using a solid state rheometer using the procedure proposed below.

 Not wishing to be bound by any theory, the applicant believes that the principle of material science, used to improve the high-temperature performance of homogeneous linear or essentially linear elastomers, is illustrated in FIG. 1. As shown in FIG. 1, the elastomer acts as a soft segment to provide flexibility at room temperature for the heteromorphic polymer composition. Grafting a hard segment, such as high density polyethylene, which has a higher melting point of the crystalline phase, improves ULST by virtue of the fact that hard segments co-crystallize in their own small material-scattered domains and serve to bind elastomeric chains into a three-dimensional network.

 Depending on the composition of the branch polymer and the method of introducing the branch, the branch may have many types, of which some exemplary types are illustrated in FIG. Figure 2-1 shows the main chain of a substantially linear copolymer with three different types of polymer branch compounds. 2-1 (a) illustrates a branch resulting from the presence of an “H-shaped compound” with a polymer of the main chain. It, for example, can be introduced as a result of random crosslinking of the polymer of the main chain and the polymer - the precursor of the heteromorphic long chain branch. FIG. 2-1 (B) illustrates a long chain branch joining a backbone polymer in two (or more) positions. Given that the long-chain branch can still crystallize or form a “hard” phase so that the temperature resistance and / or physical properties of the polymer are improved, this method of introducing the long-chain branch is acceptable and is within the scope of our definition of a long-chain branch. Figure 2-1 (C) illustrates the formation of a "T - shaped connection" with the polymer of the main chain. For example, it can be formed by grafting the reactive end group of the polymer - the precursor of the heteromorphic long chain branch to the polymer of the main chain, or can be obtained by copolymerizing a reactive end group, such as vinyl, with monomers during the polymerisation of the polymer of the main chain (in this case of course, the "backbone polymer" is simply a concept and is essentially not available in its pure form).

 FIG. 2-2 illustrate an example of a variant in which the polymer of the main chain of the linear copolymer (2-2) has heteromorphic "T" long-chain branches, such as those resulting from copolymerization or grafting of end groups.

 The ethylene / α-olefin copolymer (A), which constitutes the backbone of the heteromorphic olefin polymer of the present invention, will be either a uniform linear or substantially linear ethylene / α-olefin copolymer, each of which is described in more detail below.

The density of the polymer of the main chain depends on the type and amount of comonomer used. The density can be adjusted in accordance with methods known to those skilled in the art in order to adjust the softness of the polymer in the range from highly amorphous elastomeric grades to highly crystalline non-elastomeric grades. The choice of polymer density of the main chain will depend on the requirements of each application in accordance with the performance requirements known to those skilled in the art. However, usually the density of the polymer of the main chain will be less than 0.920 g / cm ³ , preferably less than 0.900 g / cm ³ , more preferably less than 0.880 g / cm ³ . In applications in which the best elastomeric properties are required, the density of the polymer of the main chain will be less than 0.870 g / cm ³ , preferably less than 0.865 g / cm ³ , with the possibility of reaching densities up to 0.850 g / cm ³ .

 The molecular weight of the polymer of the main chain in the same way can vary according to each system. If the branch polymer is attached to the backbone polymer by crosslinking or grafting, it may be preferable to reduce the molecular weight of the backbone copolymer to reduce gelation, especially if the branch polymer has a high molecular weight or multifunctionality in the reactive regions. An aspect of the present invention is that excellent physical properties can be obtained even for relatively low molecular weight backbone polymers due to the optimized connectivity provided by the heteromorphic nature of the compositions of the present invention. Thus, good physical properties and good processability can be obtained simultaneously.

However, typically the backbone polymer will have a melt index (I ₂ ) in the range of 0.01 to 10,000 g / 10 min, and preferably in the range of 0.01 to 1000 g / 10 min. Particularly preferred melt indices exceed 10 g / 10 min, more preferably exceed 20 g / 10 min. Note that for polymers with a low molecular weight, that is, polymers having a melt index in excess of 1000 g / 10 min, the molecular weight can be established more likely by measuring the melt viscosity of the polymer at 350 ^o F (177 ^o C). Melt viscosities at 350 ^° F (177 ^° C) for polymers having melt indices of 1000 g / 10 min and 10,000 g / 10 min when measured by the method described in the Test Procedures section below are approximately 8,200 and 600 cP (8200 and 600 MPa • s, respectively).

Branch polymer (B) that attaches to the backbone of polymer (A) may be any polymer that can be copolymerized with monomers during the preparation of the backbone polymer or which can be grafted to or crosslinked to the polymer of the backbone, and which has a density which is at least 0.004 g / cm ³ , preferably at least 0.006 g / cm ³ , more preferably at least 0.01 g / cm ³ higher than the density of the polymer of the main chain. Preferably, the branch polymer (B) in its pure state would have a glass transition temperature (T _g ) or a melting point of the crystalline phase (T _m ) that is at least 10 ^° C, preferably 20 ^° C, and most preferably at least at least 50 ^o With would exceed T _g or T _m (depending on which one is higher) of the polymer of the main chain in its pure state. Please note that for the purposes of the present invention, the term “grafting” refers to the binding of one terminal group of the branch polymer to the polymer of the main chain, while the term “crosslinking” means, in a limited interpretation, binding through one or more bonds elsewhere along the predecessor of the long chain branch (i.e., not at the end group) to form a composition with a heteromorphic long chain branch, rather than a crosslinked network.

 Non-limiting examples of the present invention, examples of heteromorphic long chain branch materials include heterogeneously and uniformly branched linear ethylene homopolymers and ethylene / α-olefin copolymers, as well as substantially linear ethylene homopolymers and ethylene / α-olefin copolymers, each of which is described in more detail below. Such branch polymers can also be further functionalized.

A suitable branch polymer for one backbone polymer may not be suitable for another backbone polymer. For example, a suitable branch polymer for a uniform linear or substantially linear ethylene / octene copolymer having a density of 0.865 g / cm ³ is an ethylene / octene copolymer having a density of 0.900 g / cm ³ . However, the same branch polymer will not be suitable for use in conjunction with the polymer backbone, which is a uniform linear or substantially linear ethylene / octene copolymer having a density of 0.920 g / cm ³ due to the fact that T _m for the first does not exceed at least 10 ^o With T _m for the latter (and in fact it is much lower).

The heteromorphic long chain branch will also have sufficient molecular weight to be able to crystallize or phase with other molecules of the branch polymer or with an additional polymer added. Preferably, the heteromorphic long chain branch would have a weight average molecular weight (M _w ) of at least 1000, preferably at least 3000 when measured in accordance with the procedure described in the Test Methods section below.

 The amount of polymer of the main chain must be sufficient to create a continuous phase or a continuous phase from it together with another continuous phase in the mixture of the polymer of the main chain and the polymer of the heteromorphic long chain branch. In particular, the weight ratio of the polymer backbone to the branch polymer will generally exceed 1: 3, preferably will exceed at least 1: 2, and most preferably will exceed 1: 1. Those skilled in the art will recognize that the optimum ratio will be vary depending on the application and the resulting preferences regarding elastomeric properties, high temperature properties, modulus / stiffness, and the like.

The average number of heteromorphic long chain branches per molecule of the polymer backbone should be sufficient to create a final polymer composition with improved high temperature resistance when measured by RSA and / or an improved tensile strength that would exceed a tensile strength that would exceed obtained as a result of simple physical mixing of comparable polymers without copolymerization, grafting or crosslinking. Preferably, the compositions of the present invention would exhibit resistance to temperature when measured by RSA, at least 10 ^o With, preferably at least 15 ^o With higher than the corresponding characteristic for a physical mixture of comparable polymers. It is preferred that the compositions of the present invention exhibit a tensile strength that is at least 70% of the corresponding characteristic for a physical mixture of comparable polymers, more preferably at least 85%, most preferred, which would balance the corresponding characteristic of a physical mixture of comparable polymers or would exceed it, it would be easy to obtain a tensile strength, which would be equal to 120% of the corresponding characteristic for physical mixtures of comparable polymers.

The average number of heteromorphic long chain branches per molecule of the polymer backbone, however, should not be so large as to reduce the elastomeric properties of the polymer backbone to an unacceptable level. For example, if the polymer of the main chain has a density of less than 0.900 g / cm ³ , the composition of the present invention will preferably exhibit a percentage elongation that will be at least 40%, more preferably that will be at least 50% , even more preferably, which will be equal to at least 60% of the corresponding characteristic for a mixture of comparable polymers, so that it would be easy to obtain compositions exhibiting relative elongations expressed in p percentages that would be equal to or greater than the corresponding characteristic for a comparable mixture.

Ethylene polymers useful as the backbone of polymer (A) and heteromorphic long chain branch (B) can be independently copolymers of ethylene and at least one α-olefin. Suitable α-olefins are represented by the following formula:
CH ₂ = CHR,
where R is a hydrocarbon radical. The comonomers that form part of the polymer of the main chain (A) may be the same or different as the comonomers that form a heteromorphic long chain branch (B).

R generally has from one to twenty carbon atoms. Suitable α-olefins for use as comonomers in a solution, gas phase or suspension polymerization process or a combination thereof include C ₃ -C ₂₀ α-olefins, styrene, tetrafluoroethylene, vinylbenzocyclobutane, 1,4-hexadiene, 1,7-octadiene and cycloalkenes, for example cyclopentene, cyclohexene, cyclooctene, norbornene (NB) and ethylidene norbornene (ENB). Preferred C ₃ -C ₂₀ α-olefins include 1-propylene, 1-butene, 1-isobutylene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene and 1-octene, as well as other such types of monomers. Preferably, the α-olefin would be 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, NB or ENB, or mixtures thereof. More preferably, the α-olefin would be 1-hexene, 1-heptene, 1-octene, or mixtures thereof. Most preferably, the α-olefin would be 1-octene.

Ethylene / α-olefin / diene terpolymers can also be used as elastomeric polymers in the present invention. Suitable α-olefins include the α-olefins described above as suitable for the preparation of ethylene / α-olefin copolymers. Dienes suitable as monomers for the preparation of such 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 make terpolymer include:
a) straight chain acyclic dienes such as 1,4-hexadiene, 1,5-heptadiene and 1,6-octadiene;
b) branched 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 cycle alicyclic dienes such as 4-vinylcyclohexene, 1-allyl-4-isopropylidenecyclohexane, 3-allylcyclopentene, 4-allylcyclohexene and 1-isopropenyl-4-butenylcyclohexane;
d) alicyclic dienes with several fused or bridged rings, such as dicyclopentadiene; alkenyl, alkylidene, cycloalkenyl and cycloalkylidene-norbornenes such as 5-methylene-2-norbornene, 5-methylene-6-methyl-2-norbornene, 5-methylene-6, 6-dimethyl-2-norbornene, 5-propenyl -2-norbornene, 5- (3-cyclopentenyl) -2-norbornene, 5-ethylidene-2-norbornene, 5-cyclohexylidene-2-norbornene and the like.

 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 and the like. A suitable conjugated diene is piperylene.

 Preferred terpolymers for the practice of the present invention are terpolymers of ethylene, propylene and non-conjugated diene (EPDM). Such terpolymers are commercially available.

 Homogeneous (homogeneous) polyethylenes, which can be used as components (A) and (B) of the present invention, are distributed between two broad categorical groups, linear homogeneous polyethylene and essentially linear homogeneous polyethylene. Both of them are known.

“Homogeneous” polymers are ethylene copolymers in which any comonomer is randomly distributed within a molecule of a given copolymer, and substantially all of the copolymer molecules have the same ethylene / comonomer ratio within that copolymer. Homogeneous polymers are generally characterized in that they have a single melting peak in the range between -30 and 150 ^{° C.} as determined by differential scanning calorimetry (DSC). A single melting peak is determined using a differential scanning calorimeter standardized with indium and deionized water. The method uses sample amounts of 3-7 mg, “first warming up” to approximately 180 ^{° C.} , maintaining this temperature for 4 minutes, cooling at 10 ^° C./min to –30 ^{° C.} , maintaining this temperature for 3 minutes and heating at 10 ^o C / min to 140 ^o C in the "second heating". A single melting peak is obtained from the temperature dependence of the heat flux for the “second heating”. The total heat of fusion of the polymer is calculated from the area under the curve.

For polymers having a density in the range from 0.875 to 0.910 g / cm ³ , a single melting peak can be detected depending on the sensitivity of the equipment “shoulder” or “hump” on the peak side corresponding to melting at lower temperatures, which is less than 12%, typically less than 9%, and even more often less than 6% of the total heat of fusion of the polymer. Such an artifact can also be observed for homogeneous linear polymers, such as Exac ^™ polymers (which can be purchased from the Exxon Chemical Company), and can be detected based on a monotonous change in the angle of inclination of a single melting peak in the artifact melting region. Such an artifact occurs in the range of 34 ^{° C.} , usually in the range of 27 ^{° C.} , and even more often in the range of 20 ^{° C. of} the melting temperature of a single melting peak. The heat of fusion attributable to the artifact can be separately determined by integrating the area related to it only under the curve on the dependence of the heat flux on temperature.

 In addition to this or as an alternative to this, polymer homogeneity is usually described by CDBI (branch distribution index in the composition), and it is defined as the weight percent of polymer molecules having a comonomer content within 50% of the average total molar content of the comonomer. The CDBI of a polymer is easily calculated from data obtained using techniques known in the art, such as, for example, fractionation by elution with increasing temperature (abbreviated as “TREF” in this document), as described, for example, in Wild et al., Journal of Polymer Science, Poly. Phys. Ed., Vol. 20, p. 441 (1982), U. S. Patent 4,798,081 (Hazlitt et al.) Or U.S. Patent 5,089,321 (Chum et al.). CDBI for homogeneous linear and for substantially linear ethylene / α-olefin polymers used in the present invention preferably exceeds 50%, more preferably exceeds 70%.

Homogeneous polymers usually also have a molecular weight distribution, M _w / M _n , of less than or equal to 3 (if the density of the copolymer is less than about 0.960 g / cm ³ ), preferably less than or equal to 2.5. Molecular mass determination is performed using polystyrene standards with a narrow molecular weight distribution (from Polymer Laboratories) in combination with their elution volumes. Essentially linear ethylene polymers are analyzed by gel permeation chromatography (GPC) using a Waters 150 C high temperature chromatographic system equipped with a differential refractometer and three columns with mixed porosity. Columns are supplied from Polymer Laboratories and they are usually packed with material with pore sizes of 10 ³ , 10 ⁴ , 10 ⁵ and 10 ⁶ . The solvent is 1, 2, 4-trichlorobenzene, from which sample solutions with a concentration of 0.3 weight are prepared for introduction into the column. % The flow rate is 1.0 ml / min, the operating temperature of the system is 140 ^o C, and the size of the injected sample is 100 μl.

Equivalent molecular weights of polyethylene are determined using appropriate Mark Houwink coefficients for polyethylene and polystyrene (as described by Williams and Ward in Journal of Polymer Science, Polymer Letters, vol. 6, p. 621, 1968) to obtain the equation Mpolyethylene = a • (Mpolystyrene) ^b . In this equation, a = 0.4316, and b = 1.0. The weight average molecular weight M _{w is} calculated in the usual way in accordance with the formula
M _w = Σ (w _i • M _i ),
where Wi and Mi represent the weight fractions and molecular weight, respectively, for the i-th fraction eluted from the GPC column.

Homogeneous linear ethylene polymers have long been commercially available. As indicated by way of example in US Patent No. 3,645,992 by Elston, homogeneous linear ethylene polymers can be prepared in commonly used polymerization processes using Ziegler-type catalysts, such as, for example, zirconium and vanadium catalyst systems. US Patent No. 4,937,299 authors Ewen ef al. and US Patent No. 5,218,071 to Tsutsui et al. describe the use of metallocene catalysts, such as catalyst systems based on zirconium and hafnium, to produce homogeneous linear ethylene polymers. Homogeneous linear ethylene polymers are typically characterized in that they have a molecular weight distribution of M _w / M _{n of} approximately 2. Commercially available examples of homogeneous linear ethylene polymers include those sold by Mitsui Petrochemical Industries as Tafmer brand polymers ^TM "and the company" Exxon Chemical Company "as the polymer brand" Exact ^TM ".

Essentially linear ethylene polymers (SLEPs) are homogeneous polymers having long chain branches. They are described in US Patent Nos. 5,272,236 and 5,278,272. SLEPs are obtained from the Insite ^TM catalyst process and technology and can be purchased from The Dow Chemical Company as Affinity ^TM polyolefin plastomers (POPs) and DuPont Dow Elastomers, LLC as polyolefin elastomers (ROE) of the Engage ^TM brand. SLEPs can be prepared by solution, suspension, or gas phase, preferably in the solution phase, polymerization of ethylene and one or more possible α-olefin comonomers in the presence of a geometry limited catalyst, such as described in European Patent Application 416.815-A.

 The term “substantially linear” means that in addition to the short-chain branches attributed to the homogeneous introduction of the comonomer, the ethylene polymer is also characterized by the presence of long-chain branches, such that the polymer main chain has, on average, from 0.01 to 3 long-chain branches / 1000 carbon atoms. Preferred substantially linear polymers for use in the present invention have as substituents from 0.01 long chain branches / 1000 carbon atoms to 1 long chain branch / 1000 carbon atoms, and more preferably from 0.05 long chain branches / 1000 carbon atoms to 1 long chain branch / 1000 carbon atoms.

“Long chain branch” (LCB) means a chain length of at least 6 carbon atoms, a length exceeding a given number of atoms cannot be determined by ¹³ C nuclear magnetic resonance spectroscopy. Each long chain branch has the same comonomer distribution as the polymer backbone, and it can be the same length as the polymer backbone to which it is attached.

The presence of a long chain branch can be determined for ethylene polymers via ¹³ C nuclear magnetic resonance spectroscopy (NMR) and can be expressed in quantitative terms using the method described by Randall (Rev. Macromol. Chem. Phys., P. 29, v. 2 & 3, p. 285-297).

Practically available at present, ¹³ C nuclear magnetic resonance spectroscopy cannot determine the length of a long chain branch exceeding six carbon atoms. However, there are other known methods suitable for determining the presence of long chain branches in ethylene polymers, including ethylene / 1-octene copolymers. Two of these methods are gel permeation chromatography in combination with a small angle laser light scattering detector (GPC - LALLS) and gel permeation chromatography in combination with a differential viscometer detector (GPC - DV). The use of these techniques for the detection of long chain branches and the substantiating data of the theory techniques have been well documented in the literature. See, for example, Zimm, GH and Stockmayer, WH, J. Chem. Phys., 17, 1301 (1949) and Rudin, A., Modern Methods of Polymer Characterization, John Wiley & Sons, New York (1991), pp. 103 - 112, both of these works are given as references.

A. Willem deGroot and R. Steve Chum, both of The Dow Chemical Company, at a conference of the Federation of Analytical Chemistry and Spectroscopy Society (FACSS) on October 4, 1994 in St. Louis , Missouri, presented data demonstrating that the GPC - DV is a useful technique for quantifying the presence of long chain branches in SLEPs. In particular, deGroot and Chum found that the level of long chain branches in homogeneous SLEP samples when measured using the Zimm - Stockmayer equation correlated well with the level of long chain branches when measured using ¹³ C NMR.

 In addition, deGroot and Chum found that the presence of octene does not change the hydrodynamic volume of the polyethylene samples in the solution, and the increase in molecular weight attributed to short-chain octene branches as such if there is information about the molar percent of octene in the sample can be explained. By decomposing the contribution to the molecular weight increase attributed to short-chain 1-octene branches, deGroot and Chum have shown that GPC-DV can be used to quantify the content of long-chain branches in substantially linear ethylene / octene copolymers.

DeGroot and Chum also showed that the Log diagram (I ₂ , melt index) versus Log (weight-average molecular weight by GPC) when determined by GPC - DV illustrates that the appearance of long chain branches (but not the magnitude of long branches) for SLEP comparable to the corresponding characteristic for high-branched high-pressure and low-density polyethylene (LDPE), and they clearly differ from ethylene polymers obtained using Ziegler type catalysts, such as titanium complexes, and conventional orov to obtain homogeneous polymers, such as hafnium and vanadium complexes.

For ethylene / α-olefin copolymers, the long chain branch is longer than the short chain branch, which is obtained by introducing the α-olefin (α-olefins) into the polymer backbone. The empirical effect of the presence of a long chain branch in the substantially linear ethylene / α-olefin copolymers used in the present invention manifests itself in improved rheological properties, which are quantified and expressed herein in terms of gas extrusion rheometry (GER) results and / or increases the degree of flow of the melt I ₁₀ / I ₂ .

 In contrast to the term “substantially linear,” the term “linear” means that the polymer has no measurable or demonstrable long chain branches, that is, the polymer has substituents on average less than 0.01 long chain branches / 1000 carbon atoms.

SLEP are also characterized by the fact that they have:
(a) melt flow coefficient, I ₁₀ / I ₂ ≥5.63,
(b) the molecular weight distribution of M _w / M _n , established by gel permeation chromatography and determined by the equation:
(M _w / M _n ) ((I ₁₀ / I ₂ ) -4.63,
(c) gas extrusion rheology such that the critical shear rate at the start of surface fracture of the extrusion flow for SLEP would be at least 50 percent greater than the critical shear rate at the start of surface fracture of the extrusion flow for linear ethylene polymer, where SLEP and the linear ethylene polymer comprise the same comonomer or comonomers, the linear ethylene polymer has an I _2, M _w / M _n and density within 10% of the corresponding values for the SLEP, and where appropriate the critical RP G shear rate for SLEP and the linear ethylene polymer are measured at the same melt temperature using a gas extrusion rheometer, and
(d) a single melting peak, determined by the method of differential scanning calorimetry, DSC, in the interval between - 30 and 150 ^o C.

The determination of the critical shear rate and critical shear stress in relation to the destruction of the extrusion flow, as well as other rheological properties, such as the rheological processing index (RT), are made using a gas extrusion plastometer (GER). A gas extrusion plastometer is described by M. Shida, RN Shroff, and LV Cancio in Polymer Engineering Science, vol. 17, No. 11, page 770 (1977) and Rheometers for Molten Plastics by John Dealy, published by Van Nostrand Reinhold Co. (1982) on pages 97 to 99. GER experiments are performed at a temperature of 190 ^{° C.} , at nitrogen pressures in the range between 250 and 5500 psig (1.7 to 38 MPa), using a head with a diameter of 0.0754 mm and with a ratio of length to diameter of 20: 1 with an average input angle of 180 ^o . For the substantially linear ethylene polymers described herein, PI is the apparent viscosity (in kilo poises) for the material, measured by GER at an apparent shear stress of 2.15 x 10 ^o dyn / cm ² (0.215 MPa). Essentially linear ethylene polymers for use in the present invention include ethylene copolymers and have a PI in the range of 0.01 to 50 kP (0.01 to 50 kg / cm · s) (1 to 5000 Pa · s), preferably 15 kP (15 kg / cm • s) (1500 Pa • s) or less. The substantially linear ethylene polymers used herein have a PI of less than or equal to 70% of the PI of a linear ethylene polymer (either a Ziegler polymerized polymer or a linear, uniformly branched polymer described by Elston in US Patent 3,645,992) having I ₂ , M _w / M _n and density, each of these indicators within 10% of the corresponding values for essentially linear ethylene polymers.

The rheological behavior of substantially linear ethylene polymers can also be characterized by the Dow Rheology Index (DRI), which expresses “normalized relaxation time as the result of the presence of long chain branches”. (See S. Lai and GW Knight ANTEC '93 Proceedings, INSITE ^TM Technology Polyolefins (SLEP) - New Rules in the Structure / Rheology Relationship of Ethylene α - Olefin Copolymers, New Orleans, La., May 1993). DRI values range from 0 for polymers that do not have any measurable long chain branches (such as Tafmer ^TM purchased from Mitsui Petrochemical Industries and Exact ^TM purchased from Exxon Chemical Company ") to about 15, and they are independent of the melt index. In general, for ethylene polymers produced at low to medium pressures (especially at lower densities), DRI provides improved correlations with melt elasticity and fluidity at high shear compared to trying to make the same correlations using flow coefficients melt. For substantially linear ethylene polymers useful for the present invention, the DRI is preferably at least 0.1 and in particular at least 0.5, and in particular even more preferably at least 0.8. DRI can be calculated using the equation:
DRI = (3652879 • τ $\genfrac{}{}{0ex}{}{\text{1,00649}}{\text{0}}$ / η ₀ -1) / 10,
where τ ₀ represents the characteristic relaxation time of the material, and η ₀ represents the viscosity of the material at zero shear. Both τ ₀ ,, and η ₀ are the values obtained by approximation with the “best fit” to the following Cross equation:
η / η ₀ = 1 / (1+ (γ • τ ₀ ) ^1-n ),
where n is an exponent for a material, and η and γ are measured viscosity and shear rate, respectively.

The basic definitions of viscosity and shear data were obtained using a rheometric mechanical spectrometer (RMS - 800) in the dynamic transmission mode from 0.1 to 100 rad / s at 160 ^o C and a gas extrusion plastometer (GER) at extrusion pressures in the range from 1000 up to 5000 psi (from 6.89 to 34.5 MPa), which corresponds to a shear stress in the range from 0.086 to 0.43 MPa, using a head with a diameter of 0.0754 mm and a ratio of length to diameter of 20: 1 at 190 ^o C. Definitions for a particular material can be held in the range of from 140 to 190 ^o C. the need for adjustment to variations in melt index.

 The dependence of the apparent shear stress on the apparent shear rate is used to identify the phenomena of destruction of the extrusion flow and to obtain quantitative data regarding the critical shear rate and critical shear stress for ethylene polymers. According to Ramamurthy in Journal of Rheology, 30 (2), 337 - 357, 1986, above a certain critical flow rate, the observed extrudate irregularities in a broad sense can be classified with two main types: surface extrusion fracture and general extrusion fracture.

Superficial destruction of the extrusion flow takes place under seemingly stationary flow conditions and, with respect to specific characteristics, it ranges from loss of specular gloss by the melt to more serious types of “shark skin”. In this document, when determined using the above-described GER, the onset of surface extrusion flow destruction (OSMF) is characterized by the onset of extrudate loss of gloss, in which the surface roughness of the extrudate can only be detected by magnification of 40 times. The critical shear rate at the start of surface fracture of the extrusion flow for substantially linear ethylene polymers is at least 50% higher than the critical shear rate at the start of surface fracture of the extrusion stream for linear ethylene polymer having substantially the same I ₂ and M _w / M _n .

General destruction of the extrusion flow takes place under unsteady flow conditions during extrusion and, with regard to specific characteristics, it ranges from uniform (for example, alternating uneven and smooth or spiral) to random distortions. For commercial acceptability, in order to maximize the performance of films, coatings and castings, surface defects should be minimal, if not absent. The critical shear stress at the time of the beginning of the total destruction of the extrusion flow for essentially linear ethylene polymers, in particular for those having a density exceeding 0.910 g / cm ³ used in the present invention, exceeds 4 • 10 ⁶ dyne / cm ² (0, 4 MPa).

Essentially linear ethylene polymers are known for having excellent processability, despite having a relatively narrow molecular weight distribution (i.e., the ratio M _w / M _{n is} usually less than 2.5). Moreover, in contrast to uniformly and heterogeneously branched linear ethylene polymers, the melt flow coefficient (I ₁₀ / I ₂ ) for substantially linear ethylene polymers can vary regardless of the molecular weight distribution of M _w / M _n . Accordingly, the backbone of the polymer (A) of the heteromorphic polymer compositions of the present invention is preferably a substantially linear ethylene polymer.

Inhomogeneous polyethylenes that can be used as heteromorphic long chain branches (B) in the practice of the present invention are classified according to two broad categorical groups, those obtained using a free radical initiator at high temperature and high pressure, and those obtained at using a coordination catalyst at high temperature and relatively low pressure. The former are generally known as low density polyethylene (LDPE) and they are characterized by the presence of branch chains of polymerized monomeric units hanging from the polymer backbone. LDPE polymers generally have a density in the range of 0.910 to 0.935 g / cm ³ . Ethylene polymers and copolymers resulting from the use of a coordination catalyst, such as a Ziegler or Philips catalyst, are generally known as linear polymers due to the essentially absence of branch chains of the polymerized monomer units hanging from the main chain. High density polyethylene (HDPE), generally having a density in the range of from about 0.941 to about 0.965 g / cm ³ , is usually a homopolymer of ethylene or a copolymer of ethylene and small amounts of monomer and it contains relatively
a small number of branch chains compared to various linear copolymers of ethylene and α-olefin. HDPE is well known, commercially available in various grades, and it can be used in the present invention.

Linear copolymers of ethylene and at least one α-olefin with a carbon number of 3 to 12, preferably a carbon number of 4 to 8, are also well known and commercially available. As is well known in the relevant field, the density of a linear ethylene / α-olefin copolymer is a function of both the length of the α-olefin and the content of such a monomer in the copolymer relative to the amount of ethylene, the greater the length of the α-olefin and the greater the available content α-olefin, the lower will be the density of the copolymer. The densities of such linear polymers are generally in the range of 0.87 to 0.91 g / cm ³ .

Both the materials obtained using free-adic catalysts and those obtained using coordination catalysts are well known in the relevant field, as are the methods for their preparation. Inhomogeneous linear ethylene polymers can be purchased from The Dow Chemical Company under the brand name of Dowlex ^TM LLDPE and Attane ^TM ULDPE polymers. Inhomogeneous linear ethylene polymers can be prepared by solution, suspension, or gas phase polymerization of ethylene and one or more possible α-olefin comonomers in the presence of a Ziegler-Natta catalyst during processes such as those described in US Patent No. 4,076,698 by Anderson et al. Inhomogeneous ethylene polymers are typically characterized in that they have molecular weight distributions of M _w / M _n in the range of 3.5 to 4.1. Relevant discussions regarding both of these classes of materials and methods for their preparation are found in US Patent No. 4,950,541 and in the patents to which he refers.

Inhomogeneous polymers are ethylene / α-olefin copolymers, which are characterized by the presence of a linear main chain and a melting curve obtained by differential scanning calorimetry (DSC), having a distinguishable melting peak above 115 ^o C, attributed to the high density fraction. Inhomogeneous copolymers will usually have M _w / M _n greater than 3 (if the density of the copolymer is less than 0.960 g / cm ³ ), and they will usually have a CDBI of less than or equal to 50, which indicates that such copolymers are a mixture of molecules having varying comonomer content and varying amounts of short chain branches.

 The degree of crystallinity with respect to the ethylene polymer is a well-known property of ethylene polymers. Various techniques have been developed to measure the crystallinity of the ethylene polymer.

If the ethylene polymer is obtained solely from hydrocarbon monomers (i.e., if the ethylene polymer is a non-functionalized ethylene / α-olefin copolymer), the degree of crystallinity can be determined based on the density of the polymer using the following equation:
percentage C = (ρ-ρa) / ρ (ρc-ρa) × 100,
in which percent C is the crystallinity of the ethylene polymer, expressed as a percentage, ρa is the density of the ethylene polymer, which has a crystallinity, expressed as a percentage, of 0 (i.e. which is 100% amorphous) at room temperature (0.852 g / cm ^3), ρs is the density of an ethylene polymer at 100% degree of crystallinity at room temperature (1.000 g / cm ³⁾ and ρ represents the density of the polymer, which is carried out for determining the degree crista personality, expressed as a percentage. Density can be determined in accordance with ASTM D792, whereby samples are held at room temperature for 24 hours before being measured.

The term "temperature under load" (ULST), also called "softening temperature under load" or "SPUL", refers to the temperature at which the penetration depth of the probe into the polymer is equal to 1 mm, while using a device capable of applying a constant force equal to 1 N to the probe with a flat top having a diameter equal to 1 mm, during the procedure, the polymer temperature is increased from 25 ^o With a speed equal to 5 ^o C / min, in a nitrogen atmosphere. One such device is a thermomechanical analyzer (TMA), such as Model TMA-7, manufactured by Perkin-Elmer Instrument Company. The procedure for conducting this test is described in more detail later in the "Examples" section.

The polymer (B), forming branches and having a higher density, can be characterized by a wide range of molecular weights. On the low molecular weight side, the branch polymer will have M _n at least 2000, preferably at least 3000. On the high molecular weight side, the branch polymer will have I ₂ at least 0.05 g / cm ³ . Typical melt indices for the branch polymer are in the range of 0.05 to 40 g / 10 min.

If it is desirable to use a branch polymer with a higher molecular weight, i.e. a branch polymer having an I ₂ less than 5 g / 10 min, then a reduced number of branch polymer chains will require a higher concentration of branch polymer, i.e., an amount greater than 20 weight. % (or the use of more significant quantities of free radical initiator, that is, amounts in excess of 0.5 weight percent), in order to achieve a given increase in operating temperature under load. In contrast, if a branch polymer with a lower molecular weight is used, the presence of an increased number of shorter chains (which preferably terminate with a vinyl group) will increase the operating temperature under load, despite the use of relatively small amounts of branch polymer, i.e., amounts up to 5 wt.%.

 Not wishing to be bound by any theory, the applicant believes that in the case of lower molecular weight branch polymers, low concentrations of such a polymer can be used because heteromorphic polymer compositions will tend to have more than one small branch chain attached to each polymer backbone. As shown in figure 1, it is believed that the presence of more than one branch per molecule of the main chain will lead to a tendency to bond molecules of the polymer main chains together, which will ensure the structural integrity of the system, despite the melting of the material of the polymer main chain with a lower degree of crystallinity, at higher temperatures of use.

 Specialists in the relevant field of polymer science can imagine many ways to obtain heteromorphic compositions of the present invention.

 In one embodiment, the polymer branches with a higher degree of crystallinity and the polymer of the main chain with a lower degree of crystallinity will be obtained by the reaction of previously obtained and isolated polymer reagents. In this case, the branch polymer with a higher degree of crystallinity will react to form a T-shaped compound (as a result of grafting) or an H-shaped compound (as a result of light crosslinking) with the polymer of the main chain with a lower degree of crystallinity. This reaction can be carried out using methods known to those skilled in the art.

 In one embodiment, a hydrogen atom will be cleaved from the polymer backbone, which will react with the branch polymer. Methods for cleaving a hydrogen atom from a polymer backbone include, but are not limited to, reacting with free radicals that are generated by homolytic cleavage of molecules (e.g., compounds containing peroxide or compounds containing an azo group) or by radiation.

 The presence of an olefinic type unsaturation on the backbone polymer or branch polymer may help with the location of the grafting / crosslinking sites. For example, decomposition of the peroxide in the presence of a larger fraction of a saturated polymer of the main chain and a smaller fraction of the polymer of the branch with vinyl terminal groups will tend to inoculate the polymer of the branch on the polymer of the main chain, while the polymer of the branch without vinyl groups will undergo a cleavage reaction a hydrogen atom to form a radical that will react with the radical of the polymer of the main chain to form H-shaped compounds. Vinyl terminated branch polymers are obtained by adjusting the conditions in the reactor so that the growth of the polymerized chains is terminated as a result of the removal of beta hydride, and not as a result of a reaction with a hydrogen atom. In addition to this, additional auxiliary substances, such as molecules with mono-, di-, or triallyl functionality (for example, triallyl cyanurate), can be used to further control free-radical processes. In general, grafting is preferred to easy crosslinking due to the fact that, without gelation, more heteromorphic long chain branches can be introduced.

 The use of α, Ω dienes as a comonomer in the formation of a polymer forming more significant branches, or a polymer forming a main chain, will increase the reactivity of the polymer component. Suitable α, Ω dienes include 1, 7-octadiene and 1, 9-decadiene. When introduced, such dienes will usually be present in an amount of less than 2 per polymer chain.

 Crosslinking or grafting reactions can be carried out in a solution of two polymers in a suitable solvent or in a mixture of polymer components in a melt. The latter method is preferred. Melt mixing can be carried out in a batch mixer, such as a Banbury mixer, a roller mill, or in a continuous mixer, such as a Farrell continuous mixer, or a single screw or twin screw extruder. You can also form a mixture of polymers, and then irradiate or impregnate with a reactive solution (such as a peroxide solution) and heat. However, melt or solution mixing is preferred over these approaches.

In an alternative embodiment, the compositions of the present invention can be obtained by copolymerizing a branch polymer with monomers that form a backbone polymer. Using a dual catalyst system, one can imagine that the backbone polymer and the composition described herein (i.e., a heteromorphic polymer composition) can be copolymerized simultaneously. The method has the advantage of minimizing the gradual reduction of a polymer with high T _g / T _m in a relatively cold reactor.

 In an alternative embodiment, the compositions of the present invention can be obtained in a unit with two reactors in series, whereby the branch polymer is obtained in the first reactor and then fed to the second reactor, where it is copolymerized with monomers that form the polymer of the main chain to obtain a composition, described in this document. The second reactor should be maintained at a temperature that would exceed the temperature at which the polymer branches with a higher degree of crystallinity would form a phase separate from the polymer of the main chain, with a lower degree of crystallinity. Preferably, the copolymerization reactor would be a reactor with a high concentration of polymer ("solid phase"), such as a loop reactor, in order to achieve a maximum content of polymerizable polymer branches with a higher degree of crystallinity.

 In one embodiment, a single-center catalyst for copolymerizing higher crystallinity branch polymers with ethylene and octene can be used to produce ethylene / octene elastomers having branches in the form of HDPE side chains.

 Single center catalysts, especially geometry limited catalysts, are advantageous in that they have greater acceptability for high molecular weight monomers compared to conventional Ziegler catalysts or single center catalysts without geometry restrictions. In contrast to crosslinking, copolymerization avoids gelation even at relatively high contents of heteromorphic long chain branches due to the fact that only one section on the long chain branch will be reactive.

Preferably, the precursor monomer in the form of a heteromorphic long chain branch with high T _m or T _g would have a relatively low molecular weight and at least one olefin end group per chain to facilitate copolymerization and dissolution of the monomer in the process solvent and / or diffusion to catalytic site.

 Optionally, but can be used as comonomer in one or both polymers diene or polyene in order to modify the rate of introduction / connection during copolymerization. For example, an ethylene-diene or propylene-diene copolymer can be obtained in one reactor, then sent to a second reactor, where it is copolymerized with ethylene and octene or ethylene and propylene. Provided that the diene content is relatively low, gelation can be avoided by increasing the copolymerization rate of the polymer, the precursor of the heteromorphic branch and the main chain polymer monomers.

 Preferably, if a diene or polyene is used as a comonomer, its content will be less than 20 wt.%, More preferably less than 10 wt.% Of the composition of the present invention.

In an alternative embodiment, the heteromorphic polymer composition may be mixed with one or more additional polymers that have a structure similar to that of the branch polymer, or that can form a phase characterized by a high T _m or T _g resulting from the formation of a solid solution or co-crystallization. One example of such a blended composition is high density polyethylene. If the concentration of the branch polymer is low in the heteromorphic polymer composition, it may be necessary to provide an additional polymer for co-crystallization or solidification in the phase with branches in order to achieve the desired physical and / or temperature resistance properties. Excess polymer with a higher degree of crystallinity will advantageously crystallize with branches of heteromorphic polymer compositions with a higher degree of crystallinity, thereby increasing the thickness of the lamella, which will lead to a tendency to increase the melting temperature of the crystalline phase of the polymer composition. In addition, such an excess of a polymer with a higher degree of crystallinity will facilitate the bridge linking of two separate branches with a higher degree of crystallinity, which will increase the overall degree of crystallinity for a heteromorphic polymer composition, which will increase the operating temperature under load. A preferred method for introducing additional polymer is to simply add excess polymer branches to the melt reactor or mixer so that as the copolymerization or grafting or crosslinking takes place, the excess unreacted polymer branches will remain unreacted and be able to participate in co-crystallization or the formation of a phase with heteromorphic long chain branches.

 In yet another embodiment, the compositions of the present invention can be used in mixtures with other polymers. For example, the compositions of the present invention can be mixed with other polyolefins, such as non-uniformly branched linear ethylene / α-olefin copolymers, uniformly branched linear ethylene / α-olefin copolymers, substantially linear ethylene / α-olefin copolymers, ethylene / vinyl acetate copolymers, styrene block copolymers and amorphous polyolefins (such as polypropylene and polybutene).

 In one preferred embodiment, the heteromorphic polymer composition will include at least one component that contains polar groups. That is, either the backbone polymer or the branch polymer will preferably be functionalized by grafting a polar group thereto.

 Any unsaturated organic compound containing at least one ethylenically unsaturated site (e.g., at least one double bond), at least one carboxyl group (-COOH), and which will be grafted onto the ethylene polymer as described above can be used in the practice of the present invention. As used herein, a “carboxyl group” includes carboxyl groups as such and derivatives of carboxyl groups such as anhydrides, esters and salts (both with metals and non-metals). Preferably, the organic compound would contain an ethylene-type unsaturation site conjugated to a carboxyl group. Representative compounds include maleic, acrylic, methacrylic, itaconic, crotonic, α-methylcrotonic and cinnamic acid and their derivatives - anhydrides, esters and salts - and fumaric acid and its derivatives - ester and salt. Maleic anhydride is a preferred unsaturated organic compound containing at least one ethylene type unsaturation and at least one carboxy group.

 The content of unsaturated organic compound in the grafted backbone polymer or in the branch polymer is preferably at least 0.01 wt.%, And more preferably at least 0.05 wt.%, Based on the combined weight of the polymer and the organic compound. The maximum content of unsaturated organic compounds may vary for convenience, but usually it does not exceed 10 wt.%, Preferably it does not exceed 5 wt. %, and more preferably it does not exceed 2 wt.% of the grafted polymer.

The unsaturated organic compound can be grafted onto the desired polymer or to the branch polymer using any known technique, such as those described in USP 3,236,917 and USP 5,194,509. For example, in the '917 patent, the polymer is introduced into a twin roll mixer and mixed at a temperature of 60 ^° C. The unsaturated organic compound is then added together with a free radical initiator, such as, for example, benzoyl peroxide, and the components are mixed at 30 ^{° C.} until until vaccination is complete. In the '509 patent, the procedure is similar, except that the reaction temperature is higher, for example, from 210 to 300 ^° C, and the free radical initiator is not used or is used at a reduced concentration.

 An alternative and preferred grafting method is described in USP 4,950,541, where a twin screw extruder is used as a mixing apparatus. The ethylene polymer and the unsaturated organic compound are mixed and react with each other in an extruder at temperatures at which the reactants are in a molten state and in the presence of a free radical initiator.

 Preferably, the unsaturated organic compound is introduced into the extruder into an area in which excess pressure is maintained.

 Grafting onto substantially linear ethylene polymers, for example maleic anhydride, is described in U.S. 5,346,963, which is incorporated herein by reference.

 Upon receipt of heteromorphic polymer compositions, it should be recognized that the presence of a free radical initiator may result in limited crosslinking of the polymers of adjacent main chains, either directly from one chain to another, or via an attached branch. Provided that the level of content of such crosslinks will be insufficient for the formation of a polymer composition that cannot be processed in the fabrication or extrusion of thermoplastics, this case is also within the scope of the present invention. Preferably, the heteromorphic polymer compositions have less than 30% gel, more preferably less than 10% gel, even more preferably less than 5% gel, and most preferably less than 2% gel. Most preferably, the heteromorphic polymer compositions would essentially not contain a gel at all.

 The heteromorphic polymers of the present invention may, although not necessarily, include antioxidants, fillers, filling oils, UV stabilizers, anti-friction additives, anti-sticking agents, pigments, dyes, or blowing agents, in accordance with the practice of those skilled in the art of polymer production compositions. When used, antioxidants are usually present in an amount of less than 0.5 wt.%, Preferably less than 0.2 wt.%, Based on the total weight of the composition.

 The compositions of the present invention can advantageously be used in hot melt adhesive and pressure sensitive adhesives. In this regard, the compositions of the present invention can be mixed with suitable amounts of one or more tackifiers, one or more waxes and / or one or more plasticizers.

As used herein, the term “tackifier” refers to any of several hydrocarbon-based compositions useful in tacking a hot-melt adhesive composition. For example, several classes of tackifiers include aliphatic C ₅ hydrocarbon polymers, polystyrene polymers, hydrogenated polymers, mixed aliphatic-aromatic polymers, esterified rosins, and hydrogenated esterified rosins. The tackifiers used will typically have a viscosity at 350 ^° F (177 ^° C) when measured using a Brookfield viscometer of not more than 300 cP (300 g / cm • s) (300 mPa • s), preferably not more than 150 cPm (150 g / cm • s) (150 mPa • s), and most preferably not more than 50 cP (50 g / cm • s) (50 mPa • s). The tackifier used will typically have a glass transition temperature in excess of 50 ^° C.

Exemplary aliphatic polymers include those sold under the trade names "Escorez ^TM ", "Piccotac ^TM ", "Mercures ^TM ", "Wingtack ^TM ", "Hi-Rez ^TM ", "Quintone ^TM ", "Tackirol ^TM " and the like. Exemplary polyterpene polymers include polymers sold under the trade names "Nirez ^TM ", "Piccolyte ^TM ", "Wingtack ^TM ", "Zonarez ^TM " and the like. Exemplary hydrogenated polymers include polymers., Purchased under the trade names "Escorez ^TM ", "Arkon ^TM ", "Clearon ^TM " and the like. Exemplary aliphatic-aromatic blended polymers include those sold under the trade names "Escorez ^™ ,""Regallite ^™ ,""Hercures ^™ ,""AR ^™ ", "Impez ^™ ,""Norsolene ^™ M", "Marukarez ^™ ," Arkon ^TM M "," Quintone ^TM "and the like. Other tackifying agents may be used provided that they are compatible with a uniform linear or substantially linear ethylene / α-olefin copolymer and optional wax.

 The tackifier will usually be present in the hot melt adhesives of the present invention in an amount of less than 70 wt.%, Preferably less than 50 wt.%. The tackifier will typically be present in the hot melt adhesives of the present invention in an amount of at least 5 weight. %, preferably at least equal to 10 wt.%.

The term “wax” is used to mean a paraffinic or crystalline ethylene homopolymer or copolymer or homogeneous ethylene polymers that have a number average molecular weight of less than 6000. Exemplary polymers falling into this category include ethylene homopolymers purchased from Petrolite, Inc. (Tulsa , Oklahoma) under the brands Polywax ^TM 500, Polywax ^TM 1500, and Polywax ^TM 2000; and paraffin waxes purchased from CP Hall under product designations 1230, 1236, 1240, 1245, 1246, 1255, 1260 and 1262. Polywax ^™ 2000 has a molecular weight of approximately 2000 Mw / Mn of approximately 1 , 0, a density at 16 ^{° C.} approximately equal to 0.97 g / cm ³ and a melting point approximately equal to 126 ^° C.

CP Hall 1246 Paraffin Wax can be purchased from CP Hall (Stow, Ohio). Paraffin wax "CP Hall 1246" has a melting point equal to 143 ^o F (62 ^o C), a viscosity at 210 ^o F (99 ^o C) equal to 4.2 cP (4.2 g / cm • s) (4, 2 MPa • s), and the specific gravity at 73 ^o F (23 ^o C), equal to 0.915.

Preferred waxes will be prepared using a geometry limited catalyst. Such polymers will be either ethylene homopolymers or copolymers of ethylene and comonomer, such as the one proposed above with respect to the polymer, for example C ₃ - C ₂₀ α-olefins, styrene, alkyl substituted styrene, tetrafluoroethylene, vinylbenzenecyclobutane, non-conjugated dienes and naphthenic hydrocarbons. Such polymers, in contrast to traditional waxes, will have M _w / M _n in the range from 1.5 to 2.5, preferably from 1.8 to 2.2. Such polymers are described and claimed in US Patent Application Serial No. 784.683, filed on January 22, 1997 (WO 97/01181).

 The wax will have a number average molecular weight of less than 6000, preferably less than 5000. Such waxes will typically have a number average molecular weight of at least 800, preferably at least 1300.

A wax useful for the hot-melt adhesives of the present invention if it is an ethylene homopolymer (either wax as a traditional ethylene homopolymer or as an ethylene homopolymer obtained using a geometry limited catalyst) or a copolymer of ethylene and comonomer selected from the group consisting of C ₃ - C ₂₀ α-olefins, non-conjugated dienes and naphthenic hydrocarbons will have a density of at least 0.910 g / cm ³ . Such second polymers will have a density of not more than 0.970 g / cm ³ , preferably not more than 0.965 g / cm ³ .

 The heteromorphic polymer compositions of the present invention are advantageously used in pressure sensitive adhesives due to the fact that the polymer branches with a higher degree of crystallinity contributes to better retention times in the assembly for the adhesive composition. As the adhesive composition cools, the branch polymer will crystallize while the polymer backbone remains soft and / or flowing. This gives strength to the adhesive during the setting process and reduces the exposure time of the adhesive on the surface before gluing / aging in the assembly.

Hot-melt adhesive (in particular adhesive effective under a press) may also contain oil or other plasticizer, such as an amorphous polyolefin. Oils are commonly used to reduce the viscosity of hot melt adhesives. When used, oils will be present in an amount of less than 25, preferably less than 15, and more preferably less than 10 weight. %, based on the weight of the hot-melt adhesive. Exemplary oil classes include white mineral oil (such as Kaydol ^TM (purchased from Witco) and Shellflex ^TM 371 naphthenic oil (purchased from Shell Oil Company)). In such quantities that the oils will reduce the adhesive character of the hot-melt adhesive to levels contraindicated for the intended use, they should not be used.

Hot melt adhesives of the present invention can be obtained using standard melt mixing procedures. In particular, a heteromorphic polymer composition, a possible tackifier, a possible wax and a possible plasticizer can be mixed in the melt at an elevated temperature (from 150 to 200 ^{° C.} ) in an inert gas atmosphere until a homogeneous mixture is obtained. Any mixing method that results in a homogeneous mixture without degradation of the components of the hot melt will be satisfactory, for example, such as using a heated tank equipped with a mixing device. In addition, a heteromorphic polymer composition, a possible wax, a possible tackifier and a possible plasticizer can be fed to an extrusion coating system for coating a substrate.

Suitable press effective adhesives will exhibit a stickiness to the sample of at least 200 g, more preferably at least 300 g, and most preferably at least 350 g. Suitable press effective adhesives will further exhibit heat resistance which is at least 10 ^° C, preferably at least 15 ^° C, and more preferably at least 20 ^° C, is greater than the corresponding value for press effective adhesives in which the branch polymer and the main polymer pi are used in the mixture, and not in the form of a heteromorphic polymer composition of the present invention.

Suitable adhesive compositions will have a sufficiently low viscosity to allow easy application to the desired substrate. Typically, hot melt adhesives will have a melt viscosity at 350 ^° F (177 ^° C) less than 50,000 cP (50,000 g / cm • s) (50,000 mPa • s), with lower viscosity values generally being preferred.

 The use of heteromorphic polymer compositions of the present invention (especially those in which at least one polymer from the polymer of the main chain or polymer branches will be functionalized by the polar group) will also include, but will not be limited to, gaskets, such as gaskets in car windows , sealing compounds, adhesive compositions, flexible molded products such as soles for shoes, insulation and lining of electric wires and cables, rolled roofs, floor coverings, hoses, burns, automotive parts, and other parts known in the industry in that they require elastomeric materials with adhesion to polar substrates.

 The following examples, which represent representative heteromorphic polymer compositions of the present invention, are provided for purposes of illustration and not for purposes of limitation.

Polymers Used in the Preparation of Example Compositions
Polymer A1 is a substantially linear ethylene / octene copolymer prepared as described in US 5,278,236, which had a measured I _{2 of} 0.94 g / 10 min and a density of 0.869 g / cm ³ .

Polymer A2 is a substantially linear ethylene / octene copolymer prepared as described in US 5,278,236, which had a measured I _{2 of} 3.86 g / 10 min and a density of 0.867 g / cm ³ .

Polymer A3 is a substantially linear ethylene / octene copolymer prepared as described in US 5,278,236, which had a measured I _{2 of} 23.79 g / 10 min and a density of 0.867 g / cm ³
A4 polymer is a substantially linear ethylene / octene copolymer prepared as described in US 5,278,236, which had an I _{2 of} 30 g / 10 min and a density of 0.870 g / cm ³ .

Polymer A5 is a substantially linear ethylene / octene copolymer prepared as described in US 5,278,236, which has a density of 0.870 g / cm ³ and I _{2 of} 18 g / 10 min.

Polymer A6 is a substantially linear ethylene / octene copolymer prepared as described in US 5,278,236, which had a measured I _{2 of} 1 g / 10 min and a density of 0.855 g / cm ³ .

Polymer A7 - is a substantially linear ethylene / 1-octene copolymer, prepared as described in US 5,278,236, which has a density of 0.855 g / cm ³ and I _{2 of} 30 g / 10 min.

Polymer A8 - is an ultra low molecular weight ethylene / octene copolymer prepared as described in US Patent Application Serial No. 784,683, filed January 22, 1997 (WO 97/01181), having a density of 0.855 g / cm ³ and a melt viscosity at 350 ^o F (177 ^o C) of 350 cP (350 g / cm • s) (350 MPa •from).

Polymer A9 - is a substantially linear ethylene / 1-octene copolymer prepared as described in US 5,278,236, which has a density of 0.855 g / cm ³ and a melt index of 0.5 g / 10 min.

Polymer A 10 - is a substantially linear ethylene / 1-octene copolymer prepared as described in US 5,278,272, which had a density of 0.870 g / cm ³ and a melt index of 30 g / 10 min.

Polymer B1 - "HDPE 55500" is an ethylene / butene copolymer supplied by Phillips Petroleum, which had a measured I _{2 of} 49 g / 10 min and a density of 0.955 g / cm ³ .

The polymer B2 - "Marlex 50" - 100 - high density polyethylene having a density equal to 0.952 g / cm ³ and I ₂ equal to 0.08 g / 10 min, purchased from the company "Phillips".

The polymer B3 - "Dowlex ^TM 25355" - high density polyethylene having a density equal to 0.955 g / cm ³ and I ₂ equal to 25 g / 10 min.

The polymer B4 - "Dowlex ^TM 25455" - high density polyethylene having a density equal to 0.955 g / cm ³ and I ₂ equal to 25 g / 10 min.

Polymer B5 is a substantially linear ethylene / 1-octene copolymer prepared as described in US 5,278,236, which had a density of 0.902 g / cm ³ and a melt index of 30 g / 10 min.

Polymer B6 is a substantially linear ethylene / 1-octene copolymer prepared as described in US 5,278,236, which had a density of 0.913 g / cm ³ and a melt index of 30 g / 10 min.

The polymer B7 is Attane ^TM 6152, ultra low density polyethylene, a non-uniform linear ethylene / 1-octene copolymer having a density of 0.904 g / cm ³ and a melt index of 0.5 g / 10 min.

Polymer B8 — An ultra low molecular weight ethylene / octene copolymer prepared as described in US Patent Application Serial No. 784,683, filed January 22, 1997 (WO 97/01181), having a density of 0.955 g / cm ³ and a melt viscosity at 350 ^o F (177 ^o C) of 5000 cP (5000 g / cm • s) (5000 mPa •from).

The polymer B9 is a Dow high density polyethylene "HDPE 12165" having a density of 0.955 g / cm ³ and a melt index of 1.0 g / 10 min.

The polymer B10 is a Dow HDPE 25355 high density polyethylene having a density of 0.955 g / cm ³ and a melt index of 10 g / 10 min.

Polymer C is a polymer mixture obtained in a reactor, obtained in accordance with the procedure of WO 94/17112, which has as its target composition: 68.5 wt.% Essentially linear ethylene / octene copolymer having a density of 0.861 g / cm ³ and I ₂ equal to 0.29 g / 10 min, and 31.5 weight. % high density polyethylene having a density equal to 0.946 g / cm ³ and I ₂ equal to 370 g / 10 min.

Polymer D is maleic anhydride grafted high density polyethylene having a density of 0.953 g / cm ³ and a melt index of 9 g / 10 min and 1.2 wt.% Maleic anhydride obtained by the reaction during extrusion of polyethylene high density, having a density equal to 0.953 g / cm ³ with maleic anhydride.

 Lupersol 500R (99% pure dicumyl peroxide purchased from Elf Atochem). Lupersol -130 (90 - 95% 2, 5 - dimethyl - 2, 5-di (tert-butyl peroxy) hexine - 3, purchased from Elf Atochem). Lupersol-101. 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane (purchased from Elf Atochem).

Testing methods used in evaluating the compositions of examples and comparative examples
Operating temperature under load (ULST) is measured using a thermomechanical analyzer (TMA). The penetration depth was measured as a function of temperature. The temperature during penetration of the probe to a depth of 1 mm is taken as the softening temperature under load. A heating rate of 5 ^° C./min and a load of 102 g were used.

The RSAII model solid state rheometer was used to determine the change in modulus with temperature. Samples were obtained by direct compression in the form of films with a thickness of approximately 0.25 mm, as a result of incubation of 1500 psi (10.3 MPa) and 350 ^o F (177 ^o C) for 5 min and subsequent cooling at 27 ^o F / min (-2.8 ^o C / min) to 90 ^o F (32 ^o C). Samples were kept at 90 ^o F (32 ^o C) for 1 min and after that they were removed from the press. A sample was cut with approximate dimensions of 0.25 x 4.4 x 22 mm and then it was used for testing under the following conditions: frequency 10 rad / s in a torsion test of a rectangle, starting from - 145 ^o С with an increase up to 120 ^o С or 150 ^o C or 270 ^o C with a step size of 5 ^o With the exposure time at each step equal to 30 s in a nitrogen atmosphere.

 The gel content was determined by extraction in xylene in accordance with ASTM D 2785, Procedure A.

The stress and strain at 23 ^o C and 70 ^o C were measured in accordance with ASTM D - 1708. The values in brackets represent the stress and strain at 70 ^o C.

 Shore A hardness was measured in accordance with ASTM D2240.

 The tensile strength was measured in accordance with ASTM D - 1708 using micro-tension bars.

The melt viscosity was determined in accordance with the following procedure using a Brookfield Laboratories DVII + laboratory viscometer in disposable aluminum sample chambers. The spindle used was the SC - 31 hot melt spindle, suitable for measuring viscosities in the range of 10 to 100,000 cP (10 to 100,000 g / cm • s) (10 to 100,000 mPa • s). A cutting blade was used to cut the samples into pieces small enough to fit a sample chamber with a width of 1 inch (2.5 cm) and a length of 5 inches (12.5 cm). The sample is located in a chamber, which in turn is inserted into the Brookfield Thermosel and fixed in this position with curved nippers. The sample chamber has a notch in the lower part that corresponds to the lower part of the Brookfield Thermosel in order to ensure that the chamber cannot be rotated when the spindle is inserted and rotated. The sample is heated to 350 ^° F. (177 ^{° C.} ), an additional sample is added until the molten sample is approximately 1 inch (2.5 cm) below the top of the sample chamber. The viscometer is lowered and the spindle is immersed in the sample chamber. Lowering continues until the consoles on the viscometer align with the Thermosel. The viscometer is turned on and set to shear rate, which leads to indications for torque in the range from 30 to 60%. The readings are taken every minute for approximately 15 minutes or until the values stabilize, the final reading of which is recorded.

 Examples 1-3: determining the amount of branch polymer that reacts to form the heteromorphic polymer compositions of the present invention.

A viscometer with a Haake Rheocord System 40 coaxial cylinder with a Rheonux 600 mixer and roller-type mixing blades was used to prepare the compositions of these examples. The mixtures were obtained by mixing the components at 75 rpm at 145 ^o C. The compositions of the polymers A2, A3 and B were presented above. In the indicated amount, Lupersol 500 (99% pure dicumyl peroxide purchased from Elf Atochem) was added and the resulting mixture was stirred for approximately 1 minute at 145 ^° C, the temperature was increased to 175 ^° C, and the sample was mixed for a total of 15 minutes Samples were placed on a cold plate of a direct compression press while still hot, and pressed to obtain a thin film for FTIR analysis of the vinyl group content.

 FTIR testing of representative compositions of the present invention are given in table 1.

 A decrease in the concentration of terminal vinyl groups can be considered as an indicator of the degree to which the formation of T-shaped compounds takes place. Due to the fact that the detachability of the hydrogen atom from the polymer A2 and A3 can presumably be characterized by approximately the same probability as the detachability of the hydrogen atom from the polymer B1 due to the fact that a larger part of the vinyl groups is on polymer B1 with a lower molecular weight, rather than on polymers A2 and A3 with a higher molecular weight (provided that a mixture of polymer components of 50: 50 is used), it can be assumed that approximately 50% of the formed T-shaped compounds result from ate B1 polymer grafting on the polymers A2 and A3. The strong decrease in the concentration of vinyl groups, shown in Table 1, is additional evidence of the formation of T-shaped compounds. The attachment of polymer B1 with a higher degree of crystallinity to the main chain is confirmed by a dramatic improvement in temperature resistance, described in the following examples.

 Examples and comparative examples 4 to 18: improving the resistance to temperature, manifested by the heteromorphic polymer compositions of the present invention.

A viscometer with a Haake Rheocord System 40 coaxial cylinder was used with a Rheomix 3000E mixer and stirring blades of a roller type. Samples were obtained by melt blending of polymer B1 and any polymer from polymers Al, A2 and A3 at rpm in the range of 60 to 75 and at about 145 ^{° C.} for about 4 minutes. Lupersol 500R (99 percent pure dicumyl peroxide purchased from Elf Atochem) was added in the indicated amounts. The speed of the mixer was increased to approximately 160 rpm for vigorous stirring with peroxide, thereby causing the effect of viscous heating, which for 1-2 minutes increased the temperature of the mixture to approximately 190 ^o C, which entailed the decomposition of peroxide. The mixer speed was reduced to 60 rpm for another next minute. After stirring, the mixer stopped and the sample was removed and allowed to cool. After this, granulation of polymer lumps was carried out.

Tab. 2 shows that the mixture of comparative example 15, that is, the mixture that was not treated with peroxide, breaks down at approximately 70 ^° C. As a result of the melting of crystallites of polymer A3, the mixture does not have sufficient strength to maintain its integrity during testing using RSA, and the sample is destroyed. In contrast, the heteromorphic polymer composition of Example 15, that is, the composition that was subjected to peroxide treatment, retained its integrity up to 130 ^{° C.} , which approximately corresponds to the melting temperature of polymer B1.

 Tab. 2 summarizes the results for a series of comparative blended compositions (obtained without peroxide treatment) and for a series of heteromorphic polymer compositions of the present invention (obtained using peroxide treatment). Tab. 2 shows that the heteromorphic compositions of the present invention are characterized by significantly improved temperature resistance with respect to comparable mixtures. In addition, Table 2 demonstrates that the pure Al, A2, and A3 polymers that have been treated with peroxide, in turn, are destroyed at relatively low temperatures. Thus, a significant improvement in temperature resistance for the heteromorphic polymer compositions of the present invention cannot be attributed to the formation of a crosslinked network, but rather can be attributed to the attachment of branches of polymer B1 with a high melting point to the main chain formed by polymers Al, A2 and A3.

 Examples 19-23: the effect of peroxide on the physical properties of heteromorphic polymer compositions.

 Heteromorphic polymer compositions of comparative examples and examples 19-23 were obtained in accordance with the procedures proposed above in examples 1-4. The compositions of heteromorphic polymer compositions and comparable mixtures, as well as the resulting properties, are shown in Table 3.

Discussion of examples 19-21. With regard to examples 19-21, we can say that as the amount of peroxide increased, the operating temperature under load increased in the same way, by 27 ^° C in the case of Example 20 and by 47 ^° C in the case of Example 21. The results shown in table 3 demonstrate that the heteromorphic polymer compositions of the present invention of examples 20 and 21 are characterized by much higher heat resistance compared to the corresponding comparable mixture of comparative example 19. This conclusion follows from figure 3, which illustrates then the heteromorphic polymer compositions of examples 20 and 21 better tolerate the effect of temperature with respect to reducing Shore A hardness to a value less than 45, when compared with comparative example 19. This is further demonstrated in figure 4, which shows that the heteromorphic polymer compositions of examples 20 and 21 undergo penetration of the probe to a depth of 1 mm at higher temperatures compared to comparative example 19.

Tab. 3 also indicates that heteromorphic polymer compositions have tensile properties at elevated temperatures that exceed the corresponding characteristics for comparable mixtures of comparative example 19. For example, the mixture of comparative example 19 loses most of its tensile strength at 70 ^° C. B contrast, the heteromorphic polymer compositions of examples 20 and 21 exhibit tensile strengths at 100 ^o C, equal to 250 psi (1,72 MPa) and 180 psi (1,24 MPa) Correspondingly enno.

 Moreover, the gel content in heteromorphic polymer compositions in Examples 20-21 is less than in partially wired mixtures of the prior art, see, for example, U.S. 3,806,558, which describes a gel content in excess of 30%. Surprisingly, heteromorphic polymer compositions exhibit such a large improvement in high temperature properties without significantly reducing flexibility and softness and without the formation of significant amounts of a wired mesh structure.

Discussion of examples 21-23. As regards Examples 21-23, it can be said that the operating temperature under load increased as the concentration of the polymer with a higher degree of crystallinity forming the branches increased. It is interesting to note that, as follows from a comparison of the results for examples 23 and 21, an increase in the amount of material with a higher degree of crystallinity from 20 to 25 wt.% Leads to an increase in the operating temperature under load by 40 ^o C.

Discussion of examples 24-25. Examples 24 and 25 illustrate the fact that mixtures of a higher crystallinity polymer and a lower crystallinity polymer obtained in a reactor can advantageously be converted to heteromorphic compositions of the present invention. Note that the heteromorphic polymer composition of Example 25 detects a working temperature under load that is 40 ^° C higher than the corresponding temperature for the unreacted mixture of Comparative Example 24 obtained in the reactor.

The study using micrographs obtained by transmission electron microscopy (TEM), heteromorphic polymer compositions of examples and comparative examples 19 to 20 and 24 to 25:
Heteromorphic polymer compositions and comparative mixtures were converted by direct compression into disks with an inner diameter of 1 inch (2.5 cm) and a thickness of 1/16 inch (0.16 cm) at a molding temperature of 177 ^° C, after which they were cooled to 22 ^° C at a rate of 15 ^° C / min before being taken out of the mold.

Thereafter, strips of the samples obtained by direct compression were placed in an “Epofix” (Struer epoxy resin insert kit) at room temperature. After cutting the piece, the samples were etched with a mixture of ruthenium trichloride and a Clorox ^™ bleaching agent for two hours at room temperature. Ultra-thin sections with a thickness of approximately 1000 angstroms were collected at room temperature using a Reichert-Jung Ultracut E microtome. Sections were placed on a copper mesh for a sample coated with formvar.

 Cross sections were studied using a "JEOL 2000FX TEM" operating at an accelerating voltage of 100 kV and an increase of 30,000 times.

 Digital conversion of TEM images was carried out using the Leica Quantimet 570 gray scale analyzer. Images in the gray scale were imported using a charge-coupled camera with amplification and zero position of the amplifier, individually set for each image. Two-level images containing the dispersed phase and individual lamellas were obtained by adjusting the threshold for the gray scale. These two-level images were morphologically opened using horizontal and vertical operators with a size of 1 to remove individual lamellas from the matrix. The background noise was removed by morphological opening with a disk of size 2. After that, manual editing was undertaken to correct the remaining errors. For a description of the image transformations used, see "Image Analysis and Mathematical Morphology", vol. 1, by Jean Serra, Academic Press (1982).

 The digital image converter measured eight diameters from each particle of the dispersed phase and the fraction of the total area from two-level images. Statistical diameters were calculated using the average diameter for each particle of the dispersed phase. These statistical diameters carried with them information regarding the phase size and the width of the size distribution. The diameter, weighted average by volume, reflected the presence of large particles, while the harmonic mean for the diameter reflected the presence of small particles.

 The image obtained by the TEM method for comparative example 19 is shown in FIG. 5 with an increase of 30,000 times. The micrograph shows a two-phase morphology consisting of dispersed polyethylene domains with a higher degree of crystallinity in the continuous matrix of the elastomeric phase attributed to polymer A3. Domains attributed to component B2, which is a polyethylene with a higher density, can be identified due to the presence of lamellar morphology, both within its phase and manifesting itself in the form of rays emanating from the matrix phase. The elastomeric phase attributed to the component by polymer A3, which is a lower density polyethylene, exhibits a characteristic morphology with granules from fringe micelle crystallites. In contrast, a TEM image for the heteromorphic polymer composition of Example 20 is shown in FIG. 6 at a magnification of 30,000 times. While the micrograph shows the presence of a two-phase morphology, the average domain size of the dispersed phase of the higher density polyethylene attributed to polymer B2 has decreased significantly compared to the corresponding value in FIG. 5. A good dispersion of the lamellas in the elastomeric phase is consistent with the view that component B2, which is a higher density polyethylene, is grafted onto the elastomeric backbone formed by polymer A3. Images obtained by the TEM method for comparative example 24 and example 25 at a magnification of 30,000 times are shown in FIGS. 7 and 8.

 The volume fraction of the dispersed phase of the higher density polyethylene was determined by digital image conversion. The volume and size of the dispersed phase of high density polyethylene in comparable mixtures and in heteromorphic polymer compositions are given in table. 4.

 As shown in table 5, heteromorphic polymer compositions of example 20 of the present invention are characterized by the presence of more than 50% fewer islands with a higher degree of crystallinity (as evidenced by a significantly lower volume percent) compared to unreacted mixtures of comparative examples 19. Similarly heteromorphic polymer compositions of example 25 of the present invention are characterized by the presence of 67% fewer islands with a higher degree of crystallinity (as evidenced by elstvuet significantly lower volume percent) as compared with the unreacted blends of Comparative Examples 24. This suggests that the heteromorphic compositions of the present invention actually contain elastomer backbones to which was grafted a component - a polymer with a high density.

 The average volume percent for comparative examples 19 and 24 is 22.1%. The average volume percent for examples 20 and 25 is 8. Based on this, it is estimated that 64% of the total amount of higher density polyethylene is grafted onto the elastomeric backbone.

Examples 26 and 27: heteromorphic ethylene polymers for press effective adhesives
The following polymers are used in the preparation of heteromorphic polymer compositions of this example:
Samples were obtained by melt blending of A6 and D polymers in the indicated amounts in a viscometer with a Haake Rheocord System 40 coaxial cylinder with a Rheomix 3000E mixer and roller-type mixing blades at rpm between 60 and 75 and approximately at 145 ^{° C.} for approximately 4 minutes Lupersol ^TM 101 (purchased from Elf Atochem) was added in the indicated amounts, and the mixer speed was increased to about 160 rpm for intensive mixing with it and to create the effect of viscous heating, which increased the temperature for 1-2 minutes up to approximately 190 ^o With for the decomposition of peroxide. The mixer speed was reduced to 60 rpm for another next minute. After stirring, the mixer stopped and the sample was removed and allowed to cool. After this, granulation of polymer lumps was carried out.

The resulting heteromorphic polymers and a comparable polymer blend were tested for performance as a press effective adhesive for tape. The following adhesive compositions were used: 100 parts of polymer per 100 parts of polymer, 220 parts of tackifier "Escorez 1310 LC" per 100 parts of polymer and 1 part of "Irganox ^TM 1010" per 100 parts of polymer. The components of the composition were melt blended at 130 ^° C in "Haake". After obtaining a homogeneous mixture using a syringe, 80 parts of Kaydol oil per 100 parts of polymer were added. Tape samples were obtained by direct compression of the obtained adhesive compositions between the Mylar ^TM film and the release liner at 170 ^° C under a pressure of 20,000 psi (138 MPa). The resulting glue thickness was approximately 2 mils (0.05 mm).

The heat resistance of the resulting adhesive composition was measured using a Rheometrics, Inc., RDA-II dynamic mechanical spectrometer. The temperature at which the storage modulus (G ') for a plateau of high elasticity sharply decreased was taken as the heat resistance temperature. Passage through the temperatures was carried out from approximately -70 to 200 ^o С from 5 ^o С / step with a 30 s delay to achieve equilibrium at each step . The oscillation frequency was 1 rad / s with the auto-deformation function, initially before deformation of 0.1%, increasing the forced regulation by 100% each time the torque was reduced to 4 g / s. Maximum deformation was set at 26%. Clamps with 7.9 mm parallel plates were used with an initial gap of 1.5 mm at 160 ^° C (the sample was inserted into the "RDA-II" at 160 ^° C). At 160 ^o С, the “Hold” function was activated, and the device was cooled to - 70 ^o С, testing began, this introduced a correction for thermal expansion or compression when the testing chamber heats up or cools down. During the experiment, the sample was in a nitrogen atmosphere to minimize oxidative degradation.

 The stickiness to the sample was measured in accordance with ASTM D - 2979 - 71 using a holding time of the material under pressure of 10 s and a sample separation rate of 1 cm / s.

The viscosity at 177 ^{° C.} was measured in accordance with the following procedure using a Brookfield Laboratories DVII + viscometer in disposable aluminum sample chambers. The spindle used was the SC-31 hot melt spindle. The samples were cut into pieces small enough to fit a sample chamber with a width of 1 inch (2.5 cm) and a length of 5 inches (12.5 cm). The sample is heated to 350 ^° F. (177 ^{° C.} ) so that the molten sample is approximately 1 inch (2.5 cm) below the top of the sample chamber. The viscometer is lowered and the spindle is immersed in the sample chamber. The viscometer is turned on and set to shear rate, which leads to indications for torque in the range from 30 to 60%. The readings are taken every minute for approximately 15 minutes or until the values stabilize, the final reading of which is recorded.

 Heteromorphic polymer compositions and comparable polymers, their properties and operational characteristics for use as adhesive compositions effective under pressure are given in Table 5-7.

 The results in the table. 5 indicate that heteromorphic polymers can be used as press effective adhesives: the sample has acceptable processability, sample stickiness (comparable to the commercially available Scotch Magic tape) and a higher temperature of use compared to a comparable mixture.

The TMA data given in Table 7 suggest that the upper temperature of the use of heteromorphic polymer compositions exceeds the corresponding value for comparable unvaccinated samples. Compare, for example, examples 21-2 with 21-3, and 21-4 with 21-5. Sample stickiness results suggest that the compositions of the present invention have acceptable stickiness, i.e., have a stickiness to the sample of at least 200 g, more preferably at least 300 g, and most preferably at least 380 g. Data according to G 'and T _g suggest that heteromorphic polymer compositions can be used in pressure sensitive adhesives, that is, they are characterized by the presence of G' in the range from 10 ⁵ to 10 ⁶ dyne / cm ² (from 0.01 to 0, 1 MPa) and Tg in the range from -10 to 10 ^o C. The examples from table 7 demonstrate the flexibility of the technology of the present invention, that is, the molecular weight and density of the polymer of the main chain and polymer branches can be changed to obtain compositions suitable for use in a variety of applications for adhesives that are sensitive to pressure.

 Examples 40-41: functionalization to improve adhesion to glass.

Samples were obtained by extrusion with the simultaneous reaction of polymers A10 and B4 (in the case of example 40) and polymers A10 and D (in the case of example 41). In each case, the polymer reagent mixture was impregnated with peroxide, and the impregnated sample was extruded in a twin-screw extruder at 210 ^° C. The resulting compositions were evaluated with respect to the upper temperature of use, shear adhesion and shear adhesion under T-peeling .

Lap shear adhesion was determined by directly compressing the test polymer at 350 ^° F (177 ^° C) between two microscope slides, attaching the slides with a sponge tape, and then conducting a tensile shear tensile test on the Instron tensiometer.

Shear adhesion during T-peeling was determined as follows. Slides (dimensions: 3 x 1 x 0.05 inches (7.6 x 2.5 x 0.12 cm) from Fisher Scientific) were glued to strips of cold rolled steel (CRS, dimensions: 6 x 1 x 0.032 inches (15 x 2.5 x 0.08) from Q - Panel Company) using the Loctite Depend Adhesive (part number 00206, from Loctite Corporation) by applying a surface activator to a CRS strip and adhesive polymer composition on a glass slide. When the slide and CRS were joined together, the adhesive was sufficiently mixed. These bonded joints were exposed to a load of 10 pounds (22 kg) for 10 minutes. CRS strips / slide were placed on a hot plate (180 ^o C). Test strips HDPE - g - EO and a second metal strip were placed on CRS / slide strips located on the hot plate. They were heated until the polymer sample was melted. After that, they were cooled to room temperature. Test samples were tested 24 hours after their receipt.

 Using the Instron 4204 material testing system in accordance with ASTM method D1876 - 72, the nominal strain dependences were obtained. The spacing between the grippers was 2 inches (5 cm), and the speed of the guide heads was 10 inches / min (25 cm / min).

 Heteromorphic polymer compositions and the resulting properties are given in table 8.

 The adhesion to glass of a heteromorphic polymer composition is significantly increased when using the grafted MAN - g - HDPE polymer instead of HDPE as the branch polymer. The results in Table 8 indicate that the grafted heteromorphic composition MAH-g-HDPE has much higher adhesion to shear lap joint and shear adhesion under T-peeling to glass than a non-functionalized heteromorphic polymer composition.

 As demonstrated in the discussion above for adhesive composition 21-9, heteromorphic polymer compositions functionalized with maleic acid can advantageously be used in pressure sensitive adhesive compositions.

 The invention, described above in full detail and illustrated by examples, is limited only in accordance with the following claims.

Claims (16)

1. Heteromorphic polymer composition, characterized in that it contains: (a) a main chain obtained from a polymer of the main chain, which is a homogeneous linear or essentially linear ethylene / α-olefin copolymer, and (b) a side chain attached to the main chain, and the side chain is obtained from the polymer of the side chain, which is an ethylene homopolymer or ethylene / α-olefin copolymer having a density that is at least 0.004 g / cm ³ higher than the density of the polymer of the main chain, and having more than a high degree of crystallinity compared to the degree of crystallinity of the polymer of the main chain. 2. Heteromorphic polymer composition according to claim 1, where the main chain is obtained from a polymer of the main chain, which is a homogeneous linear or essentially linear ethylene / α-olefin copolymer having a density of less than 0.920 g / cm ³ . 3. A heteromorphic polymer composition according to claim 1, wherein the side chain is characterized in that it is obtained from an ethylene homopolymer or an ethylene / α-olefin copolymer having a density that is at least 0.006 g / cm ³ higher than the density for the main chain. 4. A heteromorphic polymer composition according to claim 1, wherein the main chain polymer is characterized in that it is obtained from a homogeneous linear or substantially linear ethylene copolymer and at least one C ₃ -C ₂₀ α-olefin. 5. The heteromorphic polymer composition according to claim 4, wherein the homogeneous linear or substantially linear copolymer from which the main chain is obtained is further characterized in that it has a CDI of at least 50 and M _w / M _{n of} less than 3. 6. Heteromorphic polymer composition according to any one of the preceding paragraphs, where the main chain copolymer is characterized in that it is obtained from a substantially linear copolymer, characterized in that it has: (a) melt flow coefficient, I ₁₀ / I ₂ ≥ 5.63; (b) a molecular weight distribution, M _w / M _n , determined by gel permeation chromatography and determined by the equation (M _w / M _n ) ≤ (I ₁₀ / I ₂ ) -4.63; (c) the critical shear stress at the time of the beginning of the total destruction of the extrusion flow, as determined by gas extrusion rheometry, exceeding 4 • 10 ⁶ dyne / cm ² (0.4 MPa), or gas extrusion rheology, such that the critical shear rate at the moment the onset of surface fracture of the extrusion flow for a substantially linear ethylene copolymer would be at least 50% greater than the critical shear rate at the start of the surface fracture of the extrusion flow for a linear ethylene polymer, de substantially linear ethylene copolymer and the linear ethylene polymer comprise the same comonomer or comonomers, the linear ethylene polymer has an I _2, M _w / M _n and density within 10% of the corresponding values for substantially linear ethylene copolymer and wherein the corresponding critical shear rates for a substantially linear ethylene copolymer and for a linear ethylene polymer are measured at the same melt temperature using a gas extrusion plastomer, and (d) a single peak phenomenon, determined by the method of differential scanning calorimetry, DSC, between - 30 and 150 ^o C.  7. Heteromorphic polymer composition according to any one of the preceding paragraphs, where the main chain copolymer is characterized in that it is obtained from a substantially linear ethylene / α-olefin copolymer, which as substituents has an average of from 0.01 to 3 branches with a long chain / 1000 carbon atoms. 8. Heteromorphic polymer composition, characterized in that it contains the reaction product (a) from 40 to 5 weight. % of the polymer forming the side chain, and this side chain contains an ethylene homopolymer or ethylene / α-olefin copolymer, and (b) from 60 to 95 weight. % of the material that forms the main chain, which is ethylene and one or more α-olefin comonomer or which is a homogeneous linear or essentially linear ethylene / α-olefin copolymer, and where the crystallinity of the polymer forming the side chain, at least 5% exceeds the crystallinity of the material forming the main chain, and where the heteromorphic polymer composition has an upper temperature limit of use, which is at least 10 ^o exceeds the corresponding temperature for an unreacted mixture of a polymer forming a side chain and a material forming a main chain.  9. The heteromorphic polymer composition according to any one of the preceding paragraphs is further characterized in that it contains groups obtained by grafting the polar group onto at least one polymer forming the main chain or a side chain polymer.  10. A method of producing a heteromorphic polymer composition according to any one of the preceding paragraphs, characterized in that it comprises the steps of: (a) polymerizing ethylene and possibly one or more α-olefin comonomers under reaction conditions to form a polymer forming a side chain; (b) polymerizing ethylene, one or more α-olefin comonomers and a polymer forming a side chain, from step (a) under reaction conditions, to obtain a heteromorphic polymer composition, wherein the crystallinity of the polymer forming the side chain at room temperature is at least 5% higher than the crystallinity of the polymer forming the main chain.  11. The method according to p. 10, where the polymerization (a) is carried out in the first reactor, and the polymerization (b) is carried out in the second reactor, or where the polymerization (a) is carried out in the same reactor as the polymerization (b), and where the first the catalyst is used during the polymerization (a), and the second compatible catalyst is used during the polymerization (b).  12. A method for producing a heteromorphic polymer composition according to any one of the preceding paragraphs, characterized in that it comprises the steps of: (a) polymerizing ethylene and possibly one or more α-olefin comonomers under reaction conditions to obtain a reaction stream containing a polymer forming a side chain ; (b) polymerizing ethylene and one or more α-olefin comonomers to produce a reaction stream containing a uniform linear or substantially linear polymer that forms a backbone; (c) possible isolation of the polymer forming the side chain from the reaction stream (a) and the polymer forming the main chain from the reaction stream (b) and (d) carrying out the reaction of the polymer forming the side chain and the polymer forming the main chain, c the presence of a free radical initiator in order to attach the polymer forming the side chain to the polymer forming the main chain to obtain a heteromorphic polymer composition; moreover, the polymer forming the side chain has a degree of crystallinity at room temperature, which is at least 5% higher than the crystallinity of the polymer forming the main chain.  13. The method according to p. 12, where the reaction in stage (d) is performed before the isolation of the polymer forming the side chain and the polymer forming the main chain from the stream of reaction products c (a) and (b), and the method further comprises the step (e) isolating the heteromorphic polymer composition from the combined reaction product stream.  14. Heteromorphic composition according to or obtained according to any one of the preceding paragraphs in the form of an adhesive composition, sealant, coating, molded product, film, thermoformed product or fiber.  15. The composition of the hot-melt adhesive containing a heteromorphic composition according to or obtained according to any one of the preceding paragraphs. 16. The hot-melt adhesive composition according to claim 15, characterized in that it has a stickiness to the sample of at least 200 g and an upper temperature limit of use, which is at least 10 ^° C higher than the corresponding temperature for a hot-melt adhesive containing unreacted a mixture of the polymer of the side chain and the polymer of the main chain, provided that equal amounts are present in the heteromorphic polymer composition.

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