MXPA97003224A - Composition of molding, method of preparation, method of molding, and articles moldea - Google Patents

Abstract

A glossy molding composition comprising: A) from 95 to 65% by weight, based on the weight of A) and B), of a homopolymer or ethylene interpolymer having a density of 0.955 g / cm3 or greater, an index of fusion of 0.3 to 10 g / 10 min, and a polydispersity of 1.8 to 10, and B) of 5 to 40% by weight, based on the weight of A) and B), of a linear or substantially linear ethylene interpolymer that it has a density of 0.85 to 0.93 g / cm3, a melting index of 0.5 to 5 g / 10 min, and a polydispersity of 1.8 to 5, where the composition has a density of 0.94 to 0.962 g / cm3. A process for preparing this composition, a method of manufacturing molded articles, by molding said composition, and a molded article obtained by said process

Description

COMPOSITION OF MOLDING. PREPARATION METHOD. MOLDING METHOD. AND MOLDED ARTICLES FIELD OF THE INVENTION The present invention relates to a molding composition comprising a high density ethylene homopolymer or interpolymer and a low density ethylene interpolymer, to a process for its preparation, to a process for making molded articles using said composition, and to Molded articles obtained through this procedure.

BACKGROUND OF THE INVENTION The molding of polyethylene and polyethylene compositions to variously shaped articles, such as films and bottles, is known using molding techniques, such as injection molding, blow molding, and extrusion molding. In the packaging industries, there is a desire to use bottles and other containers that look bright. In addition to a shiny appearance, said container must also have certain mechanical and chemical properties. For use in a blow molding technique, a high density polyethylene is usually used, in view of the desired stiffness of the container. These high density polyethylenes (HDPE), however, have poor gloss properties. Therefore, typically an HDPE is coextruded with a free radical polymerized low density polyethylene (LDPE), as an outer layer, to provide a container having both stiffness and good gloss properties. Sayings co-extruded containers, in addition to requiring more complicated production equipment and procedure, have poor scratch resistance due to the low density of the LDPE outer layer. In addition, it has been proposed to use specific processing aids with improved brightness characteristics, such as processing aids of the fluorocarbon or organosilicon elastomer type. However, these specific processing aids are relatively expensive and often require a long preconditioning of the processing equipment. The Japanese patent application published 64-87226 (March 31, 1989) describes a method for manufacturing hollow molded articles using a die from which part (including the tip) or the entire inner surface is made from a resin molding. fluorine and a composition consisting of 30 to 90% by weight of : > or high density polyethylene, with a density of at least 0.946 g / cm3, and a melt index of 0.01 to 3.0 g / 10 min, and 70 to 10% by weight of a low or medium density polyethylene, straight chain, which has a density of 0.910 to 0.940 g / cm3, and a melt index of 0.1 to 10.0 g / 10 min, and a polydispersity (Mw / M ") of 6.0 or less. According to the examples and comparative examples of this reference, a mixture of 70% by weight of high density component with a density of 0.955 g / cm 3 and a melt index of 0.3 g / 10 min, and 30% is used. by weight of a low density polyethylene having a density of 0.925 g / cm3, a melt index of 0.7 g / 10 min, and a polydispersity of 5.0. A good surface gloss was obtained with said mixture when the die was coated with a fluorine coating resin. Japanese patent application published 03-115341 (May 16, 1991) discloses a container having an external surface consisting of 25 to 75% by weight of LLDPE with a melt index of 1.0 to 3.0 g / 10 min and a density up to 0.935 g / cm3, with 75 to 25% by weight of an HDPE with a melt index of 0.1 to 1.5 g / 10 min and a density of at least 0.942 g / cm3. In one example, a composition of 25% by weight of LLDPE, having a melt index of 2.1 g / 10 min and a density of 0.935 g / cm3, and 75% HDPE, with a melt index of 0.4 g / 10 min and a density of 0.958 g / cm3, it was molded by extrusion by blowing to obtain a bottle with improved brightness and increased coefficients of static and dynamic friction, compared to bottles produced only from HDPE. Japanese patent application published 05-310241 (November 22, 1993) discloses hollow molded polyethylene resin containers, wherein a polyethylene composition with a melt index of 1.0 to 10 g / 10 min ranging from 95 to 20% by weight of an ethylene homopolymer or an ethylene / α-olefin interpolymer, with a melt index of 0.1 to 3.0 g / 10 min, a density of 0.9400 more, and a polydispersity of 5.0, and from 5 to 80% in Weight of an ethylene / α-olefin interpolymer with a melt index of 0 to 50 g / 10 min and a density of 0.935 or less is used for at least the outer surface layer for the molded container. Preferred compositions have a melt index of 2.0 to 6.0 g / 10 min and contain 80 to 30% by weight of a high density component having a melt index of 0.1 to 2.0 g / 10 min, a density of 0.945 at 0.970, and a polydispersity of 5.5 to 15, and 25 to 70% by weight of a low density component having a melt index of 3.0 to 30 g / 10 min, and a density of 0.900 to 0.930. Examples and comparative examples show that a low density component, having a melt index of less than 3.0, gives a poor brightness value. The present invention relates to compositions that can be molded to articles having improved gloss and impact resistance, while maintaining adequate levels of stiffness, when compared to the state of prior art HDPE molding compositions. The present invention furthermore relates to compositions that can be molded into articles, essentially with the same equipment used by the molding of HDPE compositions of the prior art, without requiring specific coatings on the die and without requiring the use of processing aids more. costly fluorocarbon elastomer or organosilicon type.

COMPENDIUM OF THE INVENTION In one aspect, the present invention provides a molding composition comprising: A) from 95 to 60% by weight, based on the weight of A) and B), of a homopolymer or ethylene interpolymer, having a density of 0.955 g / cm3 or greater, a melt index of 0.3 to 10 g / 10 min, and a polydispersity of 1.8 to 10; and B) from 5 to 405 by weight, based on the weight of A) and B), of a linear or substantially linear ethylene interpolymer, having a density of 0.85 to 0.93 g / cm 3, a melt index of 0.5 to 5 g / 10 min; and a polydispersity of 1.8 to 5; wherein the composition has a density of 0.94 to 0.964 g / cm3. According to a further aspect, the invention provides a method for preparing a molding composition by mixing: A) from 95 to 60% by weight, based on the weight of A) and B), of a homopolymer or ethylene interpolymer, having a density of 0.955 g / cm3 or greater, a melt index of 0.3 to 10 g / 10 min, and a polydispersity of 1.8 to 10; and B) from 5 to 40% by weight, based on the weight of A) and B), of a linear or substantially linear ethylene interpolymer having a density of 0.85 to 0.93 g / cm 3, a melt index of 0.5 to 5 g / 10 min, and a polydispersity of 1.8 to 5; wherein the composition has a density of 0.94 to 0.962 g / cm3. According to a further aspect, the invention provides a method for manufacturing molded articles, molding the composition of the present invention. According to a final aspect, the invention provides a molded article obtained through the process for the manufacture of molded articles.

DETAILED DESCRIPTION OF THE INVENTION All references herein to elements or metals belonging to a certain Group refer to the Periodic Table of the Elements published and registered by CRC Press, Inc., 1989. Also, any reference to the Group or Groups must be made to the Group or Groups as they are reflected in this Periodic Table of the Elements using the IUPAC system to renumber the Groups. The term "polymer", as used herein, refers to a polymeric compound prepared through the polymerization of one or more monomers. The generic term "polymer" in this manner embraces the term "homopolymer", usually used to refer to polymers prepared from a single monomer, and the term "interpolymer" as defined above. The term "interpolymer", as used herein, refers to polymers prepared through the polymerization of at least two different monomers. The generic term interpolymer in this manner encompasses copolymers, which are usually used to refer to polymers prepared from two different monomers, and polymers prepared from more than two different monomers. Since a polymer or interpolymer comprising or containing certain monomers is described in the present invention, it means that said polymers or interpolymers comprise or contain, polymerized therein, units derived from said monomer. For example, if the monomer is ethylene CH2 = CH2, the derivative of this unit as incorporated in the polymer is -CH2-CH2-. Where the melt index values are specified in the present application without giving measurement conditions, it means the melt index defined in ASTM D-1238, Condition 190 ° C / 2.16 kg (formerly known as "Condition (E)", and also known as l2). The merge index inversely proportional to the molecular weight of the polymer. In this way, the higher the molecular weight, the lower the melting index, although the relationship is not linear. The term "substantially linear" ethylene polymer or interpolymer, as used herein, means that, in addition to the short chain branches attributable to the incorporation of homogeneous comonomer in the interpolymers, the base structure of the polymer is substituted with a average of 0.01 to 3 branches of long chain / 1000 carbons, most preferably 0.01 long chain branches / 1000 carbons to 1 long chain branches / 1000 carbons, and especially 0.05 long chain branches / 1000 carbons to 1 long chain branches / 1000 carbons. In the present, the long chain branching is defined as a chain length of at least 1 carbon less than the number of carbons in the comonomer, while the short chain branching is defined herein, as a chain length of same number of carbons in the comonomer residue after it is incorporated into the base structure of the polymer molecule. For example, a substantially linear ethylene / 1-octene polymer has base structures with long chain branches of at least 7 carbons in length, but also has short chain branches of only 6 carbons in length. The long chain branching can be distinguished from the short chain branching using 13C nuclear magnetic resonance spectroscopy, and to a limited extent, for example, for ethylene homopolymers, can be quantified using Randall's method (Rev. Macromol. Chem. Phys. ., C29 (2 &; 3), p. 285-297). However, as a practical matter, 13C nuclear magnetic resonance spectroscopy can not determine the length of a long-chain branch with an excess of 6 carbon atoms and, as such, this analytical technique can not distinguish between a 7-branch. carbons and a branch of 70 carbons. The long chain branching may be as long as about the same length of the base structure of the polymer. As a practical matter, the current 13C nuclear magnetic resonance spectroscopy can not determine the length of a long chain branch with an excess of 6 carbon atoms. However, there are other known techniques useful for determining the presence of long chain branches in ethylene polymers, including ethylene / 1-octene interpolymers. Two such methods are gel penetration chromatography coupled with a low angle laser light diffusion detector (GPC-LALLS) and gel penetration chromatography coupled with a differential viscometer detector (GPC-DV). The use of these techniques for the detection of long chain branches and the underlying theories have been well documented in the literature. See, Zimm, G.H., and Stockmayer, W.H., J. Chem. Phvs., Vol. 17, p, 1301 (1949), and Rudin, A., Modern Methods of Polvmer Characterization, John Wiley & Sons, New York (1991), p. 103-112. A. Willem deGroot and P. Steve Chum, both of Dow Chemical Company, at the October 4, 1994 conference of the Federation of Analytical Chemistry and Spectroscopy Society (FACSS) in St. Louis, Missouri, USA, presented data demonstrating that GPC-DV is a useful technique for quantifying the presence of branching long chain in substantially linear ethylene interpolymers. In particular, deGroot and Chum found that the level of long-chain branches in substantially linear ethylene homopolymer samples, measured using the Zimm-Stockmayer equation, correlated very well with the level of long-chain branches 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 solution and, as such, can be represented for the molecular weight increase attributable to short chain octene branches knowing the molar percentage of the octene in the sample. Unrolling the contribution to the molecular weight increase attributable to the short-chain branches of 1-octene, deGroot and Chum showed that GPC-DV can be used to quantify the level of long chain branches in substantially linear ethylene / 1-octene copolymers . deGroot and Chum also showed that a Log plot (l2l Fusion index), such as a Log fusion (GPC, weight average molecular weight) as determined by GPC-DV, illustrates that the long chain branching aspects (but not the degree of branching) of substantially linear ethylene polymers, are comparable to those of highly branched low density polyethylene (LDPE) and are clearly distinct from ethylene polymers produced using Ziegler type catalysts, such as hafnium and vanadium complexes .

For ethylene / α-olefin interpolymers, the long chain branching is larger than the short chain branching resulting from the incorporation of the α-olefin (s) to the base structure of the polymer. The empirical effect of the presence of the long chain branching on ethylene / α-olefin interpolymers, substantially linear, used in the invention, manifests itself as improved rheological properties, which are quantified and expressed herein in terms of results of Gas extrusion rheometry (GER), and / or in terms of increase in the melt flow ratio (o / l2). In contrast to the term "substantially linear", the term "linear" means that the polymer lacks long chain branches that can be measured or can be demonstrated, that is, the polymer is replaced with an average of less than 0.01 long chain branches / 1000 carbons. The substantially linear ethylene interpolymers or homopolymers, as used herein, are further characterized in that they have: a) a melt flow ratio, 10 / l2 > 5.63, b) a molecular weight distribution or polydispersity, Mw / Mp, as determined by gel permeation chromatography, and defined by the equation: (Mw / Mn) _ £ (l? O / l2) -4.63, c) a critical shear stress at the beginning of the total melt fracture, as determined by gas extrusion rheometry, greater than 4 x 106 dynes / cm3, or a gas extrusion rheology, so that the critical shear rate at the start of the surface melt fracture, for the substantially linear ethylene polymer, is at least 50% greater than the critical shear rate at the beginning of the surface melt fracture for a linear ethylene polymer, wherein the polymer of substantially linear ethylene and the linear ethylene polymer comprise the same comonomer or comonomers, the linear ethylene polymer has a l2, Mw / Mn and a density within the % of the substantially linear ethylene polymer, and wherein the respective critical shear rates of the substantially linear ethylene polymer and the linear ethylene polymer, are measured at the same melting temperature using a gas extrusion rheometer, and d) a melting point of individual differential scanning calorimetry, DSC, between -30 ° C and 150 ° C. The determination of the critical shear rate and the critical shear stress with respect to the melt fracture, as well as other rheological properties such as the "rheological processing index" (Pl) was performed using a gas extrusion rheometer (GER) ). The gas extrusion rheometer is described by M. Shida, R.N. Shroff and L.V. Cancio at Polvmer Engineering Science, vol. 17, No. 11, p. 770 (1977), and in Rheometers for Molten Plastics by John Dealy, published by Van Nostrand Reinhold Co. (1982) p. 97-99. The processing index was measured at a temperature of 190 ° C, at a nitrogen pressure of 175.75 kg / cm2 gauge, using a diameter of 0.0117 cm, a die of 20: 1 L / D with an entry angle of 180 ° . The GER processing index was calculated in millipoise units from the following equation: Pl = 2.115x106 dynes / cm / (1000x shear rate), where: 2.5 x 106 dynes / cm2 is shear at 175.75 kg / cm2, and the shear rate is the wall shear velocity represented by the following equation: 32Q7 (60seg / min) (0.745) (diameter x 2.54cm / in) 3, where Q 'is the velocity of extrusion (g / min), 0.745 is the melting density of polyethylene (g / cm3), and the diameter is the diameter of the capillary hole (centimeters). Pl is the apparent viscosity of a material measured at an apparent shear stress of 2.15 x 106 dynes / cm2. For the substantially linear ethylene polymers described herein, the Pl is less than or equal to 70% of that of a comparative linear olefin polymer, having one l2 and Mw / Mn, each within 10% of the polymers ethylene substantially linear. The rheological behavior of the substantially linear ethylene polymers can also be characterized by the Dow Rheology Index (DRI), which expresses a "normalized polymer relaxation time as the result of long chain branching". (See, S. Lai and GW Kníght "ANTEC'93 Proceedings, INSITE ™ Technology Polyolefins (ITP) - New Rules in the Structure / Rheology Relation of Ethylene / a-Olefin Copolymers", New Orleans, Louisiana, USA, May ( 1993) DRI values range from 0, for polymers that do not have any measurable long chain branching (eg, Tafmer ™ products available from Mitsui Petrochemical Industries and Exact ™ products available from Exxon Chemical Company), to 15, and depends on the melt index.In general, for low-to-medium pressure ethylene polymers, (particularly at lower densities), DRI provides improved correlations for melt elasticity and high shear flow capacity with relationship to the correlations thereof with melt flow relationships For substantially linear ethylene polymers useful in this invention, DRI is preferably at least 0.1, and especially at least 0.5, and very especially at least 0.8. The DRI can be calculated from the following equation: PRI = (3652879 * t01 006 <;, 9 /? 0-1) / 10 where t0 is the characteristic relaxation time of the material and? 0 is the shear viscosity of the material. Both t0 and? 0 are the values of "best fixation" for the Cross equation, that is,? /? O = 1 / (1 +) and * to) n) where n is the exponential law index of the material Y ? ey are the viscosity and the shear rate (rad sec "1) measured, respectively. The determination of the viscosity baseline and the shear rate data are obtained using a Rheometric Mechanical Spectrometer (RMS-800) under a dynamic sweep mode of 0.1 to 100 rad / sec at 190 ° C and a Gas Extrusion Rheometer (GER) at extrusion pressures of 70.3 kg / cm2 at 3515 kg / cm2 (6.89 to 34.5 MPa), corresponding a shear stress of 0.086 to 0.43 MPa, using a die of 20: 1 L / D with a diameter of 0.0754 mm at 190 ° C. The determinations of the specific material can be made from 140 ° C to 190 ° C, as required for adapt to variations in melt index A graph of shear stress versus apparent shear rate is used to identify the phenomenon of fusion fracture According to Ramamurthy in Journal of Rheology, Vol. 30 (2), p. 337-357, 1986, above a certain veil As a critical flow condition, the observed irregularities of the extruded product can be broadly classified into two main types: surface melt fracture and total melt fracture. Surface fusion fracture occurs under seemingly stable conditions and flow scales in detail from the loss of specular brightness to the more severe form of "shark skin". In this description, the onset of the surface melt fracture (OSMF) is characterized as the onset of gloss loss of the extruded product, where the surface roughness of the extruded product can only be detected through a 40x magnification. The critical shear rate at the beginning of the surface melt fracture for substantially linear ethylene polymers is at least 50% greater than the critical shear rate at the beginning of the surface melt fracture of an ethylene polymer. linear that has approximately the same l2 and Mw / Mn. The total fusion fracture occurs at conditions and flow scales not stable in detail from regular deformations (alternating with rough and soft or helical) to random deformations. For commercial acceptance (for example, in blown film products), surface defects should be minimal, rather absent. The critical shear rate at the beginning of the surface melt fracture (OSMF) and at the beginning of the total melt fracture (OGMF) will be used in the present based on the changes in the roughness and surface configurations of the products. extruded through GER. The substantially linear ethylene polymers used in the invention are also characterized by an individual DSC melting peak. The individual melting peak is determined using a differential scaling calorimeter standardized with indium and deionized water. The method involves from 5 to 7 mg of sample sizes, a "first heating" at 150 ° C, which is maintained for 4 minutes, a cooling of 10 ° C / minute at 30 ° C, which is maintained for 3 minutes. m inutes and heated from 10 ° C / min uto to 150 ° C for the "second heating". The individual melting peak is taken from the heating curve of the "second heating" against the temperature. The total heat of the polymer melt is calculated from the area under the curve. For polymers having an intensity of 0.875 g / cm3 to 0.910 g / cm3, the individual melting peak may show, depending on the sensitivity of the equipment, a "shoulder" or a "ridge" on the low melting side that constitutes less than 12%, typically less than 9%, and very typically less than 6% of the total heat of fusion of the polymer. Such an artifact can be observed for other homogeneously branched polymers, such as EXACT resins (made by Exxon Chemical Company) and can be discerned based on the individual peak inclination that varies monotonically through the melting region of the artifact. This artifact occurs at 34 ° C, typically at 27 ° C, and more typically at 20 ° C, from the melting point of the individual peak. The heat of fusion attributable to an artifact can be determined separately through the specific integration of its associated area under the flow rate of heating to temperature. The term "polydispersity", as used herein, is a synonym for the term "molecular weight distribution", which is determined as follows. The polymer or composition samples are analyzed through gel penetration chromatography (GPC) in a high temperature chromatographic unit, 150 ° C, Waters, equipped with three columns of mixed porosity (Polymer Laboratories 103, 104, 10s, and 106), operating at a system temperature of 140 ° C. The solvent is 1, 2,4-trichlorobenzene, from which 0.3% by weight of solutions of the samples were prepared for injection. The flow rate is 1.0 milliliters / minute and the injection size is 200 microliters. The molecular weight determination is deduced using narrow molecular weight distribution polystyrene standards (from Polymer Laboratories) together with their elution volumes. The equivalent molecular weights of the polymer were determined using appropriate Mark-Houwink coefficients for polyethylene and polystyrene (as described by Williams and Word in Journal of Polvmer Science, Polvmer Letters, vol 6, page 621 (1968), to derive the following equation: Mpolietilßno = 3 * (M polystyrene) - In this equation, a = 0.4316, and b = 1.0 The weight average molecular weight, Mw, is calculated in the usual way according to the following formula: Mw =? ¡w , M, where w, and M, are the fraction by weight and molecular weight, respectively, of the ith fraction that is eluted from the GPC column Component A) in the composition of the present invention, also can be referred to as a "high density component" or briefly, "HD component"; component B) in the present composition can also be referred to as a "low density component", or briefly, "LD component". Component A), for use in the mixtures herein, may be any linear or substantially linear ethylene or interpolymer of ethylene interpolymer and one or more α-olefins having from 3 to 20 carbon atoms, preferably from 3 to 20 carbon atoms. 8 carbon atoms, having a density of 0.955 g / cm3 or greater, and a melt index of 0.3 to 10 g / 10 min, and a polydispersity of 1.8 to 10. When component A) has a density less than 0.955 g / cm3, this will result in poor stiffness and scratch resistance of the molded article. Preferably, component A) has a density of 0.960 g / cm 3 or greater, up to 0.970 g / cm 3. A melt index greater than 10 g / min results in poor mechanical properties, and a melt index below 0.3 g / 10 min can result in a melt fracture and rough surfaces during processing. Advantageously, component A) has a melt index of 0.5 to 3 g / 10 min. At polydispersity values exceeding 10, the gloss properties of the total composition are substantially reduced. Preferably, component A) has a polydispersity of 1.8 to 8. Polymers suitable for use as component A) are conventional ethylene homopolymers or high density ethylene copolymers containing up to about 0.5 mol% comonomer of a- olefin, but preferably ethylene homopolymers. This is typically prepared by polymerization in the presence of Ziegler or Phillips type catalysts, under particle forming polymerization conditions, such as mud or gas phase polymerizations, or under solution polymerization conditions. Preferably, the polymerization is presented in a single reactor to give the desired polydispersity. Typically, high density mud polyethylenes have polydispersities in the range of 5 to 10, and high density solution polyethylenes have polydispersities in the range of 3.5 to 5. Other suitable high density components A) for use in The present composition includes ethylene homopolymers or ethylene copolymers, preferably ethylene homopolymers, prepared through polymerization in the presence of transition metal compound catalysts containing cyclopentadienyl or cyclopentadienyl derivative portions. Examples of such catalysts include mono-, bis-, and tri-cyclopentadienyl transition metal compounds, mono (cyclopentadienyl) transition metal compounds, wherein the cyclopentadienyl ligand is p-linked to the transition metal and ligated to the transition metal. a linking group, said linking group is linked to the transition metal to provide a cyclic ligand structure, and the transition metal compounds bis (cyclopentadienyl), wherein the two cyclopentadienyl ligands can be linked together via a union group. These compounds typically require co-catalysts such as alumoxane (usually also referred to as aluminoxane) or ionic activators. These catalysts generally give polymers having polydispersities on the scale of 1.8 to 4. Preferably, component A) has a melt index ratio, 12% / L2, from 40 to 80, wherein L2 is the melt index measured at 190 ° C, under a load of 2.16 kg, and l21 is the melt index measured at 190 ° C, under a load of 21.6 kg. If the ratio of l2? / L2 is less than 40, the processability of the composition will be reduced, and the composition may be more susceptible to melt fracture during processing. If l2? / L2 is greater than 80, the brightness will be reduced. The low density component B) is generally an ethylene interpolymer having a density of 0.85 to 0.93 g / cm3, a melt index of 0.5 to 5 g / 10 min., and a polydispersity of 1.8 to 5. When component B) has a density greater than 0.93 g / cm3, the improvement in mechanical properties and the level of brightness will be lower, if any. Preferably, component B) has a density of 0.865 to 0.920 g / cm3, most preferably 0.865 to 0.915 / cm3, and especially less than or equal to 0.910 g / cm3. These preferred densities provide molded articles that exhibit a good combination of gloss, good impact resistance and good resistance to stress cracking. Advantageously, component B) has a melt index of 0.5 to 3 g / 10 min. This will provide good processing characteristics, brightness, impact resistance, and resistance to environmental stress cracking. At polydispersity values exceeding 5, the mechanical properties and gloss of the molded articles will be reduced. Preferably, component B) has a polydispersity of 1.8 to 4, most preferably 1.8 to 2.5. The polymers suitable for use as component B) are those of the linear and substantially linear ethylene interpolymer classes, which have the required density, melt index and polydispersity characteristics. Polymers suitable for use as the low density component B), in the compositions according to the invention, include linear interpolymers of ethylene and at least one additional α-olefin. The preferred α-olefins have from 3 to 20 carbon atoms. The highly preferred α-olefins have from 3 to 8 carbon atoms. Exemplary comonomers include propene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, and 1-octene. The low density component B) may also contain, in addition to the α-olefin, one or more additional comonomers, such as diolefins, ethylenically unsaturated carboxylic acids (both mono- and difunctional), as well as derivatives of these acids, such as esters and anhydrides. Examples of such additional comonomers are acrylic acid, methacrylic acid, vinyl acetate and maleic anhydride. Polymers suitable for use as component B), in the compositions herein, can be further characterized by their homogeneity and degree of long chain branching. The homogeneous interpolymers used in the present invention are defined herein as defined in the patent of US Pat. No. 3,645,992 (Elston). Accordingly, homogeneous interpolymers are those in which the comonomer is randomly distributed within a given interpolymer molecule, and wherein substantially all the interpolymer molecules have the same ethylene / comonomer ratio, within said interpolymer, while the heterogeneous interpolymers are those in which the interpolymer molecules do not have the same ethylene / comonomer ratio The term "narrow composition distribution", as used herein, describes the comonomer distribution for homogeneous interpolymers and means that the homogeneous interpolymers they have only a single melting peak and essentially lack a measurable "linear" polymer fraction. The homogenous interpolymers of narrow composition distribution can also be characterized by their SCBDI (Short Chain Branching Distribution Index) or by their CDBI (Composition Distribution Branch Index). The SCBDI or CDBI is defined as the weight percentage of the polymer molecules, having a comonomer content of 50% of the average total molar comonomer content. The CDBI of a polymer is easily calculated from the data obtained from the techniques known in the art, such as, for example, fractionation of elution of increase of temperature (abbreviated as "TREF") as described in, for example , Wild et al., Journal of Polymer Science, Polv. Phvs. Ed .. Vol. 20, p. 441 (1982), or in the patent of US Pat. No. 4,798,081. The SCBDI or CDBI for the homogeneous homogeneous interpolymers and copolymers of narrow composition, of the present invention, are generally greater than about 30%, preferably greater than about 50%, especially greater than about 90%. The homogeneous homogeneous interpolymers and copolymers of composition, used in the present invention, essentially lack a measurable (ie "linear" or "homopolymer") fraction of "high density", as measured by the TREF technique. . The homogeneous interpolymers have a degree of branching less than or equal to 2 methyl / 1000 carbons in about 15% (by weight) or less, preferably less than about 10% (in weight), and especially less than about 5% (in weight ). The term "broad composition distribution", as used herein, describes the comonomer distribution for heterogeneous interpolymers, and means that the heterogeneous interpolymers have a "linear" fraction and that heterogeneous interpolymers have multiple melting peaks (i.e. , exhibit at least two distinct melting peaks). Interpolymers and heterogeneous polymers have a degree of branching less than or equal to 2 methyl / 1000 carbons in about 10% (by weight) or more, preferably more than about 15% (in weight), and especially more than about 20 % (in weigh). The heterogeneous interpolymers also have a degree of branching equal to or greater than 25 methyl / 1000 carbons, in about 25% or less (by weight), preferably less than about 15% (by weight), and especially less than about 10% ( in weigh). A first subclass of linear olefin polymers, which have no long chain branching, is that of the heterogeneous, traditional, low density ethylene interpolymers (LLDPE) which are made using Ziegler catalysts in a gas phase process, of high pressure solution (for example, US Patent 4,076,698). These LLDPE polymers are referred to as heterogeneous LLDPEs. In the art, a distinction is usually made between LLDPE and very low density (VLDPE) or ultra low density (ULDPE) polymers. VLDPEs or ULDPEs are generally considered to be those polymers having a density less than about 0.915 g / cm 3. For the purposes of the present invention, said distinction will not be made for any of the heterogeneous or homogeneous polymers, but the term LLDPE will be used to cover the full scale of suitable densities for component B). The typical polydispersities for these heterogeneous polymers are from 3 to 5. very typically from 3.2 to 4.5. A further subclass of the linear olefin polymers is that of uniformly branched or homogeneous linear ethylene polymers (homogeneous LLDPE). The homogeneous polymers do not contain, like the heterogeneous LLDPE, any long chain branching and have only branches derived from the monomers having more than two carbon atoms. Homogeneous polymers include those made as described in the U.S.A. 3,645,992, and those made using the so-called individual site catalysts, and an intermittent reactor having relatively high olefin concentrations (as described in US Patents 5,026,798 and 5,055,438). The homogeneous LLDPE employed in the composition herein, generally has a polydispersity of 1.8 to 3, typically 1.8 to 2.5. A different class of polymers, suitable for use as component B) in the composition herein, is that of substantially linear ethylene polymers (SLEP). these polymers a thinning of shear and a processability facility similar to that of low density polyethylene, highly branched, polymerized free radical, (LDPE), but the strength and rigidity of LLDPE. Like traditional homogeneous polymers, the substantially linear ethylene / α-olefin interpolymers have only a single melting peak, as opposed to the linear, heterogeneous ethylene / α-olefin interpolymers, polymerized through Ziegler, traditional, which have two or more fusion peaks (determined using differential scanning calorimetry). The substantially linear olefin polymers and their methods of preparation are described in the U.S. Patents. 5,272,236 and 5,278,272. The polydispersity of the substantially linear olefin polymers is generally from 1.8 to 3, typically from 1.8 to 2.5. The substantially linear ethylene interpolymers can be made through gas phase, high pressure solution or mud phase polymerizations, but preferably through solution polymerizations. The low density components not suitable for use as component B) are the polymers produced through a high pressure polymerization process, using a free radical initiator resulting in the low density, branched long chain polyethylene, traditional (LDPE). The preferred low density components B) have densities in the range from 0.890 to 0.915 g / cm3, and advantageously from 0.890 to 0.910 g / cm3, and are substantially linear ethylene interpolymers, homogeneous and heterogeneous interpolymers of low ethylene. density, linear. Generally, the composition of the present invention comprises 95 to 60% by weight of component A), and 5 to 40% by weight of component B). Preferably, the composition comprises 95 to 80% by weight of A), and 5 to 20% by weight of B), based on the weight of A) and B). It has been found that at these preferred mixing ratios, a well balanced combination of gloss, mechanical properties, such as stiffness and strength, of the molded article is obtained. If a less rigid but more resistant composition having an improved surface gloss is desired, the compositions may contain more than 20% by weight of component B). The composition of the present invention can generally have a global density in the range of 0.94 to 0.962 g / cm 3, preferably a density of 0.95 to 0.96 g / cm 3. Especially preferred are the densities in the scale of 0.953 g / cm 3, and higher, in view of a high desired stiffness. The term "overall density" of the compositions herein, as used herein and in the claims, is based on the contributions of the polymeric components A) and B). The additives that can be included in the compositions herein can have an influence on the density of the composition, and are based on the amounts and nature of the additives, the overall density of the composition based on the polymer components can be easily determined. A) and B). In addition to an aesthetic function, the good gloss properties of the compositions herein also have a technical function. The brightness is the reflection of a smooth surface of the composition. An improved surface smoothness of a molded article provides a number of additional advantages, such as better surface printability, easier cleaning of the surface, and less friction when sliding against other surfaces. These additional advantages make the compositions herein also suitable for other end uses, where the aesthetic aspect is less important. The molding compositions of the present invention can be prepared by any known method suitable for mixing ethylene-based polymers. The components can be mixed in the solid state, for example, in powder or granular form, followed by the melting of one or both, preferably both, of the components. Suitable mixing devices include extruders, for example, single and double screw extruders, internal batch mixers such as Banbury mixers, Brabender mixers, Farrel continuous mixers and two roller mills. The order of mixing and the shape of the components in your mixture is not critical. The mixing temperatures are preferably such that an intimate mixture of the components is obtained. Typical temperatures are above the softening or melting points of at least one of the components, and most preferably above the softening or melting points of both components. It is also possible to mix the components in, or just before, the machine where the molding is presented, feeding the components separately to the molding machine. Typical melting mixing temperatures vary from 160 ° C to 250 ° C. The duration of the mixing is not critical, but good results are obtained when the mixing is from 30 seconds to 10 minutes. It is also possible to mix the dissolved or mud-like components in a medium, such as, for example, the polymerization medium, where they are prepared, followed by the removal of the medium and, optionally, by heating or mixing the resulting composition. The compositions of the present invention further comprise additives, such as, for example, fillers, antioxidants, processing aids, colorants, UV stabilizers, flame retardants, and gloss enhancing additives, such as mica. As processing aids, relatively less expensive processing aids, such as calcium and zinc stearates, can be used. The compositions of the present invention can be used to make molded articles, both single-ply and multi-ply articles, such as solid or hollow films, sheets, and rollers, through suitable known molding techniques. The term "molding" herein means any conversion technique that applies heat, pressure or a combination thereof to the composition herein, in order to obtain a shaped article. Examples include blow molding, blow molding by co-extrusion, blow molding by injection, injection molding, injection stretch blow molding, compression molding, extrusion such as profile extrusion, wires, cables, tubes, and sheets, and thermoforming. The compositions herein can be processed using blow molding conditions, which are typical for HDPE blow molding grades. Typical molding temperatures are in the range of 150 ° C to 250 ° C. The compositions herein can be blow molded using polished or unpolished dies, which give articles having good gloss properties. No special coating is required on the die, nor any of the expensive processing aids. The compositions herein can be used to prepare hollow articles, such as bottles, of good brightness and sufficient strength without requiring an additional layer of different polymer. When an additional layer is typically desired on the interior of the hollow article, conventional ethylene-based polymers may be used for said additional layer. The invention is further illustrated through the following examples, without limiting the invention thereto.

EXAMPLES In the examples, melt indexes will be expressed as l2 (measured in accordance with ASTM D-1238, condition E 190 ° C / 2.16 kg), 11 o (measured in accordance with ASTM D-1238, condition N 190 ° C / 10 kg) or l21 (measured in accordance with ASTM D-1238, condition F 190 ° C / 21.6 kg). The relation of the terms of fusion index, l 10 and that of l2, is the relation of fusion flow and is designated as o / l2. Tension properties such as ultimate tensile strength, elongation and modulus have been measured according to ASTM D-638-76, speed C (50 mm / min). The Izod impact properties have been measured in accordance with ASTM D-256. The "hood" properties of ESC R have been measured in accordance with ASTM 1963. The density properties have been measured in accordance with ASTM D-792-35. The viscosity at a shear rate of 100 sec '1 was determined using a Bohlin CS parallel fusion plate rheometer in oscillation mode (also known as frequency sweep). The measurement temperature is 190 ° C and the viscosity is expressed as the complex viscosity n * at an angular velocity of 10 rad / sec. The percentage of swelling was determined on an MCR capillary rheometer at an apparent shear rate of 300 sec '1, linked to an Instron Universal Test instrument and calculated according to the following formula: swelling percentage = (diameter of thread - diameter of die) / diameter of die * 100. The apparent viscosity at 10, 000 sec '1 was measured on a Goettfert 2003 capillary rheometer, using a die with a length: diameter ratio of 2.5: 0.5 mm. The gloss percentage of 45 ° was measured using Gardner Glossguard I I in accordance with ASTM D-2457. The brightness was measured on the outside of the bottle. The bottle was produced using a polished mold.

The compositions molded according to the invention preferably have a gloss value of 45 ° of at least 20%, most preferably at least 24%. The molding compositions, according to the present invention, preferably have an Izod impact of at least 200 J / m, preferably of at least 300 J / m, and most preferably of at least 500 J / m. Compositions according to the invention, preferably for gloss blow molding applications, provide a modulus stiffness of at least 600 MPa, most preferably at least about 750 MPa. This makes the compositions very suitable as bottles or blow molded containers. The polymers used in the experiments were: Component A) of high density High density polyethylene, HDPE 35060E, available from The Dow Chemical Company, having a density of 0.9605 g / cm2, l2 of 0.3 g / 10 min, l2i / l2 of 95, and a polydispersity of 12 (hereinafter HDPE 1); high density ethylene homopolymer having a density of 0.9656 g / cm3, l2 of 1.0, a l21 / l2 of 62, and a polydispersity of 6.7 (prepared using a Ziegler catalyst, in a single reactor sludge process) ( hereinafter HDPE 2); a high density, substantially linear ethylene homopolymer, having a density of 0.958 g / cm3, l2 of 1.7 g / 10 min, l10 / l2 of 12.1, and a polydispersity of 2.0, prepared by solution polymerization at 150 ° C using a bridged monocyclopentadienyl titanium catalyst, activated through an ionic activator (hereinafter HDPE 3); high density polyethylene, HDPE 35057E, from The Dow Chemical Company, having a density of 0.956 g / cm3, l2 of 0.29 g / 10 min, l2? / l2 of 95 and a polydispersity of 12 (hereafter HDPE 4 ).

Component B) of Low Density Polyolefin plastomer, AFFINITY ™ PL1880, which is a substantially linear ethylene / 1-octene copolymer, having a density of 0.902 g / cm3, l2 of 1.0g / 10 min, a polydispersity of 2.0 , a l? 0 / l2 of 9.52, a tension at the beginning of the fusion fracture (OSMF tension) of 4.3 x 10s Pa, at a shear rate of 1386 sec'1, and a tension at the beginning of the fracture by total melt (OGMF stress) of 4.7 x 105 Pa, at a shear rate of 2868 sec "1 (hereafter SLEP 1) (AFFINITY is a trademark of The Dow Chemical Company); polyolefin plastomer, AFFINITY FM 1570, which is a substantially linear ethylene / 1-octene copolymer, having a density of 0.915 g / cm3, l2 of 1.0 g / 10 min, a polydispersity of 2.0, a l10 / l2 of 10.2, an OSMF tension of 4.3 x 105 Pa, at a shear rate of 1522 sec -'1, and an OGMF tension of 4.7 x 105 Pa, at a shear rate of 2462 sec'1 (hereafter SLEP 2); polyolefin plastomer, AFFINITY FW 1650, which is a substantially linear ethylene / 1-octene copolymer, having a density of 0.902 g / cm3, l2 of 3.0 g / 10 min, a polydispersity of 2.0, a l10 / l2 of 8, an OSMF voltage of 3.9 x 10s Pa, at a shear rate of 2791 sec "1, and an OGMF voltage of 4.3 x 105 Pa, at a shear rate of 3720 sec" 1 (hereafter SLEP 3); polyolefin plastomer, AFFINITY XU 59206.00, which is a substantially linear ethylene / 1-octene copolymer, having a density of 0.902 g / cm3, l2 of 0.6 g / 10 min, a polydispersity of 2.0, a l10 / l2 of 12, an OSMF tension of 4.3 x 105 Pa, at a shear rate of 1303 sec "1, and an OGMF tension of 4.7 x 105 Pa, at a shear rate of 2059 sec" 1 (hereafter SLEP 4); substantially linear ethylene / 1-octene copolymer, having a density of 0.8998, 12 of 0.98 g / 10 min, a polydispersity of 2.0, and a l / 0 / l2 of 7.9 (hereinafter SLEP 5); substantially linear ethylene / 1-octene copolymer, having a density of 0.8988, 12 of 1.06 g / 10 min, a polydispersity of 2.0, and an o / l2 of 6.7 (hereinafter SLEP) 6); polyolefin elastomer, ENGAGE ™ LG8005, which is a substantially linear ethylene / 1-octene copolymer, having a density of 0.87 g / cm3, l2 of 1.0 g / 10 min, a polydispersity of 2.0, a l10 / l2 of 7.3, an OSMF voltage of 3.0 x 10s Pa, at a shear rate of 513 sec "1, and an OGMF voltage of 3.4 x 105 Pa, at a shear rate of 743 sec" 1 (hereafter SLEP 7) (ENGAGE is a trademark of The Dow Chemical Company); low density, linear, heterogeneous polyethylene, DOWLEX ™ NG5056E, which is a linear ethylene / 1-octene copolymer, having a density of 0.919 g / cm3, l2 of 1.1, and a polydispersity of 3.3 (hereinafter LLDPE 1) (DOWLEX is a trademark of The Dow Chemical Company); polyethylene with very low density, linear, heterogeneous, ATTANE ™ SL4100, which is a linear ethylene / 1-octene copolymer, having a density of 0.912 g / cm3, l2 of 1.0, and a polydispersity of 3.6 (hereinafter LLDPE 2) (ATTANE is a trademark from The Dow Chemical Company); linear, homogeneous ethylene / 1-butene copolymer, EXACT ™ 3028, which has a density of 0.9 and a l2 of 1.2 g / 10 min (hereinafter LLDPE 3) (EXACT is a trademark of Exxon Chemical Company); low density polyethylene, linear, heterogeneous, DOWLEX NG5055E, which is a linear ethylene / 1-octene copolymer, having a density of 0.923 g / cm3, l2 of 0.7, and a polydispersity of about 3.5 (hereinafter LLDPE 4); and low density polyethylene, LDPE 310, from The Dow Chemical Company, which is a free radical polymerized, branched ethylene polymer, having a density of 0.922 g / cm3, and a 1.2 of 1.2 (hereinafter forward LDPE). Components A) and B) (except LDPE 310), as used in the examples, contain from 400 to 1900 parts per million of oxidant or mixtures of oxidant, and from 1250 to 2350 parts per million of calcium stearate. The quantity and nature of the additives for EXACT 3028 are unknown. The evaluated compositions were prepared by feeding components A) and B) to a stirring mixer in the amounts indicated in Table I. 1000 ppm of each of pentaerythritil-tetrakis propionate (3,5-di-t-butyl-4-) hydroxyphenyl (IRGANOX ™ 1010) and tris (2,4-di-t-butylphenyl) phosphite (IRGAFOS ™ 168), and 1500 ppm calcium stearate were added as powder additives to the mixture (IRGANOX and IRGAFOS are trademarks of Ciba-Geigy). For the composition containing 67% HDPE 2 and 33% SLEP 4, 1000 ppm of IRGANOX 1010 and N, N'-bis (β-3,5-di-t-butyl-4) were added. -hydroxyphenyl-? ropiono) hydrazide (IRGANOX MD1024) The mixture was dry-mixed for 5 to 10 minutes at room temperature When only one component was evaluated, it was added to the extruder after being combined with the stabilizers. dry were transferred to a counter rotating twin screw extruder, Leistritz ZSE65, with a screw diameter of 6 7 mm and a length-to-diameter ratio of 24, and it was extruded to the temperature settings for the different zones of 180/190/200/200/200/200 ° C and at a screw speed of 40 rpm. The output speeds were approximately 28 kg / hr and the specific energies of approximately 0.16 kWh / kg. The oxygen level in the filling machine was 3%. 473 ml bottles (bottles of type ASTM 2561) were processed in a Fischer FBZ 1000 blow molding machine. The temperature profile was set at 175 ° C / 180 ° C / 190 ° C / 190 ° C / 190 ° C; the screw speed was 24 rpm. The weight of the bottles was 20 g and the line speed was 500 bottles / hour. The results are shown in Table I.

TABLE IA - COM PARATIVE COMPOSITIONS an average of two nm experiments not measured TABLE IB - COMPOSITIONS OF THE INVENTION CHART IC - COMPOSITION IS OF THE INVENTION T viscosity at 10,000 sec (Pax sec) Compositions according to the invention show improved brightness levels and properties superior to the impact, while still maintaining a good ESC R compared to the comparative compositions. The results for the comparative samples, in Table IA, show that the good values of brightness and an improvement (with respect to the component of pure H DPE used) in the properties to the impact, can not be achieved if simultaneously. Another advantage is the excellent blow molding ability of the compositions of the invention, as expressed, for example, by the swelling rate at a shear rate of 300 sec'1. The values for the viscosity at 100 sec "1 indicate excellent processability in other conversion operations.The lower the value the higher the production of the extruder.The lower apparent mechanical properties (compared with other compositions according to the invention). ) when using HDPE 3, it is believed that they are due to the lower density and the higher melt index, or the lower molecular weight of the HDPE component compared to HDPE 1 and 2. The experiments with HDPE 1 and HDPE 4 show , that at polydispersities too high (greater than 10) for the high density component, poor brightness values are obtained In a further experiment, a composition of 15% SLEP 1 and 85% HDPE 2, containing 250 ppm of Irganox 1010, 750 ppm of Irgafos 168, and 1000 ppm of calcium stearate, was compared with the composition of Table IB, first column, to study the effect of additive concentration on the brightness level.

TABLE II Table II shows that the effect of the additive level on the brightness value is of the same magnitude as that of the experimental variation within the measurement.

Claims (18)

1. - A molding composition comprising: A) from 95 to 60% by weight, based on the weight of A) and B), of an ethylene polymer having a density of 0.955 g / cm3 or greater, a melt index from 0.3 to 10 g / 10 min, and a polydispersity of 1.8 to 10, the ethylene polymer being, i) a high density ethylene homopolymer, or ii) a high density ethylene copolymer, prepared through polymerization of sludge or gas phase in the presence of a Ziegler or Phillips catalyst, or prepared by polymerization in the presence of a catalyst of a transition metal compound containing a cyclopentadienyl portion or cyclopentadienyl derivative; and B) from 5 to 40% by weight, based on the weight of A) and B), of a linear or substantially linear ethylene interpolymer, having a viscosity of 0.85 to 0.93 g / cm 3, a melt index of 0.5. at 5 g / 10 min, and a polydispersity of 1.8 to 5; wherein the composition has a density of 0.94 to 0.962 g / cm3.

2. The composition according to claim 1, wherein A) has a density of 0.960 g / cm3 or greater.

3. The composition according to claim 1 or claim 2, wherein A) has a melt index l2 of 0.5 to 3 g / 10 min.

4. The composition according to any of the preceding claims 1 to 3, wherein A) has a polydispersity of 1.8 to 8.

The composition according to any of the preceding claims 1 to 4, wherein A) has a melt index ratio, l2? / l2, from 40 to 80.

6. The composition according to any of the preceding claims 1 to 5, wherein B) has a density of 0.865 to 0.920 g / cm3.

7. The composition according to claim 6, wherein B) has a density of 0.865 or less than 0.910 g / cm3.

8. The composition according to any of the preceding claims 1 to 7, wherein B) has a melt index, 12, of 0.5 to 3 g / 10 min.

9. The composition according to any of the preceding claims 1 to 8, wherein B) has a polydispersity of 1.8 to 4.

10. The composition according to any of the preceding claims 1 to 9, wherein B) it is a substantially linear ethylene interpolymer.

11. The composition according to any of the preceding claims 1 to 10, comprising 95 to 80% by weight of A), and 5 to 20% by weight of B), based on the weight of A) and B).

12. The composition according to any of the preceding claims 1 to 11, wherein it has a density of 0.95 to 0.96 g / cm3.

13. - A process for preparing a molding composition comprising mixing: A) from 95 to 60% by weight, based on the weight of A) and B), of an ethylene polymer having a density of 0.955 g / cm3 or greater , a melt index of 0.3 to 10 g / 10 min, and a polydispersity of 1.8 to 10, the ethylene polymer being, i) a high density ethylene homopolymer, or ii) a high density ethylene copolymer, prepared through polymerization of slurry or gas phase in the presence of a Ziegler or Phillips catalyst, or prepared by polymerization in the presence of a catalyst of a transition metal compound containing a cyclopentadienyl portion or cyclopentadienyl derivative; and B) from 5 to 40% by weight, based on the weight of A) and B), of a linear or substantially linear ethylene interpolymer, having a viscosity of 0.85 to 0.93 g / cm 3, a melt index of 0.5. at 5 g / 10 min, and a polydispersity of 8.8 to 5; wherein the composition has a density of 0.94 to 0.962 g / cm3.

14. The process according to claim 13, wherein A) and B) are mixed under fusion.

15. A method for manufacturing molded articles, by molding a composition comprising: A) from 95 to 60% by weight, based on the weight of A) and B), of an ethylene polymer having a density of 0.955 g / cm3 or greater, a melt index of 0.3 to 10 g / 10 min, and a polydispersity of 1.8 to 10, the ethylene polymer being, i) a high density ethylene homopolymer, or ii) a copol high density ethylene number, prepared through sludge or gas phase polymerization in the presence of a Ziegler or Phillips catalyst, or prepared by polymerization in the presence of a catalyst of a transition metal compound containing a cyclopentadienyl moiety or cyclopentadienyl derivative; and B) from 5 to 40% by weight, based on the weight of A) and B), of a linear or substantially linear ethylene interpolymer, having a viscosity of 0.85 to 0.93 g / cm 3, a melt index of 0.5 to 5 g / 10 min, and a polydispersity of 8.8 to 5; wherein the composition has a density of 0.94 to 0.962 g / cm3.

16. - The method of claim 1, wherein the composition is blow molded.

17. A molded article obtained through the process of claim 15 or 16.

18. The molded article according to claim 17, in the form of a bottle, container, sheet or blown film.