MXPA01008924A - Polypropylene and polyester blends containing a graft-modified polyolefin elastomer - Google Patents

Abstract

Disclosed are polymer blend compositions comprising polypropylene, a thermoplastic polyester, a graft-modified polyolefin elastomer, and optionally an impact modifier and methods of preparation of such compositions.

Description

MIXES OF POLYPROPYLENE AND POLY ESTER CONTENI IN DO U N ELASTOMERO OF POLIOLEFINA MODIFIED WITH GRAFT This invention relates to compositions containing a polypropylene, a thermoplastic polyester, a graft-modified polyolefin elastomer, and optionally an impact modifier and methods of preparing such compositions. This invention relates in particular to a mixed composition having improved processability and when molded, having an improved impact force. Polypropylene, especially highly isotactic polypropylene, has been used in many applications in the form of molded articles, film, sheets, etc. , but it is excellent in molding processing capacity, rigidity, moisture resistance, gasoline resistance, chemical resistance, has a low specific gravity and is not expensive. However, polypropylene is poor or inadequate in heat resistance, firmness, impact resistance and tear resistance. These deficiencies are obstacles to opening new applications for polypropylene. On the other hand, thermoplastic polyesters, such as polyethylene terephthalate are widely used as engineering thermoplastics in the fields of automotive parts, electrical components and electronic parts, because such polymers have high heat resistance, stiffness, strength, resistance to solvent and oil resistance. However, it would be desirable to further improve the processability, hardness, nick impact strength and chemical resistance of these plastics. In addition, polyesters have disadvantages because these plastics have higher specific gravity and are more expensive than polypropylenes. From this point of view, it would seem a useful approach to mix polypropylene and a thermoplastic polyester, in order to obtain a thermoplastic resin having the characteristics of both of these polymers. However, the physical mixing of these polymers has proved difficult in practice. Because polypropylene and thermoplastic polyesters are naturally incompatible, it has been proven that it is not possible to simply mix these polymers in the melt to form a suitable mixture. These immiscible plastics exhibit poor adhesion along the domain interfaces with resulting weakness in the solid resin, evidenced as a thick phase separation. The mechanical properties, in particular impact strength, tensile elongation and tensile strength of a molded product made of a blend of polypropylene and thermoplastic polyester often have lower values than those expected by averaging the physical properties of the polypropylene and the thermoplastic polyester. When molded by injection, the resulting products show extreme non-uniformity and unacceptable appearance due to the formation of flow marks and can not be used in practice in the manufacture of articles to be used as automotive parts, electrical components and electronic parts. . It is previously known in the art to use interfacial and / or impact modifiers to produce mixtures of immiscible polymers with a desirable balance of properties. Interfacial agents provide adhesion between the main polymer phases, improving stress transfer, and are necessary to reduce interfacial tension during processing, which can lead to a thick phase separation In this way, interfacial agents play an important role in determining the ultimate morphology of the mixture. The interfacial tension reduction and impact modification can be provided by a simple compound or by different compounds Methods for improving the impact force on individual polymers, such as polypropylene, include the use of impact modifiers having a low glass transition temperature (Tg)., to significantly increase the impact force of a thermoplastic, it is necessary to mix in an impact modifier that forms finely dispersed rubber particles within the polymer matrix. These rubber particles improve the dissipation of energy in the thermoplastic, time that simultaneously limit the growth of the cracks To achieve the required morphology for effective hardening, the impact modifier should be compatible with the thermoplastic to be hardened. One method to improve the impact properties in polypropylene is to use polyolefin elastomers (POEs). Polymers are compatible with polypropylene and have a low glass transition temperature of less than 25 ° C, preferably less than 0 ° C Examples of these types of polymers include copolymers of alpha-olefins, such as ethylene copolymers and propylene, ethylene and 1-butene, ethylene and 1-hexene or ethylene and 1-ketene, and terpolymers and ethylene, propylene and a diene comonomer, such as hexadiene or ethylidene norbornene. Normally, impact modifiers useful for improving the impact resistance of polymers having a similar structure are often less useful for modifying different polymers in structure. For example, polyolefin elastomers are useful for improving the impact resistance of polypropylene, but are less useful for improving the impact resistance of thermoplastic polyester. However, it is well known that grafting functional groups to polymers can intensify their interaction with different polymers, this is sometimes referred to as compatibilization. These interactions may include chemical binding, for example, crosslinking, hydrogen bonding and dipole-dipole interaction. Normally, in order to obtain an advantageous degree of functional portions in the base polymer, a certain amount of residual unsaturation must be present. Maleic anhydride, for example, has been proposed as a compatibilizing group for a variety of plastic and polymer mixtures, see Plastics Technology, February 1 989, pages 67-75.; Albee et al, Plastics Compounding, September / October 1 990, pages 32-41; Hughes et al. , US-A-5, 346, 963 issued September 13, 1994, substantially linear ethylene polymers grafted with maleic anhydride; Hughes et al. , US-A-5, 705, 565, issued January 6, 1998, to increase the impact strength of thermoplastic mixtures selected by the addition of a minor amount of substantially linear ethylene polymer grafted with maleic anhydride; Tekkanat et al. , US-A-5,280,066, issued January 1, 1994, to increase the impact resistance of polyolefin blends by the addition of a minor amount of a hydrogenated block copolymer grafted with styrene-butadiene maleic anhydride. (SBR); Fujita et al. , US-A-5, 444, 1 19, issued August 22, 1995, to increase the impact resistance of blends of polypropylene and polyester with a copolymer of polypropylene and polyester and a maleic anhydride grafted with polypropylene; and Henman et al. , US-A-4,054, 549, issued October 18, 1977, to improve the adhesion between the polypropylene and polyester with a mixture of at least one acid containing boron, phosphorus or sulfur and a polypropylene grafted with maleic anhydride. Although some properties, such as impact resistance, have undoubtedly been improved in the above mentioned reference mixtures, other bulk properties of the resulting mixture have suffered. The present invention solves this problem. Accordingly, the present invention is directed to a blend composition of polymers comprising (a) polypropylene, (b) a thermoplastic polyester, (c) a polyolefin elastomer grafted with an unsaturated organic compound containing, prior to grafting , at least one site of ethylenic unsaturation and at least one carbonyl group, preferably maleic anhydride, and optionally (d) an impact modifier. Said composition possesses a good balance of good processability, good thermal and physical properties, good resistance to solvent, and in particular, improved impact resistance.

In a further embodiment, the invention also involves a method for preparing the above polymer blend composition comprising combining (a) polypropylene, (b) a thermoplastic polyester, (c) a graft-modified polyolefin elastomer, and optionally (d) ) an impact modifier. Still in a further embodiment, the invention involves a method for molding a blend composition whereby (a) the polypropylene has been blended with at least (b) a thermoplastic polyester, (c) a graft-modified polyolefin elastomer, and optionally (d) an impact modifier, it is molded. The component (a) in the polymer blend compositions of this invention is a polypropylene. The polypropylene suitable for use in this invention is well known in the literature and can be prepared by known techniques. In general, polypropylene is the isotatic form of polypropylene homopolymer, although other forms of polypropylene (eg, diphtheriatic or attic) can also be used. Polypropylene impact copolymers (for example, those where a secondary copolymerization step is employed which reacts ethylene with propylene), however, may also be used in the polymer blend compositions described herein. A full discussion of several polypropylene polymers is contained in Modern Plastics Encyclopedia / 89, broadcast mid-October 988, volume 65, number 1 1, pp. 86-92. The molecular weight of the polypropylene for use in the present invention is conveniently indicated using a melt flow measurement, sometimes referred to as melt flow rate (MFR) or melt index (Ml), according to ASTM D 1 238, condition 230 ° C / 2, 1 6 kilograms (kg). The melt flow rate is inversely proportional to the molecular weight of the polymer. In this way, the higher the molecular weight, the lower the melt flow rate, although the relationship is not linear. The melt flow rate for the polypropylene useful herein is generally greater than 0. 1 grams / 10 minutes (g / 10 min), preferably greater than 0.5 g / 10, more preferably greater than 1 g / 10. m in, and even more preferably greater than 1 0 g / 1 0 min. Speed IO melt flow for the polypropylene useful herein is generally less than 100 g / 10 min, preferably less than 75 g / 10 min, more preferably less than 60 g / 10 mln and more preferably less than 50 g / 10 min Polypropylene is used in the mixture compositions of polymer of the present invention in sufficient quantities to provide the desired balance of processing capacity and impact resistance. In general, polypropylene is employed in amounts of at least 5 percent by weight, preferably at least 10 percent by weight, more preferably at least 20 percent by weight, or even more preferably at least 30 percent by weight and most preferably at least 30 percent by weight. minus 40 percent by weight, based on the weight of the polymer blend composition. In general, polypropylene is used in amounts less than or equal to 95 percent by weight, preferably less than or equal to 90 percent by weight, more preferably less than or equal to 70 percent by weight, even more preferably less than or equal to equal to 50 percent by weight, and most preferably less than or equal to 45 percent by weight based on the weight of the polymer blend composition. The thermoplastic polyesters, component (b), which can be used in this invention are known and commercially available, and can be made by a variety of methods. A complete discussion of several polyester polymers is contained in Encyclopedia of Polymer Science and Engineering, 1988, vol. 1-312, the section on thermoplastic polyesters found in pp. 21 7-256. Examples of such thermoplastic polyesters, which are suitable as (b) include poly (alkylene alkanedicarboxylate), a poly (alkylene phenylene dicarboxylate), a poly (phenyl-alkanedicarboxylate), or a poly (phenylene phenylene dicarboxylate) and are therefore suitable for use herein . Methods and materials useful for the production of thermoplastic polyesters are discussed in greater detail in Whinfield, US-A-2, 465, 319, Pengilly, US-A-3, 047, 539 and Russell, US-A-3, 756, 986. Aromatic thermoplastic polyesters, such as poly (alkylene phenylene dicarboxylates), which include polyethylene terephthalate, polypropylene terephthalate and polybutylene terephthalate, or mixtures or copolymers thereof, are particularly useful in this invention. These aromatic thermoplastic polyesters preferably have an intrinsic viscosity between 0.35 and 1.2, more preferably 0.35 and 1. 1, and are more easily processed than aromatic thermoplastic polyesters with higher intrinsic viscosities.

The thermoplastic polyester is employed in the polymer blend compositions of the present invention in amounts sufficient to provide the desired balance of processability and impact resistance. In general, the thermoplastic polyester is employed in amounts of at least 5 percent by weight, preferably at least 10 percent by weight, more preferably at least 20 percent by weight, even more preferably at least 30 percent by weight, and most preferably at least 40 percent by weight, based on the weight of the polymer blend composition. In general, the thermoplastic polyester is used in amounts less than or equal to 95 percent by weight, preferably less than or equal to 90 percent by weight, more preferably less than or equal to 70 percent by weight, even more preferably less than or equal to 50 percent by weight, and preferably less than or equal to 45 percent by weight, based on the weight of the polymer blend composition. The third component (c) in the polymer blend composition is a graft-modified polyolefin elastomer. Suitable polyolefin elastomers comprise one or more C2 to C20 alpha-olefins in polymerized form, having a glass transition temperat(Tg) less than 25 ° C, preferably less than 0 ° C. Tg is the temperator number of temperat in which a polymeric material exhibits an abrupt change in its physical properties, including, for example, mechanical force. Tg can be determined by differential scanning calorimetry. Examples of the types of polymers from which the present polyolefin elastomers are selected include copolymers of alpha-olefins, such as copolymers of ethylene and propylene, ethylene and 1-butene, ethylene and 1-hexene, or ethylene and -octene, and ethylene propylene terpolymers and a diene comonomer, such as hexadiene or ethylidene norbornene A preferred polyolefin elastomer for use herein is one or more substantially linear ethylene polymers or a linear ethylene polymer (S / LEP) Both substantially linear ethylene polymers and linear ethylene polymers are known. The substantially linear ethylene polymers and their method of preparation are fully described in US-A-5,272,236 and US-A-5, 278,272. Linear ethylene polymers and their Preparation method are fully described in US-A-3,645,992, US-A-4,937,299, US-A-4701 432, US-A-4,937,301, US-A-4,935,397, US-A-5, 055,438, EP-A- 129 368, EP-A-260,999, and WO 90/07526 As used herein, "a linear ethylene polymer" means a copolymer of ethylene and one or more alpha-olefin comonomers having a linear backbone (ie, no crosslinking), without long chain branching, a narrow molecular weight distribution and a narrow composition distribution. Also, as used herein, "a substantially linear ethylene polymer" means a copolymer of ethylene and one or more comonomers of alpha-olefin having a linear backbone, a specific and limited amount of long chain branching, a narrow molecular weight distribution and a narrow composition distribution Short chain branches in a linear copolymer arise from the pending alkyl group resulting from the polymerization of C3 to C20 alpha-olefin comonomers intentionally added. The narrow composition distribution is sometimes referred to as homogeneous short chain branching. The narrow composition distribution and the homogeneous short chain branching refer to the fact that the alpha-olefin comonomer is randomly distributed within a given copolymer of ethylene and an alpha-olfein comonomer and virtually all copolymer molecules they have the same proportion of ethylene to comonomer. The narrowness of the composition distribution is indicated by the value of the composition distribution branching index (CDBI) or sometimes referred to as the short chain branching distribution index. CDBI is defined as the weight percentage of the polymer molecules having a comonomer content within 50 percent of the average molar comonomer content. The CDBI is easily calculated, for example, by employing levigation fractionation that raises the temperature, as described by Wild in the Journal of Polymer Science, Polymer Physics Edition, volume 20, page 441 (1981), or US-A-4, 798.081. The CDBI for the substantially linear ethylene polymers and the linear ethylene polymers in the present invention is greater than 30 percent, preferably greater than 50 percent and more preferably greater than 90 percent. The long chain branches in substantially linear ethylene polymers are polymer ramifications other than short chain branches. Normally, the long chain branches are formed by in situ generation of an oligomeric alpha-olefin via ß-hydride removal in a growing polymer chain. The resulting species is a vinyl-terminated hydrocarbon of relatively high molecular weight, which upon polymerization, produces the large pendant alkyl group. The long chain branching can be further defined as hydrocarbon branches for a polymer backbone having a chain length greater than n minus 2 (n-2) carbons, where n is the number of carbon atoms of the alpha-olefin comonomer plus large intentionally added to the reactor. Preferred long chain branches in copolymers of ethylene and one or more alpha-olefin comonomers of C to C20 have at least from 20 carbons to more preferably the number of carbons in the polymer backbone. The long chain ramification can be distinguished using 1 3 C nuclear magnetic resonance spectroscopy alone, or with laser light scattering-gel permeation chromatography (GPC-LALS) or a similar analytical technique. The substantially linear ethylene polymers contain at least 0.01 long chain branches / 1000 carbons and preferably at least 0.05 long chain branches / 1000 carbons. In general, substantially linear ethylene polymers contain less than or equal to 3 long chain branches / 1000 carbons and, preferably, less than or equal to 1 long chain branch / 1000 carbons. Preferred substantially linear ethylene polymers are prepared by using metallocene-based catalysts, capable of rapidly polymerizing high molecular weight alpha-olefin copolymers under the process conditions. As used herein, copolymer means a polymer of two or more functionally added comonomers, for example, as may be prepared by polymerizing ethylene with at least one other C3 to C20 comonomer. The linear ethylene polymers can be prepared in a similar manner using metallocene or vanadium based catalyst under conditions that do not allow the polymerization of monomers other than those intentionally added to the reactor. Other basic characteristics of substantially linear ethylene polymers or linear ethylene polymers include a low residue content (ie, a low concentration therein of the catalyst used to prepare the polymer, unreacted comonomers and low molecular weight oligomers made during the course of polymerization), and a controlled molecular architecture, which provides good processability even when the molecular weight distribution is narrow relative to conventional olefin polymers. Preferably, substantially linear ethylene polymers or linear ethylene polymers comprise between 50 and 95 percent by weight of ethylene and from 5 to 50, and preferably from 10 to 25 percent by weight of at least one alpha-olefin comonomer . Comonomer content in substantially linear ethylene polymers or linear ethylene polymers is generally calculated based on the amount added to the reactor, and as can be measured using infrared spectroscopy in accordance with ASTM D 2238, Method B. normally, substantially linear ethylene polymers or linear ethylene polymers are copolymers of ethylene and one or more C3 to C20 alpha-olefins, preferably copolymers of ethylene and one or more alpha-olefin comonomers of C3 to C4. and more preferably, copolymers of ethylene and one or more comonomers selected from the group consisting of propylene, 1-butene, 1-hexene, 4-methyl-1-pentane and 1-ketene. Most preferably, the copolymers are copolymers of ethylene and 1-ketene. The density of these substantially linear ethylene polymers or linear ethylene polymers is equal to or greater than 0.850 grams per cubic centimeter (g / cm3) and preferably equal to or greater than 0.860 g / cm1. In general, the density of these substantially linear ethylene polymers or linear ethylene polymers are less than or equal to 935 g / cm3 and, preferably, less than or equal to 0.900 g / cm3. Sometimes, it is useful to compare the melt flow rate (l? 0 / l2) as determined according to the conditions of ASTM D 1 238 of 1 90 ° C / 10.0 kg (l 10) and 1 90 ° C / 2.16 kg (l2). I 10 / l2 for substantially linear ethylene polymers is greater than or equal to 5.63, preferably from 6.5 to 1.5, and most preferably from 7 to 1 0. The molecular weight distribution (Mw / Mn) for ethylene polymers substantially linear is the weight average molecular weight (Mw) d divided by the number average molecular weight (Mn). Mw and Mn are measured by gel permeation chromatography (GPC). For substantially linear ethylene polymers, the ratio of l? _ / l2 indicates the degree of long-chain branching, that is, the higher the proportion of l 1 0 / l2, the greater the long-chain branching in the polymer. In preferred linear substantially ethylene polymers, Mw / Mn is related to l 10 / l2 by the equation: Mw / Mn < [(110 21) -4.63], and is at least 1.5 and preferably at least 2.0. In general, Mw / Mn for substantially linear ethylene polymers is less than or equal to 3.5, more preferably less than or equal to 3.0. In a most preferred embodiment, the substantially linear ethylene polymers are also characterized by a single differential scanning calorimetry (DSC) fusion peak. The preferred l2 melt index for these substantially linear ethylene polymers or linear ethylene polymers is from 0.01 g / 1 0 min to 1 00 g / 1 0 min, and more preferably 0. 1 to 10 g / 10 min. The unsaturated organic compound suitable for graft modification of the polyolefin elastomer, before grafting, preferably contains at least one site of ethylenic unsaturation and at least one carbonyl group (-C = O). Representative of unsaturated organic compounds containing at least one carbonyl group are carboxylic acids, anhydrides, esters and their salts, both metallic and non-metallic. Preferably, the organic compound contains ethylenic unsaturation conjugated to a carbonyl group. Representative compounds include maieic, fumaric, acrylic, methacrylic, itaconic, crotonic, methyl crotonic and cinnamic acids and their derivatives of anhydrides, esters and salts, if any. Maleic anhydride is the preferred unsaturated organic compound that contains at least one site of ethylenic unsaturation and at least one carbonyl group.

The unsaturated organic compound is used in an amount such that, after grafting to the polyolefin elastomer, it constitutes by weight at least 0.01 percent, preferably at least 0.05 percent, more preferably at least 0.1 percent, based on the weight of the elastomer of grafted polyolefin. The maximum amount of unsaturated organic compound content may vary at convenience, but usually constitutes less than or equal to 20 percent by weight, preferably less than or equal to 15 percent, more preferably less than or equal to 10 percent, more preferably less than or equal to 5 percent, and most preferably less than or equal to 2 percent by weight, based on the weight of the grafted polyolefin elastomer. The unsaturated organic compound containing at least one carbonyl group can be grafted to the polyolefin elastomer by any known technique, such as those shown in US-A-3,26, 91 7 and US-A-5,114,950. For example, the polymer is introduced into a two-roll mixer and mixed at a temperature of 60 ° C. The unsaturated organic compound is then added together with a free radical initiator, such as, for example, benzoyl peroxide and the components are mixed at 30 ° C until the grafting is complete. Alternatively, the reaction temperature is higher, for example, 210 ° C to 300 ° C, and a free radical initiator is not used or used at a reduced concentration. An alternative and preferred method for grafting is shown in US-A-4,950,541, by using a double screw devolatilizing extruder as the mixing apparatus. The polyolefin elastomer and an unsaturated organic compound are mixed and reacted within the extruder at temperatures at which the reactants are melted and in the presence of a free radical initiator. Preferably, the unsaturated organic compound is injected into the zone maintained under pressure within the extruder. The amount of the graft-modified polyolefin elastomer required to effectively serve as a compatibilizer will, of course, vary with the proportion of the polypropylene and the thermoplastic polyester, the chemical and physical characteristics of the polyolefin elastomer, the unsaturated organic compound containing an carboxyl group (and the degree of grafting) and similar factors. Preferably, the grafted modified polyolefin elastomer is present in an amount of at least 0.1 percent by weight; preferably at least 0.5 percent by weight, more preferably at least 1.0 percent by weight, more preferably at least 2.0 percent by weight, and most preferably at least 5.0 percent by weight, based on the weight of the blend composition. polymers. In general, the graft modified polyolefin elastomer is present in an amount less than or equal to 50 percent by weight, preferably less than or equal to 40 percent by weight, more preferably less than or equal to 30 percent by weight, more preferably less than or equal to 20 percent by weight, and most preferably less than or equal to 1 5 percent by weight, based on the weight of the polymer blend composition. Optionally, the polymer blend composition comprises (d) an impact modifier. Preferred impact modifiers are rubber materials having Tg's less than 0 ° C, preferably less than -1 0 ° C, more preferably less than -20 ° C and most preferably less than -30 ° C. Suitable rubbers include the well-known homopolymers and copolymers of conjugated dienes, in particular butadiene; as well as other elastic polymers, such as acrylate rubbers, in particular homopolymers and copolymers of alkyl acrylates having from 4 to 6 carbons in the alkyl group; or polyolefin elastomers as discussed hereinabove, in particular copolymers of ethylene, propylene and optionally a non-conjugated diene. If the impact modifier component (d) is a polyolefin elastomer, it may be the same as, or different from, the polyolefin elastomer selected for graft modification as component (c). In addition, the mixtures of the above elastic polymers can be used if desired. A preferred rubber is a homopolymer of butadiene and copolymer thereof with up to 30 weight percent styrene. Such copolymers can be random or block copolymers, and they can also be hydrogenated to remove the residual unsaturation. Preferably, a copolymer of aromatic vinyl block and conjugated diene formed from styrene and butadiene, or styrene and isoprene is used. When the copolymer of styrene and buadiene is hydrogenated, it is frequently represented as copolymer of styrene and (ethylene and butylene) in the di-block form, or as copolymer of styrene and (ethylene and butylene) and styrene in the form of tri-block. When the copolymer of styrene and isoprene is hydrogenated, it is often represented as a copolymer of styrene and (ethylene and propylene) in the form of a di-block, or as a copolymer of styrene and (ethylene and propylene) and styrene in the tri-block form. The aromatic vinyl block and diene block copolymers as described above, are discussed in greater detail in Holden, US-A.3, 265, 766, Haefele, US-A-3,333,024, Wald, US-A-3, 595, 942 and Witsipepe, US-A-3, 651, 014 and many are commercially available as the various KRATON ™ elastomers from Shell Chemical Company. Preferably, the impact modifier is a homopolymer or grafted copolymer of butadiene, which is grafted with a polymer of styrene and methyl methacrylate. Some of the preferred rubber-containing materials of this type are the known M-core BS core / shell copolymers, which have Tg less than 0 ° C and a rubber content greater than 40 percent, usually greater than 50 percent. They are generally obtained by polymerizing with styrene and methyl methacrylate grafts and / or equivalent monomers, in the presence of a conjugated diene polymer rubber core, preferably a homo- or co-polymer butadiene. The graft monomers can be added to the reaction mixture simultaneously or in sequence, when added in sequence, layers, shells or wart-like appendages can form around the substrate or core latex. The monomers can be added in various proportions to one another. Other impact modifiers useful in the compositions of this invention are those generally based on a long chain hydrocarbon backbone, which can be prepared predominantly from various mono- or dialkenyl monomers and can be grafted with one or more monomers stretch. Representative examples of a few olefinic elastomers, which illustrate the variation in known substances, which would suffice for such purposes, are as follows: butyl rubber; chlorinated polyethylene rubber; chlorosulfonated polyethylene rubber; an olefin polymer or copolymer, such as ethylene / propylene copolymer copolymer, ethylene / styrene copolymer or ethylene / prolene / diene copolymer, which can be grafted with one or more styrene monomers; neoprene rubber; nitrile rubber; polybutadiene and polyisoprene. If used, the impact modifier is preferably present in an amount of at least 1 percent by weight, preferably at least 2 percent by weight, more preferably at least 5 percent by weight, more preferably at least 10 percent by weight. by weight and most preferably, at least 15 percent by weight, based on the weight of the polymer blend composition. In general, the impact modifier is present in an amount less than or equal to 50 percent by weight, preferably less than or equal to 40 percent by weight, more preferably less than or equal to 30 percent by weight, more preferably less that is equal to 25 percent by weight, and most preferably less than or equal to 20 percent by weight, based on the weight of the polymer blend composition. The claimed polymer blend compositions may also optionally contain a component (e), which is one or more additives which are commonly used in polymer blend compositions of this type. Preferred additives of this type include, but are not limited to, they are not limited to: fillers, reinforcements, ignition-resistant additives, stabilizers, dyes, antioxidants, unsightly, flow enhancers, mold release agents, nucleating agents, etc. Preferred examples of additives are fillers, such as, but not limited to, talc, clay, wollastonite, mica, glass or a mixture thereof. Additionally, ignition resistance additives, such as, but not limited to, halogenated hydrocarbons, halogenated carbonate oligomers, halogenated diglycidyl ethers, organophosphorous compounds, fluorinated olefins, antimony oxide and aromatic sulfur metal salts may be used., or a mixture thereof. In addition, compounds that stabilize the polymer blend compositions can be used against degradation caused by, but not limited to, heat, light and oxygen, or a mixture thereof. If used, such additives may be present in an amount of at least 0.01 percent by weight, preferably at least 0.1 percent by weight, more preferably at least 1 percent by weight, more preferably at least 2 percent by weight, and most preferably at least 5 percent by weight, based on the weight of the polymer blend composition. In general, the additive is present in an amount less than or equal to 25 percent by weight, preferably less than or equal to 20 percent by weight, more preferably less than or equal to 15 percent by weight, more preferably less than or equal to 1 2 percent by weight, and most preferably less than or equal to 10 percent by weight based on the weight of the polymer blend composition.

The preparation of the polymer blend compositions of this invention can be accomplished by any suitable mixing means known in the art, including dry blending the individual components and subsequently mixing with melt, either directly in the extruder used to make the mixture. finished article (for example, the automotive part) or pre-mix in a separate extruder (for example, a Banbury mixer). The dry blends of the compositions can be injection molded directly without melt pre-mixing. When softened or melted by the application of heat, the polymer blend compositions of this invention can be formed or omitted using conventional techniques, such as compression molding, injection molding, gas assisted injection molding, calendering, formed with vacuum, thermoforming, extrusion and / or blow molding, alone or in combination. The polymer blend compositions can also be formed, spun or drawn into films, fibers, multi-lamellated sheets or extruded sheets, or can form com ponents with one or more organic or inorganic substances, in any suitable machine. for such purpose. Some of the items manufactured include automotive fender bars, fences, pillars and interior finishes; in filaments such as yarns and fibers; in pipes and jacketing of cables and wires; and on decks and housing of electrical equipment; as well as other household and personal items, including, for example, freezer containers.

To illustrate the practice of this invention, examples of the preferred embodiments are set forth below. However, these examples do not in any way restrict the scope of this invention. The compositions of Examples 1 to 4 were prepared by mixing the components in a drum mixer, and then feeding the dry mixed formulation to a Werner and Pfleider extruder of 30 mm. The following were the conditions of compound formation in the Werner and Pfleider extruder: barrel temperature profile: 1 90, 240, 270, 270 and 270 ° C; RPM: 350; Twist: 33 percent. The extrudate is cooled in the form of filaments and crushed as pellets. The pellets are dried in an air-flow oven for 3 hours at 120 ° C, and then n is used to prepare test specimens on an Arbur 70-ton injection molding machine, having the following molding conditions: barrel of 258, 257, 254 and 254 ° C; the mold temperature was room temperature; injection pressure: 30x105 Pa; maintenance pressure: 25x1 05 Pa; retro-pressure: 0 Pa; screw speed: 3.1; injection speed: 3.1; injection time: 3 seconds: maintenance time: 19 seconds; and cooling time: 20 sec undos. The formulation content and properties of Examples 1 to 4 are given in Table 1 below in percentage by weight of the composition by weight of the total composition. In Table 1: PP is homopolymer isotactic polypropylene commercially available as H702-20 from Dow, having 20 Ml; PET is polyethylene terephthalate, which is commercially available as LIGHTER R C88 from I NCA, having an intrinsic viscosity of 0.77 deciliters per gram (dl / g), measured according to the analytical method of I NCA 1 / MA / 1 / 002 and a density of 1.39 g / cm3; MAH-gEPDM is maleic anhydride grafted to the ethylene propylene rubber with some diene monomer, which is commercially available as ROYALTUFFM R 465 from Uniroyal Chemical Company; MAH-g-SLEP is a substantially linear ethylene polymer commercially available as ENGAGEM R SM 8180 from DuPnt / Dow Elastomers, grafted with 1 weight percent maleic anhydride and having one Ml after grafting 0.56. The following tests were run in Examples 1 to 4 and the results of these tests are shown in Table 1: Impact resistance as measured by the Izod nick test (Izod), was determined in accordance with ASTM D 256-90-B at room temperature. The specimens were cut from rectangular DTUL bars and measured 3.18 millimeters (mm) thick and 50.8 mm long. The specimens were nicked with a TMI marker 22-05 to give a radius notch of 0.254 mm. A pendulum of 22 kilograms was used. Impact resistance was measured by instrumented impact (Dart impact) was determined in accordance with ASTM D 3763 using an instrumented impact tester from General Research Corp. Dynatup 8250 weighing 45.4 kg. The results of the test were determined at room temperature on a disk with a thickness of 64 mm by 3. 1 8 mm. The stress property test was done in accordance with ASTM D 638. Type 1 stress test specimens were conditioned at 23 ° C and 50 percent relative humidity 24 hours before the test.

The test was performed using a mechanical I NSTRON 1 125 tester. The test was performed at room temperature. The flexural properties were determined in accordance with ASTM D 790. The test was performed using a mechanical I NSTRON tester. Test specimens of flexural properties were conditioned to 23 ° C and 50 percent relative humidity 24 hours before the test. The test was performed at room temperature. The deviation temperature under load (DTUL) was determined on a Ceast HDT 300 Vicat machine in accordance with ASTM D 648-82, where test specimens were tempered and tested under applied pressures of 0.46 MPa and 1.82 MPa. MFR was determined according to ASTM D 1 238 in a Tinius Olsen plastometer, at conditions of 230 ° C and an applied load of 3.8 kg. Dynamic mechanical spectroscopy (DMS) was determined in a Rheometrix RMS 800 dynamic mechanical spectroscopy, using a specimen cut of 50.8 mm length of the DTUL specimen. The test was performed from -150 ° C to the melting point of the mixture in a step of 5 ° C per stage and a frequency of 1 Hertz (Hz). The solvent test was conducted on tension bars placed on a template and aligned horizontally when adjusting a micrometer. Once aligned, the micrometer is adjusted, so that the specimen is bent to a deviation that will produce a distention of 0.05 and 1.25 percent. The formula used to convert the deflection to distension is: d = le 1 00Lt where I is the length of the stretch between mounting locks, e is the desired strain, L is the length of the specimen, t is the thickness, and d is the deviation . The specimens are immersed in a mixture of 60/40 iso-octane / toluene for 3, 5 and 10 minutes. For each immersion time, the specimens were taken and observed for cracks, followed by a stress test. The elongation at the break was recorded to determine the hardness after exposure to solvent.

Table 1.

Claims (14)

1. CLAIMS 1 . A polymer blend composition, comprising: (a) a polypropylene in an amount of from 94.9 to 5 percent by weight, (b) a thermoplastic polyester in an amount of from 5 to 94.9 percent by weight, (c) an ethylene polymer substantially linear or grafted linear ethylene polymer with at least 0.01 weight percent maleic anhydride, in an amount from 0.1 to 50 weight percent, wherein the substantially linear ethylene polymer or linear ethylene polymer has: (i) a density less than 0.93 g / cm3, (ii) a molecular weight distribution, Mw / Mn, of less than 3.0, and (ni) a branching index of composition distribution of more than 50 percent, and (d) a modifier of impact in an amount from 0 to 50 percent by weight, wherein the weight percentage is based on the weight of the polymer blend composition, said polymer blend composition does not contain a compound containing an epoxy group.
2. 2. The polymer blend composition of claim 1, wherein the substantially linear ethylene polymer or linear ethylene polymer is a copolymer of ethylene with a C3 to C20 alpha-olefin.
3. 3. The polymer blend composition of claim 1, wherein the substantially linear ethylene polymer or linear ethylene polymer is a copolymer of ethylene with propylene, 1-butene, 1 -hexene or 1-ketene.
4. 4. The polymer blend composition of claim 1, wherein the substantially linear ethylene polymer or linear ethylene polymer is a copolymer of ethylene and 1-ketene.
5. 5. The polymer blend composition of claim 1, wherein the substantially linear ethylene polymer or linear ethylene polymer is a terpolymer of ethylene, propylene and non-conjugated diene.
6. 6. The polymer blend composition of claim 1, wherein the polypropylene is isotactic.
7. 7. The polymer blend composition of claim 1, wherein the polyester is polyethylene terephthalate.
8. 8. The polymer blend composition of claim 1 further comprises a filler.
9. 9. The polymer blend composition of claim 8, wherein the filler is talc, wollastonite, clay, mica, glass or a mixture of the same.
10. 10. The polymer blend composition of claim 8, wherein the filler is talc. eleven .
11. The polymer blend composition of claim 1, further comprising one or more ignition resistance additives selected from halogenated hydrocarbons, halogenated carbonate oligomers, halogenated diglycidyl ethers, organophosphorus compounds, fluorinated olefins, antimony oxide and metal salts of aromatic sulfur compounds.
12. 12. The polymer blend composition of claim 1, wherein the polypropylene is an isotactic polypropylene, the thermoplastic polyester is polyethylene terephthalate, and the substantially linear ethylene polymer or linear ethylene polymer is a copolymer of ethylene and 1-ketene. 3.
13. A method for preparing a polymer blend composition comprising the step of combining: (a) a polypropylene in an amount from about 94.9 to about 5 weight percent, (b) a thermoplastic polyester in an amount from about 5 to about 94.9 weight percent, (c) a substantially linear ethylene polymer or linear grafted ethylene polymer with at least 0.01 weight percent maleic anhydride, in an amount from 0.1 to 50 weight percent, wherein the polymer of substantially linear ethylene or linear ethylene polymer has: (i) a density of less than 0.93 g / cm3, (ii) a molecular weight distribution, Mw / Mn, of less than 3.0, and (iii) a branching index of composition distribution of more than 50 percent, and (d) an impact modifier in an amount of from 0 to 50 percent by weight, wherein the percentage by weight is based on the weight of the composition of polymer blend, said polymer blend composition does not contain a compound containing an epoxy group.
14. 14. The method according to claim 1, wherein the polypropylene is an isotactic polypropylene, the thermoplastic polyester is polyethylene terephthalate, the polyolefin elastomer is a substantially linear ethylene polymer, which is a copolymer of ethylene and a polyethylene. -octene, and the unsaturated organic compound is maleic anhydride. 5. The composition of claim 1, in the form of a molded or extruded article.