MX2008006950A - Thermoplastic composition and articles having high impact strength and good appearance - Google Patents

Abstract

A thermoplastic molding composition suitable for making molded articles having high impact strength and good surface appearance is disclosed. The composition contains a blend of (co)polycarbonate, (co)polyester, and a grafted rubber. The structure of the grafted rubber includes a substrate and a grafted phase, and the substrate includes a core of crosslinked polymerized vinyl monomers and a shell, enveloping the core, the shell contains at least one crosslinked, polymerized acrylate which has a glass transition temperature less than 0°C.

Description

THERMOPLASTIC COMPOSITION AND ARTICLES THAT HAVE HIGH RESISTANCE TO IMPACT AND GOOD APPEARANCE FIELD OF THE INVENTION The invention relates to a thermoplastic molding composition and more specifically a composition containing (co) polycarbonate, (co) polyester and a modifier of impact resistance.

TECHNICAL BACKGROUND OF THE INVENTION Injection molded articles made of a composition containing polycarbonate and thermoplastic polyester (polyalkylene terephthalate) are often hardened by the inclusion of an impact resistance modifier such as an acrylonitrile-butadiene-styrene copolymer (ABS) or a copolymer of methyl methacrylate-butadiene-styrene (MBS). The exposure of such impact modifiers to visible and ultraviolet light causes their deterioration and as a consequence the degradation of the mechanical / physical properties and the discoloration of the composition in which they are included. While impact modifiers that are based on acrylate rubber are known to be more resistant to such effects, it has been noted for some time that articles molded from these compositions often show pronounced cosmetic defects close to the orifice area. of laundry, referred to as tiger stripes. These surface defects that appear as alternating bright bands perpendicular to the direction of flow are also referred to as "flow marks", or "ice lines".

US Patent No. 4,148,842 discloses an impact resistant combination containing polycarbonate resin and an interpolymer modifier comprising a crosslinked (meth) acrylate, cross-linked styrene-acrylonitrile (SAN) and non-crosslinked SAN components. Compositions containing polycarbonate and acrylate-styrene-acrylonitrile (ASA) graft polymers and methods for their preparation were described in U.S. Patent Nos. 3,655,824 and 3,891,719. In Japanese Patent No. 50154349, flame retardant compositions containing PC and ASA are described. Also relevant is WO 02/36688 which discloses compositions having improved impact strength and reduced discoloration containing polycarbonate (PC), ASA and high molecular weight acrylic copolymers as a processing aid.

U.S. Patent No. 6,476,126 discloses a weather resistant molding composition having an improved surface appearance containing polycarbonate and a grafted rubber containing a core / shell structure. In particular, the grafted rubber secures a cross-linked rubber substrate containing a crosslinked core and an envelope containing at least one polymerized acrylate, to which a rigid phase is grafted. The compositions described in this way contain from 10 to 50 weight percent of a grafted rubber, the structure of which is relevant at present. The aforementioned improvement of the aesthetics of the surface was achieved with the sacrifice of impact resistance.

U.S. Patents Nos. 5,104,934 and 5,082,897 are distinguished by describing thermoplastic molding compositions containing polycarbonate, polyesters and ABS or ASA. These compositions are mentioned for showing increase in moldability, thermal resistance and impact resistance in thick sections.

SUMMARY OF THE INVENTION A thermoplastic molding composition suitable for making molded articles having a high impact resistance and good appearance of the surface is described. The composition contains a combination of (co) polycarbonate, (co) polyester, and a grafted rubber. The structure of the grafted rubber includes a substrate and a grafted phase, and the substrate includes a core of crosslinked polymerized vinyl monomers and a shell containing at least one polymerized, crosslinked acrylate having a glass transition temperature of less than 0 ° C. that envelops the nucleus.

DETAILED DESCRIPTION OF THE INVENTION The thermoplastic composition of the invention is suitable for the preparation of molded articles characterized by a high gloss, a high resistance to impacts and the absence of tiger stripes. The composition comprises (A) from 9.9 to 99.8, preferably 50 to 85% by weight of a (co) polycarbonate resin, (B) from 0.1 to 90, preferably 5 to 60% by weight of ( co) polyester and (C) from 0.1 to 30 preferably 2 to 15% by weight of grafted rubber, the percentages being relative to the total weight of A, B and C.

In a preferred embodiment the composition contains at least one dye. Suitable as component (A) are homopolycarbonates, copolycarbonates and polyestercarbonates (the term "polycarbonate" as used herein refers to any of these resins, each characterized in that its molecular structure includes at least one carbonate linkage) and mixtures thereof.

Polycarbonates are known and their structures and methods of preparation have been described, for example, in U.S. Patent Nos. 3,030,331; 3,169,121; 3,395,119; 3,729,447; 4,255,556; 4,260,731; 4,369,303, 4,714,746 and 6,306,507 all of which are incorporated by reference herein. The polycarbonates generally have a weight average molecular weight of 10,000 to 200,000, preferably 20,000 to 80,000 and their melt flow rate, by ASTM D-1238 at 300 ° C, under a 1.2 kg load, is about 1. at about 65 g / 10 min., preferably about 2 to 35 g / 10 min. They can be prepared, for example, by the known diphasic interface process from a carbonic acid derivative such as phosgene and dihydroxy compounds by polycondensation (see German Patent Publications Nos. 2,063,050, 2,063,052, 1,570. 703, 2,211,956, 2,211,957 and 2,248,817, French Patent 1,561,518, and H. Schnell's monograph, "Chemistry and Physics of Polycarbonates", Interscience Publishers, New York, New York, 1964, all incorporated in the present report as reference).

In the present context, suitable dihydric compounds for the preparation of the polycarbonates of the invention conform to structural formula (1) or (2). (1) (2) where denotes an alkylene group with 1 to 8 carbon atoms, an alkylidene group with 2 to 8 carbon atoms, a cycloalkylene group with 5 to 15 carbon atoms, a cycloalkylidene group with 5 to 15 carbon atoms, a carbonyl group, an oxygen atom, a sulfur atom, -SO- or -S02 or a radical that adjusts to e and g both indicate the number 0 to 1; Z denotes F, Cl, Br or C 1 -C 4 alkyl and if several Z radicals are substituents on an aryl radical, they can be identical or different from each other; d indicates an integer from 0 to 4; Y f indicates an integer from 0 to 3.

The dihydric compounds useful in the practice of the invention are hydroquinone, resorcinol, bis- (hydroxyphenyl) -alkanes, bis- (hydroxyphenyl) -ethers, bis- (hydroxyphenyl) -ketones, bis- (hydroxy-phenyl) -sulphoxides, bis - (hydroxyphenyl) -sulfides, bis- (hydroxyphenyl) -sulfones, ya, a-bis- (hydroxyphenyl) -diisopropylbenzenes, as well as their alkylated core compounds. These and additional suitable aromatic dihydroxy compounds are described, for example, in U.S. Patent Nos. 5,105,004; 5,126,428; 5,109,076; 5,104,723; 5,086,157; 3,028,356; 2,999,835; 3,148,172; 2,991,273; 3,271,367; and 2,999,846, all incorporated herein by reference.

Additional examples of suitable bisphenols are 2, 2-bis- (4-hydroxy-phenyl) -propane (bisphenol A), 2,4-bis- (4-hydroxyphenyl) -2-methyl-butane, l, l- bis- (4-hydroxyphenyl) -cyclohexane, a, a'-bis- (4-hydroxy-phenyl) -p-diisopropylbenzene, 2,2-bis- (3-methyl-4-hydroxyphenyl) -propane, 2, 2 -bis- (3-chloro-4-hydroxyphenyl) -propane, bis- (3,5-dimethyl-4-hydroxyphenyl) -methane, 2,2-bis- (3,5-dimethyl-4-hydroxyphenyl) -propane , bis- (3, 5-dimethyl-4-hydroxyphenyl) -sulfide, bis- (3, 5-dimethyl-4-hydroxy-phenyl) -sulfoxide, bis- (3,5-dimethyl-4-hydroxyphenyl) -sulfone , dihydroxy-benzophenone, 2,4-bis- (3, 5-dimethyl-4-hydroxyphenyl) -cyclohexane, a, a '-bis- (3,5-dimethyl-4-hydroxyphenyl) -p-diisopropyl-benzene and 4, 4 '-sulfonyl diphenol.

Examples of the particularly preferred aromatic bisphenols are 2,2-bis- (4-hydroxyphenyl) -propane, 2,2-bis- (3,5-dimethyl-4-hydroxyphenyl) -propane, 1,1-bis- ( 4-hydroxyphenyl) -cyclohexane and 1,1-bis- (4-hydroxy-phenyl) -3,3,5-trimethylcyclohexane.

The most preferred bisphenol is 2,2-bis- (4-hydroxyphenyl) -propane (bisphenol A).

The polycarbonates of the invention can link to their structure units derived from one or more of the suitable bisphenols.

Resins suitable in the practice of the invention are polyester carbonates based on resorcinol and bisphenol A (registration number 265997-77-1), polycarbonates, copolycarbonates and terpolycarbonates with a phenolphthalein base such as those described in U.S. Pat. . 6,306,507, 3,036,036 and 4,210,741, all incorporated by reference herein.

The polycarbonates of the invention can also be branched by condensing small amounts, e.g. ex. from 0.05 to 2.0 mole% (with respect to the bisphenols) of polyhydroxy compounds.

Polycarbonates of this type have been described, for example, in German Patent Publications Nos. 1,570,533; 2,116,974 and 2,113,374; British Patents Nos. 885,442 and 1,079,821 and U.S. Patent No. 3,544,514. The following are some examples of polyhydroxy compounds which can be used for this purpose: fluoroglucinol; 4,6-dimethyl-2,4,6,6-tri- (4-hydroxy-phenyl) -heptane; 1, 3, 5- tri- (4-hydroxy-phenyl) -benzene; 1,1,1- tri- (4-hydroxyphenyl) -ethane; tri- (4-hydroxyphenyl) -phenylmethane; 2,2-bis- [4, 4- (4,4'-dihydroxy-diphenyl)] -cyclohexyl-propane; 2,4-bis- (4-hydroxy-l-isopropylidino) -phenol; 2, 6-bis- (2'-dihydroxy-5 '-methylbenzyl) -4-methyl-phenol; 2,4-dihydroxybenzoic acid; 2- (4-Hydroxyphenyl) -2- (2,4-dihydroxy-phenyl) -propane and 1,4-bis-. { 4, 4 '-dihydroxytriphenylmethyl) -benzene. Some of the other polyfunctional compounds are 2,4-dihydroxybenzoic acid, trimesic acid, cyanuric chloride and 3,3-bis- (4-hydroxyphenyl) -2-oxo-2,3-dihydroindole.

In addition to the above-mentioned polycondensation process, other processes for the preparation of the polycarbonates of the invention are polycondensation in a homogeneous phase and transesterification. Suitable procedures are described in United States Patents Núms. 3,028,365; 2,999,846; 3,153,008; and 2,991,273 incorporated herein by reference.

The process for the preparation of preferred polycarbonates is the interfacial polycondensation process. Other synthesis methods can be used in forming the polycarbonates of the invention, such as those described in U.S. Patent No. 3,912,688, incorporated herein by reference.

Suitable polycarbonate resins are available commercially, for example, Makrolon 2400, Makrolon 2458, Makrolon 2600, Makrolon 2800 and Makrolon 3100, all of which are homopolycarbonate resins with a bisphenol base that differ in terms of their respective molecular weights and characterized because their melt flow rates (MFR at 300 ° C, 1.2 Kg) per ASTM D-1238 are approximately 16.5 to 24, 13 to 16, 7.5 to 13.0 and 3.5 at 6.5 g / 10 min., respectively. These are products of Bayer MaterialScience LLC of Pittsburgh, Pennsylvania. The suitable polyester carbonate has a CAS number of 265997-77-1.

The term (co) polyester suitable as component (B), includes resins of homo-polyesters and co-polyesters, these are resins whose molecular structure includes at least one bond derived from a carboxylic acid, preferably excluding the carbon-acid-derived bonds. These are known resins and can be prepared through condensation or polymerization with ester exchange of the diol component with the diacid according to known methods. Examples are esters derived from the condensation of a cyclohexanedimethanol with an ethylene glycol with a terephthalic acid or with a combination of terephthalic acid and isophthalic acid. Polyesters derived from the condensation of a cyclohexanedimethanol with an ethylene glycol with an acid are also suitable., 4-Cyclohexanedicarboxylic acid. Suitable resins include poly (alkylene dicarboxylates), especially poly (ethylene terephthalate) (PET), poly (1,4-butylene terephthalate) (PBT), poly (trimethylene terephthalate) (PTT), poly (naphthalate ethylene) (PEN), poly (butylene naphthalate) (PBN), poly (cyclohexanedimethanol terephthalate) (PCT), poly (cyclohexanedimethanol-co-ethylene terephthalate) (PETG or PCTG), and poly (1,4-cyclohexanedimethyl-dicarboxylate 1,4-cyclohexane) (PCCD).

U.S. Patents Nos. 2,465,319, 3,953,394 and 3,047,539, all incorporated herein by reference, describe suitable methods for preparing such resins. Suitable polyalkylene terephthalates are characterized by an intrinsic viscosity of at least 0.2 and preferably of at least 0.4 deciliters / gram as measured by the relative viscosity of an 8% solution in orthochlorophenol at about 25 ° C. The upper limit is not critical but generally does not exceed approximately 2.5 deciliters / gram. Especially preferred polyalkylene terephthalates are those with an intrinsic viscosity in the range of 0.4 to 1.3 deciliters / gram.

The alkylene units of the polyalkylene terephthalates which are suitable for use in the present invention contain from 2 to 5, preferably from 2 to 4, carbon atoms. Polybutylene terephthalate (prepared from 1,4-butanediol) and polyethylene terephthalate are the preferred polyalkylene tetraftalates for use in the present invention. Other suitable polyalkylene terephthalates include polypropylene terephthalate, polyisobutylene terephthalate, polypentile terephthalate, polyisopentyl terephthalate, and polyneuropentyl terephthalate. The alkylene units may be straight chains or branched chains.

Component (C) indicates a grafted rubber comprising from 30 to 80 percent, preferably from 40 to 70 percent, based on its weight, of a rubber substrate containing (Cl) approximately 1 to 50%, with relative to the weight of the substrate, of a core containing at least one crosslinked vinyl polymer, and (C2) about 50 to 99%, based on the weight of the substrate of a shell containing at least one crosslinked acrylate (co) polymer having a vitreous transition temperature which is less than 0 ° C, preferably less than -20 ° C, to which the rubber substrate (C3) is grafted from 70 to 20 percent, preferably from 60 to 30 percent, with with respect to the weight of the grafted rubber, of a rigid grafted phase.

In a preferred embodiment, the composition is characterized in that the particle size (average weight particle size) of the grafted rubber is about 0.05 to 5 microns, preferably 0.1 to 2 microns.

The substrate contains from 1 to 50, preferably from 3 to 40, percent with respect to the weight of the substrate, from a core (Cl) and from 99 to 50, preferably from 97 to 60, percent with respect to the weight of the substrate of an envelope (C2) wherein (Cl) indicates a crosslinked polymerized product selected from at least one member of the group consisting of styrene, -methylstyrene, halogenated ring styrene, alkylated ring styrene, methyl methacrylate, acrylonitrile and the copolymer of either them with another one and the copolymer of any of them with acrylate and where (C2) indicates an envelope enveloping the core and comprising crosslinked rubber having a glass transition temperature of less than 0 ° C, preferably less than -20 ° C selected from the group consisting of C? -C? Alkyl alkyl acrylate , preferably C2-C8 alkyl acrylate, and C? -C? 8 alkyl acrylate copolymers, preferably C2-C8 alkyl acrylates with aromatic acrylates, said substrate being present in particulate form having a size (weight average particle size) ) from about 0.05 to 4, preferably from 0.1 to 1 microns.

The grafted phase (C3) contains a copolymer of at least one monomer selected from a first group consisting of styrene, α-methylstyrene, halogenated ring styrene and alkylated ring styrene, such as p-ethylstyrene and tert-butylstyrene with at least one a monomer selected from a second group consisting of(meth) acrylonitrile, methyl methacrylate and maleic anhydride. The weight ratio between said monomer or said monomers of said first group to said monomer or said monomers of said second group is from 90:10 to about 50:50. The grafted phase is preferably a styrene / acrylonitrile copolymer, a copolymer of α-methylstyrene / acrylonitrile or a terpolymer of α-methylstyrene / styrene / acrylonitrile. The copolymerization of styrene and / or α-methylstyrene with acrylonitrile can be carried out by radical polymerization, preferably, mass polymerization, solution polymerization, suspension polymerization or aqueous emulsion polymerization.

The component (C3) of the composition of the invention can be prepared by graft copolymerization of at least one of styrene, α-methylstyrene, halogenated ring styrene, alkylated ring styrene, such as p-methylstyrene and tert-butylstyrene with at least one of (meth) acrylonitrile, methyl methacrylate and maleic anhydride in the presence of the core-shell elastomeric substrate, crosslinked. Since a grafting yield of 100% can not be achieved in the graft copolymerization, the polymerization product of the graft copolymerization always contains a proportion of ungrafted, free copolymer.

The particle size according to the invention is the average particle size by weight as determined by an ultracentrifuge, for example according to the method of W. Scholtan and H. Lange, Kolloid-Z. und Z.-Polymere 250 (1972), 782-796. The ultracentrifuge measurement produces the integral mass distribution of the particle diameters of a sample. From this, it is possible to determine that the weight percentage of the particles has a diameter equal to or less than a certain size.

The grafted rubber (C) useful according to the invention can be prepared in the conventional manner by methods that are well known in the art. The core polymer (Cl) that is crosslinked can be prepared by conventional emulsion mechanisms that are well known in the art. Crosslinking can be achieved by incorporating small amounts, usually from about 0.05 to 10%, preferably 0.1 to 5%, based on the weight of the core, of any of the polyfunctional monomeric crosslinking agents, which are well known in the art. Examples include triallyl cyanurate, diallyl maleate and divinylbenzene.

The rubber sheath (C2) which may optionally contain units derived from C?-C6 alkyl methacrylate is characterized in that its vitreous transition temperature is lower than 0 ° C, preferably lower than -20 ° C.

The glass transition temperature of the acrylic acid ester polymer can be determined by the DSC method (K. H. Illers, Makromol, Chemie 127 (1969), page 1). Specific examples are n-butyl acrylate and acrylate 2-ethylhexyl. The acrylic acid esters can be used as individual compounds or in the form of mixtures of each other. In the preparation of the substrate, the esters of acrylic acid (or the other monomers constituting the shell) are polymerized in the presence of the core polymer (Cl) prepared previously.

In order to obtain the crosslinking of the preferred acrylic polymers, the polymerization is preferably carried out in the presence of 0.05 to 10% by weight, preferably 0.1 to 5% by weight, based on the total monomers used for the preparation of the graft bases, of a polyfunctional, preferably trifunctional, copolymerizable monomer that effects crosslinking and subsequent grafting. Suitable difunctional or polyfunctional crosslinking monomers are those containing two or more, preferably three, ethylenic double bonds that are susceptible to copolymerization and are not conjugated at 1,3 positions.

Examples of the suitable crosslinking monomers are divinylbenzene, diallyl maleate, diallyl fumarate and diallyl phthalate, and triallyl cyanurate and triallyl isocyanurate. Grafting agents, including unsaturated monomers having epoxy, hydroxy, carboxyl, and amino or acid anhydride groups, for example, may optionally be included. hydroxyalkyl (meth) acrylates.

The preparation of the grafted phase (C3) can be carried out according to the following method. First the rigid core (Cl) is prepared by polymerizing the vinyl monomer or monomers to form a crosslinked core in aqueous emulsion by conventional methods of 20 to 100 ° C, preferably 50 to 90 ° C. Conventional emulsifiers can be used, for example alkali metal salts of alkylsulfonic or alkylarylsulfonic acids, alkyl sulfates, fatty alcohol sulfonates, salts of higher fatty acids of 10 to 30 carbon atoms, or resin soaps. Sodium salts of alkylsulfonic acids or sodium salts of fatty acids of 10 to 18 carbon atoms are preferred. Advantageously, the emulsifier is used in an amount of 0 to 5% by weight, especially 0 to 2% by weight, based on the monomer or monomers used to prepare the core (Cl). In general, a water to monomer ratio of 50: 1 to 0.7: 1 is used. The polymerization initiators used are in particular conventional persulfates, e.g. ex. , potassium persulfate, but also redox systems can be used. In general, the initiator is used in an amount of 0.1 to 1% by weight, based on the monomer or monomers used in the preparation of the core (Cl). Additional polymerization additives which can be employed are conventional buffers, to bring the pH to about 6-9, for example, sodium bicarbonate and sodium pyrophosphate, and from 0 to 3% by weight of a molecular weight regulator, for example, a mercaptan, terpinol, or dimeric alpha-methylstyrene.

The precise polymerization conditions, such as the nature, the rate of addition, and the amount of emulsifier, initiator, and other additives, are selected, in the range referred to above so that the resulting latex of the cross-linked vinyl aromatic polymer achieves the indicated particle size.

The preparation of the cross-linked rubber wrap (C2) in the presence of the rigid core (Cl) to form the substrate according to the invention can be carried out by polymerizing the indicated monomers, for example, ester or esters of acrylic acid, and the cross-linking monomer / polyfunctional inter-graft, in aqueous emulsion by conventional methods of 20 to 100 ° C, preferably 50 to 80 ° C. Conventional emulsifiers can be used, for example alkali metal salts of alkylsulfonic acids or alkylarylsulfonic acids, alkyl sulfates, fatty alcohol sulfonates, salts of higher fatty acids of 10 to 30 carbon atoms, or resin soaps. Sodium salts of alkylsulfonic acids or sodium salts of fatty acids of 10 to 18 carbon atoms are preferred. Advantageously, the emulsifier is used in an amount of 0 to 5% by weight, especially 0 to 2% by weight, based on the monomer or monomers used to prepare the crosslinked envelope (C2). In general, a water to monomer ratio of 5: 1 to 0.7: 1 is used. The polymerization initiators used are in particular conventional persulfates, e.g. ex. , potassium persulfate, but also redox systems can be used. In general, the initiator is used in an amount of 0.1 to 1% by weight, based on the monomer or monomers used in the preparation of the cross-linked envelope (C2). Additional polymerization additives that can be employed are conventional buffers, to bring the pH to about 6-9, for example, sodium bicarbonate and sodium pyrophosphate, and from 0 to 3% by weight of a molecular weight regulator , for example, a mercaptan, terpinol, or dimeric alpha-methylstyrene.

The precise polymerization conditions, such as, the nature, the rate of addition, and the amount of the emulsifier, initiator, and other additives, are selected, in the range referred to above, so that the resulting latex of the substrate reaches the size of required particle according to the present invention.

To prepare the rigid grafted phase (C3), a monomeric system containing at least one monomer selected from a first group consisting of styrene, α-methylstyrene, alkylated ring styrene, such as, p-methylstyrene and tert-butylstyrene with minus one monomer selected from a second group consisting of (meth) acrylonitrile, methyl methacrylate and maleic anhydride is polymerized in the presence of the crosslinked rubber. The weight ratio between the monomer of said first group with respect to the monomer of said second group is from 90:10 to about 50:50.

It is advantageous if this graft copolymerization of the grafted phase on the crosslinked rubber substrate is carried out in aqueous emulsion according to known methods. The graft copolymerization can advantageously be carried out in the same system as the emulsion polymerization which is used to prepare the substrate, optionally with a new addition of emulsifier and initiator. The monomeric system to be grafted onto the base can be added to the reaction mixture once, in several stages or, preferably, continuously during the polymerization. Since the grafting yield of the graft copolymerization is not 100%, it is necessary to employ a somewhat larger amount of the monomer mixture for the graft copolymerization than would correspond to the desired degree of grafting. The control of the graft yield of the graft copolymerization, and therefore the degree of grafting of the finished grafted rubber (C) is familiar to those skilled in the art and is effected, inter alia, by the rate of addition of the monomers and adding a molecular chain regulator (Chauvel and Daniel, ACS Polymer Preprints 15 (1974), 329 f.).

The mixing of the components for the preparation of the composition of the invention can be carried out conventionally by methods and using equipment that is well known in the art.

The composition may additionally contain one or more conventional functional additives such as fillers, other compatible plastics, antistatic agents, antioxidants, flame retardants, lubricants and UV stabilizers. Suitable fillers include talc, clay, nanoclay (the prefix "nano" as used herein refers to a particle size of less than about 100 nanometers), silica, nanosilica as well as reinforcing agents such as glass fibers. Suitable UV absorbers include hydroxybenzophenones, hydroxybenzotriazoles, hydroxybenzotriazines, cyanoacrylates, oxoanilides, and benzoxazinones as well as nano-sized inorganic substances such as titanium oxide, dinium oxide, and eme oxide. Suitable stabilizers include carbodumides, such as bis- (2,6-dusopropylphenyl) carbodumide and polycarbodumides; light stabilizers of amines with spherical impediment; phenols with spherical impediment (such as Irganox 1076 (CAS number 2082-79-3), Irganox 1010 (CAS number 6683-19-8); phosphites (such as Irgafos 168, CAS number 31570-04-4; Sandostab P-EPQ, CAS number 119345-01-6; Ultranox 626, number CAS 26741-53-7; Ultranox 641, CAS number 161717-32-4; Doverphos S-9228, CAS number 154862-43-8), tpfemlfosfma, and phosphorous acid. Suitable hydrolytic stabilizers include epoxides such as Joncril ADR-4368-F, Joncril ADR-4368-S, Joncril ADR-4368-L, cycloaliphatic epoxy ream ERL-4221 (CAS number 2386-87-0). Suitable flame retardants include phosphorus compounds such as t-butyl phosphate, triphenyl phosphate, tpcresyl phosphate, diphenyl-cresyl phosphate, diphenyloctyl phosphate, diphen-l-2-ethyl ester phosphate, tri- phosphate phosphate. (isopropylphenyl), dimethyl esters of methylphosphonic acid, diphenyl esters of methylphosphonic acid, diethyl esters of phenylphosphonic acid, tpphenylphosphine oxide, tricresyl phosphide oxide and halogenated compounds. Especially advantageous are compounds which comply with formula (V) where R, R, R and R independently from each other indicate Ci to C8 alkyl, or C5 to C6 cycloalkyl, C6 to C2o aryl or C7 to Ci2 aralkyl each optionally substituted with alkyl, preferably R1, R2, R3 and R independently from one another indicate alkyl C? -C4, n independently of one another indicate 0 or 1, preferably 1.

N is from 0.1 to 30, preferably from 0.5 to 10, especially from 0.7 to 5, independently of one another indicates 0, 1, 2, 3 or 4, preferably 0, 1 or 2, and R5 and R6 independently of one another indicate C1-C4 alkyl, preferably methyl, and Y represents CX-C7 alkylidene , Cx-C7 alkylene, C5-C12 cycloalkylene, C5-C12 cycloalkylidene, -0-, -S-, -SO-, S02 or -CO-.

Especially preferred are compounds that conform to formula (V) which are bisphenol A derivatives or their methyl substituted derivatives. Such stabilizing additives are known in the art and are described in standard reference works such as "Plastics Additives Handbook", 5- edition, edited by H. Zweifel, Hanser Publishers incorporated herein by reference. The additives can be used in effective amounts, preferably from 0.01 to a total of about 30% with respect to the total weight of the resinous components A, B and C. The molding composition of the invention is suitable for making useful articles by any of the thermoplastic processes, including injection molding, blow molding and extrusion.

The thermoplastic composition of the invention can be molded into useful articles. It adapts particularly well to outdoor applications where high gloss, good aesthetics, and high impact resistance are required. Such applications include, but are not limited to, automotive articles (eg, fins, mirror housings, door handles), as well as lawn and garden equipment (such as hoods for tractors), sporting goods, electronic equipment , office equipment, household items and packaging materials.

The following examples illustrate the invention. In the examples, the parts and percentages are by weight, unless otherwise indicated.

EXAMPLES The compositions within the scope of the invention were prepared and their properties were determined. These were compared with similar compositions that differed only in terms of the chemistry and structure of the grafted rubber included.

The components of composition used in the course of the experiments described below were: PC: homopolycarbonate resin with a bisphenol base -A Makrolon 2458, a product of Bayer MaterialScience LLC. Which has a melt flow rate of approximately 20 g / lOmin (at 300 ° C, 1.2 kg load) determined in accordance with ASTM D 1238 PET: Polyethylene terephthalate having an intrinsic viscosity of 0.94 GR1: indicates a grafted rubber that is outside the scope of the invention, Blendex 984 a Chemtura product whose structure involves butyl acrylate rubber and a grafted SAN phase, its rubber content is about 45 weight percent, average particle size is about 0.4 microns. The structure does not include the core corresponding to the Cl of the invention.

GR2: indicates a grafted rubber that is outside the scope of the invention, Royaltuf 960A a product of Chemtura whose structure involves butyl acrylate rubber and a grafted SAN phase, its rubber content is about 60 weight percent, average particle size is about 0.4 microns. The structure does not include the core corresponding to the Cl of the invention. indicates a grafted SAN rubber within the scope of the invention, its rubber content is about 57 weight percent as determined by DSC, the average particle size is about 0.3 microns. The weight ratio of styrene to acrylonitrile of this rubber modifier (determined by infrared spectroscopy) is about 27 μ, the glass transition temperature of its acrylate shell is -41 ° C as determined by DSC (a speed of heating of 20 ° C per min.) The compositions indicated as Examples 1-4 contained all 85 parts by weight (pep) of polycarbonate, pbw PET and the indicated quantity of the grafted rubber.

In addition, each composition contained 0.7 pbw of an absorbent of Conventional UV, 0.1 pbw of a conventional thermal stabilizer and 1 pbw of dyes, which are not critical in the context of the invention. However it was observed that tiger stripes are more pronounced in compositions containing black dyes.

In the preparation of the illustrated compositions, the components and additives were melt compounded in a twin-screw extruder ZSK 30 at a temperature profile of 120 to 255 ° C. The pellets obtained were dried in a forced air convection oven at 120 ° C for 4 to 6 hours. The Izod bars were injection molded (melting temperature of 265 to 285 ° C, mold temperature of about 75 ° C).

The absence or presence of "tiger stripes" was determined by inspecting 20.3 x 30.5 x 0.3 cm plates that were molded with a molding tool that had the flange gate on the edge of the long side of the mold.

The temperature of the melt was about 285 ° C and the mold temperature was about 75 ° C.

The charging time of the melt was approximately 3 to 3, 7 seconds.

The determination of Izod impact strength was carried out using 0.3 cm thick specimens. The measurements were at 23 ° C, in accordance with ASTM D-256.

The results of the determinations are shown in the table below. The indicated grafted rubbers, their contents (pep) and the properties of the compositions are described below: TABLE indicates the appearance with intense tiger stripes; G indicates a molded piece that does not show tiger stripes While the invention has been described in detail in the foregoing for illustrative purposes, it should be understood that such detail is solely for this purpose and that those skilled in the art can make variations therein without departing from the spirit and scope of the invention. except as may be limited by the claims.

Claims (1)

1. REI INDICATIONS comeren in a r c i-i r i ation in o v: er a i es j c o venao said del sustrai: HÍ (a menom; 99- '; with respect to the weight of at least ac ilato jonmer a location I saw less than 0 ° C, iciuvenc r:? siaa cop less prime nor 11 '1 t \ 1? r J r t? 1 t ) 'i ti / f? -i ( O t p i 1 j 1 í ^ ^ \ _ 1 r - 3í . eoc :? or roe .. ¡ae ae i : s a e r tpos .orí 1, where o i cho r ar e i i o. 'Thermo pía stic to aue position Is there a product that contains 20 products? ..i., s .L. e.i J o : 1a in no -'-, i cho a u c i: ios in monome ron d i e h o eco i P: .n L recruzaao a i;: empera u. r. ns i. c.i on vatro a snowflake. i ime r mere:? mer arupo that rorisi sce a n i.11 c naioaenaao: eno de menos iTionomero se. .do one that consisted net. a n n 3 d r i "05, re anoin moncme spectrum to ooiorioro o o drain ap e; x i n damente l, 1 < ? n RESÜMFN DK "I? DESCRIPTION