Polyamide-polyarylene sulfide blends

Abstract: Polymer blends comprise a crystalline polyphthalamide component having high heat deflection temperature when filled with glass fibers and a polyarylene sulfide compo­ nent.

Description: This invention relates to blends comprising certain polyamides and polyarylene sulfides. Commonly assigned U.S. 4,603,166, issued July 29, 1986, discloses polyphthalamide compositions which, when filled with glass fibers and molded, have heat deflection temperatures at 1.82 MPa (264 psi), determined according to ASTM D-648, above about 245°C (473°F). Included are compositions comprising recurring terephthalamide and adipamide or terephthalamide, isophthalamide and adipamide units and, preferably, wherein the mole ratio of dicarboxylic acid moieties provided by the terephthalamide, isophthalamide and adipamide units is about 65-90:25-0:35-5, respectively. As disclosed therein, such compositions, including particulate- and fiber-filled compositions, exhibit desirable thermal properties including deflection temperature, high tensile strength and flexural modulus and are useful in various applications including preparation of molded articles, fibers, and laminates. Commonly assigned U.S. 4,617,342, issued October 14, 1986, and commonly assigned, copending application Serial No. 142,469 filed January 8, 1988, and published European Patent Application No. 84300745.1 (Publication No. 0122688), published October 24, 1984, disclose polyphthalamides which, when filled with glass fibers, have heat deflection temperatures at 1.82 MPa (264 psi), determined according to ASTM D-648, above 240°C. Compositions according to U.S. 4,617,342 are prepared from dicarboxylic acid compounds comprising terephthalic acid and isophthalic acid compounds in a mole ratio of 80:20 to about 99:1 and diamines comprising hexamethylene diamine and trimethylhexamethylene diamine in a mole ratio of about 98:2 to about 60:40. Compositions taught in application Serial No. 142,469 are based on terephthalic acid and isophthalic acid compounds in a mole ratio of about 70:30 to about 99:1 and hexamethylene diamine. Such compositions have utility in various applications, the neat and fiber-filled compositions being particularly suited for molding applications. For certain end uses it would be desirable to modify certain properties of polyphthalamides such as those described above. In particular, it would be desirable to provide such polythalamide compositions with improved solvent resistance and resistance to thermal-oxidative degradation, sometimes also referred to as thermal endurance. Such improvements would lead not only to longer useful life of products in the environments to which they are exposed in existing end uses, but also utility in additional applications with more stringent requirements. Examples of specific applications for such polyphthalamides in which improvements in chemical resistance and thermal endurance would be beneficial include under the hood automotive parts and pump housings for chemical processes. In general, it is known that modification of polymer properties may be achieved in various ways. Modification of the molecular structure of a given composition through the use of additional monomers in polymerization can lead to desirable improvements in some properties. However, the same often are accompanied by loss of other desirable properties and use of additional monomers is not always practical due to process considerations. Addition of other materials to a polymeric composition may lead to property improvements without complicating a polymerization process; however the effects of additives often are unpredictable and, again, improvements in some properties often are achieved at the expense of other properties. For example, addition of high strength fibers such as glass or graphite fibers to polyamides is known to improve mechanical properites, such as tensile strength and flexural strengths and moduli, but these improvements are achieved at the expense of ductility. Blending a given polymer with one or more other polymers may give blends with a combination of properties intermediate those of the individual components; however, processing requirements often limit the number of candidates that can be blended with a given polymer in an attempt to attain desirable property modifications and properties of a blend may or may not reflect those of its components depending on compatibility of the components with each other, reactivity thereof under blending or processing conditions and other factors. Polyarylene sulfides are known, high temperature thermoplastics having use in molding applications. As reported in "Technical Information On Ryton® Polyphenylene Sulfide Resins And Compounds" published by Phillips Petroleum Company, Plastics Technical Center, commercial polyphenylene sulfides designated Ryton® polyphenylene sulfide exhibit excellent dimensional stability, inherent flame retardancy, thermal stability, chemical resistance, desirable electrical properties and ease of processing. It has been proposed to blend certain polyamides with polyarylene sulfides for various purposes to obtain blends having modified properties relative to those of the neat resin(s). Thus, U.S. 4,292,416, assigned to Phillips Petroleum Company, discloses blending of polyarylene sulfides with semicrystalline polyamides or copolyamides, such as nylon 6 and polyamides obtained by condensation of a dibasic acid such as adipic, sebacic or terephthalic acid and a diamine such as hexamethylene diamine or 1,12-dodecanediamine, to give blends having improved molding characteristics and reduced warpage of parts molded therefrom. The disclosed compositions contain about 0.01 to 10 weight percent polyarylene sulfide. According to the patentee, the polyarylene sulfide must have a higher melting point than that of the polyamide. Inclusion of conventional additives for polyarylene sulfides, such as lubricants, stabilizers, pigments, dyes, fillers and plasticizers, also is disclosed. The patentee speculates that the improved properties of the blends result from a nucleating effect on the polyamide component imparted by the polyarylene sulfide component whereby crystallinity of the polyamide increases and properties dependent on degree of crystallinity are enhanced. The patentee also discloses that nucleation of polyamides can be accomplished through use of other, higher melting polymers which, during cooling, solidify prior to the polyamides so as to provide sites for nucleation. U.S. 4,528,335, also assigned to Phillips Petroleum Company, discloses amorphous polyamides, i.e., those having less than about 20 percent crystallinity, blended with polyarylene sulfides melting at about 260 to about 400°C to provide blends of improved impact strength and reduced shrinkage and warpage. According to the patentee, such blends generally contain a weight ratio of amorphous polyamide to polyarylene sulfide of 0.1:100 to about 100:100 and can also contain fillers such as glass and carbon fibers. U.S. 4,528,346, assigned to Dianippon Ink and Chemicals, Inc., discloses blends of low viscosity, uncrosslinked polyarylene sulfides not suited for injection molding, an epoxy compound and, optionally, a thermoplastic resin having a viscosity of at least 1,000 poise. According to the patentee such blends exhibit improved melt stability relative to commercially available injection molding grade polyarylene sulfides. Included among the various thermoplastic resins disclosed to be suitable as the optional component are polyamides obtained by condensing dicarboxylic acids, such as oxalic, adipic, suberic, sebacic, terephthalic, isophthalic or 1,4-cyclohexyldicarboxylic acid, with a diamine, such as ethylene diamine, pentamethylene diamine, hexamethylene diamine, decamethylene diamine, 1,4-cyclohexyldiamine and meta -xylylene diamine. Inclusion of fibers and inorganic fillers in such blends also is disclosed. Published Japanese Patent Application No. 55-135160, naming Asahi Fiber Glass Co. Ltd. as applicant, discloses blends of polyphenylene sulfide with nylon, unsaturated polyester or polyphenylene oxide resins, such resins being used to increase fluidity of the polyphenylene sulfide without sacrifices in other properties. Blends with nylon 6 and nylon 66 are specifically disclosed as are blends that contain glass fibers. International Patent Application No. PCT/US82/01688 (International Publication No. WO 83/02121), naming Phillips Petroleum Company as applicant, discloses blending a small amount of polyacrylamide or polyamide with polyarylene sulfide melting from about 260 to about 400°C to obtain compositions less corrosive to metals than neat polyphenylene sulfide. Among the disclosed polyamides are nylon 4, nylon 6, nylon 66, nylon 9, nylon 10, nylon 11, nylon 12, nylon 610, nylon 6T (polyhexamethylene terephthalamide), poly( p -phenylene terephthalamide), poly( m -phenylene isophthalamide), poly(N-N-diphenyl- p -phenylene isophthalamide), and polyamides derived from bis( p -aminocyclohexyl)methane and a dicarboxylic acid such as dodecanedioic acid. In the examples, blends containing up to 1 weight percent polyamide are disclosed. International Patent Application No. PCT/NL85/00046 (International Publication No. WO 86/03212), naming Stamicarbon BV as applicant, discloses blends containing 5 to 50 weight percent polyarylene sulfide and 95 to 50 weight percent polytetramethylene adipamide. Use of mixtures of polytetramethylene adipamide with other polyamides in such blends also is disclosed as are blends containing fibers and particulate fillers. U.S. 3,354,129, 3,862,095 and 3,790,536, all assigned to Phillips Petroleum Company, disclose arylene sulfide polymers and processes for preparing them. These patents mention that such polymers can be blended with various materials including other polymers. While the patents and publications discussed above disclose various blends, they do not disclose blends of a polyphthalamide component and a polyarylene sulfide component, wherein the polyphthalamide component comprises at least two recurring units selected from the group consisting of terephthalamide units, isophthalamide units and adipamide units and, when filled with 33 weight percent glass fibers, has a heat deflection temperature at 1.82 MPa (264 psi), according to ASTM D-648, above about 240°C. Further, such patents and publications do not disclose or suggest that blends of such a polyphthalamide component and a polyarylene sulfide component would exhibit the properties achieved according to this invention. Such patents also fail to disclose or suggest presently preferred blends according to the invention comprising a polyphthalamide of fast or intermediate crystallization rate, as indicated by heat deflection temperature at 1.82 MPa (264 psi) according to ASTM D-648 above about 240°C when filled with 33 weight percent glass fibers, comprising recurring terephthalamide, isophthalamide and adipamide units wherein the mole ratio of dicarboxylic acid moieties provided by such units is, respectively, about 65-90:25-0:35-5, and a polyarylene sulfide component. Further, contrary to the teachings or express requirements of some of the patents that polyarylene sulfide melting point exceed polyamide melting point, the same is not required of the components of the invented blends, melting points of polyphthalamides suitable according to this invention exceeding those of the polyarylene sulfide component by at least about 15°C. It is an object of this invention to provide blends of a polyphthalamide component comprising at least two recurring units selected from the group consisting of terephthalamide units, isophthalamide units and adipamide units which, when filled with 33 weight percent glass fibers, has a heat deflection temperature at 1.82 MPa (264 psi), according to ASTM D-648, above about 240°C and a polyarylene sulfide component and filled compositions based thereon having utility in molding and other applications. A further object of the invention is to provide such blends in which properties such as water absorption, methanol resistance, thermal endurance or flame resistance are improved relative to those of the polyphthalamide component. Other objects of the invention will be apparent to persons skilled in the art from the following. It has now been found that the objects of this invention can be attained by providing blends comprising a polyphthalamide component comprising at least two recurring units selected from the group consisting of terephthalamide, isophthalamide and adipamide units which, when filled with 33 weight percent glass fibers, has a heat deflection temperature at 1.82 MPa (264 psi), according to ASTM D-648, above about 240°C and a polyarylene sulfide component. Advantageously, such blends exhibit desirable thermal degradation temperatures, methanol resistance, water absorption, limiting oxygen index, thermal endurance and mechanical properties. Filled compositions based on such blends exhibit additional desirable properties such as improved tensile and flexural strengths and high heat deflection temperatures. The blends normally exhibit two distinct melting points and glass transition temperatures, indicating substantial immiscibility of the polyphthalamide and polyarylene sulfide components. Properties of the blends generally fall between those of the components, as is often the case in blends of immiscible components; however, at low to moderate levels of polyarylene sulfide component, improvements in solvent resistance and thermal endurance relative to the polyphthalamide component are significant. In such blends, the polyarylene sulfide component is present as a dispersed phase in a matrix or continuous phase of the polyphthalamide component; it was not expected that the presence of such a discontinuous phase in the polyphthalamide matrix would yield the degree of improvement in retention of mechanical properties after thermal aging or immersion in solvents achieved according to the invention. According to the present invention there is provided a composition comprising a blend of:- 1-99 weight percent of a polyphthalamide comprising at least two recurring units selected from terephthalamide units, isophthalamide units and adipamide units and which, when filled with 33 weight percent glass fibres has a heat deflection temperature at 1.82 MPa (264 psi) according to ASTM D-648 of at least 240°C measured using a mold heated to above Tg but below Tcm of the polyphthalamide, and 99-1 weight percent of a polyarylene sulphide component having a melting point of 285°C or lower, wherein the polyphthalamide component has a melting point exceeding that of the polyarylene sulphide component by at least 15°C. The polyphthalamide component comprises at least two recurring units selected from the group consisting of terephthalamide units, represented by the formula A below, isophthalamide units, represented by the formula B below, and adipamide units, represented by the formula C below: in the ratio A:B:C of 40-99: 0-35: 0-60 wherein R, R₁ and R₂ are independently divalent hydrocarbyl radicals and, preferably, divalent aliphatic hydrocarbyl radicals of 2 to about 14 carbon atoms. Also provided are such blends containing particulate or fibrous material. In greater detail, the blends of this invention contain about 1 to about 99 weight percent polyphthalamide component and about 99 to about 1 weight percent polyarylene sulfide component, such weight percents being based on the total weight of polyphthalamide and polyarylene sulfide components. Preferably, polyphthalamide content is about 10 to about 90 weight percent and polyarylene sulfide content is about 90 to about 10 weight percent because at lower polyarylene sulfide contents little change in properties relative to those of the polyphthalamide component is seen. More preferably, polyphthalamide component content is about 70 to about 90 weight percent and polyarylene sulfide component content is about 10 to about 30 weight percent because desirable mechanical properties of the polyphthalamide component are retained in the blends with significant improvements in solvent resistance and thermal endurance. These blends also can contain fibrous or particulate materials such as glass, graphite, boron, ceramic and aramid fibers, glass beads, calcium carbonate, graphite powder, pumice and the like. Combinations of such materials also can be used. Filled blends according to the invention are particularly desirable because they combine the desirable blend properties with the high strength and other properties imparted by the fibers or particulates. Typically, amounts of such fibers or particulates range up to about 60 weight percent based on weight of the filled composition. Preferably, about 10 to about 50 weight percent of fibers or particulates is used to achieve desirable improvements in strength, modulus and heat deflection temperature without substantial sacrifices in processability of the filled composition. Glass fibers are especially preferred for molding applications. The polyphthalamide component of the invented blends comprises at least two recurring units selected from the group consisting of terephthalamide units, isophthalamide units and adipamide units as depicted in formulas A, B and C above and, when filled with 33 weight percent glass fibers, has a heat deflection temperature at 1.82 MPa (264 psi), according to ASTM D-648, of at least about 240°C. Such polyphthalamides can be characterized as having a fast or intermediate rate of crystallization. For purposes hereof, such polyphthalamides are characterized as fast crystallizing if heat deflection temperature at 1.82 MPa (264 psi) according to ASTM D-648 of the polyphthalamide composition filled with 33 weight percent glass fibers and molded using a mold heated above the glass transition temperature ("Tg") but below the melt crystallization temperature ("Tcm") of the polyphthalamide normally is at least about 240°C and heat deflection temperature at 455 kPa (66 psi) according to ASTM D-648 of the unfilled polyphthalamide molded using a so-heated mold normally is at least about 220°C. Intermediate crystallizing polyphthalamides, for purposes hereof, are characterized by heat deflection temperatures at 1.82 MPa (264 psi) according to ASTM D-648 normally of at least about 240°C when so-filled and molded and heat deflection temperatures at 455 kPa (66 psi) according to ASTM D-648 normally below about 220°C in the case of the so-molded, unfilled compositions. Polyphthalamides with heat deflection temperatures at 1.82 MPa (264 psi) according to ASTM D-648 normally below about 240°C when so-filled and injection molded are slow-crystallizing or amorphous polyamides and are not suitable according to this invention because blends thereof with polyarylene sulfides exhibit low heat deflection temperatures and have poor chemical resistance unless polyarylene sulfide content of the blends is very high. Further, the slow crystallizing polyphthalamides can undergo crystallization during use at elevated temperatures of articles fabricated therefrom, resulting in dimensional change and premature failure. While the polyphthalamide component of the invented blends is described herein in terms of heat deflection temperature of at least about 240°C when filled with 33 weight percent glass fibers, it will be understood that such heat deflection temperatures often are also achieved at different fiber levels, the 33 weight percent level being chosen as a convenient reference point. Glass fibers of the type commonly utilized to prepare glass fiber-filled polyamide compositions suitable for injection molding can be used in the determination of heat deflection temperature. Compounding of such glass fibers with the polyphthalamide is conducted so that substantially uniform dispersion of fibers in the polyphthalamide is achieved. It also will be understood that heat deflection temperatures of the 33 weight percent glass fiber-filled polyphthalamide component of the invented blends can vary with molding conditions, including mold temperature and, to a lesser extent, cycle time, barrel temperature and injection pressure. Accordingly, while the polyphthalamide component of the invented blends is defined in terms of a heat deflection temperature at 1.82 MPa (264 psi) according to ASTM D-648 in respect of the 33 weight percent glass fiber-filled resin, it will be understood that resins having the specified heat deflection temperatures under appropriate conditions are suitable according to this invention even though molding conditions may be varied to avoid attaining such heat deflection temperatures. As indicated above, heat deflection temperatures of at least about 240°C normally are attained using a mold heated to above Tg but below Tcm of the polyphthalamide for 33 weight percent glass fiber-filled compositions containing the polyphthalamides suitable according to this invention. Use of nucleants and annealing also can facilitate achieving the specified heat deflection temperatures. Suitable glass fibers, compounding and molding conditions are illustrated in the examples appearing hereinbelow. In the formulas A, B and C depicted hereinabove, R, R₁ and R₂ are divalent hydrocarbyl radicals which can be the same or different. Straight chain, branched and cyclic aliphatic radicals and aromatic radicals are suitable. Preferably, R, R₁ and R₂ comprise an aliphatic radical of about 4 to about 20 carbon atoms, e.g., tetramethylene, hexamethylene, trimethylhexamethylene, decamethylene, dodecamethylene, dicyclohexylmethane, because polyphthalamides containing the same exhibit desirable thermal properties and good melt processibility and raw materials for such polyphthalamides are readily available. Best results are achieved when R, R₁ and R₂ comprise hexamethylene or hexamethylene and trimethylhexamethylene, and especially when R, R₁ and R₂ consist of hexamethylene. A preferred polyphthalamide component of the invented blends comprises a semicrystalline polyphthalamide of fast or intermediate crystallization rate based on at least one aliphatic diamine and terephthalic acid, isophthalic acid and adipic acid or teraphthalic acid and adipic acid in which the mole ratio of the dicarboxylic acid moieties in units A, B and C, as depicted in the above formulas, is about 65-95:25-0:35-5, with about 65-75:25-15:10 being more preferred. Such polyphthalamides based on various aliphatic diamines and preparation thereof are disclosed in detail in commonly assigned U.S. Patent No. 4,603,166, issued July 29, 1986. Particularly preferred among such polyphthalamides are those wherein R, R₁ and R₂ in the above formulas comprise hexamethylene or hexamethylene and trimethylhexamethylene. Most preferably, each of R, R₁ and R₂ is hexamethylene and the mole ratio of dicarboxylic acid moieties in the A, B and C units is about 65:25:10. Such polyphthalamides have melting points of about 305 to about 315°C and generally have inherent viscosities of about 0.75 to about 1.4 dl/g, with about 1.0 to about 1.1 dl/g being preferred from the standpoint or melt stability and ease of processing. Heat deflection temperatures at 1.82 MPa (264 psi), according to ASTM D-648, of such polyphthalamides filled with 30-45 weight percent glass fibers and molded at about 120°C generally range from about 480-580°F (250-305°C) as disclosed in U.S. 4,603,166. Also disclosed in U.S. 4,603,166 and suitable as the polyphthalamide component of the invented blends are polyphthalamides of terephthalic acid, isophthalic acid and adipic acid compounds, in mole ratios of 65:35:0, 55:35:10, 60:30:10, 50:0:50 and 60:0:40, with hexamethylene diamine. As reported in the patent, the 65:35:0, 55:35:10 and 60:30:10 compositions filled with 30 weight percent glass fibers had heat deflection temperatures at 1.82 MPa (264 psi) of about 115-132°C when molded using molds heated at about 120°C. With respect to the 50:0:50 and 60:0:40 compositions, the patent reports heat deflection temperatures at 1.82 MPa (264 psi) of 181°F (83°C) and 203°F (94°C) when molded without fillers at unspecified mold temperature and heat deflection temperature at 1.82 MPa (264 psi) of 563°F (295°C) for the 60:0:40 composition filled with 30 weight percent glass fibers molded at unspecified mold temperature. Tg of such polyphthalamides ranges from about 75 to 90°C. When molded using molds heated at about 96°C, heat deflection temperatures at 1.82 MPa (264 psi) according to ASTM D-648 of such compositions filled with 33 weight percent glass fibers exceed about 240°C, ranging from about 270 to 295°C. Among the polyphthalamides disclosed in U.S. 4,603,166, those melting at about 300°C or greater are particularly suitable according to this invention. Generally, polyphthalamides based on terephthalic, isophthalic and adipic acids having mole ratios of the dicarboxylic acid moieties set forth above and aliphatic diamines of two to eight carbon atoms, i.e., polyphthalamides having recurring units corresponding to the above formulas wherein R, R₁ and R₂ are independently C₂₋₈ aliphatic radicals, melt above about 300°C. Specific examples of such diamines include tetramethylene diamine, pentamethylene diamine and hexamethylene diamine. Mixtures of aliphatic diamines of up to eight carbon atoms also can be employed as can mixtures of one or more such diamines with minor amounts of higher aliphatic diamines, e.g., those having nine to twelve carbon atoms. Generally, as terephthalamide content of such polyphthalamides increases, greater amounts of such higher aliphatic diamines and larger diamines can be used to obtain polyphthalamides that melt above about 300°C. Polyphthalamides having heat deflection temperatures at 1.82 MPa (264 psi), according to ASTM D-648, when filled with 33 weight percent glass fibers, comprising recurring units A, B and C, as depicted in the formulas above, wherein the mole ratio of the dicarboxylic acid moieties in such units is about 40-65: up to 15:20-60 also are suitable. A specific example of a polyphthalamide having such a composition, disclosed in Table 10 of published European Patent Application No. 84300744.4 (Publication No. 0121984), published October 17, 1984, is a polyphthalamide of terephthalic acid, isophthalic acid and adipic acid in a mole fraction of 55/15/30 with hexamethylene diamine. Heat deflection temperature of the unfilled composition at 264 psi and unspecified mold temperature is reported therein as 194°F (90°C); however, when molded at about 104°C, heat deflection temperature of the unfilled composition typically is about 225°C at 455 kPa (66 psi) and about 165°C at 1.82 MPa (264 psi) and heat deflection temperature at 264 psi of the 33 weight percent glass fiber-filled composition molded at about 104°C is about 290°C. Especially preferred among such polyphthalamides are those wherein the mole ratio of the dicarboxylic acid moieties in the A, B and C units is greater than 50 but less than 60: greater than 0 to less than 15: at least 25 but less than 50, and especially wherein R, R₁ and R₂ comprise hexamethylene or hexamethylene and trimethylhexamethylene. Such polyphthalamides exhibit heat deflection temperatures at 1.82 MPa (264 psi) according to ASTM D-648 well in excess of about 240°C when filled with 33 weight percent glass fibers and have glass transition temperatures less than 100°C such that molding of the filled compositions to achieve such heat deflection temperatures can be carried out using steam-heated molds as opposed to more costly hot oil-heated systems. Mechanical properties, including tensile and flexural strength and modulus, of such polyphthalamides, particularly when filled with fibers or particulates, especially about 10 to about 60 weight percent glass fibers, together with their melt processibility and low water absorption tendencies (e.g., in the case of the 33 weight percent glass fiber-filled polyphthalamides, water absorption generally is less than about four weight percent after immersion in boiling water for 120 hours) and good retention of mechanical properties when wet, make such polyphthalamide compositions particularly well suited as injection molding materials. Also suitable as the polyphthalamide component of the invented blends are polyphthalamides prepared from dicarboxylic acid compounds comprising terephthalic acid and isophthalic acid compounds in a mole ratio of 80:20 to about 99:1 and diamines comprising hexamethylene diamine and trimethylhexamethylene diamine in a mole ratio of about 98:2 to about 60:40. Such polyphthalamides, when filled with 33 weight percent glass fibers, have heat deflection temperatures at 1.82 MPa (264 psi) according to ASTM D-648 of at least about 240°C and are described in detail in commonly assigned U.S. Patent No. 4,617,342, issued October 14, 1986. Such polyphthalamides can offer advantages in terms of their extremely high heat deflection temperatures at 1.82 MPa (264 psi) when filled with glass fibers and low water absorption due to an absence of adipamide units; however, melting points of such polyphthalamides are quite high, making melt processing more difficult. Also suitable for use in the invented blends are polyphthalamides based on terephthalic acid and isophthalic acid compounds in a mole ratio of about 70-99:30-1 and hexamethylene diamine. These polyphthalamides, when filled with 33 weight percent glass fibers, have heat deflection temperatures at 1.82 MPa (264 psi) according to ASTM D-648 of at least about 240°C and are described in detail in commonly assigned, copending application Serial No. 142,469. Generally, polyphthalamide compositions comprising at least two recurring units selected from the group consisting of terephthalamide, isophthalamide and adipamide units which, when filled with 33 weight percent glass fibers, have heat deflection temperatures at 1.82 MPa (264 psi), according to ASTM D-648, of at least about 240°C are suitable polyphthalamide components of the invented blends. As can be seen from the preceding paragraphs, suitable polyphthalamides include compositions having mole ratios of dicarboxylic acid moieties in the units A, B and C in the above formulas within the broad ranges of 40-99:0-35:0-60. Heat deflection temperature is influenced by polyphthalamide composition; accordingly, in polyphthalamides suitable according to this invention, proportions of such of the terephthalamide, isophthalamide and adipamide units as are present and the radicals R, R₁ and R₂ as represented in formulas A, B and C above, are such that the polyphthalamides, when filled with 33 weight percent glass fibers, have heat deflection temperatures at 1.82 MPa (264 psi) according to ASTM D-648 of at least about 240°C. While precise relationships between composition and heat deflection temperature are not fully understood, a number of general principles provide guidance in providing polyphthalamides of suitable composition and properties for purposes hereof. Generally, melting temperature, rate of crystallization and level of crystallinity in copolyamides of terephthalic acid, isophthalic acid compounds and hexamethylene diamine increase with increasing terephthalamide to isophthalamide mole ratios, other things being equal. Heat deflection temperature at 1.82 MPa (264 psi) according to ASTM D-648 of such copolyamides, when filled with 33 weight percent glass fibers, also increases with increased terephthalamide to isophthalamide mole ratios. Similarly, increasing heat deflection temperatures of glass-filled compositions at increasing terephthalamide plus adipamide to isophthalamide mole ratios in their terpolyamides with hexamethylene diamine can be seen from the aforementioned, commonly assigned U.S. Patent No. 4,603,166. Yu et al., J. Poly. Sci. , 42 , 249 (1960) report that adipic acid and terephthalic acid are isomorphous in certain copolyamides, including those with hexamethylene diamine, such that replacement of terephthalic acid with adipic acid results in little change in melting point, although the authors acknowledge inability to prepare high terephthalic acid content copolyamides due to decomposition during the attempted preparations. Yu et al. also reports that crystallinity of polyamides decreases with increased branching of diamines used in preparation thereof, other things being equal. Without wishing to be bound by theory, it appears that in the case of poly(hexamethylene phthalamides) consisting of at least two recurring units selected from the group consisting of hexamethylene terephthalamide, hexamethylene isophthalamide and hexamethylene adipamide units, there is a certain proportion of isophthalamide units, i.e., dicarboxylic acid moieties in units B in the above formulas, at or below which the polyphthalamides exhibit sufficient crystallinity and sufficiently high rates of crystallization during molding using a mold heated to at least Tg but below the melt crystallization temperature of the polyphthalamide that heat deflection temperatures at 1.82 MPa (264 psi), according to ASTM D-648, of the 33 weight percent glass fiber-filled compositions are normally at least about 240°C. Above a somewhat greater proportion of hexamethylene isophthalamide units, crystallinity and rates of crystallization are so low that the so-determined heat deflection temperatures of the 33 weight percent glass fiber-filled compositions normally are less than about 240°C. Between these levels of isophthalamide units, the so-determined heat deflection temperatures of the 33 weight percent glass fiber-filled compositions are normally at least about 240°C provided that the remaining units of the composition include hexamethylene terephthalamide units and the mole ratio of hexamethylene terephthalamide units to hexamethylene isophthalamide units is high enough. More specifically, such poly(hexamethylene phthalamides) consisting of about 19 to about 35 mole percent hexamethylene isophthalamide units based on total amide units, i.e., wherein the dicarboxylic acid moieties in units corresponding to the formula B above are about 19 to about 35 mole percent of the total dicarboxylic acid moieties, when filled with 33 weight percent glass fibers and molded using a mold heated above Tg but below Tcm normally have heat deflection temperatures at 1.82 MPa (264 psi) according to ASTM D-648 of at least about 240°C when the mole percentage of hexamethylene terephthalamide units (i.e, dicarboxylic acid moieties in units corresponding to formula A above) is at least about four times the mole percent hexamethylene isophthalamide units minus 75 percent. At hexamethylene isophthalamide unit contents in the upper portion of the aforesaid range of about 19 to about 35 mole percent, use of nucleants, higher mold temperatures, annealing and other techniques for promoting crystallization can be employed to facilitate attainment of heat deflection temperatures at 1.82 MPa (264 psi) of at least about 240°C according to ASTM D-648 in respect of the 33 weight percent glass fiber-filled polyphthalamides. Below about 19 mole percent hexamethylene isophthalamide units, heat deflection temperatures at 1.82 MPa (264 psi) according to ASTM D-648 of the so-filled and so-molded compositions normally exceed about 240°C whether the remaining units are all hexamethylene terephthalamide units, all hexamethylene adipamide units or a combination of hexamethylene terephthalamide units and hexamethylene adipamide units in any proportion. Above about 35 mole percent hexamethylene isophthalamide units, the poly(hexamethylene phthalamides) normally are amorphous or so slow to crystallize that the requisite heat deflection temperature at 1.82 MPa (264 psi) according to ASTM D-648 normally is not attained even with the use of nucleating agents, annealing or high temperature molds. Thus, polyphthalamides comprising at least two recurring units selected from the group consisting of terephthalamide, isophthalamide and adipamide units which, when filled with 33 weight percent glass fibers, have heat deflection temperatures according to ASTM D-648 of at least about 240°C include poly(hexamethylene phthalamides) consisting of at least two recurring units selected from the group consisting of hexamethylene terephthalamide, hexamethylene isophthalamide and hexamethylene adipamide units wherein the mole percent of the dicarboxylic acid moieties in the hexamethylene isophthalamide units based on total dicarboxylic acid moieties is 0 to about 35 mole percent; provided that when the mole percent of dicarboxylic acid moieties in the hexamethylene isophthalamide units is about 19 to about 35 mole percent, the mole percentages of dicarboxylic acid moieties in the hexamethylene terephthalamide, hexamethylene adipamide and hexamethylene isophthalamide units based on total dicarboxylic acid moieties (referred to below as M T , M A and M I , respectively) satisfy the following formulas: (2) M T + M I + M A = 100% Other suitable polyphthalamide compositions, for example, those based on diamines other than or in addition to hexamethylene diamine or comprising, in addition to at least two recurring units selected from terephthalamide, isophthalamide and adipamide units, other dicarboxylic acid amide units, can be employed if desired, suitability of specific compositions being easily determined based on heat deflection temperatures at 1.82 MPa (264 psi) of the 33 weight percent glass-filled compositions according to ASTM D-648 using a mold heated to above Tg but below Tcm of the polyphthalamide. The polyphthalamide component of the invented blends can be prepared from the appropriate starting materials, e.g., dicarboxylic acids or their derivatives and diamines, in suitable proportions by any suitable means. As disclosed in U.S. Patent No. 4,603,166, one such preparation involves a salt preparation step, preferably conducted batchwise to achieve proper stoichiometry, wherein dicarboxylic acid compounds, diamine and solvent are added to a suitable reaction vessel in appropriate amounts and maintained under conditions effective to cause salt formation but avoid appreciable conversion of salts to oligomers. Water is a preferred solvent and temperature is preferably maintained below about 120°C to minimize conversion. Product of the salt preparation step can be introduced into a condensation section operated either batchwise or in continuous mode. In the condensation section substantial conversion of salts to polymer takes place. The condensation product then typically is introduced into a finishing section, such as a twin-screw extruder, to obtain further conversion and generally increase inherent viscosity from a level of about 0.1 to about 0.6 dl/g achieved in the condensation section up to about 0.8 dl/g or greater. The polymeric product can be recovered from the finishing section and, for example, pelletized or mixed with fillers, additives and the like. Commonly assigned U.S. 4,603,193 also is directed to preparation of such polyamides. Polyarylene sulfides suitable according to the invention are those having a melting point up to about 285°C and comprising in their molecules recurring arylene sulfide groups. Such materials and preparation thereof are disclosed in U.S. 3,354,129, issued November 21, 1967, U.S. 3,790,536, issued February 5, 1974, and U.S. 3,862,095, issued January 21, 1975. Generally, polyarylene sulfides can be prepared from polyhalo-substituted aromatic compounds, such as 1,4-dichlorobenzene, and a suitable sulfur containing compound such as sodium sulfide, sodium hydrosulfide or hydrogen sulfide, at elevated temperature in a polar, organic solvent. Preferably, the polyarylene sulfide comprises a polyphenylene sulfide. More preferably an injection moldable polyphenylene sulfide melting at about 260 to about 280°C is used. Specific examples of suitable polyphenylene sulfides suitable for injection molding include Ryton® P4 Polyphenylene Sulfide manufactured by Phillips Petroleum Company and Tophren T4 Polyphenylene Sulfide manufactured by Tophren Company, Ltd. Commercially available materials generally are available in powder or pellet form, either being suitable for the present invention. Commercially available fiber-filled grades of polyphenylene sulfides can be used to prepare fiber-filled blends according to this invention. The blends according to this invention can be prepared by any suitable means. Conveniently, polyphthalamide and polyarylene sulfide components in powder or pellet form are melt blended in desired amounts at temperatures effective to render the blend components molten without degradation thereof in a high shear mixer, e.g., a twin-screw extruder, to obtain a desirably uniform blend. In view of the immiscibility of the blend components, use of kneading blocks or other suitable mixing elements is preferred in order to achieve a high degree of dispersion of the components. To minimize degradation of the blend and its components, preferred temperatures when using a twin-screw mixer are equal to or up to about 20°C greater than the melting point of the highest melting component of the blends. Blending of the components in solid form, such as powder or pellets, prior to melt blending can be conducted to facilitate melt blending. Particulates and fibers can be incorporated into one or more of the blend components prior to blending them or into the blends by physical mixing with the blends in powder or pellet form and then extrusion compounding the result, by feeding the particulates or fibers to the molten blend in an extruder or other compounding apparatus or by other suitable methods. Blending of polyphthalamide and polyarylene sulfide components and incorporation of particulates or fillers can be accomplished in a single pass through an extruder or other suitable apparatus by mixing and blending the polymeric components in an upstream section of the equipment and then adding the fibers or fillers to the molten, blended components in a downstream portion of the equipment. The invented blends also can contain pigments, stabilizers, flame retardants, nucleating agents, lubricants, impact modifiers and other suitable additives to improve or modify blend properties. A preferred heat stabilizer package is a combination of potassium iodine and cupric acetate. Such blends are particularly useful as unfilled and filled injection molding compounds for production of molded objects such as electronic connectors, switch components, pump housings, valve components and under-the-hood automobile parts. Injection molding of such compositions generally is conducted using standard injection molding equipment. The invented blends can also be formed into fibers or films or used as matrix materials or binders for composite or laminated structures. The present invention is described further in connection with the following examples, it being understood that the same are for purposes of illustration. In the examples and tables, examples of blends according to the invention are designated by Arabic numerals, comparative examples are designed by Roman numerals, with blends according to those comparative examples being designated by capital letters. Neat resins used in the examples and comparative examples also are designated by capital letters. EXAMPLE 1 Polyphthalamide components A, B and C, were prepared from terephthalic acid, isophthalic acid, adipic acid and hexamethylene diamine in a mole ratio of about 65:25:10:100 as follows: To a large, stainless steel, stirred reactor having an oil jacket heating system were added quantities of a 70-80 wt. % solution of hexamethylene diamine in water, adipic acid, isophthalic acid and terephthalic acid. About one mole percent benzoic acid, based on total moles of diamine and diacids, was added as a capping agent. Temperature increased during addition of the acids to 70°C. 800 parts per million sodium hypophosphite catalyst then were added to the reactor after which it was sealed, purged with nitrogen, leaving a 553 kPa (5.64 kg/cm², 80 psig) nitrogen blanket in the reactor, and then heated to about 120°C and held at that temperature. A second such reactor was charged, purged and heated in like manner and the two reactors were used in parallel to provide continuous feed of salt solution to downstream processing by alternating between the two reactors. Contents of the salt reactors were pumped continuously to a jacketed, oil-heated, stirred tank and maintained under pressure of 1.24 MPa (12.7 kg/cm², 180 psig) therein using a microprocessor-controlled Research Control Valve. The reactor was heated to about 220°C. Residence time in the reactor under such conditions was about 15 minutes, resulting in decrease in water content from about 35 wt.% based on weight of the materials in the initial charge to about 15 wt.% based on weight of material exiting the stirred tank. Contents of the tank were pumped continuously to and through two jacketed, oil heated, stainless steel pipes of 0.95 cm inner diameter and lengths of 274 and 401 cm in series at a rate of about 8.2 kg/hour using a dual headed Bran-Lubbe piston pump. The first pipe was maintained at about 315 - 325°C and the second at about 325 - 335°C both under pressure of about 12.55 MPa (128 kg/cm², 1820 psi). Contents of the second heated pipe were passed continuously through the Research Control Valve to a jacketed tube of about 0.94 cm inner diameter and about 274 cm length, equipped with thermocouples to monitor temperatures in the tube and between the outer wall of the tube and inner wall of the jacket, under pressure of about 765 kPa (7.8 kg/cm², 110 psig) with 325 - 345°C heat exchange fluid circulating in the heating jacket. Flashing of volatiles in the feed to the tube occurred in an upstream portion thereof. Contents of the tube, comprising water vapor and molten polymer, were introduced onto the screws of a Werner and Pfleiderer Corporation ZSK-30, twin-screw extruder. Volatiles were allowed to escape through a rear vent in the extruder barrel. Polymer was conveyed between screw flights with the screws rotating at 100 rpm and the extruder barrel heated at 300 to 330°C. Polymer was extruded through a strand die of about 0.24 cm diameter, passed into a water bath and then chopped into pellets. Inherent viscosity of the resulting polyphthalamide, identified hereinbelow as A, was about 0.88 dl/g. Melting point was 312°C. Melt crystallization temperature was 270°C. Polyphthalamide B was prepared substantially as described above except that pressure in the tube was slightly higher and temperature of the heat exchange fluid circulated around the tube was about 300 - 345°C. Inherent viscosity was about 0.98 dl/g and melting point was 310°C. Melt crystallization temperature was 260°C. Polyphthalamide C was prepared substantially as described above except pressure in the two pipes in series was about 14.81 MPa (151 kg/cm², 2150 psig) and pressure in the tube was about 627 kPa (6.4 kg/cm², 90 psig). Inherent viscosity was about 0.87 dl/g and melting point was 304°C. Melt crystallization temperature was 264°C. While polyphthalamides A, B and C were of like composition and prepared similarly, mechanical properties of Polyphthalamide A were generally lower than those of Polyphthalamides B and C, as can be seen from Tables 1 and 4-6 below, for unknown reasons. Mechanical properties of Polyphthalamides B and C are more representative of those of the 65:25:10 hexamethylene terephthalamide, hexamethylene isophthalamide, hexamethylene adipamide polyphthalamides than those of Polyphthalamide A. EXAMPLE 2 A blend of ten parts by weight of a commercially available polyphenylene sulfide powder, identified as Ryton® P4 from Phillips Petroleum Company and having a melting point of 277°C, with ninety parts by weight of Polyphthalamide A from EXAMPLE 1 was prepared by physically mixing 150 grams of the polyphenylene sulfide and 1350 grams of the polyphthalamide in a sealed bucket and tumbling the bucket for about 3 minutes. The mixture was fed to a Werner & Pfleiderer Corporation ZSK-30 twin-screw extruder at a rate of about 75 grams/minute. Extruder operating conditions and barrel temperature profile were as follows: Zone Barrel Temperatures (°C) Setting Indicated 1 79 113 2 149 158 3 204 213 4 299 301 5 299 303 6 299 301 7 299 306 8 299 300 Melt Temperature: 293°C Screw Speed: 50 rpm Screw Torque: 20% Screw configuration in the extruder consisted of sections having relatively long pitch in zones 1 and 2, spike-like sections in zone 3, compression sections in zones 4 and 5 and sections of longer pitch in zones 6 and 7. Gas present in the polymer melt was allowed to escape from the extruder barrel through a vent port located in zone 7. The molten blend exited the extruder through a strand die having a circular, 0.24 cm diameter orifice. The extrudate was cooled and chopped into pellets as in EXAMPLE 1. Subsequently, the pellets were dried in a pumped vacuum oven at 110°C (230°F) and 47 Pa (0.35 mm Hg) for 24 hours and then injection molded into test bars using an Arburg Injection Molding Machine operated as follows: Mold Temperature Setting: 93°C Rear Zone Setting: 293°C Front Zone Setting: 304°C Nozzle Setting: 304°C Injection Pressure: 21-42 kg/cm² Holding Pressure: 18-28 kg/cm² Back Pressure: 3.5-7 kg/cm² Screw Speed: 160-180 rpm Injection Speed Setting: 5 Injection Time Setting: 10 seconds forward, 20 seconds hold Total Cycle Time: 44 seconds Physical properties of the test bars were determined according to the following methods: Tensile Properties (including Ultimate Tensile Strength ("UTS") and Elongation at Break): ASTM D-638 (Type I test bars tested at 5 cm/minute); Flexural Properties: ASTM D-790; Notched Izod Impact Strength: ASTM D-256; Tensile Impact Strength. ASTM D-1822 (type S test bars were tested); Heat Deflection Temperature: ("HDT") ASTM D-648; Water Absorption: ASTM D-570; Methanol Exposure ASTM D-543; Limiting Oxygen Index (LOI): ASTM D-2863; Glass Transition Temperature (Tg), Melting Temperature (Tm) and Melt Crystallization Temperature (Tcm): Pellets tested by Differential Scanning Calorimetry at 20°C/minute Degradation Temperature: Pellets tested by Thermal Gravimetric Analysis at a 10°C/minute scan rate, under nitrogen. Test results are reported in TABLE 1 below. In accordance with the ASTM test methods identified above, an average of results for the number of samples specified in the test methods is reported in TABLE 1 and subsequent tables. EXAMPLES 3-4 Following essentially the procedure of EXAMPLE 2, a series of compositions was prepared from the materials used in that example but with variations in levels of polyphenylene sulfide and polyphthalamide components. Samples of neat polyphthalamide A from EXAMPLE 1 and neat polyphenylene sulfide used in EXAMPLES 2-4 also were processed in the ZSK-30 twin-screw extruder essentially as in EXAMPLE 2 to provide comparable thermal history. Test bars were molded from the blends and neat resins according to the procedure of EXAMPLE 2 and tested as described therein. Properties and molding conditions are reported in TABLE 1. In the table the neat polyphenylene sulfide is designated "D". Example A 2 3 4 D Polyphthalamide/Polyphenylene Sulfide (wt.%) 100/0 90/10 50/50 10/90 0/100 UTS (kg/cm²) 754 609 124 321 461 Elongation at Break (%) 3.2 2.52 0.60 1.26 1.47 Flexural Strength (kg/cm²) >1556 1184 747 740 719 Flexural Modulus (x 10³ kg/cm²) 33.5 35.9 38.5 40.5 44.7 Notched Izod (cm-kg/cm) 3.3 3.1 1.8 1.3 1.1 Tensile Impact (cm-kg/cm²) 84 60 30 26 32 HDT @ 1.82 MPa (264 psi) (°C) 104 126 115 103 101 Limiting Oxygen Index (%) 24 24 33 40 40 Tg (°C) 117 124 123 87 85 85 85 Tm (°C) 312 313 307 281 280 279 277 Degradation Temp. (°C) 369 415 404 427 467 Mold Temperature (°C) 93 93 93 93 93 Barrel Temperature (°C) Rear Zone 310 293 293 293 282 Front Zone 318 304 304 304 288 Nozzle 318 304 304 304 288 EXAMPLES 5-7 Glass fiber-filled compositions were prepared from the blends of EXAMPLES 2-4 and the neat polyphthalamide and polyphenylene sulfide resins used to prepare such blends. The filled materials were prepared by grinding the blends or neat resins to about 2 mm particle size and then physically mixing the same with commercially available, 0.32 cm long glass fibers identified as PPG 3540 from PPG Industries, Inc., in amounts sufficient to yield filled compositions containing 33 wt. % glass fibers based on weight of the filled compositions. Physical mixing was accomplished using the bucket tumbler as in EXAMPLE 2. Test bars were molded under conditions shown in TABLE 2 and otherwise according to the procedure and under conditions of EXAMPLE 2. Test bars were evaluated as in EXAMPLE 2 and results are reported in TABLE 2. Example E 5 6 7 F Blend or Neat Resin from Example A 2 3 4 D UTS (kg/cm²) 1909 2346 1402 1437 1564 Elongation at Break (%) 4.0 3.8 2.2 2.5 2.7 Flexural Strength (kg/cm²) 2875 3396 2269 2494 2381 Flexural Modulus (x 10³ kg/cm²) 105 116 116 130 121 Notched Izod (cm-kg/cm) 17.4 17.4 19.6 17.4 16.4 Tensile Impact (cm-kg/cm²) 228 231 129 162 160 HDT @ 1.82 MPa (264 psi) (°C) 282 292 273 275 271 Mold Temperature (°C) 93 93 93 93 93 Barrel Temperature (°C) Rear Zone 310 310 310 310 310 Front Zone 321 321 321 321 321 Nozzle 321 321 321 321 321 EXAMPLES 8-10 Following essentially the procedure of EXAMPLE 2, a series of blends was prepared from Polyphthalamide A prepared in EXAMPLE 1 and a polyphenylene sulfide, identified as Tophren T-4 polyphenylene sulfide from Tophren Co. Ltd., having a melting point of 280°C. Test bars were prepared and evaluated as in EXAMPLE 2, results and molding conditions being shown in TABLE 3 for the blends as well as the neat resins, the latter having been processed in the ZSK-30 extruder in similar manner to provide comparable thermal history. Results are reported in TABLE 3 wherein the polyphenylene sulfide is designated "G." Example A 8 9 10 G Polyphthalamide/Polyphenylene Sulfide (wt.%) 100/0 90/10 70/30 50/50 0/100 UTS (kg/cm²) 754 803 571 345 486 Elongation at Break (%) 3.2 3.7 2.5 1.4 1.8 Flexural Strength (kg/cm²) >1556 1409 1310 860 1050 Flexural Modulus (x 10³ kg/cm²) 33.5 35.6 36.1 37.3 37.8 Notched Izod (cm-kg/cm) 3.3 3.1 2.6 1.3 1.3 Tensile Impact (cm-kg/cm²) 84 93 86 45 39 HDT @ 1.82 MPa (264 psi) (°C) 104 110 111 111 114 Tg (°C) 117 108 108 110 86 Tm (°C) 312 306 280 283 280 Degradation Temp. (°C) 369 412 409 407 414 Water Absorption (wt. % after 24 hours) 0.66 0.58 0.44 0.26 0.06 Retained UTS (% after 24 hrs in boiling MeOH) 70 94 100 112 94 Mold Temperature (°C) 93 93 93 93 104 Barrel Temperature (°C) Rear Zone 310 310 310 310 282 Front Zone 318 318 318 318 288 Nozzle 318 318 318 318 288 EXAMPLES 11-14 Following essentially the procedure of EXAMPLE 2, a series of blends was prepared from the polyphenylene sulfide used in EXAMPLE 2 and Polyphthalamide B from EXAMPLE 1. Test bars were prepared from the blends and the neat resins, processed in like manner to provide comparable thermal history, and tested as in EXAMPLE 2, results and molding conditions being reported in TABLE 4. Also reported in the table are results for test bars molded from a commercial pellet grade polyphenylene sulfide, Ryton® R-6 Polyphenylene Sulfide from Phillips Petroleum Company. That material is designated "H" in the table. EXAMPLES 15-18 EXAMPLES 11-14 were repeated except that the extruder was equipped with kneading blocks to promote better blending. Results and conditions are reported in TABLE 5. EXAMPLES 19-22 Following essentially the procedure of Example 2, a series of blends was prepared from Polyphthalamide C from Example 1 and Tophren T4 polyphenylene sulfide from a different lot than that used in EXAMPLES 8-10. The polyphenylene sulfide melted at 275°C and is designated "I" in TABLE 6. Test bars prepared as in Example 2 from the blends and from the neat resins, processed in like manner in the ZSK-30 extruder, were evaluated, results and molding conditions being reported in TABLE 6. COMPARATIVE EXAMPLE I A series of blends was prepared from the polyphenylene sulfide used in EXAMPLE 2 and a commercial nylon 66 identified as Celanese 1000-1. The blends were prepared as in EXAMPLE 2 except that the extruder setting temperature was 288°C instead of 299°C in zones 4-8. Test bars were prepared from the blends and from the neat resins, processed in the ZSK-30 extruder in like manner, and tested as in EXAMPLE 2, results and molding conditions being shown in TABLE 7. EXAMPLES 23-25 Following essentially the procedure of EXAMPLE 1, a polyphthalamide having a melting point of 297°C, melt crystallization temperature of 245°C and inherent viscosity of about 1.02 dl/g (hereinafter Polyphthalamide "O",) was prepared from terephthalic acid, isophthalic acid, adipic acid and hexamethylene diamine in a mole ratio of 60:15:25:100. Pressure in the jacketed tube was about 686 kPa (7.0 kg/cm², 100 psig), temperature of the circulating heat exchange fluid was about 335-345°C and extruder barrel temperature was 310-320°C. Polyphthalamide O then was blended with varying amounts of polyphenylene sulfide of the type used in EXAMPLE 2 following essentially the procedure of that example and the blends and neat resins were tested. Results and molding conditions were as follows: Example O 23 24 25 D Polyphthalamide/Polyphenylene Sulfide (wt %) 100/0 90/10 50/50 10/90 0/100 UTS (kg/cm²) 937 944 387 345 373 Elongation at Break (%) 6.9 4.0 1.4 1.1 1.2 Flexural Modulus (x 10³ kg/cm²) 34.6 35.9 36.5 38.6 40.4 Notched Izod (cm-kg/cm) 3.8 4.4 1.1 1.1 1.1 Flexural Strength (kg/cm²) 1191 1479 874 803 867 Tg (°C) 104 101 99 87 88 Tm (°C) 307 307 305 305 278 279 278 276 HDT @ 1.82 MPa (264 psi) (°C) 107 105 106 92 100 Degradation Temp. (°C) 372 372 391 382 427 Mold Temperature (°C) 93 93 93 93 93 Barrel Temperature (°C) Rear Zone 310 293 293 293 277 Front Zone 316 304 304 304 282 Nozzle 316 304 304 304 282 Solvent resistance of the blends from these examples were determined by measuring UTS of test bars before and after immersion in boiling (65°C) methanol for 24 hours and in acetic acid at 93°C for 24 hours and calculating retained UTS as a percentage of UTS before immersion. Solvent exposures were performed according to ASTM D-543. Results are shown in TABLE 9. Example O 23 24 25 D Polyphthalamide/Polyphenylene Sulfide (wt %) 100/0 90/10 50/50 10/90 0/100 UTS (kg/cm²) 1106 902 317 366 416 UTS (kg/cm²) after 24 hours in: 65°C Methanol 672 591 334 244 361 93°C Acetic Acid 451 381 331 365 404 Retained UTS (%) after 24 hours in: 65°C Methanol 61 66 105 67 87 93°C Acetic Acid 41 42 104 100 97 COMPARATIVE EXAMPLE II For purposes of comparison, a polyphthalamide of 50:50:100 terephthalic acid, isophthalic acid and hexamethylene diamine, corresponding to the description of the amorphous polyamide, Zytel® 330, given in U.S. Patent No. 4,258,335, was prepared following essentially the procedure of EXAMPLE 1 and then blended with polyphenylene sulfide following essentially the procedure of EXAMPLE 2. The blends were tested; results and molding conditions are reported in TABLE 10 in which the polyphthalamide is designated "P". Heat deflection temperature at 1.82 MPa (264 psi), according to ASTM D-648, of Polyphthalamide P compounded with 33 weight percent glass fibers as in Examples 5-7 and molded using a mold heated at 104°C was 133°C. Example P Q R S D Polyphthalamide/Polyphenylene Sulfide (wt %) 100/0 90/10 50/50 10/90 0/100 UTS (kg/cm²) 834 852 387 303 324 Elongation at Break (%) 9.2 4.9 1.6 1.0 1.1 Flexural Modulus (x 10³ kg/cm²) 31.1 30.2 33.7 39.2 40.4 Notched Izod (cm-kg/cm) 8.2 6.5 1.1 1.1 1.1 Flexural Strength (kg/cm²) NB NB 831 768 852 Tg (°C) 125 130 86 93 91 Tm (°C) 261 273 279 280 279 HDT @ 1.82 MPa (264 psi) (°C) 118 114 112 103 99 Degradation Temp. (°C) 396 384 404 410 418 Mold Temperature (°C) 93 93 93 93 93 Barrel Temperature (°C) Rear Zone 277 277 277 277 277 Front Zone 282 282 282 282 282 Nozzle 282 282 282 282 282 Comparing results in TABLE 10 with those reported in TABLES 1, 3-6 and 8 with respect to blends according to the invention it can be seen that there was generally a greater decline in mechanical properties, such as UTS and Notched Izod, of the comparative blends with increasing levels of polyphenylene sulfide than shown by the invented blends. COMPARATIVE EXAMPLE III For purposes of comparison, blends of polyphenylene sulfide of the type used in EXAMPLE 2 with a commercial polyphthalamide designated Zytel® 330 available from E. I. DuPont de Nemeurs Co. were prepared following essentially the procedure of EXAMPLE 2. Zytel® 330 is believed to be an amorphous polyamide of 30:70 terephthalic acid and isophthalic acid with hexamethylene diamine plus a small amount of bis-p-aminocyclohexyl(methane). The blends were tested; results and molding conditions are reported in TABLE 11 in which the Zytel® 330 is identified as "T." Heat deflection temperature at 1.82 MPa (264 psi) according to ASTM D-648 of the Zytel® 330 compounded with 33 weight percent glass fibers as in EXAMPLES 5-7 and molded using a mold heated at 104°C was 129°C. Example T U V W D Polyphthalamide/Polyphenylene Sulfide (wt %) 100/0 90/10 50/50 10/90 0/100 UTS (kg/cm²), 838 810 606 331 359 Elongation at Break (%) 4.3 4.0 2.5 1.1 1.1 Flexural Modulus (x 10³ kg/cm²) 30.8 30.3 33.4 37.9 39.8 Notched Izod (cm-kg/cm) 4.9 4.4 2.2 0.5 0.5 Flexural Strength (kg/cm²) 1339 1303 1240 705 852 Tg (°C) 130 131 87 89 88 Tm (°C) * 278 279 277 277 HDT @ 1.82 MPa (264 psi) (°C) 116 113 113 105 104 Degradation Temp. (°C) 379 395 398 403 427 Mold Temperature (°C) 93 93 93 93 93 Barrel Temperature (°C) Rear Zone 277 277 277 277 277 Front Zone 282 282 282 282 282 Nozzle 282 282 282 282 282 *Polyphthalamide T lacked a definite melting point, indicating the substantially amorphous nature thereof. Solvent resistance of these blends was determined as in EXAMPLES 23-25; results are reported in TABLE 12. Example T U V W D Polyphthalamide/Polyphenylene Sulfide (wt %) 100/0 90/10 50/50 10/90 0/100 UTS (kg/cm²) 930 733 585 345 416 UTS (kg/cm²) after 24 hours in: 65°C Methanol * * * 217 361 93°C Acetic Acid * * * 279 404 Retained UTS (%) after 24 hours in: 65°C Methanol * * * 63 87 93°C Acetic Acid * * * 81 97 * Specimens disintegrated and could not be tested. Comparing the results in TABLES 11 and 12 with those in TABLES 1, 3-6, 8 and 9, it can be seen that the comparative, amorphous polyphthalamide component-containing blends and the invented blends, while generally comparable in mechanical properties, were considerably different in retention of ultimate tensile strength after exposure to methanol and acetic acid, the invented blends showing far superior property retention. EXAMPLES 26-28 EXAMPLES 23-25 were repeated except that a different ZSK-30 extruder was used. Results and molding conditions are reported in TABLE 13. Example O 26 27 28 D Polyphthalamide/Polyphenylene Sulfide (wt %) 100/0 90/10 50/50 10/90 0/100 UTS (kg/cm²) 993 909 395 359 324 Elongation at Break (%) 4.4 3.8 1.4 1.2 1.1 Flexural Modulus (x 10³ kg/cm²) 35.6 36.5 37.1 39.2 40.4 Notched Izod (cm-kg/cm) 3.8 2.7 1.1 1.1 1.1 Flexural Strength (kg/cm²) 1479 1515 852 845 852 Tg (°C) 104 102 105 86 88 91 Tm (°C) 308 308 305 278 275 279 HDT @ 1.82 MPa (264 psi) (°C) 104 115 109 103 99 Degradation Temp. (°C) 386 380 391 375 418 Mold Temperature (°C) 93 93 93 93 93 Barrel Temperature (°C) Rear Zone 310 293 293 293 277 Front Zone 316 304 304 304 282 Nozzle 316 304 304 304 282 EXAMPLES 29-31 The blends prepared in EXAMPLES 23-25 and neat resins of the type used in those examples were dry blended with 33 weight percent glass fibers and the filled blends were molded and tested following essentially the procedure of EXAMPLES 26-28; results and molding conditions are shown in TABLE 14. Example X 29 30 31 Y Blend or Neat Resin From Example 0 23 24 25 D Polyphthalamide/Polyphenylene Sulfide (wt %) 100/0 90/10 50/50 10/90 0/100 UTS (kg/cm²) 1804 2078 1261 1233 1423 Elongation at Break (%) 3.6 4.1 2.2 2.2 2.7 Flexural Modulus (x 10³ kg/cm²) 100 102 106 116 118 Flexural Strength (kg/cm²) 2755 2832 1853 2029 2071 Notched Izod (cm-kg/cm) 14.2 14.2 15.8 14.7 10.4 HDT @ 1.82 MPa (264 psi) (°C) 289 288 273 269 267 Mold Temperature (°C) 104 104 104 104 104 Barrel Temperature (°C) Rear Zone 310 293 293 293 277 Front Zone 316 304 304 304 282 Nozzle 316 304 304 304 282 COMPARATIVE EXAMPLE IV The procedure of EXAMPLES 29-31 was repeated using the blends and neat resins of COMPARATIVE EXAMPLE II; results and molding conditions are shown in TABLE 15. Example Z AA BB CC DD Blend or Neat Resin From Example P Q R S D Polyphthalamide/Polyphenylene Sulfide (wt %) 100/0 90/10 50/50 10/90 0/100 UTS (kg/cm²) 2106 2092 1324 1282 1381 Elongation at Break (%) 4.3 4.3 2.4 2.3 2.5 Flexural Modulus (x 10³ kg/cm²) 91.3 94.1 101 110 112 Flexural Strength (kg/cm²) 2733 2846 1909 1902 2015 Notched Izod (cm-kg/cm) 13.1 13.6 16.9 18.0 13.1 HDT @ 1.82 MPa (264 psi) (°C) 133 132 250 269 269 Mold Temperature (°C) 104 104 104 104 104 Barrel Temperature (°C) Rear Zone 282 282 282 282 282 Front Zone 288 288 288 288 288 Nozzle 288 288 288 288 288 COMPARATIVE EXAMPLE V The procedure of EXAMPLES 29-31 was repeated using the blends and neat resins of COMPARATIVE EXAMPLE III; results and molding conditions are shown in TABLE 16. Example EE FF GG HH II Blend or Neat Resin From Example T U V W D Polyphthalamide/Polyphenylene Sulfide (wt %) 100/0 90/10 50/50 10/90 0/100 UTS (kg/cm²) 1980 2106 1613 1324 1423 Elongation at Break (%) 3.9 4.3 3.1 2.4 2.7 Flexural Modulus (x 10³ kg/cm²) 101 105 110 111 111 Flexural Strength (kg/cm²) 2931 3058 2177 2071 2071 Notched Izod (cm-kg/cm) 13.1 12.5 11.4 12.0 10.4 HDT @ 1.82 MPa (264 psi) (°C) 129 130 142 267 267 Mold Temperature (°C) 104 104 104 104 104 Barrel Temperature (°C) Rear Zone 277 277 277 277 277 Front Zone 282 282 282 282 282 Nozzle 282 282 282 282 282 EXAMPLES 32-34 The procedure of EXAMPLES 29-31 was repeated using the blends and neat resins of EXAMPLES 26-28; results and molding conditions are shown in TABLE 17. Example JJ 32 33 34 KK Blend or Neat Resin From Example 0 26 27 28 D Polyphthalamide/Polyphenylene Sulfide (wt %) 100/0 90/10 50/50 10/90 0/100 UTS (kg/cm²) 1733 2015 1219 1381 1381 Elongation at Break (%) 3.3 3.9 2.2 2.4 2.5 Flexural Modulus (x 10³ kg/cm²) 92.8 98.1 107 112 112 Flexural Strength (kg/cm²) 2684 2895 1994 2163 2015 Notched Izod (cm-kg/cm) 14.7 14.7 17.4 13.6 13.1 HDT @ 1.82 MPa (264 psi) (°C) 291 289 272 266 269 Mold Temperature (°C) 104 104 104 104 104 Barrel Temperature (°C) Rear Zone 310 293 293 293 277 Front Zone 316 304 304 304 282 Nozzle 316 304 304 304 282 EXAMPLE 35 This example demonstrates improved thermal endurance of the invented blends relative to the neat polyphthalamide component thereof. The polyphthalamide used in this example as a control and to prepare a blend with ten weight percent Ryton® P6 polyphenylene sulfide was prepared essentially as in EXAMPLE 1 from terephthalic acid, isophthalic acid and adipic acid, in a mole ratio of 65:25:10 and hexamethylene diamine. Elemental analysis of the polyphenylene sulfide showed 23.6 weight percent sulfur. The polyphthalamide had the following ash and elemental analyses for sulfur and copper: Ash content (%) 34.8 S content (ppm) <10 Cu content ppm 380 A 33 weight percent glass fiber-filled blend of 90 weight percent polyphthalamide and ten weight percent polyphenylene sulfide was prepared in two steps by extrusion compounding. In a first step, 2700 grams of the polyphthalmide, in the form of pellets, were blended with 300 grams of the polyphenylene sulfide, 13.5 grams talc, 16.1 grams potassium iodide, and 415 grams cupric acetate by tumbling. The blended mixture was rear fed to a ZSK-30 twin screw extruder at a rate of 10.3 kg/hr. The extruder had six independently controlled temperature zones. The temperature set points and actual zone tempratures, beginning at Zone 1 (the feed port) and ending at Zone 6 (the die) were as follows: Zone Temperature (°C) 1 2 3 4 5 6 Set 149 310 310 299 299 310 Actual 192 276 300 299 299 293 The recorded melt temperature was 307°C, screw torque was 55% and die pressure was 16.9 kg/cm². Screw speed was 100 rpm. The extruded strand was tan in color. The strand was cut into pellets by a mechanical chopper. Pellet bulk density was 0.72 g/cm³. In a second step the blend was compounded with 33 weight percent glass fibers, identified as PPG 3540 obtained from PPG Industries, Inc., which were added to the melted blend through an open port in the third heating zone of the ZSK-30 twin screw extruder. The temperature profile for this extrusion was: Zone Temperature (°C) 1 2 3 4 5 6 Set 288 321 327 324 324 319 Actual 274 310 307 318 324 316 Screw rpm was 100, torque was 65%, die pressure was 21.8 kg/cm² and melt temperature was 330°C. The tan, extruded strand was chopped into pellets with a bulk density of 0.35 g/cm³. Ashing and elemental analysis of the resulting filled blend gave the following results: Ash content (%) 32.9 S content (%) 1.63 Cu content (ppm) 370 The resin was molded into Type IV tensile specimens in an Arburg, Model 221 E injection molding machine. The initial tensile strength was 2200 kg/cm². The tensile specimens were thermally aged in groups of five at 220°C for up to 1008 hours. The tensile strength of each group after aging was determined. These results, together with results for test bars prepared and aged in like manner from the glass fiber filled polyphthalamide without polyphenylene sulfide, are shown below. % Retained Tensile Strength Time (hours) EXAMPLE 35 (90/10 Polyphthalamide/Polyphenylene Sulfide) Control (Polyphthalamide) 0 100 100 168 87.2 76.3 336 66.1 64.8 504 61.3 56.6 672 55.9 53.8 720 57.5 -- 744 57.8 52.1 840 50.2 47.3 1008 43.1 43.1 From these thermal aging results the time to 50% retention of tensile strength hereinafter "F-50" was interpolated, using both cubic polynomial and exponential fits of the data, as follows: Cubic Exponential F-50 (hours) r F-50 (hours) r EXAMPLE 35 881 .989 840 .975 Control 810 .998 768 .974 where r is the correlation coefficient. Both treatments of the data demonstrate that the resin containing the polyphenylene sulfide had about a 10% longer F-50 at 220°C. EXAMPLE 36 A second 90/10 polyphthalamide/polyphenylene sulfide blend was prepared using the same procedures and materials as described above, except that the polyphenylene sulfide used was Ryton P4, which had been advanced in molecular weight by solid state polymerization for 16 hours at 238°C. Compounding conditions for the first pass through the extruder were as follows: Zone Temperature (°C) 1 2 3 4 5 6 Set 149 310 310 299 299 310 Actual 184 288 299 299 299 305 Torque was 60%, die pressure was 12 kg/cm², screw rpm was 100, melt temperature was 314°C and feed rate was 10.3 kg/hr. Pellet bulk density was 0.70 g/cm³. The pellets were tan in color. The conditions for the second extrusion pass were as follows: Zone Temperature (°C) 1 2 3 4 5 6 Set 288 321 327 324 324 319 Actual 271 304 310 316 318 313 The melt temperature was 319°C, and the screw speed was 100 rpm. Ash and elemental analysis of the blend the gave following results: Ash content (%) 35.8 S content (%) 1.74 Cu content (ppm) 330 Type I tensile specimens of this sample were thermally aged at 220°C for 120 hours with the blend from EXAMPLE 35 and the control used in the example. The initial and percent retained tensile strengths were as follows: Tensile Strength Initial (kg/cm²) Retained (%) EXAMPLE 36 2140 86 EXAMPLE 35 2070 89 CONTROL 2400 83

Claims: A composition comprising a blend of:- 1-99 weight percent of a polyphthalamide comprising at least two recurring units selected from A, B and C, wherein the mole ratios of dicarboxylic acid moieties in the units A, B and C is 40-99: 0-35: 0-60 which when filled with 33 weight percent glass fibres has a heat deflection temperature at 1.82 MPa (264 psi) according to ASTM D-648 of at least 240°C measured using a mould heated to above Tg but below Tcm of the polyphthalamide, wherein R, R₁ and R₂ are independently divalent hydrocarbyl radicals, and 99-1 percent of a polyarylene sulphide component having a melting point of 285°C or lower, wherein the polyphthalamide component has a melting point exceeding that of the polyarylene sulphide component by at least 15°C. The composition of claim 1 further characterised in that R, R₁ and R₂ ae independently divalent hydrocarbyl radicals of 2 to 14 carbon atoms. The composition of Claim 2 characterized in that R, R₁ and R₂ comprise hexamethylene. The composition of Claim 2 or Claim 3 further characterized in that the mole ratio of dicarboxylic acid moieties in the units A, B and C is 65-90:25-0:35-5. The composition of Claim 2 or Claim 3 further characterized in that the mole ratio of dicarboxylic acid moieties in the units A, B and C is 40-65:0-15:20-60. The composition of Claim 2 or Claim 3 further characterized in that the mole ratio of dicarboxylic acid moieties in the units A, B and C is 70-99:30-1:0. The compositon of any of claims 1-6 further characterized in that the polyphthalamide component is a poly(hexamethylene phthalamide) component which, when filled with 33 weight percent glass fibers, has a heat deflection temperature at 1.82 MPa (264 psi) according to ASTM D-648 of at least 240°C, consisting essentially of at least two recurring units selected from the group consisting of: in proportions such that the mole percentage of dicarboxylic acid moieties in B based on total dicarboxylic acid moieties in A, B and C is 0 to 35 percent; provided, that when said percentage is 19 to 35 percent, the mole percentage of dicarboxylic acid moieties in A based on dicarboxylic acid moieties in A, B and C is at least four times said mole percentage of dicarboxylic acid moieties in B minus 75 percent. The composition of any of claims 1-7 further characterized in that 10 to 90 weight percent of the polyphthalamide component is present at 90 to 10 weight percent of the polyarylene sulfide component is present, such weight percentages being based on the total weight of said polyphthalamide and polyarylene sulfide components. The composition of any of claims 1-8 further characterized in that the polyarylene sulfide component comprises a polyphenylene sulfide. The composition of any of claims 1-9 additionally comprising a fibrous or particulate material. The composition of any of claims 1-10 further characterized in that the amount of particulate or fibrous material is about 10 to about 60 weight percent based on weight of the composition. A molded object comprising the composition of any of claims 1-11. A fiber comprising the composition of any of claims 1-9.

Inventors: CHEN YU-TSAI, SINCLAIR DAVID PETER, CHEN, YU-TSAI, SINCLAIR, DAVID PETER
Applicants: AMOCO CORP, AMOCO CORPORATION
Application year: 1989
Main classification: C08L77
IPC codes: C08K7, C08K3, D01F6, C08L77, C08L81