Abstract:
There are provided plasticized thermoplastic compositions useful for molding which comprise a polyphenylene ether resin, a plasticizer, a mineral reinforcing agent, e.g., aluminum silicate, titanium dioxide, zinc oxide, antimony oxide, and the like, and optionally, an impact modifier. The compositions possess improved stiffness properties with unexpectedly significant retention of ductility in comparison with corresponding compositions which do not contain the mineral reinforcing agent.

Description:
This is a continuation of application Ser. No. 334,636 filed Dec. 28, 1981, now abandoned, which, in turn, is a continuation of Ser. No. 755,025, filed Dec. 28, 1976, now abandoned. 
    
    
     This invention relates to mineral reinforced, plasticized polyphenylene ether compositions. More particularly, it relates to thermoplastic molding compositions comprising a polyphenylene ether resin with or without an impact modifier, a plasticizing amount of a plasticizer, and a mineral reinforcing agent which provides improved stiffness with unexpectedly significant retention of ductility. 
     BACKGROUND OF THE ART 
     The polyphenylene ether resins are well known in the art as a class of thermoplastics which possess a number of outstanding physical properties. They can be prepared, in general, by oxidative and non-oxidative methods, such as are disclosed, for example, in Hay, U.S. Pat. Nos. 3,306,874 and 3,306,875 and Stamatoff, U.S. Pat. Nos. 3,257,357 and 3,257,358, which are incorporated herein by reference. 
     It is known that the polyphenylene ether resins can be combined with impact modifiers to obtain improved impact resistance and other mechanical properties. Suitable impact modifiers for polyphenylene ether resins are disclosed in Cizek, U.S. Pat. No. 3,383,435, incorporated herein by reference, and elsewhere. 
     As employed herein the term &#34;plasticized&#34; is used to describe compositions having a sufficient amount of plasticizer to reduce the temperature of optimum extrusion by at least about 25° F., and normally from about 25° to about 100° F. 
     It has now been surprisingly discovered that plasticized polyphenylene ether compositions comprising a mineral reinforcing agent, possess enhanced stiffness, as measured by flexural modulus and flexural strength, in comparison with corresponding compositions without said agent. Moreover, it is unexpected that the improvements in stiffness properties are obtained along with a significant retention of ductility, as measured by tensile elongation and impact resistance. 
     DESCRIPTION OF THE INVENTION 
     In its broadest aspects, the present invention comprises reinforced, plasticized thermoplastic compositions suitable for molding or shaping, i.e., by compression molding, extrusion, calendering, and the like, which possess enhanced stiffness in comparison with the corresponding unreinforced compositions, the compositions comprising: 
     (a) a polyphenylene ether resin alone or in combination with an impact modifier; 
     (b) a plasticizer therefor in an amount at least sufficient to reduce the temperature of optimum extrusion at least about 25° F.; and 
     (c) a mineral reinforcing agent in an amount at least sufficient to provide enhanced stiffness in comparison with a corresponding unreinforced composition. 
     In general, the polyphenylene ether resins of the compositions are of the family having structural units of the formula: ##STR1## wherein the oxygen ether atom of one unit is connected to the benzene nucleus of the next adjoining unit, n is a positive integer and is at least 50, and each Q is a monovalent substituent selected from the group consisting of hydrogen, halogen, hydrocarbon radicals free of a tertiary alpha-carbon atom, halohydrocarbon radicals having at least two carbon atoms between the halogen atom and the phenyl nucleus, hydrocarbonoxy radicals and halohydrocarbonoxy radicals having at least two carbon atoms between the halogen atom and the phenyl nucleus. 
     Preferably, the polyphenylene ether resins are selected from those of the above formula wherein each Q is alkyl, most preferably having from 1 to 4 carbon atoms. Illustratively, members of this class include poly(2,6-dimethyl-1,4-phenylene)ether; poly(2,6-diethyl-1,4-phenylene)ether; poly(2-methyl-6-ethyl-1,4-phenylene)ether; poly(2-methyl-6-propyl-1,4-phenylene)ether; poly(2,6-dipropyl-1,4-phenylene)ether; poly(2-ethyl-6-propyl-1,4-phenylene)ether; and the like. 
     Especially preferred is poly(2,6-dimethyl-1,4-phenylene)ether, preferably having an intrinsic viscosity of about 0.45 deciliters per gram (dl./g.) as measured in chloroform at 30° C. 
     The preparation of polyphenylene ether resins corresponding to the above formula is described in the above-mentioned patents of Hay and Stamatoff. 
     The choice of a plasticizer is not critical and any of the conventional materials used for this purpose can be employed. Preferably, component (b) will be selected from among phthalate and phosphate plasticizing materials, and especially phosphate plasticizers. 
     The phosphate plasticizer is preferably a compound of the formula: ##STR2## wherein R 1 , R 2  and R 3  are the same or different and are alkyl, haloalkyl, cycloalkyl, halocycloalkyl, aryl, haloaryl, alkyl substituted aryl, haloalkyl substituted aryl, aryl substituted alkyl, haloaryl substituted alkyl, hydroxyalkyl, hydroxyaryl, hydroxyalkaryl, halogen and hydrogen. 
     Examples include cresyl diphenyl phosphate, 2-ethylhexyl diphenyl phosphate, tricresyl phosphate, triiosopropylphenyl phosphate, triphenyl phosphate, triethyl phosphate, dibutyl phenyl phosphate, diethyl phosphate, cresyl diphenyl phosphate, isooctyl diphenyl phosphate, tributyl phosphate, 2-ethylhexyl diphenyl phosphate, isodecyl diphenyl phosphate, isodecyl dicresyl phosphate, didecyl cresyl phosphate, tri-n-hexyl phosphate, di-n-octyl phenyl phosphate, di-2-ethyl-hexyl phenyl and tri-2-ethylhexyl phosphate or mixtures thereof. Especially preferred are aromatic phosphates, e.g., triphenyl phosphate. 
     Examples of phthalate plasticizers include dibenzyl phthalate, phenyl cresyl phthalate, diethyl phthalate, dimethyl phthalate, phenyl benzyl phthalate, butyl benzyl phthalate, butyl cyclohexyl phthalate, dibutyl phthalate, octyl cresyl phthalate, diphenyl phthalate, di-n-hexyl phthalate, disohexyl phthalate, butyl octyl phthalate, butyl decyl phthalate, diisooctyl phthalate, di-2-ethylhexyl phthalate, di-n-octyl phthalate, diisononyl phthalate, diisodecyl phthalate, di-2-propyl heptyl phthalate, di-n-nonyl phthalate, di-n-decyl phthalate and ditridecyl phthalate. 
     The plasticizer (b) is added in amounts which will be sufficient to provide a plasticized composition within the meaning of the term described above. In general, the plasticizer is present in amounts ranging from at least about 5 parts per hundred parts of resinous components combined, preferably from about 5 to about 100 parts per hundred parts of resin. 
     Illustratively, the mineral reinforcement is selected from among talcs, aluminum silicate, e.g., clay, hydrated, anhydrous or calcined clay, zinc oxide, titanium dioxide, antimony oxide, barium sulfate, precipitated or natural calcium carbonate, zinc sulfide, and the like. Especially preferred is hydrated aluminum silicate. 
     Amounts of the mineral reinforcing agent will vary depending on the formulation and needs of the particular composition. In preferred compositions, however, the mineral reinforcement will be present in at least about 5 parts per hundred parts of resins combined. Especially preferred embodiments will comprise anywhere from about 5 to about 150 parts of mineral reinforcement per hundred parts of resin plus plasticizer. 
     The nature of the impact modifiers for the polyphenylene ether or polyphenylene ether/polystyrene resin is not critical and any of the elastomeric polymers and copolymers which are conventionally employed to improve impact properties in thermoplastic compositions can be used. Illustratively, the impact modifiers can be selected from among elastomeric A-B-A 1  block copolymers wherein terminal blocks A and A 1  are the same or different and are derived from a vinyl aromatic compound, e.g., styrene, α-methyl styrene, vinyl toluene, vinyl xylene, vinyl naphthalene, and the like, and center block B is derived from a conjugated diene, e.g., butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl butadiene, and the like. 
     These can be made by an organometallic initiated polymerization process using, for example, sodium or lithium metal or an organic derivative thereof. The diene monomers can be polymerized with a monofunctional or difunctional initiator, as is described in Kennedy et al, Interscience Publishers, Vol. 23, Part II (1969), pages 553-559. Other methods of preparation are described in Zelinski, U.S. Pat. No. 3,251,905 and Holden et al, U.S. Pat. No. 3,231,635, the disclosures of which are incorporated herein by reference. 
     The relative ratios of the polymer units in the A-B-A 1  block copolymers can vary broadly. It is preferred that the center block B have a molecular weight greater than that of the combined terminal blocks, however, to obtain optimum impact strength and solvent resistance. In general, the molecular weight of each of the respective terminal blocks will range from about 2,000 to about 100,000 and the molecular weight of the center block will range from about 65,000 to about 1,000,000. 
     Examples include the Kraton resins, commercially available from Shell Chemical Co., Polymers Division, e.g., K-1101 (polystyrene-polybutadiene-polystyrene), K-1102 (polystyrene-polybutadiene-polystyrene), and K-1107 (polystyrene-polyisoprene-polystyrene). 
     The hydrogenated A-B-A 1  block copolymers are also well known. In general, these are block copolymers of the A-B-A 1  type in which terminal blocks A and A 1  are the same or different and, prior to hydrogenation, comprise homopolymers or copolymers derived from vinyl aromatic hydrocarbons and, especially, vinyl aromatics wherein the aromatic moiety can be either monocyclic or polycyclic. Examples of the monomers are styrene, α-methyl styrene, vinyl xylene, ethyl vinyl xylene, vinyl naphthalene, and the like. Center block B will always be derived from a conjugated diene, e.g., butadiene, isoprene, 1,3-pentadiene, and the like. Preferably, center block B will be comprised of polybutadiene or polyisoprene. 
     The preparation of hydrogenated A-B-A 1  block copolymers is described in Jones, U.S. Pat. No. 3,431,323, the disclosure of which is incorporated herein by reference. 
     Examples include the Kraton G resins, commercially available from Shell Chemical Co., Polymers Division, e.g., G-GXT-0650, G-GXT-0772, G-GXT-0782 and G-6521. 
     Radial teleblock copolymers of a vinyl aromatic compound, a conjugated diene and a coupling are also suitable impact modifiers for the compositions of this invention. These are branched polymers having segments, or blocks, comprised of a conjugated diene polymer, and a vinyl aromatic polymer, together with a coupling agent, wherein in the copolymer structure chains of the diene polymer radiate outwards from a coupling agent, each chain terminating at its other end with a block of the vinyl aromatic polymer. 
     The radial teleblock copolymers are known in the art. They are described in ADHESIVES AGE, December, 1971, pages 15-20 and RUBBER WORLD, January, 1973, pages 27-32, which were incorporated herein by reference. The preparation of these copolymers is described in Zelinski et al, U.S. Pat. No. 3,281,383, also incorporated herein by reference. 
     Examples of commercially available radial teleblock copolymers are the Solprene resins of Phillips Petroleum Company designated as Solprene 406 (containing about 60 parts by weight of butadiene units and about 40 parts by weight of styrene units), Solprene 411 (containing about 70 parts by weight of butadiene units and about 30 parts by weight of styrene units), Solprene 414 (containing about 60 parts by weight of butadiene units and about 40 parts by weight of styrene units), Solprene 417 (containing about 20 parts by weight of butadiene units and about 80 parts by weight of styrene units), and S411P (containing about 70 parts by weight of butadiene units and about 30 parts by weight of styrene units). These materials also include a relatively minor amount of coupling agent, e.g., less than 1 part by weight of coupling agent per 100 parts of polymer. 
     Also included are hydrogenated radial teleblock copolymers of a vinyl aromatic compound, a conjugated diene and a coupling agent, such as Solprene 512, commercially available from Phillips Petroleum Co. 
     The impact modifier can also be selected from acrylic resin modified diene rubber containing resins. Preferably, these will be of the group consisting of a resinous composition of a poly(alkylene methacrylate) grafted on to a butadiene-styrene copolymer backbone or an acrylonitrile-butadiene-styrene terpolymer backbone, or a resinous composition of a mixture of a poly(alkylmethacrylate) and a butadiene-styrene copolymer or an acrylonitrile-butadiene-styrene terpolymer. 
     A preferred commercially available impact modifier of this type is Acryloid KM611, sold by Rohm and Haas Co., which is an acrylic/styrene/styrene-butadiene terpolymer. 
     The aforementioned acrylic resin modified elastomers can be prepared by well known techniques, such as those described in U.S. Pat. No. 2,943,074 and U.S. Pat. No. 2,857,360, which are incorporated herein by reference. 
     The impact modifier can also be a graft copolymer of a vinyl aromatic compound and a diene, preferably comprising from about 75 to about 10% by weight of a vinyl aromatic monomer and from about 25 to about 90% by weight of a conjugated diene. By way of illustration, the aromatic monomer can be selected from among styrene, α-methyl styrene, vinyl toluene, vinyl xylene, and the like, and the diene can be selected from among butadiene, isoprene, and the like. Graft copolymers of styrene and styrene-butadiene are preferred. 
     An example of a preferred commercially available graft copolymer is Blendex 525, sold by Marbon Chemical Co. 
     The compositions of this invention can be prepared by conventional methods. Preferably, each of the ingredients is added as part of a blend premix, and the blend is passed through an extruder at an extrusion temperature of from about 500° to about 625° F., dependent on the needs of the particular composition. The strands emerging from the extruder may be cooled, chopped into pellets, and molded or otherwise worked to any desired shape. 
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following examples are illustrative of the compositions of this invention. They are not to be construed as limiting the invention to the particular embodiments shown therein. All parts are by weight. 
     Units for the properties shown in the following Examples are as follows, unless otherwise indicated: 
     Tensile yield, psi 
     Tensile break, psi 
     Tensile elongation, % 
     Flexural modulus, psi 
     Flexural strength, psi 
     Melt viscosity, at 540° F., 1500 sec -1 , poise 
     Gloss, 45° surface gloss, dimensionless units 
     UL-94-Underwriters Laboratories Bulletin 94, sec/sec. 
     Izod Impact strength, ft.lbs./in.n. 
     Gardner Impact strength, in.lbs. 
     Heat distortion temperature, °F. 
     Coefficient of Linear Thermal Expansion (CLTE), in/in °F., measured from -30° C. to 65° C. 
    
    
     EXAMPLES 1-4 
     Self-extinguishing, plasticized blends of 78 parts of poly(2,6-dimethyl-1,4-phenylene ether) resin, intrinsic viscosity about 0.45 deciliters/gram as measured in chloroform at 30° C., 22 parts of triphenyl phosphate flame retardant plasticizer, 5 parts of styrene-butadiene-styrene block copolymer (Kraton 1101, Shell Chemical Co., Polymers Division), 1.5 parts of polyethylene and 20 parts of various mineral reinforcing agents, as shown, are compounded and extruded at a temperature of 580° F. The extrudate is chopped into pellets, molded into test bars at a temperature of about 520° F., and evaluated for mechanical and flame resistance properties. For purposes of comparison, a blend of the same ingredients in the same amounts is prepared, but without a filler. The mineral reinforcements and test results are shown in Table 1. 
     
                                           TABLE 1__________________________________________________________________________        Tensile       Impact  Flexural  Melt UL-94ExampleFiller  Yield            Break                Elongation                      Izod                         Gardner                              Modulus                                   Strength                                        Viscosity                                             Flame__________________________________________________________________________                                             test1    clay, untreated.sup.a        9,600            10,100                64    10.3                         242  428,000                                   14,100                                        3,500                                             1.3/2.02    clay, treated.sup.b        9,600            10,000                62    11.0                         233  --   --   --   --3    clay, treated.sup.c        9,700             9,800                54    3.9                         233  --   --   --   --  4A*NONE    9,000             9,100                70    7.8                         243  308,000                                   12,800                                        2,900                                             1.0/2.7__________________________________________________________________________ *control .sup.a Al--Sil--Ate NCF, Freeport Kaolin Co. .sup.b OX1 coated clay, Freeport Kaolin Co. .sup.c OX2 coated clay, Freeport Kaolin Co. 
    
     EXAMPLES 5-10 
     Self-extinguishing, plasticized compositions of 78 parts of poly(2,6-dimethyl-1,4-phenylene ether), 22 parts of triphenyl phosphate flame retardant plasticizer, 5 parts of styrene-butadiene-styrene block copolymer (Shell&#39;s Kraton 1101), 1.5 parts of polyethylene and a clay filler (Al-Sil Ate NCF, Freeport Kaolin Co.) in the amounts shown are prepared and molded as in Examples 1-4. The physical properties are summarized in Table 2. 
     
                                           TABLE 2__________________________________________________________________________          Tensile     Impact  FlexuralExamplePhr (% by weight)          Yield              Break                  Elong.                      Izod                         Gardner                              Mod.                                  Str.                                      UL-94                                           CLTE__________________________________________________________________________5    11.1 (10)  9,200              9,300                  65  10.1                         253  401,000                                  14,000                                      1.3/5.7                                           4.0 × 10.sup.-56    25   (20)  9,900              9,800                  64  7.0                         222  492,000                                  15,600                                      1/3.3                                           3.4 × 10.sup.-57    33   (25) 10,200              9,900                  50  2.5                         202  562,000                                  16,100                                      2/6  --8    43   (30) 10,100              9,700                  39  1.4                         132  673,000                                  16,400                                      2.3/13                                           2.8 × 10.sup.-59    67   (40) 11,300              10,900                  21  1.3                          52  717,000                                  17,800                                      1.7/10.7                                           --10   100  (50) 12,700              12,700                   8  0.7                         less than                              --  --  3/45 --                          10  10A*NONE       8,800              9,400                  72  7.8                         243  336,000                                  13,400                                      1.7/3                                           4.8 × 10__________________________________________________________________________                                           .sup.-5 *control phr signifies part of clay per hundred parts of resin plus plasticizer CLTE Coefficient of Linear Thermal Expansion 
    
     It is shown that even with amounts of reinforcement as high as 67 phr (40%), in Example 9, a significant amount of ductility, as measured by tensile elongation and impact strength, is retained as compared with the unreinforced control (10A*). 
     EXAMPLES 11-13 
     Blends of poly(2,6-dimethyl-1,4-phenylene ether) resin, mineral oil, styrene-butadiene-styrene block copolymer (Kraton 1101), polyethylene and a clay reinforcing filler are compounded, extruded and molded as in Examples 1-4. The formulations and physical properties are summarized in Table 3. 
     
                       TABLE 3______________________________________EXAMPLE      11      11A*    12    13    13A*______________________________________Ingredients(parts by weight)poly(2,6-dimethyl-1,4-        78      78      78    85    85phenylene ether)mineral oil (Kaydol)        22      22      22    15    15styrene-butadiene-        5       5       5     5     5styreneblock copolymer(Kraton 1101)polyethylene 1.5     1.5     1.5   1.5   1.5clay reinforcing agent        25      --      43    43    --(NCF, FreeportKaolin)PropertiesTensile yield        8,500   9,100   8,500 11,400                                    10,900Tensile strength        8,400   8,000   8,400 11,400                                    9,700at breakTensile elongation        39      52      24    71    60Izod impact  3.5     7.4     2.4   2.0   5.8Gardner impact        163     282     122   42    272Flexural modulus        457,000 312,000 547,000                              608,000                                    350,000Flexural strength        13,600  12,500  14,300                              18,000                                    14,700Heat Distortion Temp.        232     230     241   267   253______________________________________ *control 
    
     EXAMPLES 14-19 
     Blends of 78 parts of poly(2,6-dimethyl-1,4-phenylene ether) resin, 22 parts of triphenyl phosphate flame retardant plasticizer, 1.5 parts of polyethylene, 0.5 parts of tridecyl phosphite, 0.15 parts of zinc sulfide, 0.15 parts of zinc oxide, 43 parts of a clay reinforcing filler (NCF, Freeport Kaolin) and various impact modifiers and amounts, as shown, are compounded, extruded and molded as in Examples 1-4. The physical properties are summarized in Table 4. 
     
                                           TABLE 4__________________________________________________________________________             Tensile     Impact  FlexuralExampleImpact Modifier             Yield                 Break                     Elong.                         Izod                            Gardner                                 Mod.                                     Str.__________________________________________________________________________14   5 parts styrene-butadiene-             10,500                 9,600                     49  1.8                            203  583,000                                     16,000styrene block copolymer.sup.e15   10 parts styrene-butadiene-              9,800                 9,200                     51  2.7                            212  538,000                                     14,700styrene block copolymer.sup.e16   5 parts styrene-butadiene-             10,600                 10,200                     50  2.0                            185  580,000                                     14,500styrene block copolymer.sup.e17   5 parts hydrogenated sty-              9,000                 8,800                     33  2.4                            190  515,000                                     13,600rene-butadiene-styreneblock copolymer.sup.f18   5 parts acrylic-styrene-             10,500                 9,600                     46  1.3                            195  593,000                                     15,100styrene-butadiene terpoly-mer.sup.g19   5 parts graft copolymer             10,400                 9,600                     49  1.3                            195  615,000                                     15,300of styrene and styrene-butadien.sup.h__________________________________________________________________________ .sup.e K1101, Shell Chem. Co., Polymers Div. .sup.f KG 6521, Shell Chem. Co., Polymers Div. .sup.g Acryloid KM 611, Rohm &amp; Haas Co. .sup.h Blendox 525, Marbon Chem. Co. 
    
     EXAMPLES 20-38 
     Blends of 78 parts of poly(2,6-dimethyl-1,4-phenylene ether), 22 parts of triphenyl phosphate, 5 parts of acrylic-styrene-styrene-butadiene terpolymer (Acryloid KM 611, Rohm &amp; Haas Co.), 1.5 parts of polyethylene, 0.5 parts of tridecyl phosphite, 0.15 parts of zinc sulfide, 0.15 parts of zinc oxide and 43 parts of various mineral reinforcing agents are compounded, extruded and molded as in Examples 1-4. The mineral reinforcements and tests results are summarized in Tables 5, 5A and 5B. 
     
                                           TABLE 5__________________________________________________________________________          Tensile     Impact   Flexural                                       UL-94ExampleFiller    Yield              Break                  Elong.                      Izod                         Gardner                               Mod.                                   Str.                                       Flame Test__________________________________________________________________________20   Calcium carbonate.sup.i           9,400              7,800                  16  0.9                         less than 10                               451,000                                   14,200                                       1.2/2021   Calcium carbonate.sup.j           9,500              7,600                  21  1.0                          10   461,000                                   14,800                                       1/2.322   Antimony Oxide           8,500              8,100                  76  7.4                         240   350,000                                   12,100                                       1.3/5.323   Clay.sup.k          10,100              9,100                  29  1.6                         150   516,000                                   14,900                                       1.7/4.724   Clay.sup.l          10,100              8,600                  25  1.0                         less than 10                               578,000                                   15,000                                       1.7/225   Clay.sup.m          10,200              8,900                  34  1.1                         140   560,000                                   15,200                                       1/326   Clay.sup.n          11,000              9,300                  36  1.4                         260   642,000                                   16,000                                       1.3/2  26A*NONE       9,300              8,800                  90  20.4                         300   317,000                                   12,800                                       1.7/3__________________________________________________________________________ *control .sup.i Carbium, Diamond Shamrock Co., precipitated calcium carbonate .sup.j Carbium MM, Diamond Shamrock Co., precipitated calcium carbonate .sup.k Al--Sil--Ate W, Freeport Kaolin Co. .sup.l Al--Sil--Ate LO, Freeport Kaolin Co. .sup.m Al--Sil--Ate HO2, Freeport Kaolin Co. .sup.n Al--Sil--Ate NC, Freeport Kaolin Co. 
    
     
                       TABLE 5A______________________________________      Tensile       ImpactExample  Filler    Yield   Break Elong.                                Izod Gardner______________________________________27     Barium    9,300   8,000 61    1.5  83  sulfate.sup.m28     Calcium   8,800   7,100 23    1.2  10  carbonate.sup.n29     Calcium   8,900   7,200 25    1.3  75  carbonate.sup.o30     Calcium   9,000   7,100 25    1.2  31  carbonate.sup.p31     Calcium   9,100   7,200 28    1.3  52  carbonate.sup.q  31A* NONE      9,200   9,200 86    3.3  202______________________________________ *control .sup.m #1 Barytes, Charles Pfizer Co. .sup.n Marblewhite 325, Charles Pfizer Co., a pulverized natural calcium carbonate .sup.o Vicron 1515, Charles Pfizer Co., a ground natural calcium carbonat .sup.p Vicron 2511, Charles Pfizer Co., ground natural calcium carbonate .sup.q Vicron 418, Charles Pfizer Co., ground natural calcium carbonate 
    
     
                                           TABLE 5B__________________________________________________________________________          Tensile     Impact  FlexuralExampleFiller    Yield              Break                  Elong.                      Izod                         Gardner                              Mod.                                  Str.__________________________________________________________________________32   Clay.sup.r          9,500              7,600                  45  1.2                         52   565,000                                  14,100                         less than33   Calcium carbonate.sup.s          8,000              6,700                  50  1.0                         10   382,000                                  12,00034   Talc.sup.t          9,800              7,500                  24  1.1                         10   654,000                                  14,60035   Talc.sup.u          9,200              9,200                  17  1.0                         10   593,000                                  13,80036   Talc.sup.v          9,700              9,700                  22  1.1                         40   650,000                                  14,60037   Talc.sup.w          10,200              8,600                  22  1.2                         60   674,000                                  14,700  37A*NONE      7,800              7,700                  102 2.6                         293  283,000                                  10,950__________________________________________________________________________ *control .sup.r Al--Sil--Ate NC, Freeport Kaolin Co. .sup.s Winnofil 5, ICI Co. .sup.t Emtal 596, Englehard Co. .sup.u MP 4526, Charles Pfizer Co. .sup.v MP 2538, Charles Pfizer Co. .sup.w MP 1250, Charles Pfizer Co. 
    
     EXAMPLES 38-43 
     Molded compositions of poly(2,6-dimethyl-1,4-phenylene ether) resin, triphenyl phosphate and various mineral reinforcing agents, as shown, are prepared as in Examples 1-4 and evaluated for physical properties. The formulations and physical properties are summarized in Tables 6 and 6A, respectively. 
     
                       TABLE 6______________________________________         EXAMPLEIngredients (parts by weight)           38     39    40    41  42    43______________________________________poly(2,6-dimethyl-1,4-           55     55    55    63  63    63phenylene ether)triphenyl phosphate           15     15    15    17  17    17clay            30     --    --    20  --    --titanim dioxide --     30    --    --  20    --zinc oxide      --     --    30    --  --    20______________________________________ 
    
     
                                           TABLE 6A__________________________________________________________________________Tensile          Impact  FlexuralExampleYield    Break        Elong.            Izod               Gardner                    Mod.                        Str.                            Gloss                                Melt Viscosity__________________________________________________________________________38   10,900    8,700        33  0.9                10  582,000                        16,900                            40.5                                1,95039   10,200    8,700        63  0.9               110  438,000                        16,000                            --  2,15040   10,300    8,600        71  0.8               100  410,000                        15,900                            65  1,98041   10,800    9,100        75  1.0               123  485,000                        16,300                            52.5                                2,05042   10,000    8,600        73  0.9               100  397,000                        15,700                            --  2,25043   10,200    8,500        68  1.0               110  390,000                        15,800                            64,7                                2,300__________________________________________________________________________ 
    
     EXAMPLES 44-48 
     Molded compositions of poly(2,6-dimethyl-1,4-phenylene ether), triphenyl phosphate, mineral reinforcing agents and impact modifiers are prepared as in Examples 1-4. The formulations and physical properties are shown in Tables 7 and 7A, respectively. 
     
                       TABLE 7______________________________________         EXAMPLEIngredients (parts by weight)           44       45    46    47  48______________________________________poly(2,6-dimethyl-1,4-           55       55    55    47  39phenylene ether)triphenyl phosphate           15       15    15    13  11clay            30       --    --    --  --titanium dioxide           --       30    30    40  50styrene/styrene-buta-            5        5    --     5   5diene copolymer (Blen-dex 525, Marbon Chem.Co.)acrylic resin modified           --       --     5    --  --styrene-butadiene co-polymer (Acryloid KM611, Rohm &amp; Haas Co.)______________________________________ 
    
     
                                           TABLE 7A__________________________________________________________________________Tensile          Impact  Flexural    Heat Deflection                                        UL-94ExampleYield    Break        Elong.            Izod               Gardner                    Mod.                        Str.                            Gloss                                Temp.   Flame Test__________________________________________________________________________44   9,600    8,200        45  1.7               183  546,000                        14,300                            41.0                                209     V-O45   8,900    8,900        80  7.0               232  363,000                        12,700                            60.5                                206     V-O46   8,900    9,100        83  7.5               242  351,000                        12,800                            60.5                                --      V-O47   8,700    8,300        55  4.8               222  396,000                        13,250                            57.5                                206     V-O48   8,700    8,200        42  3.9               183  468,000                        13,500                            50.5                                202     V-O__________________________________________________________________________ 
    
     EXAMPLES 49-50 
     Blends of poly(2,6-dimethyl-1,4-phenylene ether) resin, triphenyl phosphate, clay (NCF, Freeport Kaolin), a styrene-butadiene-styrene block copolymer (Kraton 1101), polyethylene, tridecyl phosphite, zinc sulfide and zinc oxide are compounded, extruded and molded as in Examples 1-4. The molded compositions are evaluated for physical properties, initially, after heat aging and after water immersion. The formulations and test results are summarized in Tables 8, 8A, 8B and 8C. 
     
                       TABLE 8______________________________________              EXAMPLEIngredients (parts by weight)                49     50______________________________________poly(2,6-dimethyl-1,4-                55     67phenylene ether)triphenyl phosphate  15     13styrene-butadiene-styrene                5      5block copolymer (Kraton1101)clay                 30     20polyethylene         1.5    1.5tridecyl phosphate   0.5    0.5zinc sulfide         0.15   0.15zinc oxide           0.15   0.15______________________________________ 
    
     
                       TABLE 8A______________________________________Initial Physical Properties             EXAMPLEProperties          49      50______________________________________Tensile yield, psi 73° F.      9,360   9,120150° F.      6,770   6,370Elongation, % 73° F.      41      68150° F.      39      58Flexural Strength, psi 73° F.      13,900  12,700150° F.      8,400   8,200Flexural Modulus, psi 73° F.      558,900 419,600150° F.      446,000 353,000Notched Izod impact,ft. lbs./in. 73° F.      3.3     8.6-40° F.      0.8     1.1Gardner impact, in. lbs. 73° F.      83      252-40° F.      10      45______________________________________ 
    
     
                                           TABLE 8B__________________________________________________________________________Physical Properties After Heat Aging at 65° C. and 115° C.at 65° C.   at 115° C.Tensile            TensileNo. of             No. ofDays    Yield   Break      Elong.          Impact              Days                  Yield                      Break                          Elong.                              Impact__________________________________________________________________________Example 490    9,400   8,400      41  45.3              0    9,400                       8,400                          41  45.31    9,500   8,100      34  41.5              1    9,900                       7,800                          31  34.310  10,000   8,300      32  42.5              10  --  --  --  30.030  10,100   8,700      37  46.9              20  10,800                       9,700                          18  27.659  10,700   9,000      29  39.3              30  11,800                      11,800                          16  24.290  11,000   9,100      32  44.3              59  12,000                      12,000                           8  23.3180 11,700   9,600      25  32.0              90  11,900                      11,900                           8  23.4Example 500    9,100   8,700      68  63.7              0    9,100                       8,700                          68  63.71    9,600   8,600      60  61.0              1   10,000                       8,100                          41  48.310   9,800   8,400      52  60.7              10  --  --  --  39.230   9,700   8,000      54  62.1              20  11,200                       8,500                          22  35.859   9,900   8,300      34  59.4              30  11,600                      10,200                          29  28.290  10,600   9,100      50  57.0              59  12,300                       9,900                          19  21.8180 11,100   9,500      45  58.8              90  12,900                      12,900                          13  25.7__________________________________________________________________________ 
    
     
                       TABLE 8C______________________________________Physical Properties After Immersing in Water at 200° F.Tensile                               IzodNo. of Days Yield   Break     Elong.                               Impact______________________________________Example 49 0          9,400   8,400     41    3.310          9,100   7,900     40    3.120          9,100   7,700     31    3.030          9,300   7,800     31    3.540          9,600   8,300     27    3.650          9,500   8,300     24    3.559          9,900   8,400     23    3.590          10,000  7,900     27    3.2Example 50 0          9,100   8,700     68    8.610          9,100   8,500     88    3.920          9,500   8,000     40    3.830          9,600   8,100     59    4.140          9,800   8,200     56    4.350          10,100  8,300     40    3.859          10,200  8,300     28    3.790          10,700  8,700     23    3.3______________________________________ 
    
     Obviously, other modifications and variations of the present invention are possible in the light of the above teachings. It is therefore, to be understood that changes may be made in the particular embodiments described above which are within the full intended scope of the invention as defined in the appended claims.