POLYIMIDE RESIN COMPOSITION

Abstract: This invention relates to molding resin compositions, and more particularly relates to polyimide resin compositions having markedly improved molding ability in addition to excellent high temperature stability, chemical resistance and mechanical strength. The polyimide resin compositions of this invention comprises 99.9 to 50.0% by weight of the polyimide and 0.1 to 50.0% by weight of polyphenylene sulfide and/or aromatic polysulfone and/or aromatic polyetherimide high-temperature engineering polymer. The polyimide consists essentially of recurring units of the following formula:

Description: The present invention relates to a molding resin composition, and more particularly relates to a molding resin composition of polyimide which is excellent in high-temperature stability, chemical resistance and mechanical strength as well as processing ability in molding. Polyimide has so far been excellent in mechanical strength, dimensional stability, high-temperature stability, flame retardance and electrical insulative properties. Therefore polyimide has been used in the field of electric and electronic parts, aeronautics and space instruments and transport machinery. It is also expected to be widely used in the future in the field where high-temperature resistance is required. A variety of polyimides which exhibit outstanding properties have been developed. Some polyimides, however, have no distinct glass transition temperature, although they are excellent in high-temperature stability. As a result, when employed as molding materials, specific methods such as sinter molding must be used for processing. Other polyimides which are excellent in processability have low glass transition temperatures and are soluble in halogenated hydrocarbons, which renders these polyimides unsatisfactory for use in applications which require high-temperature stability and solvent resistance. Thus, these polyimides have numerous advantages and disadvantages. Accordingly a polyimide has been desired which is excellent in high-temperature stability and solvent resistance and also has an outstanding processability as a molding material. The present inventors have found a polyimide which satisfies the aforementioned proparties. The polyimide has recurring units of the formula: wherein X is a divalent radical selected from radicals having the formulae: and and R is a tetravalent radical selected from aliphatic radicals having 2 or more carbon atoms, alicyclic radicals, monocyclic aromatic radicals, fused polycyclic aromatic radicals, and polycyclic aromatic radicals wherein in the aromatic radicals are linked to one another by a direct bond or via a bridging group. This polyimide is disclosed by Mitsui Toatsu Chemicals, Inc. in Japanese Laid-Open Patent Nos. TOKKAISHO 63-243132 (1988), 64-9226 (1989) and 64-9227 (1989). The above polyimide is a thermoplastic polyimide having fluidity at high temperatures in addition to excellent mechanical, thermal and electrical properties. A polyimide having recutting units of the above formula wherein X represents is also disclosed in EP-A-0 297 808, a document relevant under Art. 54(3) EPC. This EP-document also discloses high-temperature resistant adhesives comprising this polyimide. Compared to ordinary engineering polymers represented by polyethylene terephthalate, polybutylene terephthalate, polysulfone and polyphenylene sulfide, polyimide is superior in high-temperature resistance and other properties. On the other hand, the processability of the polyimide is still inferior to these polymers. Generally, in injection molding or extrusion molding, a lower melt viscosity leads to better processing ability. For example, a higher melt viscosity requires a higher injection pressure in the molding stage and the molded products are subject to excessive stress, thereby lowering operation efficiency and causing adverse effects on the properties of the molded products. The above stated polyimide can be injection molded because it has an excellent fluidity at high temperatures. Nevertheless it is desirable to enhance further the workability of the polyimide. The object of this invention is to provide a molding resin composition of polyimide which has very excellent melt flowability without adverse affects on the essential properties of polyimide. The present invention provides a polyimide resin composition comprising as a first component, 99.9 to 50.0% by weight of polyimide which has recurring units of the formula: wherein X is a divalent radical selected from radicals having the formulae: and and R is a tetravalent radical selected from aliphatic radicals having 2 or more carbon atoms, alicyclic radicals, monocyclic aromatic radicals, fused polycyclic aromatic radicals, and polycyclic aromatic radicals wherein the aromatic radicals are linked to one another by a direct bond or via a bridging group and, as a second component, 0.1 to 50.0% by weight of high-temperature engineering polymer selected from polyphenylene sulfide, aromatic polysulfones and aromatic polyetherimides different from the first component. The polyimide used in this invention is derived from a diamine of the following formula: where X is the same as above. The diamine is bis[4-(3-(4-aminophenoxy)benzoyl)phenyl]ether or bis[4-(4-(4-aminophenoxy)phenoxy)phenyl]sulfone. These diamines have the following formulae respectively: and The diamine is reacted with at least one tetracarboxylic dianhydride in an organic solvent to yield polyamic acid. The polyamic acid is imidized to obtain polyimide. The tetracarboxylic dianhydride used in the above reaction is an anhydride of the formula: where R is the same as above. The tetracarboxylic dianhydrides that can be used include, for example, ethylenetetracarboxylic dianhydride, butanetetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, pyromellitic dianhydride, 3,3′,4,4′-benzophenonetetracarboxylic dianhydride, 2,2′,3,3′-benzophenonetetracarboxylic dianhydride, 3,3′,4,4′-biphenyltetracarboxylic dianhydride, 2,2′3,3′-biphenyltetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 2,2-bis(2,3-dicarboxyphenyl)propane dianhydride, bis(3,4-dicarboxyphenyl) ether dianhydride, bis(2,3-dicarboxyphenyl) ether dianhydride, bis(3,4-dicarboxyphenyl) sulfone dianhydride, 1,1-bis-(2,3-dicarboxyphenyl)ethane dianhydride, bis(2,3-dicarboxyphenyl)methane dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, 4,4′-(p-phenylenedioxy)diphthalic dianhydride, 4,4′-(m-phenylenedioxy)diphthalic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 1,2,3,4-benzenetetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, 2,3,6,7-anthracenetetracarboxylic dianhydride and 1,2,7,8-phenanthrenetetracarboxylic dianhydride. Particularly preferred tetracarboxylic dianhydrides are pyromellitic dianhydride, 3,3′,4,4′-biphenyltetracarboxylic dianhydride, 3,3′,4,4′-benzophenonetetracarboxylic dianhydride, bis(3,4-dicarboxyphenyl) ether dianhydride and 4,4′-(p-phenylenedioxy)diphthalic dianhydride. The tetracarboxylic dianhydride can be used singly or in mixtures of two or more. The polyimide in the composition of this invention is prepared by using the above stated diamine as a raw material. Other diamines can also be used in combination with the above diamine within the range which has no adverse effect on the advantageous properties of the polyimide. Examples of diamines which may be used in admixture with the above diamine include, m-phenylenediamine, o-phenylenediamine, p-phenylenediamine, m-aminobenzylamine, p-aminobenzylamine, bis(3-aminophenyl) ether, (3-aminophenyl) (4-aminophenyl) ether, bis(4-aminophenyl) ether, bis(3-aminophenyl) sulfide, (3-aminophenyl) (4-aminophenyl) sulfide, bis(4-aminophenyl) sulfide, bis(3-aminophenyl) sulfoxide, (3-aminophenyl) (4-aminophenyl) sulfoxide, bis(4-aminophenyl) sulfoxide, bis(3-aminophenyl) sulfone, (3-aminophenyl) (4-aminophenyl) sulfone, bis(4-aminophenyl) sulfone, 3,3′-diaminobenzophenone, 3,4′-diaminobenzophenone, 4,4′-diaminobenzophenone, bis[4-(3-aminophenoxy)phenyl]methane, bis [4-(4-aminophenoxy)phenyl]methane, 1,1-bis[4-(3-aminophenoxy)phenyl]ethane, 1,1-bis[4-(4-aminophenoxy)phenyl]ethane, 1,2-bis[4-(3-aminophenoxy)phenyl]ethane, 1,2-bis[4-(4-aminophenoxy)phenyl]ethane, 2,2-bis[4-(3-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(3-aminophenoxy)phenyl]butane, 2,2-bis[4-(4-aminophenoxy)phenyl]butane, 2,2-bis[4-(3-aminophenoxy)phenyl-1,1,1,3,3,3-hexafluoropropane, 2,2-bis[4-(4-aminophenoxy)phenyl-1,1,1,3,3,3-hexafluoropropane, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(3-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 4,4′-bis(3-aminophenoxy)biphenyl, 4,4′-bis(4-aminophenoxy)biphenyl, bis[4-(3-aminophenoxy)phenyl] ketone, bis[4-(4-aminophenoxy)phenyl] ketone, bis[4-(3-aminophenoxy)phenyl] sulfide, bis[4-(4-aminophenoxy)phenyl] sulfide, bis[4-(3-aminophenoxy)phenyl] sulfoxide, bis[4-(4-aminophenoxy)phenyl] sulfoxide, bis[4-(3-aminophenoxy)phenyl] sulfone, bis[4-(4-aminophenoxy)phenyl] sulfone, bis[4-(3-aminophenoxy)phenyl] ether and bis[4-(4-aminophenoxy)phenyl] ether. The high temperature engineering polymer (second component) which is used in the present invention is selected from polyphenylene sulfide, aromatic polysulfones and aromatic polyetherimides different from the first component. Polyphenylene sulfide is a resin having recurring units of the formula: The preparation process of the resin is disclosed, for example, by Phillips Petroleum Co. in U.S. Pat. 3,354,129 and Japanese Patent Publication TOKKOSHO 45-3368 (1970). The resin is commercially available, for example, as RYTON (Trade Mark of Phillips Petroleum Co. in U.S.A.). According to the patent disclosure, polyphenylene sulfide is produced by reacting p-chlorobenzene with sodium sulfide monohydrate at 160-250°C under pressure in N-methylpyrrolidone solvent. Polyphenylene sulfide includes various grades such as non-crosslinked or partially crosslinked polymers and polymers having different polymerization degrees. These grades can be easily produced by conducting a post-treatment process and are also available in the market. Therefore grades having suitable melt viscosity for the desired polymer blend can be optionally prepared or purchased in the market. Aromatic polysulfones are a well known high temperature engineering polymers having a polymer chain including units of the formula: and described, for example, by V.J. Leslie et al, in CHEMITECH, July 1975 , 426-432. Representative examples of recurring units constituting aromatic polysulfones include: Typical aromatic polysulfones include, for example, polysulfone consisting of recurring units represented by the formula: (Commercially available from Imperial Chemical Industries in Britain under the trademark VICTREX PES) and polysulfone consisting of recurring units represented by the formula: (Commercially available from Union Carbide Corp. in U.S.A. under the trademark UDEL POLYSULFONE). Different grades of aromatic polysulfone having various polymerization degrees can be easily produced. Therefore grades having a suitable melt viscosity for the desired polymer blend can be readily selected. Aromatic polyetherimide are polymers having both ether and imide linkages as a required bonding unit and substantially composed of recurring units of the following formula: wherein Z is a trivalent aromatic radical where two valences out of three are connected with two adjacent carbon atoms, and Y and Ar are respectively a divalent monocyclic aromatic radical and a divalent polycyclic aromatic radical in which the aromatic rings are connected by a bridging group. These polyetherimides are also well known high temperature engineering polymers and are described, for example, by Takekoshi et al. in Polymer Preprint 24 ,(2),312-313 (1983). Suitable examples of recurring units constituting aromatic polyetherimide of this invention include: Aromatic polyetherimides are commercially available from General Electric Co. in U.S.A. under the trademarks ULTEM-1000, ULTEM-4000 and ULTEM-6000 etc. Aromatic polyetherimide particularly consisting of recurring units of the formula: is commercially available from General Electric Co. under the trademark ULTEM-1000. Several grades of aromatic polyetherimide having various polymerization degrees can be easily produced. Therefore grades having suitable melt viscosity for the desired polymer blend can be readily selected. The resin molding composition of this invention is prepared so as to comprise the above mentioned polyimide in the range of 99.9 to 50.0% by weight and the high-temperature engineering polymer in the range of 0.1 to 50.0% by weight and may include in addition one or more of the common additives hereinafter mentioned. The resins of this invention based on polyimide/polyphenylene sulfide exhibit remarkably low melt viscosity in a high temperature region above 350°C. The advantageous effect on melt viscosity obtained by the polyphenylene sulfide can be found even in small amounts. The lower limit of the amount in the composition is 0.1% by weight. The preferred amount is not less than 0.5% by weight. Polyphenylene sulfide is excellent in chemical resistance, water absorption and flame retardance among the high-temperature stable resins. It is, however, inferior particularly in elongation at break and in impact resistance. Therefore, too much polyphenylene sulfide in the composition is undesirable because the essential mechanical strength of the polyimide cannot be maintained. The amount of polyphenylene sulfide in the composition has an upper limit and is 50.0% by weight or less. The resins of this invention based on polyimide/aromatic polysulfone exhibit remarkably low melt viscosity in a high temperature region such as above 380°C. The advantageous effect on melt viscosity obtained by the aromatic polysulfone can be found even in a small amount. Again, the lower limit of the amount in the composition is 0.1% by weight and the preferred amount is not less than 0.5% by weight. Aromatic polysulfones are excellent in mechanical strength at high temperatures. They are, however, inferior to polyimide in mechanical strength, and in izod impact strength in particular. Therefore, too much aromatic polysulfone in the composition is undesirable because the essential mechanical strength of the polyimide cannot be maintained. Again, the amount of aromatic polysulfone in the composition has an upper limit and is 50.0% by weight or less. The resins of this invention based on polyimide/aromatic polyetherimide also exhibit remarkably low melt viscosity, as compared with polyimide alone, in a high temperature region, above 350°C in particular. The effect can be found even with a small amount of aromatic polyetherimide. As before, the lower limit in the composition is 0.1% by weight and the preferred amount is not less than 0.5% by weight. Aromatic polyetherimides are excellent in mechanical strength at high temperatures. They are, however, inferior to the polyimide of the first component in mechanical strength, and in izod impact strength in particular. Therefore, too much aromatic polyetherimide is undesirable because the essential mechanical strength of the polyimide of the first component cannot be maintained. Aromatic polyetherimides are easily soluble in halogenated hydrocarbons such as methylene chloride and chloroform as well as amide type solvents such as dimethyl acetamide and N-methyl-pyrrolidone. Therefore, too much aromatic polyetherimide in the composition is also undesirable because the essential solvent resistance of the polyimide of the first component cannot be mainained. For these reasons, the amount of aromatic polyetherimide has an upper limit in the composition and is again 50.0% by weight or less. In the preparation of the composition of this invention, known methods can be employed and, for example, the below described methods are preferred. (1) Polyimide powder and high-temperature engineering polymer powder are pre-mixed to prepare a uniform mixture of powder by using a blender such as a mortar, Henshel mixer, drum blender, tumbler blender, ball mill or ribbon blender. (2) Polyimide powder is previously dissolved or suspended in an organic solvent. High-temperature engineering polymer is added to the resulting solution or suspension and dispersed or dissolved uniformly, followed by removing the solvent to give a powdered mixture. (3) High-temperature engineering polymer is suspended in an organic solvent solution of polyamic acid which is the precursor of the polyimide in this invention. The resultant suspension is imidized by heat treatment at 100-400°C or by chemical imidization with a usual imidizing agent, followed by removing the solvent to give a powdered mixture. The powdered resin composition of polyimide thus obtained can be used as it is for various molding applications such as injection molding, compression molding, transfer molding and extrusion molding. A more preferred method is fusion blending of the resins prior to molding. Fusion blending of polyimide and high-temperature engineering polymer in the forms of, respectively, powder and powder, pellet and pellet, or powder and pellet is a simple and effective method. Fusion blending can be carried out by using the fusion blending equipment usually employed for rubber and plastics, for example, hot rolls, Banbury mixer, Brabender and extruder. The operating temperature is set above the fusion temperature of the formulated system and below the initiation temperature of its decomposition. The temperature for blending polyimide with polyphenylene sulfide is normally in the range of 300-420°C and preferably in the range of 320-400°C. The blending of polyimide with an aromatic polysulfone or an aromatic polyetherimide is carried out normally in the range of 280-420°C and preferably in the range of 300-400°C. As to the method of molding the resin composition of this invention, injection and extrusion molding are suitable because these methods form uniform blend of fused polymers and have a high productivity. Other processing methods such as transfer molding, compression molding and sinter molding may also be employed. In addition, the resin composition of this invention may contain at least one solid lubricant such as molybdenum disulfide, graphite, boron nitride, lead monoxide and lead powder. The composition may also contain at least one reinforcing material such as glass fibers, carbon fibers, aromatic polyamide fibers, potassium titanate fibers and glass beads. The resin composition may further contain at least one commonly used additive within the range which has no adverse effect on the object of this invention. Such additives include, for example, antioxidants, heat stabilizers, ultraviolet absorbers, flame retardants, auxiliary flame retardants, antistatic agents, lubricants and coloring agents. EXAMPLES The present invention will hereinafter be illustrated further by way of detailed synthesis examples, composition examples and comparative examples. Synthesis Example 1 A reaction vessel equipped with a stirrer, reflux condenser and nitrogen inlet tube was charged with 5.92 kg (10 moles) of bis[4-(3-(4-aminophenoxy)benzoyl)phenyl] ether and 18.8 kg of N,N-dimethylacetamide. To the mixture was added 2.14 kg (9.8 moles) of pyromellitic dianhydride portion by portion in a nitrogen atmosphere at room temperature and at a rate to avoid a large temperature rise of the solution and the mixture was stirred for 24 hours at room temperature. To the resultant polyamic acid solution, 5.37 kg of N,N-dimethylacetamide was added, and then 4.08 kg (40 moles) of triethylamine and 6.03 kg (60 moles) of acetic anhydride were added dropwise in a nitrogen atmosphere at room temperature and the mixture further stirred for 24 hours at room temperature. The reaction mixture was poured into 250 l of water well stirred. The separated product was filtered, washed with methanol and dried at 150°C for 24 hours under reduced pressure to obtain 7.47 kg of pale yellow polyimide powder (about 98% yield). The inherent viscosity of the polyimide powder was 0.86 dl/g. The inherent viscosity was measured at 35°C after dissolving 0.5 g of the polyimide powder in 100 ml of a solvent (a mixture of p-chlorophenol and phenol in a ratio of 90:10 by weight) at elevated temperature and cooling the resulting solution. The polyimide powder had a glass transition temperature of 235°C in accordance with the DSC method. Synthesis Examples 2-5 The same procedures as in Synthesis Example 1 were carried out. However, the raw materials were changed. The diamines and tetracarboxylic dianhydrides were varied to obtain various polyimide powders. Table 1 gives the conditions for the synthesis of the polyimide resins, and the inherent viscosities and glass transition temperatures (Tg) thereof. Synthesis Example 6 A reaction vessel equipped with a stirrer, reflux condenser and nitrogen inlet tube was charged with 61.67 kg (100 moles) of bis[4-4-(4-aminophenoxy)phenoxy)phenyl] sulfone and 473.0 kg of N,N-dimethylacetamide. To the mixture was added 20.7 kg (95 moles) of pyromellitic dianhydride portion by portion in a nitrogen atmosphere at room temperature and at a rate to avoid a large temperature rise of the solution and the mixture stirred for 20 hours at room temperature. The inherent viscosity of the polyamic acid thus obtained was 0.56 dl/g. The inherent viscosity was measured at 35°C after dissolving 0.5 g of the polyamic acid in 100 ml of N,N-dimethylacetamide. To the resultant polyamic acid solution, 275 kg of N,N-dimethylacetamide was added, and then 40.4 kg (400 moles) of triethylamine and 61.2 kg (600 moles) of acetic anhydride were added dropwise in a nitrogen atmosphere at room temperature and the mixture stirred for 24 hours at room temperature. The reaction mixture was poured into 2,500 l of water well stirred. The separated product was filtered, washed with methanol and dried at 180°C for 5 hours under reduced pressure to obtain 77.2 kg of polyimide powder (about 98% yield). The polyimide powder had a glass transition temperature of 285°C and melting point of 420°C in accordance with the DSC method. Synthesis Examples 7-10 The same procedures as in Synthesis Example 6 were carried out, except various tetracarboxylic dianhydrides were used in place of pyromellitic dianhydride. The amounts of diamine and tetracarboxylic dianhydride were varied to obtain various polyimide powders. Table 2 gives the conditions for the synthesis of the polyimide resins, the inherent viscosities of the polyamic acids and the glass transition temperatures (Tg) of the polyimides. Composition Examples 1-3 The polyimide powder obtained in Synthesis Example 1 was dry blended with polyphenylene sulfide powder RYTON P-4 (a trademarked product of Phillips Petroleum Co.) in various compositions as given in Table 3. The mixture was kneaded by fusing at 320-340°C in a double screw extruder and extruded to obtain uniform pellets. The pellets thus obtained were injection molded with an Arburg injection molding machine (Type: All-round A-220 from Arburg Co.) at an injection temperature of 320-400°C and a mold temperature of 150°C. The physical and thermal properties of the molded product were measured and the results are given in Table 3. In Table 3, tensile strength and elongation at break, flexural strength and flexural modulus, izod impact strength, and heat distortion temperature were respectively measured in accordance with ASTM D-638, D-790, D-256 and D-648. In addition, Table 3 gives minimum injection pressure which indicates melt flowability. Comparative Example 1 The same procedures as in Composition Examples 1-3 were carried out except that a composition outside the scope of this invention was used. The physical and thermal properties of molded specimens were measured and the results are given in Table 3. Composition Examples 4-12 and Comparative examples 2-5 The procedures of Composition Examples 1-3 were repeated by using the polyimide powder obtained in Synthesis Examples 2-5 and polyphenylene sulfide powder RYTON P-4 to give uniformly blended pellets. The pellets were injection molded. Physical and thermal properties were measured on the molded specimens. The results on compositions both within and outside the scope of this invention are given in Table 4 as Examples 4-12 and Comparative Examples 2-5, respectively. Composition Examples 13-15 The polyimide powder obtained in Synthesis Example 1 was dry blended with aromatic polysulfone powder UDEL POLYSULFONE P-1700 (a trademarked product of Union Carbide Corp.) in various compositions as given in Table 5. The mixture was kneaded by fusing at 360-390°C in a double screw extruder and extruded to obtain uniform pellets. The pellets thus obtained were injection molded at an injection temperature of 360-390°C and a mold temperature of 170°C. The physical and thermal properties of the molded product were measured and the results are given in Table 5. The glass transition temperature was measured in accordance with the TMA penetration method. Comparative Example 6 The same procedure as in Composition Examples 13-15 was carried out except that a composition outside the scope of this invention was used. The physical and thermal properties of molded specimens were measured and the results are given in Table 5. Composition Examples 16-23 and Comparative Examples 7-10 The procedures of Composition Examples 13-15 were repeated except that the polyimide powders obtained in Synthesis Examples 2-5 and aromatic polysulfone UDEL POLYSULFONE P-1700 were used to give uniformly blended pellets. The pellets were injection molded. Physical and thermal properties were measured on the molded specimens. The results on examples both within and outside the scope of this invention are given in Table 6 as Examples 16-23 and Comparative Examples 7-10, respectively. Composition Examples 24-27 The polyimide powder obtained in Synthesis Example 1 was dry blended with aromatic polyetherimide ULTEM 1000 (a trademarked product of General Electric Co.) in various compositions as given in Table 7. The mixture was kneaded by fusing at 370-400°C in a double screw extruder and extruded to obtain uniform pellets. The pellets thus obtained were injection molded at an injection temperature of 360-390°C and a mold temperature of 150°C. The physical and thermal properties of the molded product were measured and the results are given in Table 7. Comparative Example 11 The same procedure as in Composition Examples 24-27 was carried out except that a composition outside the scope of this invention was used. The physical and thermal properties of molded specimens were measured and the results are given in Table 7. Composition Examples 28-35 and Comparative Examples 12-15 The procedures of Composition Examples 24-27 were repeated except that the polyimide powder obtained in Synthesis Examples 2-5 and aromatic polyetherimide ULTEM 1000 were used to give uniformly blended pellets. The pellets were injection molded. Physical and thermal properties were measured on the molded specimens. The results on examples both within and outside the scope of this invention are given in Table 8 as Examples 28-35 and Comparative examples 12-15, respectively. Composition Examples 36-38 The polyimide powder obtained in Synthesis Example 6 was dry blended with polyphenylene sulfide powder RYTON P-4 in various compositions as given in Table 9. The mixture was kneaded by fusing at 320-420°C in a double screw extruder and extruded to obtain uniform pellets. The pellets thus obtained were injection molded at an injection temperature of 320-420°C and a mold temperature of 150°C. The physical and thermal properties of the molded product were measured and the results are given in Table 9. Comparative Examples 16-17 The same procedures as Composition Examples 36-38 were carried out except that compositions outside the scope of this invention were used. The physical and thermal properties of molded specimens were measured and the results are given in Table 9. Composition Examples 39-47 and Comparative Examples 18-21 The procedures of Composition Examples 36-38 were repeated except that the polyimide powders obtained in Synthesis Examples 7-10 and polyphenylene sulfide powder RYTON P-4 were used to give uniformly blended pellets. The pellets were injection molded. Physical and thermal properties were measured on the molded specimens. The results on examples both within and outside the scope of this invention are given in Table 10 as Examples 39-47 and Comparative Examples 18-21, respectively. Composition Examples 48-50 The polyimide powder obtained in Synthesis Example 6 was dry blended with aromatic polysulfone UDEL POLYSULFONE P-1700 in various compositions as given in Table 11. The mixture was kneaded by fusing in a double screw extruder and extruded to obtain uniform pellets. The pellets thus obtained were injection molded at an injection temperature of 380-400°C and a mold temperature of 170°C. The physical and thermal properties of the molded product were measured and the results are given in Table 11. Comparative Example 22 The same procedure as in Composition Examples 48-50 were carried out except that a composition outside the scope of this invention was used. The physical and thermal properties of molded specimens were measured and the results are given in Table 11. Composition Examples 51-58 and Comparative Examples 23-26 The procedures of Composition Examples 48-50 were repeated except that the polyimide powder obtained in Synthesis Examples 7-10 and aromatic polysulfone VICTREX PES 3600P (a trademarked product of Imperial Chemical Industries) or aromatic polysulfone UDEL POLYSULFONE P-1700 were used to give uniformly blended pellets. The pellets were injection molded. Physical and thermal properties were measured on the molded specimens. The results on examples both within and outside the scope of this invention are given in Table 12 as Examples 51-58 and Comparative Examples 23-26, respectively. Composition Examples 59-62 The polyimide powder obtained in Synthesis Example 6 was dry blended with aromatic polyetherimide ULTEM 1000 in various compositions as given in Table 13. The mixture was kneaded by fusing at 350-370°C in a double screw extruder and extruded to obtain uniform pellets. The pellets thus obtained were injection molded at an injection temperature of 380-400°C and a mold temperature of 170°C. The physical and thermal properties of the molded product were measured and the results are given in Table 13. Comparative Example 27 The same procedure as in Composition Examples 59-62 was carried out except that a composition outside the scope of this invention was used. The physical and thermal properties of molded specimens were measured and the results are given in Table 13. Composition Examples 63-70 and Comparative Examples 28-31 The procedures of Composition Examples 59-62 were repeated except that the polyimide powders obtained in Synthesis Examples 7-10 and aromatic polyetherimide ULTEM 1000 were used to give uniformly blended pellets. The pellets were injection molded. Physical and thermal properties were measured on the molded specimens. The results on examples both within and outside the scope of this invention are given in Table 14 as Examples 63-70 and Comparative Examples 28-31, respectively.

Claims: A polyimide resin composition comprising, as a first component, 99.9 to 50.0% by weight of a polyimide which has recurring units of the formula: wherein X is a divalent radical selected from radicals having the formulae: and and R is a tetravalent radical selected from aliphatic radicals having 2 or more carbon atoms, alicyclic radicals, monocyclic aromatic radicals, fused polycyclic aromatic radicals, and polycyclic aromatic radicals wherein the aromatic rings are linked to one another by a direct bond or via a bridging group, and, as a second component, 0.1 to 50.0% by weight of a high-temperature engineering polymer selected from polyphenylene sulfide, aromatic polysulfones and aromatic polyetherimides different from the first component. The polyimide resin composition as claimed in claim 1, wherein X is a divalent radical having the formula: The polyimide resin composition as claimed in claim 1, wherein X is a divalent radical having the formula: The polyimide resin composition as claimed in any of claims 1 to 3, wherein R is a tetravalent radical selected from and The polyimide resin composition as claimed in any of claims 1 to 4, wherein the high-temperature engineering polymer is polyphenylene sulfide. The polyimide resin composition as claimed in any of claims 1 to 4, wherein the high-temperature engineering polymer is an aromatic polysulfone. The polyimide resin composition as claimed in any of claims 1 to 4, wherein the high-temperature engineering polymer is an aromatic polyetherimide different from said first component.

Inventors: IIYAMA, KATSUAKI, KAWASHIMA, SABURO, OHTA, MASAHIRO, OIKAWA, HIDEAKI, TAMAI, SHOJI, YAMAGUCHI, AKIHIRO
Applicants: MITSUI TOATSU CHEMICALS, INC.
Application year: 1989
Main classification: C08L79
IPC codes: C08L79