Abstract: Disclosed herein are free-standing, pinhole-free, ultrathin polyimide films having thicknesses of about 400 angstroms or less and a process to prepare them. The films find particular utility in separatory applications.

Abstract: A polyamide acid solution is disclosed, comprising a polyamide acid comprising as main components at least one recurring unit selected from the recurring units of the formulae (I) to (IV) and a recurring unit of formula (V), dissolved in an organic solvent comprising as a main component an amide type polar solvent having a boiling point of 170.degree. C. or less. The solution is capable of forming a polyimide film which has colorless transparency free from coloration and strong adhesion to a substrate for liquid crystal cell enough to prevent penetration of water into interface between the substrate and film. The solution is particularly useful for forming a liquid crystal oriented film.

Abstract: A colorless transparent polyimide shaped article having as a main component at least one recurring unit selected from the recurring units of the formulae (I) to (IX). It is useful, for example, as an oriented film in liquid crystal display devices. The polyimide shaped article is produced by a process which comprises preparing a solution of a polyamide acid having as a main component at least one recurring unit selected from the recurring units of the formulae (V) to (VIII) in an amide-type organic polar solvent, forming a shaped article of the polyamide acid from the solution, and imidizing the resulting shaped article of the polyamide acid.

Abstract: Partially soluble, film-forming polyimides and their copolymers made using 3,5-diaminobenzotrifluoride are described. Thin films and coatings of these materials are relatively colorless and the polymers have a high Tg, excellent thermal stability, lower moisture uptake, and lower dielectric constant. They are useful as films, fibers, molded articles and as protective coatings, interlevel dielectrics, electric circuit substrates and the like for the electronics industry.

Abstract: Polyetherimide precursor compositions are prepared by a reacting mixture of at least two diamines selected from the group consisting of o-phenylenediamine, m-phenylenediamine and 4-aminophenyl ether with the esterification product of a low molecular weight alkanol such as methanol and an ether tetracarboxylic acid dianhydride, preferably 3,4-dicarboxyphenyl ether dianhydride. Said polyimide precursor compositions may be converted to polyimides useful in composite formation, by gently heating to remove excess alkanol and subsequently baking at temperatures in the range of about 275.degree.-375.degree. C.

Abstract: A colorless transparent polyimide shaped article having as a main component at least one recurring unit selected from the recurring units of the formulae (I) to (III), which is useful, for example, as an oriented film in liquid crystal display devices. The polyimide shaped article is produced by a process which comprises preparing a solution of (A) a polyimide precursor obtained by reacting a diamino compound comprising as a main component at least one aromatic diamine having amino groups at the m-position selected from diamines of formulae (IV) to (VI) with a tetracarboxylic acid compound comprising as a main component a tetracarboxylic acid dianhydride of formula (VII) dissolved in (B) at least one organic polar solvent selected from N,N-dimethylacetamide, N,N-dimethylformamide, bis(2-methoxyethyl)ether, cresol and halogenated phenols; forming a shaped article of the polyimide precursor from the solution; and imidizing the resulting shaped article.

Abstract: Described are flexible polyimide foams having enhanced compression characteristics and softness for use in the manufacture of seat cushions and methods for the production of such foams and precursors therefor. These foams are produced from novel polyimides prepared by reaction of at least one aromatic or heterocyclic primary diamine with a mixture of at least two organic tetracarboxylic acids or derivatives thereof, at least one of which is from 1 to 40 mol percent of a 2-(vicinal-dicarboxycyclohexenyl)succinic acid or derivative thereof and a second of which is an aromatic tetracarboxylic acid or derivative thereof.

Abstract: A method is provided for making 9,10-dithiaanthracene-2,3,6,7-tetracarboxylic acid dianhydride. Polyimides having improved oxidative stability also are provided which can be made intercondensing organic diamine and the aforementioned dianhydride or a dianhydride mixture.

Abstract: A photosensitive polyimide precursor composed of the structural units (A) represented by the following general formula (I) and the structural units (B) represented by the following general formula (II), in which the ratio of the molar quantity of the structural units (A) to the sum of the molar quantity of the structural units (A) and that of the structural units (B) is 0.01 or greater, and having a viscosity of 100 cP or above as measured at 25.degree. C. in the state of a 10% by weight solution in N-methylpyrrolidone: ##STR1## wherein R.sub.1 represents a tetravalent aromatic hydrocarbon residue; R.sub.2 represents a divalent aromatic hydrocarbon residue; X, identical or different represents a halogen or an alkyl group; and m represents 0 or an integer from 1 to 4. The photosensitivity of the present photosensitive polyimide precursor is about 20 to 100 times that of conventional products. After heat dehydration cyclization, it shows a heat resistance of 400.degree. C. or above.

Abstract: A novel co-poly (imide ether) copolymer consisting essentially of an organic acid dianhydride, a diamine, and a diaminated polyether, wherein the percentage of the diaminated polyether in the total amount of the diamine and the diaminated polyether is 5 to 40% by weight.

Abstract: Polyetherimides are prepared from at least two diamines selected from the group consisting of o-phenylenediamine, m-phenylenediamine and 4-aminophenyl ether and a dicarboxyphenyl ether anhydride, or the esterification product thereof with a low molecular weight alkanol such as methanol. 3,4-Dicarboxyphenyl ether dianhydride is preferred. Said polyimides are tough, flexible and stable at high temperatures.

Abstract: Described are flexible polyimide foams having enhanced compression characteristics and softness for use in the manufacture of seat cushions and methods for the production of such foams and precursors therefor. These foams are produced from novel polyimides prepared by reaction of at least one aromatic or heterocyclic primary diamine with a mixture of at least two organic tetracarboxylic acids or derivatives thereof, at least one of which is from 1 to 40 mol percent of a 2-(vicinal-dicarboxycyclohexenyl)succinic acid or derivative thereof and a second of which is an aromatic tetracarboxylic acid or derivative thereof.

Abstract: There are disclosed a process for producing a polyamide acid having at least one siloxane bond, which comprises carrying out the reaction of:(a) a tetracarboxylic dianhydride having at least one siloxane bond of the formula: ##STR1## wherein R represents a monovalent hydrocarbon group and m is an integer of 1 or more;(b) a diamine; and(c) a diaminoamide compound of the formula (II): ##STR2## wherein Ar represents an aromatic residue, Y represents SO.sub.2 or CO, and one amino group and Y--YNH.sub.

Abstract: Polyamide-imides of low thermal expansivity having a repeating structural unit of the general formula (I) ##STR1## in which Ar is a tetravalent aromatic group, A is --NHCO--, R1 through R3 are alkyl, alkoxy, or halogen, l, m, and n are integers from 0 to 4, x is 0 or 1, and y is an integer indicating the number of repeating units and in which at least one alkoxy group is present, show improved mechanical (for example, flexibility) and adhesive properties and low water absorption and are useful for the manufacture of flexible base materials for printed circuit boards, etc.

Abstract: Compounds containing at least 5 mol % of structural units of the formulae I and/or II ##STR1## in which Q is an unsubstituted or substituted tetravalent aromatic radical to which in each case two carbonyl groups are bonded in the ortho- or peri-position, R.sup.1 is selected from the radicals of the formulae III, IV and V ##STR2## R.sup.2, R.sup.3, R.sup.4 and R.sup.5 are hydrogen, alkyl, cycloalkyl or substituted or unsubstituted aryl or aralkyl, R.sup.6 and R.sup.7 are aryl or halogen, m and n are 0, 1 or 2 and o is 0, 1, 2, 3 or 4, are described.The compounds are distinguished by an increased resistance to oxidation by heat. They can be used to produce coatings and relief structures.

Abstract: A condensation polyimide containing a 1,1,1-triaryl-2,2,2-trifluoroethane structure, other related condensation polyimides and process for their preparation, which comprises polymerization of a cyclic dianhydride with a diamine.

Abstract: A thin film comprising a polymer having linear recurring units wherein an organic group R.sup.1 is combined alternately with an organic group R.sup.2 through a bivalent bonding group, wherein each of said group R.sup.1 and said group R.sup.2 has a valence of at least 2 and has at least 2 carbon atoms; each of said linear recurring units having at least one hydrocarbon-containing group R.sup.3 having 10 to 30 carbon atoms bonded with covalent bond, and a device having the thin film. The thin film of the invention is formed by building-up layers of the above polymer by LB technique, and the obtained film can be subjected to ring closure and to elimination of a known LB compound added as occasion demand by heat treatment to provide a thin film having a thickness of not more than 10,000 .ANG. and excellent heat resistance, chemical resistance and mechanical properties, and the device having the thin film is useful particularly as electric and electronic devices.

Abstract: Cyclic imides are prepared by the reaction of a bis(dicarboxyphenyl) sulfide or functional derivative thereof, and optionally a second tetracarboxylic acid or functional derivative thereof such as 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, with a diamine having a spirobiindane nucleus. The cyclic imides may be converted to linear polyimides by reaction with a basic alkali metal sulfide.

Abstract: Novel copolyimides are prepared by reacting one or more aromatic dianhydrides with a meta-substituted phenylene diamine and an aromatic bridged diamine. The incorporation of meta-substituted phenylene diamine derived units and bridged aromatic diamine derived units into the linear aromatic polymer backbone results in a copolyimide of improved flexibility, processability, and melt-flow characteristics. The novel copolyimides are especially useful as thermoplastic hot-melt adhesives.

Abstract: Described are flexible polyimide foams having enhanced compression characteristics and softness for use in the manufacture of seat cushions and methods for the production of such foams and precursors therefor. These foams are produced from novel polyimides prepared by reaction of at least one aromatic or heterocyclic primary diamine with a mixture of at least two organic tetracarboxylic acids or derivatives thereof, at least one of which is from 1 to 40 mol percent of a 2-(vicinal-dicarboxycyclohexenyl)succinic acid or derivative thereof and a second of which is an aromatic tetracarboxylic acid or derivative thereof.

Abstract: An amphiphilic polyimide precursor having at least 70% by mole of the recurring unit of the formula (1): ##STR1## wherein R.sup.1 is a tetravalent group having at least 2 carbon atoms, R.sup.2 is a bivalent group having at least 2 carbon atoms, and R.sup.3, R.sup.4, R.sup.5 and R.sup.6 are hydrogen atom or a monovalent group having 1 to 30 carbon atoms selected from an aliphatic group, an alicyclic group, an aromatic group, a group in which an aliphatic group is combined with an alicyclic group or an aromatic group, and their groups substituted by a halogen atom, nitro group, amino group, cyano group, methoxy group or acetoxyl group, provided that at least one, preferably at least two, of R.sup.3, R.sup.4, R.sup.5 and R.sup.

Abstract: The present invention provides a polyimide film whose residual content of volatiles is reduced to not more than 0.45 weight % on the basis of the film, and further a polyimide film whose residual content of volatiles is reduced to not more than 0.45 weight % on the basis of the film and whose oxygen/carbon ratio in the surface layer is increased by 0.01-0.1, and manufacturing methods therefor.According to the present invention, it is possible to provide a polyimide film improved in adhesion performance in a stable and homogeneous manner, and this improvement of adhesion performance is attainable in the film-forming process, not in a separate process of after-treatment.

Abstract: A method is provided for making organobis(thioether)s which include bis(thioetherimide)s and bis(thioetheranhydride)s. There is also provided alkylene bis(thioetherimide)s and the corresponding dianhydrides thereof which can be used to make crystalline polyimides.

Abstract: A process for forming a built-up film with logic polymers whose film inherently cannot be readily obtained by LB technique comprises modifying the high polymers, and if required, further cyclizing the product partially or wholly. The produced thin films have extremely excellent heat resistance, good chemical resistance and mechanical characteristics and their thickness is so small that it is generally hardly attainable, that is, less than 10,000 .ANG., or if desired, 10 to 1000 .ANG..

Abstract: Fully aromatic thermotropic polyesters based on(A) from 30 to 60 mol % of 4-hydroxybenzoic acid,(B) from 20 to 35 mol % of a mixture of(B.sub.1) terephthalic acid,(B.sub.2) isophthalic acid and(B.sub.3) from 0.5 to 5 mol % of a dicarboxylic acid of the general formula I ##STR1## where X is --O--, --S--, --SO.sub.2 --, --CO--, --CH.sub.2 -- or --C(CH.sub.3).sub.2 --, n is 0 or 1 and the two imide nitrogen atoms are meta or para to X, or their C.sub.1 -C.sub.8 -alkyl, C.sub.1 -C.sub.8 -alkoxy, aryl, chlorine or bromine derivatives which are substituted in the nucleus,the molar ratio of B.sub.1 to B.sub.2 being from 1.04:1 to 19:1, and(C) from 20 to 35 mol % of a mixture of(C.sub.1) hydroquinone and(C.sub.2) 4,4'-dihydroxydiphenyl,the molar ratio of C.sub.1 to C.sub.2 being from 0.1:1 to 2.67:1 and the molar ratio of B to C being from 0.9:1 to 1.1:1.

Abstract: High temperature fluorinated polyimides having repeating polymer units comprising ##STR1## wherein X is diamine. Typically, these polyimides are the copolymerization product of about 3 mole % to about 42 mole % nadic esters; about 39 mole % to about 49 mole % diamine; and about 17 mole % to about 48 mole % 4,4'9(2,2,2-trifluoro-1-phenylethylidene)-bipthalic tetra carboxylic acid dialkylester. These polimides provide the high strength properties at high temperatures yet they can be processed into solid polymers, fibers, films and composites at low temperatures and pressures.

Abstract: This invention relates to a novel polyimide and describes method of its preparation, adhesives of the polyimide and the method for their application.The polyimide has recurring units of the formula ##STR1## (where R is a tetra-valent radical selected from the group consisting of aliphatic radical having not less than two carbons, cyclo-aliphatic radical, monoaromatic radical, condensed polyaromatic radical, and non condensed polyaromatic radical wherein aromatic radicals are mutually connected with a bond or a crosslinking function).The polyimide can be prepared by reacting 2,6-bis(3-aminophenoxy)pyridine with tetracarboxylic dianhydride in an organic solvent and imidizing resultant polyamic acid.Various tetracarboxylic dianhydrides can be used and particularly prefered are pyromellitic dianhydride and 3,3',4,4'-benzophenonetetracarboxylic dianhydride.

Abstract: A polyetherimide ester polymer comprised of the reaction products of:(i) a diol component comprising at least one low molecular weight diol and at least one high molecular weight diol;(ii) at least one dicarboxylic acid or an ester forming reactive derivative thereof; and(iii) a set of reactants selected from(a) (1) at least one high molecular weight poly(oxy alkylene)diamine, and (2) at least one tricarboxylic acid or its derivative, or(b) at least one high molecular weight polyoxyalkylene diimide diacid.The polymer of this invention exhibits improved flexibility; and the diol component (i) contains an amount of high molecular weight diol at least effective to improve the flexibility of the polymer.

Abstract: Homopolycondensates and copolycondensates of the group comprising linear, saturated polyamides, polyesters, polyamide-imides, polyester-imides and polyester-amides based on benzophenonedicarboxylic acids and benzophenonetricarboxylic acids are radiation-sensitive and are particularly suitable for the production of protective coatings and relief images.

Abstract: An aromatic polythioetherimide having a recurring unit of the following general formula (II): ##STR1## wherein --Ar--, which may be the same or different in the polymer, each represents a divalent aromatic residue and ##STR2## which may be the same or different in the polymer, each represents ##STR3## The aromatic polythioetherimides can be melt-molded, are excellent in the balance of mechanical properties and heat resistance, and can be widely used for parts in the electric and electronic fields, housings, automobile parts, aircraft interior parts, sliding parts, gears, cams, insulating materials, heat-resistant films, heat-resistant varnishes, heat-resistant fibers, etc., and preferably can be used as an engineering plastic for gears, cams, etc., and a heat-resistant insulating film material for electronic hardwares.

Abstract: Novel liquid crystalline extended chain polymer compositions comprising a high concentration of one or more extended chain homopolymer(s), copolymer(s), or block polymer(s) and certain strong acids are prepared by admixing a high concentration of one or more selected homo- or hetero-bifunctional monomer(s) with or without oxidation protecting atoms or groups and one or more of a substantially non-oxidizing strong acid(s) having a high or low P.sub.2 O.sub.5 content. Such compositions are capable of exhibiting excellent cohesive strength, and are especially suited to the production of high molecular weight ordered polymer fibers by dry-jet wet spinning. These liquid crystalline compositions are capable of being drawn through long air gap distances and spun at exceptionally high spin draw ratios. Fibers, films and other articles formed from these liquid crystalline compositions exhibit exceptionally high physical and heat resistant properties.

Abstract: Melt-moldable crystalline polyester-imides comprising units of the following formula (IA) ##STR1## wherein R represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or a halogen atom, and n is an integer of 2 to 12, as main recurring units. The polyester-imides are prepared by (1) condensing a starting mixture containing 1 mole of an imidodicarboxylic acid and 2 to 12 moles of an aromatic monohydroxy compound under heat while distilling water out of the reaction system or (1)' condensing a starting mixture comprising 1 mole of trimellitic anhydride, 0.5 to 0.

Abstract: A polyimide powder which can provide a molding having excellent both strength and heat resistance by heat-press molding, and a method for producing such polyimide powder are disclosed. The polyimide powder comprises spherical polyimide particles having a particle size distribution of from 0.5 to 20 .mu.m and a mean particle diameter of from 1 to 15 .mu.m, and comprising a repeating unit represented by the formula ##STR1## wherein Ar represents an aromatic diamine residue.

Abstract: Novel polymers and molding compositions are prepared from acyl halide derivatives of tricarboxylic acids and diamines and about 1 to about 10 percent by weight of phthalic anhydride, trimellitic anhydride or aniline moieties. The polymers are useful in engineering plastics.

Abstract: A process for preparing a polyamide which comprises polycondensing a dicarboxylic acid and a diamine by using a combination of at least one phosphine and at least one disulfide as the condensing agent.

Abstract: Polyester polymers consisting essentially of repeating units having the formula ##STR1## repeating units having the formula--O--Ar.sup.1 --CO-- [II],repeating units having the formula--O--Ar.sup.2 --O-- [III],and repeating units having the formula ##STR2## wherein Ar.sup.1 is selected from ##STR3## Ar.sup.2 is selected from ##STR4## halogen substituted radicals of these radicals, and ##STR5## wherein X is selected from --O--, --S--, --SO.sub.2 --, --CO--, --O(CH.sub.2).sub.n O--.--CH.sub.2).sub.n, and ##STR6## wherein each n independently represents a member having a value of from 1 to 10, and each R.sup.4 is independently selected from alkyl radicals of 1 to 5 carbon atoms, andR.sup.2 and R.sup.3 are independently selected from hydrogen atom, halogen radicals, alkyl radicals of 1 to 5 carbon atoms, and phenyl radical, and R.sup.2 and R.sup.3 may be identical or different from each other, andR.sup.

Abstract: An organic silicon-terminated polyimide precursor having a very stable solution viscosity is produced by polycondensing 100 parts by weight of a mixture composed of 90 to 99.5% by mole of an organic diamine represented by the following general formula (I) and 10 to 0.5% by weight by mole of an organic silyl represented by the following general formula (II): ##STR1## wherein R.sup.1 and R.sup.2 are divalent organic groups; R.sup.3 and R.sup.4 are monovalent organic groups; m is 0, 1, 2, or 3, with an organic tetracarboxylic acid dianhydride represented by the following general formula (III) in a molar amount corresponding to the 100 parts by weight of the mixture of the organic diamine and the organic silyl represented by the said general formulae (I) and (II), respectively, in an organic polar solvent at 0.degree. to 40.degree. C., thereby obtaining a solution of organic silicon-terminated polyimide precursor, and heating the solution at 50.degree. to 80.degree. C.: ##STR2## wherein R.sup.

Abstract: High temperature fluorinated polyimides having repeating polymer units of the formula ##STR1## wherein X is aromatic or aliphatic. The polyimides can be made by oxidizing 1-phenyl-1,1-bis (3,4-xylyl)-2,2,2-trifluorethane to form 4,4'(2,2,2-trifluoro-1-phenylethylidene)biphthalic tetra carboxylic acid and dehydrating that to form 4,4'(2,2,2-trifluoro-1-phenyl-ethylidene-biphthalic tetra carboxylic acid dianhydride. The dianhydride is polymerized with a diamine to form a polyamic acid which is further imidized to the polyimide. Alternatively, the dianhydride can be esterified to form a 4,4'(2,2,2-trifluoro-1-phenylethylidene)-biphthalic tetracarboxylic acid dialkylester which is then polymerized with a diamine to form a polyamic acid which can then be imidized to a polyimide.

Abstract: Aromatic polyimide compositions, useful in particular for manufacturing adhesive materials, varnishes and films withstanding high temperatures, having a high solubility in organic solvents, particularly polar solvents and which are manufactured by reacting, in such a solvent, a tetraester or diacid-diester of benzhydrol 3,3', 4, 4' tetracarboxylic acid with an aromatic diamine for a sufficient time to obtain a polycondensation reaction product having an inherent viscosity at 30.degree. C., at a concentration of 5 g/liter in N-methyl pyrrolidone, ranging from 0.1 to 2 dl/g.

Abstract: A semiconductor device containing an .alpha.-rays shielding resin layer on at least active portion of a semiconductor element, said .alpha.-rays shielding resin being a special polyimide resin, is excellent in thermal resistance at the time of sealing the semiconductor element, adhesion of the .alpha.-rays shielding layer to the semiconductor element, and .alpha.-rays shielding ability.

Abstract: Carboxy-terminated prepolymers are prepared by the reaction of a diamine, preferably an aromatic diamine, or a mixture thereof with a triamine, with a carboxy anhydride such as trimellitic anhydride and a dianhydride such as bisphenol A dianhydride. The prepolymers, or functional derivatives thereof, are then reacted with a diisocyanate or diamine, or a mixture thereof with a triisocyanate or triamine, preferably an aromatic diisocyanate, to produce copolyamideimides. The products prepared using triamines or triisocyanates are crosslinked. Other products containing alkyl or alicyclic groups attached to aromatic radicals can be oxidatively crosslinked, e.g., by heating in air.

Abstract: Melt-fusible copolyimides based on pyromellitic anhydride and two defined classes of aromatic diamines, at least one diamine of each class being incorporated into the polyimide, each diamine class being present in an amount of 10-90 mole percent of the total diamine content (100 mole percent), melt below about 400.degree. C. and can be fabricated into articles, or can be applied to either fibrous or nonfibrous substrates to make prepregs, tapes, etc., which then are shaped into final articles, such as printed circuit boards or aircraft panels.

Abstract: An aromatic polythioetheramide-imide having a recurring unit of the following general formula (II): ##STR1## wherein --Ar--, which may be the same or different in the polymer, each represents a divalent aromatic residue. The aromatic polythioetheramide-imides are excellent in the balance of mechanical properties, heat resistance and moldability and can be used widely for parts in electric and electronic fields, housings, automobile parts, aircraft interior parts, sliding parts, gears, insulating materials, heat-resistant films, heat-resistant varnishes, heat-resistant fibers, etc.

Abstract: Novel polymers and molding compositions are prepared from acyl halide derivatives of tricarboxylic acids and diamines and about 1 to about 10 percent by weight of phthalic anhydride, or trimellitic anhydride or aniline moieties. The polymers are useful in engineering plastics.

Abstract: This invention provides novel polymers which are characterized by a recurring structural unit that contains a pendant quinoid structure and that exhibits nonlinear optical response.The following structure is illustrative of an invention polymer: ##STR1## where m is an integer of at least 3.

Abstract: Crystalline polyimides having low glass transition temperatures and high solvent resistance are obtained by reacting diamino-oligo-phenylene sulfides with aromatic tetracarboxylic acids or their anhydride derivatives. The diamino-oligo-phenylene sulfides can be of varying length and can be reacted with the dianhydride by conventional processes.

Abstract: A novel series of polymers and copolymers based on a polyimide backbone with the incorporation of carbonate moieties along the backbone. The process for preparing these polymers and copolymers is also disclosed as is a novel series of dinitrodiphenyl carbonates and diaminodiphenyl carbonates. The novel polymers and copolymers exhibit high temperature capability and because of the carbonate unit, many exhibit a high degree of order and/or crystallinity.

Abstract: A composition and a process for the preparation of modified polyimide foams possessing outstanding resistance to high humidity environments which comprises the step of preparing a foamable composition by mixing a solution of an ester of benzophenonetetracarboxylic acid dianhydride and caprolactam with a polyamine to form a resin precursor which when heated foams contemporaneously with the polymerization of the reactants. Two solvents with different boiling points are used to produce a two phase system which yields spray dried powders completely free of the lower boiling point solvent.

Abstract: A polyester, a polyester/polyamide or a polyester/polyamide/polyimide polymers are prepared from (a) a diaryl terephthalate or diaryl isophthalate, and (b) an aromatic polyol or of (a) and a mixture of (b), and an aromatic diamine, or of (a), (b), (c), and (d) a triaryl mellitate, or a copolycarbonate of any of the foregoing including units derived from (e) a diaryl carbonate. The resulting polyester, polyamide, polyester/polyamide or polyester/polyamide/polyimide polymers are adapted for use an an insulating coating on an electrical conductor.

Abstract: Polyimides are prepared from acetylene substituted polyimide oligomers via an addition polymerization reaction which involves homopolymerization. These polymers exhibit low void content when cured and possess superior thermal stability characteristics and physical properties such as structural strength. One of their unique properties is their ability to be processed into useful articles at moderate pressures and temperatures.