Abstract: Solvent resistant, transparent films prepared from solutions of aromatic polyamides and multi-functional carboxylic acids in polar aprotic solvents are described herein. Solvent resistance is achieved by heating the films for a short time above 300° C. near the polyamide Tg. The films have CTEs less than 40 ppm/° C. and are optically clear displaying transmittance above 75% between 400 and 750 nm. The films are useful as substrates for flexible electronic devices.

Abstract: The present invention relates to a polymer according to Formulas (1) or (2): The present invention further relates to nanogels and nanoparticles made of a polymer according to general Formulas (1) and (2). The nanogels may comprise a biologically active component such as siRNA, miRNA, DNA, an (oligo)peptide or a proteins.

Abstract: The invention relates to a copolyamide comprising at least two different units corresponding to the following general formulation: A/X.T A is chosen from a unit obtained from an amino acid, a unit obtained from a lactam and a unit corresponding to the formula (Ca diamine).(Cb diacid), with a representing the number of carbon atoms of the diamine and b representing the number of carbon atoms of the diacid, a and b each being between 4 and 36, advantageously between 9 and 18, X.

Abstract: The invention relates to a copolyamide comprising at least two different units corresponding to the following general formulation: A/X.T A is chosen from a unit obtained from an amino acid, a unit obtained from a lactam and a unit corresponding to the formula (Ca diamine)·(Cb diacid), with a representing the number of carbon atoms of the diamine and b representing the number of carbon atoms of the diacid, a and b each being between 4 and 36, advantageously between 9 and 18, X.

Abstract: A thermosetting oligomer or thermosetting polymer is provided. The thermosetting oligomer or thermosetting polymer contains repeating units, each of which has at least one thermosetting functional group in the side chain and is represented by Formula 1: where repeating units include X1, A1, and Y1 subunits, sidechain units include linking unit L and thermosetting functional group Z, and n is an integer from 1 to 4. The thermosetting oligomer or thermosetting polymer has a low coefficient of thermal expansion and high or no glass transition temperature, stiffness, processability, heat resistance and mechanical properties. The thermosetting oligomer or thermosetting polymer is highly soluble, wettable and dimensionally stable and is suitable for use in films, prepregs and printed circuit boards. Further provided are a thermosetting resin composition including the thermosetting oligomer or thermosetting polymer and a printed circuit board using the composition.

Abstract: The present invention provides an electrophotographic member capable of more definitely suppressing occurrence of a C set image. The electrophotographic member has a surface layer including a modified polysiloxane having a structure represented by the following formula (1). In the formula (1), G represents a bivalent group having an ethylene oxide chain represented by (—O—C2H4—) and L represents polysiloxane having at least a SiO4/2(Q) unit or a SiO3/2(T) unit.

Abstract: Copolymers containing at least one perfluoropolyether segment and multiple aminooxalylamino groups are described. Methods of making the copolymers are also described. The copolymers can be prepared by reacting an oxalylamino-containing compound and an amine compound having at least two primary amino groups, at least two secondary amino groups, or at least one primary amino group plus at least one secondary amino group.

Abstract: The invention relates to a copolyamide comprising at least two different units corresponding to the following general formulation: A/X.T A is chosen from a unit obtained from an amino acid, a unit obtained from a lactam and a unit corresponding to the formula (Ca diamine).(Cb diacid), with a representing the number of carbon atoms of the diamine and b representing the number of carbon atoms of the diacid, a and b each being between 4 and 36, advantageously between 9 and 18, X.

Abstract: The present invention discloses a method of producing a modified polyimide comprising a polycarbonate, which modified polyimide has excellent electric properties and adhesion as well as excellent heat resistance, flexibility, bending property, low warping, chemical resistance and storage stability; and the modified polyimide. Also disclosed are a composition comprising the modified polyimide and used thereof.

Abstract: There is provided a production method of a crystalline polyamide resin by thermal polycondensation of a mixture including at least a diamine component, a dicarboxylic acid component and water as a starting material, wherein the diamine component includes (A) pentamethylene diamine at a ratio that is equal to or greater than 10 mol % and less than 80 mol % relative to a gross amount of the diamine component; and the dicarboxylic acid component includes (B) at least one selected from the group consisting of an aromatic dicarboxylic acid, an alicyclic dicarboxylic acid and dialkyl ester derivatives thereof at a ratio that is equal to or greater than 76 mol % and equal to or less than 100 mol % relative to a gross amount of the dicarboxylic acid component, the production method comprising: a first step that heats the above mixture, which has a water content equal to or less than 30% by weight, at a temperature equal to or higher than 200° C. under a pressure of 1.8 to 3.

Abstract: A process for making a polyamide polymer, said process comprising heating, in one or more ionic liquid(s), one or more polyamide precursor(s) selected from: (i) one or more free dicarboxylic acid(s) or ester(s) thereof, with one or more diamine(s); or (ii) one or more salt(s) of a dicarboxylic acid with a diamine; or (iii) one or more lactam(s); or (iv) mixtures of any of the foregoing precursors (i) to (iii).

Abstract: Polyamides, e.g., polyhexamethylene adipamide, are continuously produced via the following stages: Stage 1: into and through a reactor, polycondensing a liquid stream which contain the polyamide monomer(s) at a pressure P1 greater than atmospheric pressure, the stream of material at the outlet of the reactor including a vapor phase which contains steam and a liquid phase which at least contains the product of polycondensation; Stage 2: feeding the outlet stream of material into a chamber, evacuating at least a portion of the vapor phase therefrom and recovering at least the liquid phase which at least contains the product of polycondensation, the pressure P2 in the chamber being regulated at a set value such that it is greater than atmospheric pressure and the residence time of said liquid phase in the chamber being less than 5 minutes; and Stage 3: pressure reducing at least the liquid phase which at least contains the stream of polycondensation product recovered during Stage 2.

Abstract: The invention relates to a copolyamide comprising at least two different units corresponding to the following general formulation: A/X.T A is chosen from a unit obtained from an amino acid, a unit obtained from a lactam and a unit corresponding to the formula (Ca diamine).(Cb diacid), with a representing the number of carbon atoms of the diamine and b representing the number of carbon atoms of the diacid, a and b each being between 4 and 36, advantageously between 9 and 18, X.

Abstract: This invention relates to poly(ester amide)s (PEAs) comprising inactivated terminal amino and carboxyl groups, methods of synthesizing the inactivated PEAs and uses for them in the treatment of vascular diseases.

Abstract: A resin composition, preferably an adhesive composition, comprising a polyether polyamide elastomer capable of being strongly bended with a polyimide resin, preferably strongly bended through an easy process to form an interface between the polyimide resin and the composition, and a bonded composite having the resin composition and a polyimide resin which together form an interface to be bonded with each other. A resin composition for forming an interface together with a polyimide resin for bonding, wherein the resin composition comprises a polyether polyamide elastomer (component R) obtained by subjecting a specific aminocarboxylic acid compound A1 and/or lactam compound A2, polyether compound B, and dicarboxylic acid compound C to polymerization, wherein the content of the component R in the resin composition is 80 to 100% by weight.

Abstract: The present invention generally relates to a poly(bisoxalamide) and a process for preparing and article comprising the poly(bisoxalamide).

Abstract: A method for preparing a water-soluble polyamide, includes copolymerizing reactive monomers including caprolactam; ethylene glycol bis(2-aminoethyl)ether or ethylene glycol bis(3-aminopropyl)ether; and 5-sulfoisophthalic acid monosodium salt, wherein a molar ratio of caprolactam:ethylene glycol bis(2-aminoethyl)ether or ethylene glycol bis(3 -aminopropyl)ether:5-sulfoisophthalic acid monosodium salt is about 0:1:1 to about 5:1:1, advantageously about 1.85:1:1. Copolymerizing takes place at a copolymerization temperature of about 222-250° C. and a copolymerization pressure of about 3 Bar. The method further includes maintaining a temperature of about 222-250° C. for about 2-3 hours under normal pressure after the copolymerization step. The water-soluble polyamide has a solubility in water of about 10-70%.

Abstract: The invention relates to the use of a molding composition which comprises at least 50% by weight of a copolyamide, which is composed of the following monomer combination: a) from 65 to 99 mol % of a substantially equimolar mixture composed of an unbranched aliphatic diamine having from 6 to 18 carbon atoms and of an unbranched aliphatic dicarboxylic acid having from 6 to 18 carbon atoms, ?where the mixture composed of diamine and dicarboxylic acid comprises an average of from 8 to 12 carbon atoms, b) from 1 to 35 mol % of a substantially equimolar mixture composed of a cycloaliphatic diamine having from 8 to 20 carbon atoms and of a dicarboxylic acid having from 6 to 18 carbon atoms, for production of a printable or printed item, such as a ski topcoat.

Abstract: The invention pertains to an aramid copolymer composition comprising an aramid copolymer having at least one arylene carboxylic acid moiety and at least one hydroxyarylene moiety, or comprising an aramid copolymer having at least one arylene carboxylic acid moiety or having at least one hydroxyarylene moiety, and a crosslinker agent. The invention further relates to crosslinked copolymers derived thereof and shaped articles comprising said crosslinked copolymers.

Abstract: A molding compound, containing at least 30% by weight of a copolyamide, which is derived from the following monomers: a) 50 to 95 mole percent of the combination of a diamine, selected from the group consisting of 1,9-nonane diamine, 1,10-decane diamine, 1,11-undecane diamine and 1,12-dodecane diamine, and terephthalic acid, and b) 5 to 50 mole percent of the combination of a diamine, selected from the group consisting of 2,2,4-trimethylhexamethylene diamine, 2,4,4-trimethylhexamethylene diamine, and mixtures thereof, and terephthalic acid. The copolyamide is crystalline and has low water absorption.

Abstract: A linear polyimide is produced from mellophanic dianhydride, diamine (NH2-A-NH2), and a monofunctional acid anhydride and contains a repeating unit represented by the following general formula (3): wherein A represents a divalent aromatic diamine residue or aliphatic diamine residue, B represents a monofunctional acid anhydride residue, and n represents a degree of polymerization.

Abstract: Provided is a low-cost polyimide, containing cyclohexane diamine as a diamine unit, that has a low thermal expansion coefficient. Said block polyimide contains blocks having the repeating structural unit shown in formula (1A) and blocks having the repeating structural unit shown in formula (1B). This block polyimide is preferably obtained by imidizing a block polyamide acid imide that contains blocks having the repeating structural unit shown in formula (2A) and blocks having the repeating structural unit shown in formula (2B).

Abstract: Disclosed is a photosensitive resin composition capable of displaying satisfactory patterning performance against an alkaline developer and yielding a cured film of a sufficiently low coefficient of linear thermal expansion. The photosensitive resin composition contains a photopolymerization initiator and a polyimide precursor obtained by the reaction of an ester-containing diamine such as 4-aminophenyl 4?-aminobenzoate, a biphenyl-based diamine such as 4,4?-diamino-2,2?-dimethylbiphenyl, and an unsaturated group-containing diamine such as 4,4?-diamino-2,2?-divinylbiphenyl with an acid anhydride such as pyromellitic dianhydride. The content of the structural unit derived from the unsaturated group-containing diamine in the polyimide precursor is 5-60 mol %.

Abstract: The invention relates to a plastic container or conduit for a cooling system, a heating system, an air intake system, an exhaust system, a pressure system or a fuel system, consisting of or comprising a part or a layer made of a thermoplastic polymer composition comprising a semi-crystalline semi-aromatic polyamide having a glass transition temperature (Tg) of at least 115° C.

Abstract: Tailorable polyimide resin systems suitable for processing by resin transfer molding (RTM) and resin infusion (RI) methods. An exemplary resin system includes first and second prepolymer components present in respective amounts to provide the desired processibility. The cured polyimide system exhibits high glass transition temperature and other properties required for gas turbine engine applications. The first and second prepolymer components independently comprise a monomeric mixture or a reaction product of a diamine component, a dianhydride component, and an end group component.

Abstract: The invention relates to a polyamide comprising at least two units having the following general formula: 4.Y in which: 4 denotes butanediamine, and Y represents a dicarboxylic acid chosen from a linear or branched aliphatic dicarboxylic acid, a cycloaliphatic diacid and an aromatic diacid, the dicarboxylic acid containing from 7 to 11 carbon atoms, the butanediamine contains carbon of renewable origin, except for the fact that when the polyamide is a copolyamide, it cannot contain 100% by mass of organic carbon derived from renewable raw materials relative to the total mass of polyamide carbon. The invention also relates to a composition comprising this polyamide and the use of this polyamide and of such a composition.

Abstract: The present invention relates to a copolyamide comprising at least two units and corresponding to the following general formula: A/(diamine).(Cw diacid), in which: the diamine is a cycloaliphatic diamine, w represents the number of carbon atoms of the diacid, A is chosen from a unit obtained from an amino acid or from a lactam and a unit corresponding to the formula (Cx diamine).(Cy diacid), with x representing the number of carbon atoms of the diamine and y representing the number of carbon atoms of the diacid, and in which at least one of the monomers chosen from A and the Cw diacid is obtained, in all or part, from renewable starting materials according to Standard ASTM D6866. The invention also relates to a composition comprising this copolyamide and to the use of this copolyamide and of such a composition.

Abstract: The invention relates to a polyamide comprising at least two units having the following general formula: X.Y where: X is an alkylaromatic diamine and Y is an aliphatic carboxylic diacid selected from dodecanedioic (C12) acid, tetradecanedioic (C14) acid, hexadecanedioic (C16) acid, characterized in that the carboxylic diacid comprises organic carbon from a renewable source determined according to standard ASTM D6866 The invention also relates to a composition comprising this polyamide and the use of said polyamide and of such a composition.

Abstract: Disclosed is a polyamide resin which is produced by the polycondensation of (A) pentamethylenediamin, (B) terephthalic acid and/or a derivative thereof, and (C) at least one member selected from adipic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, isophthalic acid, 1,9-diaminononane, 1,10-diaminodecane, 1,12-diaminododecane, caprolactam, undecalactam, laurolactam, aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, and derivatives of these compounds. In the polyamide resin, the ratio of a repeating unit derived from the component (C) is 10 to 50 wt % (inclusive) relative to the total weight of the polymer. A solution of the polyamide resin in 98% sulfuric acid, which contains the polyamide resin at a concentration of 0.01 g/ml, has a relative viscosity of 1.5 to 4.5 at 25° C.

Abstract: An object of the present invention is to provide a copolymerized polyether polyamide resin for coating on or for impregnation to a woven or knitted fabric, which resin further enhances slippage resistance and tear strength affecting the developing property of an airbag which is one of the automobile safety parts, as compared with those in the prior art. According to the present invention, a copolymerized polyether polyamide resin for coating on or for impregnation to a woven or knitted fabric is provided, characterized in that, elongation and elastic modulus of the copolymerized polyether polyamide resin are not less than 1000% and not more than 15 MPa, respectively.

Abstract: The invention relates to a composition, and structures having a layer made of said composition, in which the composition is, by weight, the total being 100%: 50 to 100% of at least one polyamide A1 of formula X.Y/Z or 6.Y2/Z in which: X denotes the residues of an aliphatic diamine having from 6 to 10 carbon atoms, Y denotes the residues of an aliphatic dicarboxylic acid having from 10 to 14 carbon atoms, Y2 denotes the residues of an aliphatic dicarboxylic acid having from 15 to 20 carbon atoms and Z denotes at least one unit chosen from the residues of a lactam, the residues of an ?,?-aminocarboxylic acid, the unit X1, Y1 in which X1 denotes the residues of an aliphatic diamine and Y1 denotes the residues of an aliphatic dicarboxylic acid, the weight ratios Z/(X+Y+Z) and Z/(6+Y2+Z) being between 0 and 15%; 0 to 40% of a plasticizer; 0 to 50% of an impact modifier; and 0 to 50% of a polyamide A2.

Abstract: An absorbent material formed at least in part of a cross-linked polymer. The absorbent material has a centrifuge retention capacity as determined by a Centrifuge Retention Capacity Test of at least about 20 g/g and a gel bed permeability under load as determined by a Gel Bed Permeability Under Load Test of at least about 300×10?9 cm2 or a free swell gel bed permeability as determined by a Free Swell Gel Bed Permeability Test of at least about 2,500×10?9 cm2. The cross-linked polymer may comprise either at least about 75 weight percent anionic polymer or at least about 75 weight percent cationic polymer. In one embodiment, the cross-linked polymer is surface treated with a water soluble non-cross-linked polymer having a potential for becoming charged opposite that of the cross-linked polymer.

Abstract: It is to provide a high purity oxydiphthalic anhydride with which, in production of a polyimide containing an oxydiphthalic anhydride, one having sufficiently high strength can be produced, and an industrially simple process for producing it. A high purity oxydiphthalic anhydride, which has a content of fine insoluble particles having a projected area diameter of from 5 to 20 ?m, of at most 3,000 particles per 1 g, and has a light transmittance at 400 nm of at least 98.5% in a light path length of 1 cm when dissolved in acetonitrile at a concentration of 4 g/L.

Abstract: Provided herein are methods for preparing maleimides, polyimides and maleimide-terminated polyimides. Specifically disclosed are methods for preparing maleimides from N-substituted maleamic acids in the presence of an alcohol catalyst and an acid co-catalyst in a solvent. Also disclosed are methods for preparing polyimides by reacting a diamine with a dianhydride in a reaction medium that includes a solvent and a polar protic co-solvent. Further provided are methods for preparing maleimide-terminated polyimides from diamines in an aromatic solvent containing a polar protic co-solvent.

Abstract: Tailorable polyimide resin systems suitable for processing by resin transfer molding (RTM) and resin infusion (RI) methods. An exemplary resin system includes first and second prepolymer components present in respective amounts to provide the desired processibility. The cured polyimide system exhibits high glass transition temperature and other properties required for gas turbine engine applications. The first and second prepolymer components independently comprise a monomeric mixture or a reaction product of a diamine component, a dianhydride component, and an end group component.

Abstract: The present invention relates to a flexible semiaromatic polyamide composition with a low moisture uptake comprising, by weight, the total being 100: 60 to 99.5% (preferably 70 to 93%) of at least one copolyamide of formula X/Y,Ar in which: Y denotes the residues of an aliphatic diamine having from 8 to 20 carbon atoms, Ar denotes the residues of an aromatic dicarboxylic acid, X denotes either the residues of aminoundecanoic acid NH2—(CH2)10—COOH, of lactam-12 or of the corresponding amino acid, or X denotes the unit Y,x, residue from the condensation of the diamine with an aliphatic diacid (x) having between 8 and 20 carbon atoms, or X denotes the unit Y,I, residue from the condensation of the diamine with isophthalic acid, ?0.5 to 40% (preferably 7 to 30%) of at least one product chosen from plasticizers, nanofillers, polyolefins, crosslinked polyolefins and additives.

Abstract: Provided is a continuous production method of a polyamide with stabilized polymerization degree and good quality, particularly an aromatic-containing polyamide.

Abstract: A composition comprises a condensation product of an amine-reactive fluorinated polyether and a polyamine. The compositions may be in dispersed in water.

Abstract: Polymer derivatives based upon polyalkyleneimine backbones having from about 20% to about 60% of their reactive amino functionalities substituted by C14-20 carboxylic acids, are disclosed. Fiber lubricants and/or sizing compositions comprising such polymer derivatives are also disclosed. The disclosed fiber lubricants exhibit excellent affinity for fiberglass fibers and have excellent hydrophobicity, while also providing excellent lubrication. Methods for preparing said derivatives are also disclosed. Also disclosed are methods for treating fibers using the polymer derivatives.

Abstract: Copolymers having linked internal polyether blocks and internal polyamide blocks have advantageous physical properties and solvent-gelling abilities. The copolymer may be prepared from a reaction mixture that contains 1,4-cyclohexane dicarboxylic acid (CHDA) and poly(alkyleneoxy) diamine (PAODA). Optionally, the reaction mixture contains no monofunctional compound reactive with either amine or carboxylic acid groups, however some of this monofunctional compound may be present. Dimer diamine and/or dimer acid may be present in the reaction mixture. A copolymer may also be prepared from a reaction mixture containing dimer acid and at least two diamine compound(s) including PAODA and short-chain aliphatic diamine having 2-6 carbons (SDA), wherein: a) the reaction mixture comprises x grams of PAODA and y grams of SDA, and x/(x+y) is 0.8-0.98; b) the reaction mixture weighs z grams, and x/z is at least 0.

Abstract: Polyetherpolyamide elastomer showing a low water absorption, a high stress relaxation, and a high elastic recovery percentage of elongation is obtainable by polymerizing an aminocarboxylic acid compound and/or a lactam compound, a triblock polyetherdiamine compound having the following formula, and a dicarboxylic acid compound: [x is a value of 1 to 20, y is a value of 4 to 50, z is a value of 1 to 20].

Abstract: A series of initiators based on transition metal complexes for the polymerization of optically active beta-lactams into poly-beta-peptides and block copolymers have been developed. These initiators are unique in being able to eliminate chain transfer and chain termination side reactions from these polymerizations resulting in narrow molecular weight distributions, molecular weight control, and the ability to prepare copolymers of defined block sequence and composition.

Abstract: Golf balls comprising thermoplastic, thermoset, castable, or millable elastomer compositions are presently disclosed. These elastomer compositions comprise reaction products of polyisocyanates and telechelic polymers having isocyanate-reactive end-groups such as hydroxyl groups and/or amine groups. These elastomer compositions can be used in any one or more portions of the golf balls, such as inner center, core, inner core layer, intermediate core layer, outer core layer, intermediate layer, cover, inner cover layer, intermediate cover layer, and/or outer cover layer.

Abstract: Golf balls comprising thermoplastic, thermoset, castable, or millable elastomer compositions are presently disclosed. These elastomer compositions comprise reaction products of polyisocyanates and telechelic polymers having isocyanate-reactive end-groups such as hydroxyl groups and/or amine groups. These elastomer compositions can be used in any one or more portions of the golf balls, such as inner center, core, inner core layer, intermediate core layer, outer core layer, intermediate layer, cover, inner cover layer, intermediate cover layer, and/or outer cover layer.

Abstract: The polyamide resin of the present invention is produced by the polycondensation of a dicarboxylic acid component and a diamine component containing xylylenediamine and bisaminomethylcyclohexane in a total amount of 70 mol % or higher. The polyamide resin contains impurities having a boiling point of from 150 to 300° C. at ordinary pressure and a solubility parameter of from 8 to 16 in a total amount of 0.3% by weight or lower based on the weight of the polyamide resin. The polyamide resin is free from various inconveniences due to inclusion of the impurities, and suitably used in applications for molding materials, bottles, sheets, films and fibers.

Abstract: A mixture substantially comprising caprolactam and water is heated for at most 30 minutes to obtain a polyamide prepolymer having an amino end group content of at least 0.1 mmol/g and a cyclic oligomer content of at most 0.6% by weight. An aqueous solution of caprolactam having a water content of from 2 to 20% by weight is heated under pressure at a temperature of from 200 to 330° C. for 1 to 30 minutes to obtain a polyamide prepolymer having an amino group content of at least 0.1 mmol/g and a cyclic oligomer content of at most 0.6% by weight.

Abstract: Copolymers designed for use as particulate carriers containing functionalizable amino acid subunits for coupling with targeting ligands are described. The copolymers are polyesters composed of &agr;-hydroxy acid subunits such as D,L-lactide and pseudo-&agr;-amino acid subunits which may be derived from serine or terpolymers of D,L-lactide and glycolide and pseudo-&agr;-amino acid subunits which may be derived from serine. Stable vaccine preparations useful as delayed release formulations containing antigen or antigens and adjuvants encapsulated within or physically mixed with polymeric mircoparticles are described. The particulate carriers are useful for delivering agents to the immune system of a subject by mucosal or parenteral routes to produce immune responses, including antibody and protective responses.

Abstract: A process for the production of polyamides is disclosed. In a first reaction step, suitable monomers such as caprolactam or an aliphatic aminocarboxylic acid are reacted with polyfunctional amines, which contain at least one secondary amino group, and/or with salts containing such amines and dicarboxylic acids. The reaction product is in a further process step undergoes solid phase post-condensation.

Abstract: A process for producing polyamides from dinitriles and diamines in a continuous reaction using subsequent heating steps. In particular, the process involves contacting a dinitrile, a diamine, water, and optionally a catalyst to form a reaction mixture; heating the reaction mixture to a first elevated temperature of between about 180 to about 240° C., maintaining said temperature for about 0.10 to about 20 hours, and optionally controlling the pressure in this heating step by venting; heating the reaction mixture to a second elevated temperature of between about 250 to about 350° C., adding water to the reaction mixture before or after the second elevated temperature is reached, maintaining the pressure in the second heating step above atmospheric pressure by venting at least some of the water, and maintaining the second elevated temperature for a period of about 0.10 to about 10 hours; and recovering the polyamide.

Abstract: In the process for producing polyamide of the present invention, a diamine and a dicarboxylic acid are melt-polycondensed in a batch-wise fist polymerizer in the absence of a solvent to produce a middle-stage polyamide. The diamine has a boiling point higher than a melting point of the middle-stage polyamide being produced under inner pressures of the first polymerizer. The middle-stage polyamide is fed into a continuous second polymerizer while controlling the change of relative viscosity within ±0.2, and further polycondensed there to produce the objective polyamide. With such a process, the change of polymerization degree of the middle-stage polyamide during the switching of the polymerization step from a batch-wise manner to a continuous manner is avoided, thereby preventing the variation in quality of the final product.