Abstract: Compositions comprising: (a) from about 51% to about 99.9% by weight of a polyamide resin component; and (b) from about 0. 1% to about 49% by weight of a wax component, wherein the polyamide resin component comprises a reaction product obtained by reaction of a dimerized fatty acid reactant, a carboxylic acid reactant and a diamine reactant, are disclosed for use in thermographic printing. The polyamide resin/wax component compositions disclosed herein exhibit decreased bloom and enhanced scratch/scuff resistance.

Abstract: A process of increasing the melt processing of synthetic polyamides, in particular pigmented and/or filled synthetic polyamide, by adding thereto an additive having the formula (I) wherein R1 represents a methyl group as such or in the form of a stabilizer masterbatch composition. The invention also relates to modified synthetic polyamides obtainable by this process having improved properties due to the stabilization effect of the compound of the above formula (I).

Abstract: The polyamic acid of the invention can be obtained by the reaction of an acid anhydride component comprising pyromellitic anhydride and 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane with 2,2′-di-substituted-4,4′-diaminobiphenyls as a first aromatic diamine and any aromatic diamine component, as a second aromatic diamine, of 2,2-bis(4-aminophenoxyphenyl)propanes, 1,1-bis(4-(4-aminophenoxy)-3-t-butyl-6-methylphenyl)butane, 2,2-bis(3-amino-4-methylphenyl)hexafluoropropane and &agr;,&agr;′-bis(4-aminophenyl)diisopropylbenzenes in an organic solvent. The polyimide resin of the invention can be obtained by heating such a polyamic acid solution. In the production of a circuit board, by using a photosensitive polyamic acid having a sensitizer incorporated in such a polyamic acid solution, a patterned polyimide resin layer can be provided as an insulation layer on a metal foil.

Abstract: A method for controlling the properties of the product polymer of a polymerization process to improve the process productivity and product quality in both batch and continuous production of polyamides.

Abstract: Disclosed in the present invention is a process for modifying a polyamide polymer comprising contacting a reactive modifier with diamine/diacid salt and/or an amino-acid of a hydrolyzed lactam or lactam to form a modified polyamide. A second embodiment of the present invention is a process for modifying a polyamide polymer comprising contacting a reactive modifier with diamine then contacting the resulting modified diamine with diacid and/or lactam to form a modified polyamide.

Abstract: The invention concerns a process and device for producing high-viscosity or highly stabilized, reaction-stable polyamides, in particular polyamide 6, with reactive amino end groups of less than 50 &mgr;eq/g and for continuously demonomerizing polyamides. The object of the invention is to produce simply, reliably and economically a high-viscosity or highly stabilized reaction-stable polyamide, in particular polyamide 6, and if necessary to carry out continuous demonomerization. According to the invention, the molten polyamide is brought into intimate contact, or intimately mixed with preheated nitrogen in a reaction system in at least one stage and a specific dwell time is set for the melt in a liquid phase. During the production of polyamide 6, expelled lactam is processed and fed to a polymerization reactor.

Abstract: The invention relates to the use of polyamide moulding compounds, their alloys or blends, which contain at least one homopolyamide, which has been obtained from long-chained aliphatic monomer blocks with cycloaliphatic monomer blocks, in order to manufacture moulded members for optical or electro-optical applications.

Abstract: For producing a polyamide having an unreacted caprolactam content of from 0 to 0.5% by weight and an oligomer content of from 0 to 1.25% by weight and having a relative viscosity in a 0.01 g/ml solution of sulfuric acid at 25° C. of from 2.2 to 8.0, combined is a first step of polymerizing a starting material comprising caprolactam, under atmospheric pressure to prepare a polymerization product having an unreacted caprolactam content of not larger than 25% by weight and an oligomer content falling between 0 and 1.8% by weight, and a second step of heating the polymerization product prepared in the first step, at a temperature T satisfying the following formula (1) and under reduced pressure to thereby remove the unreacted caprolactam and the oligomer from it: Glass transition point of polyamide<T<melting point of polyamide+150° C.

Abstract: A process for producing a polyamide from dicarboxylic acid monomer and diamine monomer comprises the steps of: (a) mixing molten dicarboxylic acid monomer and molten diamine monomer in equimolar amounts, thereby producing a molten reaction mixture; (b) flowing the reaction mixture through at least one unvented reaction vessel, the residence time of the reaction mixture in the at least one unvented reaction vessel being between about 0.01 minutes and about 30 minutes, thereby forming a first product stream that comprises polyamide and water of polymerization; and (c) flowing the first product stream through at least one vented vessel, whereby water of polymerization is removed, thereby forming a second product stream that comprises polyamide. The process can operate continuously, and there is no need to add water to the dicarboxylic acid, to the diamine, or to the reaction mixture.

Abstract: A method for producing polyamides, and to a method for producing primary polycondensates which are intermediates for polyamide production. More precisely, the invention relates to a method for producing primary polycondensates, which comprises a step of polycondensing a dicarboxylic acid component having a terephthalic acid content of from 60 to 100 mol % and a diamine component in which the amount of 1,9-nonanediamine and/or 2-methyl-1,8-octanediamine falls between 60 and 100 mol %, in the presence of water of being from 15 to 35% by weight, at a reaction temperature falling between 250.degree. C. and 280.degree. C. and under a reaction pressure (P) that satisfies the following formula (1):P.sub.0 .gtoreq.P.gtoreq.0.7 P.sub.0 (1)where P.sub.

Abstract: This invention relates to high temperature, semi-crystalline, semi-aromatic nylon copolymers with improved shrinkage and blistering resistance, made from terephthalic acid (TA), hexamethylene diamine (HMD) and another aliphatic dicarboxylic acid as monomers. These polymers display superior % TD (Transverse Direction) annealing shrinkage, superior resistance to blistering when formulated with flame retardant additives and reinforcement under infrared (IR) reflow soldering conditions for electronic conectors, as well as a very good balance of mechanical performance as high temperature nylons.

Abstract: A method for binding ceramic materials in aqueous media is disclosed. The method utilizes water-soluble cross-linked polyamides prepared by condensation polymerization for binding various classes of ceramic materials.

Abstract: A process for making a high molecular weight poly(phosphoester) comprising the recurring monomeric units: ##STR1## wherein X is --O-- or --NR"--, where R" is H or alkyl; L is a divalent organic moiety, with the proviso that L cannot have the formula ##STR2## R' is H, alkyl, alkoxy, aryl, aryloxy, heterocyclic, or heterocycloxy; and n is from about 25 to 2000,is described. The process comprises the steps of:(a) substantially dissolving p moles of a di-XH compound in a solvent comprising more than 75% toluene at a first temperature between about -75.degree. C. and 60.degree. C. to form a reaction mixture;(b) while maintaining the reaction mixture at the first temperature, adding q moles, where p.apprxeq.q, of a phosphorodihalo compound;(c) gradually increasing said first temperature at a rate of less than about 2.degree. C. per minute as necessary to achieve a second temperature between about 0.degree. C. and 110.degree. C.

Abstract: A polyamide composition which is amorphous and transparent, which has reduced flammability, and which has reduced migration of flame-retardant additive so that it is film-free, includes at least one polyamide which contains cycloaliphatic monomer units and which is amorphous and transparent; and a flame-retardant additive which is present in an amount effective to reduced flammability of the polyamide composition, which is dissolved in the at least one polyamide, and which is at least one alkyl phosphonic acid compound having a general formula: ##STR1## wherein R and R' each represent, independent of each other, an alkyl group having from 1 to 4 carbon atoms, and x=0 or 1. An article molded from this composition is transparent, has reduced flammability, and has reduced migration of flame-retardant additive so that it is film-free.

Abstract: This invention relates to high temperature, semi-crystalline, semi-aromatic nylon terpolymers with improved shrinkage resistance, made from terephthalic acid (TA), hexamethylene diamine (HMD) and/or 2-methyl pentamethylene diamine (2-MPMD) and another aliphatic dicarboxylic acid as monomers. These polymers display superior % TD (Transverse Direction) annealing shrinkage, as well as very good balance of mechanical performance as high temperature nylons.

Abstract: Improved high temperature polyamides, and particularly partially-aromatic polyamides, containing less than about 40 .mu.eq/g carboxylic acid endgroups. When stabilized with a copper-containing thermal stabilizer, the polyamides exhibit improved thermal oxidative stability.

Abstract: Polyamides are built up from, as fundamental building blocks (a), lactams or aminocarboxylic acids or mixtures of these,as fundamental building blocks (b), from 1 to 50 .mu.mol of at least tribasic amines or carboxylic acids per gram of polyamide,as fundamental building blocks (c), dibasic carboxylic acids or amines andas fundamental building blocks (d), monobasic carboxylic acids or amines,where (c) and (d) are carboxylic acids if (b) are amines, and (c) and (d) are amines if (b) are carboxylic acids,the equivalents ratio of the functional groups of (b) to the functional groups of (c) and (d) together is from 60:40 to 40:60 andthe equivalents ratio of the functional groups of (c) to the functional groups of (d) is from 15:85 to 60:40.

Abstract: A process is provided for preparing a dispersion of a polyamide in water, said process comprising:forming a solution of a polyamide having an acid value of greater than about 2 in an organic solvent to form a solution of said polyamide in said solvent, said polyamide and said solvent being at a temperature below the softening point of said polyamide during said dissolving, said solution further comprising a surfactant, wherein at least a portion of the acid value of said polyamide is neutralized,adding sufficient water to said solution with mixing to form an oil-in-water dispersion, the temperature of said solution and said water being below the softening point of said polyamide during said adding, andremoving at least a major amount of said organic solvent from said oil-in-water dispersion. The resulting dispersion is useful in preparing a coating of the polyamide, which coating is useful as an adhesive.

Abstract: Curative compositions of amine terminated polyamide resins blended with a deaminated bis-(p-aminocyclohexyl)methane composition (DeAms) are useful for curing adhesive epoxy resin compositions. The polyamides comprise combinations of fatty mono-acids, dimer acids, polyethyleneamines, and piperazine ring containing polyamines which are piperazine or N-aminoalkylpiperazine, where the alkyl chain is a C2 to C6 alkyl chain, wherein the ratio of equivalents of fatty mono-acid to dimer acid can range from about 0.001:1 to about 1:1, the ratio of moles of piperazine ring containing polyamine to polyethylene amine can range from about 0.1:1 to about 1:1, and the ratio of moles of polyamine to equivalents of acid can range from about 0.6:1 to about 1.2:1. DeAms is blended at 2 to 40 wt % based on polyamide. Adhesive compositions comprising these curatives are also disclosed.

Abstract: Disclosed is a method of bonding integrated circuit chips to lead frames where the leads are later soldered. A solution of an adhesive polyimide is used. The polyimide is the reaction product of an aromatic dianhydride and a mixture of an aromatic diamine and an aliphatic diamine.

Abstract: A method for binding ceramic materials in aqueous media is disclosed. The method utilizes water-soluble polyamides prepared by condensation polymerization for binding various classes of ceramic materials.

Abstract: An uncoated lens, especially for use as the lens of a fog light or a headlight for an automobile, and having particularly good resistance against the environmental effects which are inherent in this environment, is formed of a colorless, transparent copolyamide having a glass transition temperature of at least a 170.degree. C., blended with a homopolyamide, and wherein the copolyamide is formed from at least one cycloaliphatic diamine with two cyclohexane rings, and at least one aromatic dicarboxylic acid which is predominantly isophthalic acid. The copolyamide may optionally contain up to 20 mol % of a further polyamide forming monomer of at least one lactam or an omega-aminocarboxylic acid. The homopolyamide is preferably one of PA6, PA11, PA12, PA66, PA69, PA610 or PA612. The cycloaliphatic diamine of the copolyamide is preferably bis(3-methyl-4-aminocyclohexyl)-methane.

Abstract: A method for binding ceramic materials in aqueous media is disclose. The method utilizes water-soluble polyamides prepared by condensation polymerization for binding various classes of ceramic materials.

Abstract: A copolyamide composition prepared from hexamethylene diamine and either mixtures of adipic acid and terephthalic acid, or mixtures of adipic acid, terephthalic acid and isophthalic acid, has a melting point below 320.degree. C., a glass transition temperature between 100.degree. C. and 120.degree. C. and physical properties similar to nylon 66.

Abstract: A process is provided for preparing a dispersion of a polyamide in water, said process comprising:dissolving a polyamide having an amine value of greater than about 2 in an organic solvent to form a solution of said polyamide in said solvent, said polyamide and said solvent being at a temperature below the softening point of said polyamide during said dissolving, said solution further comprising a surfactant and an inorganic alkaline material,adding sufficient water containing an acid to said solution with mixing to form an oil-in-water dispersion, the temperature of said solution and said water being below the softening point of said polyamide during said adding, the amount of said acid being sufficient to neutralize a portion of said inorganic alkaline material, but insufficient to coagulate said polyamide from the resulting oil-in-water dispersion, andremoving at least a major amount of said organic solvent from said oil-in-water dispersion.

Abstract: A water solvent extraction degreasing method capable of reducing degreasing time without consideration of abrupt decomposition/vaporization and swelling caused by heat. An organic binder is removed from a molded product that is produced by a powder material mixed with the organic binder and this organic binder contains at least one water-soluble organic compound and at least one water-insoluble thermoplastic resin. The degreasing step of this method includes a water solvent extraction step for extracting the water-soluble organic compound from the organic binder contained in the molded product, using water as a solvent.

Abstract: This invention relates to a nonwoven web and fibers comprising a water soluble polyamide and articles constructed therefrom. The water soluble polyamide may be used alone or in combination with conventional thermoplastic web and fiber forming materials such as water insoluble polyethylene, polypropylene, polyester and polyamide. The water soluble polyamide may also be combined with biodegradable or selectively dispersible material to form nonwoven webs and fibers having various combinations of properties. Such water soluble webs and fibers have utility in the manufacture of disposable absorbent articles such as disposable diapers, feminine napkins, incontinent products and cellulosic articles such as tissues and towels, as well as for water soluble heat fusible webs for the textile industry.

Abstract: This invention relates to a nonwoven web comprising a water soluble polyamide and articles constructed therefrom. The water soluble polyamide may be used alone or in combination with conventional thermoplastic web forming materials such as water insoluble polyethylene, polypropylene, polyester and polyamide. The water soluble polyamide may also be combined with biodegradable or selectively dispersible material to form nonwoven webs having various combinations of properties. Such water soluble webs have utility in the manufacture of disposable absorbent articles such as disposable diapers, feminine napkins, incontinent products and cellulosic articles such as tissues and towels, as well as for water soluble heat fusible webs for the textile industry.

Abstract: A method of making paper in which dry chemical additives are incorporated into the pulp mixture by addition of an entire bag containing the additive directly to the mixture, the improvement being that the bag is sealed with an adhesive closure, the adhesive being a hot melt consisting essentially of a water dispersable polyamide prepared from a diacid component comprising in major portion an aliphatic diacid of 6 or fewer carbon atoms and a diamine component consisting of one or more compounds of the formula :H.sub.2 N--C.sub.y H.sub.2y --(OC.sub.2 H.sub.4).sub.x --O--C.sub.y H.sub.2y --NH.sub.2where y is 2 or 3 and x is 1-50 and a wax. Such bags will not leak in shipping and handling, and yet can be added directly to paper batches at ambient temperature in the manner of the unsealable bags employed in the prior art.

Abstract: The process for single-stage postcondensation of a polycondensate in a fluidized bed reactor (1) includes feeding the polycondensate through the fluidized bed reactor (1); circulating a main stream of nitrogen carrier gas through the fluidized bed reactor; withdrawing a fractional stream at a temperature of from 20.degree. to 230.degree. C. from the main stream of the nitrogen carrier gas; passing the fractional stream through a water-filled gas scrubber column (15) so as to form a conditioned stream of the nitrogen carrier gas with a predetermined dew point between 10.degree. to 80.degree. C.; and returning the conditioned stream to the main stream. In preferred embodiments the polycondensate is allowed to cool during a cool-down stage at an end of the postcondensation and the withdrawal of the fractional stream from the main stream is halted, but the circulating of the main stream through the fluidized bed reactor is continued during the cool-down stage.

Abstract: An aromatic polyamide resin composition composed of two types of aromatic polyamide (A) and (B), where (A) is an aromatic polyamide wherein the molar ratio of aromatic polyamide with respect to the monomer components that constitute the polyamide is 0.4 or greater, and (B) is an aromatic polyamide containing an aromatic monomer as the monomer component that constitutes the polyamide and has a recrystallization temperature that is lower than that of the aromatic polyamide (A), where said aromatic polyamide resin composition has a recrystallization temperature that is 10.degree. C. or more lower than the recrystallization temperature of the aromatic polyamide (A).Merit:The aromatic polyamide composition of the present invention has the high heat resistance characteristic of aromatic polyamides, superior dimensional stability with respect to water absorption, and maintenance of physical stability and chemical resistance, while providing improved molding characteristics.

Abstract: A low-cost thermal decomposition degreasing method capable of drastically reducing the time required for a degreasing process which involves heating, vaporization and thermal decomposition, while assuring the shape retention property of an injection molded product during degreasing. The degreasing process comprises: (i) a first step wherein a molded product placed under a reduced pressure less than or equal to atmospheric pressure is heated at a temperature lower than the melting point of a thermoplastic binder so that the thermoplastic binder partially evaporates by 5 wt % or more, and then the molded product is further heated at a temperature lower than higher one of the melting points of a more volatile organic compound and a thermoplastic resin whereby the thermoplastic binder further evaporates by 10 wt % or more, and wherein the final temperature is set to 200.degree. C.

Abstract: The invention relates to a mixture in powder form and comprising (i) at least one polyamide and (ii) at least one polymer (A) containing hydroxyl functional groups and compatible with the polyamide. The polymer (A) may be an ethylene/vinyl alcohol copolymer. The mixture may be used to coat metal substrates.

Abstract: A polyamide resin comprising the reaction product obtained by the reaction of an acid component comprised of a major concentration of a dimer acid and minor concentration of a monobasic acid and an amine component comprised of a major concentration of a short-chain alkylenediamine, a first minor concentration of a medium-chain alkylenediamine and second minor concentration of a polyoxyalkylene diamine having a molecular weight greater than about 500 is provided. The polyamide resin is used to form a blend of containing the polyamide in a major amount by weight and a first minor amount by weight of a polar wax and a second minor amount by weight of a polyolefin elastomer. The composition is used to reinforce a footwear upper, e.g. as a print on box toe material.

Abstract: Thermoplastic molding materials containA) from 1 to 99% by weight of a partly aromatic copolyamide composed ofa.sub.1) from 30 to 44 mol % of units which are derived from terephthalic acid,a.sub.2) from 6 to 25 mol % of units which are derived from isophthalic acid,a.sub.3) from 43 to 49.5 mol % of units which are derived from hexamethylenediamine anda.sub.4) from 0.5 to 7 mol % of units which are derived from aliphatic cyclic diamines of 6 to 30 carbon atoms,the molar percentages of components a.sub.1) to a.sub.4) together giving 100%,B) from 1 to 99% by weight of a polyetherimide,C) from 0 to 30% by weight of a polymeric component having OH groups,D) from 0 to 60% by weight of fibrous or particulate fillers or mixtures thereof,E) from 0 to 40% by weight of rubber impact modifiers andF) from 0 to 40% by weight of conventional additives and processing assistants.

Abstract: A process is provided for preparing a dispersion of a polyamide in water, said process comprising:dissolving a polyamide having an amine value of greater than about 2 in an organic solvent to form a solution of said polyamide in said solvent, said polyamide and said solvent being at a temperature below the softening point of, said polyamide during said dissolving, said solution further comprising a surfactant and an inorganic alkaline material,adding sufficient water containing an acid to said solution with mixing to form an oil-in-water dispersion, the temperature of said solution and said water being below the softening point of said polyamide during said adding, the amount of said acid being sufficient to neutralize a portion of said inorganic alkaline material, but insufficient to coagulate said polyamide from the resulting oil-in-water dispersion, andremoving at least a major amount of said organic solvent from said oil-in-water dispersion.

Abstract: Improved high temperature polyamides, and particularly partially aromatic polyamides, containing less than about 40 .mu.eq/g carboxylic acid endgroups, when stabilized with a copper-containing thermal stabilizer, the polyamides exhibit improved thermal oxidative stability.

Abstract: A copolyamide composition prepared from hexamethylene diamine and mixtures of adipic acid, terephthalic acid and isophthalic acid, has a melting point below 300.degree. C., a glass transition temperature between 100.degree. C. and 130.degree. C. and physical properties similar to nylon 66.

Abstract: A process for the activated anionic lactam polymerization is proposed, wherein a liquid system is employed, which simultaneously contains activator and anionic catalyst for the polymerization of the lactam.

Abstract: A polyamide resin composition having good molding fluidity, heat and chemical resistance and dimensional stability is provided containing: (A) 30-90 weight percent, based on components (A) and (B), of a polyamide resin containing (i) 10-99 weight percent, based on components (i) and (ii) of an aromatic polyamide containing a carboxylic acid component derived from terephthalic acid or a mixture of terephthalic and isophthalic acid in which the isophthalic acid constitutes 40 mole percent or less of the mixture, and an aliphatic diamine component derived from a mixture of hexamethylene diamine and 2-methylpentamethylene diamine; and (ii) 1-90 weight percent, based on components (i) and (ii), of at least one polyamide selected from the group consisting of polyamides containing repeat units derived from alipathic dicarboxylic acids and alipathic diamines and polyamides containing repeat units derived from aliphatic aminocarboxylic acids; and (B) 10-70 weight percent, based on components (A) and (B), of an inorgan

Abstract: This invention concerns a low temperature process for the manufacture of nylon.

Abstract: A partially aromatic copolyamide is formed of:(a) 5 to 30 weight-% of hexamethylene diamine(b) 10 to 40 weight-% of metaxylylene diamine(c) 15 to 50 weight-% of adipic acid(d) 5 to 45 weight-% of at least one aliphatic dicarboxylic add with 7 to 10 carbon atoms, preferably sebacic acid and/or acelaic acid, wherein the components (a) to (d) add up to 100 weight-%, and the add groups and the amine groups are essentially present in equimolar portions. These novel copolyamides are used for producing barrier layers for mono- or multi-layered composites, such as foils or containers, infusion- or ostomy bags, shrink wraps for meat, fish and cheese packagings or sausage skins, wherein the copolyamides can be present in the pure form or as a mixture with other polymers, in particular in combination with further polymer layers.

Abstract: A random copolymerized polyamide resin is prepared by reacting a lactam of the formula (I): ##STR1## wherein R.sup.1 is a C.sub.2-11 alkylene group optionally substituted with a substituent having 1 to 6 carbon atoms, with a hexamethylenediamine-adipic acid salt while concentrating the aqueous solution of the salt to a concentration of at least 70% by weight and while maintaining a uniform reaction phase at all times by controlling the pressure over and the temperature of the reaction medium such that the hexamethylenediamine-adipic acid salt does not precipitate, said pressure being up to not greater than 2 kg/cm.sup.2 .multidot.G and said temperature being up to not greater than 150.degree. C., and then mixing in the solution of the lactam of formula (I) thereby effecting copolymerization and forming a polyamide resin having a relative viscosity measured by the sulfuric acid solution method (1% at 25.degree. C.) of 1.5 to 8.0.

Abstract: A composition of matter useful as a hotmelt adhesive is provided. The adhesive comprises a polyamide based on dimerized fatty acid, preferably having an amine value of less than 2, and at least one heat stabilizer for polyvinyl chloride, preferably selected from the group consisting of alkyl tin carboxylate compounds and epoxy compounds. The heat stabilizer is preferably present in an amount of 0.2% to 10.0% by weight of the composition. Also provided is a method of using the composition as a hotmelt adhesive for polyvinyl chloride.

Abstract: Partly aromatic semicrystalline thermoplastic polyamide molding compositions containA) from 40 to 100% by weight of a copolyamide composed ofa.sub.1) from 30 to 44 mol % of units which are derived from terephthalic acid,a.sub.2) from 6 to 20 mol % of units which are derived from isophthalic acid,a.sub.3) from 43 to 49.5 mol % of units which are derived from hexamethylenediamine anda.sub.4) from 0.5 to 7 mol % of units which are derived from aliphatic cyclic diamines of 6 to 30 carbon atoms,the molar percentages of components a.sub.1) to a.sub.4) together giving 100%, andB) from 0 to 50% by weight of a fibrous or particulate filler,C) from 0 to 30% by weight of an elastomeric polymer andD) from 0 to 30% by weight of conventional additives and processing assistants,the percentages by weight of components A) to D) together giving 100%.

Abstract: Directly shapeable clear solutions of polyamide imides and a method for preparing same are provided. The solutions are obtained by polycondensation in .gamma.-butyrolactone (.gamma.BL) in substantially stoichiometric proportions between toluylene diisocyanate and an aromatic acid anhydride, and by dilution in (.gamma.BL) to give a solution allowing them to be processed at a later stage. Yarns and fibers made from said solutions are also described.

Abstract: Colorless, transparent copolyamides, made up of monomers based on cycloaliphatic diamines and aromatic dicarboxylic acids and a maximum of 20 mol % of further polyamide-forming aliphatic monomers, which have glass transition temperatures of at least 175.degree. C., their blends and alloys, along with the molded articles that can be produced from them and a process for their preparation are proposed.

Abstract: The invention provides a continuous process for the preparation of polyamides, equipment in which the polymerization process can be conducted, and process control methods for said polymerization process.

Abstract: A process for the continuous production of polyamides from a mixture of at least one lactam and water and, if required, other monomer units and/or conventional additives and fillers under polyamide-forming conditions, where the mixture of the starting materials is heated in liquid phase in a first reaction zone until a conversion of at least 70% is reached, and undergoes adiabatic decompression and further polymerization in another reaction zone, wherein, in the first reaction zone, 0.5-7% by weight of water are employed, the temperature is increased to the range from 220.degree. to 310.degree. C., and polymerization is carried out until a conversion of at least 85% is reached and, in the second reaction zone, after the decompression further polymerization is carried out in the range from 215.degree. to 300.degree. C. without heat input.

Abstract: A polyamide (9-T polyamide) comprising (a) 60 to 100 mole of terephthalic acid and (b) a diamine component comprising 60 to 100 mole % of 1,9-nonanediamine, said polyamide having an intrinsic viscosity ?.eta.! as determined by measurement in concentrated sulfuric acid at 30.degree. C. of 0.6 to 2.0 dl/g and having at least 10% of terminal groups thereof blocked. Another polyamide (9M-T polyamide) comprises a dicarboxylic acid component (a) comprising 60 to 100 mole % of terephthalic acid and a diamine component (b) comprising 60 to 100 mole % of 1,9-nonanediamine and 2-methyl-1,8octanediamine, the molar ratio between said 1,9 nonanediamine and said 2-methyl-1,8-octanediamine being in a range of 60:40 to 99:1, said polyamide having an intrinsic viscosity ?.eta.! as determined by measurement in concentrated sulfuric acid at 30.degree. C. of 0.4 to 3.0 dl/g.