Abstract: A process for producing a polyamide through direct polycondensation of a diamine component, which contains at least 70 mol % of a xylylenediamine containing at least 20 mol % of paraxylylenediamine, and a dicarboxylic acid component, substantially in the absence of a solvent and using a batch reactor equipped with a partial condenser; the process comprising the following steps: (1) a step of feeding the dicarboxylic acid component into the reactor, and then pressurizing the reactor to increase the inner pressure to a pressure of at least 0.1 MPaG, (2) a step of continuously or intermittently adding the diamine component to the dicarboxylic acid component while the pressure inside the reactor is kept at 0.1 MPaG or more and while the reaction system is kept in a uniform flow state as a whole, (3) after the addition of the diamine component, a step of lowering the pressure inside the reactor to atmospheric pressure or less at a pressure-lowering speed of from 0.1 to 1.0 MPa/hr.

Abstract: The present invention relates to novel imide oligomer compositions, polyimides formed therefrom, and methods for making and using the same. In particular, the invention relates to novel polyimide oligomers comprising 3,3?,4,4?-benzophenone tetracarboxylic dianhydride (BTDA), 2-(3,4-dicarboxy phenyl)-1-phenylacetylene anhydride (PE), and a mixture of 1,3-diaminobenzene and 4,4?-(1,3-phenylenediisopropylidene) bisaniline. The polyimide oligomers demonstrate low melt viscosity (these resins are melt processable) while retaining exceptional thermo-oxidative stability, high glass transition temperature, and good mechanical properties in the cured state.

Abstract: Polyamide having a melting point between 330° C. and 370° C., said polyamide comprising: a diamine component (a) comprising between 0 and 55 mole %, based on the total number of moles of the diamine component (a), of at least one aliphatic diamine having more than 6 carbon atoms, and between 45 and 100 mole %, based on the total number of moles of the diamine component (a), of at least one aliphatic diamine having at most 6 carbon atoms, and a dicarboxylic acid component (b) comprising more than 50 mole %, based on the total number of moles of the dicarboxylic acid component (b), of terephthalic acid, with the exception of a certain specific polyamide (P*).

Abstract: The present invention is directed to the use polycyclic diamines. These diamines, when polymerized with dianhydrides, and optionally other non-polycyclic diamines are used to form new polyamic acids. The polyamic acids can be imidized to form a new class of useful polyimide resins and polyimide films, particularly in electronics type applications.

Abstract: A semi-aromatic polyamide resin is provided which has a high level of residence stability, hot-water resistance and chemical resistance and is also excellent in adhesive properties and compatibility with other resins and the like. The semi-aromatic polyamide resin comprises: dicarboxylic acid units in which 50 to 100 mol % of the dicarboxylic acid units are aromatic dicarboxylic acid units; and diamine units in which 60 to 100 mol % of the diamine units are aliphatic diamine units having 9 to 13 carbon atoms. Furthermore, at least 10% of terminal groups of molecular chains of the polyamide resin are blocked with a terminal-blocking agent, and the amount of terminal amino groups of the molecular chains is 60 ?eq/g or more and 120 ?eq/g or less. In addition, [NH2]/[COOH]?6 is satisfied, where [NH2] (?eq/g) represents the amount of the terminal amino groups and [COOH] (?eq/g) represents the amount of terminal carboxyl groups.

Abstract: This disclosure covers polymers, some of which are useful in medical device applications. The polymers comprise at least two different blocks, at least one L1 block with the formula and at least one L2 block with the formula Medical devices comprising these polymers, mixtures of these polymers with therapeutic agents, and methods of making these polymers and mixtures are within the scope of this disclosure. Some of these medical devices are implantable within a mammalian body, such as in a body lumen.

Abstract: Dispersants for pigments as well as dispersions of pigments containing them, and compositions such as inks and coatings containing them are described. The dispersants are the reaction product of a dialkylsuccinyl succinate and an amine.

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

Abstract: An improved aqueous cathodic electrocoating composition that contains an anti-crater agent which is a water-reducible polyester resin having an acid value less than 40 mg KOH/g. The water-reducible polyester is the reaction product of (1) a hydroxy cyclic carbonate; (2) a polycarboxylic acid anhydride; (3) optional monofunctional epoxy resin; (4) a polyfunctional epoxy resin; and, (5) a polyamine compound containing tertiary amine and either primary or secondary functionality. The reaction product is neutralized in the presence of acid and water to convert the tertiary amine groups to water-dilutable groups. Hydrolyzable silane groups can also be incorporated into the reaction product to further enhance its crater resistance property. The electrocoat composition produces coatings having a smoother appearance with fewer craters without adversely affecting intercoat adhesion of the cured film to subsequent coating layers applied thereover.

Abstract: An improved aqueous cathodic electrocoating composition that contains an anti-crater agent which is a water-reducible polyester resin having an acid value less than 40 mg KOH/g. The water-reducible polyester is the reaction product of (1) a hydroxy cyclic carbonate; (2) a polycarboxylic acid anhydride; (3) optional monofunctional epoxy resin; (4) a polyfunctional isocyanate resin; and, (5) a polyamine compound containing tertiary amine and either primary or secondary functionality. The reaction product is neutralized in the presence of acid and water to convert the tertiary amine groups to water-dilutable groups. Hydrolyzable silane groups can also be incorporated into the reaction product to further enhance its crater resistance property. The electrocoat composition produces coatings having a smoother appearance with fewer craters without adversely affecting intercoat adhesion of the cured film to subsequent coating layers applied thereover.

Abstract: In the present invention, a masterbatch is produced by melt-mixing a metal compound (B) with a reactive thermoplastic resin (C). The oxidizable polyamide (A) is produced by polycondensing a diamine component containing m-xylylenediamine in an amount of 70 mol % or higher with a dicarboxylic acid component containing adipic acid in an amount of 50 mol % or higher. The metal compound (B) contains at least one metal selected from the group consisting of transition metals in group VIII of the periodic table, manganese, copper and zinc. The reactive thermoplastic resin (C) has an internal bond and/or a reactive functional group which are reactive with an amide bond and/or a reactive functional group of the oxidizable polyamide (A). The masterbatch exhibits a stable moldability. The masterbatch is melt-mixed with an oxidizable polyamide (A) and formed into a molded article which exhibits an excellent oxygen-absorbing ability irrespective of the preservation conditions of the masterbatch.

Abstract: In the production method of polyamide of the present invention, the mole balance at a set point during melt polymerization is estimated from a pre-established equation for calculating the mole balance during melt polymerization from a melt viscosity. On the basis of the estimated mole balance, the subsequent conditions of melt polymerization of a batch and the polymerization conditions of the next and subsequent batches are determined. In addition, the mole balance, molecular weight and relative viscosity of melt-polymerized polyamide are estimated from pre-established equations each for respectively calculating the mole balance, molecular weight and relative viscosity at the end point of melt polymerization from the melt viscosity. The conditions for solid phase-polymerizing the melt-polymerized polyamide are determined on the basis of estimated values.

Abstract: An object of the present invention is to provide a fluorinated polymer of adequate molecular weight with excellent transparency in a wavelength range from visible to near infrared, and to also provide a method of producing such a polymer. The present invention provides a fluorinated polymer comprising a structure represented by a formula (1) as a structural unit, as well as a method of producing this polymer using a corresponding tetrafluoroxylylenediamine or a tetrafluoroxylylene glycol as a raw material.

Abstract: New photosensitive PBO precursor polymers which contain diazoquinone moieties attached to its backbone and in which all amino end groups are converted into amide groups. The photosensitive formulation based on the disclosed PBO precursor polymers have good imaging and mechanical properties as well as superior shelf life stability. Photosensitive polybenzoxazole precursor polymers having (sulfon)amide end groups (with or without attached diazoquinone groups) can be formulated into photosensitive compositions with diazoquinone photoactive compounds which lack benzylic hydrogens on the backbone to yield compositions producing films significantly lighter in color after curing.

Abstract: A process for the production of high molecular weight polybenzimidazole by one: providing a first reaction vessel; charging the reaction vessel with at least one aromatic hydrocarbon tetraamine, and a heterocylic ring making up the dicarboxylic component; heating the reactants under agitation in a substantially oxygen-free atmosphere with agitation until the agitator torque is about 1.5 times the torque before a rise in viscosity begins; terminating the agitation while continuing to heat the reaction mixture to about 230° C. while allowing the reaction mass to foam; cooling the reaction mass to a friable foamed mass; crushing the friable foamed mass to obtain a ground prepolymer; and two: providing a second reaction vessel, the second reaction vessel being a high intensity reaction vessel; transferring the ground prepolymer to the second reaction vessel; heating the ground prepolymer under agitation to over 315° C. at atmospheric pressure for a time of about 90 minutes.

Abstract: Packaging materials made from water-soluble nylons are disclosed, that readily contain materials such as caustic chemicals and upon exposure to water dissolve to provide for the release of the chemical into an aqueous environment. The materials are made from select polyether diamines and select aliphatic dicarboxylic acids.

Abstract: In the production method of the present invention, the polyamide is produced by the polycondensation of a diamine component and a dicarboxylic acid component comprising a straight-chain ?,?-aliphatic dicarboxylic acid and an aromatic dicarboxylic acid. The dicarboxylic acid component is first made into a suspension phase of the solid aromatic dicarboxylic acid in a molten straight-chain ?,?-aliphatic dicarboxylic acid. A part of the diamine component is added while the reaction system is in the suspension phase. Then, the reaction system is made into a homogeneous molten phase, to which the rest of the diamine component is added. Finally, the reaction system is kept at temperatures within a specific range to complete the polycondensation.

Abstract: The invention relates to new thermoplastically processible transparent polyamide molding materials based on copolyamides containing diamines and dicarboxylic acids with aromatic cores which exhibit a high index of refraction nD20 over 1.59 and a low density under 1.3 g/cm3. At the same time, a low birefringence, high hardness, and scratchresistance are achieved. The polyamide molding materials are fabricated by means of conventional pressure reactors (autoclaves) according to a modified technique. The granulate that is produced from the inventive molding materials is reshaped by thermoplastic processes like injection molding, particularly in multichamber cavity tools. The invention also relates to the utilization of the inventive molding materials for producing optical lenses.

Abstract: The fuel-barrier polyamide resin of the present invention is a product of the polycondensation of a diamine component comprising 70 mol % or higher of m-xylylenediamine and a dicarboxylic acid component comprising 70 mol % or higher of a mixed dicarboxylic acid which comprises a C4 to C20 ?,?-linear aliphatic dicarboxylic acid and at least one dicarboxylic acid selected from the group consisting of isophthalic acid and naphthalenedicarboxylic acid in a molar ratio of 30:70 to 95:5. The polyamide resin is excellent in not only fuel-barrier property and heat resistance, but also moldability and recyclability, and therefore suitably used as a barrier material of fuel containers.

Abstract: Homo- and/or copolymers of one or more ethylenically unsaturated monomers, suitable for the preparation of molded articles that feature improved properties, especially improved fracture properties, heat stability and notched impact strength are disclosed. These homo- and/or copolymers are characterized in that they contain less than 400 particles per m2 of surface area with a diameter greater than 200 ?m.

Abstract: A process for a single-stage melt polymerization for the production of a high molecular weight polybenzimidazole which comprises the steps of: providing a reaction vessel having a means for agitation and a means for vacuum; charging the reaction vessel with reactants selected from: (A) a tetraaminiobiphenyl (TAB), and (B) a diphenyl isophthalate (DPIP); reacting the reactants under constant agitation and under a vacuum with an inert gas sweep; maintaining a reactant temperature which does not exceed 290° C. under constant agitation allowing pressure in the vessel to increase, with an inert gas sweep until a phase change is achieved, when the temperature reaches 250° C. pressure is increased to a slight positive pressure; and increase the reactant temperature and pressure within said reaction vessel while maintaining constant agitation and inert gas sweep, while maintaining a slight positive pressure. Preferably the vessel used in the instant invention is a high intensity reaction vessel.

Abstract: In a two-step precondensate process for preparing polyamides diamines are reacted with dicarboxylic acid dihalides in a polar, non-basic, inert organic liquid medium under conditions such that a condensation product having a low degree of polymerization is formed. The resulting condensation then is contacted with an aqueous solution of a water-soluble acid acceptor by continuously feeding the components into a reactor system having a total residence time from about 2 seconds to about 2 minutes, and having a Peclet number greater than about 3.5 to form a polyamide product having a high degree of polymerization.

Abstract: Provided is a polyamide composition comprising 100 parts by weight of (A) a polyamide having dicarboxylic acid units containing 60 to 100 mol % of terephthalic acid units, and diamine units containing 60 to 100 mol % of 1,9-nonanediamine units and/or 2-methyl-1,8-octanediamine units, and 5 to 100 parts by weight of (B) a titanium oxide with an average particle size of 0.1 to 0.5 ?m. The polyamide composition shows excellent heat resistance enough to withstand the SMT process, and gives a molded article with excellent whiteness and surface-reflectance.

Abstract: The invention relates to a continuous process for manufacturing polyamides. The polyamides are of the type obtained from diacids and diamines. The process comprises an operation of continuous mixing of a compound which is rich in amine end groups and a compound which is rich in acid end groups and a polycondensation operation using the mixture. The invention relates to the starting phase of such a process, during which an aqueous solution comprising a mixture of monomers in substantially stoichiometric proportions is used.

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: Transparent polyamide molding materials are provided which are characterized in that they have a melting enthalpy between 0 and 12 J/g and the polyamides are constituted of 100 mole-% of a diamine mixture having 10-70 mole-% of PACM [bis-(4-amino-cyclohexyl)-methane] with less than 50 wt.

Abstract: The present invention relates to novel aspartates, their method of production and the use of these aspartates as reactive components for polyisocyanates in two-component polyurethane coating compositions and for preparing polyurethane prepolymers. The aspartates are prepared by first reacting a di- or polyamine with an unsaturated ester and then reacting the resultant product with a maleimide.

Abstract: The present invention contemplates a process for forming polyaminoamide polymers formed by the reaction of a dibasic acid/ester with excess amounts of an amine; the intermediate polymer resulting therefrom; a process for synthesizing effective, high solids resins resulting from the reaction of intermediate polymers with an epihalohydrin; and the resultant high, solids resin. These resins may be used as wet strength resins in the papermaking industry.

Abstract: The invention concerns copolyamides obtained by using multifunctional monomers. It consists in using a multifunctional monomer comprising at least three reactive functions and at least another multifunctional monomer, in amounts such that the terminal group concentrations are balanced. The copolyamides are particularly high viscosity copolyamides. The invention also concerns compositions based on said copolyamides.

Abstract: The invention concerns copolyamides obtained by using multifunctional monomers. It consists in using at least one multifunctional monomer comprising at least three reactive functions and at least another multifunctional monomer, in amounts such that the terminal group concentrations are balanced. The copolyamides are more particularly high viscosity copolyamides. The invention also concerns compositions based on said copolyamides.

Abstract: An acid-dyeable polyester composition comprising (a) polyester and (b) secondary amine or secondary amine salt in an amount effective to promote acid-dyeability. The acid-dyeable polyester composition may be prepared by melt blending: the polyester; and polymeric additive prepared from (i) triamine containing secondary amine or secondary amine salt unit(s) and (ii) one or more other monomer and/or polymer units. One polymeric additive comprises polyamide selected from the group consisting of poly-imino-bisalkylene-terephthalamide, -isophthalamide and -1,6-naphthalamide, and salts thereof. Also, the polymeric additive, the blends, shaped articles (e.g., fibers and films), processes of dyeing, and processes for preparing an acid dyeable polyester composition.

Abstract: A polyamide composition comprising 100 parts by weight of (A) a semiaromatic polyamide having dicarboxylic acid units mainly composed of aromatic dicarboxylic acid units and diamine units mainly composed of aliphatic diamine units having 4 to 14 carbon atoms and containing not more than 15 ?eq/g of terminal amino groups; and 0.01 to 5 parts by weight of (B) a copper compound.

Abstract: A method for preparing a nylon 6 copolymer containing dimeric acid comonomers. The method includes reacting 80.0˜99.9 mol % of caprolactam, 0.1˜3.0 mol % of dimeric acid and 0.1˜3.0 mol % of 2-methyl-1,5-pentadiamine in a polymerization reaction. Moreover, the invention provides a method for preparing a nylon 66 copolymer containing dimeric acid comonomers, which comprising reacting 60.0˜90 mol % of hexadiacid and hexadiamine, 0.1˜3.0 mol % of dimeric acid and 0.1-3.0 mol % of 2-methyl-1,5-pentadiamine in a polymerization reaction. The reaction temperature for both of the methods are at 200˜280° C.

Abstract: A method for preparing nylon 6 copolymer containing 5-sulfoisophthalate salts comonomer. The method includes the steps of reacting 5-sulfoisophthalate salts ester with aliphatic diamine in a molar ratio of 2˜20 at 160˜200° C., followed by completely removing the unreacted aliphatic diamine, to obtain the intermediate compound with terminal amine, 5-sulfobenzenediamide compound (formula III). Next, caprolactam and aliphatic diacid (formula IV) are reacted at 200˜260° C. to form an oligomer with a low molecular weight. 5-Sulfobenzenediamide (formula III) and catalyst are then added into the oligomer obtained in previous step to cause a polymerization reaction at 200˜280° C. to obtain nylon 6 copolymer containing 5-sulfoisophthalate salt comonomer. The molar ratio of E/C is 0.005˜0.150 and the molar ratio of D/E is 1.05-1.00. Compounds present in the water extract are greatly reduced.

Abstract: A process for the preparation of novel polyamides, the use of such polyamides for the production of fibers, sheets and moldings, and fibers, sheets and moldings obtainable from such polyamides, are provided.

Abstract: There is provided a process for the continuous polymerization of polyamides which is carried out under conditions of pressure, temperature and polymer concentration in water that will ultimately yield multiple phases (including a second liquid polymer phase or a polymer precipitate). However, a single phase operation is achieved under these conditions by appropriate management of residence time and using a well-mixed reaction environment in early stages of the polymerization.

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: The invention relates to a semi-aromatic polyamide containing at least tetramethylene terephthalamide units and also hexamethylene terephthalamide units. The copolyamide has a melting point higher than approximately 290° C., a high crystallinity and a good stability. Preferably the copolyamide according to the invention contains approximately 30-75 mol % hexamethylene terephthalamide units and also approximately 0.01-20 mol % other units. The invention also relates to a process for the preparation of a semi-aromatic copolyamide containing at least tetramethylene terephthalamide units and hexamethylene terephthalamide units, characterized in that, successively, a first polymerization is effected in the melt phase, followed by an post-polymerization of the low molar mass polymer thus obtained in the solid phase; and to compositions and products that contain said copolyamide.

Abstract: The invention concerns a method for making polyamide. More particularly, the invention concerns a method for making polyamides derived from the reaction between a diacid and a diamine. It concerns a method for making a polyamide derived from the reaction of at least a diacid with at least a polyamide comprising the following steps: preparing a first mixture of diacid and diamine with a diacid/diamine molar ratio ranging between 0.8 and 0.995, preferably ranging between 0.95 and 0.99 in a first reactor (5); preparing a second mixture of diacid and diamine with a diacid/diamine molar ratio ranging between 1.005 and 1.2, preferably between 1.01 and 1.05, in a second reactor (4); introducing in melted form a first flow of the first mixture and a second flow of the second mixture in a stirred polymer reactor (7); drawing, preferably, continuously, from said reactor a flow of polyamide prepolymer; feeding said polyamide flow into a finishing step to obtain the desired degree of polymerisation.

Abstract: The invention describes polyamides having both strongly hydrophilic groups and unsaturated groups, the polyamides consequently being water-dispersible and curable. The hydrophilic groups are distributed along the chain, whereas the unsaturated groups are located at the ends. The polyamides of the invention are useful in many applications, especially in the preparation of intimate blends of polyamides with vinyl, acrylic and/or styrene polymers.

Abstract: Hot melt adhesives are prepared using thermoplastic polyamides derived from polymerized fatty acid components. The adhesives are particularly useful for bonding nonpolar substrates such as poly-&agr;-olefins.

Abstract: In the production of polyamide by the melt-polymerization of the present invention, the polymerization conditions are rapidly and accurately controlled by a near-infrared spectroscopy to enable the efficient production of a desired polyamide with a good stability in its quality.

Abstract: A new paradigm of disease centers around the metabolic pathways of S-adenosyl-L-methionine (SAM), the intermediates of these pathways and other metabolic pathways influenced by the SAM pathways. Methods are provided to analyze and modulate SAM pathways associated with a disease or condition. Such methods permit identification and utilization of diagnostic and therapeutic protocols and agents for such disease states and conditions.

Abstract: Copolyamides, consisting of polycondensation products of the following components: caprolactam 10 to 45 mol-%, laurolactam 30 to 55 mol-%, at least 2 dicarboxylic acids 20 to 50 mol-% of the following compounds, aliphatic &agr;,&ohgr;-dicarboxylic acids with 6 up to 14 C atoms inclusively, terephthalic acid, isophthalic acid and 2,6-naphthalene dicarboxylic acid, wherein the content of aromatic dicarboxylic acids is lower than 10 mol-%, with reference to the allover amount of the above-mentioned components, which add up to 100 mol-%, a diamine mixture in an amount that is equimolar to that of the dicarboxylic acids, chosen from the group of the following substances, hexamethylene diamine, piperazine and/or 2-methyl-1,5-diaminopentane, wherein the molar content of hexa-methylene diamine is between 75 and 95 mol-% with reference to the diamine mixture. The copolyamides according to the invention are used for the production of mono- and multifilaments, fibers, films and nets.

Abstract: This invention relates to the synthesis of dithiocarboxylic acid esters by reaction of bis(thioacyl) disulphides, thioacetals or vinylidane bis(thioether) with free-radicals (optionally in the presence of monomers). The invention also relates to processes for the synthesis of polymers utilising these dithioesters as polymerisation regulators (chain transfer agents) or to the use of bis(thioacyl) disulphides to generate dithioester chain transfer agents in situ.

Abstract: The improved polyamide production method of the present invention is characterized by including a step of accurately regulating the molar balance between a diamine component and a dicarboxylic acid component to a desired balance in a batch-wise regulation tank, thereby preparing a slurry liquid substantially free from the amidation reaction. The slurry liquid thus prepared is fed to a batch-wise or continuous polymerization reactor, where the amidation reaction is proceeded to easily produce polyamide having a desired balance of the diamine component and the dicarboxylic acid component without causing a problem such as foaming, solidification, etc.

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.

Abstract: An essentially non-osteoconductive medical device is described comprising a biodegradable terephthalate copolymer comprising the recurring monomeric units shown in formula I: wherein R is a divalent organic moiety; x is ≧1; and n is 3-7,500, where the biodegradable polymer is sufficiently pure to be biocompatible and is capable of forming biocompatible residues upon biodegradation. Compositions containing the copolymers and biologically active substances, articles useful for implantation or injection into the body fabricated from the compositions, and methods for controllably releasing biologically active substances using the copolymers, are also described.

Abstract: In the process of the present invention, a recovered polyamide is used as a part of the raw materials for producing polyamide. By carrying out the polycondensation under a condition such that the recovered polyamide is dissolved in the reaction system during the polycondensation, the properties of the polyamide being produced are not deteriorated as compared with those of polyamide which is produced without using the recovered polyamide. By changing the addition amount of the recovered polyamide, the crystallization speed of the resultant polyamide is controlled or increased as compared when produced without using the recovered polyamide.

Abstract: The invention relates to a granule and granulate and to a process for the preparation of polyamide granules at least comprising