Abstract: The invention provides a polymer composed of vinyl monomers bearing imidazole, hydroxyl and carboxyl groups arranged in proximity to each other, that exhibits hydrolytic activity similar to serine proteases, and a process for its preparation. The polymer is useful for the hydrolysis of esters and amides to the corresponding alcohols and amines.

Abstract: This invention discloses non-crosslinked, poly-branched polymers having a comb-burst configuration and a process for preparing such polymers.

Abstract: Absorbent gelling materials are prepared by crosslinking polyaspartate units. The crosslinked homopolymers exhibit improved gel volumes, gel strengths and extractable material characteristics. Using diamine crosslinkers in an amount of 2.5-30 percent by weight, the blue-dextran saline gel volumes of at least 15 can be obtained. Similarly, gel strengths of 300 N/m.sup.2 or better, including gel strengths above 3000 N/m.sup.2, can be obtained. The resulting product is susceptible of a variety of uses, is biodegradable, and can be prepared in a particle size suitable for use in a diaper.

Abstract: Polyaspartate, useful for inhibition of incrustations due to materials causing hardness in water and of value in detergent formulations, can be prepared by reacting maleic acid or fumaric acid in a molar ratio of 1:1-2.1 at temperatures greater than 190.degree. C., followed by conversion of the polymer formed in this reaction to a salt of polyaspartic acid by basic hydrolysis.

Abstract: Modified polyaspartic acids useful as detergent and cleaner additives, as water treatment agents and as scale inhibitors in the evaporation of sugar juice are obtainable by polycondensation of(a) from 1 to 99.9 mol % of aspartic acid with(b) from 99 to 0.1 mol % of fatty acids, polybasic carboxylic acids, anhydrides of polybasic carboxylic acids, polybasic hydroxycarboxylic acids, monobasic polyhydroxycarboxylic acids, alcohols, amines, alkoxylated alcohols and amines, amino sugars, carbohydrates, sugarcarboxylic acids and/or non-proteinogenic aminocarboxylic acidsor by polymerizing monoethylenically unsaturated monomers in the presence of polyaspartic acids in the manner of a free-radically initiated graft polymerization.

Abstract: Disclosed are cosmetic melanins of different colors produced by procedures involving oxidative polymerization of monomeric precursors of melanin and/or co-monomers that enhance substantivity or adherence of the melanins to the skin and hair. Also disclosed are methods for preparing cosmetic melanins and methods for using these compositions topically to produce a natural-appearing tan and to prevent damage to skin caused by UV exposure.

Abstract: Polymers with recurring succinyl units are prepared by reaction of maleic anhydride, maleic acid or fumaric acid with condensed liquid ammonia and polymerization of the resulting reaction product.

Abstract: This invention relates to a coprecipitated binder composition used for the compression of pharmaceutically and agriculturally active components to provide a non-friable pill or tablet of increased hardness with remarkably improved rate of dissolution and improved stability in aqueous solution. The invention also relates to the process for preparing the binder and to its incorporation in a formulation with the active ingredient.

Abstract: Sulfonic acid group-containing polyaspartic acid derivatives, some of which are novel, having repeating units of the structures I and II ##STR1## in which ##STR2## are suitable for water treatment and as a detergent additive.

Abstract: Described is a method of reducing resin bleed of a cyanate ester-containing die attach adhesive produced by curing a liquid resin system that contains cyanate ester monomer or mixtures that include cyanate ester monomer by adding an additive comprising at least one alkylene aromatic compound and curing the liquid resin system with the alkylene aromatic compound . Also disclosed is a die attach adhesive that comprises a resin system with an alkylene aromatic compound.

Abstract: Copolymers of polyaspartic acid which are suitable for the inhibition of scale deposition were obtained by reacting maleic acid, an additional polycarboxylic acid and ammonia in a stoichiometric excess, at 120.degree.-350.degree. C., preferably 180.degree.-300.degree. C., to provide copolymers of polysuccinimide. In a second embodiment, a polyamine was added to the reaction mix. These intermediate polysuccinimide copolymers could then be converted to the salts of copolymers of polyaspartic acid by hydrolysis with a hydroxide.Such copolymers are useful in preventing deposition of scale from water and find applications in treating water. Other applications include scale prevention additives for detergents. In addition, such copolymers inhibit dental tartar and plaque formation.

Abstract: A star-like or comb-like branched aliphatic polyamino compound for use as a basic catalyst or a curing agent, as an effective thixotropic agent or viscosity adjusting agent for an aqueous medium, as a component for any one of a coating-forming agent, a sealing agent, a molding material and an adhesive resin, or as a substantially solvent-free coating composition, molding material or adhesive resin. The process for the production of the above compound comprises (a) forming an adduct of ammonia or an aliphatic amino compound having an amino group (compound A) with methyl acrylate, adding an alkylenediamine having 2 to 12 carbon atoms to the adduct to carry out an ester-amide exchange reaction (b), thereby obtaining a polyamino compound (B) having a total of 2 to 100 aliphatic primary amino and secondary amino groups per molecule and having a number average molecular weight of 170 to 10,000, and forming an adduct of the polyamino compound (B) with an acrylic acid ester (C) of the formula (1),CH.sub.2 =CHCOO--R.

Abstract: There is described a process for the preparation of basic poIycondensates, which comprises(a) reacting an amine of formula ##STR1## wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are each independently of one another hydrogen or alkyl which is unsubstituted or substituted by amino, hydroxy, cyano or C.sub.1 -C.sub.4 alkoxy, and A is alkylene which may be substituted or interrupted by one or more than one hetero atom, with an ammonium salt in the presence of an anhydrous solvent, and(b) reacting the protonised product obtained according to (a) with a cyanamide at elevated temperature.The polycondensates or salts thereof prepared according to this process are particularly suitable aftertreatment agents for enhancing the wetfastness properties of dyed or printed textile material.

Abstract: The present invention describes a crosslinked aliphatic polyoxaesters containing amines and/or amido groups and blends thereof with other polymers that may be used to produce surgical devices such as sutures, sutures with attached needles, molded devices, and the like. The crosslinked aliphatic polyoxaesters of the present invention is formed from an aliphatic polyoxaester having a first divalent repeating unit of formula I:?O--C(O)--C(R.sub.1)(R.sub.2)--O--(R.sub.3)--O--C(R.sub.1)(R.sub.2)--C(O)-- !Iand a second repeating unit of the formula:?--O--R.sub.12 --!.sub.U, XVIand optionally a third repeating unit with a formula selected from the group consisting of:?--O--R.sub.4 --!.sub.A, II?--O--R.sub.5 --C(O)--!.sub.B, III(?--O--R.sub.5 --C(O)!.sub.P --O--).sub.L G XIand combinations thereof wherein R.sub.12 contains an internal amine or internal amide group wherein the aliphatic polyoxaester has been crosslinked.

Abstract: The invention relates to a dendritic macromolecule with branches prepared from halogen cyanide units composed of a monohalogenated hydrocarbon compound comprising 3-50 carbon atoms and at least one cyanide group, the halogen and the cyanide group being separated from one another by at least 3 carbon atoms. The invention also relates to a process for the preparation of a dendritic macromolecule, comprising a core and at least one branch emanating from the core, characterized in that the process comprises the steps a) through c):a) substantially every functional group of the core molecule is reacted with monomeric halogen cyanide unitsb) substantially every incorporated cyanide group is reduced to an aminec) substantially every amine group is reacted with monomeric halogen cyanide units,steps b) and c) being conducted alternately.

Abstract: A method for forming a polyamic acid having nonlinear optical (NLO) or pre-NLO side chains, which method includes the steps of:(1) providing a bis-(aromatic dicarboxylic acid anhydride) containing at least one NLO or pre-NLO side chain having the structure represented by:D-R-Awherein D, R and A form a delocalized resonance configuration in which R is a pi-conjugated non-centrosymmetric moiety, A is hydrogen or an electron withdrawing moiety and D is an electron donating moiety covalently linked to the bis-(aromatic dicarboxylic acid anhydride); and(2) reacting the bis-(aromatic dicarboxylic acid anhydride) with an aromatic diamine to form a polyamic acid having NLO or pre-NLO side chains. Methods for preparing polyamic acids having NLO or pre-NLO side chains by reacting aromatic diamines having NLO or pre-NLO side chains with bis-(aromatic dicarboxylic acid anhydrides) are also disclosed. Methods of forming the polyamic acids into polyimides having NLO side chains are also included.

Abstract: Polysuccinimide, polyaspartic acid and salts of polyaspartic acid may be prepared by means of heating aspartic acid in the presence of sodium bisulfate. The molecular weight of the polymers may be increased from that obtained without the use of sodium bisulfate. The polysuccinimide, polyaspartic acid or salt of polyaspartic acid obtained have low color. Polyaspartic acid may be obtained in this manner directly from the effluent of an immobilized cell or enzyme column which catalyzes the production of L-aspartic acid without the necessity of intermediate isolation steps.

Abstract: Polymers of maleic acid may be prepared by thermally polymerizing malic acid, maleic acid or fumaric acid with less than one equivalent of ammonia. The polymers are modified by the incorporation of amines, carboxylic acids or combinations thereof. The polymers formed are excellent inhibitors of alkaline earth salt deposition, dispersants, tartar control additives, detergent additives, and water treatment agents.

Abstract: Disclosed are polymers (polyaspartic acid Zwitterionic derivatives) containing, in the molecule, 1 mol % or more of at least one repeating unit selected from the group consisting of repeating units represented by the following formulas (1) and (2). ##STR1## These polymers are useful in the preparation of hair-treating compositions and cosmetic compositions having excellent hairdressing properties and good biocompatibility.

Abstract: The present invention provides a process for the preparation of a biodegradable lactic acid-based polyester composition excellent in thermal stability, storage stability, flexibility, heat resistance, mechanical and physical properties and moldability which comprises kneading a lactic acid-based polyester and a polyester consisting of dicarboxylic acid component(s) and diol component(s) with a chelating agent, an acidic phosphoric acid ester, a molecular weight increasing agent, etc., and then devolatizing the kneaded mixture. The present invention also provides a molding process of the foregoing lactic acid-based polyester composition.

Abstract: A transparent N-alkyl-substituted maleimide/olefin copolymer composite material is provided which comprises 100 parts by weight of an N-alkyl-substituted maleimide/olefin copolymer, and 0.1 to 100 parts by weight of phyllosilicate, the phyllosilicate being dispersed uniformly and finely in a matrix of the N-alkyl-substituted maleimide/olefin copolymer. A process for producing the N-alkyl-substituted maleimide/olefin copolymer composite material is also provided. The N-alkyl-substituted maleimide/olefin copolymer composite material is excellent in transparency, heat resistance, rigidity, and dimensional stability.

Abstract: This invention relates to a coprecipitated binder composition used for the compression of pharmaceutically and agriculturally active components to provide a non-friable, readily soluble or dispersible pill or tablet. The invention also relates to the process for preparing the binder and to its incorporation in a formulation with the active ingredient.

Abstract: Polysuccinimide is produced by thermal polymerization of a precursor or a reactant admixture that includes an unsaturated compound in a plate-type reactor at temperatures sufficient to initiate polymerization and to form a brittle solid. The so-obtained polysuccinimide can be hydrolyzed to polyaspartic acidor to a polyaspartic acid salt, if desired. The precursor can be a monomer or a mixture of reactants that form polymerizable intermediates.

Abstract: The polymers according to the invention with repeating succinyl units additionally contain iminodisuccinate units.

Abstract: The present invention provide a novel polyimide which is soluble in organic solvents and excels in heat resistance, and to a process for producing the polyimide. The polyimide of the present invention comprises a repeating unit represented by the formula (1) and having a number average molecular weight of from 4,000 to 200,000. ##STR1## wherein X is --SO.sub.2 -- or --C(.dbd.O)--OCH.sub.2 CH.sub.2 O--C(.dbd.O)--, and R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are independently an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms.

Abstract: Thermosetting composition comprises a compound having in the molecule two or more carboxyl groups blocked by a vinyl ether compound, a vinyl thioether compound or a hetero compound having a vinyl type double bond and oxygen or sulfur as the hetero atom, a compound having two or more reactive functional groups which can form a chemical bond with the blocked carboxyl compound by heating, a specific vinyl ether or vinyl thioether and a thermal latent acid catalyst. The blocked carboxyl group of the first compound and the reactive functional group of the second compound may be comprised in the same molecule. The thermosetting composition gives cured products having excellent chemical properties, physical properties, weathering resistance and storage stability and is advantageously utilized for coating compositions, ink, adhesive and molded plastics.

Abstract: Copolymers of polyaspartic acid which are suitable for the Inhibition of scale deposition were obtained by reacting maleic acid, an additional polycarboxylic acid and ammonia in a stoichiometric excess, at 120.degree.-350.degree. C., preferably 180.degree.-300.degree. C., to provide copolymers of polysuccinimide. In a second embodiment, a polyamine was added to the reaction mix. These intermediate polysuccinimide copolymers could then be converted to the salts of copolymers of polyaspartic acid by hydrolysis with a hydroxide.Such copolymers are useful in preventing deposition of scale from water and find applications in treating water. Other applications include scale prevention additives for detergents. In addition, such copolymers inhibit dental tartar and plaque formation.

Abstract: Synthetic, functionalized, graft copolymers of polyesters and amino acids are provided. The copolymers are formed in one embodiment by providing a linear polyester-poly(amino acid) copolymer, and reacting the amino acid groups in the linear polymer with an amino acid derivative in a polymerization reaction to form a comb-like, graft copolymer including a polyester-amino acid backbone and polyamino acid side chains extending from the amino acid groups in the backbone. The poly(amino acid) includes functional groups which permit the covalent or ionic attachment of a biological molecule to the graft copolymer. The functionalized graft copolymers can be used in a wide range of biomedical applications including tissue engineering and drug delivery.

Abstract: Reaction products of polybasic acids and amino-containing compounds, which are obtainable by heating a mixture of (a) a polybasic carboxylic acid selected from the group consisting of citric acid, isocitric acid, aconitic acid, itaconic acid and/or tartaric acid and (b) an amino-containing compound in a molar ratio of (a) to (b) of from 1:0.1 to 1:10 to at least 80.degree. C. are used as additives in low-phosphate and phosphate-free detergents and cleaning agents.

Abstract: Polymers of maleic acid may be prepared by thermally polymerizing malic acid, maleic acid or fumaric acid with less than one equivalent of ammonia. The polymers are modified by the incorporation of amines, carboxylic acids or combinations thereof. The polymers formed are excellent inhibitors of alkaline earth salt deposition, dispersants, tartar control additives, detergent additives, and water treatment agents.

Abstract: N-containing polymers having repeating succinyl units are decolorized using activated hydrogen.

Abstract: Disclosed are methods of producing super absorbing polymeric networks of polyaspartates from crosslinked polysuccinimide. In one preferred method aspect, polysuccinimide is first reacted with an organic crosslinking agent, preferably an organic base containing at least two primary amine groups to form crosslinked polysuccinimide. The crosslinked polysuccinimide is then hydrolyzed to a polymeric network of polyaspartate which demonstrates super absorbing capability in water and in saline solution. Alternative method aspects are disclosed in which super absorbing polymeric networks of polyaspartates are produced in a single reaction vessel by sequentially crosslinking polysuccinimide with organic crosslinking agent in an aqueous reaction mixture and then hydrolyzing the reaction product to produce a polymeric network of polyaspartate.

Abstract: A method for producing polysuccinimide is provided. Thermal polymerization of maleamic acid at a temperature of from about 160.degree. C. to about 330.degree. C. produces polysuccinimide. The reaction is optionally conducted in the presence of one or more processing aids, solvents or diluents. The polysuccinimide is particularly useful as a detergent additive.

Abstract: Polysuccinimide, polyaspartic acid and salts of polyaspartic acid may be prepared by means of heating aspartic acid in the presence of sodium bisulfate. The molecular weight of the polymers may be increased from that obtained without the use of sodium bisulfate. The polysuccinimide, polyaspartic acid or salt of polyaspartic acid obtained have low color. Polyaspartic acid may be obtained in this manner directly from the effluent of an immobilized cell or enzyme column which catalyzes the production of L-aspartic acid without the necessity of intermediate isolation steps.

Abstract: Polyaspartate, useful for inhibition of incrustations due to materials causing hardness in water and of value in detergent formulations, can be prepared by reacting malic acid, maleic acid or fumaric acid with ammonia, in a molar ratio of 1:1-2.1 at temperatures greater than 140.degree. C., followed by conversion of the polysuccinimide formed in this reaction to a salt of polyaspartic acid by basic hydrolysis.

Abstract: The invention relates to a dendritic macromolecule comprising a core and branches emanating from the core wherein the branches are based on vinyl cyanide and/or fumaryl dinatrile units. The invention also relates to processes for preparing these dendritic macromolecules. The dendritic macromolecules according to the invention are not sensitive to degradation through hydrolysis reactions and are also very stable at a high temperature. The processes are very suitable for large scale production of the dendritic macromolecules without requiring purification of reaction intermediates.

Abstract: The present invention relates to a rubber composition containing silica reinforcement and to pneumatic tires having treads comprised of such rubber composition.A rubber composition comprises at least one elastomer, silica, carbon black and a silica coupler comprised of 3,3'-tetrathiodipropionitrile polysulfide mixture.

Abstract: Described herein is a composition comprising an epoxy resin containing at least one glycidyl amine group wherein the resin contains three or more epoxide groups per molecule and a particular aromatic amine hardener. These compositions possess the necessary balance of properties required for making prepreg and afford unreinforced castings with high moduli and strength.

Abstract: The present invention describes a new aliphatic polyoxaesters that is bioabsorbable and may be used to produce surgical devices such as sutures, sutures with attached needles, molded devices, and the like. The invention also contemplates a process for producing these polyesters. The aliphatic polyoxaesters of the present invention have a first divalent repeating unit of formula I:[O--C(O)--C(R.sub.1) (R.sub.2)--O--(R.sub.3)--O--C(R.sub.1)(R.sub.2)--C(O)--] Iand a second repeating unit of the formula:[--O--R.sub.12 --].sub.U, XVIand optionally a third repeating unit with a formula selected from the group consisting of:[--O--R.sub.4 --].sub.A, II[--O--R.sub.5 --C(O)--].sub.B, III([--O--R.sub.5 --C(O)].sub.P,--O--).sub.L G XIand combinations thereof wherein R.sub.12 contains an internal amine or internal amide group.

Abstract: In a process for the continuous preparation of polymers with repeating succinyl units, maleic anhydride or a derivative thereof as educt A is mixed with ammonia or an ammonia-producing compound or amides of carbonic acid as educt B and in a first reaction stage these are reacted to give an N-containing low molecular derivative of maleic acid. This derivative is then polymerized in a subsequent second reaction stage. Reaction of the educts (A,B) takes place largely adiabatically in the first reaction stage. The heat of reaction thereby released is used to take the reaction mixture to the polymerization temperature and in the second reaction stage at least partially to polymerize the N-containing low molecular derivative to obtain a polymer with repeating succinyl units.

Abstract: A biodegradable copolyester having an average molecular weight of at least 50,000 produced by copolymerizing a lactic acid component as the main component with PEG, an aliphatic polyester or a sulfo group-containing ester-forming compound, a molded article produced using it, such as a conjugate fiber, and a process for producing the molded article.

Abstract: An adhesive composition is here disclosed which comprises a 2-cyanoacrylate and at least one of compounds (a) and (b):(a) an addition reaction product of an epoxy group and a compound having a cyano group and a carboxylic acid group in its molecule, and(b) a compound having a cyano group and a carboxylic acid group in its molecule. A process for preparing the adhesive composition is also disclosed herein. According to the present invention, the 2-cyanoacrylate-based adhesive composition can be obtained which is excellent in storage stability and hardening properties of thick films and which has a high hardening rate and remarkably improved surface hardening properties of the adhesive composition itself bulged from between adherends. Particularly, the 2-cyanoacrylate bulged from between the adherends can harden rapidly, so that the vaporization of the 2-cyanoacrylate can be minimized.

Abstract: Copolymers of polyaspartic acid which are suitable for the inhibition of scale deposition were obtained by reacting maleic acid, an additional polycarboxylic acid and ammonia in a stoichiometric excess, at 120.degree.-350.degree. C., preferably 180.degree.-300.degree. C., to provide copolymers of polysuccinimide. In a second embodiment, a polyamine was added to the reaction mix. These intermediate polysuccinimide copolymers could then be converted to the salts of copolymers of polyaspartic acid by hydrolysis with a hydroxide.Such copolymers are useful in preventing deposition of scale from water and find applications in treating water. Other applications include scale prevention additives for detergents. In addition, such copolymers inhibit dental tartar and plaque formation.

Abstract: A process for preparing a polyhydroxystyrene having a novolak type structure which comprises the step of polymerizing a mixture of carboxylic acid and at least one substituted phenyl carbinol whose formula is: ##STR1## wherein (a) R.sub.1 is selected from the group consisting of H, alkyl C.sub.1 -C.sub.20, substituted and unsubstituted phenyl, and C(O)R.sub.8 (where R.sub.8 is alkyl C.sub.1 -C.sub.20); (b) R.sub.2 is selected from the group consisting of H and alkyl C.sub.1 -C.sub.20 ; and (c) R.sub.3 -R.sub.7 are each independently selected from the group consisting of H, alkyl C.sub.1 -C.sub.20, OR.sub.9 (where R.sub.9 is H, alkyl C.sub.1 -C.sub.20, esters thereof, or substituted and unsubstituted phenyl), halogen, BZT, nitro, or amino, with the proviso that at least one of R.sub.3 -R.sub.7 is OR.sub.9, in the presence of a suitable catalyst for a sufficient period of time and under suitable conditions of temperature and pressure to form said novolak type polymer.

Abstract: An unsaturated polyester resin and low profile additive containing diketo groups.

Abstract: The present invention relates to hyperbranched polyaspartate esters containing repeating structural units corresponding to the formula I and/or II ##STR1## The present invention also relates to a process for the preparation of these hyperbranched polyaspartate esters by self condensing, via a transesterification reaction, at least a portion of the hydroxy and ester groups of the hydroxy aspartates corresponding to the above formula at a temperature of 60.degree. to 240.degree. C. to form hyperbranched polyaspartate esters and eliminating alcohols having the formula R.sub.1 --OH and/or R.sub.2 --OH.

Abstract: The present invention relates to an acid catalyzed thermal polycondensation process for producing amino acid polymers. More specifically, amino acid polymers are produced by thermally condensing a mixture of one or more amino acids and optionally one or more polyfunctional monomers, using an acid catalyst, while maintaining an intimate admixture. Processing techniques useful for maintaining an intimate admixture include adding to the mixture one or more processing aids, using mechanical means, and combinations thereof. The amino acid polymers produced by this process are useful as cleaning and detergent additives; fertilizer and pesticide additives; personal care product additives; dispersants for inorganic particulates, aqueous emulsions, and drilling muds; and water treatment and oil production operation additives as corrosion and scale inhibitors.

Abstract: The present invention relates to an acid catalyzed thermal polycondensation process for producing amino acid polymers. More specifically, amino acid polymers are produced by thermally condensing a mixture of one or more amino acids and optionally one or more polyfunctional monomers, using an acid catalyst, while maintaining an intimate admixture. Processing techniques useful for maintaining an intimate admixture include adding to the mixture one or more processing aids, using mechanical means, and combinations thereof. The amino acid polymers produced by this process are useful as cleaning and detergent additives; fertilizer and pesticide additives; personal care product additives; dispersants for inorganic particulates, aqueous emulsions, and drilling muds; and water treatment and oil.

Abstract: The present invention relates to an acid catalyzed thermal polycondensation process for producing amino acid polymers. More specifically, amino acid polymers are produced by thermally condensing a mixture of one or more amino acids and optionally one or more polyfunctional monomers, using an acid catalyst, while maintaining an intimate admixture. Processing techniques useful for maintaining an intimate admixture include adding to the mixture one or more processing aids, using mechanical means, and combinations thereof. The amino acid polymers produced by this process are useful as cleaning and detergent additives; fertilizer and pesticide additives; personal care product additives; dispersants for inorganic particulates, aqueous emulsions, and drilling muds; and water treatment and oil production operation additives as corrosion and scale inhibitors.

Abstract: There is disclosed a process for preparing polysuccinimides by the thermal condensation of amino acids such as L-aspartic acid in high boiling organic reaction medium whereby a polymer is provided having highly desirable color characteristics. The organic medium is selected from high boiling alkyl alcohols having from 7 to 14 carbon atoms such as isodecanol and high boiling alkanes having from 10 to 20 carbon atoms such as dodecane. The organic medium can be employed in conjunction with acid catalysts for the condensation reaction and can be easily recovered for reuse with little or no need for purification.