Abstract: A polyacetal resin composition. An aliphatic polycarboxylic acid having four or more carbons and two or more carboxyl groups and a hindered-phenol antioxidant are incorporated into a polyacetal copolymer obtained by copolymerizing trioxane as a major monomer with a cyclic ether and/or cyclic formal each having at least one carbon-carbon bond as a comonomer using a specific heteropoly acid as a polymerization catalyst, adding, to the resultant reaction product, a compound which is any of the carbonates, hydrogen carbonates, and carboxylates of alkali metal elements or alkaline-earth metal elements, the hydrates of these, and the hydroxides of alkali metal elements or alkaline-earth metal elements, and melt-kneading the mixture to deactivate the polymerization catalyst.

Abstract: The present invention relates to new high-functionality, highly branched or hyperbranched polylysines, to processes for preparing them, and to their use.

Abstract: The present invention relates to new high-functionality, highly branched or hyperbranched polylysines, to processes for preparing them, and to their use.

Abstract: A polyoxymethylene copolymer which is a polyoxymethylene copolymer obtained by copolymerizing trioxane and 8 to 20 mol, per 100 mol of the trioxane, of 1,3-dioxolane and which (i) has a crystallization time period of 10 to 2,000 seconds at 143° C., (ii) withstands 30 to 1,000 cycles of a bending durability test and (iii) has residence heat stability for 40 minutes or more, and a molded article formed of the copolymer. According to the present invention, there can be provided a polyoxymethylene copolymer excellent in bending durability and heat stability and excellent in moldability, and a molded article formed thereof.

Abstract: To provide a resin material in which various properties of a polyacetal resin such as excellent appearance, slidability and thermal stability are maintained and a rigidity is improved as well. That is, a polyacetal copolymer which is prepared by a copolymerization of 100 parts by weight of trioxane (A), 0.0005 to 2 parts by weight of the component (B), which is a compound (B-1) having at least three glycidyl groups in the molecule or a compound (B-2) having at least two epoxy groups in the molecule, and 0 to 20 parts by weight of a cyclic ether compound (C) copolymerizable with trioxane, and which has a total terminal group amount of 15 to 150 mmol/kg, when (B) is (B-2).

Abstract: A particularly useful process which includes the steps of providing a feedstream comprising a soluble condensation promoting component capable of activating a heterogeneous acidic catalyst and a source of formaldehyde formed by conversion of dimethyl ether in the presence of a catalyst comprising silver as an essential catalyst component; and heating the feedstream with the heterogeneous acidic catalyst in a catalytic distillation column to convert methanol and formaldehyde present to methylal and higher polyoxymethylene dimethyl ethers and to separate the methylal from the higher polyoxymethylene dimethyl ethers is disclosed. Advantageously, methylal and higher polyoxymethylene dimethyl ethers are formed and separated in a catalytic distillation column.

Abstract: A branched or crosslinked polyacetal resin is excellent in blow moldability, has impact resistances such as plane impact resistance, and the smoothness of the inner surfaces of moldings produced therefrom, and is suitable for molding, particularly blow molding. It can be produced by the bulk polymerization of (A) trioxane with (B) a cyclic ether and/or cyclic formal and (C) a polyfunctional glycidyl ether compound in the presence of (D) a cationic polymerization catalyst, a mixture prepared by mixing the cyclic ether and/or cyclic formal (B) with the polyfunctional glycidyl ether compound (C) and the cationic polymerization catalyst (D) is added to trioxane (A) to conduct the polymerization.

Abstract: A process for polymerizing oxiranes, oxetanes, oxepanes, dioxolanes, trioxanes, and tetrahydrofurans to their respective polymers by contacting them with a selected metal compound is disclosed; and also a process for depolymerizing polytetrahydrofurans to monomeric tetrahydrofurans by contacting the polymer with a selected metal compound at a temperature of about 100.degree. C. to about 250.degree. C. The catalysts may be in solution or part of a heterogeneous solid, and selected organic compounds are used as accelerators in the polymerizations. The polymeric products, some of which are novel, may be used as polyether monomers for further polymerization, as by reaction with isocyanates to produce polyurethanes, and other useful polymers. Some of the polymeric products are relatively high in molecular weight and are suitable for direct use, for instance as spandex fibers.

Abstract: A process for polymerizing oxepanes, dioxolanes, trioxanes, and tetrahydrofurans to their respective polymers by contacting them with a selected metal compound and an accelerator which is a selected vinyl ester or a selected phosphorous compound.

Abstract: Process for continuous preparation of homo- and copolyoxymethylenes with stable end groups in a homogeneous phase, in which in a tubular reactor with static mixing elements cyclic formaldehyde oligomers are polymerized in the presence of protonic acids as initiators in amounts of 0.005 to 500 ppm in a polymerization zone, in which the residence time of the reaction components in this zone is 0.1 to 10 min and in which the initiator is deactivated immediately after polymerization, there being a fluid transition between the polymerization and deactivator zones which is determined solely by the addition of deactivator, and in which, besides deactivation, stabilization of the chain ends is carried out in the presence of residual monomers, with the volatile constituents being removed from the reaction mixture in a subsequent vent unit. Stabilization is carried out in the presence of alkaline substances, either at temperatures of 150.degree. C. to 250.degree. C.

Abstract: A multi-part composition is provided which is suitable for use as an adhesive, a potting compound, a coating or a sealant. It consists of a polymerizable acrylate formulation and an activating formulation, the latter usually comprising an amine-aldehyde condensation product diluted with a liquid vinyl ether; liquid epoxides may also be included as diluents in the activating formulation.

Abstract: Fluorinated aldehydes are made by reacting a fluorinated acyl chloride with a silicon hydride in the presence of palladium. Also disclosed are fluorinated ether aldehydes and their polymers, a process for making fluorinated aldehydes polymers using titanium or aluminum alkoxide catalysts, and a process for endcapping fluorinated polymers using perfluoroallyl fluorosulfate or fluorine.

Abstract: This invention relates to a polyester comprising repeating units having the structure: ##STR1## wherein R.sup.1 is selected from the group consisting of hydrogen, alkyl having 1 to 6 carbon atoms and aryl having 6 to 10 carbon atoms and R.sup.2 is selected from the group consisting of hydrogen, alkyl having 1 to 6 carbon atoms, and aryl having 6 to 10 carbon atoms.

Abstract: A polyacetal resin composition which comprises a polyacetal resin (as component A) and one or more members selected from the group consisting of an isocyanate compound, isothiocyanate compound, and modified product thereof (as component B) in an amount of 0.1-15 wt % of the composition, said polyacetal resin composition exhibiting good adhesion properties when bonded with a curable reactive resin adhesive. The present invention also relates to a part comprising a combination of the mold consisting of the composition and the adhesive.

Abstract: A polyoxymethylene copolymer excellent in stability and mechanical properties which is comprised of oxymethylene units and oxyalkylene units and has a molecular weight of 10,000 to 200,000. The proportion of oxyalkylene units to oxymethylene units is 0.07 to 0.5% by mole and the ratio of the absorbance of terminal formate groups to that of methylene groups determined by infrared spectrophotometry is not more than 0.025. A process for producing the copolymer is also disclosed.

Abstract: Moldable compositions comprising metallic powder and/or ceramic powder, mixed an organic binder are disclosed, which comprises an ether polyamine of the formula (1) and/or a primary amine of the formula (2) : ##STR1## wherein A.sup.1 and A.sup.2 are alkylene groups or aryl-substituted alkylene groups; X.sup.1 is a residue of an active hydrogen atom-containing compound having at least 2 active hydrogen atoms; n is at least 1; m is 2-8; and X.sup.2 is an amino group represented by ##STR2## wherein R.sup.1 and R.sup.2 are hydrogen atom, alkyl groups or groups of the formula : --(A.sup.3 --O).sub.k --R.sup.3, wherein A.sup.3 is an alkylene group, R.sup.3 is hydrogen atom or an alkyl group and k is at least 1; R is hydrogen atom or an alkyl groups containing 1-30 carbon atoms, A is an alkylene group containing 1-4 carbon atoms, and r is an integer of at least 1.

Abstract: Cyclic polyoxymethylene having a number-average molecular weight of 500 to 5,000 is obtained by solid state cyclization reaction of an alkalidegradative linear oxymethylene homopolymer in the presence of a medium containing a cationic catalyst.The cyclization is effected at 10.degree. to 150.degree. C. for 1 to 500 minutes in an organic liquid medium.The reaction mixture obtained by the cyclization is treated with an alkaline medium to hydrolyze and remove away unreacted linear polyoxymethylene homopolymer, and isolate the cyclic polyoxymethylene.The product has a sharp molecular weight distribution and is useful as a resin improver.

Abstract: Curable binders obtained by simultaneous reaction ofA) urethanes or ureas,B) acrylic or methacrylic compounds containing hydroxyl groups,C) paraformaldehyde andD) if appropriate, polyols,wherein, in the case where no polyol D) is also reacted, the reaction is carried out in the presence of an acid ion exchanger, and in the case where a polyol D) is also reacted, the reaction is carried out in the presence of an acid ion exchanger or a strong acid.These binders are suitable as coating compositions which can be cured by electron beams or by UV light.

Abstract: Disclosed are novel compounds which are useful as initiators for cationically polymerizable monomers. The novel compounds comprise a carbon containing cation (e.g., trimethyloxonium) which is capable of initiating cationic polymerization and a non-nucleophilic counterion which is an at least partially fluorinated hydrocarbylsulfonato metallate (e.g. perfluoroethylsulfonato-aluminate). The disclosed initiators are capable of initiating the cationic polymerization of a wide variety of monomers such as epoxides, tetrahydrofuans, oxazolines, vinyls, lactones, and the like.

Abstract: The present invention relates to a curable composition comprising:(A) at least one aminoplast resin; and(B) an amount effective to cure the composition of at least one catalyst selected from the group consisting of(B-1) an acid, or an anhydride, ester, ammonium salt or metal salt of the acid that is represented by one of the formulae ##STR1## (B-2) an acid, or an ester, a metal salt or ammonium salt of a sulfo compound represented by the formula: ##STR2## (B-3) an acid, or an ammonium or metal salts of a reaction product prepared by the reaction of at least one amine and sulfo compound of (B-2); and mixtures thereof;where in Formulae I and IIeach R.sub.1 and R.sub.2 is independently a hydrocarbyl, hydrocarbyloxy or hydrocaryltho group;where in Formulae I, II and IIIX.sub.1 and X.sub.2 are each independently sulfur or oxygen;R.sub.3 is a divalent hydrocaryl group,each R.sub.4 and R.sub.

Abstract: Benzyl pyridinium or ammonium salts of a non-nucleophilic anion are useful as a cationic polymerization initiator having a heat latency. A variety of resinous compositions containing this initiator is also disclosed.

Abstract: The present invention relates to copolyethers comprising copolymers of 7,oxa-bicyclo(2,2,1)heptane, and its alkyl-derivatives, with one or more single-ring or condensed-rings cycloaliphatic ethers, comprising the characteristic group; ##STR1## wherein R' is hydrogen and R" is H, a halogen, or an alkyl radical containing a small number of carbon atoms, and which may also be halogen-substituted.If the ether contains one ring only, it contains from 5 to 12 atoms in the ring, and if it contains a condensed-ring system, it contains a total number of from 10 to 18 atoms in the rings.Those copolyethers show a anisotropic behaviour in the molten state, and therefore have liquid-crystal properties.

Abstract: The present invention relates to a curable composition comprising:(A) at least one aminoplast resin; and(B) an amount effective to cure the composition of at least one catalyst which is a sulfo acid, or an anhydride, ester, ammonium salt or metal salt of the acid.The sulfo acid can be exemplified by sulfonic acids, such as 2-acrylamido-2-methylpropane sulfonic acid, or a reaction product of the sulfonic acid and a phosphorus acid or salt, such as a dihydrocarbyl phosphorodithioic acid.The catalyst allows curing of aminoplast resins to be accomplished at low temperatures, while imparting a high degree of water resistance to the cured coating.

Abstract: Highly conjugated organic polymers typically have large non-resonant electronic susceptibilities, which give the molecules unusual optical properties. To enhance these properties, "defects" are introduced into the polymer chain. Examples include light doping of the conjugated polymer and synthesis, conjugated polymers which incorporate either electron donating or accepting groups, and conjugated polymers which contains a photoexcitable species capable of reversibly transferring its electron to an acceptor. Such defects in the chain permit enhancement of the second hyperpolarizability by at least an order of magnitude.

Abstract: A process for producing oxymethylene copolymers and terpolymers is disclosed which involves the non-linear addition of gaseous formaldehyde to a cyclic ether having at least two adjacent carbon atoms (1) and, in the case of a terpolymer, to a mixture of at least one (1) and one monoethylenically unsaturated aliphatic diol formal having at least four carbon atoms in its main chain (2), or to a mixture of (1) with a (2), in the presence of a polymerization initiator at a rate controlled so as to conform to a rate determined by kinetic equations that describe the rate of decomposition of trioxane to formaldehyde during conventional copolymerization of trioxane with a cyclic ether. The process and kinetic equations of the invention are applicable to batch reactions, single stream continuous reactions and dual stream continuous reactions.

Abstract: A water-based coating composition comprising as the first component, a mixture of a polyaldehyde chosen from the group consisting of glyoxal, glutaraldehyde and derivatives of glyoxal and glutaraldehyde, and a water dispersible component chosen from the group consisting of epoxy resin emulsions which can be emulsified in water, synthetic latexes stable at about pH 7 or less, low molecular weight resin emulsions, epoxy ester emulsions, water emulsified alkyds, and cationic, anionic and non-ionic asphalt emulsions and, as the second component, the non-gel reaction product of (I) urea-formaldehyde ether monomer, urea-formaldehyde phenol monomer, urea-nonylphenol formaldehyde monomer, thiourea-formaldehyde ether monomer, melamine formaldehyde ether monomer hexamethoxymethyl melamine, with (II) a polyamine chosen from a group consisting of primary and secondary amines and/or a monoamine, combined with (III) a hydroxide or oxide of calcium, strontium or barium.

Abstract: A thermosetting resin composition is disclosed which comprises a fusible product obtained by a method including the steps of:providing a mixture which comprises (a) a raw material containing one or more condensed polynuclear aromatic compounds having at least two condensed benzene rings, (b) a crosslinking agent containing an aromatic compound having one or more aldehyde groups directly bonded to the aromatic nuclei thereof, and (c) an acid catalyst; andreacting the mixture at a temperature sufficient to effect the crosslinking of the one or more condensed polynuclear aromatic compounds, thereby to obtain the fusible product. A further heat treatment of the thermosetting resin composition gives a COPNA resin which is an infusible, insoluble, condensed, polynuclear aromatic hydrocarbon resin.

Abstract: Cationic fixing agents based on the reaction products of(a) a monofunctional or polyfunctional amine having one or more primary and/or secondary and/or tertiary amino groups and(b) cyanamide, dicyandiamide, guanidine or bisguanidinegive improved results when the reaction takes place in the presence of a catalyst (K) selected from metals, metal salts and heterocyclic nitrogen-containing organic bases, particularly zinc chloride.

Abstract: Polyurethane dispersions based on reaction products from (A) bismethylolated urethanes having at least 2 urethane groups and (B) polyhydroxyl compounds which contain groups which are capable of ion formation, these groups being present in neutralized form, and a process for the preparation thereof. The use of the dispersions for the surface-coating of metal, plastics, glass, leather and paper.

Abstract: Tricarbocyanine polymeric dyes have formulae I and II: ##STR1## where Y can be ##STR2## --S--, --Se-- or --O--, A can be ##STR3## in which R.sup.19 can be alkyl or --Cl, and p can be 0 or 1, R.sup.6 and R.sup.7 independently can be alkyl of (C.sub.1 -C.sub.30), preferably (C.sub.1 -C.sub.18),R.sup.4 and R.sup.5 independently can be --H, C.sub.6 H.sub.5 SO.sub.2 --, or CF.sub.3 SO.sub.2 --,Z can be --SO.sub.2 --, --CH.sub.2).sub.m, or vinylene,W can be I.sup.-, Br.sup.-, Cl.sup.-, ClO.sub.4.sup.-, PECHS.sup.- (polyethylcyclohexylsulfonate), F.sub.3 CSO.sub.3.sup.- (trifluoromethanesulfonate), or other commonly used dye anions,m is an integer of 1 to 20, andn is an integer of 5 to 10,000.

Abstract: Furfuryl alcohol-formaldehyde resins which can be prepared by using a water soluble multivalent metal salt as the catalyst, thereby eliminating the use of an acid catalyst and the necessary attention it requires.

Abstract: A trioxane copolymer is manufactured by adding to trioxane and a co-monomer, 0.0001 to 2.0 percent by weight, based on the total weight of the monomers, of one or more sterically hindered phenols, then co-polymerizing the resultant mixture in the presence of a cation-active catalyst, and then treating the resultant copolymer by heating it at a temperature which is higher than the melting point of the copolymer to melt the copolymer and decompose and remove unstable parts of the copolymer.

Abstract: There are provided metal containing polymeric coordination compounds which are prepared by a process which comprises reacting metal salts with polydentate ligand molecules obtained by the condensation of aromatic dialdehydes with .beta.-hydroxy-.alpha.,.gamma.-diamines. The above are electrical semiconductors. Such polymers containing platinum have a biological activity.

Abstract: A process for producing a polyacetal copolymer, which comprises copolymerizing formaldehyde and a compound selected from the group consisting of alkylene oxides, poly(alkylene oxides), cyclic formals and poly (cyclic formals) in the presence of a Lewis acid and an anionic polymerization catalyst with the exception of metal chelate compounds.

Abstract: New aromatic sulfonylsulfoxonium salts are of formula ##STR1## where q is 1 to 4,R denotes an aliphatic, cycloaliphatic, or aromatic group,R.sup.6 denotes H, an alkyl or aralkyl group, or a group --COR.sup.9, --CO--NH--(CO).sub.r --R.sup.10, or --SO.sub.2 --R.sup.11, where r is zero or 1,one, but not both, of R and R.sup.6 denoting an aromatic group,R.sup.7 denotes an alkyl, alkenyl, cycloalkyl, cycloalkylalkyl, or aralkyl group,R.sup.8 has the same meaning as R.sup.7 but may alternatively represent a dialkylamino group or, if R.sup.7 denotes alkyl, it may alternatively represent an arylamino group,R.sup.9, R.sup.10, and R.sup.11 each denote an alkyl, aryl, or aralkyl radical of 1 to 25 carbon atoms,t is 1, 2, or 3, andZ.sup.- denotes a t-valent anion of a protic acid.The salts, e.g., dimethyl-p-toluenesulfonylmethylsufoxonium hexafluorophosphate, are useful as catalysts for the polymerization of cationically polymerizable materials by means of actinic radiation and/or heat.

Abstract: This invention relates to an improved polyimide resin and to a method of its production.The improved polyimide resin is made from phenanthrene which is converted via a 9, 10-diol to oligomers of diphenic anhydride units linked by keto bridges. The oligomers are reacted with from 0.1 to 0.6 of an equivalent quantity of an aromatic primary diamine. The remaining anhydride groups are reacted with a monofunctional amine to give a polyimide of low cross-link density.The resin will find use for instance in forming glasscloth laminates.

Abstract: This invention relates to thermally stable resins and provides such a resin made from cheaply available coal-derived materials, whereas presently available resins are made from increasingly expensive oil-derived materials.The resin comprises the condensation product of a reaction between an aromatic diamine and a phenanthrene-formaldehyde reaction product, which product has been oxidized to produce keto groups bridging the phenanthrene moieties and carboxy groups. The condensation product is a poly-(amine-imide).The invention also includes a method of making the resin and varnishes containing the resin.The resin will find use for instance as a high temperature insulator or in glass or asbestos laminates in compressor blades.

Abstract: A polyacetal suitable for moldings which are excellent in lubricity, wear and antistatic properties, which has at least one terminal of its linear polymer molecule capped with an alkylene oxide adduct of an alcohol or a carboxylic acid, which adduct is of the formula ##STR1## wherein R.sub.o is a hydrogen atom, alkyl group, substituted alkyl group, aryl group, or substituted aryl group, R.sub.o 's may be the same or different, R.sub.1 is an alkyl group, substituted alkyl group, aryl group, or substituted aryl group, R.sub.2 is a hydrogen atom, alkyl group, substituted alkyl group, aryl group, or substituted aryl group, m is from 2 to 6, and n is from 1 to 1,000; the number average molecular weight of said polyacetal being in the range from 10,000 to 500,000 excluding the terminal group.

Abstract: A polyimide resin is made by converting a phanthrene to its 9, 10 diol derivative, reacting the derivative with formaldehyde to give a methylene bridged reaction product, oxidizing the reaction product to produce a polycarboxylated product, and reacting the polycarboxylated product with an aromatic diamine to form the polyimide resin. The invention also includes the resin, the reaction product and the polycarboxylated product.The resin will be useful as a lamp capping cement, a high temperature insulator, in copper clad printed circuit boards, in glass or asbestos laminates for use as compressor blades.

Abstract: Undesirable deposition of polyoxymethylene onto the inner wall of a polymerization reactor and onto a stirrer, which deposition is observed in the slurry polymerization of formaldehyde carried out in an inert organic liquid medium, can be minimized by carrying out the slurry polymerization in the presence of a polymerization catalyst prepared by bringing a metal chelate compound into contact with polyoxymethylene in an inert organic liquid medium in the presence of formaldehyde. Preferably, the slurry polymerization is carried out in the presence of, in addition to the above-mentioned polymerization catalyst, at least one polyvalent metal salt of an alkylsalicylic acid or of a dialkyl ester of sulfosuccinic acid. It is also preferable to use a tubular closed loop reactor equipped with an impeller wherein gaseous formaldehyde is blown into the reactor in a position located downstream from the impeller, while the catalyst-containing slurry is circulated therethrough.

Abstract: This invention relates to thermally stable resins and provides such a resin made from cheaply available coal-derived materials, whereas presently available resins are made from increasingly expensive oil-derived materials.The resin comprises the condensation product of a reaction between an aromatic diamine and a phenanthrene-formaldehyde reaction product, which product has been oxidized to produce keto groups bridging the phenanthrene moieties and carboxy groups. The condensation product is a poly-(amide-imide).The invention also includes a method of making the resin and varnishes containing the resin.The resin will find use for instance as a high temperature insulator or in glass or asbestos laminates in compressor blades.

Abstract: Cationically polymerizable compounds, for example cyclic ethers, can be thermally polymerised if an aromatic iodonium salt of the formula I[(Ar.sup.1)(Ar.sup.2)I].sup.+ [MX.sub.n ].sup.- (I)in which Ar.sup.1 Ar.sup.2, M, X and n are as defined in claim 1, is used as the catalyst and an agent which forms free radicals on heating and has the formula III or IV ##STR1## in which R.sup.2, R.sup.3, R.sup.5, R.sup.6, R.sup.8 and m are as defined in claim 1, for example a benzpinacol silyl ether, is used as the co-catalyst. The process is of particular importance for heat-curing epoxide resins as a one-component system.

Abstract: Undesirable deposition of polyoxymethylene onto the inner wall of a polymerization vessel and onto a stirrer, which deposition is observed in the slurry polymerization of formaldehyde carried out in an inert organic liquid medium in the presence of a polymerization catalyst, can be minimized by carrying out the slurry polymerization in the presence of at least one polyvalent metal salt selected from polyvalent metal salts of alkylsalicylic acids and polyvalent metal salts of dialkyl esters of sulfosuccinic acid. Optionally, a polyethylene glycol monoether may be used in addition to the polyvalent metal salt.

Abstract: A process for the anionic polymerization or copolymerization of olefinic monomers, dienic monomers, vinyl monomers and heterocyclic monomers is described which comprises reacting at least one monomer which is an olefinic monomer, a vinyl monomer or an heterocyclic monomer with a catalyst capable of inducing anionic polymerization and an aprotic macroheterocyclic cryptant, said at least one monomer being the only medium for the reaction.The macroheterocyclic complexing agent has general formula ##STR1## in which: R.sub.1 is hydrogen, a hydrocarbon radical or alkoxycarbonyl, or the two R.sub.1 together can form a group of the general formula: ##STR2## in which A is a hydrocarbon radical,D is oxygen, sulfur, or a hydrocarbon radical, with the proviso that at leat two of the D groups are oxygen or sulfur and that if R.sub.1 is hydrogen, a hydrocarbon radical or alkoxycarbonyl, one of these two D groups is oxygen or sulfur and the other is oxygen, andn and p are integers from 1 to 3 and m is 2 or 3.

Abstract: The present invention relates to a method for the manufacture of an improved ureaform fertilizer. The method consists in the condensation of urea and formaldehyde carried out in a controlled system having a pH between 3.5 and 4.2 wherein the overall concentration of the reagents is in the range of 20 to 40% by weight. The ratio between the reagents is between 1.2 to 1.5 moles of urea to 1 mole of formaldehyde and the temperature of the reaction is kept between 15.degree. C. to 40.degree. C. Examples of preferred controlled systems are H.sub.3 PO.sub.4 -KH.sub.2 PO.sub.4 and H.sub.3 PO.sub.4 -NH.sub.4 H.sub.2 PO.sub.4. The method can also be performed in a continuous manner giving rise to an overall quantitative yield, and being temperature self-regulating.The ureaform obtained by the method has an activity index of over 75 and excellent physical properties.