Patent GB-766819-A (GB)
Title: Modified aminoplast resinous condensation products
IPC: C08G12/46
Filed: 1954-04-07
Abstract: A substance conventionally employed in aminoplast production, e.g. urea, thiourea, dicyandiamide, guanamines, guanides, or aminotriazines is condensed with an aldehyde and 0.1-25 per cent by weight of a polymer of molecular weight at least 10,000 containing carboxylic acid and carboxylic acid amide groups or a salt thereof. The polymer contains 1-15 per cent by weight of nitrogen.  It may be added to an intermediate aminoplast condensate.  Formaldehyde is preferred.  Acetaldehyde, butyraldehyde, heptaldehyde, benzaldehyde, furfural and alkoxy aldehydes are also mentioned.  Polymers mentioned are those of monomers containing acid groups and amide groups or nitrile groups which on hydrolysis yield acid and amide groups. Monomers mentioned are acrylonitrile, methacrylonitrile, a mixture of acrylic acid and acrylamide.  Alternatively acrylic acid or an a -substituted acrylic acid may be polymerized and partially amidated or a vinyl or vinylidene monomer may be copolymerized with an unsaturated acid, e.g. maleic acid and the copolymer partially amidated, or a terpolymer of a vinyl or vinylidene monomer, an unsaturated acid and an unsaturated amide may be formed.  If a nitrile-containing polymer is hydrolysed the product will generally be sodium salts which may be used directly, as may also other alkali metal, alkaline earth metal or ammonium salts. The products may be water-soluble or if condensation is carried further water-dispersible.  The products are thermosetting.  They may be modified with conventional materials, e.g. alcohols, phenols or aryl sulphonamides and the condensates compounded with usual additives, e.g. pigments, lubricants, dyes, fillers and natural or synthetic resins, e.g. alkyds.  In examples: (I) melamine and formalin are refluxed at pH 8-9.  The sodium salt of a partially hydrolized polyacrylonitrile with a molecular weight of 70,000 is then added and refluxing continued.  Dehydration yields a partially water-soluble, fusible, white powder which may be cured at 100-250 DEG  C.; (II) is similar with urea in place of melamine.  Mixed with wood flour the product yields a moulding powder; (III) is similar to (II) the product being a clear syrup which may be applied to glass, metal, regenerated cellulose tape, paper or textile fabric to form a smooth, non-tacky film thereon. Moistening with water makes the film tacky so that it may be cemented to other material to make a laminate; (IV) is similar to (I), para-toluenesulphonamide being used as a modifying agent, the product being reacted with glyceryl mono-ricinoleate and dispersed in water to yield a latex suitable for application to cellulosic material, e.g. paper or textiles.  Dried, the latex yields a re-dispersible powder; (V) the latex of Example (IV) is mixed with cellulose fibres felted on a preform and moulded to form a tray; (VI) melamine and phenylmelamine are used, and a partially hydrolysed polyacrylonitrile with a mol. weight of 80,000.  The condensate is refluxed with sodium oleate and dispersed in water; (VII) an amidated isobutylenemaleic anhydride copolymer is used; (VIII) a partially hydrolysed polyacrylonitrile is heated with an aqueous solution of a partial butyl ether of methylol melamine to yield a coating composition.ALSO:Thermosetting aminoplasts modified with a high molecular weight polymer containing carboxylic acid and carbonamide groups (see Group IV(a)) are used as sizing agents for textile materials or cellulosic fibres.  In Example IV melamine formaldehyde and para-toluene sulphonamide are condensed and the product reacted with the sodium salt of a partially hydrolysed polyacrylonitrile having a molecular weight of 70,000 and a nitrogen content of 2.5 per cent.  The product is emulsified with glyceryl monoricinoleate and the resulting latex used for sizing textile fabrics which are rendered substantially shrinkproof.