Patent GB-562977-A (GB)
Title: Improvements in or relating to methods of reducing the tendency of wool and wool-containing fabrics to felt and shrink
IPC: D06M13/368
Filed: 1942-08-18
Abstract: The tendency of wool and wool-containing fabrics to felt and shrink is reduced by treating with a dispersion or solution of an alkylated methylol melamine, and curing the alkylated methylol melamine in the wool material by the application of heat.  The temperature of curing may be 200 DEG -300 DEG  F.  The wool may be in the form of unwoven fibres or yarns, or worsteds, flannels, blankets, shirting, knitted goods, or felts, and it may be mixed with other fibres such as silk, rayon, regenerated silk, or cotton.  Water, alcohol, or aqueous alcohol may be used as the solvent or dispersion medium for the alkylated methylol melamine.  When treating a fabric, it may first be cleaned to remove fats and oils.  The dry fabric is then immersed in the dispersion of alkylated methylol melamine and passed through rolls in a padder or mangle to secure uniform impregnation and to remove excess of liquid.  Alternatively, the fabric may be sprayed. Catalysts such as oxalic acid, acetic acid, hydrochloric acid, zinc chloride, di-ammonium hydrogen phosphate, methyl hydrogen pyrophosphate, and triethanolamine phthalate, may be present.  The fabric may be heat treated while held in a drying frame, or while wound on a shell, or while passing through a loop drier.  The fabric may then be treated with soap solution.  Undyed materials, or materials dyed with, e.g. acid or chrome dyes, may be treated.  The alkylated methylol melamines may be obtained by known methods. Methylol melamine may be obtained by reacting 2-6 mols. of formaldehyde with 1 mol. of melamine.  In an example, 960 parts of formalin (37 per cent CH2O) and 252 parts melamine are heated under reflux to 62 DEG  C. and the pH is adjusted to 7.5 by addition of alkali.  After further heating the pressure is reduced and water is evaporated from the mixture.  The pressure is restored and then 1,000 parts of methyl alcohol containing phosphoric acid to neutralize the alkali is added.  The mixture at pH 6.4 is heated to distil off a mixture of methanol and water, anhydrous methanol being added continuously.  The resin solution is then concentrated under reduced pressure.  The product is readily dispersible in water.  The reaction product may be heated with other primary alcohols to obtain by interchange any desired alkylated product. Alcohols which may be used include ethyl, propyl, butyl, amyl, octyl, lauryl alcohol, ethylene glycol, diethylene glycol, propylene glycol, glycerol, pentaerythritol, and mono-ethers of di-ethylene glycol.  The process may be modified by applying to-the wool a dispersion of methylol melamine in a primary alcohol, such as methyl, butyl, or octyl alcohol, and heating so that a substantial amount of alkylated methylolmelamine is formed in situ.  In an example, 600 parts of a 50 per cent solution of methylated methylol-melamine and 160 parts of mono-butyl ether of diethylene glycol are heated together and concentrated to 408 parts of a product comprising 75 per cent of the butyl ether of diethylene glycol-reacted methylol-melamine.