| 摘要 |
Organic materials, chiefly fibrous materials are bleached by hydrogen peroxide in a bath in which the pH value is kept below 7 by the addition of an aliphatic acid, in the absence of free sulphuric, nitric or hydrochloric acid. Sulphuric acid may however be used indirectly in that it may be added to the bath together with a salt which is converted in the presence of the acid so that an aliphatic acid is produced, together with a sulphate. Acids which may be used are oxalic acid, formic acid, cetyl alcohol sulphonic acid, stearyl alcohol phosphoric acid, and oleylaminomethane sulphonic acid. Oxydases and other enzymes may be added as activators, and softness may be imparted to the products by protective colloids such as glue or tanning matter. The feel may be improved by a pretreatment with aldehydes. The bleaching process is not limited to fibrous materials but may also be applied to horn, bone, resin, artificial resin, legumes, maize flour, and the like. It is stated that the advantage of using an aliphatic acid is to reduce yellowing of the product and in the case of textiles to result in less weakening of the fibres than is the case with other acids. The bleaching may be effected in a series of baths of increasing strength, and the bleaching liquor may be continuously pumped through the bleaching tank and kept up to strength by the continuous or intermittent addition of ingredients. Two examples are given in which oxalic acid is the aliphatic acid used. Specifications 28115/97, [Class 15], 362,352, and 404,019 are referred to. The Specification as open to inspection under Sect. 91 includes subject-matter contained in Specification 37083/34 (as open to inspection under Sect. 91). This subject-matter does not appear in the Specification as accepted.ALSO:Organic materials including fibres, horn, bone, resin, artificial resin, legumes, maize, flour, and the like are bleached by hydrogen peroxide in a bath in which the pH value is kept below 7 by the addition of an aliphatic acid, in the absence of free sulphuric, nitric or hydrochloric acid. Sulphuric acid may however be used indirectly in that it may be added to the bath together with a salt which is converted in the presence of the acid so that an aliphatic acid is produced together with a sulphate. Acids which may be used are oxalic acid, formic acid, cetyl alcohol sulphonic acid, stearyl alcohol phosphoric acid, and oleyl-aminomethane sulphonic acid. Oxidases and other enzymes may be added as activators, and softness may be imparted to the products by protective colloids such as glue or tanning matter. It is stated that the advantage of using an aliphatic acid is to reduce the yellowing of the product. Specifications 28115/97, [Class 15], and 362,352 and 404,019, [both in Group IV], are referred to. |
