| 摘要 |
<p>1,272,302. Polyaminoacid coating. M. S. M. LEFEBVRE. 22 Jan., 1969 [22 Jan., 1968; 6 Dec., 1968], No. 3556/69. Heading B2E. [Also in Division C3] A poly(aminoacid) is treated with a solution comprising a hydrogen halide in a mixture of water and alcohol at a concentration which effects a depolymerisation such that the reduction of the degree of polymerisation by 50% takes more than a minute and in a quantity sufficient to take all the partially depolymerised polyamide into solution, and the resulting solution is then neutralised with an alkali to form a precipitate. Preferably the solution is allowed to stand for about a day before neutralisation. A softening agent e.g. polyoxyethylene sulphonate or menthol or other phenol may be mixed with the solution or neutralising agent. Precipitation may be effected in the presence of a filler, e.g. rare earth oxides, or in situ on a fabric. In the case of nylon 6 HCl at a concentration exceeding 2 moles/litre may be used. The precipitation product is stated to have ionic sites which cause reticulation giving a cellular product having very different electrostatic properties from the starting polyamide. Uses. The application of the process with neutralisation effected in situ on a fabric is stated to improve opacity, moisture-absorbance and fire-resistance and to modify the dyeing properties. A further treatment with aqueous sodium bicarbonate forms bubbles in the coating and give a simulated leather appearance. Polymer precipitates on a filler may be used for radiation-deflecting or absorbing screens. Specified fabrics are cotton, polyester and nylon. In the case of nylon contact with the solution prior to neutralisation should be brief (less than 10 and 3 seconds for nylons 66 and 6 respectively) and the fabric may first be dipped in water. The solution may be applied by doctor blade, bath or roller.</p> |
