Weighting silk

Stannic chloride, SnCLp a fuming liquid, is used in the preparation of organic compounds and chemicals to weight silk and to stabilize perfumes and colors in soap. 

Some compounds of tin are used as fungicides and insecticides. Tin is also used for weighting silk, to give the fabric more body and heft. 

Iron(lll) nitrate is used as a mordant for dyeing black and buff. Other applications are in tanning weighting silks and in preparation of analytical standards. 

Tin(lV) chloride is a mordant for dying fabrics a stabihzer for perfume in soap used in weighting silk in ceramic coatings in manufacturing blue print papers and to produce fuchsin. Also, tin(IV) chloride is used in preparing many organotin compounds. 

For heavily weighted silk, other treatment may also be used (see p. 460). 

Microscopically, weighted silk is distinguished especially by its greater diameter, while sometimes the incrustations of the added weighting material may be observed. Further it is easy to see the disaggregation of the silk into the separate fibrils constituting the filament of fibroin. If it is desired to eliminate these weighting materials in order to observe the fibre better under the microscope, the silk is treated iu the manner indicated later (see p. 460). 

When brought near to a flame, natural (ordinary and wild or tussah) silk bums with an odour of burnt hom and leaves a spongy carbonaceous residue (except with heavily weighted silk) artificial silks with a cellulose basis bum rapidly, almost without odour or residue, while " strengthened " 1 silks leave an ash in the form of the fibre artificial silks with a gelatine basis (A. Millar s silk, Vandura silk) bum like animal fibres. 

A portion of the sample is immersed in the cold in concentrated hydrochloric acid or in sulphuric acid of 58° Baumd ordinary non-weighted, natural silk dissolves readily, heavily weighted silk and wild natural silk more slowly artificial silks dissolve after some time, those with a gelatine basis first softening and then dissolving in about two hours. 

In this case the heating on the water-bath is prolonged to half an hour since, especially with fabrics containing either heavily weighted silk or wild (tussah) silk, the dissolution of this in potash takes place more slowly than with wool. 

With weighted silk dyed black it is necessary to prolong the immersion to ij minute and with wild silk to 2-3 minutes. The zinc chlondc may be replaced by Lowe s solution, m which the fabric is immersed completely for about 2-3 hours in the cold. A better plan consists in making two determinations, one with zinc chloride and the other with Ldwe s solution. 

For black weighted silk the coefficient 13-64 is used and for white or coloured weighted silk, 9-89. 

Light and SEM images of the weighted silk specimen were compared to other specimens that were not weighted. No obvious distinctions were revealed, despite the presence of about 50% ash in the case of the weighted silk and only about 1% ash in other cases. 

Azo yellow is acid fast and can be used satisfactorily for dyeing tin phosphate weighted silks. It is indispensible for producing water fast yellow and brown tints. 

Technical Observations. Malachite green is still used in large quantities for coloring tin-weighted silk, wool, and paper. Pure compound shades are obtained inexpensively by using it in mixture with other dyes, but the tints are of only moderate fastness. The dye is also used in silk and cotton printing, but does not fulfill the modern demands for fastness properties so its use in these fields is declining. 

Alizarin pure blue dyes a pure blue quite similar to the color of aniline blue (triphenylrosaniline). Its color strength is high and its fight fastness is very good. It is especially valuable for tin phosphate weighted silk with which it is widely used. 

As a result of this effort, comparison standards for cotton and wool were distributed for the first time in 1914 and 1916. Then, after a long interval and contrary to the original decision, 5-degree standards were put out between 1926 and 1928 for unweighted silk, weighted silk, viscose rayon, and acetate silk. With these standards, it was possible for the first time to classify dyes in fastness groups according to a uniform system. 

Zirconium basic acetate has Isscn used for weighting silk several comtsmmls have ls en suggested ns mordants and in the preparation of hie dyes the nit rate has lsen employed ns A food preservative the hard compounds, like the carbide, make effective abrasives the dear crystalline zircon is used as a gem, the ml variety Ising known as hyacinth, the yellow is called jneinth, the white is known as jargon, the pale brown crystals from Ceylon am decolorized by hent mid ended Malum diamonds. 

USE As mordant in dyeing, weighting silks, tanning as reagent in analytical chemistry as corrosion inhibitor. 

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