Yeadon, United Kingdom
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Lewis D.,Perachem Ltd | Mama J.,Perachem Ltd | Hawkes J.,Perachem Ltd
Applied Spectroscopy | Year: 2014

The use of formamidine sulfinic acid in the textile industry goes back many years, particularly as an agent for the reduction or "vatting" of vat dyes, to form the water-soluble leuco species, when dyeing or printing cellulosic fibers. Many workers have labeled this agent as thiourea dioxide and theorized that its reducing power developed through the existence of two isomeric forms: thiourea dioxide (the sulfone), and formamidine sulfinate. This article has used solid and solution Fourier transform infrared (FT-IR) spectroscopy to show that the name thiourea dioxide is a misnomer since the compound does not exist in the six-valent state, but is stabilized in the four-valent state by formation of a strong internal zwitterion as shown in the article. © 2014 Society for Applied Spectroscopy.


Patent
Perachem Ltd | Date: 2013-03-22

A colouring composition comprising: (i) at least 0.0001 wt % of a water-soluble dye compound containing one or more sulfonate and/or carboxylate groups; (ii) at least 0.1 wt % urea; (iii) from 0.1 to 2.5 wt % of a thiol; (iv) less than 0.5 wt % ammonia; and (v) less than 0.5 wt % sulfite ions.


Patent
Perachem Ltd | Date: 2012-09-26

A method of removing colour from dyed hair, the method comprising applying to the hair a colour removal composition comprising a sulfur-containing nucleophile or a precursor thereof. The sulfur-containing nucleophile can be a salt of sulphoxylic acid, thiocyanate, thioglycolic acid, thiocarbamate, carbamoyl sulphinic acid and mixtures and/or salts thereof.


Patent
Perachem Ltd | Date: 2012-07-27

A method of removing colour from hair that has been oxidatively dyed, the method comprising the steps of: (a) contacting the hair with a composition comprising a sulfur-containing nucleophile or a precursor thereof; (b) contacting the hair with an acidic composition; and (c) contacting the hair with an oxidising composition; wherein there is no rinsing step between step (a) and step (b).


Patent
Perachem Ltd | Date: 2015-05-27

A method of treating a wool material, the method comprising the steps of:


Patent
Perachem Ltd | Date: 2012-09-26

A hair treatment method comprising the steps of:(a) optionally bleaching hair by applying a bleaching composition comprising from ammonium carbonate or a divalent metal cyanate and a source of hydrogen peroxide;(b) dyeing the hair by applying a colouring composition comprising a sulphur-containing nucleophile and a dye compound selected from a dye class other than the class of reactive dyes; and(d) removing colour from the hair by applying a colour removal composition comprising a sulfur-containing nucleophile or a precursor thereof.


Patent
Perachem Ltd | Date: 2013-10-09

A colouring composition comprising:(i) at least 0.0001 wt% of a water-soluble dye compound containing one or more sulfonate and/or carboxylate groups;(ii) at least 0.1 wt% urea;(iii) from 0.1 to 2.5 wt% of a thiol;(iv) less than 0.5 wt% ammonia; and(v) less than 0.5 wt% sulfite ions.


Patent
PERACHEM Ltd | Date: 2013-03-22

A method of treating a material, the method comprising the steps of: (i) contacting the material with a colouring composition comprising a dye compound; and (ii) contacting the material with a composition comprising a quaternary ammonium salt.


Patent
PERACHEM Ltd | Date: 2011-01-24

A depilatory composition comprising a source of cyanate ion, an organic acid or a salt thereof and a peroxide compound; and methods of removing hair from the skin using such compositions.


Lewis D.,Perachem Ltd | Mama J.,Perachem Ltd | Hawkes J.,Perachem Ltd
Materials | Year: 2013

This review discusses a new aspect to the safety profile of oxidative hair dyes using data already in the public domain. These dyes contain secondary amines that are capable of forming potentially carcinogenic nitrosamine derivatives when exposed to atmospheric pollution. Numerous scientific articles confirm the existence of secondary amines in hair dyes (and their intermediates), the possibility of nitrosation by atmospheric NOx of secondary amines to give the N-nitrosamines, and the significant safety risks on N-nitrosamines. It is believed that such nitrosamine derivatives should be investigated more fully in the interests of consumer safety. © 2013 by the authors.

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