“the chemistry of textiles” vivimed labs europe ltd
TRANSCRIPT
“The Chemistry Of Textiles”
Vivimed Labs Europe LtdPhotochromic Colorants
SCI Headquarters, London17th November 2011
Dr. Andy Towns
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Vivimed Labs Europe Ltd
• Then…–1840s
• Company started life as James Robinson• Natural dyes traded such as logwood– mid to late 20th centuryy
• Rise and fall of sulphur dye business • Moved into:
– hair dyesy– photographic chemicals– fluorescent colorants– fuel markers• Now…
21st century– 21st century• Growth of photochromic dye business• Change of ownership (2008) and name (2010)
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Colorants
•• Hair colorantsHair colorants
•• Photochromic dyesPhotochromic dyesyy
•• SemiconductorsSemiconductors
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Hair Coloration: “Low Temperature Fibre Dyeing”
Wool and hair are both protein fibres but…
Wool• Traditionally dyed with:
Hair• Conditions restricted:
p
Traditionally dyed with:– acid dyes
• applied at boil• typically pH <4
Conditions restricted:– temperature– pH– timetypically pH 4
– chrome and mordant dyes• often as per acid dyes• heavy metals
– liquor ratio• Performance required:
– limited pre-treatment
– reactive dyes• fixation usually at the boil
• Processes all >1hr
– intensity– level coloration
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Hair Coloration: The Challenge
Cortex
Cuticle
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Hair Coloration: The Solutions
TemporaryTemporary
SemiSemi permanentpermanentSemiSemi--permanentpermanent
PermanentPermanent
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Temporary Hair Dyes: Properties
• Relatively large cationic dyes• Similar to ‘basic’ dyes for acrylic fibre• Some even re-purposed textile dyes• Ad b d t h i fib• Adsorbed to hair fibre• Application in 5 minutes• Used in:Used in:
– shampoos– conditioners– mousses
• Lasts 1-2 washes
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Temporary Hair DyesTemporary Hair Dyes: Chromophores
OHN
NOMe
OH
N+
NN
H
NN
O
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Me3N+Me
Semi Permanent DyesSemi-Permanent Hair Dyes: Mechanism
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Semi-Permanent Hair Dyes: Properties
NHCH CH OHNHCH2CH2OHNO2
N(CH2CH2OH)2
NHCH2CH2OHNONO2
Up to 8-10 washes
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NH2
Permanent Hair Dyes: Mechanism and Properties
• Three main components:– primary intermediates (oxidation bases)– couplers– oxidant
• Reactive system:– components mixed– couplers and primary intermediates diffuse into hair fibresp p y– primary intermediates oxidised– couplers react with oxidised primary intermediates to form colorants
• Process typically takes 20-40minProcess typically takes 20 40min• Colorants relatively large in size:
– slow to diffuse out of hair fibrecoloration permanent
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– coloration permanent
Permanent (oxidation) dyesPermanent hair dyes - Oxidative Dye ChemistryPermanent Hair Dyes: Chromophores
NH2 NH2
NH2 NH
NH2
NH2
NH2
N
NH2
NH+
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2 NH2
Photochromic Dyes
Applications
• Non-textileo e e– Ophthalmic lenses– Plastics– Security printing
T til• Textile– Yarn– Screen printing– Accessories
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Photochromism: Definition
Photochromism
• “A reversible colour change induced in a compound driven in one or both directions by the action of electromagnetic radiation”
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Photochromism: Types of Dye
• T-type • P-type
– spiropyran – fulgide
– spironaphthoxazine
naphthopyran
– diarylethene
– naphthopyran
most commercially important
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Photochromism: Commercial Dyes
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Photochromism: Mechanism
NMe Me Me MeUV
ONR
l l
NR
N
O
l d
heat and/orlight
colourlessspironaphthoxazine
colouredphotomerocyanine dye
Exclusively thermal fade : ‘T-type’ photochromism
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Photochromism: Mechanism
UVUVUVUV
ΔΔΔΔ
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Photochromism: Commercial Dyes
X
O Y
X Y Z l
z
X Y Z colour
H H H weak yellow
H H amino strong yellow
OMe OMe H eak orangeOMe OMe H weak orange
OMe OMe amino strong yellow
amino H amino strong orange
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Photochromism: Neutral-coloured Dyes
major kinetic and varied to adjust
OMeMeO
major kinetic andcolour effects
X Y
varied to adjustcolour & kinetics
O OR2N
Me
Me
2
z
selected toconfers extramajor kinetic and
minor colour effectsselected to
tune kineticspeak andneutral colour
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Photochromism: Limitations
• Medium– certain polymerscertain polymers
• Photostability– use of additives
• Mixtures– activation– fatigue– fatigue
• Application method– mass coloration– screen printing
• Reversibility
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Shade DevelopmentSemiconductor Dyes: Textile Applications
• Wearable devices– genuinely smart fabrics– integration of existing technologies
• Organic semiconductorsOrganic semiconductors– flexible substrates– printable circuitry
Organic ThinOrganic ThinFilm Transistors
(OTFT)itechfuture.com
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itechfuture.com
Semiconductors: Functional Colorants
OOO
OO
gate
OTFTO
Si(R)3drain
3 source
substrate
Si(R)3
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Si(R)3
Further Information
• Photochromic dyes– Corns Partington and Towns “Industrial Organic PhotochromicCorns, Partington and Towns, Industrial Organic Photochromic
Dyes”, Coloration Technology 125 (2009) 249-261
• Hair colorants– Morel and Christie, “Current Trends in the Chemistry of
Permanent Hair Dyeing”, Chem. Rev. 111 (2011) 2537-2561
• Organic electronicsg– Anthony, “Functionalised Acenes and Heteroacenes for Organic
Electronics”, Chem. Rev. 106 (2006) 5028-5048
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