Disperse dyes. Disperse Dyes and Their Application to Polyester. Fundamental behavior of dyes. Fundamental behavior of dyes

Size: px

Start display at page:

Download "Disperse dyes. Disperse Dyes and Their Application to Polyester. Fundamental behavior of dyes. Fundamental behavior of dyes"

Jessie Adams
6 years ago
Views:

Fundamental behavior of dyes Fundamental behavior of dyes - The specific reactions concerned depend on the chemical character of the fiber, and therefore choice of dye is restricted to those capable

1 Fundamental behavior of dyes Fundamental behavior of dyes - The specific reactions concerned depend on the chemical character of the fiber, and therefore choice of dye is restricted to those capable of interacting in the appropriate manner. o single class of dye can dye all fibers. A specific class of dye can only be applied to a given type of textile fiber. - nce the appropriate dye class for the fiber in question has been chosen, attention has to be turned to the substantivity of the dyes required to provide the necessary level of fastness properties. - This also involves choice of the method of application best suited to the dye combination. - It is at this stage that the classification of dyes by appropriate dyeing procedures becomes especially relevant, and these matters will now be considered in more detail Disperse dyes Disperse dyes are nonionic, have very limited solubility in water at room temperature Disperse Dyes and Their Application to Polyester They have substantivity for one or more hydrophobic fibers e.g. Polyesters, cellulose acetate and ylons. They are usually applied from a fine aqueous dispersion containing some dissolved dye. In the aqueous solution from which dyeing normally takes place, despite the low water solubility of the dye. 2 = Disperse Red = Disperse Yellow 11 12

Introduction Polyester Dyeing Mechanism Disperse Dyeing Mechanism Brown 3% Viloet range8% 8% Blue 30% - It reflects the difficulty of synthesizing green and black compounds, which

agents-------0.4g/l (1 g/l ammonium sulfate adjusted with the bath at full volume, to p 4.5-5.5 with formic acid) Anionic dispersing agent---0.

2 Introduction Polyester Dyeing Mechanism Disperse Dyeing Mechanism Brown 3% Viloet range8% 8% Blue 30% - It reflects the difficulty of synthesizing green and black compounds, which are nonionic and of small enough molecular Dye Dye solid Dye micelles size to have substantivity for and to be able to diffuse into Dispersing agent Dye dissolved (0.1mg/L) hydrophobic fibers. Dye fiber Polyester Dyeing Procedure Dyeing Recipe: Polyester Dyeing Procedure Reduction learing(r/) of dyed Polyester Disperse dye x%(owg) p Buffering agents g/l (1 g/l ammonium sulfate adjusted with the bath at full volume, to p with formic acid) Anionic dispersing agent---0.5g/l on penetrated dyes Staining Alternatively Acetic acid is frequently used to adjust the p without the addition of ammonium sulfate, although this is not a true buffer system. A general thumb rule has the starting temperature about ~ /min 130 0,60 min 3 0 /min 40 0 Penetrated dyes 80 o, 20min Wash off o staining Dye, Dispersing agent, p controlling agent, Fabric 15 16

3 Polyester Dyeing Procedure Reduction learing Recipe: austic Soda(a) g/l Sodium ydrosulfite (a 2 S 2 4 ) g/l Soaping agents g/l /min 80 0, 20min 40 0 Polyester Dyeing Procedure Principles of reduction clearing Azo dyes Reduction 2 a 2 S 2 4, a R 8 Anthraquinone dyes a + R 8 - Reduction learing xidation - a + Solubilized leuco form 2 olorless / o substantivity for PET cf. Anthraquinone dyes is partially and reversibly reduced to a soluble sodium leuco form which can be washed away hemical Structure of Disperse Dyes Disperse Dyes hemical Structure of Disperse Dyes Some of the remaining dyes are unique chemical entities and among the variety of structural type found suitable for disperse dyes are- Mono Azo Dyes The largest majority (50%) of disperse dyes are mono azo dyes of relatively low molecular weights. They contain no ionic Solubilizing groups in dye bath conditions. They may be quite strongly polar. Anthraquinoid Derivatives A significant proportion (20%)of the remaining disperse dyes are Anthraquinoid derivatives, but they are being gradually replaced (except for some bright pinks and blues) because of cost and environmental problems in manufacture. eterocyclic ompounds ewer disperse dyes are increasingly based on the use of heterocyclic compounds. 19 Benzodifuranes aphthalimides = R3 methines oumarins 2 quinophthlones nitrodiphenylamines 20

4 Mono Azo Dyes Diazo omponent = :-,- 2, Two Possibilities :-,- 2,-,-S 2 3,-Br,-l, Six Possibilities :-,- 2,-,-S 2 3,-Br,-l, Six Possibilities :-,- 3,- 3,- 2 5,- 2 5, Five Possibilities :-,- 3,- 2 5,- 3,- 2 5, Five Possibilities :-,- 3,- 2 5,- 4 9,- 2 4, - 2 4, ,Seven Possibilities :-,- 3,- 2 5,- 4 9,- 2 4, - 2 4, ,Seven Possibilities oupling omponent 21 Dye Disperse Dye ame = Mono Azo Dyes d 1 Yellow 2 range range30 2 l l Ac 4 Red Red 13 2 l Red S Ac 2 4 Ac 7 Yellow 3 Ac It does not extend to bright blues, greens or blacks. The brighter and greener shades of yellow are well covered by the heterocyclic azo and other possible chromophores. The hydroxy group imparts better light fastness to dyeing on acetate and polyester than corresponding amino group. The same hydroxy group has the reverse effect on nylon dyeings. 22 Anthraquinonoid Dyes R 8 Anthraquinonoid Dyes R 8 The hue is almost totally controlled by substituents,, and R 8 and these substituents are usually hydroxy, amino and secondary amino groups R. The substituent (R) in the secondary amino group can be: - 3,- 2 4, a benzene ring(ar), or a benzene ring which is itself substituted with a methoxy (- 3 ) group or hydroxy ethyl group 2 4 at the para position. 23 Substituents and positions have less effect on the hue of the AQ disperse dyes but can have considerable effect on the dyeing and fastness properties of the product. While yellow and orange products based on anthraquinone can be synthesized they have not proved to be competitive with yellow and orange disperse dyes based on other chromophores. As a result most surviving AQ disperse dyes are bright reds, through violets to blues. 24

5 Anthraquinonoid Dyes R 8 Dye ame R 8 1 range 2 Red Red Red 60 2 Ar 5 Violet Blue Blue ther Dye hromophores The aminoazobenzene derivatives do not extend into theareaof greenish yellows. Although they are often economical and show high extinction coefficients, they are not noted for their brightness. The derivatives of Anthraquinone suitable for bright greenish yellows can be synthesized, but there are other more cost effective alternatives because AQ dyes generally have much lower extinction coefficients than azo dyes. Benzodifuranes : Derivatives of a recently introduced heterocyclic hromophore boast a bright red disperse dye of very high extinction coefficient. ues range from yellow to blue. Benzodifuranes ther Dye hromophores ther Dye hromophores oumarins : Principally bright fluorescent yellows,.i. Disperse yellow 82. Some derivatives are used as a fluorescent brighteners. Methines : Although mainly featured in brilliant yellows,.i Disperse Yellows 49,82,92 the group includes the brightest blue disperse dye currently available. apthalimides :This group includes some brilliant, fluorescent compounds example.i Disperse Yellow 11. R3 oumarins = Methines aphthalimides itrodiphenylamines: chemically simple, economical yellows of high light fastness on polyester but of low extinction coefficient. They have poor light fastness on nylon. Quinophthalones: The unsubstituted parent compound.i Disperse Yellow 54 is a low energy dye suitable for many general applications along with.i disperse Red 60 and.i disperse Blue 56..I Disperse Yellow 64 and 67 have higher energy and have better resistance to sublimation. 2 itrodiphenylamines Quinophthalones 27 28

eterocyclic Dyes The heterocyclic diazo components and coupling components which have been used to improve the brightness and color range of mono azo disperse dyes- Azothiophenes : These range from.i. Disperse Blue 284 to the only available disperse green,.

S S = Azothiophenes = Azobenzothiazoles = R Azopyridones 29 olor and onstitution in dyes Azo Disperse Dyes = Diazo omponent oupling omponent The Diazo component side of the molecule normally contains

- 2 >->-S 2 3 >-l,-br The coupling component conventionally drawn at the right hand side, contains groups which tend to donate electrons such as the substituted amino groups,-( ).

6 eterocyclic Dyes The heterocyclic diazo components and coupling components which have been used to improve the brightness and color range of mono azo disperse dyes- Azothiophenes : These range from.i. Disperse Blue 284 to the only available disperse green,.i Disperse green 9. Azobenzohiazoles :oteworthy for scarlets through bordeaux reds which include.i disperse Reds 153,177,263. Azopyridones: ften used for bright yellows.i. Yellow 119. S S = Azothiophenes = Azobenzothiazoles = R Azopyridones 29 olor and onstitution in dyes Azo Disperse Dyes = Diazo omponent oupling omponent The Diazo component side of the molecule normally contains the groups tending to attract electrons. - 2 >->-S 2 3 >-l,-br The coupling component conventionally drawn at the right hand side, contains groups which tend to donate electrons such as the substituted amino groups,-( ). ( 3 ) 2 > - 3 >- 2 >->- 3,- 2 5,- 3, olor and onstitution in dyes Substitution Effects olor and onstitution in dyes Azo Disperse Dyes Excited State X Excited State + Yellow range = E E 1 E 2 E = hc/ ypsochro mic shift Red Bthochromic Shift (Increase in the wavelength of maximum absorption by the dye) Ground State E 1 > E 2, 1 < 2 Bathochromic shift : 장파장이동 X Ground State Ṅ. R1 31 Violet Blue Green The greater the tendency of groups at the left side of the azo group to accept electrons and the groups at the right hand side to donate electrons the further move the molecule is called Bthochromic shift. 32

7 olor and onstitution in dyes olor and onstitution in dyes Azo Disperse Dyes = Dye ame 1 Yellow 2 range range30 2 l l Ac Anthraquinone Disperse Dyes The interaction between the electron accepting groups of the chromophore itself, the two anthraquinone carbonyl groups >= and electron substituent groups in the (,,,R 8 ). Electron Donating Groups : R 8 Ar> -Alk> - 2. > - R2 4 Red Red 13 2 l Red S Ac 2 4 Ac Tertiary amines do not lead to satisfactory dye structures for they are bulky and eliminate the possibility of hydrogen bonding between adjacent amino and carbonyl groups( > -.=<). 7 Blue Br 2 5 A 2 4 Ac 2 4 Ac olor and onstitution in dyes Anthraquinone Disperse Dyes The more powerful the effect of the electron donor substituents, the more marked is the Bathochromic shift (in the direction yellow to black) while substitution in both the benzoid rings of anthraquinone,,,r 8 is more effective than substitution in only one. The appropriate substituents at the and positions canbeusedto augment desired properties of the dye molecule e.g. light fastness. Progressive substitutions of the,,,r 8 positions with and 2 groups carry the color from the orange intermediate (Quinizarin) dye=1 to the blue dye=7 with four donor groups. R 8 R2 olor and onstitution in dyes R 8 R2 Dye ame R 8 1 range 2 Red Red Red 60 2 Ar 5 Violet Blue Blue

ydrolysis of Dye Esters The chemical group frequently found in disperse dyes is an ester group, often an acetyl group, --- 3 and like the acetyl groups in cellulose acetate it is susceptible to

8 ydrolysis of Dye Esters The chemical group frequently found in disperse dyes is an ester group, often an acetyl group, and like the acetyl groups in cellulose acetate it is susceptible to hydrolysis in neutral and alkaline conditions: Dye Dye The products are acetic acid and a different azo disperse dye whose color may be quite different from that of the parent dye. Usually the wavelength of maximum light absorption is shifted to a longer wavelength (Bathochromic shift) The p has no fundamental role in the dyeing mechanism as such and some disperse dyes without ester groups do not need a weakly acidic dye bath. Fastness properties on Polyester - If extremely high light fastness is needed (automotive fabrics) a nonionic UV inhibitor may be added to the dye bath and applied to the fiber along with the dye. These compounds often benzotriazoles work much like sunscreen, screening out and dissipating UV radiation to prevent sunburn. - Wet fastness tests are frequently conducted after the goods have been reduction cleared and heatset at 180c for 30 seconds. They are assessed in terms of the staining on multifibre or adjacent nylon piece goods. Rating of 4+ out of 5 are readily achieved on regular denier fibers. - Fastness to crocking or rubbing as well as dry cleaning suffers if dye migrates to the fiber surface or surface layer Polyester Fiber Physical Factors Drawing : Polyester Fiber Physical Factors Drawing : refractive index vs dye adsorption Increase in orientation and crystallinity close packing dyeability 15min dye adsorption equilibrium dye adsorption Refractive index Refractive index 39 40

9 Polyester Fiber Physical Factors Drawing vs diffusion coefficient Polyester Fiber Physical Factors eat setting Diffusion coefficient Draw ratio - Fabric set at 120 o showed 53% exhaustion - fell to minimum values of about 34% exhaustion at heat setting temperatures between o - rising rapidly to 75% at 230 o Glass Transition Temperature, T g - The temperature at which the moveable segments of the polymer chains become quite suddenly susceptible to deformation and displacement - The polymer properties change from glassy to rubbery and in the increasing thermal agitation of the polymer segments. - Polyester fibers are intrinsically slow dyeing at the boil. Below they are for all practical purposes undyeable. - The temperature which polyester dyeing begins to occur more rapidly has been called the dyeing transition temperatures. Fiber Structure Modification The inclusion of alternative co-monomers into regular polyester as like as- S 3 5-sulphoisopthalic acid 4 8 1,4 butane diol - The possibility of making the fiber dyeable with cationic dyes, has the effect of lowering both the melting point of the fiber and also its glass transition temperature. - The effect can be attributed to the new monomer disrupting the molecular orderliness of the structure making it easier to leave the glassy state

10 Fiber Structure Modification ationic dyeable PET / alkali-soluble PET Poly(ethyleneterephthalate-co-5-sodiosulfoisophthalate). 2 2 x PET m S 3 a 2 2 y Sulfonated Isophthalate (SIP) n Fiber Fineness A useful preliminary relationship between the percentages of dye on weight of goods () needed to achieve a particular depth of shade on polyester fibers of two different fineness (D, denier) is given below: 2 D1 D 1 The microfiber will dye approximately three times as first which could lead to the need for procedural changes in dyeing to counter possible unevenness due to inadequate circulation. 2 ationic dyeable Alkali-soluble Water-dispersible / Water-soluble If the same apparent depth is dyed on both fibers the wet fastness after heat setting of the shade on the microfiber will be significantly reduced. This is because of both the increased surface area and the greater percentage dye on the fiber. SIP, wt % ommercial Products Disperse Dyes Reactive Dyes and Their Application Powders Grains Pastes Solid forms constitute two thirds of the total dye solid. Dusting can be controlled by incorporation of small amounts of oil. Grains are free from dust Pouring characteristics are very easy. ne third of disperse dye sold on paste form. With stored pastes it is important to prevent sedimentation

Disperse dyes. Disperse dyes. Disperse dyeing process. Disperse dyeing mechanism. Dye solid. Dye micelles. Dye fiber. Disperse Dyeing Mechanism.

Disperse dyes. Disperse dyes. Disperse dyeing process. Disperse dyeing mechanism. Dye solid. Dye micelles. Dye fiber. Disperse Dyeing Mechanism. Disperse dyes Disperse dyes - Disperse dyes are nonionic, have very limited solubility in water at room temperature - They have substantivity for one or more hydrophobic fibers e.g. Polyesters, cellulose