The effect of polyhydroxyurethane on dyeing of cellulosic fabrics with direct and reactive dyes
Stefan Oprea
P.Poni Institute of Macromolecular Chemistry,Aleea Grigore Ghica Voda˘41A,Iasi 700487,Romania
Email:reactive drop是什么意思
Received:18May2007;Accepted:20July2007
Dye yields and fastness properties are reported for direct and reactive dyes using a modified dyeing solution with polyhydroxyurethane.Excellent dye yields and colour fastness properties were obtained without the use of electrolytes,multiple rinsing orfixation agents,which are normally employed in cotton dyeing.From the results,it was found that polyhydroxyurethane media exhibit better dyeability and fastness than the normal aqueous media.Dye adsorption in polyhydroxyurethane media was much higher than in other aqueous systems.The dyed samples showed good hot pressing and washing colour fastness properties within the color change range.The excellent solubility of these dyes in the polyhydroxyurethane aqueous solution makes them ideal for use in exhaustion dyeing.
Introduction
In the textile industry,fibrous materials are subjected to coloration using various commercial dyes.The structure of reactive dyes is attributed to chemical bonding between suitable groups in the dye molecule and hydroxy groups in the cellulosefibre.The dyes are usually dissolved or dispersed in an exhaustion medium and then diffused into the polymer molecules[1,2].All the dyeing systems require a huge amount of electrolyte and alkali to exhaust andfix the dye,respectively.The salt remains at the end of the dyeing process and is very difficult and expensive to remove from the effluent.
N-Methylol reagents,such as dimethyloldihydroxy-ethyleneurea(DMDHEU),have been used in the textile industry as durable pressfinishing agents for a long time [3–7].The drawbacks of DMDHEU application are the well-known formaldehyde problems and the drop in tensile and tear strength of cotton fabrics[6].In recent years,there have been extensive efforts tofind non-formaldehyde alternatives because of increasing concern with health and environmental risks associated with formaldehyde.
Polyhydroxyurethanes exhibit useful characteristics such as high water absorption and thermal stability. Polyhydroxyurethanes are superior to commercial polyurethanes produced by the polyaddition of diisocyanates with diols.Polyhydroxyurethanes can be synthesised by the polyaddition of bis-(five-membered cyclic carbonates)with diamines[8–10].In the present study,two types of dyes were applied to a cotton sample in polyhydroxyurethane aqueous solution and the reluctant dyeing and fastness pro
perties were compared. It is possible to eliminate the detrimental auxiliary agents by the application of polymers such as polyhydroxyurethane in textilefinishing processes.By employing a polyhydroxyurethane method,salt and alkali can be completely eliminated from the dyeing process and,in comparison with standard dyeing processes,the time taken for the dyeing process to be completed and the volume of water required can both be reduced. Experimental
Materials
For this study,woven cotton fabrics were used.Fabrics used were of100%cotton and were scoured before being dyed.Polyhydroxyurethane(PHU)was synthesised in our laboratory by the reaction of ethylene carbonate,ethylene diamine and acrylic acid(Scheme1)[11].
PHU is a water-soluble polymer with many reactive groups(hydroxy groups)which can be used to crosslink thefibre and the dye.The polymer has a molecular weight in the region of30000–50000g/mol.
The two reactive dyes used in this study were Cibacron Yellow F-3R and Cibacron Blue F-R,commercial samples that were not purified prior to use.The two direct dyes used were Direct Yellow1and grey Direct Grey Resistant L,commercial samples that were not purified prior to use, and which were kindly supplied by Sintofarm(Romania). All other reagents were of a general-purpose grad
e.
Dye application
Using the above ingredients,the fabric was scoured in a laboratory jigger at a boiling temperature for2h.The
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1
doi:10.1111/j.1478-4408.2007.00104.x
fabric was then given a hot wash and a cold wash.
The fabric was scoured with NaOH (3%w/w)Na 2CO 3
(2%w/w)and nonionic wetting agent (0.5%w/w).The
fabric samples were dyed in a BFA-12Mathis Labomat
laboratory dyeing machine (Switzerland),at a
concentration of 1%owf dye and a 20:1liquor ratio.The
dyebath contained 40g of NaCl and 10g of Na 2CO 3per
litre of dyebath.All fabrics were wetted in cold water
before dyeing was carried out.The dyed samples were
dried at room temperature (25 C).In our case,the PHU
concentration of 1%owf without the use of electrolytes.
The temperature course of the dyeing process is shown in
Figure 1.
Ultraviolet absorption and fluorescence measurements
Ultraviolet-visible (UV-vis)absorption and fluorescence
spectra of freshly prepared solutions were recorded using
A Perkin-Elmer MpF-66fluorescence spectrophotometer
(USA).
Colour measurement
After drying,the reflectance spectra of samples were
recorded using a MatchRite colour spectrophotometer
(USA)connected to a personal computer.From the
reflectance values (R )at a specified wavelength (k )of
dyeing,the colour strength (K /S )of the sample was
calculated using the Kubelka–Munk equation [12].
Colour fastness
The cotton samples were dyed in order to test the colour
fastness,which was determined according to ISO
standards.The specific tests used were colour fastness to
washing (ISO 105-C06/C2S),colour fastness to
perspiration (ISO 105-E04),colour fastness to rubbing
and colour (ISO 105-X12)and fastness to hot pressing
(ISO 105-X11).Staining and change in colour were
assessed using grey scales.Results and Discussion Colorimetric analysis of dyed samples The K /S values calculated from the colorimetric data for the dyes applied using both the standard (electrolyte)method and also the PHU method are shown in Table 1.It was observed that the K /S values secured using the
PHU method were higher for all dyes used in comparison with the standard dyeing.Nevertheless,this is advantageous,as less dye would need to be applied using the PHU system to achieve a specific K /S value,hence reducing both the cost and the concentration of electrolytes and dye in the effluent.It is proposed that this result was achieved because less dye is hydrolysed and more of the dye applied fixes to the cotton.Visual inspection of the samples showed only slight variations in shade between dye type when comparing colour differences between standard and PHU dyeings.This was also true with th
e colour strength (K/S )values.Direct Yellow dyed fabric showed a 15%increase in K/S values,and Direct Grey dyed fabric gained 12%in K/S value.UV absorption No significant differences for direct or reactive dyes emerge when comparing their properties in an aqueous solution and a PHU aqueous solution.Figures 2and 3illustrate the absorption spectra for both the dyes recorded in pure water and those in a polyurethane aqueous solution.The shape of the spectrum for dye–PHU is nearly identical to that observed in the dye–water system.It is important that,in order to be used on cotton fabric,an essential requirement of this agent is to consider its absorption range,otherwise the treated samples could unintentionally be stained with colour.Fluorescence studies These dye–PHU complexes were further analysed by using a fluorescence spectrophotometer (Figures 4–7).The impact of dye aggregation is evident in the fluorescence spectra and it is clear that the intensity is high for the non-aggregating dye.PHU in the dye solution suppresses the tendency to aggregate and leads to higher
fluorescence intensities.
Dyeing properties
The addition of electrolyte increases the rate of strike of
the dye;when cellulose is immersed in a solution of a reactive dye it absorbs dye from the solution until
equilibrium is attained,and at this stage most of the dye is taken up by the fibre.80
for dyeing with electrolites for dyeing with polyhydroxyurethane 70A B
T e m p ., °C    A 40g/l sodium chloride B 10g/l sodium carbonate 40104050
Time, min 1001100
0Figure 1Temperature course of the dyeing process
Table 1Colour strength of the direct dyes and reactive dyes on cotton fabrics in normal electrolytes and with 1%owf polyhydroxyurethane Dye Process K/S Direct Yellow
Electrolyte 8.6PHU 11.74Direct Grey Electrolyte
9.9PHU
14.1Reactive Yellow Electrolyte
9.2PHU
13.9Reactive Blue Electrolyte
6.8PHU 10.5Oprea Effect of polyhydroxyurethane on dyeing of cellulosic fabrics
The diffusion coefficient of the dye is therefore a
function of both dye and electrolyte concentration.It is
considered that the initial rapid rise is because of the response of dye to the lowering of the electrical potential barrier to diffusion as the concentration of electrolyte increases.
A
990
880
770
660
550
440
330
220
110
020012240260280300320340, nm
360380400420440460480500
λFigure 2UV spectra of (1)Direct Grey and (2)in the PHU solution
F l u o r e s c e n c e  i n t e n s i t y 500
400300200100
400
200600021Wavelength, nm Figure 4Fluorescence emission spectra of (1)reactive yellow
and (2)in the PHU solution F l u o r e s c e n c e  i n t e n s i t y 10008006004002000200100500
400300021Wavelength, nm Figure 6Fluorescence excitation spectra of (1)reactive yellow and (2)in the PHU solution
A 900
800
700
600
500400
300
200
100
020*********
500600
, nm λFigure 3UV spectra of (1)Direct Grey and (2)in the PHU solution
F l u o r e s c e n c e  i n t e n s i t y 10008006004002000200100500400300021Wavelength, nm Figure 7Fluorescence excitation spectra of (1)direct grey and
(2)in the PHU solution
F l u o r e s c e n c e  i n t e n s i t y
400
300200100
400200
600021Wavelength, nm
Figure 5Fluorescence emission spectra of (1)direct grey and (2)
in the PHU solution Oprea Effect of polyhydroxyurethane on dyeing of cellulosic fabrics
The PHU increases the probability of contact between the dye molecules and thefibre surface.Attachment is through both hydrogen bonds and van der Waals forces, as the intensity of the latter increases with the increase in molecular size.The hydrogen bonding capability is also aided by the square and molecular structure of the PHU polymers which enables them to lie along a cellulose chain in register with hydroxy groups.
Fastness properties
The colouristic and application properties of direct dyes with PHU were determined in order to compare them with those of a similar dye.The results of the fastness studies for the dye-PHU complex and for the normal solution are summarised in Table2.It is shown that the fastness to dry rubbing of standard depth dyeing of the direct dyes with PHU complex on cotton fabric was higher than that of comparable depth dyeing in normal solution.These results could be attributed to the excellent affinity of PHU to dyes because of its supramolecular characteristics.Table2also reveals that,while the alkaline perspiration fastness of the standard depth dyeing of Reactive Yellow with PHU on cotton fabric was identical to that of the dye in normal solution,the hot pressing of PHU was higher.In the case of rubbing fastness,the dry-rubbing and wet-rubbing fastness of the reactive dyes with PHU on cotton fabric was much better than that of normal solution.This may as a result of the strength of thefibre dye and PHU,a
nd the fact that there is no hydrolysed dyefixed in the fabric. According to the data obtained,the cotton fabrics are bestfinished by means of direct dyestuffs in the solution with a concentration of below1%owf PHU. Considering that the PHU used in the dyeing processes was applied in a relatively low concentration,it is suggested that it would have high exhaustion values; hence,its presence in the effluent would be expected to be in extremely low concentrations.It would be expected that,because of its high affinity for cellulose,the agent would not be removed during laundering.In addition,the agent is polymeric and as such poses a minimal environmental impact.
Although there is no definitive toxicological analysis at present for this agent,preliminary testing suggests that the agent is non-toxic.
From these results,we can conclude that dye complexed with PHU as the dyeing component is an excellent substitute for various auxiliary agents used in dyebath conditions.
Conclusions
It has been demonstrated that the dyeing of cotton with PHU enables the dyeing of uniform shades with high colour strength values good to very good fastness to the wash test.
The dyed cotton samples with PHU are characterised by a better uniformity in the dyeing and a good blended effect.The dyed textiles are characterised by good dry-rubbing and fastness properties(grades2–3to4–5).All dyed samples show a high level of hot-pressing fastness properties:from grade2to grades4–5for the dyes with PHU.
The application,colouristic and fastness properties on cotton of the PHU–dye complex were even better in comparison with those of dye alone,and this would indicate that PHU is an excellent substitute for various auxiliary agents of the dyebath.
References
1.J Koh,I S Kim,S S Kim,W S Shim,J P Kim and S Y Kwak,
J.Appl.Polym.Sci.,91(2004)3481.
2.J Koh,I S Kim,S S Kim,W S Shim and J P Kim,Fibers
Polym.,5(2004)44.
3.Y Lu and C Q Yang,Text.Res.J.,69(1999)685.
4.B J Morrell and B A Andrews,Text.Res.J.,62(1992)144.
5.H A Pertersen,Chemical Processing of Fibers and Fabrics:
Functional Finishes.Part A,Eds M Lewin and S B Sello (New York:Marcel Dekker,1983)47.
6.C M Welch,Rev.Prog.Color.,22(199232.
7.W L Xu,Text.Res.J.,70(2000)8.
8.N Kihara and T J Endo,Polym.Sci.,A:Polym.Chem.,31
(1993)2765.
9.H Tomita,H Hidaka,F Sanda and T Endo,J.Polym.Sci.,A:
Polym.Chem.,39(2001)860.
10.G Rokicki and J Czajkowska,J.Appl.Polym.Sci.,41(1990)
647.
11.S Oprea,C Ciobanu and O I Nastase,RO111465(1996).
12.R McDonald,J.S.D.C.,96(1980)486.
Table2Fastness data for the dyes used in this study
Dye Process Hot pressing Dry rubbing Wet rubbing Water wash40°C Perspiration(alkaline) Direct Yellow Electrolyte2234–14–1
PHU54–544–24–2
Direct Grey Electrolyte3334–14–1
PHU5544–24–2
Reactive Yellow Electrolyte2444–14–1
PHU4–54–554–24–2
Reactive Blue Electrolyte3444–14–1
PHU5554–24–2
Oprea Effect of polyhydroxyurethane on dyeing of cellulosic fabrics

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