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ColorationTechnology

Society of Dyers and Colourists

Dyeing and fastness properties ofbenzodifuranones, naphthodifuranones andnaphthofuranonepyrrolidonesChun Yoona,* and G Hallasb

aDept of Applied Chemistry, Sejong University, Seoul, KoreaEmail: chunyndm@yahoo.co.kr

bDept of Colour Chemistry, University of Leeds, Leeds LS2 9JT, UK

Dyeings were carried out on polyester with benzodifuranones, naphthodifuranones and naphtho-furanonepyrrolidones (which had been synthesised previously) to study dyeing properties.Symmetrically and asymmetrically substituted naphthodifuranones showed poor dyeing properties interms of dyeing and fastness. Asymmetrically substituted red benzodifuranones showed excellentdyeing properties and fastness. Asymmetrically substituted blue benzodifuranones showed gooddyeing properties; however, the colour hue was dull and the light fastness was inferior. Thenaphthofuranonepyrrolidones showed similar dyeing and fastness to those of symmetrically substitutednaphthodifuranones, but the colour hue was duller.

IntroductionBenzodifuranones were first introduced by researchers atICI in the early 1980s [1]. Asymmetrically substituted redbenzodifuranones showed much better fastness propertiesand brighter colours than conventional disperse dyes in thered colour shade range [2]. In the present study, dyeing andfastness properties of the more bathochromic dyes wereexamined. These bathochromic dyes were synthesised byreplacing the central nucleus with a naphthalene moietyand by replacing alkoxy groups with alkylamino groups.Such modified structures offer the possibility of extensioninto the blue colour shade range. The synthesis andphysical properties of benzodifuranones 1, naphthodi-furanones 2 and naphthofuranonepyrrolidones 3 have beendescribed previously [3,4]. All the dyes used in this study

R1

O

O

OR2

O

R1

O

OR2

O

O

R1

O

NR2

O

O

H

1 2

3

R1 = H, CH3, CH3O, Cl R2 = Alkoxy, Alkylamino

(see Tables 1–3 for a full list) were synthesised and purifiedfor dyeing tests, even though some dyes are availablecommercially.

A number of synthetic methods were used to preparethe various dyes that were subsequently used in thispresent study. Symmetrically disubstituted red benzo-difuranones (BDFs) were synthesised directly by reactionof hydroquinone with an appropriate mandelic acid [1,3].Asymmetric monosubstituted red BDFs, which have goodbuild-up and less bathochromism on polyester, were pre-pared by the reaction of halfway intermediates withappropriate mandelic acids [3,5,6]. Asymmetrically disub-stituted red BDFs were synthesised in a similar mannerand these dyes showed much improved build-up onpolyester with more bathochromism. Blue BDFs were

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obtained by replacing alkoxy groups with electron richalkylamino groups [3,7]. Symmetrically disubstituted bluenaphthodifuranones (NDFs) were synthesised directly bythe reaction of 1,5-dihydroxynaphthalene with an appro-priate mandelic acid [8,9]. Asymmetric monosubstitutedand disubstituted blue NDFs were obtained by the reactionof halfway intermediates with appropriate mandelic acids[4]. Symmetrically disubstituted blue naphthofuranonepyr-rolidones (NFPs) could be obtained from 1-amino-5-hydroxynaphthalene and appropriate mandelic acids [4].

To examine the dyeing behaviour of these dyes and tocorrelate this with structure, dyeing tests were carried outusing a high temperature dyeing method followed by analkali-clearing process in which the dyed fabric was heatedin alkaline solution to destroy unfixed dye on the surface.Unfixed dye can cause problems by lowering wet, sublim-ation and rub fastness.

30 s with undyed polyester as adjacent fabrics, and thesublimation fastness of each dyed sample was assessed bystaining of the adjacent fabric. Each 0.2% owf dyed samplewas illuminated by a mercury lamp (500 W) for 240 h andthe light fastness assessed using SDC Blue Wool standardsamples.

ExperimentalPreparation of dye dispersionsDye (100 mg) in 100 g of an aqueous solution of dispersingagents [250 mg of Ultrazine NA (Boregarrd Ind.) and 50mg of Reax 85A (Westvaco Corp.)], with 300 g of glassbeads, was ground in a plastic jar (diameter, 9 cm; height,10 cm) for 2–3 h. A gear shaped agitator (diameter, 7 cm)was employed for grinding, and the rotation speed was ca.1500 rpm. The glass beads were filtered off using cottoncloth and the filtered dye paste was diluted to 200 g withdistilled water. The mean particle size was measured by aCoulter Multisizer and was found to be < 1 µm for BDFsand ca. 3 µm for NDFs and NFPs.

Application to polyesterEach dye was applied at concentrations of 0.1, 0.2, 0.4 and1.0% owf to 5 g of knitted conventional polyester fabric[167f32 (167 dtex fibre comprising 32 filaments), 5.2dtexpf] using the high temperature dyeing method usinga Mathis dyeing machine (Werner Mathis AG). The dyebathtemperature was raised to 140 °C (at 2 °C/min) and thistemperature was then maintained for 1 h. After dyeing, thedyed samples were rinsed well in cold tap water and alkali-cleared by heating in sodium hydroxide solution (2 g/l ofsodium hydroxide) at 80 °C for 30 min.

The colour strength, K/S, of the resulting dyeings weremeasured on a Macbeth spectrophotometer. The K/S valueswere automatically converted to fk values by the machine.

Measurement of colour propertiesThe hue angles, chroma (C*) and hue (h), of typical dyeswere measured to compare their brightness in the bluecolour region by using a BYK-color guide 11 machine (D65/10°). Three different points were measured on eachspecimen and the results averaged. This test wasperformed to assess the brightness, and hence the potentialfor commercialisation of blue BDF dyes.

Measurement of fastness propertiesThe ISO 105-C06 wash fastness test was carried out for the0.2% owf dyed samples with multifibre, steel balls and ECEreference detergent. The sublimation fastness test (ISO 105-P01) of each 0.1% owf dyeing was carried out at 200 °C for

Results and DiscussionDye build-up properties on polyesterTables 1–3 show the dyeing results for the polyestersamples dyed with BDFs, NDFs and NFPs, respectively.The results are given as the fk values for each dye; fk is avisually weighted function of K/S, which indicates thestrength of each dyeing [10]. Many of the dyes exhibitedpoor dyeing properties, except for the BDFs. Both the redand blue BDFs showed excellent dyeing properties in termsof build-up and fastness, however for the blue BDFs thecolour was dull and the light fastness was inferior. NDFsshowed very poor build-up on polyester and poor lightfastness, but the colour hue was bright. The NFPs showedsimilar dyeing and fastness properties to those of NDFs,but the colour was duller.

The BDF dyes, synthesised from hydroquinone, havemuch better build-up on polyester than the other dyes. Forthis class of dye, it is the symmetrically substituted redBDFs that have poorest levels of build-up due to their highcrystallinity [8]. It is considered that the dyes synthesisedfrom 1,5-dihydroxynaphthalene and 1-amino-5-hydroxy-naphthalene also exhibit poor build-up due to low solubilityand high crystallinity. These dyes were too insoluble invarious solvents so that recrystallisation and columnchromatography could not be carried out for purification[1,2].

It was observed that the asymmetric red BDFs have muchimproved build-up properties compared with their sym-metric analogues. For example, symmetrically disubstitutedpurple BDF (1a) shows an fk value of 94.15 at 1.0% owf,whereas the asymmetric monosubstituted red BDF (1b)shows fk values of 242.5 at the same dyeing depth. This poorlevel of dye uptake can be attributed to high crystallinity[2]. The asymmetrically disubstituted purple BDF (1e)shows much better build up and a very similar colour whencompared with the symmetrically disubstituted purple BDF(1a). The comparison of build-up on polyester between theasymmetric and the symmetric BDFs is represented inFigure 1 for the dyes 1a and 1b. From this figure it is evidentthat the build-up of BDFs is improved dramatically by theintroduction of asymmetric substitution.

The introduction of chlorine into the BDF structure hasa negative effect on the dye build-up, regardless of whetherred or blue BDFs are applied. This is evident for dyes 1dand 1m which have poorer build-up than 1b and 1h, i.e.their respective analogues without chlorine in the R1

position (see also Figure 2). However, introducing methylor methoxy groups into the BDF structure does not affectbuild-up property adversely.

Figure 3 explains clearly that asymmetric monosub-stituted blue BDFs exhibit generally better build-up onpolyester fibre than asymmetric monosubstituted red BDFs.Among the blue BDFs, dye 1h, which has a propylaminogroup, shows the greatest fk value of 365.5.

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Table 1 fk values for benzodifuranones 1a–1n

Dyeing depth (% owf)

Dye R1 R2 0.1% 0.2% 0.4% 1.0% Colour Structurea

1a O(CH2)2CH3 O(CH2)2CH3 57.67 66.57 92.96 94.15 Purple sdb

1b H O(CH2)2CH3 59.25 113.0 176.7 242.5 Red amb

1c CH3 O(CH2)2CH3 77.37 183.3 205.8 295.2 Red adb

1d Cl O(CH2)2CH3 52.52 84.40 99.87 110.1 Red adb

1e OCH3 O(CH2)2CH3 58.42 103.2 166.6 237.4 Purple adb

1f H NHCH3 66.52 121.6 200.0 249.3 Blue amb

1g H NHCH2CH3 74.18 148.6 205.0 256.0 Blue amb

1h H NH(CH2)2CH3 58.26 115.5 198.2 365.5 Blue amb

1i H NHCH(CH3)2 69.94 128.9 203.9 296.4 Blue amb

1j H NH(CH2)3CH3 72.45 142.0 223.0 298.4 Blue amb

1k H N(CH2CH2CH3)2 35.86 62.85 97.01 207.3 Green blue amb

1l CH3 NH(CH2)2CH3 37.09 88.36 130.7 187.3 Blue adb

1m Cl NH(CH2)2CH3 36.80 61.03 124.5 153.4 Blue adb

1n CH3O NH(CH2)2CH3 65.49 84.85 131.0 199.4 Blue adb

a sdb = symmetrically disubstituted benzodifuranone; adb = asymmetrically disubstituted benzodifuranone; amb =asymmetric monosubstituted benzodifuranone

Table 2 fk values for naphthodifuranones 2a–2n

Dyeing depth (% owf)

Dye R1 R2 0.1% 0.2% 0.4% 1.0% Colour Structurea

2a H H 13.08 16.28 19.79 24.13 Violet sdn2b O(CH2)2CH3 O(CH2)2CH3 13.91 18.49 25.81 37.08 Green blue sdn2c O(CH2)3CH3 O(CH2)3CH3 16.28 21.18 25.27 29.92 Green blue sdn2d H OCH3 38.93 55.41 64.34 71.06 Blue amn2e H OCH2CH3 27.24 40.32 60.24 78.55 Blue amn2f H O(CH2)2CH3 45.45 52.51 73.65 84.51 Blue amn2g H OCH(CH3)2 41.18 56.25 59.26 65.45 Blue amn2h H O(CH2)3CH3 33.13 49.27 56.34 61.92 Blue amn2i H O(CH2)2OC2H5 31.81 48.89 78.51 99.32 Blue amn2j CH3 O(CH2)2CH3 27.67 34.04 63.24 65.65 Blue adn2k Cl O(CH2)2CH3 20.12 31.23 40.99 51.65 Blue adn2l CH3O O(CH2)2CH3 43.50 56.36 60.80 66.90 Green blue adn2m CH3 OCH2CH3 28.04 46.56 51.22 55.42 Blue adn2n CH3 O(CH2)2OC2H5 37.93 54.67 70.80 84.09 Blue adn

a sdn = symmetrically disubstituted naphthodifuranone; amn = asymmetric monosubstituted naphthodifuranone;adn = asymmetrically disubstituted naphthodifuranone

Table 3 fk values for naphthofuranonepyrrolidones 3a–3e

Dyeing depth (% owf)

Dye R1 R2 0.1% 0.2% 0.4% 1.0% Colour Structurea

3a OCH3 OCH3 47.51 49.41 63.60 78.59 Green blue sdf3b OCH2CH3 OCH2CH3 24.78 25.80 35.10 47.17 Green blue sdf3c O(CH2)2CH3 O(CH2)2CH3 24.88 32.38 37.49 50.03 Green blue sdf3d OCH(CH3)2 OCH(CH3)2 20.44 24.92 31.67 39.83 Green blue sdf3e O(CH2)3CH3 O(CH2)3CH3 19.97 27.12 34.55 41.58 Green blue sdf

a sdf = symmetrically disubstituted naphthofuranonepyrrolidone

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they generally have poorer build-up than asymmetricmonosubstituted NDFs (e.g. 2f).

An interesting result was obtained with dye 2i, with a2-ethoxyethoxy group, which has a better build-up at highdyeing depth than the corresponding dye 2h with butoxycompound. Presumably, this can be attributed to increasedaffinity between dye and fibre due to the ether linkage.Introduction of methyl, chlorine and methoxy into the NDFsystem gives lower build-up on polyester compared withdyes without these groups. In other words, asymmetricallydisubstituted NDFs have generally poorer build-up thanasymmetric monosubstituted NDFs.

NFPs are structurally asymmetric compared with NDFsso that they have generally better build-up on polyester(Table 3). The typical NFP dye 3c has an fk value of 50.03at 1.0% dyeing depth, whereas the corresponding sym-metric NDF 2b has an fk value of only 37.08 at the samedyeing depth.

Comparison of brightness in blue colour regionThe brightness (hue angles) of six typical dyes weremeasured and the data are listed in Table 4. From theresults it is clear that NDFs, especially monosubstitutedNDFs, showed generally better brightness than the blueBDFs and NFPs. In contrast, red BDFs are comparable withanthraquinone dyes in terms of brightness [11]. The hueangle of symmetrically disubstituted NDF 2b showedslightly better brightness when compared with those ofNFP dyes. These measurement data in Table 4 are con-sistent with visual inspection.

Wash, light and sublimation fastnessWash fastness ratings for the polyester dyeings (at 0.2%dyeing depth) are given in Tables 5–7. Some dyes, es-pecially NDFs and NFPs, have quite low build-up in highdyeing depth, low dyeing depth samples (0.2% owf) werethus used to obtain reasonable results. In general, the washfastness of disperse dyes on polyester tends to increasewith molecular size. Additionally, BDFs show structurallysuperior wash fastness when compared with ordinary azoor anthraquinone dyes with similar molecular mass. BDFsgenerally have low diffusion coefficients so that they are

owf, %

fk v

alue

0.4 0.6 0.8 1.00.2

100

200

300

1b

1a

Figure 1 Comparison of build-up between asymmetric (1a) andsymmetric (1b) benzodifuranones

owf, %

fk v

alue

0.2 0.4 0.6 0.8 1.0

120

240

360 1h

1m

Figure 2 Comparison of build-up between benzodifuranoneswith (1m) and without (1h) chlorine

owf, %

fk v

alue

0.2

120

240

360

0.4 0.6 0.8 1.0

1h

1b

Figure 3 Comparison of build-up between typical blue (1h) andred (1b) benzodifuranone

Dyes synthesised from 1,5-dihydroxynaphthalene exhibitmuch poorer build-up on polyester compared with dyessynthesised from hydroquinone (Table 2). However, asym-metric NDFs have better build-up than symmetric NDFs,due to the structural asymmetry. This is evident in Figure4 for asymmetrically disubstituted NDF 2l which showsbetter build-up than symmetrically disubstituted NDF 2b.Although asymmetrically disubstituted NDFs exhibit betterbuild-up compared with symmetrically disubstituted NDFs,

owf, %

fk v

alue

0.2

15

30

45

60

75

90

0.4 0.6 0.8 1.0

2f

2l

2b

Figure 4 Comparison of build-up between symmetricdisubstituted (2b) and asymmetric mono- (2f) and di-substituted(2l) naphthodifuranones

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Table 4 Colour properties, in terms of chroma (C*) and hue (h), of dyeings at variouscolour depths for typical dyes

Dyeing depth (% owf)

0.1 0.2 0.4 1.0

Dye Structure C* h (°) C* h (°) C* h (°) C* h (°)

1h amb 22 241 20 243 16 248 10 2551m adb 22 237 21 243 19 248 18 251

2b sdn 29 236 29 237 30 238 28 2402f amn 38 273 38 276 38 279 37 283

3b sdf 29 247 28 247 28 249 27 2533c sdf 27 248 27 249 26 253 27 264

Table 5 Fastness properties of benzodifuranones 1a–1n

Wash fastness

Staining

Light SublimationDye Polyester Cotton Nylon Change fastness fastness

1a 4–5 5 4 5 6–7 51b 5 5 5 5 6 4–51c 4–5 5 4 5 6 4–51d 4–5 5 4–5 5 6–7 51e 4–5 5 4–5 5 6–7 51f 5 5 4–5 5 3–4 4–51g 5 5 5 5 3–4 4–51h 5 5 5 5 3 4–51i 5 5 4–5 5 3–4 51j 5 5 4–5 5 3–4 51k 5 5 5 5 3–4 51l 5 5 5 5 3 4–51m 5 5 5 5 3 51n 4–5 5 4–5 5 3–4 5

Table 6 Fastness properties of napthodifuranones 2a–2n

Wash fastness

Staining

Light Sublimation

Dye Polyester Cotton Nylon Change fastness fastness

2a 5 5 5 5 1–2 4–52b 5 5 5 5 2–3 52c 4–5 5 4–5 5 2–3 52d 5 5 5 5 3 52e 5 4–5 5 5 3 52f 5 5 5 5 2–3 52g 5 4–5 5 5 3 52h 5 5 5 5 3 52i 5 5 5 5 3 52j 5 5 5 5 2–3 52k 5 5 5 5 2–3 52l 5 4–5 5 5 2–3 52m 5 4–5 5 5 3 52n 5 4–5 5 5 3 5

Table 7 Fastness properties of napthofuranonepyrrolidones 3a–3e

Wash fastness

Staining

Light SublimationDye Polyester Cotton Nylon Change fastness fastness

3a 5 4–5 5 5 2–3 4–53b 5 5 4–5 5 2–3 53c 5 5 5 5 2–3 53d 5 5 4–5 5 2 53e 5 5 4–5 5 2 5

slow to be fixed in fibres [10]. However, once fixed, dyemolecules tend to remain in the fibre. Consequently, BDFsare very useful for dyeing microfibres which need excellentwash fastness due to the increased surface area.

As shown in Tables 5–7, almost all the BDF, NDF andNFP dyes exhibit good wash fastness. The staining whichoccurred on the adjacent multifibre fabric was consistentlyobserved on nylon, presumably because of the combinationof the substantivity of the dyes for nylon and accessibilityof nylon at the test temperature (60 °C). Exceptionally, inthe case of asymmetric NDFs, the staining occurred mainlyon cotton rather than nylon. Many red BDFs show stainingon polyester and nylon, whereas blue BDFs show stainingmainly on nylon. Blue BDFs have generally better washfastness than red BDFs. NFPs show staining mainly onnylon.

The light fastness of the various dyes is much morevaried (ranging from 2–7). Red BDFs show excellent lightfastness properties with values ranging from 6–7. BlueBDFs have much poorer light fastness than related redBDFs, but they have slightly better light fastness (3–4) thanasymmetric NDFs (2–3). Asymmetric NDFs show some-what better light fastness than symmetrically disubstitutedNDFs and NFPs. The introduction of chlorine into thependant ring does not improve the light fastness of the blueBDF 1m and NDF 2k dyes.

Sublimation fastness of dyed samples was assessed bythe staining of the adjacent fabric. In general, disperse dyes

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with high relative molecular mass and high polarity showthe best sublimation fastness. The results of this studyshow that the sublimation fastness properties for all of thedyes examined were very good. Some of the red BDFs andthe blue BDFs exhibited slightly poorer sublimationfastness due to their relatively low molecular mass. Dyescontaining the naphthalene nucleus generally showedexcellent sublimation fastness.

ConclusionsRed BDFs which have an asymmetric structure showedexcellent dyeing properties (build-up, brightness, wash,sublimation and light fastness) and these compounds areworth considering as commercial dyes. Blue BDFs showedsimilar build-up and dyeing properties, however these dyesresult in very dull colours, such as dull navy blue or green,which along with their poor light fastness makes themdifficult to exploit commercially.

Dyes synthesised from 1,5-dihydroxynaphthaleneshowed bright colours; asymmetric dyes have a brightneutral blue colour and symmetric NDF have a brightturquoise colour. These dyes exhibited much poorer build-up on polyester than the red BDFs regardless of theirasymmetric or symmetric structure. However, asymmetricNDF have better build-up than symmetric NDF. Addition-ally, these dyes exhibited the worst light fastness. Washfastness and sublimation fastness for the various NDF were

excellent due to their high molecular masses andinsolubility.

NFPs exhibited very similar dyeing properties to thoseof the symmetrical NDF. The low solubility and highcrystallinity of NDF dyes might make these dyes suitableas pigments. Thus, this possibility should be studiedfurther. The colour of NFPs are a duller turquoise blue thanthose of the symmetrically disubstituted NDF, but the dyeshave better build-up on polyester due to asymmetry.

References 1. C W Greenhalgh, J C Carey and D F Newton, Dyes Pigm., 1

(1980) 103. 2. C W Greenhalgh, J C Carey, N Hall and D F Newton, J.S.D.C.,

110 (1994) 178. 3. G Hallas and C Yoon, Dyes Pigm., 48 (2) (2001) 107. 4. G Hallas and C Yoon, Dyes Pigm., 48 (2) (2001) 121. 5. ICI, EP 0033583 (1981). 6. Sumitomo, EP 0371223 (1990). 7. ICI, EP 0502278 (1992). 8. J L Carey, C A Shand, R H Thomson and C W Greenhalgh, J.

Chem. Soc., Perkin Trans. 1 (1984) 1957. 9. P A Smith, Synthesis and examination of benzodifuranone

analogues, PhD Thesis, University of Leeds (1995).10. J R Aspland, Textile Dyeing and Coloration (North Carolina:

AATCC, 1997) 395.11. O Annen, R Egli, R Hasler, B Henzi, H Jakcob and P Matzinger,

Rev. Prog. Color., 17 (1987) 72.

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