Method for coloration and treatment of substrates
09945072 ยท 2018-04-17
Assignee
Inventors
Cpc classification
D06B21/02
TEXTILES; PAPER
Y02P70/62
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
D06P1/00
TEXTILES; PAPER
D06M23/08
TEXTILES; PAPER
International classification
D06B21/02
TEXTILES; PAPER
D06B19/00
TEXTILES; PAPER
D06M23/08
TEXTILES; PAPER
D06P1/00
TEXTILES; PAPER
Abstract
The invention provides a method for the application of a treatment agent to a substrate, the method comprising the treatment of the pre-wetted substrate in an aqueous system comprising the solid particulate treatment agent in a closed container, the treatment being carried out at a ratio of liquor to substrate which does not exceed 2:1. Typically, the method is applied to the dyeing of textile fibres at liquor ratios of 1:1 and is carried out in the absence of additives conventionally included for the sole purpose of promoting dye uptake by controlling electrical interactions or otherwise enhancing interactions between the substrate and the treatment agent. The invention also provides a method for the removal of surplus treatment agents following application of said treatment agents to a substrate, said method comprising not more than three wash-off treatments of said substrate with water following said application. Said wash off process most particularly comprises a two-stage process comprising performing, in order, the steps of: a first wash-off of the treated substrate with water in a closed container at a ratio of water to substrate which does not exceed 5:1; and a second wash-off of the treated substrate with water in a closed container at a ratio of water to substrate which does not exceed 10:1.
Claims
1. A method for the application of a treatment agent to a substrate, said method comprising the treatment of the substrate in an aqueous system comprising the solid particulate treatment agent in a closed container, said treatment being carried out at a ratio of liquor to substrate which does not exceed 2:1, wherein the substrate is treated with an aqueous liquor comprising said solid particulate treatment agent, wherein said treatment agent is present in said aqueous liquor in partially or wholly dissolved form or partially or wholly suspended or dispersed form, wherein said substrate comprises a natural or synthetic textile substrate, or a substrate comprising a blend of natural, man-made, synthetic textile fibres or a combination thereof, wherein said natural textile substrate comprises wool, cotton, silk or a combination thereof and said synthetic textile substrate optionally comprises polyester, polyamide, polyalkene, polyacrylonitrile, cellulose di- or tri-acetate or a combination thereof, wherein said solid particulate treatment agent optionally comprises a powder or pellets, wherein said solid particulate treatment agent is optionally added to the treatment system at a level in the region of 1-5 % w/w of the substrate being treated; wherein said solid particulate treatment agent comprises at least one dye; wherein said method is carried out in the absence of added dye uptake-promoting additives, wherein said added dye-uptake promoting additives are optionally selected from electrolytes, the halide or sulphate salts of alkali metals, the salts of mono-, di-, or tri-carboxylic acids or betaines, acids, buffering agents, acid donor agents, or dispersing agents.
2. A method as claimed in claim 1 wherein said at least one dye is selected from acid dyes, azoic colorants, basic dyes, direct dyes, reactive dyes, disperse dyes, vat dyes and sulphur dyes.
3. A method as claimed in claim 1 wherein said solid particulate treatment agent comprises a textile finishing chemical selected from water-repelling agents, anti-creasing agents, anti-bacterial agents and fluorescent brightening agents.
4. A method as claimed in claim 1 wherein said solid particulate treatment agent comprises at least one bleaching agent.
5. A method as claimed in claim 1 wherein said aqueous system comprises at least one additional assisting agent selected from an alkaline material, an acid, an oxidising agent, a reducing agent and a surfactant.
6. A method as claimed in claim 1 wherein said treatment comprises the wetting out of the substrate using an aqueous liquor comprising said solid particulate treatment agent, said wetting out being carried out at a ratio of liquor to substrate which does not exceed 2:1.
7. A method as claimed in claim 1 wherein said treatment comprises spraying either one or both sides of said substrate with an aqueous liquor comprising said solid particulate treatment agent so as to provide a ratio of liquor to substrate which does not exceed 2:1.
8. A method as claimed in claim 1 wherein said treatment comprises the wetting out of the substrate with water and the subsequent treatment of the wetted out substrate with the solid particulate treatment agent.
9. A method as claimed in claim 1 which is carried out at a temperature in the range of from 20 to 140 C. or at a liquor to substrate ratio of 1:1 or wherein said closed container is a sealed dyepot or other sealable dyeing or fabric treatment apparatus, or wherein the aqueous system containing the substrate is agitated during the performance of the method, or wherein said treatment is carried out for a duration of between 10 to 45 minutes.
10. A method as claimed in claim 1 wherein the treated substrate is subsequently washed-off or rinsed or both washed off and rinsed.
11. A method as claimed in claim 10 wherein said method comprises not more than three wash-off treatments of said substrate with water following said application.
12. A method as claimed in claim 11, said method comprising a three-stage process comprising performing, in order, the steps of: (a) A first wash-off of the treated substrate with water in a closed container at a ratio of water to substrate which does not exceed 2:1; (b) A second wash-off of the treated substrate with water in a closed container at a ratio of water to substrate which does not exceed 2:1; and (c) A final wash-off of the treated substrate with water in a closed container at a ratio of water to substrate which does not exceed 20:1.
13. A method as claimed in claim 12 wherein the first and second wash-off steps are carried out at ambient temperature (15-25 C.), whilst the final wash-off step is performed at a temperature of 40-80 C. or wherein the duration of each wash-off step is in the region of from 10-15 minutes.
14. A method as claimed in claim 12 wherein the first and second wash-off steps are carried out at ambient temperature (15-25 C.) for a duration in the region of from 10-15 minutes and the final wash-off step is performed at ambient temperature (15-25 C.) for a duration of 15-45 minutes.
15. A method as claimed in claim 12 wherein the substrate is rinsed with tap water at ambient temperature after each wash-off step.
16. A method as claimed in claim 11, said method comprising a two-stage process comprising performing, in order, the steps of: (a) A first wash-off of the treated substrate with water in a closed container at a ratio of water to substrate which does not exceed 5:1; and (b) A second wash-off of the treated substrate with water in a closed container at a ratio of water to substrate which does not exceed 10:1.
17. A method as claimed in claim 16 wherein the second wash-off step is performed at ambient temperature of 15-25 C. or wherein the duration of the first wash-off step is in the region of 15 minutes or wherein the second wash-off step is performed for a duration of around 3 minutes.
18. A method as claimed in claim 16 wherein rinsing of the substrate with tap water at ambient temperature after each wash-off step is not carried out.
19. A method as claimed in claim 11 wherein one or more of said wash-off processes is performed in the absence of added auxiliary treatment agents.
20. A method for the application of a treatment agent to a substrate, said method comprising the treatment of the substrate in an aqueous system comprising the solid particulate treatment agent in a closed container, said treatment being carried out at a ratio of liquor to substrate which does not exceed 2:1, wherein the substrate is treated with an aqueous liquor comprising said solid particulate treatment agent, wherein said treatment agent is present in said aqueous liquor in partially or wholly dissolved form or partially or wholly suspended or dispersed form, wherein said substrate comprises a natural or synthetic textile substrate, or a substrate comprising a blend of natural, man-made, synthetic textile fibres or a combination thereof, wherein said natural textile substrate comprises wool, cotton, silk or a combination thereof and said synthetic textile substrate optionally comprises polyester, polyamide, polyalkene, polyacrylonitrile, cellulose di- or tri-acetate or a combination thereof, wherein said solid particulate treatment agent optionally comprises a powder or pellets, wherein said solid particulate treatment agent is optionally added to the treatment system at a level in the region of 1-5 % w/w of the substrate being treated, wherein the treated substrate is subsequently washed-off or rinsed or both washed off and rinsed, said method comprising not more than three wash-off treatments of said substrate with water following said application and wherein one or more of said wash-off processes is performed in the absence of added auxiliary treatment agents.
21. A method for the application of a treatment agent to a substrate, said method comprising the treatment of the substrate in an aqueous system comprising the solid particulate treatment agent in a closed container, said treatment being carried out at a ratio of liquor to substrate which does not exceed 2:1, wherein the substrate is treated with an aqueous liquor comprising said solid particulate treatment agent, wherein said treatment agent is present in said aqueous liquor in partially or wholly dissolved form or partially or wholly suspended or dispersed form, wherein said substrate comprises a natural or synthetic textile substrate, or a substrate comprising a blend of natural, man-made, synthetic textile fibres or a combination thereof, wherein said natural textile substrate comprises wool, cotton, silk or a combination thereof and said synthetic textile substrate optionally comprises polyester, polyamide, polyalkene, polyacrylonitrile, cellulose di- or tri-acetate or a combination thereof, wherein said solid particulate treatment agent optionally comprises a powder or pellets, wherein said solid particulate treatment agent is optionally added to the treatment system at a level in the region of 1-5 % w/w of the substrate being treated, wherein said solid particulate treatment agent comprises at least one bleaching agent.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) Embodiments of the invention are further described hereinafter with reference to the accompanying drawings, in which:
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DESCRIPTION OF THE INVENTION
(21) Specific embodiments of the first aspect of the present invention involve the wetting out of textile materials with water so as to achieve a substrate to liquor ratio of 1:1. The wetted textile material is then placed in a container together with a dye (in powder, pelletised or other dry form, such as grains, granules, and the like) and, if appropriate, at least one additional assisting agentfor example an alkaline material in the case of reactive dyes and cellulosic materials. The container should be of suitable ullage so as to enable an adequate level of movement of the damp textile material and dyes (and optional other agents), and also to facilitate the development of a water vapour environment within the sealed container. The sealed container is then agitated in a suitable machine at the appropriate temperature until dyeing is achieved, which typically would take around 30 minutes.
(22) In other embodiments of the first aspect of the present invention, non wetted-out textile materials may be treated by either spraying or immersing the substrate with an aqueous solution which comprises the at least one treatment agent dye and, if appropriate, at least one additional assisting agent. The amount of the aqueous solution applied to the textile substrate is typically such as to achieve a substrate to liquor ratio of about 1:1. The treated textile material is typically placed in a container which is then sealed. The container is of appropriate ullage to enable an adequate level of movement of the damp, treated substrate and the development of a water vapour environment within the sealed container. The sealed container is then agitated in a suitable machine at the appropriate temperature until dyeing is achieved, which typically would take around 30 minutes.
(23) Thus, it is seen that the disclosed process is extremely simple and efficient. As previously observed, it may be applied to the application of finishes to textile materials, as well as for the dyeing of these materials. Hence, the invention facilitates the application of dyes and finishes, by an exhaust method, to all types of textile fibres in a wide range of physical forms at a liquor ratio of 1:1 (or, optionally, higher) without the requirement for inclusion of significant quantities of additional agents as dyeing assistants. Indeed, pH adjustment of the dyebath is not always necessary for any dye types other than those wherein a chemical reaction of the dye occursi.e. reactive dyes and vat dyes when applied to cellulosic fibresand, even in such applications, the amounts of additional agents employed are significantly lower than with the methods of the prior art. Thus, for example, in the case of reactive dyes on cellulosic fibres, wherein the addition of an amount of alkali is necessary, this amount is approximately 30% of that which is used in conventional aqueous exhaust dyeing.
(24) On completion of treatments according to the method of the first aspect of the invention, the treated substrate may be washed-off/rinsed using conventional methods well known in the art. However, in view of the fact that water usage levels according to the method of the invention are so low, it is found that, unlike conventionally treated materials, those treated by the disclosed method do not require hydro-extraction (e.g. by spinning, centrifuging or the like) prior to further processing.
(25) In view of the fact that the levels of additional agents and additives employed in the method of the first aspect of the invention are low as a consequence of the reduced level or complete absence of certain additional electrolytes, acids, buffering agents, acid donor agents and dispersing agents, it is found thatunlike conventionally treated materialsthose materials treated by the disclosed method, particularly in the context of dye application to textile materials, do not require stringent or prolonged wash-off processes to remove surplus dyes and such added assisting agents which are present subsequent to dyeing. Thus, in certain embodiments of the invention, the treated substrate may be washed-off using the method according to the second aspect of the present invention, said method comprising not more than three wash-off treatments of said substrate with water following said application.
(26) In certain embodiments of the method according to the second aspect of the invention, said method comprises a three-stage process comprising performing, in order, the steps of: (a) A first wash-off of the treated substrate with water in a closed container at a ratio of water to substrate which does not exceed 2:1; (b) A second wash-off of the treated substrate with water in a closed container at a ratio of water to substrate which does not exceed 2:1; and (c) A final wash-off of the treated substrate with water in a closed container at a ratio of water to substrate which does not exceed 20:1.
(27) Particularly favourable results are achieved with said embodiments when the steps (a) and (b) are carried out at a L:R of 2:1 and the L:R in step (c) is 5-10:1.
(28) The first and second wash-off steps are typically carried out at ambient temperature (15-25 C.), whilst the final wash-off step is performed at a temperature of 40-80 C., most particularly at around 70 C. The duration of each wash-off step is typically in the region of from 10-15 minutes, although the final wash-off step may alternatively also be performed at ambient temperature (15-25 C.) for a longer duration of 15-45 minutes. The substrate is generally rinsed with tap water at ambient temperature after each wash-off step, before being finally allowed to dry.
(29) In alternative embodiments of the method according to the second aspect of the invention, said method comprises a two-stage process comprising performing, in order, the steps of: (a) A first wash-off of the treated substrate with water in a closed container at a ratio of water to substrate which does not exceed 5:1; and (b) A second wash-off of the treated substrate with water in a closed container at a ratio of water to substrate which does not exceed 10:1.
(30) In said embodiments, the first wash-off step is typically carried out at temperatures between the ambient (15-25 C.) and 98 C., whilst the second wash-off step is performed at ambient temperature of 15-25 C. The duration of the first wash-off step is typically in the region of 15 minutes, whilst the second wash-off step is generally performed for a shorter duration of around 3 minutes. Rinsing of the substrate with tap water at ambient temperature after each wash-off step is generally not necessary, and the substrate can simply be allowed to dry after the second wash-off step.
(31) In particularly favoured embodiments of the second aspect of the invention, one or more of the wash-off processes may be performed in the absence of added auxiliary treatment agents, such as surfactants.
(32) This method is particularly suited to the washing-off of substrates wherein the treatments agents are dyes, i.e. in the washing-off of dyed substrates, especially when the dyes have been applied using the method according to the first aspect of the invention.
(33) Whilst the solid particulate treatment agent used in the method of the invention may be in any suitable form, it is frequently found that advantageous results are associated with the use of pelletised materials. Most particularly, the inventors have employed pelletisation to provide pellets of alkali and dye as well as alkali/dye admixture. Such an approach has been shown to facilitate the controlled release of both dye and alkali during dyeing procedures.
(34) In alternative embodiments of the invention wherein non wetted-out textile materials are treated by either spraying or immersing the substrate with an aqueous solution which comprises at least one solid particulate treatment agent and, if appropriate, at least one additional assisting agent, the textile substrate is treated with an aqueous liquor comprising said solid particulate treatment agent and said optional at least one assisting agent, wherein said treatment agent and said assisting agent may be present in said aqueous liquor in partially or wholly dissolved or suspended form.
(35) As previously suggested, the present inventors attribute the success of the presently claimed method to the provision of saturated water vapour and an appropriate saturated water vapour pressure within the container, together with an appropriate level of physical interaction between dye and wetted substratetypically textilematerial, which facilitates efficient dyeing and finishing according to the method of the invention, even at the very low (1:1) liquor ratios and relatively short treatment times which are employed.
(36) Mechanistically, in the case of the application of solid particulate materials (e.g. treatment agents such as dyes, and additional assisting agents such as dyebath assistants), it is important that the textile material should be moistened (i.e. wetted-out) in order for success to be achieved; in this regard, the addition of surfactant to the water used for wetting-out promotes wetting-out and aids dye/finisher-fibre interchange, thereby promoting uniform application of the treatment agent, which is particularly important in the case of dyeing procedures. However, it should be stressed that the method of the invention may still be successfully performed in the absence of surfactant.
(37) As previously noted, in performing the method of the invention, the wetted substrate may be added to the container together with the solid particulate treatment agent and any additional solid particulate treatment agent and/or additional assisting agent; alternatively, these agents may be included in the wetting out process, so that the substrate is wetted-out (at a typical liquor ratio of 1:1) using water which contains dye and/or finisher and optionally other agents, or may be sprayed onto the substrate.
(38) The success of the claimed method in achieving excellent results in dyeing and finishing processes without the requirement for the use of high temperatures can be attributed to the fact that, even at comparatively low temperatures (i.e. 50-65 C., compared to conventionally used temperatures of around 98 C.), sufficient water vapour and water vapour pressure are generated within the sealed container, thereby facilitating the dissolution of the dye and/or finisher and its uniform absorption by the substrate. Specifically, in the case of the application of reactive dyes to textile substrates, it is observed that the use of lower levels of water and lower temperatures results in a lower level of reactive dye hydrolysis when compared to conventional exhaust dyeing.
(39) It is believed that the success of the method according to the second aspect of the invention is also attributable to the generation, even at low and comparatively low temperatures (i.e. room temperature and temperatures of around 70 C., rather than boiling point) of sufficient water vapour and water vapour pressure within the sealed container to facilitate the dissolution of surplus dye on the substrate in the wash-off water.
(40) The claimed invention will now be further illustrated, though without in any way limiting the scope of the disclosure, by reference to the following examples.
EXAMPLES
(41) The following examples of the method of the first aspect of the invention relate particularly to the application of reactive dyes to cotton, although the method of the invention is equally applicable to other substrate treatments, and especially to all dye-fibre systems, and further examples are provided of the application of metallised and non-metallised acid dyes on wool, nylon and silk, direct dyes on cotton and disperse dyes on polyester.
(42) Standard pelletisation procedures were used to obtain suitable pellets of alkali and dye, as well as alkali/dye admixture. This facilitated the controlled release of both dye and alkali during dyeing.
(43) Details and parameters of a dyeing process according to the first aspect of the invention are presented below, together with the equivalent parameters for a conventional process for dyeing cotton and other cellulosic fibres with reactive dyes, carried out according to the known techniques of the prior art:
(44) TABLE-US-00001 Parameter Conventional process Method of the Invention Liquor ratio 12:1 current best norm; 5:1 predicted goal ~1:1 1 tonne fabric = 12 tonnes water 1 tonne fabric = 1 tonne water Electrolyte 50-100 gL.sup.1 NaCl 0 gL.sup.1 NaCl 1 tonne fabric @ 50 gL.sup.1 electrolyte 1 tonne fabric = 0 kg NaCl @ 12:1 L:R = 600 kg of electrolyte Dye fixation 50-70% 90+% Alkali 15 gL.sup.1 Na.sub.2CO.sub.3 15 gL.sup.1 Na.sub.2CO.sub.3 1 tonne fabric, 15 gL.sup.1 Na.sub.2CO.sub.3 1 tonne fabric, 15 gL.sup.1 Na.sub.2CO.sub.3 @ 12:1 L:R = 180 kg of alkali @ 1:1 L:R = 15 kg of alkali Temperature 60-98 C. 65 C. Duration 90-120 minutes 30 minutes Wastewater large volume low volume (12 tonnes per tonne fabric) (1 tonne per tonne fabric) high NaCl content (50-100 gL.sup.1 NaCl) zero NaCl content (0 gL.sup.1 NaCl) high dye content reduced dye content Energy Using steam tables.sup.5: 1 tonne cotton dyed at 12:1 L:R 1 tonne cotton dyed at 1:1 L:R consumes ~1100 kWh energy consumes ~180 kWh energy
(45) Details and parameters of a wash-off process according to the second aspect of the invention are also presented, together with the equivalent parameters for a conventional process for the wash-off of cotton dyed with reactive dyes, carried out according to the known techniques of the prior art:
(46) TABLE-US-00002 Parameter Conventional process Method of the Invention Liquor ratio 8/20:1 best norm 2:1 3-4 stages with overflow rinsing, if required 3 stages, no overflow rinsing 1 tonne fabric = 24-120 tonnes water 1 tonne fabric = 11 tonnes water Electrolyte High electrolyte content No electrolyte in dyed fibre 1 tonne fabric @ 50 gL.sup.1 electrolyte 1 tonne fabric = 0 kg NaCl @ 10:1 L:R = 500 kg of electrolyte Dye fixation Low dye fixation (50-70%) Higher dye fixation (90+%) High dye level in wash liquor Lower dye level in wash liquor Alkali 15 gL.sup.1 Na.sub.2CO.sub.3 15 gL.sup.1 Na.sub.2CO.sub.3 High L:R, high alkali in dyed fibre Low L:R, low alkali in dyed fibre 1 tonne fabric, 15 gL.sup.1 Na.sub.2CO.sub.3 1 tonne fabric, 15 gL.sup.1 Na.sub.2CO.sub.3 @ 10:1 L:R = 150 kg of alkali @ 1:1 L:R = 15 kg of alkali Wash-off 1 tonne fabric using 1-3 gL.sup.1 No wash-off agent Agent 10:1 L:R = 10-30 kg wash-off agent in 0 kg wash-off agent in effluent effluent Temperature 95-98 C. typically for wash-off stage 40-80 C. typically Duration 90-110 minutes 65 minutes Energy Using steam tables.sup.5: 1 tonne cotton dyed at 10:1 L:R 1 tonne cotton dyed at 1:1 L:R consumes ~2200 kWh energy; consumes ~420 kWh energy; Wastewater large volume low volume (24-120 tonnes per tonne fabric) (11 tonnes per tonne fabric) high NaCl content (50-100 gL.sup.1 NaCl) zero NaCl content (0 gL.sup.1 NaCl)
Example 1
(47) This example relates to the application of direct dyes to cotton using dissolved dye.
(48) Scoured and bleached woven cotton fabric (180 gm.sup.2) was immersed in tap water for 5 seconds after which the fabric was mangled so as to provide 70% pick-up. In so doing, the water absorbed by the fabric resulted in a water:fabric liquor ratio (L:R) used in wetting-out of 1:0.7.
(49) An amount of the direct dyes C.I. Direct Blue 71, C.I. Direct Yellow 50 or C.I. Direct Red 81 required to achieve a 2% on mass of fibre (omf) depth of shade was dissolved in an appropriate amount of tap water so as to provide a L:R used in dyeing of 1:1.3. The amount of water required was calculated using Equation 1 below; for this example, the amount of water used to dissolve the direct dye, according to Equation 1 was, (1.13-1.07)=0.6mass of fabric employed.
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(51) The damp fabric was placed inside a container and the dye solution was added. The container was tightly sealed and heated at 65 C. for 30 minutes. At the end of dyeing, the sample was removed and dried.
(52) By way of the method of this example, direct dyeing of cotton was achieved using a L:R of 1:1.3 in the absence of added electrolyte.
(53) The colour strength (f(k) value) of the dyed fabrics obtained by way of this example were calculated from the reflectance values at the appropriate .sub.max for each dyeing measured using a Datacolor Spectroflash 600 reflectance spectrophotometer from 400 nm to 700 nm under illuminant D.sub.65, using a 10 standard observer with UV component included and specular component excluded. Samples were folded so as to realise two thicknesses and the average of four measurements was taken for each sample. The f(k) values obtained for the 2% omf dyeings were:
(54) C.I. Direct Blue 71: 251.8;
(55) C.I. Direct Yellow 50: 212.2;
(56) C.I. Direct Red 81: 106.5.
(57) The colour strength was also measured, using the method described above, of 2% omf dyeings of C.I. Direct Blue 71, C.I. Direct Yellow 50 and C.I. Direct Red 81 obtained on identical cotton fabric but using a conventional dyeing procedure. Thus, scoured and bleached woven cotton fabric (180 g m.sup.2) was placed in an aqueous solution comprising 2% omf dye and 20 gL.sup.1 NaCl, employing a 20:1 L:R. The ensuing dyebath was heated to 98 C. at a rate of 2 C. per minute and dyeing was continued at this temperature for 45 minutes. After this time, the dyebath was cooled at a rate of 3 C. per minute until a temperature of 40 C. was reached. The dyeing was removed and dried.
(58) The f(k) values obtained for these conventional 2% omf dyeings were:
(59) C.I. Direct Blue 71: 302.6;
(60) C.I. Direct Yellow 50: 178.5;
(61) C.I. Direct Red 81: 105.1.
(62) These findings show that the 2% omf dyeings obtained using a L:R of 1:1.3 at 65 C. for 30 minutes were comparable, in terms of colour strength, to those obtained using the conventional dyeing method carried out at 98 C. for 45 minutes in the presence of 20 gL.sup.1 electrolyte and using a L:R of 20:1.
Example 2
(63) This example relates to the application of disperse dyes to polyester using a spraying technique.
(64) Scoured woven polyester fabric (130 gm.sup.2) was immersed in tap water for 5 seconds after which the fabric was mangled so as to provide 80% pick-up. In so doing, the water absorbed by the fabric resulted in a water:fabric liquor ratio (L:R) used in wetting-out of 1:0.8.
(65) An amount of the disperse dyes Dianix Blue ACE (DyStar), C.I. Disperse Yellow 114 or C.I. Disperse Red 60 required to achieve a 2% omf depth of shade was dispersed in an appropriate amount of tap water so as to provide a L:R used in dyeing of 1:1.4. The amount of water required was calculated using Equation 1 above, which, in this example, was 0.6mass of fabric employed.
(66) The dye dispersion was sprayed at a pressure of 3 bar onto one side of the damp polyester fabric which was placed inside an appropriate container. The sealed container was heated to 130 C. at 2 C. per minute and dyeing was continued at this temperature for 10 minutes, after which time the container was cooled at a rate of 3 C. per minute until a temperature of 50 C. was reached. The dyed fabric was removed from the container and dried.
(67) The colour strength (f(k) value) of the dyed fabrics obtained by way of this example were calculated from the reflectance values at the appropriate .sub.max for each dyeing as described in Example 1. The f(k) values obtained for these 2% omf dyeings were:
(68) Dianix Blue ACE: 238.9;
(69) C.I. Disperse Yellow 114: 246.5;
(70) C.I. Disperse Red 60: 358.7.
(71) The colour strength was also measured, using the method described in Example 1, of 2% omf dyeings of Dianix Blue ACE, C.I. Disperse Yellow 114 and C.I. Disperse Red 60 obtained on identical polyester fabric but using a conventional dyeing procedure. Thus, scoured and bleached woven polyester fabric (130 gm.sup.2) was placed in an aqueous dispersion comprising 2% omf dye, 1 gL.sup.1 Levegal DLP (proprietary anionic levelling agent) and 1 gL.sup.1 Ludigol AR (anti-reducing agent) at pH 4.5 (Mcllvaine buffer), employing a 20:1 L:R. The ensuing dyebath was heated to 140 C. at a rate of 2 C. per minute and dyeing was continued at this temperature for 30 minutes, after which time the dyebath was cooled at a rate of 3 C. per minute until a temperature of 40 C. was reached. The dyeing was removed and dried.
(72) The f(k) values obtained for these conventional 2% omf dyeings were:
(73) Dianix Blue ACE: 245.1;
(74) C.I. Disperse Yellow 114: 252.8;
(75) C.I. Disperse Red 60: 379.9.
(76) These results reveal that the 2% omf dyeings obtained using a L:R of 1:1.4 at 130 C. for 10 minutes were comparable, in terms of colour strength, to those obtained using the conventional dyeing method carried out at 140 C. for 30 minutes in the presence of two proprietary auxiliary agents, at pH 4.5 and using a L:R of 20:1.
(77) The dyeing process was also carried out in the absence of dispersing agents and anti-reducing agents, and it was possible to achieve dyeing of polyester in the absence of these agents using a L:R of 1:1.4 at 130 C.
Example 3
(78) This example relates to the application of reactive dyes to cotton using solid dye.
(79) A 10 gL.sup.1 aqueous solution of an anionic surfactant such as dibutyl maleate was prepared. Scoured and bleached woven cotton fabric (180 gm.sup.2) was immersed in the aqueous surfactant solution for 5 seconds after which the fabric was mangled so as to provide 130% pick-up.
(80) The damp fabric was placed inside a container and an amount of the reactive dyes C.I. Reactive Black 5, C.I. Reactive Blue 19, Remazol Yellow R gran, or C.I. Reactive Red 198 required to achieve a 2% omf depth of shade was added. The container was then tightly sealed and heated at 65 C. for 10 minutes, after which time an appropriate amount of alkali was added so as to achieve a concentration of 5 gL.sup.1. The sealed container was heated at 65 C. for a further 20 minutes, after which the fabric was removed, rinsed with water and dried.
(81) By way of this example, reactive dyeing of cotton was achieved using a L:R 1:3 in the absence of added electrolyte at 65 C. for 30 minutes.
(82) Other surfactant types can be used including non-ionic, cationic and amphoteric, as well as appropriate blends thereof.
(83) The colour strength (f(k) value) of the dyed fabrics obtained by way of this example were calculated from the reflectance values at the appropriate .sub.max for each dyeing as described in Example 1. The f(k) values obtained for these 2% omf dyeings were:
(84) C.I. Reactive Black 5: 239.5;
(85) C.I. Reactive Blue 19: 101.5;
(86) Remazol Yellow R gran: 111.4;
(87) C.I. Reactive Red 198: 82.2.
(88) The colour strength was also measured, using the method described in Example 2, of 2% omf dyeings of C.I. Reactive Black 5, C.I. Reactive Blue 19, Remazol Yellow R gran and or C.I. Reactive Red 198 obtained on identical cotton fabric but using a conventional dyeing procedure. Thus, scoured and bleached woven cotton fabric (180 g m.sup.2) was placed in an aqueous solution comprising 2% omf dye and 50 gL.sup.1 NaCl employing a 20:1 L:R. The ensuing dyebath was heated to 60 C. at a rate of 2 C. per minute and dyeing continued at this temperature for 60 minutes, after which time 15 gL.sup.1 Na.sub.2CO.sub.3 was added and dyeing continued at 60 C. for a further 60 minutes. The dyebath was then cooled at a rate of 3 C. per minute until a temperature of 40 C. was reached. The dyeing was removed and dried.
(89) The f(k) values obtained for these conventional 2% omf dyeings were:
(90) C.I. Reactive Black 5: 221.5;
(91) C.I. Reactive Blue 19: 113.3;
(92) Remazol Yellow R gran: 98.5;
(93) C.I. Reactive Red 198: 63.5.
(94) These results show that the 2% omf dyeings obtained using a L:R of 1:3 at 65 C. for 30 minutes in the absence of added electrolyte were comparable, in terms of colour strength, to those obtained using the conventional dyeing method carried out at 60 C. for 120 minutes in the presence of 50 gL.sup.1 electrolyte and using a L:R of 20:1.
Example 4
(95) This example relates to the application of non-metallised acid dyes to nylon using a spraying technique.
(96) Scoured and bleached knitted nylon 6,6 fabric (166 gm.sup.2) was immersed in water for 5 seconds after which the fabric was mangled so as to achieve 68% pick-up. In so doing, the water absorbed by the fabric resulted in a water:fabric liquor ratio (L:R) used in wetting-out of 1:0.7.
(97) An amount of the non-metallised acid dyes C.I. Acid Blue 80, C.I. Acid Red 1, or C.I. Acid Yellow 17 required to achieve a 2% omf depth of shade, together with an amount of an anionic surfactant such as dibutyl maleate required to achieve a concentration of 2% omf, were dissolved in an appropriate amount of tap water so as to provide a L:R used in dyeing of 1:2.3. The amount of this water required was calculated using Equation 1 above, which, for this example, amounted to 1.6mass of fabric employed.
(98) An amount of acetic acid was added to the dye solution so as to achieve a pH of 3.0.
(99) The acidified dye solution was sprayed at a pressure of 3 bar onto one side of the damp nylon fabric which was placed inside an appropriate container. The sealed container was heated to 75 C. at 2 C. per minute, and dyeing was continued at this temperature for 40 minutes, after which time the container was cooled at a rate of 3 C. per minute until a temperature of 50 C. was reached. The dyed fabric was removed from the container and dried.
(100) The invention permits the use of a wide range of acidic pH values, from pH 2.0 to pH 7.0, preferably within the range pH 3.0 to pH 5.0; the desired pH can be achieved through the use of various acids and/or buffer systems.
(101) The colour strengths (f(k) values) of the dyed fabrics obtained by way of this example were calculated from the reflectance values at the appropriate .sub.max for each dyeing as described in Example 1. The f(k) values obtained for these 2% omf dyeings were:
(102) C.I. Acid Blue 80: 117.0;
(103) C.I. Acid Red 1: 115.5;
(104) C.I. Acid Yellow 17: 51.7.
(105) The colour strength was also measured, using the method described in Example 2, of 2% omf dyeings of C.I. Acid Blue 80, C.I. Acid Red 1 and C.I. Acid Yellow 17 obtained on identical nylon 6,6 fabric but using a conventional dyeing procedure. Thus, scoured and bleached nylon 6,6 fabric (166 gm.sup.2) was placed in an aqueous solution comprising 2% omf dye and 20 gL.sup.1 Na.sub.2SO.sub.4, at pH 4.5 (Mcllvaine buffer), employing a 20:1 L:R. The ensuing dyebath was heated to 98 C. at a rate of 2 C. per minute and dyeing continued at this temperature for 60 minutes, after which time the dyebath was cooled at a rate of 3 C. per minute until a temperature of 50 C. was reached. The dyeing was removed and dried.
(106) The f(k) values obtained for these conventional 2% omf dyeings were:
(107) C.I. Acid Blue 80: 109.5;
(108) C.I. Acid Red 1: 118.2;
(109) C.I. Acid Yellow 17: 51.9.
(110) These findings reveal that the 2% omf dyeings obtained using a L:R of 1:2.3 for 40 minutes at 75 C. were comparable, in terms of colour strength, to those obtained using the conventional dyeing method carried out at 90 C. for 60 minutes in the presence of sodium sulphate and using a L:R of 20:1.
Example 5
(111) This example relates to the application of pre-metallised acid dyes to silk using dissolved dye.
(112) The procedure described in Example 4 was repeated except that woven silk fabric (170 gm.sup.2) was immersed in water for 5 seconds after which the fabric was mangled so as to provide 80% pick-up. In so doing, the water absorbed by the fabric resulted in a water:fabric liquor ratio (L:R) used in wetting-out of 1:0.7.
(113) An amount of the pre-metallised acid dyes Supra/an Blue GLW, Supra/an Red S-RL, Supra/an Yellow 4GL or Supra/an Black S-B required to achieve a 2% omf depth of shade, together with an amount of an anionic surfactant such as dibutyl maleate required to achieve a concentration of 2% omf, were dissolved in an appropriate amount of tap water so as to provide a L:R used in dyeing of 1:2.2. The amount of this water required was calculated using Equation 1 above which, for this example, amounted to 0.52mass of fabric employed.
(114) The damp fabric was placed inside a container and the dye solution was added. The container was tightly sealed and heated at 65 C. for 30 minutes after which time, the dyed sample was removed and dried.
(115) By way of this example, silk was dyed using pre-metallised acid dyes using a L:R 1:2.2 in the absence of added acid, and after 30 minutes at low temperature.
Example 6
(116) This example relates to the application of reactive dyes to cotton using separate pellets of dye and additional assisting agent in a single stage procedure.
(117) The reactive dyes C.I. Reactive Black 5, C.I. Reactive Blue 19, Remazol Yellow R gran, or C.I. Reactive Red 198 were mixed with microcrystalline cellulose and polyethylene glycol in the mass % ratio 10:70:20, and the ensuing admixture was formed into a pressed pellet.
(118) Sodium carbonate was mixed with microcrystalline cellulose in the mass % ratio 20:80 and the resulting mixture was formed into a pressed pellet.
(119) Scoured and bleached woven cotton fabric (180 gm.sup.2) was immersed in water for 5 seconds, after which the fabric was mangled so as to provide 70% pick-up. In so doing, the water absorbed by the cellulosic material resulted in a water:fabric liquor ratio (L:R) used in wetting-out of 1:0.7.
(120) The damp fabric was placed inside a container and an amount of reactive dye pellet required to achieve a 2% omf depth of shade was added together with an appropriate amount of alkali pellet required to achieve a concentration of 5 gL.sup.1. The container was tightly sealed and heated at 65 C. for 30 minutes, after which time the dyed fabric was removed, rinsed with water and dried.
(121) By way of this example, reactive dyeing of cotton was achieved using a L:R 1:07 in the absence of added electrolyte, and using the combined, controlled release of dye and alkali, each from pellet form.
(122) In an alternative procedure, the reactive dye and alkali pellets may be added in a two-stage process wherein the dye is added and the sealed container is heated at 65 C. for 10 minutes, after which the alkali addition takes place and the sealed container is heated at 65 C. for a further 20 minutes, providing comparable results.
Example 7
(123) This example relates to the application of non-metallised acid dyes to wool using dissolved dye.
(124) Scoured and bleached woven wool fabric (240 gm.sup.2) was immersed in water for 5 seconds, after which time the fabric was mangled so as to achieve 56% pick-up. In so doing, the water absorbed by the fabric resulted in a water:fabric liquor ratio (L:R) used in wetting-out of 1:0.56.
(125) An amount of the non-metallised acid dyes C.I. Acid Blue 80, C.I. Acid Red 1, or C.I. Acid Yellow 17 required to achieve a 2% omf depth of shade, together with an amount of an anionic surfactant such as dibutyl maleate required to achieve a concentration of 2% omf, were dissolved in an appropriate amount of tap water so as to provide a L:R used in dyeing of 1:1.2. The amount of this water required was calculated using Equation 1 above, which, for this example, amounted to 0.64mass of fabric employed.
(126) The damp fabric was placed inside a container and the dye solution was added. The container was tightly sealed and heated at 65 C. for 30 minutes. At the end of dyeing, the sample was removed and dried.
(127) By way of this example, wool was dyed using non-metallised acid dyes employing a L:R of 1:1.2 after 30 minutes at low temperature.
(128) The colour strength (f(k) value) of the dyed fabrics obtained by way of this example were calculated from the reflectance values at the appropriate .sub.max for each dyeing as described in Example 1. The f(k) values obtained for these 2% omf dyeings were:
(129) C.I. Acid Blue 80: 245.1;
(130) C.I. Acid Red 1: 241.2;
(131) C.I. Acid Yellow 17: 119.6.
(132) The colour strength was also measured, using the method described in Example 2, of 2% omf dyeings of C.I. Acid Blue 80, C.I. Acid Red 1 and C.I. Acid Yellow 17 obtained on identical wool fabric, but using a conventional dyeing procedure. Thus, scoured and bleached wool fabric (240 gm.sup.2) was placed in an aqueous solution comprising 2% omf dye and 10 gL.sup.1 Na.sub.2SO.sub.4, at pH 4.0 (Mcllvaine buffer), employing a 20:1 L:R. The ensuing dyebath was heated to 95 C. at a rate of 2 C. per minute and dyeing continued at this temperature for 60 minutes, after which time the dyebath was cooled at a rate of 3 C. per minute until a temperature of 50 C. was reached. The dyeing was removed and dried.
(133) The f(k) values obtained for these conventional 2% omf dyeings were:
(134) C.I. Acid Blue 80: 247.5;
(135) C.I. Acid Red 1: 254.7;
(136) C.I. Acid Yellow 17: 123.4.
(137) These findings show that the 2% omf dyeings obtained using a L:R of 1:1.2 for 30 minutes at 65 C. with pH unadjusted were comparable, in terms of colour strength, to those obtained using the conventional dyeing method carried out at 95 C. for 60 minutes in the presence of sodium sulphate at pH 4.0 and using a L:R of 20:1.
(138) Thus, the present invention provides an ultra-low water application method which is applicable to the treatment of all textile fabrics with any dyes and/or finishing agents and provides results which are at least as good as, and typically better than, those achieved by means of conventional processes.
Example 8
(139) This example relates to the application of reactive dyes to cotton using different levels of alkali in the dyebath.
(140) Three dyes were used in the example, namely C.I. Reactive Black 5 (bis vinyl sulfone), C.I. Reactive Red 198 (aminochlorotriazine/masked vinyl sulfone) and Remazol Yellow R (vinyl sulfone).
(141) 2% omf dyeings of C.I. Reactive Black 5, employing a 1:1 L:R in the absence of electrolyte and using 5, 10, 15 and 20 gL.sup.1 Na.sub.2CO.sub.3 were carried out according to the method of the first aspect of the invention, as illustrated in
(142) Simultaneously, conventional 2% omf dyeings of C.I. Reactive Black 5 were carried out, as illustrated in
(143) For each of the dyeing procedures, at the end of dyeing, the sample was removed from the dyebath, squeezed to remove surplus dye liquor and subjected to the conventional prior art wash-off procedure.sup.6,7, which is illustrated in
(144) The results are shown in
(145)
(146) Turning to
(147) An interesting corollary of employing a low L:R in the reactive dyeing of cotton is the effect upon the amount of electrolyte used per mass of fabric. As is illustrated in Table 1, the volume of dye liquor used is determined by L:R; this means that, because alkali concentration is determined by the volume of the dye liquor (i.e. the amount of Na.sub.2CO.sub.3 used is measured in gL.sup.1), the amount of alkali employed per mass of fibre decreases markedly with decreasing L:R.
(148) TABLE-US-00003 TABLE 1 AMOUNT OF ALKALI USED PER KG OF FABRIC amount of amount of Na.sub.2CO.sub.3 alkali used per L:R liquor used/L conc./gL.sup.1 kg of fabric/g 20:1 20 15 300 5:1 5 15 75 1:1 1 15 15
(149) Thus, it can be seen that: 1 T fabric dyed using a 20:1 L:R uses 300 kg of alkali; 1 T fabric dyed using a 5:1 L:R uses 75 kg of alkali; 1 T fabric dyed using a 1:1 L:R uses 15 kg of alkali.
(150) Hence, a 1:1 L:R dyeing consumes 80% less alkali than dyeing at a 5:1 L:R and 95% less alkali than dyeing at a 20:1 L:R. It follows, therefore, that the lower the amount of alkali used, then the less wash-off/rinsing is required to remove the residual Na.sub.2CO.sub.3 at the conclusion of the dyeing process.
(151) The same dyeing processes were carried out using the other two dyes (C.I. Reactive Red 198 and Remazol Yellow R) and the comparative results for these dyes and C.I. Reactive Black 5 are set out in
(152) The dyeings were compared visually and in terms of the results obtained from the wash-off procedure.
(153)
(154)
(155) Thus, a comparison of
(156) On inspecting the dyeings, it was observed that for each of the three dyes studied, the method of the invention provides dyeings which are of at least comparative colour strength to those secured using the standard dyeing method. As noted above, there was little difference between the amounts of dye removed when the two dyeings were washed-off using the BASF recommended wash-off method, which implies that similar levels of dye adsorption and fixation were achieved using the two different methods.
Example 9
(157) This example illustrates the novel three-stage wash-off method according to the invention which uses a 2:1 L:R and compares the results obtained with those achieved using conventional wash-off methods.
(158) At the conclusion of each wash-off stage, samples of the residual wash-off liquor were collected and allowed to cool to ambient temperature before being compared.
(159) Cotton fabrics were dyed to 2% omf depth of shade with C.I. Reactive Black 5 in sealed, 300 cm.sup.3 capacity, stainless steel dyepots housed in a Roaches Pyrotec S dyeing machine, using the conventional dyeing procedure described in
(160) 1. Conventional Prior Art Method Using Cyclanon XC-W New
(161) The wash-off procedure shown in
(162) 2. Single Low L:R Wash Bath Method According to the Invention
(163) The dyed sample was wetted-out with sufficient tap water to constitute a 2:1 L:R and placed in a sealed container of suitable ullage to permit adequate fabric agitation which was heated to 65 C. and maintained at this temperature for 10 minutes, after which time the dyed sample was removed, rinsed in cold tap water and squeezed, according to the process shown in
(164) 3. Double Low L:R Wash Bath Method According to the Invention
(165) As illustrated in
(166) The washed-off dyeings were then subjected to the ISO 105:C06/C2S wash test method, and the results are illustrated in
(167) The results shown in
Example 10
(168) This example illustrates the novel two-stage wash-off method according to the invention which uses 5:1 and 10:1 L:R and compares the results obtained with those achieved using conventional wash-off methods.
(169) 2% omf dyeings (C.I. Reactive Black 5), employing a 1:1 L:R in the absence of electrolyte and using 15 gL.sup.1 Na.sub.2CO.sub.3, were carried out in a sealed 1000 cm.sup.3 plastic bag within a 1400 cm.sup.3 polypropylene sandwich box which was housed in a White Knight tumble dryer for both 30 and 45 minutes at 65 C. according to a low substantivity dyeing method of the first aspect of the invention, as illustrated in
(170) At the end of the low substantivity dyeing process, the dyed sample was removed from the dyebath, squeezed to remove surplus dye liquor and subjected to the BASF recommended wash-off procedure shown in
(171) Two-stage wash-off processes according to the second aspect of the invention were carried out wherein different temperatures (ambient, 50 C., 65 C., 80 C. and 98 C.) were used for each of the two wash-off baths, and the results obtained were compared to those secured using the conventional BASF wash-off process described above.
(172) Wash-Off Stage 1
(173) At the end of the dyeing process, the sample was removed from the dyebath and placed in heated (50 C., 80 C. and 98 C.) 300 cm.sup.3 capacity, stainless steel dyepots housed in a Roaches Pyrotec S dyeing machine for 15 minutes, according to the procedures illustrated in
(174) Wash-Off Stage 2
(175) At the end of each of the first wash-off treatments described above, each washed-off dyeing was removed from the dye tube/sandwich box, squeezed to remove surplus dye liquor and then placed in heated (50 C., 80 C. and 98 C.) 300 cm.sup.3 capacity, stainless steel dyepots housed in a Roaches Pyrotec S dyeing machine for 15 minutes, employing water at a L:R of 5:1, according to the schemes of
(176) In each case, the washed-off dyeings were squeezed and allowed to dry in the open air.
(177) The washed-off dyeings were subjected to the ISO 105-CO6/C2S wash fastness test.
(178) The example was specifically directed to providing a two bath wash-off process for reactive dyes which had been applied to cotton fabric using the dyeing method according to the invention which is illustrated in
(179) Conventional Dyeing and Conventional Wash-Off
(180) For comparison purposes, results obtained for 2% omf dyeings of C.I. Reactive Black 5 which had been carried out using the standard 20:1 L:R dyeing method of the prior art (typically 50 gL.sup.1 NaCl and 15 gL.sup.1 Na.sub.2CO.sub.3, 120 mins, 65 C.) in sealed, 300 cm.sup.3 capacity, stainless steel dyepots housed in a Roaches Pyrotec S dyeing machine are presented herewith. Table 2 shows the results obtained for a dyeing which had been squeezed, but not washed-off; the corresponding results obtained for a standard 20:1 L:R dyeing after it had been washed-off using the BASF recommended wash-off process illustrated in
(181) TABLE-US-00004 TABLE 2 COLORIMETRIC PARAMETERS BEFORE ISO 105-CO6/C2S WASH FASTNESS TEST duration of 1:1 L:R temp of wash-off dyeing method/ extended temperature/ mins dyeing/ C. C. L* a* b* C* h .sub.max 20:1 L:R standard dyeing BASF 20.6 2.1 13.8 14.0 261.0 600 (50 gl.sup.1 NaCl, 15 gl.sup.1 Na.sub.2CO.sub.3) 30 n/a BASF 19.5 1.3 12.9 13.0 263.8 30 + 15 65 19.2 1.0 12.7 12.8 265.3 30 + 15 65 room 20.2 1.7 12.9 13.0 262.4 30 + 15 50 50 20.0 1.3 13.6 13.7 264.4 30 + 15 65 65 19.7 1.1 13.4 13.4 265.1 30 + 15 80 80 20.1 1.2 13.5 13.6 264.5 30 + 15 98 98 21.6 2.1 14.1 14.3 261.4
(182) A comparison of the results displayed in Tables 2 and 3 reveals that the conventional, six-treatment bath BASF wash-off process removed surplus (unfixed and hydrolysed) dye, as observed in previous tests. Table 3 shows that the fastness of the 2% omf dyeing, which had been washed-off using the BASF process, to the ISO CO6/C2S wash test was excellent, with no staining of adjacent materials by vagrant dye and no change in shade of the dyeing.
(183) TABLE-US-00005 TABLE 3 COLORIMETRIC PARAMETERS AFTER ISO 105-CO6/C2S WASH FASTNESS TEST duration of 1:1 L:R temp of wash-off dyeing method/ extended temperature/ mins dyeing/ C. C. L* a* b* C* h .sub.max 20:1 L:R standard dyeing BASF 21.0 2.6 13.9 14.1 259.3 600 (50 gl.sup.1 NaCl, 15 gl.sup.1 Na.sub.2CO.sub.3) 30 n/a BASF 20.6 2.1 13.2 13.4 260.7 30 + 15 65 19.8 1.5 12.6 12.7 263.2 30 + 15 65 room 19.8 1.3 12.6 12.6 263.8 30 + 15 50 50 20.5 1.4 12.7 12.8 263.5 30 + 15 65 65 19.8 1.2 12.6 12.7 264.3 30 + 15 80 80 20.2 1.2 13.1 13.2 264.5 30 + 15 98 98 22.7 2.2 14.9 15.0 261.3
(184) TABLE-US-00006 TABLE 4 FASTNESS OF WASHED-OFF DYEINGS TO THE ISO 105-CO6/C2S WASH TEST duration of 1:1 L:R dyeing temp of wash-off change staining of adjacent method/ extended temperature/ of 2 mins dyeing/ C. C. shade wool acrylic polyester polyamide cotton acetate 20:1 L:R standard BASF 5 5 5 5 5 5 5 dyeing (50 gl.sup.1 NaCl, 15 gl.sup.1 Na.sub.2CO.sub.3 30 n/a BASF 5 5 5 5 5 4/5-5 5 30 + 15 65 5 5 5 5 5 5 5 30 + 15 65 room 5 5 5 5 5 4/5-5 5 30 + 15 50 50 4/5-5 4/5-5 5 5 5 4/5-5 5 30 + 15 65 65 4/5-5 4/5-5 5 5 5 4/5-5 5 30 + 15 80 80 5 5 5 5 5 4/5-5 5 30 + 15 98 98 5 5 5 5 5 5 5
Dyeing According to the Method of the Invention and Conventional Wash-Off
(185) Table 2 also shows the colorimetric data obtained for 2% omf dyeings of C.I. Reactive Black 5 which had been carried out using the 1:1 L:R dyeing process according to the invention (30 minutes, 65 C., as illustrated in
(186) In addition, Table 2 shows the colorimetric data obtained for 2% omf dyeings of C.I. Reactive Black 5 which had been produced using the 1:1 L:R dyeing process shown in
(187) As previously observed, an effective three-stage wash-off method has been devised in which a dyeing which had been produced using the 1:1 L:R method for 30 minutes, according to the invention, then squeezed, was subjected to treatment in two baths, each of 10-15 minute duration and employing a 2:1 L:R, followed by a third treatment in a bath at 70 C. for 10 minutes. However, cold water rinses were also performed at the end of each of the three wash-off baths, meaning that the wash-off process involved a total of six treatment baths with water.
(188) When conducting the present experiments, the purpose of extending the dyeing time at 65 C. from 30 minutes to 45 minutes was to attempt to replicate a 15 minute wash-off treatment. The results presented in Tables 2, 3 and 4 clearly show that extending the dyeing time at 65 C. from 30 to 45 minutes had beneficial effects on both colour yield and wash fastness. The finding (illustrated in
(189) Thus, it is seen that extending dyeing time from 30 to 45 minutes was effective in terms of both colour yield and fastness.
(190) Dyeing and Wash-Off According to the Method of the Invention
(191) As noted above, this example was specifically focused on an attempt to replace both the conventional BASF wash-off process and the existing low L:R wash-off process (each of which comprised a total of six treatment baths when the three additional rinse stages using water were taken into account), with a two bath process, wherein no rinse stages were required. Thus, in accordance with the procedure previously described, on conclusion of dyeing the dyed sample was removed, squeezed to remove surplus dye liquor, and then subjected to a total of two treatment baths, using the following steps: Bath 1: Sandwich Box/Dyeing Tube; Ambient Temperature, 50 C., 65 C., 80 C. or 98 C.; 15 minutes; water 5:1 L:R; Squeeze; Bath 2: Sandwich Box/Dyeing Tube; Cold; 3 minutes; water 10:1 L:R; Squeeze & dry.
(192) In this process, the low substantivity dyeing method according to the invention was employed (1:1 L:R; 30 minutes; 65 C., as shown in
(193) TABLE-US-00007 TABLE 5 WASH-OFF PROCESS ACCORDING TO THE INVENTION: DYEING AND WASH-OFF VARIANTS #1 Wash-off bath temp of #2 Wash-off bath Dyeing duration of 15 mins wash-off duration of 1:1 L:R extended dyeing extended temperature/ dyeing period/mins period/mins dyeing/ C. C. 30 15 65 room 30 15 50 50 30 15 65 65 30 15 80 80 30 15 98 98
(194) Thus, it is seen that the wash-off processes illustrated in
(195) The data presented in Table 2 show the colorimetric data obtained for 2% omf dyeings of C.I. Reactive Black 5 which were carried out using the 1:1 L:R dyeing process depicted in
(196) A comparison of the data in Tables 2 and 3 reveals that each of the five new two bath wash-off processes removed surplus (unfixed and hydrolysed) dye; clearly, none of the five new wash-off processes had a deleterious effect upon the hue or chroma of the dyeings either before or after wash-off. It is also evident that the colorimetric co-ordinates of the samples obtained using the five new processes were of very similar hue and chroma to those obtained for the standard 20:1 L:R dyeings as well as the two 1:1 L:R dyeings which had been washed-off using the BASF wash-off process.
(197) The fastness results obtained for the five 30+15 minute dyeings which had been washed-off using the two bath process are presented in Table 4, from which it is apparent that each of the five new wash-off processes imparted high levels of fastness, although the cotton adjacent was lightly stained by vagrant dye and the dyeing underwent a small shade change as a result of washing.
(198) It can therefore be concluded that the very high fastness recorded for the 98 C. wash-off method (Table 4) reflects the very low colour strength of the dyeing before wash-off (see
(199) It is evident, therefore, that in a particular embodiment, an aspect of the present invention provides a combined 1:1 L:R dyeing/two bath wash-off process which essentially comprises a 1:1 L:R dyeing process carried out at 65 C. for 45 minutes, after which the dyed material is squeezed to remove surplus dye; a first wash-off using water (5:1 L:R) at a temperature from ambient up to 80 C. for 15 minutes, after which the material is again squeezed to remove surplus liquor; and a second wash-off using water (10:1 L:R) for 3 minutes at room temperature, which is followed by a final squeeze and dry.
(200) Hence, in contrast to the wash-off processes of the prior art, the present inventors have provided a novel, two bath, low L:R wash-off process which does not employ any separate rinses with cold water after the wash-off baths. As previously disclosed, the process, which uses only water (i.e. no wash-off agent) is particularly effective when used with dyeings wherein reactive dyes which have been applied to cotton fabric using the novel 1:1 L:R dyeing method according to the invention (typically 30 minutes; 15 gL.sup.1 Na.sub.2CO.sub.3; no electrolyte; tumble dryer). However, since the wash-off of reactive dyes from cellulosic fibres is generally considered to present by far the greatest challenges in terms of (a) the amount of vagrant dye that must be removed (because of the characteristic poor fixation efficiency of the dye class), and (b) the difficulty of removing vagrant dye which stems from the dyes' very high inherent substantivity, which is further exacerbated because of the use of very high amounts of electrolyte in dyeing which serves to enhances dye-fibre substantivity, thereby discouraging dye removal, it is apparent that the process will be appropriate for the wash-off of all dye classes when applied to all fibre types using the novel 1:1 L:R dyeing method according to the present invention.
(201) Thus, a particular embodiment of the present invention provides a combined 1:1 L:R dyeing/two bath wash-off process which, schematically, takes the following form: Stage 1: Dye at 1:1 L:R and 65 C. for 45 minutes, then squeeze; Stage 2: First wash-off with water at 5:1 L:R and temperature of ambient up to 80 C. for 15 minutes, then squeeze; Stage 3: Second wash-off with water at 10:1 L:R and ambient temperature for 3 minutes, then squeeze and dry.
(202) When compared to conventional dyeing and wash-off processes, combined 1:1 L:R dyeing/two bath wash-off processes according to the invention allow for major savings to be achieved in terms of: Water Dyeing: Current technology: 12:1 L:R; BAT 5:1 L:R 1:1 Dyeing method: 1:1 L:R Wash-off: Current technology: 10-20:1 L:R; 3-4 stages+rinses Two bath process: 15:1 L:R total for 2 stages; no additional rinses Time Dyeing: Current technology: 90-120 minutes 1:1 Dyeing method: 45 minutes Wash-off: Current technology: 90-110 minutes Two bath process: 15 minutes Energy Dyeing: Current technology: high heating costs for large volume of water (5-12:1 L:R) 1:1 Dyeing method: low heating costs for low volume of water (1:1 L:R) Wash-off: Current technology: high heating costs for large volume of water (3-6 baths @ 10-20 L:R) Two bath process: low heating costs for low volume of water (1 bath @ 10:1 L:R) Chemicals Dyeing: Current technology: 50-100 gL.sup.1 electrolyte (@ 20:1 L:R=1000 kg electrolyte per tonne fabric); 15 gL.sup.1 Na.sub.2CO.sub.3 (@ 20:1=300 kg of alkali) 1:1 Dyeing method: zero electrolyte; 15 gL.sup.1 Na.sub.2CO.sub.3 (@ 1:1 L:R=15 kg of alkali) Wash-off: Current technology: 1-3 gL.sup.1 wash-off agent Two bath process: zero wash-off agent Wastewater Treatment Cost Dyeing: Current technology: large volume (5-12:1 L:R) with high electrolyte and alkali content 1:1 Dyeing method: low volume (1:! L:R) with zero electrolyte and low alkali content Wash-off: Current technology: large volume (10-20:1 L:R; 3-4 stages+rinses) with high electrolyte, alkali and wash-off agent content Two bath process: low volume (10:1 L:R; 1 stage; no rinses) with zero electrolyte, low alkali and zero wash-off agent content
(203) It is apparent that the two bath wash-off process according to the invention is unique insofar as it is applicable to the wash-off of all dye-fibre systems including, for example, reactive dyes/cotton, acid dyes/wool, direct dyes/cotton, etc. Surprisingly, this simple, novel approach offers the opportunity to rationalise both the many and varied dyeing methods and machinery and the wash-off methods and machinery. Clearly, the low L:R wash-off methods produce dyeings of similar wash fastness to those achieved using a conventional wash-off process which uses a proprietary wash-off agent.
(204) As previously observed, the wash-off method according to the second aspect of the invention may be combined with, and is particularly advantageously combined with, the treatment method according to the first aspect of the invention. The advantages associated with such a combination are illustrated in
(205) Throughout the description and claims of this specification, the words comprise and contain and variations of them mean including but not limited to, and they are not intended to (and do not) exclude other moieties, additives, components, integers or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.
(206) Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.
(207) The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.
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