FORM-2
THE PATENTS ACT, 1970
(39 of 1970)
COMPLETE SPECIFICATION
(See section 10; rule 13)
"An improved disperse dye levelling agent containing vegetable oil ester for dyeing of polyester fabrics with disperse dyes"
Rossari Biotech Ltd.,
An Indian Company Incorporated under
the Companies Act 1956
201-A & B, Ackruti Corporate Park,
LBS marg, Next to Great Eastern Garden,
Kanjurmarg (West), Mumbai - 400 078
Maharashtra, India
The following specification particularly describes the invention and the manner in which it is to be performed:

This invention relates to levelling agent for dyeing disperse dyes on polyester fabrics.
This experimentation deals with study of levelling properties of disperse dyes using different esters of naturally available oils such as soyabean, rice bran, cotton seed, coconut,castor oil. The levelling performance has been evaluated by studying the dyeability behavior using K/S studies, corrected absorbance and uniformity of dyeing.
Castor oil has been used in textiles to a large extent. The versatile structure that combines presence of carboxyl group, single point un-saturation and the presence of hydroxyl groups makes it an ideal raw material to produce a huge range of surfactants depending on the required application.
In textiles sulphated castor oil is used as wetting agent, popularly known as Turkey Red oil and hydrogenated castor oil used as anti- foaming agents.
One of the major application of the castor oil in textile is levelling agent. Castor oil ethoxylates act as levelling agents in polyester dyeing with disperse dyes. Literature also describe levelling agent other than castor oil. United states patent 4341526 describes improved levelling agent and a method of using it in the disperse dyeing of hydrophobic synthetic fiber materials such as polyesters and polyamides. The levelling agent described in United states patent 4341526 is based on diaryl ethers such as ditolyl ether mixed with emulsifiers and optionally a diluent which is water or an organic solvent. The study was limited to ethers.
United states patent 6,172,031 describes compositions and methods of removal of contaminants from textiles and related fabrics and garments containing at least one vegetable oil ester or fatty acid ester and a surfactant in combination with water and rinse compositions. They are also preferably employed in a method aspect comprise at least one glycol ether or glycol acetate and water.

The present invention relates to application of esters of other naturally available cheaper oils that can be used as levelling agent for polyester dyeing with disperse dyes for the improved results. The esters taken for the studies are made from following oils:
1) Soyabean Oil (SOE)
2) Rice Bran Oil (RBE)
3) Cotton Seed Oil (CSE)
4) Coconut Oil (COO)
5) Castor Oil (COE)
The above esters are used as levelling agents to carry out dyeing of polyester using disperse dyes of different energy level and compared against conventional levelling agent (CON) based on castor oil ethoxylate. The dyeing behaviors of the individual dyes are presented by using the KIS values of the exhaust dyed samples obtained at the maximum light absorption wavelengths.
Experimental Dyeing
The dyeing experiments were carried out with three different disperse dyes of different energy levels on prescoured Russian polyester woven fabric (90 denier) plain weave . The disperse dyes used in the experimental part are listed in Table I

TABLE I. Disperse dyes used in the dyeing experiments.
Energy level C.I. No. Wavelength of max. Abs. Chemical class
Low Disperse Orange
25 500 nm Azo
Medium Disperse Blue 1S3 620 nm Azo
High Disperse Blue 79 600 nm Monoazo
Disperse Orange RL 25 (LEIPropanenitrile. 3-[ethyl[4-[(4-nitrophenyl) azo]phenyl]amino]-



Disperse Blue 183 (SE) Propanamide, N-[2-[(2-bromo-6-cyano-4-nitrophenyl) aZo]-5-(diethylamino)phenyl]-
Mol. Wt.-639,41
FIGURE 1 - Structures of different energy level disperse dyes

The dyeings were carried out in laboratory-type dyeing machine (Thermal HT) at 1:10 material to liquor ratio. The weight of each fabric sample was 4 g and total dye bath volume was 40 ml. The pH was adjusted to 4.5 by acetic acid glacial and 0.5g/l anionic dispersing agent was used in the dyebath.
The dyeings were performed at 2% dye concentration on weight of fabric. During dyeing the levelling agent dosages were kept at 1 g/1 for all the types of vegetable oil esters and the conventional. Similarly the dyeing without addition of levelling agent is also carried out.
The dyeing process was started at 30°C. The temperature was increased to 80°C at the rate of 2.5°C/min and then further increased to 130°C at the rate of l°C/min. Dyeing continued for 60 minutes at 130°C. Then the dye bath was cooled down to 80°C. The fabric samples from this bath (1st bath) were taken out and then cold rinsed followed by hot rinsing separately.
The dye remaining in the dye bath (1st bath) was exhausted onto a fresh undyed piece of prescoured Russian polyester woven fabric (90 denier) plain weave using the same dyeing and washing cycle (2nd bath).
Dye dispersion
The dye dispersions were tested in a laboratory by filter test method using Whatman
filter paper No. 42
Stock solution was prepared as follows:
Disperse dyes mentioned in Table 1 -1.0 gpl
Vegetable oil esters and Conventional levelling agent - 4.0 gpl
Acetic acid - 0.5 gpl
Similarly blank solution was prepared using dyestuff and acetic acid without addition
of levelling agent. 200 ml solution from the above baths prepared was taken. The
temperature was raised to 70°C while stirring with a magnetic stirrer and was held for
15 min.
Whatman No. 42 filter paper was sandwiched between two glass plates having a
circular opening of 10mm diameter in the center. 0.2 ml of above solution was
pipetted and put on a Whatman No. 42 filter paper through the circular opening on the
glass plates.

Test Methods:
Levelling
Levelling was judged by observing the exhaust dyeing in the second bath where the dye remained in the 1st bath was exhausted. More dye depth in the second bath indicates more retarding action of a levelling agent. K/S values were determined spectrophotometrically using Premier Colourscan spectrophotometer SS5100 A for 2nd bath dyed fabrics Uniformity of dyeing
The best levelling agent is the one that gives the most uniform dyeing. For this K/S measurements were carried out for the fabrics dyed from the first bath at eight different points. The standard deviation for each of the fabric was calculated. The standard deviation measures the spread of the data about the mean value. The standard deviation is defined as the positive square root of the mean of the square deviations taken from arithmetic mean of the data.
The standard deviation is given by the formula:

σ = lower case sigma ∑ = capital sigma X = x bar
σ means 'standard deviation'. ∑ means 'the sum of.
X means 'the mean'
Corrected Absorbance
During experimentation it was observed that the levelling agent solutions had different tint value. In order to eliminate any error in absorbance reading due to the presence of this tint it was important to compensate for this tint value. This was done by measuring the absorbance of solutions with all the auxiliaries included, the measurement been done on the λmax of the dye in consideration on UV visible spectrophotometer Carry 100 Bio. This reading was subtracted from the reading of the

prepared dyebath (Auxiliaries and dyes). The resultant reading was named as corrected absorbance of the dye-bath.
Corrected Absorbance =Absorbance of dye bath with dyes - Absorbance of the dye bath without dyes
Dye Dispersion
The filter papers were dried and observed for the dispersion on filter paper. The judgement was taken on basis of even and uniform spreading of the dyestuff solution.
Results and Discussions K/S Studies:-
Ethoxylated levelling agents retard the absorption of ionic dyes on the fibre by forming water soluble complexes with the dyes. Higher is the tendency of this dyes to form a complex better is the levelling action for that levelling agent. Thus during dyeing a better levelling agent will try to hold more dye in the dyebath and lower the equilibrium exhaustion of the dye on to the polyester substrate. When this first bath is taken for the second dyeing by inserting another undyed polyester fabric in to it, the bath with the greater amount of dye will give higher depth on the fabric. Thus the better levelling agent will give deeper second bath dyeing. With this point of view the K/S values of second bath dyed fabrics were evaluated. The comparative data and graph for the K/S values of different levelling agents for the selected dyes is given below.

Levelling agent K/S
Disperse Orange RL C.I.25 Disperse Blue 2R C.I.183 Disperse Navy Blue 3G C.I.79
B 3.542 6.551 5.249
CON 7.421 13.12 11.102
RBE 15.102 27.723 21.967
SOE 8.486 14.24 12.268
COO 11.521 20.43 16.634
CSE 10.269 18.85 14.822
COE 13.258 24.143 19.283


FIGURE 2. K/S values of Disperse Orange RL C.I.25 (Low energy)

FIGURE 3. K/S values of Disperse Blue 2R C.I.183 (medium energy)


FIGURE 4. K/S values of Disperse Navy Blue 3G C.I.79 (High energy)
All the graphs consistently show a higher K/S value for RBE (rice bran ester). This
was followed by the castor oil ester.
Thus it seems that the RBE has a better retarding action than the Castor oil derivative.
In order to prove it to be a better levelling agent, the degree of levelness for the fabric
dyed in the first bath needs to be confirmed before deriving any conclusion.
Corrected absorbance:-
To further confirm the retarding action done by the different vegetable esters as
levelling agents, the dyebath after the first dyeing was taken for evaluation using the
corrected absorbance method. From the figure 5, 6 and 7 it can be seen the trend is
consistent with that observed for K/S reading for the second bath dyed fabric, with the
highest retarding observed in RBE followed by castor oil ester.

Levelling
agent Corrected absorbance
Disperse Orange RL C.I.25 Disperse Blue 2R C.I.183 Disperse Navy Blue 3G C.I.79
B 0.0198 0.0364 0.0285
CON 0.0296 0.057 0.046
RBE 0.0602 0.1128 0.0986
SOE 0.0282 0.0629 0.0474
COO 0.0421 0.0854 0.0666
CSE 0.0313 0.0815 0.0579
COE 0.0472 0:1085 0.0803


FIGURE 5. Corrected absorbance values of Disperse Orange RL C.I.25 (Low energy)

FIGURE 6. Corrected absorbance values of Disperse Blue 2R C.I. 183 (medium energy)


FIGURE 7. Corrected absorbance values of Disperse Navy Blue 3G C.I.79 (High energy)
Uniformity of dyeing:-
Standard deviation of the first bath dyed substrate, a measure of uniformity, for different dyes and levelling agents combination has been shown below. The levelling agent that will give the least standard deviation will denote the higher uniformity of dyeing as the depth of the shade will be uniform throughout the fabric.
TABLE II Disperse Orange RL C.I.25 (Low energy)

Levelling agent Mean Deviation
Blank 216.7388 3.017281
CON 210.2125 2.163433
RBE 209.315 0.860276
SOE 211.9138 2.704126
COO 215.4575 2.985736
COE 210.1363 1.531959
CSE 211.13 2.649646

TABLE III Disperse Blue 2R C.I. 183 (medium energy)

Levelling agent Mean Deviation
Blank 235.3213 3.478345
CON 230.7238 2.769774
RBE 222.185 1.306379
SOE 232.2638 3.170378
COO 234.02 3.225566
COE 228.1788 2.181527
CSE 230.925 3.022718
TABLE IV Disperse Navy Blue 3G C.I.79 (High energy)

Mean Deviation.
Blank 216.966 3.17478
CON 210.2613 2.29177
RBE 207.99 1.100284
SOE 210.9625 2.937974
COO 215.1138 3.10955
COE 210.0113 1.865566
CSE 211.3808 2.868634
It has been observed that standard deviation in K/S values is less in case of RBE followed by castor oil ester. Thus we can make a confirmatory note that the RBE is giving not only better retardation but also a more uniform dyeing as compared to other levelling agents for all the dye class.
Dye Dispersion
It has been observed that the dyestuff dispersion was better in case of RBE in all the dye classes. This further lead to the fact that the rice bran oil ester enhances the solubility of dyestuffs.
Conclusion -
From the assessment of K/S values, Uniformity in dyeing, corrected absorbance and dye dispersion it is concluded that Rice bran oil ester (RBE) is giving best results amongst all in different energy level disperse dyes.

This could be related to enhanced dye solubility with rice bran oil ester which will lead to better levelling properties as compared to conventional levelling agent and other vegetable oil esters.
Production of esters from a cheap raw material such as rice bran oil would increase the importance of these esters in a big way as a clean and alternative energy source as well.
Typically an improved disperse dye levelling agent for polyester said esters of
naturally occurring different vegetable oils comprises
a) About 10-90 parts of the vegetable oil or its fatty acid
b) About 5-60 parts of the polyethers of molecular weight ranging from 200-6000
c) About 0.05-5 parts of the catalyst like methanesulphonic acid, p-toluenesulfonic acid, Potassium hydroxide, sulfuric acid, tosic acid, Lewis acids such as scandium(III) triflate, sodium hydroxide, potassium methoxide, sodium methoxide, sodium carbonate, stannous chloride.
Advantages -
1) Alternate source to castor oil ethoxylate will be available
2) Economically viable
3) Levelling properties will be better on polyester as compared to conventional castor oil ethoxylates
4) Better reproducibility of the results
5) Better dye dispersion properties as increased dye solubility
6) Improves levelness of already dyed materials by subjecting them to higher temperatures about 130°C in the presence of improved levelling agent.

WE CLAIM:-
1. An improved disperse dye levelling agent for polyester containing vegetable oil esters.
2. An improved disperse dye levelling agent for polyester as claimed in claim 1 wherein said esters of naturally occurring different vegetable oils comprises

d) About 10-90 parts of the vegetable oil or its fatty acid
e) About 5-60 parts of the polyethers of molecular weight ranging from 200-6000
f) About 0.05-5 parts of the catalyst like methanesulphonic acid, p-toluenesulfonic acid, Potassium hydroxide, sulfuric acid, tosic acid, Lewis acids such as scandium(III) triflate, sodium hydroxide, potassium methoxide, sodium methoxide, sodium carbonate, stannous chloride.
3. An improved disperse dye levelling agent for polyester as claimed in claim1 or 2 where in the ester used is rice bran oil ester(RBE).