Preparation and Application of Sodium Percarbonate As Bleaching Agent for Cotton Fabric

Indian Journal of Textile Research Vol. 6, December 1981, pp. 151-153

Preparation and Application of Sodium Percarbonate as Bleaching Agent for Cotton Fabric

EM ABDEL-BARY, M M MOSTAFA* & S EL-BAZZA Chemistry Department, Faculty of Science, Mansoura University, Egypt Received 30 July \979; accepted 24 July \98\

A new method has been developed for the preparation of sodium percarbonate for use as a bleaching agent for coloured and white textiles. The maximum stabilization of sodium percarbonate is obtained with 2.2% crystalline magnesium sulphate and 1.2% sodium silicate.

Sodium percarbonate is an important bleaching agent Results and Discussion for coloured and white textiles1 -3. Methods of The main parameters which can affect the preparation and the conditions for getting maximum stabilization of hydrogen peroxide in sodium bleaching efficiency with this compound are covered percarbonate are: (1) type and amount of stabilizer, (2) by patents4 -7 which do not give full information amount of water, and (3) amount of sodium about its preparation and application conditions. In percarbonate. While studying the effect of both the the present paper, a new method for preparing sodium type and amount of stabilizer, all other parameters percarbonate and the conditions for its application as a were kept constant. It was found that increase in the bleaching agent for cotton fabrics have been described. quantity of sodium silicate or magnesium sulphate used up to 0.14 and 0.12 g respectively increases the Experimental Procedure amount of hydrogen peroxide which reacts with 109 Preparation of sodium percarbonate - Sodium sodium carbonate. Further increase in the quantity of percarbonate was prepared by mixing sodium sodium silicate has no effect, while increase in the carbonate (10 g)and sodium silicate (0.175 g)in 17.5ml quantity of magnesium sulphate decreases the amount bidistilled water. To the cold mixture, 20 ml hydrogen of combined hydrogen peroxide. Better results were peroxide (30% wt/vol) containing '0.325 g magnesium obtained by using a mixture of 0.325 g magnesium sulphate heptahydrate was added and the slurry of sulphate and 0.175 g sodium silicate (Fig. 1). Sodium

sodium percarbonate formed was dried in an oven at 4"4408

151 INDIAN J. TEXT. RES., VOL. 6, DECEMBER 1981

~ E 0 C B A DABAVERAGECOPPERDEGREEFlUIDITYE OFNUMBER WETTABIUTY WHITENESS percarbonate so obtained contained 30.8% stabilized 0~~STABILIZED A 88 ~ X[;"C r-- hydrogen peroxide at room temperature. The 92r • 8480 formation of colloids by silicate hydrolysis inhibits the catalytic effect of metal ions present in sodium carbonate and maintains the pH value at 10-11. This 80 0·16020·1012 8~ 24 indicates the importance of adding sodium silicate as a50400 0'86030201070 Q.Q6004 0·14 7r- 21 stabilizer. Also, magnesium hydroxide (obtained by 6~ 18 the hydrolysis of magnesium sulphate) assists the 5~ 15 precipitation of heavy metal ions, res~lting in improved stability of sodium percarbonate. 4r- 12 r- 76

Effect of water-Only a small amount of bidistilled "K....'X.....:. X water should be used in the preparation of sodium 23t 9t6 6872 .~.~ B percarbonate. Excess water accelerates the decom• E position of hydrogen peroxide 12. If the amount of oL 03t 6064 water is less than that required, a part of sodium 1 2 3 4 5 CONCE NT RATION,g/Iitre carbonate remains suspended without reacting with Fig. 3-ElTect of concentration of sodium percarbonate hydrogen peroxide. The maximum stabilization is on fabric characteristics obtained by using 17.5 ml bidistilled water. Effect of sodium carbonate-The optimum ratio of matters in the fabric without scission of the cellulosic the quantities of hydrogen peroxide and sodium chains. The rate of decomposition of hydrogen carbonate is 5: II; about 4.7 g hydrogen peroxide peroxide increases with increase in temperature and it reacts with 10 g sodium carbonate. The optimum reaches its maximum value at 90°C. The wettability of quantity of sodium carbonate is 109. the fabric also improves. Bleaching of cotton fabric with sodium Both the fluidity and copper number remain percarbonate-Sodium percarbonate which contains unaffected after bleaching for 2 hr. However, the 65.8% sodium carbonate, 30.8% stabilized hydrogen increase in bleaching period in alkaline medium at perox.ide, 1.16% crystalline magnesium sulphate and 95°C causes partial hydrolysis of the cellulosic chains. 1.1% sodium silicate can be used as a bleaching agent. Also, the degree of whiteness improves and it is not The main parameters which govern the bleaching dependent on the bleaching period. process, such as temperature, period of bleaching and The relationships between copper number (NcJ, the concentration of sodium percarbonate, have also fluidity (F) and the concentration of sodium been studied. percarbonate (Cpc) are shown in Fig. 3 and can be The effect of temperature on the characteristics of expressed as follows: the bleached cotton fabric is shown in Fig. 2. The degree of whiteness improves and reaches its Ncu m Cpc+ K maximum value of 86.5(in comparison to 62.5 for grey F = m Cpc+ k fabric) at 100°C without any change in fluidity and copper number. This means that the oxygen released The values of m, m, K and k are found to be 0.19, from sodium percarbonate destroys the coloured 0.76, 0.003 and 2.1 respectively. This illustrates that

-- CCPPER NUMBER both copper number and fluidity increase with increase E 242118151227BC76rOL0A A...80\l590.•.85 0C 60DEGREEFlUDITY OF WHITENESS 35 8 \I 75 " 0 B in the concentration of sodium percarbonate. The ~ TEMPERATURE,67 r ·C 4 H202SAVERAGE3 TA8ILIZED 64 WETTA8lUTY OL 2 degree of whiteness and wettability improve with Fig. 2-ElTect of temperature152 on fabric properties I[ increase in sodium percarbonate concentration. It follows that in contrast to the conventional bleaching agents, sodium percarbonate is relatively stable during storage at room temperature up to 5months in an open vessel. However, the content of hydrogen peroxide decreases from 30.8 to 26.0%.

References I Takashi S, Yoshio M & Mashairo M, Japan Pat 7,107, 371 (to 100 Japan Peroxide Co. Ltd), 24 Feb. 1971; Chem Abstr, 75 (1971) 38564 Y. 2 Riyouichi M & Takashi F, Germ Offen 2,420,561 (to Kao Soap Co. Ltd) 30 Oct 1975; Chem Abstr, 84 (1976) 19570 s. ABDEL-BARY et al.: SODIUM PERCARBONATE AS A BLEACHING AGENT FOR COTTON FABRIC

} Fumikatsu T & Takehiko K, Japan Pat 7,592,870 (to Kao Soap 6,734,899 (to Toyo Soda Manufacturing Co. Ltd) 24 March Co. Ltd) 22 July 1975; Chern Abstr, 84 (1976) 137624 k. 1976; Chern Abstr, 85 (1976) 145328 c. 4 Madhusudan J, Gerrn Offen 2,344,017 (to du pont de nemours, 8 Clibbens D A & Geaka A, J Text Inst, 15 (1924) 27. E.I., and Co.) 7 March 1974; Chern Abstr, 81 (1974) 65749 t. 9 Farrow F W & Neak S M, J Text Inst, 15 (1924) 157. 5 Milton S, US Pat 3,801,706 (to Allied ChemiCal Corp) 2 April 10 Egyptian Standard: 121 (l96\). 1974; Chern Abstr, 81 (1974) 65750 m. II Vogel A I, Quantitative inorganic analysis (Longmans Ltd, 6 Richard E H & Suchilk B, US Pat 3,870,783 (to FMC Corp) II London) 1961. March 1975; Chern Abstr, 83 (1975) 30439 f. 12 Etienne A & Zumbrunn J P, Fr Pat 1,367,499,24 July 1974;Chern 7 Yoshiki N, Kyoichi H, Takashi S & Terashi M, Japan Pat Abstr, 62 (1965) 3687 c.