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[laundry chemicals] types of bleachers and application
Author
화인Tnc
Date
2019-01-18 16:40
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500
Bleaching of textile products should not be subject to extremely strong conditions (high concentration of bleaching agent, high temperature, long-term bleaching) since the damage of the product should be taken into consideration for the deterioration of the product.
1. Classifying bleachers
Bleaching agents are generally classified as oxidation bleaching agents and reducing bleaching agents. The types of bleaching agents are listed in the table below.
Oxidation bleach
1) Chloride: limestone, sodium hypochlorite, sodium hypochlorite, etc.
2) Oxygen system: hydrogen peroxide, sodium perborate, sodium percarbonate, etc.
Reducing bleach: sodium sulfate, hydro sulfide, rongarite
2. Oxidation bleacher
2.1 Chlorine bleacher
Lime (Ca (OCl) Cl): Chlorine is passed through hydrated lime Ca (OH) 2. The off-white powder is mostly dissolved in water, but if there are impurities, Ca (OH) 2 or CaCO3 remains. It is used for bleaching, disinfecting, and removing toxins.
Ca (OCl) 2 + CO2 + H2O = 2HClO + CaCO3
HClO = HCl + O causes oxygen in the generator, which is oxidized by the chlorine generated in the acid bath, and is likely to cause damage to the fiber.
Ca (OCl) Cl + H2O + 2HCl = CaCl2 + Cl2 + 2H2O
The available chlorine content of commercially available limestone is about 65 to 75% with a high purity. The following sodium hypochlorite has been used for general washing and disinfecting purposes and is not used today.
Sodium hypochlorite (NaClO): It is a colorless or light-yellow solution with chlorine in a caustic soda aqueous solution. Its bleaching action is similar to that of limestone. Commercially available products are about 5 to 6% effective chlorine.
It is used for the bleaching of cellulosic fibers such as cotton, hemp. If it is used for washing every time, it damages the fiber and the material of the washing machine is also bad. Acetate, nylon and other products may be yellowed or the dye may be discolored. To bleach the yellowing of the mattress, it is dipped at room temperature once every several months, and the rubber is brittle, so bleaching is not used.
Sodium chlorite (NaClO2): Oxidized bleached by ClO2 generated in acidic solution.
5NaClO2 + 4HCl -> 4ClO2 + 5NaCl + 2H2O
2ClO2 + H2O - & gt; 4HCl + 5O
Mainly bleached synthetic fibers such as nylon, vinylon, and polyester with pH 3 ~ 5, 70 ~ 80oC. ClO2 is a yellow-green toxic gas. Heavy metal salts are explosive and not suitable for household use.
Other p-toluene sulfone amide derivatives or chlorinated melamine bleaching agents are not used in the home.
2.2 Oxygen bleacher
Hydrogen peroxide (H2O2): Bleached by oxygen generated by weak alkaline.
H2O2 = H2O + O
It is industrially used for cotton bleaching.
sodium borate (NaBO3.4H2O)
4NaBO3 + 5H2O = 4H2O2 + Na2B4O7 + NaOH
H2O2 is released in the acid bath to exhibit strong oxidizing power.
3 Reducing bleacher
Sodium bisulfite (NaHSO3): Saturated sulfur dioxide (SO2) gas in an aqueous solution of sodium carbonate.
Na2CO3 + 2SO2 + H2O = 2NaHSO3 + CO2
NaOH + SO2 = NaHSO3
As a white powder, the aqueous solution decomposes to a pale-yellow color, which is not colorless, and produces SO2 and exhibits a reducing action. It is used for bleaching of dogs and wool.
2NaHSO3 = Na2SO + SO2 + H2O
Hydro Sulfide (Na2S2O4): A white powder that is relatively stable in air without moisture.
It exhibits strong reducing power in water, and the reaction is promoted by addition of acid or heating.
Na2S2O4 + H2O -> NaHSO3 + NaHSO2
NaHSO3 + H2O -> NaHSO4 + 2H
Rongarite, zincronin: Because of its stability, it is widely used for industrial use.
Cotton: Sodium hypochlorite and sodium perborate are easy to use.
Sodium hypochlorite: Cotton fabrics are bleached at 40 to 60 ° C for 30 minutes at a concentration of 0.4 to 1.0% (450 ppm) in a bath ratio of 1:50 and a bath concentration of 0.1% (220 ppm of effective chlorine) using a product of 5.5% effective chlorine.
Sodium hypoborate and sodium borate at a concentration of 0.1 to 2% and the other conditions are the same as sodium hypochlorite to bleach cotton fabrics. Even at very high temperatures, the whiteness does not exceed sodium hypochlorite. In addition, it is known that the concentration effect is large and practical treatment requires treatment at 60 ° C or higher. The effect of time is also considerable. Rayon: Bleaching may be performed on the cotton but it is considerably lower in strength at the time of wetting and the chemical resistance is considerably lower than that of the cotton. Therefore, care should be taken not to damage the fiber by appropriately selecting the amount of bleaching agent and processing time.
Wool: Hydrogen peroxide and reducing bleaching agents are used because chlorine bleaching agents cause yellowing of wool.
Hydrogen peroxide: A hydrogen peroxide (diluted to about 10 times when using commercially available oxypur (about 3%) is added to make a 0.3% aqueous solution in hot water at a bath ratio of 1:15 to 20 and 50 to 60 ° C) Bleaching is carried out in the bath for 1 hour.
hydrosulfide: Sodium hydrosulfide is added in an amount of 0.5 to 1.0% aqueous solution of hydrous sulfide at a bath temperature of 1: 15 to 20 and 50 to 60 ° C, bleached for 1 hour in the bath, and rinsed in hot water.
Silk: Bleached with hydrogen peroxide and hydro sulphide which is equivalent to the wool bleaching method.
Acetate
Sodium chlorite: Bleaching for 1 to 20 minutes, 30 to 60 minutes in a solution containing an amount of acetic acid in an amount of 0.2 to 0.3% solution of sodium chlorate in an amount of 0.1 to 0.2%. Wash well. Surfactants (about 0.1% solution) serving as a penetrating agent are used in combination to perform bleaching uniformly.
Hydrogen peroxide: hydrogen peroxide in an amount of about 0.3% aqueous solution at a bath ratio of 1:20, bath temperature at 60 to 70 ° C, and alkali (caustic soda or ammonia water) is added to bleach for about 1 hour in alkalinity.
Synthetic fiber: Bleached to 60 ~ 70 ℃ for general chemical resistance. When sodium hypochlorite is used, it is equivalent to acetate. Vinylon and polyester can withstand bleaching using hypochlorite.
1. Classifying bleachers
Bleaching agents are generally classified as oxidation bleaching agents and reducing bleaching agents. The types of bleaching agents are listed in the table below.
Oxidation bleach
1) Chloride: limestone, sodium hypochlorite, sodium hypochlorite, etc.
2) Oxygen system: hydrogen peroxide, sodium perborate, sodium percarbonate, etc.
Reducing bleach: sodium sulfate, hydro sulfide, rongarite
2. Oxidation bleacher
2.1 Chlorine bleacher
Lime (Ca (OCl) Cl): Chlorine is passed through hydrated lime Ca (OH) 2. The off-white powder is mostly dissolved in water, but if there are impurities, Ca (OH) 2 or CaCO3 remains. It is used for bleaching, disinfecting, and removing toxins.
Ca (OCl) 2 + CO2 + H2O = 2HClO + CaCO3
HClO = HCl + O causes oxygen in the generator, which is oxidized by the chlorine generated in the acid bath, and is likely to cause damage to the fiber.
Ca (OCl) Cl + H2O + 2HCl = CaCl2 + Cl2 + 2H2O
The available chlorine content of commercially available limestone is about 65 to 75% with a high purity. The following sodium hypochlorite has been used for general washing and disinfecting purposes and is not used today.
Sodium hypochlorite (NaClO): It is a colorless or light-yellow solution with chlorine in a caustic soda aqueous solution. Its bleaching action is similar to that of limestone. Commercially available products are about 5 to 6% effective chlorine.
It is used for the bleaching of cellulosic fibers such as cotton, hemp. If it is used for washing every time, it damages the fiber and the material of the washing machine is also bad. Acetate, nylon and other products may be yellowed or the dye may be discolored. To bleach the yellowing of the mattress, it is dipped at room temperature once every several months, and the rubber is brittle, so bleaching is not used.
Sodium chlorite (NaClO2): Oxidized bleached by ClO2 generated in acidic solution.
5NaClO2 + 4HCl -> 4ClO2 + 5NaCl + 2H2O
2ClO2 + H2O - & gt; 4HCl + 5O
Mainly bleached synthetic fibers such as nylon, vinylon, and polyester with pH 3 ~ 5, 70 ~ 80oC. ClO2 is a yellow-green toxic gas. Heavy metal salts are explosive and not suitable for household use.
Other p-toluene sulfone amide derivatives or chlorinated melamine bleaching agents are not used in the home.
2.2 Oxygen bleacher
Hydrogen peroxide (H2O2): Bleached by oxygen generated by weak alkaline.
H2O2 = H2O + O
It is industrially used for cotton bleaching.
sodium borate (NaBO3.4H2O)
4NaBO3 + 5H2O = 4H2O2 + Na2B4O7 + NaOH
H2O2 is released in the acid bath to exhibit strong oxidizing power.
3 Reducing bleacher
Sodium bisulfite (NaHSO3): Saturated sulfur dioxide (SO2) gas in an aqueous solution of sodium carbonate.
Na2CO3 + 2SO2 + H2O = 2NaHSO3 + CO2
NaOH + SO2 = NaHSO3
As a white powder, the aqueous solution decomposes to a pale-yellow color, which is not colorless, and produces SO2 and exhibits a reducing action. It is used for bleaching of dogs and wool.
2NaHSO3 = Na2SO + SO2 + H2O
Hydro Sulfide (Na2S2O4): A white powder that is relatively stable in air without moisture.
It exhibits strong reducing power in water, and the reaction is promoted by addition of acid or heating.
Na2S2O4 + H2O -> NaHSO3 + NaHSO2
NaHSO3 + H2O -> NaHSO4 + 2H
Rongarite, zincronin: Because of its stability, it is widely used for industrial use.
Cotton: Sodium hypochlorite and sodium perborate are easy to use.
Sodium hypochlorite: Cotton fabrics are bleached at 40 to 60 ° C for 30 minutes at a concentration of 0.4 to 1.0% (450 ppm) in a bath ratio of 1:50 and a bath concentration of 0.1% (220 ppm of effective chlorine) using a product of 5.5% effective chlorine.
Sodium hypoborate and sodium borate at a concentration of 0.1 to 2% and the other conditions are the same as sodium hypochlorite to bleach cotton fabrics. Even at very high temperatures, the whiteness does not exceed sodium hypochlorite. In addition, it is known that the concentration effect is large and practical treatment requires treatment at 60 ° C or higher. The effect of time is also considerable. Rayon: Bleaching may be performed on the cotton but it is considerably lower in strength at the time of wetting and the chemical resistance is considerably lower than that of the cotton. Therefore, care should be taken not to damage the fiber by appropriately selecting the amount of bleaching agent and processing time.
Wool: Hydrogen peroxide and reducing bleaching agents are used because chlorine bleaching agents cause yellowing of wool.
Hydrogen peroxide: A hydrogen peroxide (diluted to about 10 times when using commercially available oxypur (about 3%) is added to make a 0.3% aqueous solution in hot water at a bath ratio of 1:15 to 20 and 50 to 60 ° C) Bleaching is carried out in the bath for 1 hour.
hydrosulfide: Sodium hydrosulfide is added in an amount of 0.5 to 1.0% aqueous solution of hydrous sulfide at a bath temperature of 1: 15 to 20 and 50 to 60 ° C, bleached for 1 hour in the bath, and rinsed in hot water.
Silk: Bleached with hydrogen peroxide and hydro sulphide which is equivalent to the wool bleaching method.
Acetate
Sodium chlorite: Bleaching for 1 to 20 minutes, 30 to 60 minutes in a solution containing an amount of acetic acid in an amount of 0.2 to 0.3% solution of sodium chlorate in an amount of 0.1 to 0.2%. Wash well. Surfactants (about 0.1% solution) serving as a penetrating agent are used in combination to perform bleaching uniformly.
Hydrogen peroxide: hydrogen peroxide in an amount of about 0.3% aqueous solution at a bath ratio of 1:20, bath temperature at 60 to 70 ° C, and alkali (caustic soda or ammonia water) is added to bleach for about 1 hour in alkalinity.
Synthetic fiber: Bleached to 60 ~ 70 ℃ for general chemical resistance. When sodium hypochlorite is used, it is equivalent to acetate. Vinylon and polyester can withstand bleaching using hypochlorite.
