Knitted fabric dyeing water and surfactant

1) Dyeing and finishing water : Water source ( surface water and groundwater )

1. Surface water refers to rainwater flowing into rivers and lakes. The surface water source is sufficient, but the water quality is affected by the flow, season and surrounding environmental conditions. The content of suspended solids, sediment and other impurities in the surface water is higher, while the mineral content is less, and the water treatment is easier.

2. Groundwater well water, spring water, etc., groundwater quality is stable and clarified, but affected by geology. Often the mineral content is high, shallow groundwater contains very little suspended impurities, but contains a certain amount of soluble organic matter and more carbon dioxide. Deep groundwater refers to deep well water, which generally contains no organic matter but dissolves a lot of minerals. Water quality treatment is more difficult.

 

1. The concept of hard water and its impact on dyeing and finishing.

Hard water: Water containing soluble calcium and magnesium ions is called hard water; calcium and magnesium are expressed by hardness.

 

Total hardness: the sum of temporary hardness and permanent hardness.

Temporary hardness : The hardness expressed by the acid carbonate can be removed by boiling after precipitation.

Permanent hardness : hardness formed by chloride, sulfate or nitrate such as calcium or magnesium, which cannot be removed by boiling.

Hardness representation:

1.ppm: For one of water per million parts of calcium carbonate (CaCO ₃₎ as one ppm.

2. Dedu: 10mg of calcium oxide per liter of water , called 1 ° G hardness.

3. milligram content ( mmol ); 1 liter of calcium or magnesium per liter of water , called 1mol hardness.

★ 0~72 ppm is very soft water; 72~143 ppm is soft water;

143~215 ppm medium soft water; 215~537 ppm is hard water.

 

Practice the requirements of water quality in bleaching and dyeing

pH of 6.3 ~ 7.2

Total solids 100 mg/L

Ash 40~60 mg/L

Hardness 0~ 60 ppm (≤ 100 ppm )

Iron oxide 0.05 mg/L

Chlorine 10 mg/L

Organic matter 6 mg/L

Water softening

Chemical softening ( also known as softener method)

(1) Precipitation method : lime - pure subtraction and acid carbonate:

Ca(HCO ₃ ) 2 + Ca (OH) _{2 →} 2CaCO ₃ + 2H ₂ O

Mg(HCO ₃ )2 + Ca (OH) _{2 →} Mg CO ₃ + 2H ₂ O

MgCO ₃ + Ca (OH) _{2 →} Mg (OH) ₂ + CaCO ₃

★ Sodium carbonate, trisodium phosphate : softener, which can reduce the hardness of water by boiling.

(2) Network law:

Polyphosphate , such as sodium hexametaphosphate , acts as a softener to form a stable water-soluble complex with calcium and magnesium ions in water . It no longer has the property of hard water and does not precipitate with soap or dye.

( NaPO ₄ ) ₆ + Ca S O _{4 →} Na ₄ [Ca(PO ₃ ) ₆ ]+   N a ₂ S O ₄

Softener B or BW ( sodium ethylenediaminetetraacetate ) and softener A ( sodium ammonia triacetate ) . , Which produce a water-soluble magnesium, calcium, copper, iron and other ionic complex, high softening ability, but higher costs.

 

Ion exchange method

Ion exchange resin: An ion exchange resin is prepared by introducing an acidic or basic group into a synthetic resin.

Introducing an acidic group called a cation exchange resin, which can exchange various cations ( Ca ²⁺ Mg ²⁺ Cu ²⁺ ) in water

Introducing a basic group called anion exchange resin, which can exchange various anions in water ( SO ₄ ^2- OH ^2- )

The cation exchange resin can exchange various cations in water.

  2R — SO ₃ H + Ca ²⁺    _→ (R — SO ₃ ) ₂ Ca + 2H ⁺

It is treated with a cation exchange resin and then anion exchange resin to become ion-free water.

Cation exchange resin soft water process: cation exchange resin is acidic ( H type) and sodium type ( Na type), calcium and magnesium ions in water can be exchanged with H ⁺ or Na ⁺ respectively to obtain soft water.

Soft water process:

1. Pretreatment ; firstly, the granular cation exchange resin is charged into a softening tank, first washed or activated, that is , impregnated with saturated brine ( NaCl solution), then washed with water, and once again treated with light alkali and light acid solution. Clean again.

2. Softening : Who will clarify the purification, slowly soften the tank through the ion exchange resin at a certain flow rate, the flow rate of water can not be too fast, because the water needs to penetrate into the internal particles and ion exchange takes a certain time, the flow rate is too fast and the resin is easy to cause Ion loss, water and ion exchange tank contact time 30~60min . Sulfonic acid type cation exchange resin RSO ₃ H , softening water reaction process:

2R — SO ₃ H + Ca ²⁺    _→ (R — SO ₃ ) ₂ Ca + 2H ⁺

Who is acidic, can be neutralized by anionic alkaline exchange resin,

The knitted fabric is dyed and softened with water, and a strong acid cation exchange resin is used to soften the reaction to:

2R — SO ₃ H + Ca ²⁺    _→ (R — SO ₃ ) ₂ Ca + 2H ⁺

After a certain period of operation, the resin exchange capacity is gradually lost, and it can be regenerated with hydrochloric acid ( 4% ) or salt ( 5%~10% ) to restore its softening ability.

3. Regeneration method: firstly use water to reversely pass into the softening tank, slowly rinse the resin particles, and remove the magazine adsorbed on the particles. This is called “backwashing”. After sedimentation, it passes through the saline solution and replaces the calcium and magnesium ions with sodium ions to restore the softening ability. When the hardness of the effluent reaches the requirement, the regeneration is completed, and the regenerated liquid remaining in the ion layer is replaced by the water, that is, " Washing, the regeneration reaction is:

R ( SO ₃ ) ₂ Ca — 2 Na ⁺    _→ 2R — SO ₃ Na + Ca ²⁺

2) Structural characteristics and working principle of surfactant

Classification of surfactants

( 1 ) Anionic surfactant

(2) Cationic surfactant

(3) Amphoteric surfactants

( 4 ) Nonionic surfactants

 

2.1 The role of surfactants

2.1.1 Wetting effect

 

(1) It is better to wet than (2) , and (3) θ = 180 ° does not wet at all.

θ = 0 ° completely wet; θ < 90 ° most wet;

Most of θ > 90 ° does not wet.

 

From 0 o'clock, the line is made along the surface of the droplet, and the angle θ from the solid / liquid interface through the inside of the liquid to the tangent of the gas / liquid interface is the contact angle.

  γ S = γ SL+ γ L· COS θ or COS θ   =

2.1.2 Emulsification and dispersion

Emulsification : Disperse a liquid evenly in a very small droplet in another liquid, which is an emulsion or emulsion .

The oil is dispersed in water and is an oil-in - water type oil / water (O/W) type emulsion;

The water is dispersed in the oil and is a water-in - oil type water / oil (W/O) type emulsion.

Dispersion : A system in which a solid substance is uniformly dispersed in a liquid with very minute particles is called a dispersion or suspension .

 

2.1.3 washing effect

Fabric + dirt + detergent → fabric , detergent + dirt , detergent

 

Detergent effect diagram of detergent

(a) The oil film on the surface of the fabric (b) collapses into oil beads in the presence of a surfactant

2.1.4 Foaming effect

The system in which the gas is dispersed in the liquid is called a foam.

 

2.2 Common surfactants

2.2.1 Anionic surfactant

(1) Carboxylates

  Soap: The formula is RCOONa .

Stearic acid soap : R = -C17H35

Palmitate soap : R = -C16H33; oleic acid soap : R = -C17H33

Soap has good wetting, emulsifying and cleansing properties.   The disadvantage is that it is unstable to hard water and acid.  

(2) Sulfate sodium salt

Pancreas and bleaching T (209 detergent )

Oleic acid chloride (C17H33COCL) and sodium N - methyl taurocholate

(CH3-NH-CH2-CH2-SO3Na) reaction was prepared.

 

Function: wetting, cleaning and dispersing ability of calcium soap. Used for dyeing and silk refining.

 

(3) sulfonate

Sodium alkane sulfonate (AS)

Structural formula: C n H2 n +1SO3Na R=15 ～ 20

Has good wetting properties, certain emulsifying properties, but poor cleaning ability. It is stable to acid, alkali and hard water.

Sodium alkylbenzene sulfonate (ABS)

 

The washing ability is strong, the foam is more, but it is not durable, the fabric after washing is not pleasant, and the main component of the commercially available washing powder.

Pull open powder BX

Sodium isobutylnaphthalene sulfonate or sodium bisisobutylnaphthalene sulfonate:      

 

Good wetting and permeability, poor ability to form micelles in water, so poor cleaning ability.

Diffusion agent N ( dispersant NN0) :

a condensate of β - naphthalenesulfonic acid and formaldehyde. Has good dispersion and diffusion properties. A dispersant for reducing dye suspensions, disperse dyes, and printing paste stabilizers.  

 

 

 

2.2.2 Cationic surfactant  

(1) Leveling agent 1227 :

Leveling agent with soft, smooth and antistatic effect.

 

(2) Waterproofing agent PF :

Mainly used for waterproof finishing and soft finishing.

 

 

 

2.2.3 Nonionic Surfactants  

(1) Flat plus O ( emulsifier O , leveling agent )  

 

It has good leveling, penetrating, emulsifying and dispersing properties, and also has a certain cleansing effect.

(2) Penetrant JFC ( wetting agent EA)

C7 ~ 9H15 ~ 19O (CH2CH2O) 5H

Has good wetting and permeability properties.

Mainly used as a penetrant in desizing, bleaching, dyeing and resin finishing.

( 3 ) Cloud point of nonionic surfactant

Cloud point: an aqueous solution of a polyoxyethylene type nonionic surfactant ( concentration of 0.5 % to 2.0 % ) is slowly heated , and the temperature at which the solution changes from transparent to turbid is the cloud point of the surfactant.

2.3 HLB value of surfactant

The range of HLB values ​​of surfactants and their application properties

 

 

 

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