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Detergent Knowledge
Apr 21, 2017

Detergent knowledge

Synthetic detergent is a mixture of multiple components. Mainly used for household washing,

 such as: clothes, tableware, carpets, flooring and other household items to do the washing. 

The main dosage forms include powder, liquid and paste. In synthetic detergent formulations, 

in addition to as an important component of the surfactant, but also contains a large number 

of inorganic salts, a small amount of other organic additives. These substances in the washing 

process have their own special role, but have to improve the role of washing effect, it is 

collectively referred to as builders.

In the synthetic detergent surfactant accounted for about l0% to 30%, builders accounted for

 about 30% to 80%. Builders, mainly inorganic salts, such as sodium phosphate, sodium carbonate, 

sulfuric acid

First, chelating agent

Phosphate salts used as a detergent auxiliaries are commonly used as sodium tripolyphosphate 

Na5P3O10 (STPP), sodium pyrophosphate, Na6P4O13; and sometimes glass-like polyphosphoric acid 

phosphite, (NaPO3) n

Sodium tripolyphosphate commonly known as pentasodium, heavy duty detergent is the most commonly 

used additives.

Sodium and sodium silicate, and a small amount of organic builders.

Sodium tripolyphosphate (STPP) is a very effective adjuvant for controlling water hardness during 

washing, which is characterized by the ability to chelate polyvalent metal ions with water 

hardness to form water-soluble complexes. In order to prevent these metal ions from ionic 

surfactants with anionic role in the formation of insoluble dirt, deposited on the surface of

 the laundry; in aqueous solution, lmol of STPP with lmol of calcium ions to form complex Na3Ca 

(P3O10), and this A calcium soap having an anionic complex, and a decontamination effect of the

 active ingredient. Sodium tripolyphosphate also has the effect of dissolving calcium adsorbed 

on the fiber, dirt, and integrating it.

Sodium phosphate is easily adsorbed on the surface of the particles and the surface of the 

laundry, greatly increasing its surface charge to facilitate the suspension of the particles,

 to prevent the occurrence of re-deposition of particles, so for the benefit of washing.

According to the specific situation of average water hardness in China, if LAS is used as active 

agent, STPP as the main auxiliary detergent in the detergent, adding 40% to 50% of the surfactant 

when the highest decontamination efficiency, the most reasonable cost.

Phosphate is an efficient detergent auxiliaries, both chelating and decontamination, and there 

is no comparable cure.

Since the 1980s, some developed countries, rivers and lakes eutrophication, to the environment 

pollution. The determination of phosphorus content. Although this issue is still controversial, 

but many countries have promulgated the law of phosphorus. Subsequently, some countries have 

conducted studies on sodium tripolyphosphate substitutes. There are several types of substitutes.


(1) Synthetic zeolite (4A type molecular sieve)

4A zeolite skeleton in each of the oxygen atoms are adjacent to the two tetrahedron common, this 

structure of the formation of large crystal points, according to the size of the crystal cage 

diameter can accommodate different sizes of cations, and these cations have larger Of the 

mobility, can be cation exchange. In the synthesis of zeolite 4A and 13X zeolite, because the

 cage diameter for calcium and magnesium ions, it can capture Ca2 +, Mg2 + and has a good 

chelating effect, hard water softening. The disadvantage is that the dirt can not provide 

dispersion.

(2) ethylenediamine tetraacetic acid (EDTA) sodium salt

EDTA chelating calcium ion capacity is the strongest of the current softener. The disadvantage

 is that the detergent can not provide alkaline, so that fat-like soil saponification. And it

 is expensive, but it is still the most used in such chelating agents in detergent.

(3) sodium citrate

Can play a complex washing solution of calcium, magnesium ions, increase the decontamination 

force. Sodium citrate is also non-toxic and easy biodegradable advantages 4) polymer chelating 

agent

Polycarboxylic acids as a substitute for phosphates Complex high-valent metal ions in the field

 of detergents used most of the acrylic homopolymer and acrylic acid - maleic acid copolymer,

 the polymer chain contains a large number of carboxyl negative ions, Is a very promising 

integrated agent.

Second, anti-redeposition agent (anti-

The builder for preventing the function of dirt re-deposition on the washed articles is an 

anti-redeposition agent. Anti-redeposition agent Molecular characteristics: with more negative

 charge; and can be adsorbed on the dirt particles and the surface of the fabric. Thereby improving the dispersion of the dirt in the washing liquid and suspension stability. The anti-

redeposition agent is typically a polymer. Such as sodium carboxymethylcellulose (CMC), 

hydroxypropylmethylcellulose sodium (HPMC), hydroxybutylmethylcellulose HBMC), polyvinyl

 alcohol (PVA), polyvinylpyrrolidone (PVP), and polyacrylic acid PAA) and acrylic acid /

 maleic anhydride copolymer (PAA / MA).

The hydrophilic lipophilicity of the solid surface plays a decisive role in the 

anti-redeposition effect of the polymer. For example, the role of carboxymethyl cellulose

 sodium salt anti-redeposition agent for hydrophilic cotton fibers is very

Polymer anti-redeposition agent mainly has the following types.

(1) sodium carboxymethyl cellulose and other modified cellulose

The cellulose formula is:

Effective. While the hydrophobicity of the polyester fiber

Sodium carboxymethyl cellulose is a good anti-redeposition agent, generally prepared by

 reacting sodium monochloroacetate with alkali cellulose.

The viscosity and the resistance to redeposition of the sodium carboxymethyl cellulose used in

 the detergent are related to the degree of polymerization and degree of substitution of the 

cellulose, and generally require a polymerization degree of the fiber molecule of 200 to 500 

and a degree of substitution of 0.6 to 0.7 should. The degree of polymerization is too high 

dissolve too slowly, the degree of substitution is too low water solubility will affect the 

adsorption of solid and dirt surface, the degree of substitution is too high,

Sodium carboxymethyl cellulose is also excellent in water solubility and also affects the 

adsorption of carboxymethyl cellulose anion. The reason is that the negative ions of the 

carboxymethyl cellulose are adsorbed on the hydroxyl groups formed by the hydroxyl groups in 

the cellulose chain and the hydroxyl groups in the cotton fibers, and when the degree of 

substitution is too high, the number of hydroxyl groups on the chain of the cellulose units

 decreases The number of drops is not conducive to adsorption. In addition, the degree of 

substitution means that the number of units in the fiber chain is increased,

After dissolved in water, it becomes a negatively charged -COO-negative ion, which increases

 the negative charge of the polymer. In the wash solution, the solid surface and dirt are 

generally negatively charged plus the use of anionic surfactants to bring it more negative 

charge, which will cause the carboxymethyl cellulose negative ions in the solid and oil surface 

adsorption Produce a high electric repulsion and not easily adsorbed.

If the degree of substitution is moderate, if the van der Waals force (including hydrogen bonds) 

between solid or oil can overcome the repulsive force, it can be adsorbed on the surface of solid 

and soil, and exhibits anti-redeposition.

For the degree of polymerization and degree of substitution moderate sodium carboxymethyl 

cellulose in the water dissolution faster, coupled with the aqueous solution viscosity is not 

large, carboxymethyl cellulose anion easily adsorbed on the surface of solid particles, and the

 surface charge density Is added to increase the dispersion stability of the particles and 

prevent them from being deposited on the surface of the laundry.

The adsorption properties of sodium carboxymethylcellulose are also shown on the surface of 

the wash. Therefore, in addition to good to prevent the role of redeposition, the sodium 

carboxymethyl cellulose also has the role of removal of dirt. A white cloth washed with a 

detergent containing sodium carboxymethyl cellulose tends to have a higher whiteness.

Sodium carboxymethyl cellulose is used in cotton fabrics to have excellent wash aid, showing 

strong resistance to redeposition. But much less for chemical fiber and silk fabrics. For the 

synthetic fiber and blended fabric effect is not good. The main reason is that the hydrophobic 

surface of the chemical fiber fabric is strong and the sodium carboxymethyl cellulose is too 

hydrophilic, and the van der Waals force between the woven fabrics is weak and is not easily 

adsorbed.

(2) Polyvinylpyrrolidone (PVP)

Polyvinylpyrrolidone shows weak cationic adsorption of negatively charged solid particles or 

molecular groups.

Polyvinylpyrrolidone having a molecular weight of (1 to 4) x 104 has a good anti-redeposition 

effect on the chemical fiber fabric, and 0.5% to 1.0% in the detergent formulation. In the 

washing cotton fabric when its detergency and anti-re-deposition is better than sodium carboxymethyl cellulose.

(3) an acrylic polymer and an acrylic acid-maleic anhydride copolymer

Polycarboxylic acid is a promising chelating agent. At present, a large number of polyacrylic

 acid sodium salt and acrylic acid maleic anhydride copolymer.

The number of carboxyl groups and the degree of polymerization of each structural unit in the

 polymer chain determines the molecular weight of the polymer as a counterstain on the polymer.

 The molecular weight is about 4 × 103-104. In the washing process, the dirt from the surface

 of the object into the washing liquid, the polymer will be adsorbed on the dirt surface, 

increasing the negative charge on its surface to improve the dispersion of dirt in the liquid 

dispersion stability, reduce the dirt and then deposited on the solid surface The Thereby improving the washing effect.

Third, the pH regulator

(1) sodium silicate

In the detergent, sodium silicate plays a very important role. In the washing process, sodium 

silicate can provide alkaline, good buffer effect, can maintain the pH value of the washing 

solution continued at 9.5 or higher until the silicate depletion, it is very important, because 

almost all the dirt Is acidic, the pH value will reduce the washing capacity. Sodium silicate

 can also cause calcium and magnesium ions in the washing solution to form insoluble silicate

 and precipitate to soften the water, and the resulting precipitate is easily wiped with water, 

and the removed soil can be suspended in the washing solution without deposition Clothing on.

This is mainly silicate can be adsorbed on the clothing, the formation of a layer of film, but 

also in the enamel, porcelain in the formation of monomolecular film, the film has anti-re-

deposition effect. In the metal surface of the formation of metal silicate monomolecular film 

on the metal corrosion inhibition, silicate also has a good wetting and emulsifying properties, 

can make acid fouling and oil emulsification, effectively improve the washing efficiency. In 

addition, sodium silicate in the spray-dried powder, the silicate makes the hollow particles 

powder brittle, in the block synthetic detergent, the silicate material makes the material

 plastic and the appearance of uniform, and easy to squeeze.

(2) sodium carbonate

The main purpose of sodium carbonate is with sodium silicate, for the main additives for phosphorus-free detergent. But also for the hard surface of the alkaline cleaning agent.

Four, bleach

If the surface of the fabric is contaminated with vegetable pigments such as juice, tea,

 coffee and other dirt, the stains formed can not be completely removed by washing the 

detergent. Only by chemical bleaching to achieve.

Chemical bleach is a bleach that is degraded by oxidation or reduction, destroys the hair 

color system or modifies the coloring groups, degrading them into smaller water-soluble units

 and is easily removed from the fabric. Peroxide such as sodium perborate, sodium percarbonate

 and peroxycarboxylic acid is a bleaching agent commonly used in household detergents.Sodium 

borate simple molecular formula NaBO3 · 4H2O its formula: Na2 · 6H20 in solution can be hydrolyzed into hydrogen peroxide, is the most widely used bleach.

Fifth, fluorescent whitening agent

Fluorescence is a photoluminescence phenomenon. When a certain kind of light to the molecules

Fluorescent whitening agent is a class of absorption of ultraviolet light, emitting blue or 

purple blue fluorescent material. Its whitening principle: ① fluorescent whitening agent to enhance the intensity of visible light to whiten the object. Since the substance adsorbing the fluorescent whitening agent not only emits the visible light irradiated on the object, but also 

converts the invisible ultraviolet light into visible light to increase the reflection intensity

 of the object to light, and when the reflected light intensity exceeds the projection When the 

intensity of the original visible light on the object being treated, the person's eyes will feel

 the object white.

② optical light complementary color principle white light is a red, orange, yellow, green, blue, 

blue, purple seven light composition of the composite light. When the white light from the object

to be reflected in the light reflected in the blue band of light relative to the strength of the

 defect when the eyes will feel the color of the object turns yellow. In the detergent by adding

 fluorescent whitening agent, because the fluorescent whitening agent will be issued blue or 

blue-violet fluorescence, just fill the blue light defects, leaving the goods back to white.

The fluorescent whitening agent used in the washing has a wavelength of 300 to 400 nm and an

 emission wavelength of 400 to 500 nm. This blue or blue-purple light is exactly the same as 

the yellow light, and the items are whitened.

    There are many types of fluorescent whitening agents, of which the most important is 

stilbene. Washing fluorescent whitening agent is a direct dyeing, can directly whitening 

fabric.

Six enzymes

Enzymatic detergents are products that are formulated with enzymes of different functions, 

such as amylase, lipase and cellulase, in detergent.

An enzyme is a biocatalyst present in an organism. Such as lipase, the role of human fecal

 dirt, such as the main ingredient in the collar dirt, is the decomposition of these soils 

into glycerol and fatty acids.

The decomposed glycerol is readily soluble in water and the fatty acid is easily removed by 

the "crimping" process of the oil by the oil.

Cellulase and the role of several enzymes are different, cotton cloth after wearing and 

repeated washing, the fiber surface will appear fine hair, this fiber fine hair can be seen 

under the microscope, they can lead to hardening clothing cotton material The feel, fine 

fibers can win over dirt, is the formation of colored clothing stains reasons.

Cellulase is able to break down the microfibers that appear on the surface of cotton fibers

 to improve the washing effect and improve the feel of hardened cotton fibers. It is soft and 

has a bright color. The various enzymes used in the current washing are added to the detergent

 in the form of granules.

Seven, fillers or adjuvants

1. Fillers

The presence of sodium sulfate is beneficial for washing. It has the effect of reducing the

 CMC value of the surfactant and improving the surface activity of the surfactant and

 promoting the adsorption of the surfactant to the surface of the particle and the laundry, 

increasing the dispersion stability of the particles and preventing the deposition. Improve

 the washing efficiency, in addition to the presence of sodium sulfate powder detergent will 

become loose, good mobility. But also can make the product price decline, and maintain the

 balance of components.

2. Solvents

Urea (H2N-CO-NH2) as a liquid detergent solvent for the preparation of toothpaste, can inhibit 

the breeding of lactobacilli, and can dissolve the tooth surface of the film.

3. Anti-caking agent

Sodium p-toluenesulfonate (CH3-C6H6-S03Na) is mixed with powdered detergents, and the anti-caking 

properties are all good and have good feel.

Antistatic agent

In liquid detergents, often need to add antistatic agent, so that the washing material to 

eliminate static electricity. Generally, surfactants that can be used as softeners are also

 good antistatic agents, such as cationic surfactants, and zwitterionic surfactants can be

 used as antistatic agents. In anionic surfactants, various phosphates are good antistatic agents.

The dimension has little effect. While cellulose ether。



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