WO2005007791A1

WO2005007791A1 - Laundry detergent composition

Info

Publication number: WO2005007791A1
Application number: PCT/KR2003/001455
Authority: WO
Inventors: Seung-Hak Baik; Jae-Hong Lee
Original assignee: Clenvi Co., Ltd.
Priority date: 2003-07-22
Filing date: 2003-07-22
Publication date: 2005-01-27
Also published as: AU2003257616A1

Abstract

The object of this invention is to provide a laundry detergent composition, which includes 75-90 wt% (hereinafter, the total weight of the laundry detergent composition is set as the basis) of powder consisting of sodium sesquicarbonate and layered silicate mixed with each other in a weight ratio of 65:35-95:5,5-10wt% of surfactant, and 0-20 wt% of additive typically applied to a laundry detergent. The present invention provides an invironmentally friendly and nonpolluting detergent composition, which has detergentcy that is the same as or superior to a conventional detergent even though it contains a minimum amount of surfactant.

Description

LAUNDRY DETERGENT COMPOSHION

Technical Field

The present invention relates to a laundry detergent composition. More particularly, the present invention pertains to an environmentally friendly and nonpolluting laundry detergent composition, which employs sodium sesquicarbonate and layered silicate as a builder instead of phosphoric acid and zeolite, thereby assuring excellent detergency even though it contains a small amount of surfactant.

Background Art

Generally, a laundry detergent is required to have excellent detergency when applied to laundry and must not generate wastewater which pollutes the environment Accordingly, much effort has been made to develop a nonpoUuting detergent. For example, a detergent made of a vegetable surfactant and a detergent made of waste oil have been developed. However, the vegetable surfactant is problematic in that since it is difficult to extract the surfactant from a plant, assurance of a sufficient amount of surfactant is not easy. Furthermore, the detergent employing the waste oil is problematic in that use of the detergent is inconvenient because it is difficult to provide the detergent in powder form. Therefore, some of the study of nonpolluting detergent has been directed toward reducing the content of the surfactant and maximizing the performance of a builder. Korean Pat. Laid-Open Publication No. 2001-0082782 discloses that cationic, anionic, and/or nonionic surfactants are used in an amount of about 10 - 45 % based on the total weight of detergent composition, and a builder, such as sodium tripolyphosphate as a phosphorus compound, aluminosilicate-based 4A zeolite, sodium mtrilotriacetate, sodium carbonate, sodium bicarbonate, sodium sesquicarbonate, sodium sulfate, sodium silicate, layered silicate, Burkeite, and citrate, is used in an amount of about 35-75 % based on the total weight of the detergent composition. Sodium sesquicarbonate and layered silicate are popular choices for the builder in current studies of nonpoHuting detergent Sodium sesquicarbonate has some advantages such as having excellent detergency and being nonpoUuting. Another advantage is that it has a weak aU aline pH, thereby rrrinimizing damage to a fiber. Usually, layered silicate has a structure provided in two- dimensional sheets, that is to say, δ-sheet structure. Since various sizes of inorganic ions can be exchanged between the sheets and organic polymer materials can be inserted between the sheets, layered silicate is desirably capable of removing hardness components from water and has excellent soφtivity to contøπiinants during a washing process, and thus, it has physical properties suitable as a builder for detergent. Furthermore, since it has excellent capability to enable oil to be absorbed into a surfactant, the amount of surfactant used in a detergent may be reduced during a compounding of the detergent. Particularly, when layered silicate is used as the builder for detergent, disadvantages of aluminosilicate zeolite A, which was frequently used as the builder for detergent after the commercial use of sodium tripoly phosphate (STPP) was restricted, can be avoided, that is to say, there can be avoided the disadvantages that ions having a large hydrated radius, such as magnesium ions, are scarcely removed, even though the removal ability of calcium ions constituting hardness components from water is excellent, because a size of a cavity is constant; and zeolite particles which cause alkalinity because they are insoluble in water are deposited in fiber gaps, thereby damaging the fiber and affecting humans, and deposited in operating parts of a washing machine, increasing abrasion in the washing machine. Accordingly, layered silicate is in the forefront as a substitute. Furthermore, it is possible to produce a compact detergent according to the world-wide trend, and thus, it attracts considerable attention as an auxiliary substance for detergent capable of contributing to the protection of the environment. The above components are known as an auxiliary substance for detergent of the next generation because of excellent detergency and nonpoUuting characteristic, and are suggested as components constituting a detergent in many documents. U.S. Pat. No. 5,756,445 discloses a granular detergent composition which contains 20 - 50 wt% of aluminosilicate (low bulk density component) and 10 - 50 wt% of mixture of layered silicate and sesquicarbonate (high bulk density component). British Pat No. 2315762 describes a detergent composition which contains dicarboxylic acid in conjunction with sesquicarbonate and/or layered silicate as an alkaline source. The Korean Pat. Laid-Open Publication No. 2001-0082782 discloses a detergent composition which includes sodium bicarbonate, anhydrous soda ash, water, synthetic surfactants, silica, sodium silicate, neutral salts, and powder containing a large amount of sesquicarbonate produced from a polymer dispersing agent. The present inventors mixed and reacted aqueous solutions, in which sodium bicarbonate and sodium silicate are homogenized in water, with each other to produce slurry, dried the slurry to produce powder, and analyzed the powder using an XRD, resulting in the surprising finding that the powder consists of layered silicate and sodium sesquicarbonate. Particularly, SEM (scanning electron microscope) analysis of the powder confirmed that detected sodium sesquicarbonate has desirable qualities of crystalline structure, particle size and density even though a seed nucleus or an anionic surfactant is not employed. Thereby, the present inventors filed for a process of simultaneously producing sodium sesquicarbonate and layered silicate on January 23, 2002 with the Korea Industrial Property Office, which is disclosed in pending Korean Pat Application No. 10- 2002-0003998.

Disclosure of the Invention . Accordingly, an object of the present invention is to provide an environmentally friendly and nonpoUuting laundry detergent composition, which employs only layered silicate and sodium sesquicarbonate as buUders without employing other substances as builders, thereby niinirnizing surfactant content and assuring exceUent detergency. In order to accompUsh the above object, the present invention provides a laundry detergent composition which includes 75 - 90 wt% (hereinafter, the total weight of the laundry detergent composition is set as the basis) of powder consisting of sodium sesquicarbonate and layered si cate mixed with each other in a weight ratio of 65:35 - 95:5, 5 - 10 wt% of surfactant, and 0 -20 wt% of additives that are typically appUed to a laundry detergent.

Brief Description of the Drawings

FIG. 1 is an XRD analysis graph of a powder sample produced according to the present invention; and FIG. 2 is an SEM picture of the powder sample produced according to the present invention.

Best Mode for Carrying Out the Invention

Sodium sesquicarbonate and layered silicate appUed to a laundry detergent composition of the present invention may be produced according to pending Korean Pat. AppHcation No. 10-2002- 0003998 developed by the present inventors. Sodium bicarbonate and sodium silicate are used as a starting material in the course of producing sodium sesquicarbonate and layered silicate. TypicaUy, sodium carbonate (Na CO₃) is carbonated to produce sodium bicarbonate (R.N. Shreve et al., Chemical Process Industries, McGraw-Ffill Book Co., 4* ed., 1977, p.213). A commercial method of producing sodium bicarbonate includes dissolving soda ash (hydrated mineral matter mostly consisting of Na C0₃) in aqueous Uqui4 putting the resulting saturated solution of soda ash in a carbonation vessel to simultaneously cause the solution to come into contact with carbon dioxide gas and cool the solution. After aqueous slurry is recovered and filtered in the carbonation vessel, it is dried to produce sodium bicarbonate crystals. AdditionaUy, sodium bicarbonate may be produced from a trona ore (coarse sodium sesquicarbonate) through a multi-stage purifying process. Such aproduction is disclosed in U.S. PatNos.2,346,140,2,639,217, 3,028,215, 3,780,160, 6,207,123, and 200/0001037, and Chinese Pat. No. 1270926. Sodium silicate is produced by reacting a mixture of sUica with soda ash or caustic soda at 1200 ^°C or above, consists of SiO and Na O, and forms various compounds according to the relative proportion of the above two components. It is usuaUy classified into a crystal type and an amorphous type, and amorphous-type siUcate is exempUfied by sodium metasiUcate, sodium orthosiUcate, and sodium sesquisiUcate, which respectively contain SiO and Na O mixed in a molar ratio of 1 : 1 , 1 :2, and 2:3, and first to fourth Uquid sodium silicates which contain from 30 % to 50 % water corresponding to a ratio of SiO from 2 to 4. Commercial Uquid sodium silicate contains SiO₂ and Na₂O mixed in a ratio of about 2 -4 : 1. Preferably, sodium silicate contains SiO₂ and Na O mixed in a ratio of 2.1 — 3.8 : 1. In the middle of the process according to the present invention, an amount of water may be controUed to prevent formation of lumps which are considered an obstruction to the process, thereby increasing yield. According to a preferable aspect of the present invention, a ratio of soUds to water is maintained at about 50 - 70 % in mixed Uquid of sodium bicarbonate with sodium siUcate. In this regard, since sodium siUcate essentiaUy contains water, the amount of water added in practice is less than 50 - 70 %. When the amount of water is smaU, a large amount of anliydrous soda ash may be generated. On the other hand, when the amount of water is large, the reaction of sodium siUcate with sodium bicarbonate may be hindered. In other words, when separate reactions of sodium siUcate and sodium bicarbonate occur, sodium siUcate forms a transparent crystal and sodium bicarbonate is dissolved in water. Sodium bicarbonate aqueous solution reacts with sodium siUcate aqueous solution, and the resulting solution is dried to produce powder consisting of sodium sesquicarbonate and layered siUcate appUed to the detergent composition of the present invention (FIG. 1). Sodium sesquicarbonate is expressed as an experimental equation of NaCO₃* NaHCO₃* 2H₂O, and is a crystal having an acicular structure in a powdery state. Layered siUcate may be expressed as a Formula of NaMSi_xO₂₊₁ • yH₂O (wherein, M is sodium (Na) or hydrogen (H), x is 1.9 - 4, and y is 0 - 20). In the process according to the present invention, when the sodium bicarbonate aqueous solution reacts with the sodium siUcate aqueous solution, a reaction temperature is preferably about 100 ^°C or above. The reason for this is that when the reaction temperature is about 100 ^°C or below, the yield of layered siUcate may be significantly reduced. On the other hand, when the temperature is about 150^°C or above, layered siUcate is generated but sodium sesquicarbonate may be decomposed. Accordingly, it is preferable that the reaction temperatures of the sodium bicarbonate and sodium siUcate aqueous solutions of the present invention be about 100 - 150^°C. Reaction times of the sodium bicarbonate and sodium siUcate aqueous solutions depend on temperature, and may be easily determined through repeated experimentation mcurring no expenses to those skϋled in the art According to a preferred aspect of the present invention, when the reaction is carried out at 125 ^°C for 1 - 1.5 hours, a high yield results. Slurry of sodium bicarbonate and sodium siUcate mixed according to the present invention may be conveniently dried by heating. Alternatively, drying may be conducted in spray and belt manners, which are weU known in the art and may be desirably appUed to the present invention. The reaction of sodium bicarbonate and sodium siUcate by heating in an aqueous solution is achieved according to the foUowing Reaction Equations. First, sodium bicarbonate reacts according to the foUowing Reaction Equations 1 and 2.

Reaction Equation 1 NaHCO₃ → Na⁺ +HCO₃- Reaction Equation 2^' 2HCO₃- → H₂O + CO₂

The above reactions scarcely occur in aqueous solution at room temperature, but are actively carried out at 60 ^°C or above. CO generated in Reaction Equations 1 and 2 reacts with sodium siUcate as Mows. At this time, CO is a main component initiating a reaction of Reaction Equation 3. Reaction Equation 3 Na₂O^» 2SiO₂ + CO₂ + 4H₂0 → Na₂CO₃ + 2Si(OH)₄ wherein, Na₂CO₃ reacts with water to produce Na CO₃ ^• H O.

Reaction Equation 4 Na₂CO₃ +H₂O → Na₂Cty H₂O

Na₂CO₃ ^» H₂O produced through Reaction Equation 3 reacts with NaHCO₃ which is not decomposed by Reaction Equations 1 and 2 to produce products of Reaction Equation 5.

Reaction Equation 5 Na₂CO₃* H₂O+NaHCO₃+H₂O →Na₂CO₃ ^• NaHCO₃- 2H₂O Sodium sesquicarbonate is produced in Reaction Equation 5, and a combination of Reaction

Equations 4 and 5 is as Mows.

Reaction Equation 6 Na₂CO₃+NaHCO₃+2H₂O→Na₂CO₃ ^» NaHCQj- 2H₂O

Since Si(OH)₄ produced in Reaction Equation 3 is very unstable, it is combined with other Si(OH)₄ to form disiUcic acid. Reaction Equation 7 OH OH

OH- Si- ^■OH OH- -Si- •OH

OH OH OH OH

OH Si -Si OH + H∑O

OH OH DisiUcic acid of Reaction Equation 7 is combined with Na ions existing in an excessive amount in Reaction Equation 1 to produce layered siUcate. In this regard, when the temperature is 100 ^°C or below, layered silicate is not produced. If anhydrous soda ash is appUed to this reaction, the amount of soda ash is excessively increased in conjunction with soda ash generated from sodium siUcate according to a reaction mechanism, and thus, a portion of anhydrous soda ash which does not participate in a sodium sesquicarbonate combination is generated in an excessive amount AdditionaUy, a probability of a reverse reaction of Reaction Equation 3 increases. Alternatively, sodium bicarbonate and sodium siUcate may be separately produced in aqueous solution and then mixed with each other, or sodium bicarbonate and sodium siUcate may be added into water to initiate the reaction before they are produced in separate aqueous solutions. However, these procedures are disadvantageous in that it is difficult to conduct the reaction and the yield may be reduced when they are produced in a great amount. Sodium sesquicarbonate and layered siUcate according to the present invention are used in an amount of 75 - 90 % based on the total weight of the detergent composition of the present invention. At this time, a ratio of sodium sesquicarbonate and layered siUcate is 65:35 - 95:5 based on the weight. In the case of powder consisting of sodium sesquicarbonate and layered siUcate produced according to the above procedure, a ratio of sodium sesquicarbonate and layered siUcate is about 65:35 - 95:5. A surfactant avauable to the detergent composition according to the present invention is exempUfied by a soap surfactant, an anionic surfactant and/or a nonionic surfactant An amount of the surfactant used is 5 — 10 % based on the total weight of the detergent composition. When the amount of the surfactant is 5 % or less, the influence of the surfactant is negUgible, and thus, it is impossible to obtain desired detergency. The surfactant may be used in an amount of 10 % or more, but it is preferable that the amount be 10 % or less to provide environmentaUy friendly and nonpoUuting properties. More preferably, the amount is 7 % or less. With respect to this, it is proved that it is possible to gain desirable detergency by employing sodium sesquicarbonate and layered siUcate according to the present invention even though the surfactant is used in an amount of 10 % or less, and if the surfactant is used in an amount of 10 % or more, detergency is not significantly improved in comparison with the case of using the surfactant in an amount of 5 - 10 %. Non-Umiting, iUustrative examples of the anionic surfactant are any one selected from the "^{' *} group consisting of a straight-chain type of alkyl sulfόriate Rn-CH₂-O-SO₃Na n=12-16), alkane sulfonate (Rn-SO -Na n=12-18), alpha-olefin sulfonate (Rnl-CH= H-Rn2-SO₃Na), and a mάxture thereof, and it is used in an amount of 1 - 10 % based on the total weight of the detergent composition. Since most anionic surfactant contains a sulfur component, it causes denaturation of protein and is toxic, and thus, it is preferable to use the anionic surfactant in as smaU an amount as possible, for example in an amount of 3 % or less, so as to assure environmentaUy friendly and nontoxic properties. IUustrative, but non-Umdting examples of the nonionic surfactant include poly(oxyethylene) (POE) amine, POE fatty acid ester, polyethylene glycol, polyethylene glycol fatty acid ester, poly(oxyethylene) fatty acid alcohol ether, a condensate of poly(oxyethylene) and poly(oxypropylene), and sorbitan fatty acid ester. Its amount is 3 - 10 % based on the total weight of the detergent composition. Preferably, the amount of the nonionic surfactant is more than that of the anionic surfactant. The reason for this is that a predetermined amount of the anionic surfactant remains on clothes even after being washed, affecting humans, and in practice the nonionic surfactant has superior detergency compared to the anionic surfactant. Non-Urniting, Ulustrative examples of the soap surfactant include a fatty acid (RnCH₂-CO₂Na n=8-18), whose content in the detergent composition is 2 - 5 % based on the total weight of the detergent composition. Since the soap surfactant is environmentaUy friendly because it employs a natural raw material but has poor detergency, it cannot be used in a large amount, but it is preferable to use it in conjunction with other surfactants. The detergent composition of the present invention may further contain a bleaching agent, an enzyme, a dispersing agent (acryl-based), a perfume or the like in an amount of 5 - 20 wt%, and the amount of each component used is weU known to those skiUed in the art An oxidation bleaching agent which conducts the bleaching by use of oxidizing power is frequently used as the bleaching agent, and is exempUfied by hydrogen peroxides (H₂O ), such as sodium percarbonate (2Na CO₃* 3H₂Q₂) and sodium perborate (NaBO ^» H O₂ ^» 3H₂O). Sodium percarbonate is most often employed The enzyme is exempUfied by neutral and alkaUne protease, Upase, cutinase, esterase, amylase, pectinase, lactase, peroxidase, and ceUulase. Protease functions to decompose contaminated protein in humans, and commercial protease may be used in the present invention. Examples of commercial protease include Primase (Novo Industries A/S), Maxapem (Gist-Brocades), and Optimase and Opticlean (Solvay Enzymes). An amount of protease used is about 0.0001 - 3 % based on the total weight of the detergent composition. Lipase serves to decompose human Upids, and may be obtained from fungi and baciUus, such as Humicola, Thermomyces, or Pseudomonas species. Alternatively, commercial lipase may be used. Examples of commercial Upase include Lipolase

(Novo Industry A/S). An amount of Upase used is about 0.0001 - 2 % based on the total weight of the detergent composition. Amylase serves to decompose external contaminated starches. TJlustrative, but non-Umiting examples of amylase include commercial Rapidase (Gist-Brocades), and Termamyl and BAN (Novo Industries A/S). FinaUy, ceUulase functions to decompose a fibroid material, thereby removing fluffs from clothes made of natural cotton. CeUulase avaϋable to the present invention may be obtained from any baciUus or fungi type which has an optimum pH within a range of 5 - 9.5. U.S.

Pat. No. 4,435,307 discloses fungal ceUulase from Humicola insolens or Humicola strain DSM 1800, ceUulase 212 generated from fungi belonging to the Aeromonas genus, and ceUulase extracted from a hepapancreas of DolabeUa Auricula Solander, that is, an oceanic moUusk, as ceUulase avaUable to the present inventioa Furthermore, ceUulase avaUable to the present invention is disclosed in British Pat. Nos. 2,075,028 and 2,095,275, and Germany OS 2,247,832. All of the above ceUulases may be appUed to the detergent according to the present invention. Non-Umitiiig, iUustrative examples of the dispersing agent include acryl polymers, which assure high water softening property, dispersibiUty, detergency, biodegradabUity, and heavy metal chelating property. An amount of the dispersing agent used is about 0.0001 - 2 % based on the total weight of the detergent composition. The detergent composition according to the present invention may be provided in various forms, such as powder, granule, tablet, bar, and Uquid. The forms may be easUy achieved by adopting technology typicaUy used in the detergent field. The Uquid detergent composition may contain water and misceUaneous solvents, such as carriers. Primary alcohol or secondary alcohol having a low molecular weight (e.g. methanol, ethanol, propanol, and isopropanol) is suitable. Monohydric alcohol is proper for a soluble surfactant, but polyol having a carbon number of about 2 - 6 and about 2 - 6 hydroxyl groups (e.g. 1,3-propandiol, ethylene glycol, glycerin and 1,2-propandiol) may be used. The carrier may be used in an amount of 5 - 90 %, typically 10 — 50 % based on the composition. The detergent composition of the present invention is preferably formed as described above during a washing process employing water, and washing water has a pH of about 6.5 - 11, and preferably about 7.5 - 10.5. Laundry generally has a pH of 9 - 11. A technology of controUing pH when they are used in a predetermined amount adopts the use of a buffer solution, aUcaUne acid and the like, which is known to those skilled in the art A better understanding of the present invention may be obtained through the foUowing examples and experimental examples which are set forth to iUustrate, but are not to be construed as the limit of the present invention. Production of a raw material

EXAMPLE 1 273 g of sodium bicarbonate was mixed with 150 mi of water to produce a homogeneous solution, 727 g of first Uquid sodium siUcate (SiO₂:Na₂O = 2.11:1) was mixed with 750 mi of water, and the resulting solutions reacted with each other in a reactor at 125 ^°C for 1.5 hours to produce slurry containing 50 - 70 % of water. The slurry was dried to produce white powder. EXAMPLE2

345 g of sodium bicarbonate was mixed with 200 mi of water to produce a homogeneous solution, 655 g of first Uquid sodium siUcate (SiO₂:Na₂O = 2.11:1) was mixed with 750 mi of water, and the resulting solutions reacted with each otlier in a reactor at 125 ^°C for 1.5 hours to produce slurry containing 50 -70 % of water. The slurry was dried to produce powder.

EXAMPLE 3

376 g of sodium bicarbonate was mixed with 300 mi of water to produce a homogeneous solution, 624 g of first Uquid sodium siUcate (SiO₂:Na O = 2.11:1) was mixed with 750 mi of water, and the resulting solutions reacted with each other in a reactor at 125 ^°C for 1.5 hours to produce slurry containing 50 - 70 % of water. The slurry was dried to produce powder.

EXAMPLE 4

429 g of sodium bicarbonate was mixed with 300 mi of water to produce a homogeneous solution, 571 g of first Uquid sodium siUcate (SiO₂:Na₂O = 2.11:1) was mixed with 600 mi of water, and the resulting solutions reacted with each other in a reactor at 125 ^°C for 1.5 hours to produce slurry containing 50 - 70 % of water. The slurry was dried to produce powder.

EXAMPLE 5

385 g of sodium bicarbonate was mixed with 300 mi of water to produce a homogeneous solution, 615 g of second Uquid sodium silicate (SiO₂:Na₂O = 2.35:1) was mixed with 700 mi of water, and the resulting solutions reacted with each other in a reactor at 125 ^°C for 1.5 hours to produce slurry containing 50 - 70 % of water. The slurry was dried to produce powder.

EXAMPLE 6

357 g of sodium bicarbonate was mixed with 200 mi of water to produce a homogeneous solution, 643 g of third Uquid sodium siUcate (SiO₂:Na₂O = 3.21:1) was mixed with 700 mi of water, and the resulting solutions reacted with each other in a reactor at 125 ^°C for 1 - 2 hours to produce slurry containing 50 - 70 % of water. The slurry was dried to produce powder.

EXAMPLE 7 332 g of sodium bicarbonate was mixed with 200 mi of water to produce a homogeneous solution, 668 g of fourth Uquid sodium siUcate (SiO :Na₂O = 3.76:1) was mixed with 700 ni-€. of water, and the resulting solutions reacted with each other in a reactor at 125 ^°C for 1.5 hours to produce slurry containing 50 - 70 % of water. The slurry was dried to produce powder. EXPERIMENTAL EXAMPLE 1

It was confirmed that powders produced according to examples 1 to 7 contained about 65 - 95 % of sodium sesquicarbonate and about 5 - 35 % of layered siUcate.

Production of a detergent composition Detergent compositions were produced using components as described in the foUowing Table 1.

TABLE 1

EXPERIMENTAL EXAMPLE 2

Detergency of the detergent composition was evaluated using the foUowing devices under the foUowing conditions. Washing device : Terg-o-tometer Washing temperature : 20 ^°C Washing water : hardness Ca²⁺ 80 ppm Mg²⁺ 20 ppm Bath ratio : 4.3 g C (stained fabric / washing water) Stained fabric: CFT AS-9 (pigment/oU) Concentration of the detergent : 0.67 g E Evaluation : converted with the proviso that a value of comparative example 1 is 100

Test results are described in the foUowing Table 2.

TABLE 2

Industrial AppUcabiUty

As described above, the present invention provides an environmentaUy friendly and nonpoUuting detergent composition, which includes powder consisting of sodium sesquicarbonate and layered siUcate, and has detergency that is the same as or superior to a conventional detergent even though it contains a minimum amount of surfactant

Claims

1. A laundry detergent composition, comprising: 75 - 90 wt% (hereinafter, a total weight of the laundry detergent composition is set as a basis) of powder including sodium sesquicarbonate and layered siUcate mixed with each other in a weight ratio of65:35-95:5; 5- 10 wt% of surfactant; and 0-20 wt% of additive typicaUy appUed to a laundry detergent.

2. The laundry detergent composition as set forth in claim 1, wherein the powder including sodium sesquicarbonate and layered siUcate is produced through a method which comprises (a) mixing a sodium siUcate aqueous solution with a separately prepared sodium bicarbonate aqueous solution to produce a reaction solution, (b) heating the reaction solution to form slurry, and (c) drying the slurry to produce the powder.

3. The laundry detergent composition as set forth in claim 1, wherein the powder including sodium sesquicarbonate and layered silicate is produced through a method which comprises (a) mixing sodium siUcate, sodium bicarbonate, and water with each other to produce a reaction solution, (b) heating the reaction solution to form slurry, and (c) drying the slurry to produce, the powder.

4. The laundry detergent composition as set forth in claim 2 or 3, wherein a ratio of SiO :Na₂O of sodium siUcate in the step of (a) is 2.1 : 1 - 3.8: 1.

5. The laundry detergent composition as set forth in claim 2 or 3, wherein the step of (b) is conducted at 100 - 150 ^°C.

6. The laundry detergent composition as set forth in claim 2 or 3, wherein the sluny contains - 70 % of water in the step of (b).