EP0889116A1

EP0889116A1 - High-density granular detergent composition

Info

Publication number: EP0889116A1
Application number: EP97907351A
Authority: EP
Inventors: Shu Kao Corporation YAMAGUCHI; Shigeru Kao Corporation TAMURA; Masaki Kao Corporation TSUMADORI; Hiroyuki Kao Corporation YAMASHITA
Original assignee: Kao Corp
Current assignee: Kao Corp
Priority date: 1996-03-19
Filing date: 1997-03-17
Publication date: 1999-01-07
Anticipated expiration: 2017-03-17
Also published as: DE69729287D1; JP3187437B2; EP0889116A4; ID16280A; DE69729287T2; TW403781B; EP0889116B1; WO1997034978A1

Abstract

A high-density granular detergent composition including A) one or more surfactants; B) one or more crystalline alkali metal silicates having an SiO₂/Na₂O molar ratio of from 0.5 to 2.6; and C) one or more metal ion capturing agents other than Component B, having a calcium ion capturing ability of 200 CaCO₃ mg/g or more. Here, a total amount of Component A, Component B, and Component C is from 70 to 100% by weight of the entire granular detergent composition, and a weight ratio of Component B to Component A is B/A = 9/1 to 9/11, and a weight ratio of Component B to Component C is B/C = 4/1 to 1/15. The high-density granular detergent composition includes granules (I) containing the crystalline alkali metal silicate of Component B and granules (II) containing the metal ion capturing agents of Component C, the granules (I) and the granules (II) being present substantially in separate granules.

Description

TECHNICAL FIELD

The present invention relates to a phosphorus-free, high-density granular detergent composition. More specifically, the present invention relates to a high-density granular detergent composition exhibiting excellent detergency even when a small amount of dosage is used.

BACKGROUND ART

Moreover, to date, various kinds of chelating agents, ion exchange materials, alkalizing agents, and dispersants have been known to be used for builders which are blended in detergents. Particularly, the phosphoric acid-based chelating agents comprising tripolyphosphates as a main component thereof have good water solubility and detergency, so that they have been formulated as main detergent builder ingredients.

In recent years, however, the use of tripolyphosphates has been decreased, since they are liable to cause eutrophication in closed water areas such as lakes and marshes. Instead, crystalline aluminosilicates (zeolites), which are synthetic ion exchange materials, have been used as substitutes for the metal ion capturing agent. Many patent applications concerning the formulation of the synthetic crystalline aluminosilicates in detergents, as typically disclosed in Japanese Patent Laid-Open No. 50-12381, of which the disclosure is incorporated herein by reference. In addition, Yushi (Vol, 32, No.1, pp.36-40 (Jan. 1979)), of which the disclosure is incorporated herein by reference, discloses the substitution to zeolites which took place at that time.

The rapid progress has taken place in changes in use of phosphorus-free detergents by substituting with zeolites, but the formulation of zeolites is merely a substitution of phosphorus-containing builders, which are used to produce detergents with a low bulk density of 0.2 to 0.4 g/cm³. Such detergents would require a standard amount of dosage of 40 g and 100 to 200 cm³ per one washing cycle, the washing cycle being most commonly using about 30 L of the washing liquid per one cycle in Japan. Therefore, in the case where detergents for 60 to 100 washing cycles are placed in a carton package, the resulting detergent package becomes undesirably heavy as from 2.5 to 4.5 kg and undesirably bulky as from 6000 to 20000 cc. Therefore, much inconveniences were caused in burdening the conveying costs in the plant and carrying inconveniences and storage space for the consumers.

Therefore, intense studies have been made to produce compact detergents. For instance, Japanese Patent Laid-Open Nos. 62-167396, 62-167399, and 62-253699, of which the disclosure is incorporated herein by reference, disclose a remarkable decrease in the amount of crystalline inorganic salts such as sodium sulfate used as powdering aids conventionally contained in detergents. In addition, Japanese Patent Laid-Open Nos. 61-69897, 61-69899, 61-69900, and 5-209200, of which the disclosure is incorporated herein by reference, disclose that an increase in the bulk density of the detergents. By these findings, detergents having a bulk density of from 0.60 to 1.00 g/ml, whose standard amount of dosage is from 25 to 30 g/30 L, can be produced, thereby resulting in making the detergents compact to a level of a standard volumetric amount of from 25 to 50 ml/30 L.

However, in conventional detergents, a large amount of surfactants had to be blended in the detergent compositions because mainstream of the technical idea was to make the oily components in dirt soluble by surfactants. Specifically, sebum dirt stains ascribed to human bodies, the most typical dirt stains adhered to clothes (most likely to be observed on collars and sleeves), are taken as examples. The sebum dirt stains contains oily components, such as free fatty acids and glycerides, with a high content of 70% or more (Ichiro KASHIWA et al., "Yukagaku," 19, 1095 (1969)), of which the disclosure is incorporated herein by reference. The oily components lock carbon and dirt in dust and peeled keratin, so that the resulting substance is observed as dirt stains. In order to wash off the sebum dirt stains, conventionally detergents are designed based on a washing mechanism mainly by making these oily components soluble with micelle of surfactants, thereby detaching carbon, dirt, and keratin from clothes. This technical idea has been widely established among those of ordinary skill in the art, and even when the conventional detergents are shifted to compact detergents, substantially no changes took place in the surfactant concentration in the washing liquid. This fact is described in "Dictionary for Detergents and Washing," Haruhiko OKUYAMA et al., p. 428, 1990, First Edition, Asakura Publishing Company Limited, of which the disclosure is incorporated herein by reference, which shows that there are substantially no changes in concentrations in the washing liquid for components other than sodium sulfate.

Based on these washing principles, the surfactant concentration in the washing liquid has to be made high in order to achieve high washing power, so that a large amount of surfactants has to be blended in the detergent composition. Therefore, a drastic reduction in the standard amount of dosage of the detergents was actually difficult. In addition, the presently known production method substantially enables to increase the bulk density to a level of about at most 1.00 g/ml. Therefore, a further reduction in the standard volumetric amount was deemed to be technically extremely difficult problem.

On the other hand, crystalline alkali metal silicates having particular structure disclosed in Japanese Patent Laid-Open Nos. 5-184946 and 60-227895, of which the disclosure is incorporated herein by reference, shows not only good ion exchange capacity but also actions of alkalizing agents (alkalizing ability). Therefore, possibility of more compact detergents has been studied because both of the functions which conventionally have been satisfied by two different components, including metal ion capturing agents, such as zeolites, and alkalizing agents, such as sodium carbonate, can be satisfied with the above crystalline alkali metal silicates alone.

For instance, Japanese Patent Laid-Open No. 6-116588, of which the disclosure is incorporated herein by reference, is concerned with a detergent composition containing a crystalline alkali metal silicate. In Examples of this publication disclosing a more compact detergent, even in a case where the amount of the detergent composition at washing is reduced by 25% by weight, the detergent composition has a washing power substantially the same as conventional detergent compositions. However, the composition has a high surfactant concentration. Therefore, the ion exchange capacity are ascribed solely to the crystalline alkali metal silicates contained therein, so that the ion exchange capacity is insufficient for that needed for detergent compositions. In this case, the functions of the crystalline alkali metal silicates as alkalizing agents are prioritized over their functions as metal ion capturing agents, and the function as the metal ion capturing agent is not sufficiently exhibited, so that the washing power of the detergent composition is not always satisfactory. Therefore, if the amount of dosage of the detergent composition were reduced, a good washing power is not able to be maintained.

A number of patent applications have been filed concerning the crystalline silicates disclosed in Japanese Patent Laid-Open No. 60-227895, of which the disclosure is incorporated herein by reference. Japanese Patent Unexamined Publication No. 6-502199, of which the disclosure is incorporated herein by reference, discloses a detergent comprising a layered crystalline silicate, a zeolite, and a polycarboxylate in particular proportions, to thereby provide a detergent which is free from providing film layer formation on fibers and has excellent washing power and bleaching agent stability. However, under the blending conditions given in this publication, when the amount of the detergents added was reduced at washing, the alkalizing ability is deficient because the amount of the crystalline alkali metal silicate in the builder composition is small, thereby making it impossible to maintain good washing power. Also, this publication never teaches the technical idea that an excellent washing power is exhibited in a small amount of dosage of detergents.

The technical idea that an excellent washing power is exhibited in a small amount of dosage of detergents as in the present invention cannot be found for detergents containing crystalline alkali metal silicates (crystalline layered silicates) disclosed in Japanese Patent Unexamined Publication 6-500141, Japanese Patent Laid-Open Nos 2-178398 and 2-178399, each of which the disclosure is incorporated herein by reference. Rather, in the case where the amounts of the detergent compositions shown in each of Examples are reduced, the washing power is lowered.

On the other hand, it is generally known that the addition of metal ion capturing agents, such as zeolites, to detergents reduces the effects of calcium ions and magnesium ions on surfactants, thereby removing dirts adhered to clothes, while the detergents inhibiting redeposition due to freed dirts by increasing dispersion of dirt stains by making the washing liquid alkaline.

Therefore, in general, conventional detergent granules include alkalizing agents and metal ion capturing agents. The detergent granules are generally produced by the following method.

Specifically, a slurry comprising aqueous dispersion of surfactants, mainly comprising anionic surfactants and nonionic surfactant; alkalizing agents, such as sodium carbonate and sodium silicates; calcium ion capturing agents (metal ion capturing agents), such as zeolites and sodium tripolyphosphate; fillers, such as sodium sulfate; and other components which are stable against heat is prepared. Thereafter, the resulting slurry is dried to be formed into granules. Subsequently, materials including perfumes which are unstable against heat, and in certain cases, bleaching agents and bleaching activators are post-blended, to give desired detergent granules.

Incidentally, phosphorus-based metal ion capturing agents typically exemplified by tripolyphosphates have been formulated in dry granules, the tripolyphosphates being generally employed as calcium ion capturing agents before the use of zeolites. This is because the phosphorus-based metal ion capturing agents have a function of alkalizing agents besides the calcium ion capturing capacity and also have most suitable properties for improving powder properties, such as flowability, of the dried granules.

In the detergent granules mentioned above, since the alkalizing agents, such as alkali metal carbonates and alkali metal silicates, also have characteristics of improving flowability by mechanically strengthening the granules themselves, the alkalizing agents act to form surfactants with plasticity and form zeolite fine particles into granules, so that the alkalizing agents are generally included in the same granules as the surfactants and the zeolites.

As mentioned above, since the metal ion capturing agents and the alkalizing agents are formulated in the same granules in the conventional detergents, the dissolution of these components may simultaneously show alkalizing ability and metal ion capturing capacity in the washing liquid. In certain cases, it can be thought that the alkalizing ability is exhibited earlier than the metal ion capturing capacity because a rate of reaction of the metal ion capturing agents with calcium ions and magnesium ions in water is delayed more than a rate of reaction of an alkalizing agent and water. The same can be said for liquid detergents, wherein the metal ion capturing agents and the alkalizing agents are mixed in the same liquid, the alkalizing ability and the metal ion capturing capacity may be simultaneously shown, or the alkalizing ability is shown earlier than the metal ion capturing capacity.

Incidentally, most man-derived sebum dirt stains contain fatty acids. During wash, calcium and magnesium ions together with fatty acids form a scum, thereby lowering dissolution and inhibiting the dispersion of the dirt stains in water. In particular, the present inventors have found that the scum-formation rate becomes faster as the alkalization degree (pH) becomes higher, and that washing performance cannot be optimally exhibited in conventional washing methods.

Aside from the ones mentioned above, several methods comprising dry-blending alkalizing agents as separate granules in the detergent granules have been conventionally known.

For instance,

(1) Japanese Patent Examined Publication No. 3-52798, of which the disclosure is incorporated herein by reference, discloses a method for producing detergent builders having a small bulk density comprising adding organic compounds, such as polyethylene glycols, to alkali metal carbonates and/or alkali metal sulfates; and granulating the resulting mixture. In this publication, the purpose is to improve the granular strength and the solubility, not to increase the detergency effects by making the dissolution of the alkalizing agents later than that of the metal ion capturing agents. Therefore, the alkalizing agent particles shown in Examples of the publication contain a small amount of a binder, and the polyethylene glycol has a low molecular weight, never teaching a delayed exertion of the alkalizing ability.

(2) Japanese Patent Laid-Open No. 55-52396, of which the disclosure is incorporated herein by reference, discloses a method of dry-blending particular alkali metal silicate particles to detergent granules containing surfactants and chelating agents, such as zeolites. In this publication, however, the purpose is to prevent the formation of water-insoluble materials owing to mutual interactions between silicates and zeolites and to maintain anti-corrosive effects on the washing machines, and is not to increase the detergency effects by making the dissolution of the alkalizing agents later than that of the chelating agents. Therefore, the silicate particles shown in Examples of this publication have a large particle size, but they are not intended to reduce the alkalizing ability by changing the particle sizes.

(3) Japanese Patent Laid-Open No. 62-167399, of which the disclosure is incorporated herein by reference, discloses a method for producing detergent granules having a high bulk density by limiting the amount of water-soluble, crystalline inorganic salts in the detergent base materials and dry-blending alkalizing agents with detergent granules in order to prevent the decrease in solubility of the detergent granules by increasing bulk densities thereof. However, for the same reasons set forth in (2) above, this publication does not suggest the increase in the detergency effects by making the dissolution of the alkalizing agents later than that of the metal ion capturing agent.

(4) Japanese Patent Laid-Open No. 58-213099, of which the disclosure is incorporated herein by reference, discloses a method for producing clothes detergents comprising dry-blending sodium carbonate with spray-dried powdery detergent base materials, the sodium carbonate having a particular density, particle size, and particle size distribution. The purposes of this publication, however, are to improve caking resistance and to prevent classification of sodium carbonate, and not to increase the detergency effects by making the dissolution of the alkalizing agents later than that of the metal ion capturing agents. Therefore, even in Examples of this publication, sodium silicate is included in the detergent base materials in relatively large amounts, the sodium silicates being incorporated in the same granules as zeolites, which are metal ion capturing agents.

Accordingly, there are no prior art references having the purpose of exhibiting an alkalizing ability to be delayed more than that of the metal ion capturing capacity. In the methods of post-blending alkalizing agents as described above, the alkalizing agents are blended simply for the following purposes: Since the zeolites are water-insoluble, the zeolites are added for preventing the zeolites to remain on fibers caused by the action of the silicates to suppress the dispersion of the zeolite in cases where the zeolites are blended with silicates in the form of fine particles. Also, the zeolites are added to improve caking resistance and solubility of the detergents. Moreover, in the conventional detergents mentioned above, since the alkalizing agents directly contact the washing liquid, the initiation of the alkalizing effect is faster than the case where the metal ion capturing agent and the surfactants are formulated in the same granules.

An object of the present invention is to provide a most effective high-detergent granular detergent composition for exhibiting excellent detergency even when the amount of dosage is small in the formulation composition comprising crystalline alkali metal silicates.

These and other objects of the present invention will be apparent from the following description.

DISCLOSURE OF THE INVENTION

As a result of intense studies in view of the above objects, the present inventors have found that since the granular detergent composition comprises particular blending ratios, wherein the granules containing the crystalline alkali metal silicates and granules containing the metal ion capturing agents are blended as separate granules, an optimum detergency can be obtained even when the amount of dosage is small. The present invention has been completed based on these findings.

The present invention is concerned with the following.

(1) A high-density granular detergent composition comprising:

A) one or more surfactants;

B) one or more crystalline alkali metal silicates having an SiO₂/Na₂O molar ratio of from 0.5 to 2.6; and

C) one or more metal ion capturing agents other than Component B, having a calcium ion capturing ability of 200 CaCO₃ mg/g or more,
wherein a total amount of Component A, Component B, and Component C is from 70 to 100% by weight of the entire granular detergent composition, wherein a weight ratio of Component B to Component A is B/A = 9/1 to 9/11, and wherein a weight ratio of Component B to Component C is B/C = 4/1 to 1/15,

wherein the high-density granular detergent composition comprises granules (I) containing the crystalline alkali metal silicate of Component B and granules (II) containing the metal ion capturing agents of Component C, the granules (I) and the granules (II) being present substantially in separate granules;

(2) The high-density granular detergent composition described in item (1), wherein the amount of the alkalizing agents other than the crystalline alkali metal silicates of Component B is 20% by weight or less in the entire granular detergent composition;

(3) The high-density granular detergent composition described in item (1) or item (2), wherein the content of sodium carbonate is 10% by weight or less in the entire granular detergent composition;

(4) The high-density granular detergent composition described in any one of items (1) to (3), wherein the granules (I) have an average particle size of from 300 to 1000 µm;

(5) The high-density granular detergent composition described in any one of items (1) to (4), wherein ingredients including Component B in the granules (I) are coated with binders comprising organic substances;

(6) The high-density granular detergent composition described in item (5), wherein the binders comprise nonionic surfactants, the nonionic surfactants being contained in an amount of 50% by weight or more of the binders;

(7) The high-density granular detergent composition described in item (5) or (6), wherein the binders are selected from:

1) one or more nonionic surfactants;

2) a mixture comprising one or more nonionic surfactants and one or more gel-formable anionic surfactants;

3) a mixture comprising one or more nonionic surfactants and one or more polyethylene glycols having weight-average molecular weights of 3000 or more; and

4) a mixture comprising one or more nonionic surfactants, one or more gel-formable anionic surfactants, and one or more polyethylene glycols having weight-average molecular weights of 3000 or more;

(8) The high-density granular detergent composition described in any one of items (1) to (7), wherein the crystalline alkali metal silicate of Component B is represented by the following formula (1): xM₂O·ySiO₂·zMe_mO·_nwH₂O, wherein M stands for an element in Group Ia of the Periodic Table; Me stands for one or more members selected from the group consisting of elements in Group IIa, IIb, IIIa, IVa, and VIII of the Periodic Table; y/x is 0.5 to 2.6; z/x is 0.01 to 1.0; n/m is 0.5 to 2.0; and w is 0 to 20; and

(9) The high-detergent granular detergent composition described in any one of items (1) to (7), wherein the crystalline alkali metal silicate of Component B is represented by the following formula (2): M₂O·x'SiO₂·y'H₂O, wherein M stands for an alkali metal atom; x' is 1.5 to 2.6; and y' is 0 to 20.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a graph of a calibration curve showing the relationship between the logarithm of the calcium ion concentration and the voltage; and

Figure 2 is a graph showing the relationships between the amount of the CaCl₂ aqueous solution added dropwise and the calcium ion concentration.

The reference numerals in Figure 2 are as follows:

A is an intersection of the extension of the linear portion of Line Q with the abscissa (horizontal axis); P shows the data of the blank solution (buffer solution without using the chelating agent); and Q shows the data for the chelating agent-containing buffer solution.

BEST MODE FOR CARRYING OUT THE INVENTION

The high-density granular detergent composition of the present invention comprises the following components:

A) one or more surfactants;

wherein the high-density granular detergent composition comprises granules (I) containing the crystalline alkali metal silicate of Component B and granules (II) containing the metal ion capturing agents of Component C, the granules (I) and the granules (II) being present substantially in separate granules.

In addition, the high-density granular detergent composition of the present invention preferably has a bulk density exceeding 0.5 g/cc, more preferably from 0.7 to 1.1 g/cc.

Each of the components will be explained in detail below.

A) Surfactants

The surfactants usable in the present invention are not particularly limited, and any ones generally used for detergents are used, in which the amount of a nonionic surfactant is preferably from 50 to 100% by weight, more preferably from 65 to 100% by weight, of the entire surfactant. Specifically, they may be one or more surfactants selected from the group consisting of nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants, each being exemplified below. For instance, the surfactants can be chosen such that the surfactants of the same kind are chosen, as in the case where a plurality of the nonionic surfactants are chosen. Alternatively, the surfactants of the different kinds can be chosen, as in the case where the anionic surfactant and the nonionic surfactant are respectively chosen. However, since soap surfactants do not contribute to detergency, their formulated amounts are not counted as the amounts of the surfactant components in the present invention.

Examples of the nonionic surfactants are as follows:

Polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitol fatty acid esters, polyoxyethylene fatty acid esters, polyoxyethylene fatty acid alkyl esters, polyoxyethylene polyoxypropylene alkyl ethers, polyoxyethylene castor oils, polyoxyethylene alkylamines, glycerol fatty acid esters, higher fatty acid alkanolamides, alkylglycosides, alkylglucosamides, and alkylamine oxides.

Among the nonionic surfactants, a particular preference is given to polyoxyethylene alkyl ethers which are ethylene oxide adducts of primary or secondary alcohols, whose alkyl moieties are linear or branched, each having 10 to 18 carbon atoms, and the average molar number of ethylene oxide is from 5 to 15. It is more desired that polyoxyethylene alkyl ethers which are ethylene oxide adducts of primary or secondary alcohols, whose alkyl moieties are linear or branched, each having 12 to 14 carbon atoms, and the average molar number of ethylene oxide is from 6 to 10.

Examples of the anionic surfactants include alkylbenzenesulfonates, alkyl or alkenyl ether sulfates, alkyl or alkenyl sulfates, α-olefinsulfonates, α-sulfofatty acid salts, α-sulfofatty acid ester salts, alkyl or alkenyl ether carboxylates, amino acid-type surfactants, and N-acyl amino acid-type surfactants, with a preference given to alkylbenzenesulfonates, alkyl or alkenyl ether sulfates, and alkyl or alkenyl sulfates.

Examples of the cationic surfactants include quaternary ammonium salts, such as alkyl trimethylamine salts. Examples of the amphoteric surfactants include carboxy-type and sulfobetaine-type amphoteric surfactants.

The surfactant content is preferably from 1 to 45% by weight in the entire detergent composition, and the surfactant content is particularly in the following ranges, depending on the types of water for washing used.

1) In the case where the water for washing having a water hardness of 2 to 6°DH, the surfactant content is particularly preferably from 15 to 30% by weight;

2) In the case where the water for washing having a water hardness of 6 to 10°DH, the surfactant content is particularly preferably from 8 to 25% by weight; and

3) In the case where the water for washing having a water hardness of 10 to 20°DH, the surfactant content is particularly preferably from 5 to 20% by weight.

The content is preferably not lower than the lower limit of the above range, from the aspect of obtaining sufficient detergency, and the content is preferably not higher than the upper limit of the above range, from the aspect of maintaining good proportions of the alkalizing agents and the metal ion capturing agents, thereby making it possible to achieve good detergency.

B) Crystalline Alkali Metal Silicates

In the present invention, the crystalline alkali metal silicates are suitably used. Crystalline and amorphous alkali metal silicates have been known as the alkali metal silicates, but the crystalline silicates are highly preferred owing to its good ion capturing ability as well as its good alkalizing ability, so that the standard amount of dosage of the detergent composition can be even further reduced. Therefore, crystalline alkali metal silicates are preferred.

The crystalline alkali metal silicates usable in the present invention include alkali metal silicates preferably having SiO₂/M₂O molar ratios of from 0.5 to 2.6, wherein M stands for an alkali metal atom. Also, the preferred ranges of the SiO₂/M₂O molar ratios are 1.5 to 2.2. The above molar ratio is preferably 0.5 or more from the aspect of obtaining good ion exchange capacity and hygroscopic property, and the molar ratio is preferably 2.6 or less from the aspect of obtaining good alkalizing ability. Incidentally, the crystalline alkali metal silicates used in patent publications discussed in BACKGROUND ART section of the present invention have SiO₂/Na₂O molar ratios (S/N ratio) of from 1.9 to 4.0. However, in the present invention, when the S/N ratios of the crystalline alkali metal silicates are 2.6 or less, the resulting detergents have good washing power with a remarkable reduction in the standard amount of dosage.

Among the crystalline alkali metal silicates usable in the present invention, a preference is given to those having the following compositions:

(1) xM₂O·ySiO₂·zMe_mO_n·wH₂O, wherein M stands for an element in Group Ia of the Periodic Table; Me stands for one or more members selected from the group consisting of elements in Groups IIa, IIb, IIIa, IVa, and VIII of the Periodic Table; y/x is from 0.5 to 2.6; z/x is from 0.01 to 1.0; n/m is from 0.5 to 2.0; and w is from 0 to 20.

(2) M₂O·x'SiO₂·y'H₂O, wherein M stands for an alkali metal atom; x' is from 1.5 to 2.6; and y' is from 0 to 20.

First, the crystalline alkali metal silicates having the composition (1) above will be detailed below.

In the general formula (1), M stands for an element selected from elements in Group Ia of the Periodic Table, wherein the Group Ia elements may be exemplified by Na, K, etc. The Group Ia elements may be used alone, or in combination of two or more kinds. For instance, such compounds as Na₂O and K₂O may be mixed to constitute an M₂O component.

Me stands for one or more members selected from the group consisting of elements in Group IIa, IIb, IIIa, IVa, and VIII of the Periodic Table, and examples thereof include Mg, Ca, Zn, Y, Ti, Zr, and Fe, which are not particularly limited to the above examples. Here, a preference is given to Mg and Ca from the viewpoint of resource stock and safety. In addition, these elements may be used alone, or in combination of two or more kinds. For instance, such compounds as MgO and CaO may be mixed to constitute an Me_mO_n component.

In addition, the crystalline alkali metal silicates in the present invention may be in the form of hydrates, wherein the amount of hydration (w) is usually in the range of from 0 to 20 moles of H₂O.

With respect to the general formula (1), y/x is preferably from 0.5 to 2.6, more preferably from 1.5 to 2.2. From the aspect of anti-solubility in water, y/x is preferably 0.5 or more. When the anti-solubility in water is insufficient, powder properties of the detergent composition, such as caking properties, solubility, etc. are drastically lowered. From the aspect of sufficiently functioning as alkalizing agent and ion exchange materials, y/x is preferably 2.6 or less.

With respect to z/x, it is preferably from 0.01 to 1.0, more preferably from 0.02 to 0.9, still more preferably from 0.02 to 0.5. From the aspect of the anti-solubility in water, z/x is preferably 0.01 or more, and from the aspect of sufficiently functioning as ion exchange materials, z/x is preferably 1.0 or less.

With respect to x, y and z, there are no limitations, as long as y/x and z/x have the above relationships. When xM₂O, for example, is x'Na₂O·x''K₂O as described above, x equals to x' + x''. The same can be said for z when zMe_mO_n comprises two or more components. Further, "n/m is from 0.5 to 2.0" indicates the number of oxygen ions coordinated to the above elements, which actually takes values selected from 0.5, 1.0, 1.5, and 2.0.

The crystalline alkali metal silicate having the composition (1) consists of three components, M₂O, SiO₂, and Me_mO_n. Materials which can be converted to each of these components, therefore, are indispensable for starting materials for producing the crystalline alkali metal silicates in the present invention. In the present invention, known compounds can be suitably used for starting materials for the crystalline alkali metal silicates without limitations. Examples of the M₂O component and the Me_mO_n component include simple or complex oxides, hydroxides and salts of respective elements; and minerals containing respective elements. Specifically, examples of the starting materials for the M₂O component include NaOH, KOH, Na₂CO₃, K₂CO₃, and Na₂SO₄. Examples of the starting materials for the Me_mO_n component include CaCO₃, MgCO₃, Ca(OH)₂, Mg(OH)₂, MgO, ZrO₂, and dolomite. Examples of the starting materials for the SiO₂ component include silica sand, kaolin, talc, fused silica, and sodium silicate.

The method of producing the crystalline alkali metal silicate having the composition (1) may be exemplified by blending these starting material components to provide a desired composition in x, y, and z for the crystalline alkali metal silicate, and baking the resulting mixture at a temperature in the range of preferably from 300° to 1500°C, more preferably from 500° to 1000°C, still more preferably from 600° to 900°C, to form crystals. In this case, the heating temperature is preferably 300°C or more in order to sufficiently complete the crystallization. When the crystallization is insufficient, it may result in poor anti-solubility in water of the resulting crystalline alkali metal silicate. The heating temperature is preferably 1500°C or less, so that the formation of coarse grains are likely to be prevented. When the coarse grains are formed, it may result in a decrease in the ion exchange capacity of the resulting crystalline alkali metal silicate. The heating time is preferably 0.1 to 24 hours. Such baking can be preferably carried out in a heating furnace such as an electric furnace or a gas furnace.

The crystalline alkali metal silicate in the present invention has an excellent alkalizing ability, to a level that its maximum pH value exceeds 11 at 25°C in a 0.1% by weight dispersion. Also, it has an excellent alkaline buffering ability to a level that it takes 10 ml or more of a 0.1 N HCl aqueous solution to lower its pH to 10 at 25°C in 100 ml of a 0.1% by weight dispersion. In addition, the crystalline alkali metal silicate particularly has an excellent alkaline buffering effects, showing remarkably superior alkaline buffering effects to those of sodium carbonate and potassium carbonate.

Moreover, the crystalline alkali metal silicate in the present invention preferably has an ion exchange capacity of 100 CaCO₃ mg/g or more, more preferably from 200 to 600 CaCO₃ mg/g. Therefore, the crystalline alkali metal silicate is one of the materials having ion capturing ability in the present invention.

The amount of Si dissolved in water is preferably 110 mg/g or less, when calculated as SiO₂, indicating that the crystalline alkali metal silicate is substantially insoluble in water. Here, the term "substantially insoluble in water" refers to those having an amount of Si dissolved, when calculated as SiO₂, of preferably less than 110 mg/g, measurement being taken when adding a 2 g sample 100 g of ion-exchanged water and stirring the mixture at 25°C for 30 minutes. In the present invention, the crystalline alkali metal silicate having an amount of Si dissolved in water of 100 mg/g or less are more preferred.

Since the crystalline alkali metal silicate in the present invention has not only good alkalizing ability and alkaline buffering effects but also good ion exchange capacity, good detergency can be obtained by adding suitable amounts of the crystalline alkali metal silicate.

In the present invention, the crystalline alkali metal silicate has an average particle size of preferably from 0.1 to 50 µm, more preferably from 1 to 35 µm, still more preferably from 5 to 25 µm. From the aspect of preventing the lowering of the ion exchange speed, the average particle size of the crystalline alkali metal silicate is preferably 50 µm or less. In addition, from the viewpoint of having an even smaller specific surface area, the average particle is preferably 0.1 µm or more. When the ion exchange speed is slowed down, the detergency is liable to be lowered, and when the specific surface area is increased, the hygroscopic property and the CO₂ absorption property are increased, which in turn makes it likely to cause drastic quality deterioration. Incidentally, the average particle size referred herein is a median diameter obtained from a particle size distribution.

The crystalline alkali metal silicate having the average particle size and the particle size distribution described above is prepared by pulverizing using pulverizing devices, such as vibration mills, hammer mills, ball-mills, and roller mills. For instance, the crystalline alkali metal silicate can be easily obtained by pulverizing the material with a vibrating mill "HB-O" (manufactured by Chuo Kakohki Co., Ltd.).

The content of the crystalline alkali metal silicate having the general formula (1) is preferably from 4 to 75% by weight in the entire composition, with a particular preference given to the following compositions depending upon the water hardness of the water for washing used.

1) In the case of using water for washing having a water hardness of from 2 to 6°DH, the content of the crystalline alkali metal silicate is preferably from 20 to 55% by weight in the entire composition;

2) In the case of using water for washing having a water hardness of from 6 to 10°DH, the content of the crystalline alkali metal silicate is preferably from 10 to 45% by weight in the entire composition; and

3) In the case of using water for washing having a water hardness of from 10 to 20°DH, the content of the crystalline alkali metal silicate is preferably from 5 to 30% by weight in the entire composition.

The content of the crystalline alkali metal silicate is preferably within the above range from the aspect of satisfying good detergency.

Next, the crystalline alkali metal silicates having the composition (2) above will detailed below.

These crystalline alkali metal silicates are represented by the general formula (2): M₂O·x'SiO₂·y'H₂O, wherein M stands for an alkali metal atom; x' is from 1.5 to 2.6; and y' is from 0 to 20. Among them, a preference is given to the crystalline alkali metal silicates having x' and y' in the general formula (2) such that each satisfies 1.7 ≤ x' ≤ 2.2 and y' = 0, and those having a cationic exchange capacity of preferably 100 CaCO₃ mg/g or more, more preferably from 200 to 400 CaCO₃ mg/g, are usable. The above crystalline alkali metal silicates are one of the materials having ion capturing ability in the present invention.

Since the crystalline alkali metal silicate in the present invention has not only good alkalizing ability and alkaline buffering capacity but also good ion exchange capacity, good detergency can be obtained by adding suitable amounts of the crystalline alkali metal silicate.

The content of the crystalline alkali metal silicate having the general formula (2) is preferably 4 to 75% by weight in the entire composition, with a particular preference given to the following compositions depending upon the water hardness of the water for washing used.

A method for producing the above crystalline alkali metal silicates is disclosed in Japanese Patent Laid-Open No. 60-227895, of which the disclosure is incorporated herein by reference. The crystalline alkali metal silicates may be generally produced by baking glassy amorphous sodium silicate at a temperature of from 200° to 1000°C. Details of the production method is disclosed in "Phys. Chem. Glasses, 7, pp.127-138 (1966), Z. Kristallogr., 129, pp.396-404(1969)," of which the disclosure is incorporated herein by reference. Also, the crystalline alkali metal silicates are commercially available in powdery or granular forms under a trade name "Na-SKS-6" (δ-Na₂Si₂O₅) (manufactured by Hoechst). Also, Japanese Patent Laid-Open No. 7-187655, of which the disclosures are incorporated herein by reference, discloses a crystalline alkali metal silicate containing not only sodium but also a particular amount of potassium.

In the present invention, as in the case for the crystalline alkali metal silicates having the composition (1), the crystalline alkali metal silicates having the composition (2) have an average particle size of preferably from 0.1 to 50 µm, more preferably from 1 to 35 µm, still more preferably from 5 to 25 µm.

In the present invention, the crystalline alkali metal silicates having the compositions (1) and (2) may be used alone or in combination. It is preferred that the crystalline alkali metal silicates occupy 50 to 100% by weight, more preferably from 70 to 100% by weight, of the total content of the alkalizing agents.

C) Metal Ion Capturing Agents Other Than Component B

The metal ion capturing agents of Component C in the present invention are preferably those having a calcium ion capturing capacity of 200 CaCO₃ mg/g or more, and any one of those conventionally formulated in detergent compositions other than Component B may be used.

In particular, an aluminosilicate having an ion exchange capacity of 200 CaCO₃ mg/g or more and having the following formula (3): x''(M₂O)·Al₂O₃·y''(SiO₂)·w''(H₂O), wherein M stands for an alkali metal atom, such as sodium or potassium atom; x'', y'', and w'' each stands for a molar number of each component; and generally, x'' is from 0.7 to 1.5; y'' is from 0.8 to 6.0; and w'' is from 0 to 20.

The aluminosilicates mentioned above may be crystalline or amorphous, and among the crystalline aluminosilicates, a particular preference is given to those having the following general formula: Na₂O·Al₂O₃·ySiO₂·wH₂O, wherein y is a number of from 1.8 to 3.0; and w is a number of from 1 to 6.

As for the crystalline aluminosilicates (zeolites), synthetic zeolites having an average, primary particle size of from 0.1 to 10 µm, which are typically exemplified by A-type zeolite, X-type zeolite, and P-type zeolite, are suitably used. The zeolites may be used in the forms of powder, a zeolite slurry, or dried particles comprising zeolite agglomerates obtained by drying the slurry. The zeolites of the above forms may also be used in combination.

The above crystalline aluminosilicates are obtainable by conventional methods. For instance, methods disclosed in Japanese Patent Laid-Open Nos. 50-12381 and 51-12805, of which the disclosure is incorporated herein by reference, may be employed.

On the other hand, the amorphous aluminosilicates represented by the same general formula as the above crystalline aluminosilicate are also obtainable by conventional methods. For instance, the amorphous aluminosilicates are prepared by adding an aqueous solution of a low-alkali alkali metal aluminate having a preferred molar ratio of M₂O to Al₂O₃ (M standing for an alkali metal) of M₂O/Al₂O₃ = 1.0 to 2.0 and a preferred molar ratio of H₂O to M₂O of H₂O/M₂O = 6.0 to 500 to an aqueous solution of an alkali metal silicate having a molar ratio of SiO₂ to M₂O of SiO₂/M₂O = 1.0 to 4.0 and a molar ratio of H₂O to M₂O of H₂O/M₂O = 12 to 200 under vigorous stirring at preferably 15° to 60°C, more preferably 30° to 50°C.

The intended product may be advantageously obtained by heat-treating a white slurry of precipitates thus formed preferably at 70° to 100°C, more preferably 90° to 100°C, for preferably 10 minutes or more and 10 hours or less, more preferably 5 hours or less, followed by filtration, washing and drying. Here, the addition method may comprise adding the aqueous solution of an alkali metal silicate to the aqueous solution of a low-alkali alkali metal aluminate.

By this method, the oil-absorbing amorphous aluminosilicate carrier having an ion exchange capacity of preferably 100 CaCO₃ mg/g or more and an oil-absorbing capacity of preferably 80 ml/100 g or more can be easily obtained (see Japanese Patent Laid-Open Nos. 62-191417 and 62-191419, of which the disclosure is incorporated herein by reference).

As Component C, a particular preference is given to the metal ion capturing agents containing a carboxylate polymer in an amount of 10% by weight or more. Examples of the above carboxylate polymer include polymers or copolymers, each having repeating units represented by the general formula (4):

wherein X₁ stands for a methyl group, a hydrogen atom, or a COOX₃ group; X₂ stands for a methyl group, a hydrogen atom, or a hydroxyl group; X₃ stands for a hydrogen atom, an alkali metal ion, an alkaline earth metal ion, an ammonium ion, or 2-hydroxyethylammonium ion.

In the general formula (4), examples of the alkali metal ions include Na, K, and Li ions, and examples of the alkaline earth metal ions include Ca and Mg ions.

Examples of the polymers or copolymers usable in the present invention include those obtainable by polymerization reactions of acrylic acid, (anhydrous) maleic acid, methacrylic acid, α-hydroxyacrylic acid, crotonic acid, isocrotonic acid, and salts thereof; copolymerization reactions of each of the monomers; or copolymerization reactions of the above monomers with other copolymerizable monomers. Here, examples of the other polymerizable monomers used in copolymerization reaction include aconitic acid, itaconic acid, citraconic acid, fumaric acid, vinyl phosphonic acid, sulfonated maleic acid, diisobutylene, styrene, methyl vinyl ether, ethylene, propylene, isobutylene, pentene, butadiene, isoprene, vinyl acetate (vinyl alcohols in cases where hydrolysis takes place after copolymerization), and acrylic ester, without particularly being limited thereto.

Also, polyacetal carboxylic acid polymers such as polyglyoxylic acids disclosed in Japanese Patent Laid-Open No. 54-52196, of which the disclosure is incorporated herein by reference, are also usable for the polymers in the present invention.

In the present invention, the above polymers and copolymers preferably have a weight-average molecular weight of from 800 to 1,000,000, more preferably from 5,000 to 200,000.

Also, in the case of copolymers, although the copolymerization ratios between the repeating units of the general formula (4) and other copolymerizable monomers are not particularly limited, a preference is given to copolymerization ratios of the repeating units of general formula (4)/other copolymerizable monomer = 1/100 to 90/10.

In the present invention, the above polymers or copolymers may be formulated in an amount of preferably from 1 to 50% by weight, more preferably 2 to 30% by weight, still more preferably from 5 to 15% by weight, in the entire composition.

Beside those mentioned above, examples of the other metal ion capturing agents of Component C include aminotri(methylenephosphonic acid), 1-hydroxyethylidene-1,1-diphosphonic acid, ethylenediaminetetra(methylenephosphonic acid), diethylenetriaminepenta(methylenephosphonic acid), and salts thereof; salts of phosphonocarboxylic acids, such as salts of 2-phosphonobutane-1,2-dicarboxylic acid; amino acid salts, such as aspartates and glutamates; polycarboxylates, such as citrates and tartrates; and aminopolyacetates, such as nitrilotriacetates and ethylenediaminetetraacetates.

In order to achieve excellent detergency with a small standard amount of dosage in the granular detergent composition of the present invention, the surfactants, the crystalline alkali metal silicate, and the metal ion capturing agents are needed to be formulated in particular compositional weight ratios. The crystalline alkali metal silicates are explained in detail above. In particular, the crystalline layered silicates disclosed in Japanese Patent Laid-Open No. 60-227895 shows good alkalizing ability as well as good ion exchange capacity. Therefore, it has been suggested to lower the standard amount of dosage by replacing the metal ion capturing agents, such as zeolites and polycarboxylates, and sodium carbonate and (amorphous) sodium silicate, the ingredients formulated in conventional detergent compositions, with a single component of the crystalline layered silicate. For instance, Japanese Patent Laid-Open No. 7-53992, of which the disclosure is incorporated herein by reference, discloses that the proportion of the detergent builders, including zeolites, substituted by the crystalline silicates is limited.

However, the present inventors have found that it would be difficult to achieve the objects of the present inventions by a mere substitution with the crystalline alkali metal silicate. In other words, the simple substitution with the crystalline alkali metal silicate would cause to drastically impair the compositional balance as a whole detergent, so that sufficiently good detergency cannot be obtained. Particularly in the present invention, the metal ion capturing agents other than the crystalline alkali metal silicate are essential ingredients, and the effects of the present invention cannot be obtained unless the other metal ion capturing agents are formulated in a particular compositional weight ratio to the crystalline alkali metal silicate in the granular detergent composition. In addition, the present inventors have found that the surfactant concentration in the washing liquid can be notably lowered when the crystalline alkali metal silicate and the other metal ion capturing agents are formulated in a particular compositional weight ratio in the detergent composition.

Specifically, a total amount of Component A, Component B, and Component C is from 70 to 100% by weight of the entire granular detergent composition, and the weight ratio of Component B to Component A is B/A = 9/1 to 9/11, and the weight ratio of Component B to Component C is B/C = 4/1 to 1/15. A particular preference is given to a case where a total amount of Component A, Component B, and Component C is from 80 to 100% by weight of the entire granular detergent composition, and the weight ratio of Component B to Component A is B/A = 9/1 to 1/1, and the weight ratio of Component B to Component C is B/C = 3/1 to 1/15. Most preferably, in the case where the water hardness of water for washing is from 2 to 6°DH, the weight ratio of Component B to Component C is B/C = 3/1 to 3/7; in the case where the water hardness is from 6 to 10°DH, the weight ratio of Component B to Component C is B/C = 4/3 to 1/6; and in the case where the water hardness is from 10 to 20°DH, the weight ratio of Component B to Component C is B/C = 1/1 to 1/15. In the present invention, by selecting the detergent composition depending upon the water hardness of the water for washing, the standard amount of dosage of the detergent composition can be further lowered.

In the present invention, besides the compositional weight ratio requirement mentioned above, when the granular detergent composition comprises granules (I) containing the crystalline alkali metal silicate of Component B and the granules (II) containing the metal ion capturing agents of Component C, the granules (I) and the granules (II) being present in substantially separate granules, the detergent composition exhibits the highest washing capability.

The amount of the alkalizing agents other than Component B included in the high-density granular detergent composition of the present invention is preferably 20% by weight or less, more preferably 10% or less, of the entire granular detergent composition. It is preferred that the crystalline alkali metal silicate of Component B is substantially present in the granules (I), and that the granules (I) are granulated products of the crystalline alkali metal silicate. The granulation is preferably carried out in a non-aqueous system, wherein organic substances and/or inorganic substance are preferably used as granulating agents (binders). Specifically, as a preferred embodiment, ingredients including Component B in the granules (I) are coated by binders comprising the organic substances. Examples of the organic substances usable for binders include nonionic surfactants in a solid state at room temperature, polyethylene glycols, and gel-formable anionic surfactants. Also, it is preferred that the binders made of the organic substances comprise nonionic surfactants, the nonionic surfactants being contained in an amount of preferably 50% by weight or more of the entire binders comprising organic substances. The amount of the nonionic surfactants is preferably 50% by weight or more from the aspect of having good detergency, thereby making it possible to wash items with a small standard amount of dosage without impairing its detergency.

The nonionic surfactants which may be usable for binders are not particularly limited, and any of conventionally known ones may be used. Examples thereof include polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitol fatty acid esters, polyoxyethylene fatty acid esters, alkyl polyoxyethylene fatty acid esters, polyoxyethylene polyoxypropylene alkyl ethers, polyoxyethylene castor oils, polyoxyethylene alkylamines, glycerol fatty acid esters, higher fatty acid alkanolamides, alkylglycosides, alkylglucosamides, and alkylamine oxides.

Among these nonionic surfactants, a preference is given to at least one member selected from polyoxyethylene alkyl ethers and polyoxyethylene alkylphenyl ethers, from the aspect of detergency.

The gel-formable anionic surfactants are not particularly limited, and any of conventionally known ones may be used. Examples thereof include alkali metal salts of saturated or unsaturated fatty acids, of which the alkyl moiety preferably has from 10 to 22 carbon atoms, more preferably from 12 to 18 carbon atoms; alkyl sulfates, of which the alkyl moiety preferably has from 10 to 22 carbon atoms, more preferably from 12 to 14 carbon atoms; salts of α-sulfonated fatty acids, of which the alkyl moiety preferably has from 10 to 22 carbon atoms, more preferably from 14 to 16 carbon atoms; and polyoxyethylene alkyl ether sulfates, of which the alkyl moiety has preferably from 10 to 22, and the average molar number of ethylene oxide moiety is from 0.2 to 2.0, and more preferably, polyoxyethylene alkyl ether sulfates, of which the alkyl moiety has preferably from 12 to 14, and the average molar number of ethylene oxide is from 0.5 to 1.5. In each of the above compounds listed above, it has preferably 10 or more carbon atoms from the viewpoints of detergency and odor, and it has preferably 22 or less carbon atoms from the viewpoints of detergency and solubility. The gel-formable anionic surfactants may be added in the form of acids, and then neutralized with the crystalline alkali metal silicate in a solid state.

The polyethylene glycols used herein include those having a weight-average molecular weight of preferably 3000 or more, more preferably from 3000 to 20000, still more preferably from 5000 to 13000.

Other binders usable in the present invention include at least one of saturated fatty acids and unsaturated fatty acids, of which the alkyl moiety has 12 to 20 carbon atoms. Besides them, polyvinyl alcohols, hydroxypropylmethyl cellulose, hydroxypropyl starches, and carboxymethyl cellulose having a low polymerization degree may be also included as binder ingredients. Also, metal soaps having a high water repellency, calcium carbonate, and silica powder may be also used therefor. Incidentally, in the case where a surfactant is used for a binder, it is considered as a part of a whole part of Component A.

The following are given as more preferred examples of binders.

1) one or more nonionic surfactants;

4) a mixture comprising one or more nonionic surfactants, one or more gel-formable anionic surfactants, and one or more polyethylene glycols having weight-average molecular weights of 3000 or more.

Here, particularly preferred examples include polyoxyethylene alkyl ethers and mixtures of the polyoxyethylene alkyl ethers and gel-formable anionic surfactants.

Incidentally, methods of granulating ingredients including the crystalline alkali metal silicate of Component B have already been known, as disclosed in Japanese Patent Unexamined Publication No. 6-502445, of which the disclosure is incorporated herein by reference. However, this prior art reference discloses an invention concerning a method for producing agglomerates of the crystalline alkali metal silicate, not concerned with a detergent composition with a small standard amount of dosage as in the present invention. In Examples of the publication, a composition comprising zeolite and a crystalline alkali metal silicate in separate granules is disclosed, but the granules comprise a zeolite-containing granule containing large amounts of sodium carbonate as an alkalizing agent, never suggesting the detergent composition of the present invention.

The binder is preferably added at a level needed for surface-coating such ingredients as the crystalline alkali metal silicate. By surface-coating such ingredients as the crystalline alkali metal silicate, the exhibition of the alkalizing ability in the washing liquid would be delayed, so that the scum formation rate in the sebum dirt stains which has been conventionally speeded up by the alkalis is slowed down, and that the metal ion capturing agents in the granules (II) can effectively function. As a result, the fatty acids in the sebum dirt stains act as soaps so as to aid the micelle formation of the dirt stains, thereby improving detergency. For the purpose of surface coating, the binder is added in the granules (I) in an amount of preferably from 10 to 80% by weight, more preferably from 30 to 70% by weight, depending upon the kinds of binders used.

As to the method for preparing the granules (I), there may be included a method for granulating an alkalizing agent by using a sufficient amount of an organic substance exemplified above as a binder. In addition, there may be included a method for coating an alkalizing agent with a coating agent in a fluidized bed, the coating agent being exemplified by polyvinyl alcohols, hydroxypropylmethyl cellulose, hydroxpropyl starches, and carboxymethyl cellulose having a low polymerization degree. Also, when the above granulation step or coating step is carried out, metal soaps having high water repellency, and hardly soluble calcium carbonate and silica powder may be also added.

Other ingredients which may be formulated in the granules (I) include optional ingredients which can be generally formulated in the detergent compositions exemplified below. For the purpose of improving powder properties, the aluminosilicates may be optionally formulated. In a case where a liquid nonionic surfactant is used, the amorphous aluminosilicates having good oil-absorbing capacity may be formulated to thereby reduce the bleed-out of the nonionic surfactants and improve anti-caking property. Also, the surfaces of the granules may be coated to thereby have good flowability of the powder. However, since the aluminosilicates also have an ion exchange capacity, it is preferred that a major portion of the aluminosilicates is not being present in the granules (I) except for those used for improving the powder properties.

The granules (I) preferably have an average particle size of from 300 to 1000 µm, with a preference to given those having a narrow particle size distribution with an even size as much as possible.

The granules (I) may be easily prepared by spraying binders to the powder starting materials in a mixer in which agitation, tumbling and mixing are usually carried out.

The granules (II) may comprise one or more metal ion capturing agents of Component C, such as aluminosilicates and polycarboxylates, without a binder, or the granules (II) may be granules prepared by using a binder. It is preferred that the granules (II) may be prepared by the following method: The metal ion capturing agents, such as aluminosilicates, polycarboxylates, and carboxylic polymers, anionic surfactants used as base surfactants, nonionic surfactants, such as salts of fatty acids and polyoxyethylene alkyl ethers, and inorganic substances, such as sodium sulfate, are added to prepare a slurry, the anionic surfactants being one or more members selected from alkylbenzenesulfonates, α-olefinsulfonates, alkyl sulfates, polyoxyalkylene alkyl ether sulfates, and methyl ester of α-sulfofatty acids. The resulting slurry is spray-dried and formed into powder to be used as the granules (II). More preferably, in order to increase the bulk density of the resulting granules (II), the spray-dried granules are further subjected to disintegration and granulation as disclosed in Japanese Patent Laid-Open Nos. 61-69897, 61-69898, and 61-69900, of which the disclosure is incorporated herein by reference. By utilizing the methods for increasing density, the granules (II) having excellent solubility can be obtained, thereby making it possible to allow the ion exchanging to take place prior to the action of the alkalizing agent.

Although it is preferred that the alkalizing agents are not included in the granules (II), for the purposes of easily carrying out the spray-drying process and of increasing mechanical strength of the granules, amorphous sodium silicates as defined in JIS may be formulated. However, in the present invention, substantially all of the alkalizing agents are preferably contained in the granules (I) mentioned above. Specifically, the crystalline alkali metal silicate contained in the granules (I) occupies preferably 60% by weight or more, more preferably 80% by weight or more, still more preferably 90% by weight or more, of the alkalizing agents in the entire high-density granular detergent composition.

In the present invention, the granules (I) may, for instance, comprise the following constituents: Crystalline alkali metal silicates of Component B, binders, aluminosilicates, the aluminosilicates being added in an amount sufficient for improving powder properties, and optionally other alkalizing agents and detergent additives, such as perfumes and fluorescent dyes. The granules (II) may, for instance, comprise anionic surfactants; aluminosilicates, such as zeolites; polycarboxylates and carboxylic polymers; inorganic salts, such as sodium sulfate; and optionally amorphous sodium silicates added as backbone substances and detergent additives, such as perfumes and fluorescent dyes. The majority of the alkalizing agents typically exemplified by the crystalline alkali metal silicates of Component B occupy the granules (I), but the metal ion capturing agents of Component C do not largely affect detergency when formulated in the granules (II). However, the most effective construction in the present invention is such that substantially all of the metal ion capturing agents other than Component B (namely Component C) are contained in the granules (II). Further, it is most effective when the granules (I) have such a construction that the alkalizing agents included therein are coated with a relatively large amount of the binders.

Although sodium carbonate may be used as an alkalizing agent, it is preferred that the sodium carbonate is contained in the granules (I) as described above. However, in a case where a large amount of sodium carbonate is formulated in the granules, it is likely to have water of crystallization by its hygroscopicity, which externally precipitates, thereby causing to lower the bulk density. Therefore, it is preferred that the content of sodium carbonate is 10% by weight or less, preferably 5% by weight or less, of the entire detergent composition.

Besides the above, the following ingredients may be also contained in the granular detergent composition of the present invention. For instance, enzymes, such as proteases, lipases, cellulases, and amylases; caking preventives, such as lower alkylbenzenesulfonates whose alkyl moieties have about 1 to 4 carbon atoms, sulfosuccinates, talc, and calcium silicates; and antioxidants, such as tert-butylhydroxytoluene and distyrenated cresol; bleaching agents, such as sodium percarbonate; bleaching activators, such as tetraacetyl ethylenediamine; fluorescent dyes; blueing agents; and perfumes may be included in the detergent composition. Of the above optional ingredients, enzymes, bleaching agents, and bleaching activators may be formed into separate third granules and blended in the detergent composition of the present invention. The optional ingredients are not particularly limited, and they may be blended so as to give desired compositions suitable for their purposes.

In addition, examples of the alkalizing agents included in the high-density detergent composition of the present invention other than Component B include sodium carbonate, sodium hydrogen carbonate, and a small amount of a sodium silicate such as JIS No. 1 or No. 2 so as not to lower the dissolution.

The tap water has water hardness greatly differing in various countries and geographical circumstances throughout the world. For instance, while the tap water has a water hardness of usually around 4°DH in Japan, the tap water having a water hardness of 6°DH or more in the U.S., and that exceeding 10°DH in European countries is used for the water for washing. Therefore, since the required absolute amount of the metal ion capturing agents varies, the standard detergent concentration would be optimally adjusted accordingly.

Specifically, in cases where the initial water hardness differs in each of the washing liquids, the detergent concentrations are as follows:

1) As for the water for washing having a water hardness of 2 to 6°DH, the detergent composition has a concentration in the washing liquid of from preferably 0.33 to 0.67 g/L, more preferably from 0.33 to 0.50 g/L.

2) As for the water for washing having a water hardness of 6 to 10°DH, the detergent composition has a concentration in the washing liquid of from preferably 0.50 to 1.20 g/L, more preferably from 0.50 to 1.00 g/L.

3) As for the water for washing having a water hardness of 10 to 20°DH, the detergent composition has a concentration in the washing liquid of from preferably 0.80 to 2.50 g/L, more preferably from 1.00 to 2.00 g/L.

Under these conditions, detergency equivalent or superior to that of the conventional detergents can be achieved in the high-density granular detergent composition for clothes washing of the present invention. Also, the DH water hardness is measured by an ion coupling plasma method (ICP method).

The present invention will be explained in further detail by means of the following working examples, without intending to restrict the scope of the present invention thereto.

The physical properties of products obtained in the working examples are measured by the following methods.

(1) Amount of Materials Having Ion Capturing Capacity

The ion capturing ability is measured by the following different methods in accordance with a case where the materials used having a metal ion capturing capacity are ion exchange materials and a case where the materials are chelating agents. Incidentally, the ion capturing capacity of the metal ion capturing agents are expressed by CEC (calcium ion exchange capacity) in Tables as in the same manner as in alkali metal silicates. In addition, the DH water hardness is measured by ion-coupling plasma method (ICP method).

Ion Exchange Material

The amount 0.1 g of an ion exchange material is accurately weighed and added to 100 ml of a calcium chloride aqueous solution (500 ppm concentration, when calculated as CaCO₃), followed by stirring at 25°C for 60 minutes. Thereafter, the mixture is filtered using a membrane filter (made of nitrocellulose; manufactured by Advantech) with 0.2 µm pore size. The amount 10 ml of the filtrate is assayed for Ca content by an EDTA titration, and the calcium ion exchange capacity (cationic exchange capacity) of the ion exchange material is calculated from the titer.

Chelating Agent

The calcium ion capturing capacity of the chelating agent is measured by the following method using a calcium ion electrode. Incidentally, the solution used herein is prepared with the following buffer solution:

Buffer:: 0.1 M-NH₄Cl-NH₄OH buffer (pH 10.0)

(i) Preparation of Calibration Curve

A standard calcium ion solution is prepared and voltage readings are taken to prepare a calibration curve showing the relationships between the logarithm of the calcium ion concentration and the voltage, as shown in Figure 1.

(ii) Measurement of Calcium Ion Capturing Capacity

About 0.1 g of a chelating agent is weighed, and a 100 ml volumetric flask is charged with the chelating agent. The volumetric flask is filled up to a volume of 100 ml with the above buffer solution. A CaCl₂ aqueous solution (pH 10.0) having a calcium ion concentration of 20,000 ppm calculated as CaCO₃ is added dropwise from a burette. The dropwise addition is made in an amount of 0.1 to 0.2 ml for each voltage reading. In addition, the buffer solution without containing the chelating agent is also subjected to the same dropwise treatment of the CaCl₂ aqueous solution. This solution is called a "blank solution." Thus, a calcium ion concentration is calculated from the calibration curve given in Figure 1 by taking a voltage reading. The relationship between the amount of the CaCl₂ aqueous solution added dropwise and the calcium ion concentration is shown in a graph (Figure 2). In Figure 2, Line P shows the data of the blank solution (buffer solution without using the chelating agent), and Line Q shows the data for the chelating agent-containing buffer solution. The point where the extension of the linear portion of Line Q intersects with the abscissa (horizontal axis) is called "A." The calcium ion capturing capacity of the chelating agent is obtained from the calcium ion concentration at "A" of the blank solution.

(2) Average Particle Size and Particle Size Distribution of Crystalline Alkali Metal Silicates

The average particle size and the particle size distribution are measured by using a laser scattering particle size distribution analyzer. Specifically, about 200 ml of ethanol is poured into a measurement cell of a laser scattering particle size distribution analyzer ("LA-700," manufactured by HORIBA Ltd.), and about 0.5 to 5 mg of the crystalline alkali metal silicate is suspended in ethanol. Next, while subjecting the obtained ethanol suspension to ultrasonic wave irradiation, the mixture is agitated for one minute, to thereby sufficiently disperse the crystalline alkali metal silicate. Thereafter, the resulting mixture is subjected to an He-Ne laser beam (632.8 nm) irradiation to measure diffraction/scattering patterns. The particle size distribution is obtained from the diffraction/scattering patterns. The analysis is made based on the combined theories of Fraunhofer diffraction theory and Mie scattering theory. The particle size distribution of the suspended particles in the liquid is measured within the size range of from 0.04 to 262 µm. The average particle size is a median diameter of the particle size distribution.

Preparation Example 1 (Crystalline Alkali Metal Silicate A)

To 1000 parts by weight of No. 2 sodium silicate (SiO₂/Na₂O = 2.5), 55.9 parts by weight of sodium hydroxide and 8.5 parts by weight of potassium hydroxide were added, followed by stirring using a homomixer to thereby dissolve sodium hydroxide and potassium hydroxide. To this solution, 5.23 parts by weight of finely dispersed anhydrous calcium carbonate and 0.13 parts by weight of magnesium nitrate hexahydrate were added, and the components were agitated by using a homomixer. A given amount of the mixture was transferred into a nickel crucible and baked in the air at a temperature of 700°C for one hour, followed by rapid cooling. The resulting baked product was powdered, to give Crystalline Alkali Metal Silicate A in the present invention. This powder had an ion capturing capacity as high as 305 CaCO₃ mg/g.

Preparation Example 2 (Amorphous Aluminosilicate)

Sodium carbonate was dissolved in ion-exchanged water, to prepare an aqueous solution with 6% by weight concentration. 132 g of the above aqueous solution and 38.28 g of a sodium aluminate aqueous solution (conc. 50% by weight) were placed in a 1000-ml reaction vessel equipped with baffles. 201.4 g of a solution of No. 3 liquid glass diluted with twice the amount of water were added dropwise to the above mixed solution by under vigorous agitation at a temperature of 40°C over a period of 20 minutes. Here, the reaction speed was optimized by adjusting the pH of the reaction system to 10.5 by blowing a CO₂ gas thereinto. Thereafter, the reaction system was heated up to a temperature of 50°C and stirred at 50°C for 30 minutes. Subsequently, an excess alkali was neutralized by blowing a CO₂ gas thereinto, and the pH of the reaction system was adjusted to 9.0. The obtained neutralized slurry was filtered under a reduced pressure using a filter paper (No. 5C, manufactured by Toyo Roshi Kaisha, Ltd.). The filtered cake was rinsed with water in an amount of 1000-folds that of the cake, and the rinsed cake was filtered and dried under the conditions of 105°C, 300 Torr, and 10 hours. Further, the dried cake was disintegrated, to give an amorphous aluminosilicate powder. Incidentally, the sodium aluminate aqueous solution was prepared by the steps of adding and mixing 243 g of Al(OH)₃ and 298.7 g of a 48% by weight NaOH aqueous solution in a 1000 ml four-necked flask, heating the mixture to a temperature of 110°C with stirring, and dissolving the components in 30 minutes to prepare a composition.

From the results of atomic absorption spectrophotometry and plasma emission spectrochemical analysis, the resulting amorphous aluminosilicate had the following composition: Al₂O₃ = 29.6% by weight; SiO₂ = 52.4% by weight; and Na₂O = 18.0% by weight (1.0 Na₂O · Al₂O₃ · 3.10 SiO₂). In addition, the calcium ion capturing capacity was 176 CaCO₃ mg/g, and the oil-absorbing capacity was 285 ml/100 g. The content of the microporous capacity having a microporous diameter of less than 0.1 µm was 9.4% by volume in the entire micropores, and the content of the microporous capacity having a microporous diameter of not less than 0.1 µm and not more than 2.0 µm was 76.3% by volume in the entire micropores. The water content was 11.2% by weight.

Example 1

33.0 parts by weight of Crystalline Alkali Metal Silicate (simply abbreviated as "Crystalline Silicate" in the tables) A prepared in Preparation Example 1 (average particle size: 8 µm) were supplied in a Lödige Mixer (Matsuzaka Giken Co., Ltd., equipped with a jacket), and the components were agitated while keeping the jacket temperature at 70°C. Subsequently, the above components were further subjected to granulation by blending in advance at 70°C to prepare a mixture comprising 10.0 parts by weight of a polyoxyethylene alkyl ether ("NONIDET R-7," manufactured by Mitsubishi Chemical Corporation, an alkylene oxide adduct, of which the alkyl moiety has 12 to 15 carbon atoms, and the ethylene oxide moiety has a molar number of 7.2) and 5.0 parts by weight of palmitic acid ("LUNAC P-95," manufactured by Kao Corporation), and spraying the resulting mixture to the above components while agitating. Here, a part or a whole part of the fatty acid was neutralized to form salts of the fatty acid on the surface of Crystalline Alkali Metal Silicate A having a high alkalizing ability, and thereby the surfaces of Crystalline Alkali Metal Silicate A were coated with gelated products comprising the polyoxyethylene alkyl ether and the salts of the fatty acid. Further, the resulting granules were surface-coated for improving the powder properties by adding 3.0 parts by weight of a zeolite (4A-type; average particle size: 3 µm, manufactured by Tosoh Corporation). The crystalline alkali metal silicate granules (hereinafter simply referred to as "crystalline silicate granules") (I) thus obtained had a bulk density of 0.89 g/cm³ and an average particle size of 452 µm.

17.0 parts by weight of a zeolite (4A-type; average particle size: 3 µm, manufactured by Tosoh Corporation), 5.0 parts by weight of an acrylic acid-maleic acid copolymer ("SOKALAN CP-5," manufactured by BASF; weight-average molecular weight: 70,000), 6.0 parts by weight of sodium sulfate, 1.0 part by weight of sodium sulfite, and 0.4 parts by weight of Fluorescent Dye B ("CINOPEARL CBS-X," manufactured by Ciba Geigy AG) were added to prepare an aqueous slurry of 50% by weight solid content. The resulting slurry was spray-dried using a countercurrent flow spray drier, to give spray-dried granules L having a water content of about 5% by weight of the dead weight. Thereafter, 30.5 parts by weight of the spray-dried granules L prepared above and 4.6 parts by weight of amorphous aluminosilicate prepared in Preparation Example 2 were supplied in a Lödige Mixer (Matsuzaka Giken Co., Ltd., equipped with a jacket) and stirred while keeping the jacket temperature at 70°C. Subsequently, the above components were further subjected to granulation by blending in advance at 70°C to prepare a mixture comprising 8.0 parts by weight of a polyoxyethylene alkyl ether ("NONIDET R-7," manufactured by Mitsubishi Chemical Corporation, an alkylene oxide adduct, of which the alkyl moiety has 12 to 15 carbon atoms, and the ethylene oxide moiety has a molar number of 7.2) and 1.0 part by weight of a polyethylene glycol ("KPEG," manufactured by Kao Corporation; weight-average molecular weight: 8000), and spraying the resulting mixture to the above components while agitating. Further, the granules were surface-coated for improving the powder properties by adding 3.0 parts by weight of the zeolite (4A-type). The metal ion capturing agent granules (I) thus obtained had a bulk density of 0.79 g/cm³ and an average particle size of 405 µm.

51.0 parts by weight of the crystalline silicate granules (I) prepared above, 47.5 parts by weight of the metal ion capturing agent granules (I) prepared above, 0.5 parts by weight of protease granules (granules of "ALKALI PROTEASE K-16" described in Japanese Patent Laid-Open No. 5-25492, of which the disclosure is incorporated herein by reference), 0.5 parts by weight of cellulase granules (granules of "ALKALI CELLULASE K" described in Japanese Patent Laid-Open No. 63-264699, of which the disclosure is incorporated herein by reference) and 0.3 parts by weight of lipase granules (granules of "LIPOLASE 100T," manufactured by NOVO Nordisk Bioindustry LTD.) were supplied in a V-type blender. While the components were agitated, 0.2 parts by weight of a perfume were sprayed to the granules for providing them with a fragrance, to give 100.0 parts by weight of the detergent composition of Inventive Product 1.

Comparative Example 1

30.5 parts by weight of the spray-dried granules L, 33.0 parts by weight of Crystalline Alkali Metal Silicate A prepared in Preparation Example 1, and 4.6 parts by weight of amorphous aluminosilicate prepared in Preparation Example 2 were supplied in a Lödige Mixer (Matsuzaka Giken Co., Ltd., equipped with a jacket), and the above components were agitated in the mixer at room temperature. The above components were further subjected to granulation by blending in advance at 70°C to prepare a mixture comprising 18.0 parts by weight of the polyoxyethylene alkyl ether ("NONIDET R-7"), 5.0 parts by weight of palmitic acid ("LUNAC P-95"), and 1.0 part by weight of the polyethylene glycol ("KPEG"), and spraying the resulting mixture to the above components while agitating. Further, the resulting granules were surface-coated for improving the powder properties by adding 6.0 parts by weight of the zeolite (4A-type). The comparative granules (I), which comprised a crystalline alkali metal silicate component and other metal ion capturing agents in one granule, thus obtained had a bulk density of 0.77 g/cm³ and an average particle size of 435 µm.

98.5 parts by weight of the comparative granules (I) prepared above, 0.5 parts by weight of the protease granules (granules of "ALKALI PROTEASE K-16" described in Japanese Patent Laid-Open No. 5-25492), 0.5 parts by weight of the cellulase granules (granules of "ALKALI CELLULASE K" described in Japanese Patent Laid-Open No. 63-264699), and 0.3 parts by weight of the lipase granules (granules of "LIPOLASE 100T") were supplied in a V-type blender. While the components were agitated, 0.2 parts by weight of a perfume were sprayed to the granules for providing them with a fragrance, to give 100.0 parts by weight of the detergent composition of Comparative Product 1 were obtained.

Example 2

30.5 parts by weight of Crystalline Alkali Metal Silicate A (average particle size: 8 µm) prepared in Preparation Example 1 were supplied in a Lödige Mixer (Matsuzaka Giken Co., Ltd., equipped with a jacket), and the contents were agitated while keeping the jacket temperature at 80°C. Thereafter, the contents were further subjected to granulation by blending in advance at 70°C to prepare a mixture comprising 11.0 parts by weight of a polyoxyethylene alkyl ether (tradename: "EMULGEN 108," manufactured by Kao Corporation, of which an ethylene oxide moiety has an average molar number of 6.0 and an alkyl moiety has 12 carbon atoms), 2.5 parts by weight of semi-cured beef tallow-derived fatty acid ("LUNAC TH," manufactured by Kao Corporation), and 2.5 parts by weight of a polyethylene glycol (manufactured by Kao Corporation; weight-average molecular weight: 10000), and spraying the resulting mixture to the above contents in the mixer while agitating. Here, a part or a whole part of the fatty acid was neutralized to form salts of the fatty acid on the surface of Crystalline Alkali Metal Silicate A having a high alkalizing ability, and thereby the surfaces of Crystalline Alkali Metal Silicate A were coated with gelated products comprising the polyoxyethylene alkyl ether, the salts of the fatty acid, and the polyethylene glycol. Further, the resulting granules were surface-coated for improving the powder properties by adding 3.0 parts by weight of a zeolite (4A-type, manufactured by Tosoh Corporation; average particle size: 3 µm). The crystalline silicate granules (II) thus obtained had a bulk density of 0.87 g/cm³ and an average particle size of 468 µm.

10.0 parts by weight of a sodium linear alkylbenzenesulfonate of which alkyl moiety has 12 carbon atoms, 2.0 parts by weight of a sodium alkylsulfate of which alkyl moiety has 14 carbon atoms, 2.0 parts by weight of the acrylic acid-maleic acid copolymer ("SOKALAN CP-5"), 1.0 part by weight of a sodium polyacrylate (weight-average molecular weight: 10,000), 17.0 parts by weight of the zeolite (4A-type), 2.0 parts by weight of sodium citrate (manufactured by Iwata Kagaku K.K.), 3.0 parts by weight of JIS No. 1 sodium silicate, 5.0 parts by weight of sodium sulfate, 1.0 part by weight of sodium sulfite, and 0.3 parts by weight of Fluorescent Dye S ("WHITEX SA," manufactured by Sumitomo Chemical Co., Ltd.) were added to prepare an aqueous slurry of 50% by weight solid content. The resulting slurry was spray-dried using a countercurrent flow spray drier to give spray-dried granules M having a water content of about 6% by weight of the dead weight. Thereafter, 46.0 parts by weight of the spray-dried granules M were supplied in a High-Speed Mixer (manufactured by Fukae Powtec Corp.) and granulated. Further, the granules were surface-coated for improving the powder properties by adding 3.0 parts by weight of the zeolite (4A-type). The metal ion capturing agent granules (II) thus obtained had a bulk density of 0.75 g/cm³ and an average particle size of 426 µm.

49.5 parts by weight of the crystalline silicate granules (II) prepared above, 49.0 parts by weight of the metal ion capturing agent granules (II) prepared above, 0.5 parts by weight of the protease granules (granules of "ALKALI PROTEASE K-16" described in Japanese Patent Laid-Open No. 5-25492), 0.5 parts by weight of the cellulase granules (granules of "ALKALI CELLULASE K" described in Japanese Patent Laid-Open No. 63-264699), and 0.3 parts by weight of the lipase granules (granules of "LIPOLASE 100T") were supplied in a V-type blender. While the components were agitated, 0.2 parts by weight of a perfume were sprayed to the granules for providing them with a fragrance, to give 100.0 parts by weight of the detergent composition of Inventive Product 2.

Comparative Example 2

46.0 parts by weight of the spray-dried granules M and 30.5 parts by weight of Crystalline Alkali Metal Silicate A prepared in Preparation Example 1 were supplied in a Lödige Mixer (Matsuzaka Giken Co., Ltd., equipped with a jacket), and the above components were agitated in the mixer at room temperature. Subsequently, the above components were further subjected to granulation by blending in advance at 80°C to prepare a mixture comprising 11.0 parts by weight of the polyoxyethylene alkyl ether ("EMULGEN 108"), 2.5 parts by weight of semi-cured beef tallow-derived fatty acid ("LUNAC TH"), and 2.5 parts by weight of the polyethylene glycol (weight-average molecular weight: 10000), and spraying the resulting mixture to the above components while agitating. Further, the resulting granules were surface-coated for improving the powder properties by adding 6.0 parts by weight of the zeolite (4A-type). The comparative granules (II), which comprised a crystalline alkali metal silicate and other metal ion capturing agents in one granule, thus obtained had a bulk density of 0.80 g/cm³ and an average particle size of 430 µm.

98.5 parts by weight of the comparative granules (II) prepared above, 0.5 parts by weight of the protease granules (granules of "ALKALI PROTEASE K-16" described in Japanese Patent Laid-Open No. 5-25492), 0.5 parts by weight of the cellulase granules (granules of "ALKALI CELLULASE K" described in Japanese Patent Laid-Open No. 63-264699), and 0.3 parts by weight of the lipase granules (granules of "LIPOLASE 100T") were supplied in a V-type blender. While the components were agitated, 0.2 parts by weight of a perfume were sprayed to the granules for providing them with a fragrance, to give 100.0 parts by weight of the detergent composition of Comparative Product 2 were obtained.

Example 3

25.0 parts by weight of Crystalline Alkali Metal Silicate B (δ-Na₂O·2SiO₂, prepared by pulverizing SKS-6™ powder product using a hammer mill to an average particle size of 23 µm; SKS-6: average particle size: 23 µm, 248 CaCO₃ mg/g), 6.0 parts by weight of amorphous aluminosilicate prepared in Preparation Example 2, and 0.2 parts by weight of Fluorescent Dye S were supplied in a Lödige Mixer (Matsuzaka Giken Co., Ltd., equipped with a jacket), and the above components were agitated while keeping the jacket temperature at 70°C. Thereafter, the above components were further subjected to granulation by blending in advance at 70°C to prepare a mixture comprising 10.0 parts by weight of a polyoxyethylene alkyl ether ("SOFTANOL 70," manufactured by Nippon Shokubai Co., Ltd., of which the alkyl moiety has an average number of 12.7 carbon atoms and the ethylene oxide moiety has an average addition number of 7.0) and 4.0 parts by weight of a polyethylene glycol (manufactured by Kao Corporation; weight-average molecular weight: 10000), and spraying the resulting mixture to the above components while agitating. Here, the surfaces of Crystalline Alkali Metal Silicate B were coated with the gelated products comprising the polyoxyethylene alkyl ether and the polyethylene glycol. Further, the resulting granules were surface-coated for improving the powder properties by adding 3.0 parts by weight of the zeolite (4A-type). The crystalline silicate granules (III) thus obtained had a bulk density of 0.85 g/cm³ and an average particle size of 465 µm.

5.0 parts by weight of a sodium linear alkylbenzenesulfonate of which alkyl moiety has 12 carbon atoms, 8.0 parts by weight of a sodium alkylsulfate of which alkyl moiety has 14 carbon atoms, 3.0 parts by weight of the acrylic acid-maleic acid copolymer ("SOKALAN CP-5"), 16.0 parts by weight of the zeolite (4A-type), 1.5 parts by weight of sodium carbonate, 2.5 parts by weight of JIS No. 1 sodium silicate, 6.0 parts by weight of sodium sulfate, 1.0 part by weight of sodium sulfite, and 0.3 parts by weight of Fluorescent Dye T were added to prepare an aqueous slurry of 50% by weight solid content. The resulting slurry was spray-dried using a countercurrent flow spray drier to give spray-dried granules N having a water content of about 6% by weight of the dead weight. Thereafter, 46.1 parts by weight of the spray-dried granules N were supplied in a High-Speed Mixer (manufactured by Fukae Powtec Corp.), and the contents were agitated and granulated, while 1.2 parts by weight of polyoxyethylene alkyl ether ("SOFTANOL 70") which was previously heated at 70°C as mentioned above was being added thereto. Further, the resulting granules were surface-coated for improving the powder properties by adding 3.0 parts by weight of the zeolite (4A-type). The metal ion capturing agent granules (III) thus obtained had a bulk density of 0.74 g/cm³ and an average particle size of 407 µm.

48.2 parts by weight of the crystalline silicate granules (III), 50.3 parts by weight of the metal ion capturing agent granules (III), 0.9 parts by weight of the protease granules (granules of "ALKALI PROTEASE K-16" described in Japanese Patent Laid-Open No. 5-25492), 0.2 parts by weight of the cellulase granules (granules of "ALKALI CELLULASE K" described in Japanese Patent Laid-Open No. 63-264699) and 0.2 parts by weight of the lipase granules (granules of "LIPOLASE 100T") were supplied in a V-type blender. While the components were agitated, 0.2 parts by weight of a perfume were sprayed to the granules for providing them with a fragrance, to give 100.0 parts by weight of the detergent composition of Inventive Product 3.

Comparative Example 3

46.1 parts by weight of the spray-dried granules N, 25.0 parts by weight of Crystalline Alkali Metal Silicate B, 6.0 parts by weight of amorphous aluminosilicate prepared in Preparation Example 2, and 0.2 parts by weight of Fluorescent Dye S were supplied in a Lödige Mixer (Matsuzaka Giken Co., Ltd., equipped with a jacket), and the components were agitated at room temperature. Subsequently, the components were further subjected to granulation by blending in advance at 70°C to prepare a mixture comprising 11.2 parts by weight of the polyoxyethylene alkyl ether ("SOFTANOL 70") and 4.0 parts by weight of the polyethylene glycol (weight-average molecular weight: 10000), and spraying the resulting mixture to the above components in the mixer while agitating. Further, the resulting granules were surface-coated for improving the powder properties by adding 6.0 parts by weight of the zeolite (4A-type). The comparative granules (III), which comprised a crystalline alkali metal silicate and other metal ion capturing agents in one granule, thus obtained had a bulk density of 0.81 g/cm³ and an average particle size of 410 µm.

98.5 parts by weight of the comparative granules (III) prepared above, 0.9 parts by weight of the protease granules (granules of "ALKALI PROTEASE K-16" described in Japanese Patent Laid-Open No. 5-25492), 0.2 parts by weight of the cellulase granules (granules of "ALKALI CELLULASE K" described in Japanese Patent Laid-Open No. 63-264699), and 0.2 parts by weight of the lipase granules (granules of "LIPOLASE 100T") were supplied in a V-type blender. While the components were agitated, 0.2 parts by weight of a perfume were sprayed to the granules for providing them with a fragrance, to give 100.0 parts by weight of the detergent composition of Comparative Product 3.

Test Example

Detergent Compositions obtained in Examples and Comparative Examples mentioned above were used to carry out a detergency test under the following conditions:

Preparation of Artificially Stained Cloth

An artificial staining liquid having the following compositions is adhered to a cloth (#2003 calico, manufactured by Tanigashira Shoten) to prepare an artificially stained cloth. Artificial staining liquid is printed on a cloth by an engravure staining machine equipped with an engravure roll coater. The process for adhering the artificial staining liquid to a cloth to prepare an artificially stained cloth is carried out under the conditions of a cell capacity of a gravure roll of 58 cm³/cm², a coating speed of 1.0 m/min, a drying temperature of 100°C, and a drying time of one minute.

Composition of Artificial Staining Liquid
Lauric acid	0.44% by weight
Myristic acid	3.09% by weight
Pentadecanoic acid	2.31% by weight
Palmitic acid	6.18% by weight
Heptadecanoic acid	0.44% by weight
Stearic acid	1.57% by weight
Oleic acid	7.75% by weight
Triolein	13.06% by weight
n-Hexadecyl palmitate	2.18% by weight
Squalene	6.53% by weight
Egg white lecithin crystalline liquid	1.94% by weight
Kanuma sekigyoku soil	8.11% by weight
Carbon black	0.01% by weight
Tap water	Balance

Washing Conditions

Washing of the above-mentioned artificially stained cloth in 4°DH water (Ca/Mg = 3/1) is carried out by using turgometer at a rotational speed of 100 rpm, at a temperature of 20°C for 10 minutes, in which washing is carried out at a detergent concentration of 0.5 g/L. Incidentally, the typical water hardness components in the water for washing are Ca²⁺ and Mg²⁺, whose weight ratios are generally in the range of Ca/Mg = (60-85)/(40-15). Here, a model sample of water of Ca/Mg = 3/1 is used. The unit "°DH" refers to a water hardness which is calculated by replacing Mg ions with equimolar amounts of Ca ions.

Calculation of Detergency Rate

Reflectivities of the original cloth and those of the stained cloth before and after washing were measured at 550 nm by means of an automatic recording colorimeter (manufactured by Shimadzu Corporation), and the detergency rate D (%) was calculated by the following equation. D = (L2 - L1)(L0 - L1) × 100(%), wherein

L₀: Reflectivity of the original cloth;

L₁: Reflectivity of the stained cloth before washing; and

L₂: Reflectivity of the stained cloth after washing.

The compositions and detergency rates of the detergent compositions are listed in Tables 1 to 3.

Incidentally, in the present specification, the calcium ion capturing capacity of the metal ion capturing agents other than Component B are as follows:

Zeolite (4A-type): 280 CaCO₃ mg/g.

Acrylic acid-maleic acid copolymer: 380 CaCO₃ mg/g.

Sodium polyacrylate: 220 CaCO₃ mg/g.

Sodium citrate: 310 CaCO₃ mg/g.

(Parts by Weight)
	Example 1	Comparative Example 1
	Crystalline Silicate Granule I	Metal Ion Capturing Agent Granule I
A)	Polyoxyethylene alkyl ether	10.0	8.0	18.0
Sodium alkylbenzenesulfonate			0.0
Sodium alkyl (C=14) sulfate			0.0
Palmitic acid	5.0		5.0
Semi-Cured Tallow Fatty Acid			0.0
B)	Crystalline Silicate A	33.0		33.0
Crystalline Silicate B			0.0
C)	4A-Type Zeolite	3.0	20.0	23.0
Acrylic acid-maleic acid copolymer		5.0	5.0
Sodium polyacrylate			0.0
Sodium citrate			0.0
Amorphous aluminosilicate		4.6	4.6
Polyethylene glycol		1.0	1.0
Sodium carbonate			0.0
Potassium carbonate			0.0
JIS No. 1 Liquid glass			0.0
Sodium sulfate		6.0	6.0
Sodium sulfite		1.0	1.0
Fluorescent Dye S			0.0
Fluorescent Dye T		0.4	0.4
Water Content		1.5	1.5
Average Particle Size (µm)	〈452〉	〈405〉	〈435〉
Amount of Each Granule	51.0	47.5	―
Total of Both Granules	98.5	98.5
After-Blend	Protease Granules	0.5	0.5
Cellulase Granules	0.5	0.5
Lipase Granules	0.3	0.3
Perfumes	0.2	0.2
Grand Total of Entire Composition	100.0	100.0
Detergency (%)	70.2	63.6

(Parts by Weight)
	Example 2	Comparative Example 2
	Crystalline Silicate Granule II	Metal Ion Capturing Agent Granule II
A)	Polyoxyethylene alkyl ether	11.0		11.0
Sodium alkylbenzenesulfonate		10.0	10.0
Sodium alkyl (C=14) sulfate		2.0	2.0
Palmitic acid			0.0
Semi-Cured Tallow Fatty Acid	2.5		2.5
B)	Crystalline Silicate A	30.5		30.5
Crystalline Silicate B			0.0
C)	4A-Type Zeolite	3.0	20.0	23.0
Acrylic acid-maleic acid copolymer		2.0	2.0
Sodium polyacrylate		1.0	1.0
Sodium citrate		2.0	2.0
Amorphous aluminosilicate			0.0
Polyethylene glycol	2.5		2.5
Sodium carbonate			0.0
Potassium carbonate			0.0
JIS No. 1 Liquid glass		3.0	3.0
Sodium sulfate		5.0	5.0
Sodium sulfite		1.0	1.0
Fluorescent Dye S		0.3	0.3
Fluorescent Dye T			0.0
Water Content		2.7	2.7
Average Particle Size (µm)	〈468〉	〈426〉	〈430〉
Amount of Each Granule	49.5	49.0	―
Total of Both Granules	98.5	98.5
After-Blend	Protease Granules	0.5	0.5
Cellulase Granules	0.5	0.5
Lipase Granules	0.3	0.3
Perfumes	0.2	0.2
Grand Total of Entire Composition	100.0	100.0
Detergency (%)	68.3	62.4

(Parts by Weight)
	Example 3	Comparative Example 3
	Crystalline Silicate Granule III	Metal Ion Capturing Agent Granule III
A)	Polyoxyethylene alkyl ether	10.0	1.2	11.2
Sodium alkylbenzenesulfonate		5.0	5.0
Sodium alkyl (C=14) sulfate		8.0	8.0
Palmitic acid			0.0
Semi-Cured Tallow Fatty Acid			0.0
B)	Crystalline Silicate A			0.0
Crystalline Silicate B	25.0		25.0
C)	4A-Type Zeolite	3.0	19.0	22.0
Acrylic acid-maleic acid copolymer		3.0	3.0
Sodium polyacrylate			0.0
Sodium citrate			0.0
Amorphous aluminosilicate	6.0		6.0
Polyethylene glycol	4.0		4.0
Sodium carbonate		1.5	1.5
Potassium carbonate			0.0
JIS No. 1 Liquid glass		2.5	2.5
Sodium sulfate		6.0	6.0
Sodium sulfite		1.0	1.0
Fluorescent Dye S	0.2		0.2
Fluorescent Dye T		0.3	0.3
Water Content		2.8	2.8
Average Particle Size (µm)	〈465〉	〈407〉	〈410〉
Amount of Each Granule	48.2	50.3	―
Total of Both Granules	98.5	98.5
After-Blend	Protease Granules	0.9	0.9
Cellulase Granules	0.2	0.2
Lipase Granules	0.2	0.2
Perfumes	0.2	0.2
Grand Total of Entire Composition	100.0	100.0
Detergency (%)	65.8	60.8

The results presented above indicate that the detergent compositions of Examples of the present invention, each comprising granules containing a crystalline alkali metal silicate component and granules containing a metal ion capturing agent component, wherein the crystalline alkali metal silicate component and the metal ion capturing agent component are substantially contained in separate granules, show further improved detergency rates when compared to those of Comparative Examples which had the same composition as the corresponding Examples, wherein the crystalline alkali metal silicate component and the metal ion capturing agent component are all contained in one granule.

In addition, a detergent formulated with 36.0 parts by weight of the crystalline alkali metal silicate granules (I) and 62.5 parts by weight of the metal ion capturing agent granules (II) prepared in Example 1, and balance being the same as the after-blended product of Example 1 is prepared, and a detergency test is carried out under the following conditions.

The detergency test is carried out by changing the water used to 8°DH, the washing temperature to 30°C, and the used concentration to 1.2 g/L. Other conditions are the same as Test Example. As a result, when compared to a detergent composition comprising the crystalline alkaline metal silicate component and the metal ion capturing agent component in the same granule, excellent detergency can be obtained.

Further, a detergent formulated with 20.0 parts by weight of the crystalline alkali metal silicate granules (I) and 78.5 parts by weight of the metal ion capturing agent granules (II) prepared in Example 1, and balance being the same as the after-blended product of Example 1 is prepared, and a detergency test is carried out under the following conditions.

The detergency test is carried out by changing the water used to 15°DH, the washing temperature to 40°C, and the used concentration to 2.5 g/L. Other conditions are the same as Test Example. As a result, when compared to a detergent composition comprising the crystalline alkaline metal silicate component and the metal ion capturing agent component in the same granule, excellent detergency can be obtained.

INDUSTRIAL APPLICABILITY

Since a high-density granular detergent composition of the present invention comprises the granules containing the crystalline alkali metal silicate and the granules containing the metal ion capturing agent, wherein each of the granules is contained in the detergent composition as separate granules, an excellent detergency can be exhibited with a smaller standard amount of dosage.

The present invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.

Claims

A high-density granular detergent composition comprising:

A) one or more surfactants;

B) one or more crystalline alkali metal silicates having an SiO₂/Na₂O molar ratio of from 0.5 to 2.6; and

C) one or more metal ion capturing agents other than Component B, having a calcium ion capturing ability of 200 CaCO₃ mg/g or more,
wherein a total amount of Component A, Component B, and Component C is from 70 to 100% by weight of the entire granular detergent composition, wherein a weight ratio of Component B to Component A is B/A = 9/1 to 9/11, and wherein a weight ratio of Component B to Component C is B/C = 4/1 to 1/15,

wherein said high-density granular detergent composition comprises granules (I) containing the crystalline alkali metal silicate of Component B and granules (II) containing the metal ion capturing agents of Component C, said granules (I) and said granules (II) being present substantially in separate granules.
The high-density granular detergent composition according to claim 1, wherein the amount of the alkalizing agents other than the crystalline alkali metal silicates of Component B is 20% by weight or less in the entire granular detergent composition.
The high-density granular detergent composition according to claim 1 or 2, wherein the content of sodium carbonate is 10% by weight or less in the entire granular detergent composition.
The high-density granular detergent composition according to any one of claims 1 to 3, wherein the granules (I) have an average particle size of from 300 to 1000 µm.
The high-density granular detergent composition according to any one of claims 1 to 4, wherein ingredients including Component B in the granules (I) are coated with binders comprising organic substances.
The high-density granular detergent composition according to claim 5, wherein said binders comprise nonionic surfactants, the nonionic surfactants being contained in an amount of 50% by weight or more of the binders.
The high-density granular detergent composition according to claim 5 or 6, wherein said binders are selected from:

1) one or more nonionic surfactants;

2) a mixture comprising one or more nonionic surfactants and one or more gel-formable anionic surfactants;

3) a mixture comprising one or more nonionic surfactants and one or more polyethylene glycols having weight-average molecular weights of 3000 or more; and

4) a mixture comprising one or more nonionic surfactants, one or more gel-formable anionic surfactants, and one or more polyethylene glycols having weight-average molecular weights of 3000 or more.
The high-density granular detergent composition according to any one of claims 1 to 7, wherein the crystalline alkali metal silicate of Component B is represented by the following formula (1): xM₂O·ySiO₂·zMe_mO_n·wH₂O, wherein M stands for an element in Group Ia of the Periodic Table; Me stands for one or more members selected from the group consisting of elements in Group IIa, IIb, IIIa, IVa, and VIII of the Periodic Table; y/x is 0.5 to 2.6; z/x is 0.01 to 1.0; n/m is 0.5 to 2.0; and w is 0 to 20.
The high-detergent granular detergent composition according to any one of claims 1 to 7, wherein the crystalline alkali metal silicate of Component B is represented by the following formula (2): M₂O·x'SiO₂·y'H₂O, wherein M stands for an alkali metal atom; x' is 1.5 to 2.6; and y' is 0 to 20.