EP0426876A1

EP0426876A1 - Detergent composition

Info

Publication number: EP0426876A1
Application number: EP90907473A
Authority: EP
Inventors: Isao 4594 Ichihana Ichikaimachi Yamada; Nobuyoshi 4599-1 Ichihana Yamaguchi; Akira 4-12 Izumigaoka 2-Chome Suzuki; Tatsuhiro 3-45 Wakaurahigashi 4-Chome Imanaka; Hiromoto 44 Tosacho 1-Chome Mizushima; Shoji 3-30-301 Nishikoniri 3-Chome Nakagawa
Original assignee: Kao Corp
Current assignee: Kao Corp
Priority date: 1989-05-29
Filing date: 1990-05-29
Publication date: 1991-05-15
Also published as: EP0426876A4; JP2843112B2; WO1990015128A1; JPH03277696A

Abstract

A detergent composition exhibiting an excellent detergency especially on inorganic stains adherent to clothing, which comprises (a) an nonionic surfactant, and (b) an anionic surfactant having at least one hydrophobic C₆ to C₂₄ hydrocarbon group and at least two anionic groups, wherein a stability constant of chelating with calcium ion is at least 2 and a Krafft point upon chelating with calcium ion is 5°C or below.

Description

Field of the Invention

The present invention concerns a detergent composition and, more in particular, it relates to a detergent composition having excellent detergent power to inorganic contaminations on cloths.

Prior Art

Contaminations on cloths are generally classified into organic dirts and inorganic dirts. In cloths such as underwears the organic dirts mainly comprise skin fat dirts derived from bodies. Detergents containing non-ionic surface active agents show excellent detergent power to oil contaminations such as skin fat dirts. On the other hand, inorganic dirts mainly comprise dusts suspending in air or mud derived from soils. Generally organic and inorganic contaminations are present together in cloth contaminations and conventional detergents have insufficient detergent power to inorganic dirts, in particular, mud deposited to socks, etc.

Disclosure of the Invention

The present inventors have made an earnest study and, as a result, have accomplished the present invention based on the finding that a detergent composition remarkably improved with a detergent power to inorganic dirts can be obtained by using a non-ionic surface active agent and a specific anionic surface active agent together.
That is, the present invention provides a detergent composition containing:

(a) a non-ionic surface active agent and
(b) an anionic surface active agent having at least one hydrophobic group with 6 to 24 carbon atoms and two or more anionic groups, in which
- (1) the chelate stabilization constant to calcium ions is not less than 2 and
- (2) a kraft point upon chelating calcium ions is not higher than 5°C.

The non-ionic surface active agent as the ingredieint

(a) in the present invention has no particular restrictions and the following agents can be exemplified.
- (1) Polyoxyethylene alkyl or alkenyl ether having an alkyl or alkenyl group with 10 to 20 carbon atoms in average and also having 1 to 20 mol of ethylene oxide added thereto.
- (2) Polyoxyethylene alkyl phenyl ether having an alkyl group with 6 to 12 carbon atoms in average and also having 1 to 20 mol of ethylene oxide added thereto.
- (3) Polyoxypropylene alkyl or alkenyl ether having an alkyl or alkenyl group with 10 to 20 carbon atoms in average and also having 1 to 20 mol of propylene oxide added thereto.
- (4) Polyoxybutylene alkyl or alkenyl ether having an alkyl or alkenyl group with 10 to 20 carbon atoms in average and also having 1 to 20 mol of butylene oxide added thereto.
- (5) Non-ionic surface active agent having alkyl or alkenyl group with 10 to 20 carbon atoms in average and also having 1 to 30 mol in total of ethylene oxide and propylene oxide or ethylene oxide and butylene oxide added thereto to (the ratio of ethylene oxide and propylene oxide or butylene oxide is from 0.1/9.9 to 9.9/0.1).
- (6) Higher fatty acid alkanol amide represented by the following general formula or its alkylene oxide adduct.
  where R'₁ is an alkyl or alkenyl group with 10 to 20 carbon atoms, R'₂ is H or CH₃, n₁ is an integer of 1 to 3 and m₁ is an integer of 0 to 3.
- (7) Sucrose-fatty acid ester comprising a fatty acid with 10 to 20 carbon atoms in average and sucrose.
- (8) Fatty acid glycerine monoester comprising a fatty acid with 10 to 20 carbon atoms in average and glycerine.
- (9) An alkyl amine oxide represented by a following general formula:
  where R'₃ is an alkyl or alkenyl group with 6 to 20 carbon atoms, R'₄ is an alkyl or hydroxyalkyl group with 1 to 3 carbon atoms or a polyoxy ethylene group having 2 to 7 ethylene oxide groups and R'₅ is R'₃ or R'₄
- (10) Alkyl glycocide represented by the following general formula:
  
  R'₆(OR'₇)_xG_y
  
  where R'₆ represents a linear or branched alkyl, alkenyl or alkylphenyl group with 8 to 18 carbon atoms, R'₇ represents an alkylene group with 2 to 4 carbon atoms, G represents a residue derived from a reducing sugar having 5 to 6 carbon atoms, x is a number in average of 0 to 5, preferably, 0 to 2, and y is a number in average of 1 to 10, preferably, 1.1 to 3. As the reducing sugar with 5 to 6 carbon atoms, there can be mentioned glucose, fructose, maltose and sucrose.
- (11) Polypropylene glycol-polyethylene oxide adduct in which the molecular weight of polypropylene glycol is from 1000 to 4000 and average addition mol number of polyethylene oxide is 10 to 60.

The non-ionic surface active agent (a) having HLB of 6 to 19, preferably 8 to 17 is usually used. Among all, the non-ionic surface active agent represented by (1), (2), (5) or (10) is particularly preferred. The non-ionic surface active agent (a) is blended by 1 to 90 % in the composition.
The anionic surface active agent used as the ingredient (b) in the present invention is an anionic surface active agent having at least one hydrophobic group with 6 to 24 carbon atoms and two or more anionic groups, in which the chelate stabilization constant to calcium ions is not less than 2 and the kraft point upon chelating calcium ions is not higher than 5°C.
The anionic surface active agent having the foregoing feature is different from Na salt of linear alkyl benzene sulfonic acid or sodium salt of polyoxyethylene alkyl ether sulfuric ester in view of the following points.
One of them is a chelating effect to calcium ions. It is considered that actual contaminations comprise polyvalent cations such as calcium, magnesium, iron and aluminum in the contamination ingredients, which are present between negatively charged fibers and negatively charged contamination particles and serve to bond them. It is considered that such polyvalent cation bridges are rather important factor for the deposition of contaminations and the anionic surface active agent in the present invention has a nature of chelating such metal ions and those having Ca²+ chelate stabilization constant of not less than 2 particularly contribute to the improvement of the detergent power.
It is further considered that ions such as Ca²⁺ and Mg²⁺ present in water, in particular, Ca²⁺ cause undesired effects such as recontaminations if they are not chelated and the anionic surface active agent in the present invention is useful also in this point.
If the surface active agent has a kraft point upon chelating the calcium ions of not higher than 5°C, preferably, not higher than 0°C, such an anionic surface active agents remains to serve as the surface active agent after chelating the calcium ions and, accordingly, can provide a detergent power being free from the effect of the hard ingredient even under low temperature washing conditions as in Japan.
In addition, since the anionic surface active agent in the present invention has a plurality (two or more) of anionic groups, they are adsorbed on solid particles to increase negative zeta potential to, thereby increase the repulsion between solid particles having identical static charges. Since these charges are scarcely lost under usual washing conditions, contaminations are detached from the surface to be washed.
From the foregoings, it can be said that the anionic surface active agent according to the present invention is a surface active agent capable of remarkably improving a detergent power to inorganic dirts, in particular, mud deposited to socks, etc. which can not be cleaned sufficiently with conventional detergent containing anionic surface active agent.
The chelate stabilization constant to calcium ions and the kraft point upon chelating the calcium ions of the anionic surface active agent as the ingredient (b) in the present invention are values measured by the following measuring methods.

1. Method of measuring Ca ion capturing performance by calcium ion electrode

Solutions are prepared by using the following buffer solution: Buffer solution : 0.1M-NH₄Cl-NH₄OH buffer (pH 10.0)

(1) Preparation of calibration curve

A standard calcium ion solution is prepared and a calibration curve showing a relationship between the calcium ion concentration (log) and the potential as shown in Fig. 1 is prepared.

(2) Measurement for calcium ion capturing performance

About 0.1 g of a specimen (anionic surface active agent) is weighted into 100 ml of messflask, to which the buffer solution described above was added. An aqueous solution of CaCl₂ (pH 10.0) corresponding to 20000 ppm (as CaCO₃) is dropped from a burette (blank is also measured).
The aqueous solution of CaCl₂ is added each by 0.1 - 0.2 ml upon dropping and the potential is read on every dropping to determine a calcium ion concentration based on the calibration curve shown in Fig. 1. The calcium ion concentration at the dropping amount A of the specimen shows a calcium ion capturing performance of the specimen (in Fig. 2).

(3) Calculation for the calcium ion chelate stabilization constant

The result for the measurement of Ca²⁺ capturing performance is used for the calcium ion chelate stabilization constant (pKCa²⁺). Calculation is based on the assumption that 1:1 complex is formed when an equimolar amount of calcium is added to the specimen (anionic surface active agent).
The stabilization constant of the complex can be determined in accordance with the following equations:
M + L ⇄ ML
^(M)TOTAL = (ML) + (M)
^(L)TOTAL = (ML) + (L)
^KML = (ML)/(M)(L)
Stability constant of complex pKMⁿ⁺ = log ^KML

2. Method for measuring the kraft point upon chelating calcium ions

An anionic surface active agent and an equimolar amount of CaCl₂ are added to an aqueous solution of the anionic surface active agent at 0.1 wt% concentration. The solution is cooled to not higher than 0°C and then the temperature is elevated at a rate of less than 1°C for one min. The kraft point is defined as not higher than 0°C if there is no insoluble matters and the temperature at which insoluble matters, if any, are dissolved is defined as the kraft point.
The anionic surface active agent used in the present invention has a chelate stabilization constant to calcium ions (pKCa²⁺) of not less than 2, preferably, not less than 3 and, more preferably, not less than 4 and the kraft point upon chelating the calcium ions of not higher than 5°C and, preferably, not higher than 0°C. The anionic surface active agent having such physical property can effectively catch the hard ingredients in tap water, as well as effectively improve the detergent power when used together with the non-ionic surface active agent.
The anionic surface active agent in the present invention preferably has the calcium ion capturing performance of not less than 50 mg/g, preferably, 100 mg/g and, more preferably, 200 mg/g converted as CaCO₃.
The anionic group of the anionic surface active agent according to the present invention is carboxylic acid group, sulfonic acid group, etc. and, preferably, it has at least one and, more preferably, two or more carboxylic acid groups. Such physical property is not found in anionic surface active agents used so far in conventional detergents such as alkylbenzene sulfonate salt, alkyl ether sulfonate salt, olefin sulfonate salt, α-sulfo fatty acid ester salt, alkane sulfonate salt, higher fatty acid salt, alkenyl succinic acid salt, sulfosuccinic acid salt, etc.
The anionic surface active agent usable in the present invention is to be exemplified with no particular restrictions.

(i) Anionic surface active agent represented by the following general formula (I)
where
in which R₃ is a linear or branched saturated or unsaturated hydrocarbon group with 6 to 20 carbon atoms or the hydrocarbon group further having 1 to 7 oxyethylene group added thereto, R₄ represents hydrogen or a linear, branched or cyclic saturated or unsaturated hydrocarbon group with 1 to 6 carbon atoms, R₂: identical with R₁ or represents -OX in which X represents H, alkali metal, alkaline earth metal, ammonium or alkanol ammonium, at least two of R₂ represent -ox, n : 1 or 2 More specifically, the surface active agent is an ester or amide derivative of diethylenetriamine pentaacetate (hereinafter referred to as DTPA), triethylenetetramine hexa-acetate (hereinafter referred to as TTHA). Among them, ester derivative mono- or di-, particularly di-ester derivative, diamide derivative mono- or di-, particularly di-amide derivative of DTPA, and di- or tri-ester derivative, di- or tri-amide derivative of TTHA are preferred. Specifically, there can be exemplified DTPA dioctylester, DTPA didecylester, DTPA dioctylamide, DTPA didodecylamide, DTPA distearylamide, DTPA di(triethyleneglycoldodecyl)ester, TTHA didecyl ester, TTHA tridodecylamide and salts thereof.
(ii) Anionic surface active agent represented by the following general formula (II)
where R₁ : alkyl group, hydroxy alkyl group, alkyl phenyl group, hydroxyalkylphenyl group, alkylbenzyl group, polyoxyalkylene alkyl ether group or polyoxyalkylene alkylphenyl ether group (in which the alkyl group has 8 to 18 carbon atoms),
(in which R₇ represents H or alkyl group with 1 to 3 carbon atoms, n is 2 or 3 and 1 is 1 - 7)

m :

0 or 1,

y :

(̵CH₂)̵_p (in which p is 1 to 3)

n :

0 or 1,

R₂, R₃, R₄, R₅, R₆:
one of them represents -OH group, one or two of them represents -CH₂-N(CH₂COOM)₂ and the other of them represents -H or -SO₃M in which M is H, alkali metal, alkaline earth metal, ammonium or alkanol ammonium.

The anionic surface active agent represented by the general formula (II) can be synthesized from commercially available phenol or phenol derivatives by means of one step Mannich reaction. Specifically, it can be synthesized by the method described in Helv. Chim. Acta 35, 1785 (1952) or "Chemistry of EDTA Complexane" edited by Keihei Ueno, p 99 - 105, published from Nankodo (1977).
Typical specific examples of the compounds represented by the general formula (II) are shown below.

(iii) Anionic surface active agent represented by each of the following formulae.

In the above, the kraft point for each of the compounds shows a value when chelating calcium ions.
The anionic surface active agent for the ingredient (b) in the present invention is blended by 0.1 to 90% in the composition.
For improving the detergent effect, it is desirable to blend the ingredients (a) and (b) at the composition ratio (a)/(b) (by weight ratio) of 100/1 - 1/20, preferably, 100/1 - 1/10, more preferably, 10/1 - 1/10. If the weight ratio is less than 100/1, no sufficient effect for improving the detergent power to inorganic dirts can be obtained.
In the detergent composition according to the present invention, those agents employed generally so far, for example, the following amphoteric surface active agent and anionic surface active agent can be blended in addition to the essential ingredients as described above.

(1) An amphoteric surface active agent represented by the following general formula:
where R'₈ represents an alkyl or alkenyl group with 8 to 20 carbon atoms R'₉ represents an alkyl group with 1 to 3 carbon atoms, R'₁₀ represents an alkylene or hydroxyalkylene group with 1 to 6 carbon atoms and X represents COO⁻ or SO₃⁻.
(2) A linear or branched alkyl benzene sulfonate salt having an alkyl group with 10 to 16 carbon atoms in average.
(3) An alkyl or alkenyl ether sulfate salt having a linear or branched alkyl or alkenyl group with 10 to 20 carbon atoms in average, in which ethylene oxide or propylene oxide or ethylene oxide/propylene oxide (= 0.1/9.9 - 9.9/0.1) are added in average in one molecule.
(4) An alkyl or alkenyl sulfate salt having an alkyl or alkenyl group with 10 to 20 carbon atoms in average.
(5) An olefin sulfonate salt having 10 to 20 carbon atoms in average in one molecule.
(6) An alkane sulfonate salt having 10 to 20 carbon atoms in average in one molecule.
(7) An α-sulfo fatty acid salt or ester represented by the following formula :
where Y represents an alkyl group with 1 to 3 carbon atoms or a pair ion, Z represents a pair ion and R'₁₁ represents an alkyl or alkenyl group with 10 to 20 carbon atoms.
(8) A higher fatty acid salt with 10 to 20 carbon atoms in average

As the pair ion for the anionic surface active agent, there can be mentioned alkali metal ion such as of sodium and potassium, alkaline earth metal ion such as of magnesium, ammonium ion, or alkanol amine having 1 to 3 alkanol groups with 2 or 3 carbon atoms (for example, monoethanolamine, diethanolamine, triethanolamine, triisopropanolamine).
In the detergent composition according to the present invention, organic or inorganic alkali agents such as silicate, carbonate, hydrogen carbonate, caustic alkali or ethanolamine can be blended.
Further, in the detergent composition according to the present invention, inorganic bivalent metal ion chelating agent such as synthetic zeolite or layerous silicate, or organic bivalent metal ion chelating agent shown below can be blended.

(1) Salts of amino acid such as aspartic acid or glutamic acid.
(2) Aminopolyacetic acid salt such as nitrilo triacetate salt, imino diacetate salt, ethylenediamine tetraacetate salt, diethylenetriamine pentaacetate salt, glycol ether diamine tetraacetate salt, hydroxyethylimino diacetate salt, triethylenetatramine hexaacetate salt, dienekolic acid salt.
(3) Salts of polymeric compounds such as polyacrylic acid, polyaconitic salt, polyitaconic acid, polycitraconic acid, polyfumaric acid, polymaleic acid, poly mesaconic acid, poly- α -hydroxyacrylic acid, sulfonated polymaleic acid, maleic acid anhydride-diisobutylene copolymer, maleic acid anhydride - styrene copolymer, maleic acid anhydride - methyl vinyl ether copolymer, maleic acid anhydride - ethylene copolymer, maleic acid anhydride - ethylene crosslinking copolymer, maleic acid anhydride - vinyl acetate copolymer, maleic acid anhydride - acrylonitrile copolymer, maleic acid anhydride - acrylic ester copolymer, maleic acid anhydride - butadiene copolymer, maleic acid anhydride - isoprene copolymer, poly-β-ketocarboxylic acid derived from maleic acid anhydride and carbon monoxide, itaconic acid - ethylene copolymer, itaconic acid - aconitic acid copolymer, itaconic acid - maleic acid copolymer, itaconic acid - acrylic acid copolymer, malonic acid methylene copolymer and mesaconic acid - fumaric acid copolymer.
(4) Salts of dicarboxylic acids such as oxalic acid malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid and decane-1,10-dicarboxylic acid; salts of diglycolic acid, thiodiglycolic acid, oxal acetic acid, oxydisuccinic acid, carboxymethyloxy succinic acid and carboxymethyltartronic acid; salts of malic acid, tartaric acid, succinic acid, itanocnic acid, methyl succinic acid, 3-methyl glutaric acid, 2,2-dimethyl-malonic acid, maleic acid, furamic acid, 1,2,3-propane tricarboxylic acid, aconitic acid, 3-butene-1,2,3-tricarboxylic acid, butane-1,2,3,4-tetracarboxylic acid, ethane tetracarboxylic acid, ethene tetracarboxylic acid, n-alkenyl aconitic acid, 1,2,3,4-cyclopentane tetracarboxylic acid, phthalic acid, trimesic acid, hemimellitic acid, pyromellitic acid, benzene hexacarboxylic acid, tetrahydrofuran-1,2,3,4-tetracarboxylic acid and tetrahydrofuran-2,2,5,5-tetracarboxylic acid; salts of sulfonated carboxylic acids such as sulfotricarballylic acid and sulfosuccinic acid; carboxymethylation products such as sucrose, lactose and raffinose, carboxymethylation product of pentaerythritol, carboxymethylation product of gluconic acid, condensation product of polyhydric alcohol or saccharide with maleic acid anhydride or succinic acid anhydride, condensation product of oxycarboxylic acid and maleic acid anhydride or succinic acid anhydride, salt of organic acids such as C.M.O.S, builder-M and builder-U.

As a solubilizing agent used for enhancing the viscosity reducing effect and coagulation preventive effect at low temperature in the case of preparing the detergent composition according to the present invention into a liquid detergent, particularly, with less content of the ingredient (b), there can be mentioned lower alcohols such as ethanol and isopropanol; polyhydric alcohols such as ethylene glycol, propylene glycol, glycerine and sorbitol; aromatic sulfonate salts such as benzene sulfonate salt, acetylbenzene sulfonate salt, p-toluene sulfonate salt and m-xylene sulfonate salt; acetoamides, pyridine carboxylic acid amides, benzoic acid salt or urea. Among the solubilizing agents as described above, use of ethanol is particularly preferred since it can serve also for preventing bacteria growth occurring upon long time storage of the liquid detergent.
Basic formulations of the heavy liquid detergent blended with bivalent metal ion chelating agent and solubilizing agent will be shown below.

(a) Non-ionic surface active agent
(b) Anionic surface active agent according to the present invention
(c) Bivalent metal ion chelating agent: 0.5 - 10 wt%, preferably, 1 - 7 wt%
(d) Solubilizing agent : 1 - 10 wt%, preferably, 3 - 7 wt%

In the formulation as described above, the blending ratio of the ingredient (a) and the ingredient (b) is from 20/1 to 1/10, preferably, 10/1 to 1/5 as (a)/(b) (weight ratio) and 5 to 60 wt% and, preferably, 20 to 60 wt% as the total for (a)+(b).
The heavy liquid detergent composition as described above can further be blended with a saturated or unsaturated fatty acid with 10 to 20 carbon atoms such as coconuts oil, beef tallow fatty acid, palm fatty acid or the salts thereof for further improving the detergent power, without deteriorating the store stability. The fatty acid or the salts thereof is an ingredient also desired for the improvement of rinsing property and is preferably blended by 0.5 to 5 wt% in the composition.
In the heavy detergent composition, the store stability is kept satisfactory if the bivalent metal ion chelating is blended by a great amount than usual composition.
In the liquid detergent composition according to the present invention, there can be further blended as other optional ingredients depending on the purpose, for example, extender such as sodium sulfate; re-contamination preventive agent such as carboxymethyl cellulose, polyethylene glycol, polyacrylic acid salt, copolymer of maleic acid anhydride and acrylic acid or olefin; bleaching agent such as percarbonate or perborate; enzyme such as protease, lipase, cellulase or amylase, enzyme stabilizer such as calcium chloride; bleaching activator, fluorescent dye, pigment, preserver, perfume, etc.
Remarkable merits of the detergent composition according to the present invention are that it can provide a detergent effect, particularly, for inorganic solid contaminations, for example, contaminations with fine mud that can not be washed off sufficiently by conventional detergents, that it is effective also for contaminations such as dirts on collars and cuffs and oil stains, as well as that it is extremely useful for the improvement of the detergent power of non-phosphorus inorganic detergents.
Detergents containing phosphates have been effective for the removal of contaminations with fine mud intruding between the fibers. However, since the blending amount of the phosphates in the detergents, etc. has tended to be reduced in view of the eutrophication problems and non-phosphatization is obliged at present, removal of mud contaminations becomes difficult. As is well known, removal of contaminations with mud intruding into cotton cloths is quite difficult. Further, mud contaminations deposited firmly to canvas shoes made of cotton-mixed cloth trouble house wives.
The detergent composition according to the present invention can provide a solution for such problems. That is, when the composition according to the present invention is applied, for example, to non-phosphate alkaline detergent, a detergent having excellent detergent power which is comparable with or superior to a weakly alkaline detergent containing a sufficient amount of phosphate can be obtained for cleaning contaminations with mud intruding mixed-spun cloths of cellulose fibers and other fibers.

DESCRIPTION OF THE ACCOMPANYING DRAWINGS

Fig. 1 is a calibration curve for determining calcium concentration based on potential and
Fig. 2 a graph illustrating a relationship between calcium ion concentration and the addition amount of aqueous CaCl₂ solution.

EXAMPLE

The present invention will be described more specifically referring to examples but it should be noted that the invention is not always restricted to such examples.

Example 1

Various kinds of detergent compositions having ingredients as shown in Table-1 were prepared and the detergent power for each of them was evaluated by the following method.

Mud-contaminated cloth (artificially contaminated cloth)

After drying Kanuma Akadama soils (horticultural soils) at 120° C ± 5°C for 4 hours and pulverizing them, fractions passing at 150 mesh (100 µm) size were dried at 120°C ± 5°C for 2 hr and ± 150 g was dispersed in 1000 liter perchloroethylene. Then, unbleached muslin #2023 cloth was brought into contact with the liquid, and brushed, to remove liquid dispersion and remove contaminations deposited in excess (Japanese Patent Laid-Open Sho 55-26473).

Skin fat-contaminated cloth (artificially contaminated cloth)

The model skin fat contamination comprising the above mentioned composition was uniformly coated by 2g on a 10 x 10 cm cotton cloth.

Washing condition and evaluation method

Five sheets of mud-contaminated cloth or skin fat contaminated cloth made of cotton (artificially contaminated cloth) each sized 10 cm x 10 cm were placed in one liter of an aqueous detergent solution used for evaluation and washed by a Terg-O-Tometer under the condition of 100 rpm. The washing conditions were as below.
For measuring the detergent power, the reflectance at 460 mµ of cloths not contaminated and contaminated cloths before and after washing was measured by self recording color meter (manufactured by Shimazu Seisakusho) and the detergent rate (%) was determined in accordance with the following equation (the ratio is shown in the table as the average of measured value for 5 sheets).
pKCa²⁺ kraft point upon chelating calcium ions and Ca capturing performance (mg/g, as CaCO₃) of (1) - (5) for the ingredient (b) in Table 1 are as below.

Example 2

Various kinds of detergent compositions having ingredients shown in Table-2 were prepared and the detergent power for each of them was measured by the following washing conditions.

Washing conditions

Five sheets of mud-contaminated cloth or skin fat-contaminated cloth (artificially contaminated cloth) each sized 10 cm x 10 cm were placed in one liter of an aqueous detergent solution used for evaluation and washed by a Terg-O-Tometer at 100 rpm under the following conditions. The washing conditions are as shown below.
pKCa²⁺ , kraft point upon chelating calcium ions and Ca capturing performance (mg/g, as CaCO₃) of II-5, II-9, II-10, II-15, III-3, III-5 and III-6 for the ingredient (b) in Table-2 are as shown below

Example 3

The liquid detergent compositions having ingredients shown in Table-3 were prepared and their store stability were evaluated respectively by the following method.

(Store stability)

Each of specimens were put into a screw tube (4 cm diameter, 10 cm height), stored at 40°C and -5°C and coagulation, separation and deposition were judged by naked eyes after one month storage.
The evaluation standards are as shown below.

o :: liquid remained clear
x :: coagulation, separation or deposition occurred

The results of the evaluation are shown in Table-3.
pKCa²⁺, kraft point upon chelating calcium ions and Ca capturing performance (mg/g, as CaCO₃) of (6), (7) and (8) for the ingredient (b) in Table-3 are as shown below.

Example 4

Liquid detergent compositions having ingredients shown in Table-4 were prepared and their store stability were evaluated in the same procedures as in Example 3 and the detergent power was evaluated by the following method.

Washing condition

Five sheets of mud-contaminated cloths made of cotton (artificially contaminated cloths) each sized 10 cm x 10 cm were placed in one liter of an aqueous detergent solution used for evaluation and washed in a Terg-O-Tometer at 100 rpm under the following conditions.
The washing conditions are as below.
The results of the evaluation are shown in Table-4.
pKCa²⁺, kraft point upon chelating calcium ions and Ca capturing performance (mg/g, as CaCO₃) of (9) and (10) for the ingredient (b) in Table-4 are as shown below.

Example 5

Powdery detergent compositions having ingredients as shown in Table-5 were prepared and their detergent performance was evaluated respectively in the same procedures as those in Example 2.
The results are shown in Table-5
pKCa²⁺, kraft point upon chelating calcium ions and Ca capturing performance (mg/g, as CaCO₃) of (11), (12) and (13) for the ingredient (b) in Table-5 are as shown below.

Claims

A detergent composition comprising;
(a) a non-ionic surface active agent and

(b) an anionic surface active agent having at least one hydrophobic group with 6 to 24 carbon atoms and two or more anionic groups, in which
(1) a chelate stabilization constant to calcium ions is not less than 2,

(2) a kraft point upon chelating calcium ions is not higher than 5°C.
A detergent composition as defined in claim 1, wherein, a calcium ions capturing performance of the anionic surface active agent is not less than 50 mg (as CaCO₃)/g.
A detergent composition as defined in claim 1 or claim 2, wherein, the weight ratio (a)/(b) for the ingredient (a) and the ingredient (b) is from 100/1 to 1/20.
A detergent composition as defined in any one of claims 1 to 3 wherein, the composition further contains an alkali agent and/or bivalent metal ion capturing agent.
A detergent composition as defined in any one of claims 1 to 4 wherein, phosphoric ingredient is not contained.