JP2003041479A - Washing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a washing method by which excellent washing performance to stain derived from a human such as collar stain or sleeve stain can simply be obtained. SOLUTION: (a) A material to be washed is brought into contact with a pre-treating agent composition containing 1-30 wt.% chelating agent and water and (b) the pre-treated material to be washed is brought into contact with after-treating composition containing 0.005-0.2 wt.% surfactant and water.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for washing clothes. More specifically, it relates to a washing method having a two-step treatment process.

[0002]

2. Description of the Related Art In the case of severe stains on collar sleeves and spilled foods, stains may not be sufficiently removed by ordinary washing, or stains may remain. In general, collar sleeves and stain stains are dealt with by directly applying a detergent to partially increase the detergent concentration.

For example, JP-A-60-101199,
Japanese Unexamined Patent Application Publication No. 10-298599 discloses an applied cleaning agent which is applied to an object to be cleaned and then washed. However, according to the contents disclosed by these, the detergency is insufficient, and especially the detergency against human-derived stains such as collar sleeve stains is insufficient.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a washing method which can easily obtain excellent washing performance. In particular, it is to provide a washing method capable of obtaining excellent cleaning performance against stains of human origin such as stains on the collar and sleeves.

[0005]

SUMMARY OF THE INVENTION The present invention provides an article to be cleaned,
After contacting with a pretreatment agent composition (a) containing a chelating agent [hereinafter referred to as (a1) component] 1 to 30% by mass and water [hereinafter referred to as (a2) component], a surfactant [hereinafter referred to as (B1) component] 0.005 to 0.2% by mass and water [hereinafter referred to as (b2) component] to a (b) post-treatment composition.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The washing method of the present invention is particularly suitable for partial stains such as collar stains, sleeve stains, and stain stains, and is more suitable for human-derived stains such as collar stains and sleeve stains. Is the way.

The contact between the article to be cleaned and the (a) pretreatment composition may be carried out by immersing the article to be cleaned in the (a) pretreatment composition, but in terms of simplicity, For washed items (a)
It is more preferable to carry out by applying the pretreatment composition. As a coating method, (a) the pretreatment composition may be directly coated through a hole in the container discharge portion, may be coated through a sponge, a brush or a roll, or may be coated in a measuring container. However, in terms of convenience, it is more preferable to apply the composition in the form of spray or foam, and in order to prevent the user from inhaling a fine mist, it is more preferable to apply it in the form of foam.

In the present invention, after the object to be cleaned is brought into contact with (a) the pretreatment composition, the object to be cleaned is (b) the posttreatment composition while the (a) pretreatment composition is held. Contact.
From the viewpoint of cleaning performance, the interval from the completion of contact of the (a) pretreatment composition to the contact of the (b) posttreatment composition is preferably 30 seconds or more, and preferably 1 minute or more. More preferably, it is more preferably 5 minutes or more. From the viewpoint of effect and simplicity, 5 hours or less is preferable, 2 hours or less is more preferable, 1 hour or less is further preferable, and 30 minutes or less is particularly preferable.

In terms of cleaning performance, (b) physically, such as scraping with fingers, rubbing, rubbing with a brush, applying ultrasonic vibration, etc., until the post-treatment composition is brought into contact with the post-treatment composition. You may add some power. At that time, the pretreatment agent composition (a) is adjusted so as not to desorb more than necessary.

From the viewpoint of cleaning performance, it is preferable to contact the article to be cleaned with the post-treatment agent composition (b) by immersing the article to be washed in the post-treatment agent composition (b). Further, it is preferable to perform the dipping in a washing machine and stir.

[(A) Pretreatment Agent Composition] The (a) pretreatment agent composition used in the present invention is JIS in terms of detergency and safety.
K3362: pH of 20 ° C according to the method described in 1998
Is preferably 7.5 to 12, more preferably 8 to 11, still more preferably 8.5 to 11, particularly preferably 9 to 11, and most preferably 10 to 11.

The (a) pretreatment composition used in the present invention is
The viscosity at 20 ° C. is 1 to 50 mPa · s (B type viscometer, from the viewpoint of easy discharge from the container and easy contact with the object to be cleaned.
60 r / min), preferably 1 to 30 mPa · s, more preferably 1 to 20 mPa · s, and 2 to
15 mPa · s is particularly preferable.

<Component (a1)> The pretreatment composition (a) used in the present invention contains the component (a1) in an amount of 1 to 30% by mass. From the viewpoint of cleaning performance and contact property, it is preferably contained in 2 to 25% by mass, more preferably 3 to 20% by mass, and 3.5.
-15 mass% is more preferable, and 4-12 mass% is especially preferable.

The component (a1) has a molecular weight of preferably 1,000 or less, more preferably 800 or less, still more preferably 600 or less, from the viewpoint of cleaning performance.

From the viewpoint of detergency and environmental suitability, the amount of calcium captured by the component (a1) is 200 to 600 CaCO ₃ mg / g.
More preferably from _{250~550CaCO 3 mg / g, 300~500CaCO 3} mg / g is more preferable. Further, the calcium stability constant is preferably 4 to 10, more preferably 5 to 9, and further preferably 6 to 8,
6.5-8 is especially preferable.

In the present invention, the calcium stability constant and the amount of captured calcium are those determined by the following methods.

(Measurement Method of Calcium Stability Constant) 0.1 mol / liter NH ₄ Cl-NH ₄ O as a buffer solution
Prepare a H (pH 10) solution. Prepare all sample solutions using this buffer. An ion meter 920A manufactured by Orion Co., Ltd. and a Ca ²⁺ ion electrode are used to measure the Ca ²⁺ concentration. First, the relationship between the calcium chloride concentration and the potential of the electrode is obtained, and a calibration curve is created. 5.3 of calcium chloride
A 6 × 10 ⁻² mol / liter solution and a 5.36 × 10 ⁻⁴ mol / liter solution of the chelating agent sample are prepared. Add 1 ml of calcium chloride solution to 100 ml of chelating agent sample solution.
Add ml and stir for 5 minutes. The remaining Ca ²⁺ concentration is measured using a Ca ²⁺ ion electrode. The chelating agent is Ca
^The calcium stability constant (Ca stability constant) is calculated from the following formula, assuming that a chelate complex is formed with ^{2+ in a ratio} of 1: 1.

[0018]

[Equation 1]

(Measuring Method of Calcium Amount) Calcium amount (Ca amount) can be measured by the method described in JP-A-3-277696, page 3, lower right column, line 6 to page 4, upper left column, line 6 (however, (Anionic surfactant is replaced with chelating agent)).

As the component (a1), COOM in the molecule
A compound having 2 to 5, preferably 3 to 5, groups (M is H, Na, K, NH ₄ ) can be mentioned. Among them, the compounds represented by the following general formula (I) are preferable in terms of cleaning performance and environmental suitability.

[0021]

[Chemical 1]

[Wherein, R is — (CH ₂ ) _n —A, A is H, OH, COOM, and M is H, Na, K, N
H _4, preferably Na, n is a number of 0 to 5. ].

<Component (a2)> The pretreatment composition (a) used in the present invention contains water. From the viewpoint of cleaning performance and contact property, 50 to 95 mass% is preferable, 55 to 90 mass% is more preferable, 60 to 85 mass% is further preferable, and 65 to
80% by weight is particularly preferred.

<Other Components> (Surfactant) The pretreatment agent composition (a) used in the present invention preferably contains a surfactant in terms of cleaning performance and contact property, and is from 0.5 to 10 % Is more preferable, and 0.
5 to 8 mass% is more preferable, and 1 to 7 mass% is particularly preferable.

Examples of the surfactant (a) contained in the pretreatment composition include nonionic surfactants, anionic surfactants, cationic surfactants and amphoteric surfactants. Above all, it is preferable to contain an amphoteric surfactant from the viewpoint of cleaning performance, and 50% by mass or more of the surfactant, and further 6
It is preferably contained in an amount of 0 mass% or more, particularly 70 mass% or more.

Examples of the amphoteric surfactant include alkyl betaine, imidazolinium betaine, amine oxide and alkyl alanine. From the viewpoint of cleaning performance, the compound represented by the following general formula (II) or (III) is preferably 50% by mass or more, more preferably 60% by mass or more, and particularly preferably 70% by mass or more in the surfactant. The content of the compound represented by the general formula (II) in the surfactant is preferably 50% by mass or more, more preferably 60% by mass or more, and particularly preferably 70% by mass or more.

[0027]

[Chemical 2]

[Wherein R ¹ is an alkyl or alkenyl group having 7 to 20 carbon atoms, preferably 9 to 15 carbon atoms, and R ² and R ³ are each an alkyl group or alkenyl group having 1 to 3 carbon atoms, preferably carbon atoms It is an alkyl group of formula 1 or a hydrogen atom. R ⁴ is a hydrogen atom or an alkyl group or an alkenyl group having 1 to 5 carbon atoms, preferably a hydrogen atom or a methyl group,
m represents a number of 1 to 5, preferably 3. ]

[0029]

[Chemical 3]

[Wherein R ⁵ is an alkyl or alkenyl group having 8 to 20 carbon atoms, preferably 12 to 14 carbon atoms, R ⁶ and R ⁷
Are each an alkyl group or alkenyl group having 1 to 3 carbon atoms, preferably an alkyl group having 1 carbon atom or a hydrogen atom, p
Represents a number of 0 to 10, preferably 2 to 4. ].

As the anionic surfactant, a sulfuric acid ester salt of alcohol, a sulfuric acid ester salt of ethoxylate of alcohol, alkylbenzene sulfonate, paraffin sulfonate, α-olefin sulfonate, α
-Sulfo fatty acid salt, α-sulfo fatty acid alkyl ester salt or fatty acid salt. In particular, a linear alkylbenzene sulfonate in which the alkyl chain has 12 to 14 carbon atoms,
An alkyl sulfate ester salt having 12 to 18 carbon atoms is preferable, and as the counter ion, an alkali metal salt or an alkanolamine salt is preferable.

As the nonionic surfactant, polyoxyalkylene alkyl ether, polyoxyalkylene alkylphenyl ether, polyoxyalkylene sorbitan fatty acid ester, polyoxyalkylene glycol fatty acid ester, polyoxyethylene polyoxypropylene block polymer, fatty acid alkanolamide. , Alkyl polyglycosides and the like are preferable. Alkyl polyglycosides are particularly preferred.

Examples of cationic surfactants include quaternary mono long-chain alkyl or di long-chain alkyl ammonium salts.

In the present invention, the mass ratio of the component (a1), preferably the compound represented by the general formula (I), to the surfactant, preferably the amphoteric surfactant is such that the surfactant / (a
1) = 3/1 to 1/5 is preferable, 2/1 to 1/3 is more preferable, and 1/1 to 1 / is more preferable.
3, particularly preferably 1/1 to 1/2.

(Alkaline agent) The pretreatment composition (a) used in the present invention preferably contains an alkaline agent in view of cleaning performance and contact property, more preferably 1 to 30% by mass, 3 to 25 mass% is more preferable, and 5 to 2
0 mass% is especially preferable, and 5 to 15 mass% is the most preferable.

(A) Alkali agents contained in the pretreatment composition include, for example, alkali metal carbonates such as sodium carbonate, sodium hydrogen carbonate, potassium carbonate and potassium hydrogen carbonate, alkali metal salts such as sodium silicate and potassium silicate. Polyphosphates such as silicates, orthophosphates, metaphosphates, pyrophosphates, hexametaphosphates, alkanolamines such as monoethanolamine, diethanolamine, triethanolamine, disodium hydrogen phosphate, trisodium phosphate, Examples thereof include borate.

(A) The alkaline agent contained in the pretreatment composition has a maximum pH of 10 or more (20 ° C.) of 0.025 mass% aqueous solution or dispersion from the viewpoint of cleaning performance, and PH 9 for 1 liter of aqueous solution or dispersion
To obtain (20 ° C), add 0.1N hydrochloric acid solution to 10m
It is preferable that the compound is 1 or more. Such compounds include sodium carbonate, potassium carbonate,
Examples thereof include sodium silicate, trisodium phosphate, monoethanolamine and the like. Of these, sodium carbonate, potassium carbonate and sodium silicate are more preferable, and sodium carbonate is particularly preferable.

(Others) The pretreatment agent composition (a) used in the present invention preferably contains a hydrotrope agent, more preferably 1 to 30% by mass, from the viewpoint of stability at low temperature and contact property. Preferably, 2 to 15% by mass is more preferable, and 3 to 10% by mass is particularly preferable.

(A) As the hydrotrope agent contained in the pretreatment composition, a lower alcohol having 1 to 4 carbon atoms such as ethanol, methanol, propanol, glycerin, ethylene glycol, propylene glycol, or toluene sulfonic acid or its Examples thereof include salts, xylenesulfonic acid or salts thereof, compounds represented by the following general formula (IV), and the like.

X- (Ph) -O (CH ₂ CH ₂ O) _p (CH ₂ CHRO) _q Y (IV) [In the formula, X represents a hydrogen atom, an alkyl group or an alkenyl group having 1 to 4 carbon atoms, Hydroxyl group or halogen, Y
Is a hydrogen atom, a methyl group, or an ethyl group, and Ph
Is a phenylene group, R is a hydrogen atom, a methyl group,
Or an ethyl group, and p is 1 to 6, preferably 1 to
3, q is 0 to 4, preferably 0 to 2, p + q
Is 1 to 10, preferably 1 to 6. ].

Above all, a lower alcohol having 2 to 3 carbon atoms, p
-Toluenesulfonic acid or its salts are more preferred.

In addition to the (a) pretreatment composition of the present invention,
(1) Polyacrylic acid or its salt, polymaleic acid or its salt, carboxymethylcellulose, acrylic acid-maleic acid copolymer or its salt, maleic anhydride-diisobutylene copolymer or its salt, maleic anhydride-methyl vinyl ether Copolymer or salt thereof, maleic anhydride-isobutylene copolymer or salt thereof, maleic anhydride-vinyl acetate copolymer or salt thereof, and claims 1 to 21 (1) of JP-A-59-62614.
P. 3, col. 5 to p. 3, col. 4, line 14) Organic polyvalent carboxylic acids and / or salts thereof such as polymers 0.01 to 10
%, (2) 0.01 to 10% by weight of a redeposition preventing agent and a dispersant such as polyethylene glycol having an average molecular weight of 5,000 or more and a naphthalenesulfonate formalin condensate.
(3) Color transfer inhibitor 0.01 such as polyvinylpyrrolidone
10% by mass, (4) 0.01 to 2% by mass of foaming agent such as silicone and silica, (5) 0.01 to 200% of antioxidant such as butylhydroxytoluene, distyrenated cresol, sodium sulfite and sodium hydrogen sulfite. 2% by mass, (6) colorant, (7) amylase, protease,
Enzymes such as lipase and cellulase, (8) enzyme stabilizers such as calcium chloride, calcium sulfate, formic acid and boric acid (boron compound), (9) fragrances, (10) antibacterial preservatives and the like can be added.

[(B) Post-Treatment Agent Composition] The (b) post-treatment agent composition used in the present invention is JIS in terms of detergency and safety.
K3362: pH of 20 ° C according to the method described in 1998
Is preferably 7.5 to 12, more preferably 8 to 11, still more preferably 8.5 to 11, particularly preferably 9 to 11, and most preferably 10 to 11.

The (b) post-treatment agent composition used in the present invention is
Viscosity at 20 ° C is 0.5 in terms of ease of contact with the object to be cleaned.
~ 5 mPa · s (B type viscometer, 60 r / min) is preferable, 0.6 to 2 mPa · s is more preferable, and 0.8 to
1.5 mPa · s is more preferable.

<Component (b1)> The post-treatment composition (b) used in the present invention contains 0.005 to 0.2% by mass of a surfactant. 0.01-0.1 in terms of cleaning performance and contact
Mass% is preferable, and 0.015-0.05 mass% is more preferable.

As the component (b1), one or a combination of an anionic surfactant, a nonionic surfactant, an amphoteric surfactant and a cationic surfactant can be mentioned, preferably an anionic surfactant. Agents and nonionic surfactants. Particularly, in terms of detergency, the mass ratio of anionic surfactant / nonionic surfactant is preferably 20/1 to 1/10, more preferably 10/1 to 1/5, and 5/1 to 1
/ 1 is more preferable.

The anionic surfactant has 10 carbon atoms.
~ 18 sulfuric acid ester salt of alcohol, carbon number 8-20
Sulfate ester salts, alkylbenzene sulfonates, paraffin sulfonates, α-olefin sulfonates, α-sulfofatty acid salts, α-sulfofatty acid alkyl ester salts or fatty acid salts of alcohols of alcohols are preferred. Particularly in the present invention, the number of carbon atoms in the alkyl chain is 1.
0-14, preferably 12-14 linear alkyl benzene sulfonate is preferable, as the counter ion, alkali metal salts and amines are preferable, and sodium and / or
Alternatively, potassium, monoethanolamine and diethanolamine are preferable.

As the nonionic surfactant, polyoxyalkylene alkyl (C8-20) ether, alkyl polyglycoside, polyoxyalkylene alkyl (C8-20) phenyl ether, polyoxyalkylene sorbitan fatty acid (carbon number) 8-22) ester,
Polyoxyalkylene glycol fatty acid (C8 to C2
2) Ester and polyoxyethylene polyoxypropylene block polymer are preferable. In particular, as the nonionic surfactant, 4 to 20 mol of an alkylene oxide such as ethylene oxide (hereinafter referred to as EO) or propylene oxide (hereinafter referred to as PO) is added to an alcohol having 10 to 18 carbon atoms. Polyoxyalkylene alkyl ethers are preferable, and among them, HLB value (calculated by Griffin method) is 10.5 to 15.0, preferably 11.
Those of 0 to 14.5 are preferable.

<(B2) <(b2) Component> The (b) post-treatment agent composition used in the present invention contains water. 99-9 in terms of cleaning performance and contact
9.99 mass% is preferable, 99.5 to 99.98 mass% is more preferable, and 99.8 to 99.95 mass% is still more preferable.

<Other Components> The post-treatment composition (b) used in the present invention preferably contains an enzyme from the viewpoint of cleaning performance. Examples of the enzyme (b) contained in the post-treatment composition include amylase, protease, lipase, and cellulase. Of these, protease and cellulase are preferable.

The after-treatment composition (b) used in the present invention is
In terms of cleaning performance, (1) inorganic builder such as zeolite, amorphous aluminosilicate and crystalline silicate, (2) organic carboxylic acid polymer or its salt, (3) alkali such as carbonate and silicate Agent, (4) bleaching agent such as percarbonate and perborate, (5) bleaching activator, (6) anti-soil redeposition agent, (7) foam control agent, (8) perfume, (9) fluorescence enhancement Whitening agent, (1
0) A reducing agent or the like can be contained.

[0052]

EXAMPLES Examples 1 to 7 and Comparative Examples 1 to 3 (a) pretreatment composition having the composition shown in Table 1 was prepared. The pH of 20 ° C. of each of the obtained compositions of Examples was 10 to 1
It was 1. Further, the compositions of the examples all have a viscosity of 2 to
15mPa · s (B type viscometer, 20 ° C, 60r / mi
n).

Further, (b) post-treatment agent composition having the composition shown in Table 1 was prepared. P of the composition of the obtained example at 20 ° C.
All H were 10-11. Moreover, the viscosity of each of the compositions of the examples was 0.8 to 1.5 mPa · s (B-type viscometer, 20 ° C., 60 r / min).

With respect to these, the cleaning power was evaluated by the following method. The results are shown in Table 1.

<Evaluation of Detergency> JIS K3362: 1
On a piece of collar cloth as described in 998, 4 g of the pretreatment composition (a) was applied and left still for 5 minutes.

Next, an automatic two-tub type washing machine (Toshiba Galaxy 3.
40 L of (b) post-treatment agent composition was put in the washing tub of 6), and 1.4 kg of cotton unworn underwear, 0.6 kg of cotton /
6 non-worn polyester blended shirts and 6 pieces of collar cloth covered with (a) pretreatment composition
Put one) into the washing tub and wash normally for 10 minutes. Then 1
Dehydrate for 1 minute and rinse with running water for 8 minutes at a flow rate of 15 L / min. Then, it is dehydrated for 5 minutes and naturally dried in the room.

(A) A blank obtained by performing the same operation without applying the pretreatment composition is used as a blank, and a pair of eyes are visually compared to be evaluated according to the following criteria. The results are shown in Table 1.

Evaluation Criteria ⊚: The stains are clearly removed from the blanks in all three grades of stains. ◯: Stain is slightly removed from the blank in all of the three levels of stains. X: There is almost no difference from the blank in all the three levels of stains, or the stain removal is poor.

[0059]

[Table 1]

Amphoteric surfactant 1: lauramidopropyl
Amine oxide (Softofazoline LAO-C, Kawaken Phi
Chemical Co., Ltd., net amount equivalent) Amphoteric surfactant 2: dimethyllaurylamine oxai
De (Amphitor 20N, Kao Corporation, net content conversion) Amphoteric surfactant 3: lauryl (2-hydroxy-3-
Sulfopropyl) dimethyl betaine (Amphitol 20
HD, Kao Corporation, net conversion) ・ Nonionic surfactant 1: Decyl glucoside (Mido
Le 10, Kao Corporation, net conversion) -Nonionic surfactant 2: straight chain first having 10 to 14 carbon atoms
8 mol of EO and 2 mol of PO in the primary alcohol
The one with random addition -Nonionic surfactant 3: secondary alkane having 12 to 14 carbon atoms
An average of 6 moles of EO added to the call ・ Anionic surfactant 1: coconut oil fatty acid sodium salt -Anionic surfactant 2: straight chain alkane having 10 to 14 carbon atoms
Killbenzene sulfonate sodium ・ Anionic surfactant 3: α-ole having 14 to 18 carbon atoms
Potassium fin sulfonate -Chelating agent 1: Methylglycine diacetate trisodium
(Trilon M, BASF Japan Ltd., net conversion)
(Ca capture amount 430CaCO₃mg / g, Ca stability determination
(Number 6.1) -Chelating agent 2: aspartic acid-N, N-diacetic acid tetra sodium
Thorium (Ca capture amount 328CaCO₃mg / g, Ca
Stability constant 6.7) -Chelating agent 3: trisodium serine diacetate (Ca capture
Amount 347CaCO₃mg / g, Ca stability constant 6.5) -Chelating agent 4: tetrasodium glutamate diacetate (C
a Capture amount 305CaCO ₃mg / g, Ca stability constant
5.8) ・ Chelating agent 5: Ethylglycine diacetate trisodium
(Ca capture amount 419CaCO₃mg / g, Ca stability determination
(Number 5.7) -Carboxylic acid-based polymer: JP-A-10-60476
Phenoki synthesized by the method described on pages 116 to 13 of the report
Si polyethylene glycol, acrylic acid, maleic acid
Polymer (weight average molecular weight 10,000, solid content 51.2)
amount%) Enzyme: Evalase 16.0L-EX (protease,
(Novozymes) ・ Dye: coconut on orange (10ppm in the composition
(Mass ratio) addition)

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kazutoshi Ide             Kao Co., Ltd. 1334 Minato, Wakayama City, Wakayama Prefecture             Inside the laboratory (72) Inventor Hiroshi Nishimura             Kao Co., Ltd. 1334 Minato, Wakayama City, Wakayama Prefecture             Inside the laboratory F term (reference) 3B155 AA01 AA21 BB08 GA12 GA25                 4H003 AB03 AB15 AB19 AB44 AC05                       AC08 AC15 AC17 AC23 AD05                       BA12 DA01 DC02 EA16 EA28                       EB14 EB22 EB30 EC02 ED02                       ED28 FA04

Claims (6)

[Claims] 1. A chelating agent is used in an amount of 1 to 30% by mass of a material to be cleaned.
And (a) a pretreatment composition containing water, and then a (b) posttreatment composition containing 0.005 to 0.2% by mass of a surfactant and water. 2. The chelating agent of (a) the pretreatment composition comprises:
Calcium capture amount 200-600 CaCO ₃ mg / g and calcium stability constant 4-10, molecular weight 1000
The washing method according to claim 1, which is the following chelating agent. 3. The (a) pretreatment composition is a composition further containing 0.5 to 10% by mass of a surfactant and 1 to 30% by mass of an alkali agent. How to wash. 4. The washing method according to claim 1, wherein (b) the post-treatment composition is a composition further containing an enzyme. 5. The article to be cleaned is contacted with the pretreatment agent composition (a) by applying the pretreatment agent composition (a) to the article to be cleaned, and the article (b) is post-treated. The washing method according to any one of claims 1 to 4, wherein the contact with the composition is performed by immersing the article to be cleaned in (b) the post-treatment agent composition. 6. A step (a) of holding a pretreatment agent composition containing 1 to 30% by mass of a chelating agent and water in the article to be washed, and (a) an article to be washed holding the pretreatment agent composition. And (b) contacting with a post-treatment composition containing 0.005 to 0.2 mass% of a surfactant and water.