JP6284779B2 - Liquid detergent composition - Google Patents

Description

  The present invention relates to a liquid detergent composition. Specifically, the present invention relates to a liquid cleaning composition for food processing equipment and / or cooking equipment.

  Food processing factories regularly clean equipment and equipment used for food processing and / or cooking (ie, food processing equipment and / or cooking equipment) to ensure hygiene when production schedules are interrupted . Examples of equipment to be cleaned in a food processing factory include a net conveyor, a freezer, a slicer, and a rice mill. In addition, examples of the facility include a floor, a wall, and a work table. Since these objects to be cleaned are large in scale and complicated with parts, foam cleaning is usually applied to the object to be cleaned by foaming the cleaning agent as a method for efficient cleaning. Is adopted.

  In foam cleaning, a dilute solution obtained by diluting the cleaning composition with water is put into an injection device, and bubbles foamed by water pressure or air pressure are sprayed and adhered to the equipment or equipment to be cleaned and held for a certain period of time. Thereafter, a step of rinsing with water with or without rubbing with a brush or sponge is performed.

  In the foam cleaning, the foam has advantages in that it can easily check the cleaned part and the untreated part that is too much, and can suppress unnecessary scattering.

  Patent Document 1 discloses oxidizing halogen acids and salts thereof, amine oxide surfactants having one hydrocarbon group having 8 to 14 carbon atoms, fatty acids having 12 to 16 carbon atoms and salts thereof, and water. A liquid cleaning composition for food processing equipment and / or cooking equipment is disclosed.

JP 2012-149226 A

  The liquid detergent composition described in Patent Document 1 was excellent in foaming / foam stability during foam cleaning and foam breakage during rinsing. It has been desired to further improve the detergency against solid fat (hereinafter also referred to as room temperature solid fat) existing in a solid state at 20 ° C. without impairing long-term storage stability at low temperatures.

  The object of the present invention is to provide a liquid detergent composition having excellent foaming / foam stability during foaming cleaning and defoaming during rinsing, excellent detergency against room temperature solid fat, and excellent long-term low-temperature storage stability. To provide things.

  As a result of intensive studies on the above problems, the present inventors have identified six types of amine oxide having one hydrocarbon group having a specific number of carbon atoms and two types of fatty acids having a specific number of carbon atoms or salts thereof. It has been found that by containing it in a quantitative ratio, the detergency against room temperature solid fat is improved and it is excellent in long-term low-temperature storage stability, and the present invention has been completed.

The present invention
(A) Component: Amine oxide composed of the following components (a-1) to (a-6): 0.5% by mass or more, 18% by mass or less,
(A-1) Component: Amine oxide having one hydrocarbon group having 8 carbon atoms (a-2) Component: Amine oxide having one hydrocarbon group having 10 carbon atoms (a-3) Component: 12 carbon atoms Amine oxide (a-4) component having one hydrocarbon group: Amine oxide (a-5) component having one hydrocarbon group having 14 carbon atoms: Amine oxide having one hydrocarbon group having 16 carbon atoms (A-6) Component: Amine oxide having one hydrocarbon group having 18 carbon atoms (b) Component: Fatty acid consisting of the following components (b-1) and (b-2) or a salt thereof 0.5% by mass 10 mass% or less
(B-1) component: C12 fatty acid or salt thereof (b-2) component: C14 fatty acid or salt thereof and (c) component: containing water,
(A) The ratio of the sum total of (a-1) component and (a-2) component in a component is 5 mass% or more and 20 mass% or less,
The total proportion of the component (a-3) and the component (a-4) in the component (a) is 60% by mass or more and 80% by mass or less,
(A) The ratio of the sum total of (a-5) component and (a-6) component in a component is 10 mass% or more and 30 mass% or less,
PH at 25 ° C. is 13.3 or higher,
The present invention relates to a liquid detergent composition.

The present invention also relates to a foam cleaning method including the following steps 1 to 3.
Step 1: Step of diluting the liquid detergent composition of the present invention with water in advance and / or foaming it while being diluted and spraying it into a foam and attaching it to food processing equipment and / or cooking equipment Step 2 : A step of holding the foam for a certain period of time; and step 3: a step of rinsing the food processing equipment and / or cooking equipment to which the foam is attached with water.

  According to the present invention, the liquid detergent composition is excellent in foaming / foam stability during foaming cleaning and foam breakability during rinsing, excellent in cleaning power to room temperature solid fat, and excellent in long-term low-temperature storage stability. Things can be provided.

  The liquid detergent composition of the present invention contains the following components (a) to (c).

<(A) component>
The liquid detergent composition of the present invention comprises, as component (a), amine oxide having one hydrocarbon group having 8 carbon atoms as component (a-1), and hydrocarbon having 10 carbon atoms as component (a-2). An amine oxide having one group, an amine oxide having one hydrocarbon group having 12 carbon atoms as the component (a-3), an amine oxide having one hydrocarbon group having 14 carbon atoms as the component (a-4), (A-5) containing six amine oxides of component oxide (a-5) having one hydrocarbon group having 16 carbon atoms and component (a-6) having one hydrocarbon group having 18 carbon atoms .

  The component (a-1) is an amine oxide having one hydrocarbon group having 8 carbon atoms. Examples of the hydrocarbon group include an alkyl group and an alkenyl group, and an alkyl group is preferable. Specifically, as the component (a-1), for example, one hydrocarbon group having 8 carbon atoms and an alkyl group having 1 to 3 carbon atoms or a hydroxyalkyl group having 1 to 3 carbon atoms ( An amine oxide having two methyl groups is preferable. Examples of the component (a-1) include octyldimethylamine oxide.

  The component (a-2) is an amine oxide having one hydrocarbon group having 10 carbon atoms. Examples of the hydrocarbon group include an alkyl group and an alkenyl group, and an alkyl group is preferable. Specifically, as the component (a-2), for example, one hydrocarbon group having 10 carbon atoms and an alkyl group having 1 to 3 carbon atoms or a hydroxyalkyl group having 1 to 3 carbon atoms ( An amine oxide having two methyl groups is preferable. Examples of the component (a-2) include decyldimethylamine oxide.

  The component (a-3) is an amine oxide having one hydrocarbon group having 12 carbon atoms. Examples of the hydrocarbon group include an alkyl group and an alkenyl group, and an alkyl group is preferable. Specifically, as the component (a-3), for example, one hydrocarbon group having 12 carbon atoms and an alkyl group having 1 to 3 carbon atoms or a hydroxyalkyl group having 1 to 3 carbon atoms ( An amine oxide having two methyl groups is preferable. Examples of the component (a-3) include dodecyldimethylamine oxide.

  The component (a-4) is an amine oxide having one hydrocarbon group having 14 carbon atoms. Examples of the hydrocarbon group include an alkyl group and an alkenyl group, and an alkyl group is preferable. Specifically, as the component (a-4), for example, one hydrocarbon group having 14 carbon atoms and an alkyl group having 1 to 3 carbon atoms or a hydroxyalkyl group having 1 to 3 carbon atoms ( An amine oxide having two methyl groups is preferable. Examples of the component (a-4) include tetradecyldimethylamine oxide.

  The component (a-5) is an amine oxide having one hydrocarbon group having 16 carbon atoms. Examples of the hydrocarbon group include an alkyl group and an alkenyl group, and an alkyl group is preferable. Specifically, as the component (a-5), for example, one hydrocarbon group having 16 carbon atoms and an alkyl group having 1 to 3 carbon atoms or a hydroxyalkyl group having 1 to 3 carbon atoms ( An amine oxide having two methyl groups is preferable. Examples of the component (a-5) include hexadecyldimethylamine oxide.

  The component (a-6) is an amine oxide having one hydrocarbon group having 18 carbon atoms. Examples of the hydrocarbon group include an alkyl group and an alkenyl group, and an alkyl group is preferable. Specifically, as the component (a-6), for example, one hydrocarbon group having 18 carbon atoms and an alkyl group having 1 to 3 carbon atoms or a hydroxyalkyl group having 1 to 3 carbon atoms ( An amine oxide having two methyl groups is preferable. Examples of the component (a-6) include octadecyldimethylamine oxide.

  The components (a-1) to (a-6) may be commercially available products or synthetic products, respectively. Moreover, if the ratio of each component mentioned later is satisfy | filled, you may use the mixture containing each component for preparation of a composition.

  In the liquid detergent composition of the present invention, the total proportion of the component (a-1) and the component (a-2) in the component (a) is preferably 5% by mass or more from the viewpoint of long-term low-temperature storage stability. Is 8% by mass or more, and from the viewpoint of detergency to room temperature solid fat, it is 20% by mass or less, preferably 16% by mass or less, more preferably 12% by mass or less.

  In the liquid detergent composition of the present invention, the total proportion of the component (a-3) and the component (a-4) in the component (a) is 60 from the viewpoint of foamability / foam stability during foaming. From the viewpoint of detergency of room temperature solid fat, it is 80% by mass or less, preferably 75% by mass or less, more preferably 70% by mass or less.

  In the liquid detergent composition of the present invention, the total proportion of the component (a-5) and the component (a-6) in the component (a) is 10% by mass or more from the viewpoint of detergency with respect to room temperature solid fat, It is preferably 14% by mass or more, more preferably 18% by mass or more, and from the viewpoint of long-term low-temperature storage stability, it is 30% by mass or less, preferably 25% by mass or less.

  In the liquid cleaning composition of the present invention, the mass ratio of the component (a-4) / (a-1) is preferably 1 or more, more preferably 2 from the viewpoint of foamability / foam stability during foaming. From the viewpoint of low temperature stability, it is preferably 8 or less, more preferably 7 or less, more preferably 6 or less.

  In the liquid cleaning composition of the present invention, the mass ratio of the component (a-4) / (a-3) is preferably 0.2 or more, more preferably from the viewpoint of foamability / foam stability during foaming. From the viewpoint of low temperature stability, it is preferably 0.6 or less, more preferably 0.5 or less.

  In the liquid detergent composition of the present invention, the content of the component (a) is 0.5% by mass or more, preferably 1% by mass or more, more preferably 2% by mass or more, from the viewpoint of detergency with respect to room temperature solid fat. More preferably 3% by mass or more, and from the viewpoint of long-term low-temperature storage stability, 18% by mass or less, preferably 15% by mass or less, more preferably 10% by mass or less, more preferably 8% by mass or less. It is.

<(B) component>
The component (b) is a fatty acid consisting of the following components (b-1) and (b-2) or a salt thereof.
(B-1) Component: C12 fatty acid or salt thereof (b-2) Component: C14 fatty acid or salt thereof Examples of the salt include alkali metal salts, preferably sodium salts Or a potassium salt, More preferably, it is a sodium salt. (B-1) As a component, lauric acid or its salt is mentioned. Moreover, myristic acid or its salt is mentioned as (b-2) component.

  In the liquid detergent composition of the present invention, the content of the component (b) is 0.5% by mass or more, preferably 0.8% by mass or more, more preferably 1. From the viewpoint of long-term low-temperature storage stability, it is 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less. Here, the said content is a value which used the conversion amount as a fatty acid, when a fatty acid salt is contained in (b) component.

  In the liquid detergent composition of the present invention, the mass ratio of the component (b-1) / (b-2) is preferably 1 or more, more preferably 1.5 or more, from the viewpoint of long-term low-temperature storage stability. Yes, more preferably 2 or more, still more preferably 2.5 or more, and from the viewpoint of foaming properties during rinsing, it is preferably 20 or less, more preferably 10 or less, and even more preferably 5 or less. Here, the said mass ratio is a value which used the conversion amount as a fatty acid, when a fatty acid salt is contained in (b) component.

  In the liquid detergent composition of the present invention, the mass ratio of component (a) / component (b) is preferably 1 or more, more preferably 1.3 or more, and still more preferably 1.5. And it is preferably 10 or less, more preferably 6 or less, and still more preferably 4 or less.

<(C) component>
The liquid detergent composition of the present invention contains water as the component (c). The water is preferably ion-exchanged water containing no hardness component. Also, purified water is preferred.

<(D) component>
The liquid detergent composition of the present invention can contain the following component (d) within the range not performing the effects of the present invention.
Component (d): one or more compounds selected from oxidative halogen acids and their salts

  Examples of the oxidizing halogen acid (d) include hypochlorous acid, hypobromite, and chlorous acid, and hypochlorous acid is preferred from the viewpoint of bactericidal properties. Examples of the oxidative halogen acid salt include hypochlorous acid, hypobromite, and alkali metal salts of chlorous acid. From the viewpoint of bactericidal properties and versatility, alkali metal salts of hypochlorous acid are used. Of these, sodium hypochlorite is preferable.

  The content of the component (d) is preferably 0.5% by mass or more, more preferably 1% by mass or more, more preferably 2% by mass or more in the composition from the viewpoint of a sufficient bactericidal effect, and From the viewpoint of the feeling of use, in the composition, it is preferably 10% by mass or less, more preferably 7% by mass or less, and more preferably 4% by mass or less. Here, the content is a value using a converted amount as an oxidizing halogen acid when the component (d) contains an oxidizing halogen acid salt.

<(E) component>
The liquid detergent composition of the present invention is preferably strongly alkaline from the viewpoint of detergency. The liquid detergent composition of the present invention may further contain the following component (e) within the range not performing the effects of the present invention.
(E) Component: Alkaline agent

  Examples of the alkali agent of component (e) include alkali agents selected from alkali metal hydroxides and alkali metal silicates. Examples of the alkali metal hydroxide include sodium hydroxide and potassium hydroxide. Examples of the alkali metal silicate include sodium silicate and potassium silicate, specifically, sodium metasilicate, sodium orthosilicate, and No. 1 silicic acid. Sodium, No. 2 sodium silicate, No. 3 sodium silicate, No. 4 sodium silicate, 1K potassium silicate, and 2K potassium silicate are mentioned.

  The content of the component (e) is preferably such that the liquid detergent composition of the present invention has a pH at 25 ° C. of 13.3 or higher, preferably 13.4 or higher, more preferably 13.5 or higher. Further, the amount may be 13.6 or more, 13.7 or more, and further 13.8 or more. The specific content of the component (e) is preferably 1% by mass or more, more preferably 3% by mass or more, more preferably 5% by mass or more from the viewpoint of detergency, and safety during use. From this viewpoint, it is preferably 20% by mass or less, more preferably 15% by mass or less, and more preferably 10% by mass or less.

  Furthermore, the liquid detergent composition of the present invention is not limited to the desired effect of the present application, and other surfactants, chelating agents, and the like that are usually used in liquid detergent compositions for food processing equipment and / or cooking equipment, You may contain arbitrary components, such as a foaming agent, a hydrotrope agent, a coloring agent, a fragrance | flavor, a builder, a rust preventive agent, and a viscosity modifier (for example, diisobutylene / maleic acid copolymer).

  The liquid detergent composition of the present invention has a pH at 25 ° C. of 13.3 or higher, preferably 13.4 or higher, more preferably 13.5 or higher. Further, it may be 13.6 or more, further 13.7 or more, and further 13.8 or more. Here, the pH value is a value measured using pH METER F-21 (manufactured by Horiba, Ltd.).

  The liquid detergent composition of the present invention is suitable for food processing equipment and / or cooking equipment. In the present invention, the term “food processing equipment and / or cooking equipment” may mean equipment and equipment used when processing and / or cooking food in a food processing factory. Examples of such equipment include a net conveyor, a freezer, a slicer, and a rice mill. Examples of such facilities include a floor, a wall, and a work table. In the present invention, the term “a liquid detergent composition for food processing equipment and / or cooking equipment” means a liquid detergent composition for use in washing the above “food processing equipment and / or cooking equipment”. More specifically, it may mean a liquid detergent composition for cleaning the above “food processing equipment and / or cooking equipment” by foam cleaning.

<Washing method of food processing equipment and / or cooking equipment>
The liquid cleaning composition of this invention is used suitably for the washing | cleaning method containing the following processes 1-3.
Step 1: The liquid detergent composition of the present invention is preliminarily diluted and / or diluted with water, preferably at a dilution ratio of 2 times or more, more preferably 5 times or more, and preferably 200 times or less. However, it is foamed and sprayed in the form of foam and attached to food processing equipment and / or cooking equipment Step 2: Step of holding foam for a certain period of time, and Step 3: Food processing equipment with foam attached and / or Rinsing cooking equipment with water

  In Step 1, the liquid detergent composition of the present invention is preliminarily diluted with water, preferably at a dilution ratio of 2 or more and 200 or less, and then sprayed in the form of foam. Alternatively, the liquid detergent composition of the present invention is put in a dedicated container, directly connected to a water supply by a hose or the like, and mixed while being diluted and sprayed into a foam. The diluted solution of the liquid detergent composition of the present invention can be jetted in a foam form by combining the above pre-dilution and simultaneous dilution. The dilution ratio in step 1 is preferably 2 times or more, more preferably 5 times or more, more preferably 20 times or more, and preferably 200 times or less, more preferably 100 times or less.

  Here, the water used for dilution is generally assumed to be water containing a hardness component such as tap water. The hardness of water used for dilution is preferably in the range of 0.1 ° dH or more and 30 ° dH or less from the viewpoint of foam stability during foam cleaning. Preferably it is 20 degrees dH or less, More preferably, it is 15 degrees dH or less, More preferably, it is 12 degrees dH or less, More preferably, it is 8 degrees dH or less, More preferably, it is the range of 4 degrees dH or less.

  As an aspect in which the diluted solution of the liquid detergent composition of the present invention is jetted in the form of foam, an appropriate amount of the diluted solution diluted with water at a predetermined magnification is filled in a dedicated foam washer and air / compressed from the outside. The aspect which mixes air and injects in foamy form is mentioned suitably. If the processing area is large, such as a production line in a food processing factory, a bubble washer (for example, “SCU-HF” manufactured by Spraying, “KF-100”, “KF-200” manufactured by Kao Corporation) Preferably used. When the processing area is small, such as a cooking utensil such as a cutting board, a hand sprayer that can generate bubbles intermittently, such as a trigger sprayer or a former player, is preferably used.

  In step 1, it is preferable to spray the diluted solution of the liquid detergent composition of the present invention in the form of foam without intermittent. Here, “injection without interruption” means that the cleaning agent is continuously injected in a foam form (for example, 5 seconds or more) while being opened by a lever, switch, or the like using a foam washer. This is an "intermittent" injection, for example, an injection that occurs when a lever is pulled using a hand sprayer such as a trigger sprayer or a former player, and stops immediately. Distinguish from the aspect.

  The mode of spraying in a foam form without using a foam washer is more effective when the area or scale of the food processing equipment and / or cooking equipment to be cleaned is large.

  When using a foam washer, the expansion ratio (ratio of foam volume (mL) / foam mass (g)) is preferably 3 times or more, more preferably 5 times or more, more preferably 10 times or more, And it is preferably 50 times or less, more preferably 40 times or less. The pressure during injection (gauge pressure) is preferably 0.1 MPa or more, more preferably 0.2 MPa or more, and preferably 1 MPa or less, more preferably 0.8 MPa or less, more preferably 0.5 MPa. The following is preferable. When using a hand sprayer such as a trigger sprayer or a foam player, the expansion ratio is preferably 2 times or more, more preferably 3 times or more, and preferably 30 times or less, more preferably 20 times or less, More preferably, it is 10 times or less.

  In Step 1, the diluted solution of the liquid detergent composition of the present invention is jetted in the form of foam and attached to food processing equipment and / or cooking equipment, and then the foam is held for a certain time (Step 2). The time for holding the foam in step 2 is preferably 1 minute or more, and preferably 60 minutes or less, more preferably 45 minutes or less, more preferably 30 minutes or less, from the viewpoint of the mechanism and workability of each device. More preferably, it is 20 minutes or less, More preferably, it is 15 minutes or less, More preferably, it is 10 minutes or less, More preferably, it is 5 minutes or less. In addition, from the viewpoint of detergency, the time for holding the bubbles in step 2 is preferably 1 minute or more, more preferably 5 minutes or more, more preferably 10 minutes or more, more preferably 15 minutes or more, more preferably 20 minutes. More preferably, it is 60 minutes or less, more preferably 45 minutes or less, more preferably 30 minutes or less.

  The time for holding the bubbles in step 2 varies depending on the dilution ratio of the diluted solution and the usage scene, and is not particularly limited. For example, it is 2 times or more and less than 50 times (preferably 5 times or more and less than 50 times). At the dilution ratio, the time for holding the bubbles is preferably 1 minute or more and 60 minutes or less. Moreover, it is preferable to hold | maintain a bubble stably for 1 minute or more and 10 minutes or less in the dilution rate of 50 times or more and 200 times or less.

  While it is preferable to leave the foam in Step 2 while it is held, it is possible to add a little water or the like.

  After holding the foam for a certain period of time, in step 3, the food processing equipment and / or cooking equipment to which the foam has been attached is rinsed with water. The temperature of the rinsing water is preferably 10 ° C. or higher, more preferably 20 ° C. or higher, and preferably 70 ° C. or lower.

Examples 1-3 and Comparative Examples 1-4
The liquid detergent composition shown in Table 1 was prepared and the following tests were conducted. The results are also shown in Table 1. The compositions of the examples in Table 1 are suitable for food processing equipment and / or cooking equipment.

(1) Detergency test About 20 mg of minced meat mixed with beef: pork = 1: 1 is attached to a standard test plate (SUS304: 1.0 mm x 30 mm x 80 mm manufactured by Nippon Test Panel Co., Ltd.) and left overnight. This was used as a cleaning model test plate. 90mL of liquid detergent composition 3.3 mass% aqueous solution (4 ° dH hard water, 30 times diluted) is put into a pump former container (B523: manufactured by Yoshino Kogyo Co., Ltd.) and formed by pushing the former head 2 times. The foam (produced 1 g of foam per push; foaming ratio 30 times) was applied to the washed model test plate. After 10 minutes of application, the sample was rinsed with tap water, dried, the mass of the test piece was measured, and the cleaning rate (%) was calculated according to the following formula.
Cleaning rate (%) = 100 × [(Amount of adhered minced meat) − (Amount of residual minced meat oil)] / (Amount of adhered minced meat)

(2) Long-term storage stability test The liquid detergent composition described in Table 1 was stored in an environment of -5 ° C for 20 days. If it was a transparent liquid at −5 ° C., it was judged as acceptable (◯). On the other hand, what was phase-separated was described as "separation".

  In Table 1, the mass% of the component (d) is mass% using the converted amount as the oxidizing halogen acid, and the numerical value in parentheses is the mass% as the oxidizing halogen acid salt.

* Diisobutylene / maleic acid copolymer: Demol EP, manufactured by Kao Corporation

  In Table 1, the compositions according to the examples were also excellent in foaming property / foam stability during foam cleaning and foam breakability during rinsing.

Claims (6)

(A) Component: Amine oxide composed of the following components (a-1) to (a-6): 2% by mass or more, 18% by mass or less,
(A-1) Component: Amine oxide having one hydrocarbon group having 8 carbon atoms (a-2) Component: Amine oxide having one hydrocarbon group having 10 carbon atoms (a-3) Component: 12 carbon atoms Amine oxide (a-4) component having one hydrocarbon group: Amine oxide (a-5) component having one hydrocarbon group having 14 carbon atoms: Amine oxide having one hydrocarbon group having 16 carbon atoms (A-6) Component: Amine oxide having one hydrocarbon group having 18 carbon atoms (b) Component: Fatty acid consisting of the following components (b-1) and (b-2) or a salt thereof 0.5% by mass 10 mass% or less
(B-1) component: C12 fatty acid or salt thereof (b-2) component: C14 fatty acid or salt thereof and (c) component: containing water,
(A) The ratio of the sum total of (a-1) component and (a-2) component in a component is 5 mass% or more and 20 mass% or less,
The total proportion of the component (a-3) and the component (a-4) in the component (a) is 60% by mass or more and 80% by mass or less,
(A) The ratio of the sum total of (a-5) component and (a-6) component in a component is 10 mass% or more and 30 mass% or less,
PH at 25 ° C. is 13.3 or higher,
Liquid detergent composition. Furthermore, the liquid cleaning composition of Claim 1 which contains the following (d) component 0.5 mass% or more and 10 mass% or less.
Component (d): one or more compounds selected from oxidative halogen acids and their salts Furthermore, the liquid cleaning composition of Claim 1 or 2 containing the following (e) component.
(E) Component: Alkaline agent   The liquid detergent composition according to any one of claims 1 to 3, which is used for food processing equipment and / or cooking equipment. A foam cleaning method comprising the following steps 1 to 3.
Step 1: The liquid detergent composition according to any one of claims 1 to 4 is pre-diluted with water and / or foamed and jetted into a foam while diluting the food processing equipment and / or Or the process of making it adhere to cooking equipment Step 2: The process of holding foam for a certain period of time, and the process 3: The process of rinsing the food processing equipment and / or cooking equipment to which foam was made to adhere   6. The foam cleaning method according to claim 5, wherein in step 1, the liquid cleaning composition is diluted in advance with water at a dilution ratio of 2 to 200 times and sprayed while being diluted.