JP7849016B2 - Kitchen sponge - Google Patents

Description

This invention relates to a kitchen sponge.

Conventionally, there are kitchen sponges made by laminating multiple layers (for example, Patent Document 1).

Japanese Patent Publication No. 2003-521

However, conventional technology still had room for improvement in achieving both effective dirt removal and minimal scratching of objects being washed, such as dishes.

This invention aims to solve the aforementioned problems and provide a kitchen sponge that better balances dirt-removing ability and scratch resistance.

[1] The base layer,
An intermediate layer formed on the first side of the stacking direction of the base layer,
A surface layer formed on the first side of the intermediate layer in the stacking direction,
A kitchen sponge equipped with,
The base layer, the intermediate layer, and the surface layer are each made of urethane foam.
The aforementioned surface layer is a compressed and molded product of urethane foam.
A kitchen sponge in which, while the kitchen sponge is pressed from the first side in the stacking direction at a speed of 50 mm/min with the second side of the kitchen sponge in contact with a fixed plane, the compressive load when the compressive strain reaches 5.6% is 10.0 N or more.
This allows for a better balance between dirt-removing properties and scratch resistance.

[2] The kitchen sponge according to [1], wherein the kitchen sponge is pressed from the first side in the stacking direction at a speed of 50 mm/min while the second side of the kitchen sponge in the stacking direction is in contact with a fixed plane, and the compressive strain when the compressive load becomes 8.6 N is 5.0% or less.
This further improves the dirt-removing ability.

[3] The kitchen sponge according to [1] or [2], wherein, while the kitchen sponge is pressed from the first side in the stacking direction at a speed of 50 mm/min with the second side of the kitchen sponge in contact with a fixed plane, the compressive load when the compressive strain reaches 40.6% is 35.0 N or more, and the difference between the minimum and maximum compressive loads within the range of 40.6% to 50.3% compressive strain is 5.0 N or less.
This further improves the dirt-removing ability.

[4] The kitchen sponge according to any one of [1] to [3], wherein the maximum value of the compressive load measured while the kitchen sponge is pressed from the first side in the stacking direction at a speed of 50 mm/min with the second side of the kitchen sponge in contact with a fixed plane until the compressive strain reaches a maximum of 75.1%, is 200 N or more.
This further improves the dirt-removing ability.

[5] The kitchen sponge according to any one of [1] to [4], wherein the Asker F hardness of the surface layer is 55 to 88.
This allows for an even better balance between dirt-removing properties and scratch resistance.

[6] The kitchen sponge according to any one of [1] to [5], wherein the thickness of the surface layer is 6 mm or less.
This allows for an even better balance between dirt-removing properties and scratch resistance.

[7] The thickness of the intermediate layer is 2 to 4 times the thickness of the surface layer.
The kitchen sponge according to any one of [1] to [6], wherein the thickness of the base layer is 3.5 to 7 times the thickness of the surface layer.
This allows for an even better balance between dirt-removing properties and scratch resistance.

This invention provides a kitchen sponge that better balances dirt-removing ability with resistance to scratching.

This is a schematic perspective view of a kitchen sponge according to one embodiment of the present invention. This diagram shows the experimental results of kitchen sponges according to the examples and comparative examples. This diagram shows the experimental results of kitchen sponges according to the examples and comparative examples. This diagram shows the experimental results of kitchen sponges according to the examples and comparative examples.

The kitchen sponge according to the present invention is suitable for use in cleaning kitchen items such as dishes and cooking utensils.
The following describes an embodiment of the kitchen sponge according to this invention with reference to the drawings.

Figure 1 schematically shows a kitchen sponge LB according to one embodiment of the present invention.
Kitchen sponge LB comprises a base layer L3, an intermediate layer L2, and a surface layer L1. The kitchen sponge LB of this embodiment has a three-layer structure in which these three layers are stacked.
In this specification, as shown in Figure 1, the direction in which the base layer L3, intermediate layer L2, and surface layer L1 are laminated is referred to as the "lamination direction X" of the kitchen sponge LB. Furthermore, one side in the lamination direction X is referred to as the "first lamination direction side X1," and the other side in the lamination direction X is referred to as the "second lamination direction side X2."
The intermediate layer L2 is formed on the surface L3a of the base layer L3 on the first side X1 in the stacking direction. The surface layer L1 is formed on the surface L2a of the intermediate layer L2 on the first side X1 in the stacking direction.

In this embodiment, the base layer L3, the intermediate layer L2, and the surface layer L1 are fixed to each other.
For example, the base layer L3, the intermediate layer L2, and the surface layer L1 may be bonded to each other via an adhesive. Any adhesive can be used; for example, a urethane-based adhesive can be used. Urethane-based adhesives have good compatibility and penetrate into the framework of each layer, resulting in strong adhesion.
Alternatively, the base layer L3, the intermediate layer L2, and the surface layer L1 may be fixed to each other by heat welding or the like, without the use of an adhesive.

The base layer L3, the intermediate layer L2, and the surface layer L1 are each made of urethane foam.
The surface layer L1 is a compressed and molded product of urethane foam. Preferably, the surface layer L1 is a compressed and molded product of flexible polyurethane foam.
Here, a "compression-formed product" of polyurethane foam refers to a molded product obtained by pressing polyurethane foam by applying heat and pressure (compression molding). Compression molding of polyurethane foam imparts permanent deformation to the polyurethane foam itself, resulting in an increase in volume density and hardness. Therefore, a compression-formed product of polyurethane foam that has undergone permanent deformation is extremely superior in terms of strength, oil resistance, and solvent resistance.
In this embodiment, since the surface layer L1 is a compressed and molded product of urethane foam, it can have effective dirt-scraping properties (dirt-scraping ability) against dirt adhering to the surface of the object to be cleaned.
If the surface layer L1 is made from an uncompressed urethane foam product (i.e., urethane foam that has not undergone compression molding), it may be difficult to obtain sufficient dirt-removing properties. Also, if the surface layer L1 is made from a nonwoven fabric containing an abrasive, it may easily scratch the object being cleaned (i.e., it may be difficult to obtain sufficient scratch resistance).

It is preferable that both the intermediate layer L2 and the base layer L3 are non-compression molded products.

The following describes preferred values for various measurements obtained by performing a compression test on kitchen sponge LB using a compression testing device.
Herein, in this specification, "compression testing device" refers to the AGS-J 5kN manufactured by Shimadzu Corporation. Although not shown in the figures, the compression testing device comprises a support base and a pressure plate located above the support base. In a compression test of kitchen sponge LB using the compression testing device, the kitchen sponge LB is placed on the upper surface of the support base and compressed from above by the pressure plate. While the kitchen sponge LB is being compressed, the compression testing device measures the compressive load acting on the kitchen sponge LB by the pressure plate at predetermined time intervals (0.3 seconds).
In all compression tests described herein, the kitchen sponge LB is pressed (and thus compressed) while displacing the pressure plate in the stacking direction X at a speed of 50 mm/min until the compressive strain of the kitchen sponge LB reaches a maximum of 75.1%, and the compressive load during this time is measured.
Here, the "compression strain" (%) of kitchen sponge LB refers to the ratio (λ × 100 / L) (%) of the length by which kitchen sponge LB has shrunk due to compression (i.e., the displacement length of the pressure plate) λ (mm) to the thickness (length in the lamination direction X) L (mm) of kitchen sponge LB before compression.
In compression tests, the compressive load generally tends to increase as the compressive strain increases. However, while the compressive strain gradually increases, the compressive load may fluctuate slightly up or down due to measurement errors and other factors.

In a compression test using a compression testing device, the maximum value of the compressive load measured while pressing the kitchen sponge LB from the first side X1 in the stacking direction at a speed of 50 mm/min with the surface LBb on the second side X2 in the stacking direction of the kitchen sponge LB in contact with a fixed plane until the compressive strain reaches a maximum of 75.1% is preferably 200 N or more, more preferably 230 N or more, and even more preferably 240 N or more. As a result, the hardness of the portion of the kitchen sponge LB on the first side X1 in the stacking direction is sufficiently hard when the compressive strain is around 75.1%, so the dirt-scraping ability (especially the dirt-scraping ability against relatively fine dirt (specifically, dirt with a particle size of 100 μm or less (especially 10 to 70 μm)) can be improved when the user rubs the object to be cleaned with strong force using the surface LBa (in this embodiment, the surface L1a on the first side X1 in the stacking direction of the surface layer L1) of the kitchen sponge LB.
In a compression test using a compression testing device, the maximum value of the compressive load measured while pressing the kitchen sponge LB from the first side X1 in the stacking direction at a speed of 50 mm/min with the surface LBb on the second side X2 in the stacking direction of the kitchen sponge LB in contact with a fixed plane until the compressive strain reaches a maximum of 75.1% is preferably 350 N or less, more preferably 300 N or less, even more preferably 270 N or less, and even more preferably 250 N or less. As a result, the hardness of the portion of the kitchen sponge LB on the first side X1 in the stacking direction is not too hard when the compressive strain is near 75.1%, which improves the resistance to scratching the object being cleaned when the user rubs the object being cleaned with strong force using the surface LBa (in this embodiment, the surface L1a on the first side X1 in the stacking direction of the surface layer L1) of the kitchen sponge LB on the object being cleaned.
Therefore, by setting the range of the compressive load as described above, it is possible to achieve a better balance between dirt removal and resistance to scratching.
Here, "the state in which the surface LBb on the second side X2 of the stacking direction of the kitchen sponge LB is in contact with the fixed plane" means that the kitchen sponge LB is oriented so that the surface LBb faces downwards, and the surface LBb is in contact with the fixed plane (i.e., the upper surface of the support stand of the compression test device).
Furthermore, "pressing the kitchen sponge LB from the first side X1 in the stacking direction" means that the pressure plate of the compression testing device is in contact with the surface LBa of the kitchen sponge LB on the first side X1 in the stacking direction, and then displaced downwards (from the first side X1 in the stacking direction towards the second side X2 in the stacking direction), thereby pressing the kitchen sponge LB from the first side X1 in the stacking direction with the pressure plate.
Furthermore, "compression load" refers to the compression load measured by a compression testing device.
Furthermore, the "compressive load measured while pressing the kitchen sponge LB from the first side X1 in the stacking direction at a speed of 50 mm/min with the surface LBb on the second side X2 in the stacking direction of the kitchen sponge LB in contact with a fixed plane until the compressive strain reaches a maximum of 75.1%" typically takes its maximum value when the compressive strain is close to 75.1%.

In a compression test using a compression testing device, the maximum value of the compressive load measured while the kitchen sponge LB is pressed from the second side X2 in the stacking direction at a speed of 50 mm/min with the surface LBa on the first side X1 in the stacking direction of the kitchen sponge LB in contact with a fixed plane until the compressive strain reaches a maximum of 75.1% is preferably 340 N or less, more preferably 320 N or less, and even more preferably 300 N or less. As a result, when the compressive strain is near 75.1%, the hardness of the portion of the kitchen sponge LB on the second side X2 in the stacking direction is sufficiently soft, so when a user holds the kitchen sponge LB from the second side X2 in the stacking direction, the kitchen sponge LB becomes more comfortable to hold, the load on the hand is reduced, and the user's perceived usability is improved.
Here, "the state in which the surface LBa on the first side X1 in the stacking direction of the kitchen sponge LB is in contact with the fixed plane" means that the kitchen sponge LB is oriented so that the surface LBa faces downwards, and the surface LBa is in contact with the fixed plane (i.e., the upper surface of the support stand of the compression test device).
Furthermore, "pressing the kitchen sponge LB from the second side X2 in the stacking direction" means that the pressure plate of the compression testing device is in contact with the surface LBb of the kitchen sponge LB on the second side X2 in the stacking direction, and then displaced downwards (from the second side X2 in the stacking direction toward the first side X1 in the stacking direction), thereby pressing the kitchen sponge LB from the second side X2 in the stacking direction with the pressure plate.
Furthermore, the "compressive load measured while pressing the kitchen sponge LB from the second side X2 in the stacking direction at a speed of 50 mm/min with the surface LBa on the first side X1 in the stacking direction of the kitchen sponge LB in contact with a fixed plane until the compressive strain reaches a maximum of 75.1%" typically takes its maximum value when the compressive strain is close to 75.1%.

In a compression test using a compression testing device, the maximum value of the compressive load measured while the kitchen sponge LB is pressed from the second side X2 in the stacking direction at a speed of 50 mm/min with the surface LBa on the first side X1 in the stacking direction of the kitchen sponge LB in contact with a fixed plane until the compressive strain reaches a maximum of 75.1% is preferably 200 N or more, more preferably 250 N or more, and even more preferably 280 N or more. This ensures that the hardness of the portion of the kitchen sponge LB on the second side X2 in the stacking direction is not too soft when the compressive strain is near 75.1%, thereby improving the user's feel when holding the kitchen sponge LB from the second side X2 in the stacking direction.

In a compression test using a compression testing device, the kitchen sponge LB is preferably subjected to a compression load of 15.0 N or more, and more preferably 17.0 N or more, when the compression strain reaches 6.5% while the kitchen sponge LB is pressed from the first side X1 in the stacking direction at a speed of 50 mm/min with the surface LBb on the second side X2 in the stacking direction of the kitchen sponge LB in contact with a fixed plane. This increases the hardness of the portion of the kitchen sponge LB on the first side X1 in the stacking direction when the compression strain is 6.5%, thereby improving the dirt-scraping ability (especially for relatively fine dirt (specifically, dirt with a particle size of 100 μm or less (especially 10 to 70 μm)) when the user rubs the object to be cleaned with a soft touch (weak force) using the surface LBa (in this embodiment, the surface L1a on the first side X1 in the stacking direction of the surface layer L1) of the kitchen sponge LB.
Furthermore, in a compression test using a compression testing device, while the kitchen sponge LB is pressed from the first side X1 in the stacking direction at a speed of 50 mm/min with the surface LBb on the second side X2 in the stacking direction of the kitchen sponge LB in contact with a fixed plane, the compression load when the compression strain reaches 6.5% may be 30.0 N or less, 25.0 N or less, or 20.0 N or less.

In a compression test using a compression testing device, the kitchen sponge LB is preferably subjected to a compression load of 15.0 N or more, and more preferably 16.0 N or more, when the compression strain reaches 6.0% while the kitchen sponge LB is pressed from the first side X1 in the stacking direction at a speed of 50 mm/min with the surface LBb on the second side X2 in the stacking direction of the kitchen sponge LB in contact with a fixed plane. This increases the hardness of the portion of the kitchen sponge LB on the first side X1 in the stacking direction when the compression strain is 6.0%, thereby improving the dirt-scraping ability (especially for relatively fine dirt (specifically, dirt with a particle size of 100 μm or less (especially 10 to 70 μm)) when the user rubs the object to be cleaned with a soft touch (weak force) using the surface LBa (in this embodiment, the surface L1a on the first side X1 in the stacking direction of the surface layer L1) of the kitchen sponge LB.
Furthermore, in a compression test using a compression testing device, while the kitchen sponge LB is pressed from the first side X1 in the stacking direction at a speed of 50 mm/min with the surface LBb on the second side X2 in the stacking direction of the kitchen sponge LB in contact with a fixed plane, the compression load when the compression strain reaches 6.0% may be 30.0 N or less, 25.0 N or less, or 20.0 N or less.

In a compression test using a compression testing device, the kitchen sponge LB is preferably subjected to a compression load of 10.0 N or more, and more preferably 15.0 N or more, when the compressive strain reaches 5.6% while the kitchen sponge LB is pressed from the first side X1 in the stacking direction at a speed of 50 mm/min with the surface LBb on the second side X2 in the stacking direction of the kitchen sponge LB in contact with a fixed plane. This increases the hardness of the portion of the kitchen sponge LB on the first side X1 in the stacking direction when the compressive strain is 5.6%, thereby improving the dirt-scraping ability (especially for relatively fine dirt (specifically, dirt with a particle size of 100 μm or less (especially 10 to 70 μm)) when the user rubs the object to be cleaned with a soft touch (weak force) using the surface LBa (in this embodiment, the surface L1a on the first side X1 in the stacking direction of the surface layer L1) of the kitchen sponge LB.
Furthermore, in a compression test using a compression testing device, while the kitchen sponge LB is pressed from the first side X1 in the stacking direction at a speed of 50 mm/min with the surface LBb on the second side X2 in the stacking direction of the kitchen sponge LB in contact with a fixed plane, the compressive load at which the compressive strain reaches 5.6% may be 25.0 N or less, 20.0 N or less, or 17.0 N or less.

In a compression test using a compression testing device, the kitchen sponge LB is preferably subjected to a compression load of 10.0 N or more, and more preferably 13.0 N or more, when the compression strain reaches 5.0% while the kitchen sponge LB is pressed from the first side X1 in the stacking direction at a speed of 50 mm/min with the surface LBb on the second side X2 in the stacking direction of the kitchen sponge LB in contact with a fixed plane. This increases the hardness of the portion of the kitchen sponge LB on the first side X1 in the stacking direction when the compression strain is 5.0%, thereby improving the dirt-scraping ability (especially for relatively fine dirt (specifically, dirt with a particle size of 100 μm or less (especially 10 to 70 μm)) when the user rubs the object to be cleaned with a soft touch (weak force) using the surface LBa (in this embodiment, the surface L1a on the first side X1 in the stacking direction of the surface layer L1) of the kitchen sponge LB.
Furthermore, in a compression test using a compression testing device, while the kitchen sponge LB is pressed from the first side X1 in the stacking direction at a speed of 50 mm/min with the surface LBb on the second side X2 in the stacking direction of the kitchen sponge LB in contact with a fixed plane, the compressive load at which the compressive strain reaches 5.0% may be 25.0 N or less, 20.0 N or less, or 16.0 N or less.

In a compression test using a compression testing device, the kitchen sponge LB is preferably subjected to a compression load of 5.0 N or more, and more preferably 8.0 N or more, when the compressive strain reaches 4.0% while the kitchen sponge LB is pressed from the first side X1 in the stacking direction at a speed of 50 mm/min with the surface LBb on the second side X2 in the stacking direction of the kitchen sponge LB in contact with a fixed plane. This increases the hardness of the portion of the kitchen sponge LB on the first side X1 in the stacking direction when the compressive strain is 4.0%, thereby improving the dirt-scraping ability (especially for relatively fine dirt (specifically, dirt with a particle size of 100 μm or less (especially 10 to 70 μm)) when the user rubs the object to be cleaned with a soft touch (weak force) using the surface LBa (in this embodiment, the surface L1a on the first side X1 in the stacking direction of the surface layer L1) of the kitchen sponge LB.
Furthermore, in a compression test using a compression testing device, while the kitchen sponge LB is pressed from the first side X1 in the stacking direction at a speed of 50 mm/min with the surface LBb on the second side X2 in the stacking direction of the kitchen sponge LB in contact with a fixed plane, the compression load at which the compression strain reaches 4.0% may be 20.0 N or less, 15.0 N or less, or 10.0 N or less.

In a compression test using a compression testing device, when the kitchen sponge LB is pressed from the first side X1 in the stacking direction at a speed of 50 mm/min with the surface LBb on the second side X2 in the stacking direction of the kitchen sponge LB in contact with a fixed plane, it is preferable that the compressive strain when the compressive load reaches 8.6 N is 5.0% or less, more preferably 4.5% or less, and even more preferably 4.2% or less. This allows the hardness of the portion of the kitchen sponge LB on the first side X1 in the stacking direction to be increased from a lower compressive strain, thereby improving the dirt-scraping ability (especially against relatively fine dirt (specifically, dirt with a particle size of 100 μm or less (especially 10 to 70 μm)) when the user rubs the object to be cleaned with a soft touch (weak force) using the surface LBa (in this embodiment, the surface L1a on the first side X1 in the stacking direction of the surface layer L1) of the kitchen sponge LB.
Furthermore, in a compression test using a compression testing device, while the kitchen sponge LB is pressed from the first side X1 in the stacking direction at a speed of 50 mm/min with the surface LBb on the second side X2 in the stacking direction of the kitchen sponge LB in contact with a fixed plane, the compressive strain when the compressive load reaches 8.6 N may be 3.2% or more, or 3.8% or more.

In a compression test using a compression testing device, the kitchen sponge LB is preferably subjected to a compression load of 35.0 N or more, and more preferably 38.0 N or more, when the compressive strain reaches 40.0% while the kitchen sponge LB is pressed from the first side X1 in the stacking direction at a speed of 50 mm/min with the second side X2 in the stacking direction of the kitchen sponge LB in contact with a fixed plane. This increases the hardness of the portion of the kitchen sponge LB on the first side X1 in the stacking direction when the compressive strain is 40.0%, thereby improving the dirt-scraping ability (especially for relatively fine dirt (specifically, dirt with a particle size of 100 μm or less (especially 10 to 70 μm)) when the user rubs the object to be cleaned with normal (i.e., a moderate, commonly used) force using the surface LBa (in this embodiment, the surface L1a of the surface layer L1 on the first side X1 in the stacking direction) of the kitchen sponge LB.
From a similar viewpoint, in a compression test using a compression testing device, the kitchen sponge LB is preferably 35.0 N or more, and more preferably 38.0 N or more, when the compressive load at which the compressive strain reaches 40.6% is applied while the kitchen sponge LB is pressed from the first side X1 in the stacking direction at a speed of 50 mm/min with the second side X2 in the stacking direction of the kitchen sponge LB in contact with a fixed plane.
Furthermore, in a compression test using a compression testing device, when the kitchen sponge LB is pressed from the first side X1 in the stacking direction at a speed of 50 mm/min with the second side X2 of the kitchen sponge LB in contact with a fixed plane, it is preferable that the difference between the minimum and maximum values of the compressive load within the range of 40.0 to 50.0% is 6.0 N or less, and more preferably 5.2 N or less. This allows the hardness of the portion of the kitchen sponge LB on the first side X1 in the lamination direction to remain almost constant when the compressive strain is 40-50%. As a result, even if the force applied by the user to rub the object to be cleaned with normal (i.e., moderate) force using the surface LBa (in this embodiment, the surface L1a on the first side X1 in the lamination direction of the surface layer L1) of the kitchen sponge LB, the dirt-removing ability (especially the dirt-removing ability against relatively fine dirt (specifically, dirt with a particle size of 100 μm or less (especially 10-70 μm))) can be maintained almost constant, even if the force applied fluctuates somewhat, and consequently, the stability of the user's perceived feel can be improved.
From a similar viewpoint, in a compression test using a compression testing device, when the kitchen sponge LB is pressed from the first side X1 in the stacking direction at a speed of 50 mm/min with the second side X2 of the kitchen sponge LB in contact with a fixed plane, it is preferable that the difference between the minimum and maximum values of the compressive load within the range of 40.6 to 50.3% of the compressive strain is 5.0 N or less, and more preferably 4.0 N or less.
Furthermore, in a compression test using a compression testing device, while the kitchen sponge LB is pressed from the first side X1 in the stacking direction at a speed of 50 mm/min with the second side X2 of the kitchen sponge LB in contact with a fixed plane, the compression load at which the compression strain reaches 40.0% may be 50 N or less, 45 N or less, or 41 N or less.
Similarly, in a compression test using a compression testing device, while the kitchen sponge LB is pressed from the first side X1 in the stacking direction at a speed of 50 mm/min with the second side X2 of the kitchen sponge LB in contact with a fixed plane, the compressive load at which the compressive strain reaches 40.6% may be 50 N or less, 45 N or less, or 41 N or less.

The following will provide a more detailed explanation of the preferred configuration of the kitchen sponge LB. The preferred values of the various measurements obtained through the compression test described above can be achieved by appropriately adjusting the hardness, thickness, and material of each layer constituting the kitchen sponge LB. For example, this can be more easily achieved through the various configurations described below.

The urethane foam forming the base layer L3, the intermediate layer L2, and the surface layer L1 may be either ester-based or ether-based urethane foam.

Ester-based polyurethane foam is formed by reacting polyester polyols, obtained by reacting aliphatic dicarboxylic acids (such as succinic acid, oxalic acid, malonic acid, and adipic acid) with aliphatic and/or alicyclic polyols (such as ethylene glycol, propylene glycol, and 1,4-butanediol), with polyisocyanates (such as TDI, MDI, TODI, and XDI). The resulting foam is cellular, and typically the cell membrane adheres to all the structural elements. Its properties include minimal variation in cell characteristics, excellent appearance, high tensile strength and elongation, and superior oil and solvent resistance.

The base layer L3 and the surface layer L1 are preferably three-dimensional networked urethane foam having interconnected cells. Three-dimensional networked urethane foam is urethane foam from which the cell membrane has been removed, leaving only the framework and exhibiting a three-dimensional network structure. Typically, this cell membrane removal is performed by a known explosive method. Since the removed cell membrane adheres integrally to the framework, the resulting foam exhibits superior strength, oil resistance, and solvent resistance compared to the untreated foam.

The intermediate layer L2 is preferably a urethane foam with the cell membranes intact. However, some of the cell membranes may have pores that communicate with each other. In this case, since the urethane foam of the intermediate layer L2 has not had the cell membranes removed, the intermediate layer L2 has a function of retaining detergent and water (retention function).

As described above, the base layer L3 is preferably an uncompressed molded product. The base layer L3 is preferably a urethane foam with the cell membrane intact. In this case, the base layer L3 has a function (foaming function) that allows the detergent to quickly penetrate and create a lather rapidly, thereby increasing the cleaning power.

The Asker F hardness of the surface layer L1 is preferably 55 or higher, and more preferably 60 or higher. This improves the dirt-scraping ability when the user rubs the surface layer L1 against the object to be cleaned.
Furthermore, the Asker F hardness of the surface layer L1 is preferably 88 or less, and more preferably 83 or less. This improves the resistance to scratching when the user rubs the surface layer L1 against the object to be cleaned.
In this specification, the "Asker F hardness" of any component (surface layer L1, intermediate layer L2, base layer L3, etc.) refers to the measurement value obtained from the Asker rubber hardness tester Type F (manufactured by Polymer Instruments Co., Ltd.) after the component has been placed on a horizontal platform and the measurement value of the tester has stabilized (for example, between 20 seconds and 1 minute 30 seconds after placement). The time until measurement may be adjusted as appropriate to allow the tester to stabilize after being placed on the component.

The Asker F hardness of the surface layer L1 is preferably greater than that of the intermediate layer L2. This improves the ability to scrape off dirt.
Furthermore, it is preferable that the Asker F hardness of the surface layer L1 is greater than that of the base layer L3.

The thickness of the surface layer L1 (length in the lamination direction X) is preferably 6 mm or less, more preferably 4 mm or less, and even more preferably 3 mm or less. This allows for an even better balance between dirt removal and scratch resistance. It also improves the ability to conform to the shape of the object being cleaned.
Furthermore, the thickness of the surface layer L1 is preferably 1 mm or more.

The thickness of the intermediate layer L2 (length in the lamination direction X) is preferably 2 to 4 times the thickness of the surface layer L1.
The thickness of the base layer L3 (length in the lamination direction X) is preferably 3.5 to 7 times the thickness of the surface layer L1.
These features allow for an even better balance between dirt-removing properties and scratch resistance.

The thickness of the intermediate layer L2 may be, for example, 9 to 11 mm.
The thickness of the base layer L3 may be, for example, 17 to 19 mm.

The density of the urethane foam constituting the surface layer L1 before compression molding may be, for example, 27.5 to 32.5 kg/ ^m³ .
The density of the intermediate layer L2 may be, for example, 29 to 33 kg/ ^m³ .
The density of the base layer L3 may be, for example, 26 to 30 kg/ ^m³ .
Here, "density" shall be measured in accordance with JIS K6400-1.

The hardness (N) of the surface layer L1 before compression molding may be, for example, 105 to 155 N.
The hardness (N) of the intermediate layer L2 may be, for example, 150 to 250 N.
The hardness (N) of the base layer L3 may be, for example, 70 to 130 N.
Here, "hardness (N)" refers to the 25% ILD hardness measured in accordance with JIS K6400-2 (Method D).

The number of cells in the compression-molded urethane foam used as the surface layer L1 may be 5 to 10 cells per inch.
The number of cells in the intermediate layer L2 of the urethane foam may be 25 to 35 cells per inch.
The number of cells in the base layer L3 urethane foam may be 10 to 20 cells per inch.

The compression ratio of the compressed molded product as the surface layer L1 is preferably 4.5 or higher, and more preferably 5 or higher. This improves the ability to scrape off dirt.
Furthermore, the compression ratio of the compression-processed molded product as the surface layer L1 is preferably less than 7. This improves its resistance to scratches.

It is preferable that the surface layer L1 is positioned such that the compression direction during the compression molding process of the compressed molded product coincides with the lamination direction X of the kitchen sponge LB. This facilitates the integrated manufacturing of the base layer L3, intermediate layer L2, and surface layer L1 as a laminate. Furthermore, it facilitates the transfer of foaming from the base layer L3 and intermediate layer L2 to the surface layer L1.

The above describes exemplary embodiments of the present invention, and various modifications can be made without departing from the scope of the claims.
For example, the kitchen sponge LB may further comprise other layers in addition to the surface layer L1, intermediate layer L2, and base layer L3. Specifically, for example, another layer may be formed on the surface L3b of the base layer L3 on the second side X2 in the lamination direction. The material of the other layer is not limited to urethane foam and can be any material. Specifically, the other layer can be formed using, for example, organic fibers such as cellulose, or foamed resins such as melamine foam, polyethylene foam, and polypropylene foam.

Kitchen sponges LB according to Example 1 and Comparative Examples 1 to 4 were prepared and evaluated, and the results are described below. When values such as compressibility, compressive load, and strain are stated to one decimal place, the values were rounded to two decimal places.
The specifications of the kitchen sponge LB for each example are shown in Table 1.
For each example of kitchen sponge LB, in a compression test using the above-described compression testing apparatus, the kitchen sponge LB was pressed from the first side X1 in the stacking direction at a speed of 50 mm/min with the surface LBb on the second side X2 in the stacking direction of the kitchen sponge LB in contact with a fixed plane until the compressive strain reached a maximum of 75.1%. The compressive load-compressive strain curve is shown in Figure 4, and the maximum value of the compressive load measured during the pressing is shown in Figure 2.
For each example of kitchen sponge LB, in a compression test using the above-described compression testing apparatus, the maximum value of the compressive load measured while pressing the kitchen sponge LB from the second side X2 in the stacking direction at a speed of 50 mm/min with the surface LBa on the first side X1 in the stacking direction of the kitchen sponge LB in contact with a fixed plane until the compressive strain reached a maximum of 75.1% is shown in Figure 3. Note that Figures 2 and 3 are shown as integers, rounded to the nearest whole number.

In the compression test shown in Figure 4, the kitchen sponge LB of Example 1 had a compressive load of 8.6 N when the compressive strain reached 4.0%, a compressive load of 16.2 N when the compressive strain reached 5.6%, and a compressive load of 17.9 N when the compressive strain reached 6.5%.
Furthermore, in the compression test shown in Figure 4, the kitchen sponge LB of Example 1 exhibited a compressive strain of 4.0% when the compressive load reached 8.6 N.
Furthermore, in the compression test shown in Figure 4, the kitchen sponge LB of Example 1 had a compressive load of 39.2 N when the compressive strain reached 40.6%.
Furthermore, in the compression test shown in Figure 4, the difference between the minimum and maximum compressive loads within the range of 40.6% to 50.3% for the kitchen sponge LB of Example 1 was 3.7 N.

For each example of the LB kitchen sponge, we evaluated its ability to remove dirt, its resistance to scratching, and its overall usability.
In evaluating the dirt-removing ability, a sample of kitchen sponge LB was obtained by cutting it to a width of 50 mm, and the thickness of the sample was measured. The sample was then gradually compressed in the thickness direction, and the thickness of the sample when the compressive load reached 20 N (hereinafter referred to as the "set thickness") was determined. After that, the sample was set in the measuring device so that its thickness became the set thickness. The measuring device consisted of upper and lower plates facing each other in the vertical direction, multiple spacers placed between the upper and lower plates, and sandpaper. The sample was placed between the upper and lower plates with the surface layer L1 of the sample facing upward, and the distance between the upper and lower plates was adjusted using the spacers to adjust the thickness of the sample to the set thickness. The sandpaper had a grit of 1000 and a width of 10 mm. By using a grit of 1000 sandpaper, it was possible to evaluate the dirt-removing ability against relatively fine dirt (specifically, dirt with a particle size of 100 μm or less (especially 10 to 70 μm)). The sandpaper was placed between the sample and the top plate, with the length of the sandpaper aligned with the width of the sample. The jig with the sandpaper attached was then pulled 20 mm in the width direction of the sample, and the frictional force between the sample's surface L1 and the sandpaper was measured. The tensile force acting on the tip of the plate with the sandpaper attached was measured using a tensile testing machine, and this measurement was defined as the frictional force. The frictional force was also measured similarly for compressive loads of 40 N and 60 N. For each of the compressive loads of 20 N, 40 N, and 60 N, the measured frictional force was used as an index value to evaluate the dirt-scraping ability. A new sample and sandpaper were used for each measurement. The results are shown in Table 1. A higher index value indicates higher frictional force, and therefore, higher dirt-scraping ability against relatively fine dirt (specifically, dirt with a particle size of 100 μm or less (especially 10-70 μm)). When the compressive load was set to 20N, it simulated rubbing the object to be cleaned with a weak force; when the compressive load was set to 40N, it simulated rubbing the object to be cleaned with a normal force; and when the compressive load was set to 60N, it simulated rubbing the object to be cleaned with a slightly stronger force.
In evaluating scratch resistance, the surface LBa of the kitchen sponge LB on the first side X1 in the lamination direction (i.e., the surface L1a of the surface layer L1 on the first side X1 in the lamination direction) was used to evaluate the scratch resistance when rubbing the object being cleaned with strong force, using a four-level scale: ◎ (Excellent), ○ (Good), △ (Fair), and × (Poor). The results are shown in Table 1.
In evaluating the feel of the sponge, the ease with which the kitchen sponge LB conformed to the hand when held from the second side X2 in the stacking direction was evaluated on a two-point scale: ○ and △. ○ indicates that it is moderately soft and conforms well to the hand. △ indicates that it does not conform well to the hand. The results are shown in Table 1.

As can be seen from the results in Table 1, the kitchen sponge LB of Example 1 achieves a better balance of dirt-removing ability and scratch resistance compared to the kitchen sponges LB of Comparative Examples 1 to 4. Comparative Example 1, as can be seen from Figures 2 and 4, has a hard surface and excellent dirt-removing ability, but the surface is too hard and is made of a nonwoven fabric containing abrasives, making it prone to scratching. Comparative Example 2 is similar to Example 1 in that the surface is made of a compressed urethane foam molded product and is not prone to scratching, but as can be seen from Figures 2 and 4, the surface is not hard enough, resulting in weak dirt-removing ability and inferior cleaning power compared to Example 1. Comparative Example 3 has values close to Example 1 as shown in Figures 2 and 3, but the surface is made of a nonwoven fabric containing abrasives, making it more prone to scratching compared to Example 1. Comparative Example 4, as can be seen from Figures 2 and 4, has a soft surface, but the surface is made of a nonwoven fabric containing abrasives, making it prone to scratching. Regarding usability, while Examples 1, 2, and 3 yielded good results, Comparative Example 1 was too hard and difficult to hold, and Comparative Example 4 was too soft and difficult to hold and wash.

The kitchen sponge according to the present invention is suitable for use in cleaning kitchen items such as dishes and cooking utensils.

LB: Kitchen sponge, LBa: First side in the lamination direction, LBb: Second side in the lamination direction,
L1: Surface layer, L1a: Surface on the first side in the stacking direction, L1b: Surface on the second side in the stacking direction
L2: Intermediate layer, L2a: Surface on the first side in the stacking direction, L2b: Surface on the second side in the stacking direction,
L3: base layer, L3a: surface on the first side in the stacking direction, L3b: surface on the second side in the stacking direction,
X: stacking direction, X1: first side in the stacking direction, X2: second side in the stacking direction

Claims (7)

The base layer,
An intermediate layer formed on the first side of the stacking direction of the base layer,
A surface layer formed on the first side of the intermediate layer in the stacking direction,
A kitchen sponge equipped with,
The base layer, the intermediate layer, and the surface layer are each made of urethane foam.
The aforementioned surface layer is a compressed and molded product of urethane foam.
A kitchen sponge in which, while the kitchen sponge is pressed from the first side in the stacking direction at a speed of 50 mm/min with the second side of the kitchen sponge in contact with a fixed plane, the compressive load when the compressive strain reaches 5.6% is 10.0 N or more. The kitchen sponge according to claim 1, wherein, while the kitchen sponge is pressed from the first side in the stacking direction at a speed of 50 mm/min with the second side of the kitchen sponge in contact with a fixed plane, the compressive strain when the compressive load reaches 8.6 N is 5.0% or less. The kitchen sponge according to claim 1 or 2, wherein, while the kitchen sponge is pressed from the first side in the stacking direction at a speed of 50 mm/min with the second side in the stacking direction in contact with a fixed plane, the compressive load when the compressive strain reaches 40.6% is 35.0 N or more, and the difference between the minimum and maximum compressive loads within the range of 40.6% to 50.3% compressive strain is 5.0 N or less. The kitchen sponge according to claim 1 or 2, wherein the maximum value of the compressive load measured while the kitchen sponge is pressed from the first side in the stacking direction at a speed of 50 mm/min until the compressive strain reaches a maximum of 75.1%, with the second side of the kitchen sponge in the stacking direction in contact with a fixed plane, is 200 N or more. The kitchen sponge according to claim 1 or 2, wherein the Asker F hardness of the surface layer is 55 to 88. The kitchen sponge according to claim 1 or 2, wherein the thickness of the surface layer is 6 mm or less. The thickness of the intermediate layer is 2 to 4 times the thickness of the surface layer.
The kitchen sponge according to claim 1 or 2, wherein the thickness of the base layer is 3.5 to 7 times the thickness of the surface layer.