JP7764646B2 - How to improve fragrance longevity, bath salts - Google Patents

Description

The present invention relates to a method for improving the persistence of fragrance, a foamable compression molded product, and a bath additive.

In recent years, it has become common to add bath additives to bathwater to give it a refreshing fragrance or color, to stimulate metabolism and improve sensitivity to cold, and to obtain a warming effect. Various types of bath additives are sold, including bath salts, tablets, and liquids. Among these, bath additives containing a carbon dioxide gas generator, a combination of carbonate and acid, generate carbon dioxide gas in the bathwater. The carbon dioxide dissolved in the bathwater dilates capillaries and boosts metabolism, and is expected to have effects such as promoting blood circulation and relieving fatigue.

Furthermore, one of the important effects expected from bath additives is the aromatherapy effect of the scent, and maintaining a stable scent is important to enhance this effect while bathing. Therefore, Patent Document 1 reports a technology for enhancing the fragrance of bath additives by making them into granular bath additives with small particle diameters and large surface areas.

JP 2009-062319 A

Until now, foaming bath additives combining carbonates and acids have been popular, compressed into solid tablets or other forms that sink into the bathwater, making it easier for the generated carbon dioxide gas to dissolve in the bathwater. However, because these bath additives sink in the bathwater, they do not release as much fragrance as granular bath additives. On the other hand, adding a large amount of fragrance to compressed solid bath additives in order to improve the release of the fragrance can potentially reduce the stability of the formulation.

Another issue with compressed solid bath additives is that while the scent is easily detectable immediately after dissolving, the scent does not last. In particular, users who dissolve the additive in bathwater can easily detect the scent, but those who take a subsequent bath find it difficult to detect.

The present invention aims to provide an expandable compression-molded product that has good fragrance release and enhanced fragrance persistence, and to provide a method for improving the fragrance persistence of an expandable compression-molded product. In this invention, "fragrance release" means that the fragrance diffuses and can be felt immediately after the expandable compression-molded product is dissolved in water or the like.

The present invention is as follows.
(1) A bath additive comprising a foamable compression molded product having a recess and containing a fragrance,
a volume ratio of the volume of the recessed portion to the volume of the expandable compression-molded product [volume of the recessed portion/volume of the expandable compression-molded product] of 0.03 or more;
When the bath additive is submerged in water, the generated gas is temporarily retained in the recess, and bubbles with a diameter of 1 cm or more can be released into the water.

(2) The bath additive according to (1), wherein the volume of the recess is 2000 ^mm3 or more.
(3) The bath additive according to (1) or (2), wherein the volume ratio [volume of the recessed portion/volume of the foamable compression-molded product] is 0.15 or less.
(4) containing an organic acid;
The bath additive according to any one of (1) to (3), wherein the organic acid content is 10 to 65% by mass.
(5) containing carbonate;
The bath additive according to any one of (1) to (4), wherein the carbonate content is 20 to 90% by mass.

(6) A method for improving the persistence of a fragrance by using a bath additive made of a foamable compression-molded product containing a fragrance, comprising:
The expandable compression-molded product has a recess,
a volume ratio of the volume of the recessed portion to the volume of the expandable compression-molded product [volume of the recessed portion/volume of the expandable compression-molded product] of 0.03 or more;
The method for improving the persistence of fragrance of the bath additive is such that when the bath additive is submerged in water, the gas generated is temporarily retained within the recess and bubbles having a diameter of 1 cm or more are released into the water.

The present invention provides a foamable compression-molded product that has a good fragrance and long-lasting fragrance, and also improves the long-lasting fragrance of the foamable compression-molded product.

FIG. 1 is a perspective view of an expandable compression-molded product according to an embodiment of the present invention. FIG. 2 is a top view of an expandable compression-molded product according to an embodiment of the present invention. FIG. 3 is a cross-sectional view of an expandable compression-molded product according to an embodiment of the present invention. FIG. 4 is a cross-sectional view of an expandable compression-molded product according to an embodiment of the present invention. FIG. 5 is a graph showing the change over time in fragrance intensity of the expandable compression-molded products of Examples 1 to 4 and Comparative Example 1. FIG. 6 is a graph showing the change over time in fragrance intensity of the expandable compression-molded products of Examples 5 to 7. FIG. 7 is a graph showing the change over time in fragrance intensity of the expandable compression-molded products of Examples 8 to 10 and Comparative Example 2. FIG. 8 is a graph showing the change over time in fragrance intensity of the expandable compression-molded products of Examples 11 to 13. FIG. 9 is a graph showing the change over time in fragrance intensity of the expandable compression-molded products of Examples 14 to 18.

[Method for improving fragrance durability]
The method for improving the fragrance persistence of this embodiment is a method for improving the fragrance persistence of a fragrance using an expandable compression-molded product containing a fragrance. Here, the expandable compression-molded product has a top surface, a bottom surface, and a side surface, and at least one of the top surface and the bottom surface has a recess. In the method for improving the fragrance persistence of this embodiment, the expandable compression-molded product is placed so that the top surface having the recess or the bottom surface having the recess contacts the bottom of a water tank, and is reacted with water.
This method can improve the persistence of the fragrance of the fragrance. The reason for this is thought to be that the gas generated in the water temporarily remains in the depressions, and the retained gas combines with itself to form large bubbles that are released into the water, and the large bubbles burst near the water surface, increasing the intensity of the fragrance, and the continuous generation of large bubbles makes it easier to continuously release a strong fragrance.
The expandable compression molded product will be described in detail later.

In the method for improving the fragrance persistence of this embodiment, it is preferable to use hot water (35-45°C) rather than cold water to optimize the release of the fragrance. Furthermore, it is preferable to use 100-200 L of hot water per expandable compression-molded product.

[Expandable compression molded product]
Fig. 1 shows a perspective view of an expandable compression-molded product 100 of this embodiment. Fig. 2 shows a top view of the expandable compression-molded product 100 of this embodiment. Fig. 3 is a cross-sectional view of the expandable compression-molded product 100 of this embodiment, taken along the line A-A of the expandable compression-molded product 100 of Fig. 2. Fig. 4 is a cross-sectional view of an expandable compression-molded product 200 according to another embodiment of the present invention.
The expandable compression molded products 100 and 200 have a top surface 1, a bottom surface 2, and a side surface 3. The expandable compression molded product 100 in Fig. 1 is cylindrical, but is not particularly limited thereto. In order for the expandable compression molded product to have a top surface, a bottom surface, and a side surface, it is preferably cylindrical, and more preferably cylindrical or polygonal. When the expandable compression molded product has a cylindrical shape, the top surface is one surface intersecting the axial direction of the expandable compression molded product, and the bottom surface is the other surface intersecting the axial direction of the expandable compression molded product.

The expandable compression molded product of this embodiment has a recess on at least one of its top and bottom surfaces. As shown in Figures 1 to 3, it may have a recess 11 on top surface 1, or it may have a recess on the bottom surface (not shown). Furthermore, as shown in Figure 4, it may have recesses 11, 21 on both top surface 1 and bottom surface 2, respectively. From the perspective that the effects of the present invention can be achieved whether the top or bottom surface is placed so that it is in contact with the bottom of the water tank, it is preferable to have recesses on both the top and bottom surfaces, because when the expandable compression molded product is placed in a bathtub or the like, the recesses will come into contact with the bottom of the water layer without the need to consider the positional relationship between the recess and the bottom of the water layer.

As shown in Figures 1 to 4, the shape of the top surface 1 having the recess 11 other than the recess may include an edge 12 and a chamfered portion 13 that connects to the side surface 3. Having the edge 12 is preferable because it makes it easier for bubbles to remain in the space within the recess. The edge 12 preferably surrounds the periphery of the recess, and may have a notch (groove) in part to adjust the size of the bubbles and allow them to be discharged. It is more preferable to have an edge that surrounds the entire periphery of the recess. Furthermore, having the chamfered portion 13 is preferable because it can prevent cracking or chipping of the expandable compression molded product.

As shown in Figure 4, even when the bottom surface 2 has a recess 21, the bottom surface 2 may also have an edge portion 22 and a chamfered portion 23 connecting to the side surface 3 in addition to the recess.

Although not shown, the shape of the recess is not limited. It may be a hemispherical shape as shown in Figures 1 to 4, or a spherical shape, a polyhedral shape, a columnar shape, or a combination thereof. The shape of the cross section of the recess in a direction intersecting the axial direction may be a circle, an ellipse, a star, a cross, a polygon, the shape of various characters, or a combination thereof. Furthermore, the recess may have various other uneven shapes.
The number of recesses is not limited as long as it is one or more, and may be two or more.

In the expandable compression molded product of this embodiment, the volume of the recesses is preferably 2000 mm ^or more, more preferably 2500 mm ^or more. When the volume of the recesses is 2000 mm ^or more, bubbles tend to remain in the space within the recesses, making it easier for large bubbles to be generated. The upper limit of the volume of the recesses is preferably 6000 mm ^or less, more preferably 5500 mm ^or less, and even more preferably 5000 mm ^or less. When the volume of the recesses is 6000 mm ^or less, cracking and chipping of tablets during line conveyance or transport can be suppressed. When the volume of the recesses is within the above range, the period during which large bubbles are generated can be extended, thereby improving the release and persistence of the fragrance of the fragrance.
The volume of the recess can be calculated, for example, by filling the recess of the expandable compression molded product loosely to the level without tapping with sodium sulfate (powder) of known bulk density, and then calculating it from the mass of the filled sodium sulfate and the bulk density.

The desired shape and volume of the recesses can be achieved, for example, by using a compression molding mold with protrusions of the desired shape and volume when compression molding the expandable compression-molded product, and then transferring the shape of the protrusions to form the recesses; or by compression molding the top or bottom surface of a flat plate, and then scraping the top or bottom surface to achieve the desired shape and volume.

In the expandable compression molded product of this embodiment, the volume ratio of the volume of the recessed portion to the volume of the expandable compression molded product [volume of recessed portion/volume of expandable compression molded product] is preferably 0.03 or more, more preferably 0.04 or more. It is believed that when the bubbles retained in the recessed portions of the expandable compression molded product grow to a certain size and their buoyancy increases, the expandable compression molded product floats up, and large bubbles are released into the water through the resulting gaps. A volume ratio of the volume of the recessed portion to the volume of the expandable compression molded product of 0.03 or more is preferred because it facilitates the occurrence of the above phenomenon and improves the release and persistence of the fragrance. The upper limit of the volume ratio of the volume of the recessed portion to the volume of the expandable compression molded product is preferably 0.15 or less, more preferably 0.1 or less. A volume ratio of the volume of the recessed portion to the volume of the expandable compression molded product of 0.15 or less can prevent cracking or chipping of the expandable compression molded product during line conveyance or transport. Furthermore, when the expandable compression-molded product is dissolved, the time it takes for the top and bottom surfaces of the expandable compression-molded product to be pierced can be increased, thereby lengthening the time during which large bubbles are continuously generated.

The expandable compression-molded product of this embodiment preferably has a maximum diameter of 65 mm or more, more preferably 68 mm or more. A maximum diameter of 65 mm or more is preferable because it can further increase the persistence of the scent. The upper limit of the maximum diameter is preferably 80 mm or less, more preferably 75 mm or less. A maximum diameter of 80 mm or less can prevent the expandable compression-molded product from cracking or chipping during line conveyance or transportation.
The maximum diameter refers to the diameter of a circumscribing circle when the expandable compression-molded product is viewed from the axial direction.

From the viewpoint of fragrance sustainability, the expandable compression molded product of this embodiment preferably has a thickness of 13 mm or more, more preferably 16 mm or more, and preferably 20 mm or less, more preferably 18 mm or less.

The expandable compression molded product of this embodiment has a density of preferably 1.3 g/cm ^or more, more preferably 1.6 g/cm ^or more, and preferably 2.5 g/cm ^or less, more preferably 2.0 g/cm ^or less. By keeping the density within the above range, an appropriate amount of foaming can be achieved, resulting in good fragrance release and long-lasting fragrance of the fragrance. Furthermore, cracking and chipping of the expandable compression molded product during line conveyance or transportation can be suppressed.

The expandable compression molded product of this embodiment has a volume of preferably 40,000 mm ^{or more} , more preferably 50,000 mm or ^more , from the viewpoint of fragrance sustainability, and preferably 75,000 mm ^or less, more preferably 65,000 mm ^or less, in order to prevent cracking or chipping of the expandable compression molded product during line conveyance or transportation. By having the volume within the above range, the fragrance of the fragrance will be good and the fragrance will be long-lasting.

The expandable compression-molded product of this embodiment preferably has a mass of 52 g or more, more preferably 80 g or more, even more preferably 90 g or more, and preferably 150 g or less, more preferably 120 g or less, even more preferably 100 g or less. Within the above ranges, increasing the amount of carbon dioxide gas foaming can improve the release and persistence of the fragrance.

The foamable compression molded product of this embodiment preferably has a foaming volume of 700 mL or more, more preferably 800 mL or more, and even more preferably 1300 mL or more. A foaming volume of 700 mL or more can increase the persistence of the fragrance. The upper limit is preferably 2000 mL or less, more preferably 1400 mL or less. A foaming volume of 2000 mL or less can increase the amount of carbon dioxide gas dissolved in the bath water. In addition, choking caused by powder in the foamable compression molded product flying up due to foaming can be suppressed.
The foaming amount can be determined, for example, by placing one tablet of the foamable compression-molded product in a metal mesh basket (diameter 10 cm x height 10 cm), immersing this in 200 L of bath water at 40°C, placing an upside-down funnel just above the top surface of the metal mesh basket in the water, and collecting all of the generated carbon dioxide gas in a measuring cylinder, and measuring the amount of carbon dioxide gas generated.
In order to achieve a desired foaming amount, for example, the types and contents of the organic acid and carbonate may be adjusted.

The disintegration time of the expandable compression-molded product of this embodiment is preferably 180 seconds or more, 190 seconds or more, 210 seconds or more, 240 seconds or more, 270 seconds or more, 300 seconds or more, 330 seconds or more, or 360 seconds or more, and is preferably 960 seconds or less, 930 seconds or less, 900 seconds or less, 840 seconds or less, 780 seconds or less, 720 seconds or less, 660 seconds or less, 600 seconds or less, 540 seconds or less, 480 seconds or less, or 420 seconds or less. By setting the disintegration time within the above range, it is possible to increase the persistence of the fragrance while ensuring a satisfactory level of fragrance immediately after dissolution of the expandable compression-molded product. Furthermore, it is possible to efficiently increase the carbon dioxide concentration in the bathwater.
The disintegration time is the time required for the expandable compression molded product to completely dissolve.
In order to achieve a desired disintegration time, for example, the compounding ratio of the organic acid and carbonate in the expandable compression-molded product, the mass, volume, density or tableting pressure may be adjusted.

The expandable compression molded product of this embodiment can release bubbles with a diameter of 1 cm or more into water. By generating large bubbles with a diameter of 1 cm or more, the user can feel a strong scent when the large bubbles burst near the water surface.
The number of bubbles having a diameter of 1 cm or more generated per tablet of the expandable compression-molded product is preferably 50 or more, more preferably 80 or more.
In order to release a predetermined number of bubbles with a diameter of 1 cm or more into water, as described above, the foamable compression molded product is placed so that the top surface having a recess or the bottom surface having a recess is in contact with the bottom surface of the water tank, preferably the volume of the recess is a certain amount or more, and preferably the ratio of the volume of the recess to the volume of the foamable compression molded product is a certain amount or more.

The expandable compression-molded product of this embodiment preferably generates bubbles having a diameter of 1 cm or more for a period of 60 seconds or more, more preferably 120 seconds or more. The continuous generation of large bubbles allows the continuous release of a strong fragrance, improving the persistence of the fragrance.
The period for generating bubbles having a diameter of 1 cm or more can be set within the above range by adjusting, for example, the volume of the recesses, the ratio of the volume of the recesses to the volume of the expandable compression-molded product, the amount of foaming, the collapse time, etc.

Next, we will explain each of the ingredients in the expandable compression-molded product of this embodiment.

(fragrance)
Flavorings include natural flavorings extracted from various plants and animals, synthetic flavorings that are chemically synthesized, and compound flavorings made by mixing a number of these flavoring ingredients.
Fragrances can be found in various literature, for example, "Perfume and Flavor Materials of Natural Origin", Steffen Arctander, Allured Pub. Co. (1960), "Encyclopedia of Fragrances", edited by the Japan Fragrance Association, Asakura Shoten (1989), "Flower oils and Floral Compounds in Perfumery", Danute Pajaujis Anonis, Allured Pub. Co. (1993), "Perfume and Flavor Chemicals (aroma chemicals)", Vols. I and II, Steffen Arctander, Allured Pub. Co. (1994), "Fundamentals of Fragrance and Fragrance Blending," edited by Nakajima Mototaka, Sangyo Tosho (1995), "Synthetic Fragrances: Chemistry and Product Knowledge," written by Indo Genichi, Kagaku Kogyo Nipposha (1996), and "Encyclopedia of Fragrances," edited by Yatagai Mitsukatsu, Maruzen (2005) can be used. Each of these is incorporated by reference into the disclosure of this specification. Representative examples of fragrances are specifically listed below, but are not limited to these.

Examples of natural fragrances include natural essential oils such as orange oil, lemon oil, lavender oil, lavandin oil, bergamot oil, patchouli oil, cedarwood oil, and peppermint oil.
Examples of synthetic fragrances include hydrocarbon terpenes such as α-pinene, β-pinene, limonene, p-cymene, terpinolene, α-terpinene, γ-terpinene, α-phellandrene, myrcene, camphene, and ocimene; heptanal, octanal, decanal, benzaldehyde, salicylic aldehyde, phenylacetaldehyde, citronellal, hydroxycitronellal, and hydrotropic aldehyde. Aldehydes such as cinnamic aldehyde, ligustral, citral, α-hexyl cinnamic aldehyde, α-amyl cinnamic aldehyde, lilial, cyclamen aldehyde, lyral, heliotropin, anisaldehyde, helional, vanillin, and ethyl vanillin; ethyl formate, methyl acetate, ethyl acetate, methyl propionate, methyl isobutyrate, and ethyl isobutyrate; Ethyl butyrate, propyl butyrate, isobutyl acetate, isobutyl isobutyrate, isobutyl butyrate, isobutyl isovalerate, ethyl 2-methylvalerate, isoamyl acetate, terpinyl acetate, isoamyl propionate, amyl propionate, amyl isobutyrate, amyl butyrate, amyl isovalerate, allyl hexanoate, ethyl acetoacetate, ethyl heptylate, heptyl acetate, methyl benzoate, ethyl benzoate, ethyl octylate, styrallyl acetate, benzyl acetate, nonyl acetate, bornyl acetate, linalyl acetate, ortho-tert-butylcyclohexyl acetate, linalyl benzoate, benzyl benzoate, triethyl citrate, ethyl cinnamate, methyl salicylate, hexyl salicylate Esters and lactones such as methyl jasmonate, methyl dihydrojasmonate, ethylene brassylate, γ-undecalactone, γ-nonyl lactone, cyclopentadecanolide, and coumarin; ethers such as anisole, p-cresyl methyl ether, dimethylhydroquinone, methyl eugenol, β-naphthol methyl ether, β-naphthol ethyl ether, anethole, diphenyl oxide, rose oxide, galaxolide, and ambrox; isopropyl alcohol, cis-3-hexenol, heptanol, 2-octanol, dimetol, dihydromyrcenol, linalool, benzyl alcohol, citronellol, and geraniol. alcohols such as nerol, terpineol, tetrahydrogeraniol, l-menthol, cedrol, santalol, thymol, anise alcohol, phenylethyl alcohol, and hexanol; ketones such as diacetyl, menthone, isomenthone, thiomenthone, acetophenone, α- or β-damascone, α- or β-damascenone, α-, β-, or γ-ionone, α-, β-, or γ-methylionone, methyl-β-naphthyl ketone, benzophenone, tentalome, acetyl cedrene, α- or β-isomethylionone, α-, β-, or γ-irone, maltol, ethyl maltol, cis-jasmone, dihydrojasmone, l-carvone, dihydrocarvone, and methyl amyl ketone; camphor, 1,8-cineole, allyl amyl glycolate, isopulegol, and allyl caproate. These fragrances may be used alone or in any combination of two or more to form a blended fragrance.Furthermore, the fragrance may be used as a mixture (fragrance composition) containing fragrance ingredients, solvents, fragrance stabilizers, etc.

Solvents for fragrances include, for example, water, alcohols such as ethanol, propanol, and benzyl alcohol, polyhydric alcohols such as ethylene glycol, diethylene glycol, dipropylene glycol, glycerin, and 1,3-butanediol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monoisobutyl ether, triethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol dimethyl ether, and dipropylene glycol. Examples of suitable solvents include glycol ethers such as propylene glycol monomethyl ether, tripropylene glycol monomethyl ether, tripropylene glycol monobutyl ether, propylene glycol monopropyl ether, dipropylene glycol monopropyl ether, propylene glycol monobutyl ether, propylene glycol tert-butyl ether, dipropylene glycol monobutyl ether, dipropylene glycol dimethyl ether, phenyl carbitol, phenyl cellosolve, and benzyl carbitol; paraffins such as n-paraffin; esters such as diethyl phthalate, benzyl benzoate, triethyl citrate, and isopropyl myristate; and others such as 3-methyl-4-methoxybutanol, N-methylpyrrolidone, and propylene carbonate. These solvents can be used alone or in any combination of two or more. They can also be mixed with the above-mentioned fragrance components to form fragrance compositions.

The expandable compression molded product of this embodiment preferably contains a fragrance component with a vapor pressure at 25°C (hereinafter sometimes simply referred to as vapor pressure) of 0.00002 to 120 mmHg, more preferably 0.001 to 120 mmHg, and even more preferably 0.1 to 120 mmHg. Fragrance components within this vapor pressure range are preferred because they are more likely to volatilize from the bathwater.

Fragrance ingredients with a vapor pressure of 0.00002 to 120 mmHg include, for example, limonene, pinene, myrcene, camphene, geraniol, citronellol, linalool, linalyl acetate, phenethyl acetate, isobornyl acetate, isoamyl acetate, amyl acetate, ethyl butyrate, ethyl vanillin, α-hexyl cinnamic aldehyde, ethyl acetate, tonalide, nerol, hexyl acetate, cineole, decanal, eugenol, borneol, indole, cresol, benzyl benzoate, butyl acetate, terpineol, γ-decalactone, δ-decalactone Examples include cyclohexyl ether, γ-dodecalactone, δ-dodecalactone, allylheptanoate, styrallyl acetate, citral, galaxolide, methyl dihydrojasmonate, isocyclocitral, bornyl acetate, butylcyclohexyl acetate, phenethyl acetate, triethyl citrate, vanillin, menthone, ambellone, 2-ethyl-4-(2,2,3-trimethyl-3-cyclopentenyl)-2-buten-1-ol, and the like. These can be used alone or in combination with two or more types, and may also be used in combination with fragrance components whose vapor pressure is outside the above range.

The vapor pressure of the above fragrance ingredients at 25°C is shown in Table 1 below.

Fragrance ingredients that are less soluble in water are preferable because this increases the persistence of the fragrance. If the fragrance ingredient is not easily soluble in water (bath water), when the bubbles pop near the water surface, the fragrance ingredient present around the bubbles will diffuse into the air, increasing the intensity of the fragrance.
From the viewpoint of fragrance persistence, the solubility of the fragrance component in water is preferably 100 mg/mL or less, more preferably 20 mg/mL or less, and even more preferably 2 mg/mL or less, and is preferably 0.000001 mg/mL or more, more preferably 0.001 mg/mL or more, and even more preferably 0.005 mg/mL or more.
The solubility of a fragrance component in water is an index showing how much of the fragrance component dissolves in water, and is expressed in mg as the mass of the fragrance component that dissolves in 1 mL of water at 25°C.
Among the fragrance ingredients listed above, ingredients with a solubility in water of 20 mg/mL or less include cineole (0.3321 mg/mL), limonene (0.00757 mg/mL), menthone (0.688 mg/mL), linalool (1.59 mg/mL), citral (0.59 mg/mL), terpineol (7.1 mg/mL), hexyl acetate (0.511 mg/mL), citronellol (0.2 mg/mL), nerol (0.531 mg/mL), geraniol (0.1 mg/mL), eugenol (2.46 mg/mL), vanillin (11.02 mg/mL), ethyl vanillin (2.822 mg/mL), galaxolide (0.00175 mg/mL), benzyl benzoate (0.0154 mg/mL), and butyl cyclohexyl acetate (0.003552 mg/mL).

The expandable compression-molded product of this embodiment preferably contains 0.1 to 2% by mass of the above-mentioned fragrance component, and more preferably 0.3 to 1% by mass.

(organic acid)
The expandable compression-molded product of the present embodiment preferably contains a component that generates carbon dioxide gas, such as a carbonate and an organic acid. Carbon dioxide gas can be generated by the reaction between the carbonate and the organic acid.

Examples of organic acids include succinic acid, fumaric acid, malic acid, adipic acid, tartaric acid, benzoic acid, citric acid, and salicylic acid. From the standpoints of ease of handling and economy, succinic acid or fumaric acid is preferred. These organic acids can be used alone or in combination of two or more.

Furthermore, from the viewpoints of tableting, granulation, solubility, and oil absorption capacity, the particle size (average particle size d50) of the organic acid is preferably 0.03 to 1 mm, and more preferably 0.05 to 0.5 mm. When the particle size of the organic acid is within the above range, it is less likely to remain undissolved in the liquid, and it is preferable because it foams efficiently and diffuses the fragrance of the fragrance.

If the particle size is larger than the above, it is preferable to crush it in advance to the appropriate particle size. Crushers that can be used for crushing include impact crushers such as hammer crushers, atomizers, impact crushers such as pin mills, and shear crushers such as flash mills. These can be used in a single-stage operation, or in a multi-stage operation using the same or different types of crushers.

The organic acid content in 100% by mass of the expandable compression molded product is preferably 10 to 65% by mass. If the organic acid content is 10% by mass or more, sufficient carbon dioxide gas can be generated when it reacts with carbonate to generate carbon dioxide gas. The organic acid content is more preferably 15% by mass or more, and even more preferably 20% by mass or more. Furthermore, from the perspective of suppressing undissolved organic acid, the organic acid content is preferably 65% by mass or less, more preferably 55% by mass or less, even more preferably 40% by mass or less, and particularly preferably 30% by mass or less. By keeping the content within the above range, it is possible to suppress choking caused by powder in the expandable compression molded product flying up due to foaming.

(carbonate)
The carbonate may be any that reacts with an organic acid in a liquid to generate carbon dioxide gas, and examples thereof include sodium carbonate, sodium bicarbonate, sodium sesquicarbonate, calcium carbonate, potassium carbonate, magnesium carbonate, etc. One or more of these may be used. Among these, it is more preferable to use sodium carbonate and sodium bicarbonate.

The carbonate content in 100% by mass of the expandable compression molded product is preferably 20 to 90% by mass. If the carbonate content is 20% by mass or more, sufficient carbon dioxide gas can be generated when reacting with an organic acid to generate carbon dioxide gas. The carbonate content is more preferably 30% by mass or more, and even more preferably 40% by mass or more. The carbonate content is also preferably 80% by mass or less, more preferably 75% by mass or less, and even more preferably 65% by mass or less. Within the above ranges, the amount of foaming per unit time can be increased, resulting in vigorous foaming and improved fragrance release.

The particle size (average particle size d50) of the carbonate is preferably 0.03 to 1 mm, and more preferably 0.05 to 0.5 mm. Within this range, the expandable compression-molded product will have an appropriate hardness and can maintain its expansion time (disintegration time).

(Other ingredients)
The expandable compression-molded product used in the embodiment of the present invention may contain other components as appropriate, even if they are not the components described above, as long as the problem of the present invention can be solved. Examples of other components include inorganic salts, sugars, lubricants, opacifiers, binders, humectants, surfactants, enzymes, colorants, pigments/minerals, vitamins and their derivatives, anti-fading agents, pH adjusters, and disinfectants. The uses of these other components may overlap.

Inorganic salts include any optional components other than the carbonates listed above, such as chlorides such as sodium chloride, potassium chloride, and ammonium chloride; sulfates such as sodium sulfate, aluminum sulfate, iron sulfate, aluminum potassium sulfate, sodium thiosulfate, calcium thiosulfate, potassium thiosulfate, and sodium hyposulfite; nitrates such as sodium nitrate, potassium nitrate, and calcium nitrate; phosphates such as sodium phosphate, sodium polyphosphate, and calcium hydrogen phosphate; silicates such as calcium silicate and magnesium silicate; sulfides such as sulfur, calcium sulfide, sodium sulfide, potassium sulfide, ammonium sulfide, barium sulfide, zinc sulfide, tin sulfide, antimony sulfide, iron sulfide, and phosphorus sulfide; silicon compounds such as metasilicic acid, mica powder, and neutral clay; hydroxides such as sodium hydroxide and calcium hydroxide; borax, boric acid, calcium oxide, potassium bromide, potassium permanganate, artificial callus salt, mineral springs, mineral sand, and hot spring deposits. These inorganic salts can also be included as bulk adjusters, formulation aids, and formulation stabilizers.

The content of inorganic salts in 100% by mass of the expandable compression-molded product is preferably 2.5% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more. It is also preferably 40% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less. By staying within the above range, the expandable compression-molded product will have excellent shape retention and good solubility.

Examples of sugars include glucose, fructose, lactose, maltose, sucrose, maltodextrin, cyclodextrin, maltose, fructose, and trehalose. The sugar content in 100% by mass of the expandable compression-molded product of this embodiment is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and even more preferably 0.5% by mass or more, and preferably 15% by mass or less, more preferably 10% by mass or less, and even more preferably 3% by mass or less. Within the above ranges, the expandable compression-molded product can have excellent shape retention and good solubility.

Examples of lubricants include talc, kaolin, magnesium stearate, calcium stearate, stearic acid, silicic anhydride, sucrose fatty acid ester, silicone oil, and liquid paraffin, with silicic anhydride, sucrose fatty acid ester, magnesium stearate, and liquid paraffin being preferred. The foaming time (disintegration time) of the expandable compression-molded product of this embodiment can be adjusted by adding a lubricant. For example, the foaming time (disintegration time) can be extended by increasing the amount of lubricant added.
The lubricant is preferably contained in an amount of 0.001 to 1.0% by mass, more preferably 0.01 to 0.5% by mass, relative to 100% by mass of the expandable compression-molded product. By containing the lubricant in the above range, the flowability of the raw materials can be improved when they are mixed.

Examples of opacifying agents include titanium oxide.

Examples of binders include polyalkylene glycol, polyvinylpyrrolidone, dextrin, etc. Among these, polyalkylene glycol is preferred.
The molecular weight of the polyalkylene glycol is preferably 100 to 20,000, more preferably 400 to 15,000, and even more preferably 2,000 to 10,000. Specifically, polyethylene glycol, polypropylene glycol, etc. are used, with polyethylene glycol being particularly preferred. Also, one or more of various polyalkylene glycols can be used in combination. By including a binder, the foaming time (disintegration time) of the expandable compression-molded product can be adjusted. For example, the foaming time (disintegration time) can be extended by increasing the amount of binder added.

Moisturizing agents include, for example, ceramides such as ceramide, ceramide derivatives, and ceramide analogues; organic acid salts such as sodium lactate, disodium tartrate, sodium pyrrolidonecarboxylate, and disodium glutamate; mucopolysaccharides such as chondroitin sulfate and hyaluronic acid; plant collagen obtained from soybeans, corn, carrots, etc.; marine collagen obtained from salmon, pufferfish, tuna, flounder, etc.; fatty acid esters such as isopropyl myristate and isopropyl palmitate, shea butter, squalane, placenta, arbutin, casein, silk, honey, jojoba oil, ginger extract, pueraria root extract, and cationized cellulose.

Examples of surfactants include nonionic surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene hydrogenated castor oil, polyoxyethylene polyoxypropylene copolymers, polyoxyethylene fatty acid esters, and sorbitan fatty acid esters; anionic surfactants such as fatty acid esters such as soap bases, sodium α-olefin sulfonate, sodium alkyl glucoside sulfate, sodium lauryl sulfate, polyoxyethylene sodium lauryl sulfate, and sodium coconut oil fatty acid methyl taurate; amphoteric surfactants such as alkyl betaines, alkylamidopropyl betaines, alkylamido sulfobetaines, and 2-alkyl-N-carboxymethyl-N-hydroxyethyl imidazolinium betaines; and cationic surfactants such as alkylamine salts and quaternary ammonium salts.

Enzymes include, for example, trypsin, α-chymotrypsin, bromelain, papain, protease, proctase, serratiopeptidase, lysozyme, pepsin, and ficin.

Examples of pigments include legal pigments such as Blue No. 1, Blue No. 2, Red No. 102, Red No. 106, Red No. 227, Red No. 230 (1), Yellow No. 4, Yellow No. 5, Yellow No. 202 (1), Green No. 3, Green No. 201, Green No. 204, and Orange No. 205, as well as chlorophyll, riboflavin, annatto, anthocyanins, etc.

Examples of pigments and minerals include clay, red iron oxide, yellow iron oxide, mica, zinc oxide, bentonite, zeolite, metasilicic acid, acid clay, and coated particles (granules) of these. These can also be included as formulation aids.

Examples of vitamins and their derivatives include vitamin A, vitamin B, vitamin C, vitamin D, vitamin E, vitamin F, vitamin H, pantothenic acid, nicotinic acid or its derivatives, vitamin E nicotinate, tocopherol acetate, sodium ascorbate, etc.

Examples of anti-fading agents include amino acids such as glycine, alanine, and glutamic acid, and their salts.

Examples of pH adjusters include disodium hydrogen phosphate, trisodium phosphate, disodium hydrogen citrate, and trisodium citrate.

Examples of disinfectants include isopropylmethylphenol, triclosan, dichloroisocyanuric acid, silver zeolite, cetylpyridinium chloride, benzalkonium chloride, benzothonium chloride, chlorhexidine, hinokitiol, phenol, glycyrrhizinate and its derivatives, etc.

(Method for producing expandable compression molded product)
The expandable compression molded product of this embodiment can be produced by mixing the above components and compression molding. When compressing, the method is not particularly limited as long as it can produce an expandable compression molded product, for example, a tablet, and a known tablet press can be used.
A tablet press is a device that fills a die with a powder mixture and compresses it between a lower punch and an upper punch to form a tablet. There are single-punch tablet presses, in which a pair of upper and lower punches move up and down inside a single die to compress the mixture, and rotary tablet presses, in which dies are embedded at equal intervals around the periphery of a horizontally rotating turntable, and a series of operations - filling, compression, and ejection - are carried out continuously as the turntable rotates.

When using a tablet press, the size, thickness and shape of the tablets are preferably adjusted to the size, thickness and shape of the expandable compression-molded product of this embodiment described above.
Furthermore, in order for the expandable compression molded product of this embodiment to have a concave portion on at least one of the top and bottom surfaces, it is preferable to use a tablet press in which at least one of the lower and upper punches has a convex portion of a shape corresponding to the concave portion of the expandable compression molded product, or to form a concave shape by scraping at least one of the top and bottom surfaces of the expandable compression molded product after molding.

From the viewpoint of moldability, the tableting pressure when using a tablet press is preferably 10 to 30 t, and more preferably 13 to 25 t. Tableting at a tableting pressure of 10 t or more prevents the tablets from becoming brittle and makes them less likely to crack or chip during line conveyance or transport. Furthermore, a tableting pressure of 30 t or less makes it less likely for capping to occur and makes it less likely for tablets to chip during line conveyance or transport.
Furthermore, the size, thickness and density of the tablets can be adjusted by changing the tableting pressure.

The compression molding method should not be limited, and production can be carried out using direct powder compression (direct compression) or granule compression (indirect compression). The order and method of mixing the components can be selected as appropriate.

The expandable compression molded product of this embodiment has a good fragrance and improves the persistence of the fragrance. Furthermore, by placing the expandable compression molded product of this embodiment so that the recessed side is in contact with the bottom of the water tank, the persistence of the fragrance of the fragrance can be improved.

Applications of the foamable compression molded product of this embodiment include, for example, bath additives, air fresheners, deodorizers, foaming cleaners such as denture cleaners, flush toilet cleaners, and drain cleaners, foaming confectionery, and head spa applications, with bath additives being preferred.

[Bath additives]
The bath additive of this embodiment is made of a foamable compression molded product having a recess and containing a fragrance. When such a bath additive is submerged in water, the generated gas is temporarily retained within the recess and bubbles with a diameter of 1 cm or more are released into the water. This improves the durability of the fragrance. The foamable compression molded product having a recess is preferably the foamable compression molded product of this embodiment. Furthermore, when the bath additive is submerged in water, it is preferable to place it so that the surface having the recess is in contact with the bottom of the aquarium.

Based on the above, the present specification discloses the following:
[1] A method for improving the persistence of a fragrance of a fragrance by using an expandable compression-molded product containing the fragrance,
The expandable compression-molded product has a top surface, a bottom surface, and a side surface,
At least one of the top surface and the bottom surface has a recess;
A method for improving the persistence of a fragrance, comprising placing the expandable compression-molded product so that the top surface having the recess or the bottom surface having the recess is in contact with the bottom of a water tank, and allowing the expandable compression-molded product to react with water.
[2] The method for improving the persistence of a fragrance according to [1], wherein the foamable compression molded product is a bath additive.
[3] A foamable compression molded product containing a fragrance,
The expandable compression-molded product has a top surface, a bottom surface, and a side surface,
The expandable compression-molded article, wherein the top surface and the bottom surface have recesses.
[4] The expandable compression molded product according to [3], which is a bath additive.
[5] The expandable compression molded product according to [3] or [4], wherein the volume of the recess is 2000 ^mm3 or more.
[6] A bath additive comprising a foamable compression molded product having a recess and containing a fragrance,
When the bath additive is submerged in water, the generated gas is temporarily retained in the recess, and bubbles with a diameter of 1 cm or more can be released into the water.

The present invention will be explained in more detail below using examples, but the present invention is not limited to these.

[Examples 1 to 4, Comparative Example 1]
A powder mixture was prepared by uniformly mixing the components according to the composition shown in Table 2. This powder mixture was compression-molded using a single-punch tablet press to produce cylindrical foamable compression-molded bath additives having the diameter, thickness, and recess volume shown in Table 3. The density of the foamed compression-molded products of Examples 1 to 4 and Comparative Example 1 was 1.7 g/ ^cm3 .
The recessed portion on the top surface was formed to a predetermined volume by scraping the surface of the expandable compression-molded product with a file, and the recessed portion on the bottom surface was formed by tableting using a lower punch having a convex portion.
The volume of the recesses was calculated from the mass and bulk density of the sodium sulfate filled in the recesses of the expandable compression molded product by filling the recesses with sodium sulfate (powder) having a known bulk density.
The fragrances shown in Table 2 are herbal fragrances whose main components are linalool, linalyl acetate, citronellol, butylcyclohexyl acetate, and limonene.

<Number of bubbles with a diameter of 1 cm or more and duration of occurrence>
The bath additives of Examples 1 to 4 and Comparative Example 1 were evaluated under the following conditions for the number of bubbles having a diameter of 1 cm or more that were generated and the duration of generation.
200 L of hot water (40°C) was placed in a bathtub, and one bath additive tablet was placed in the bathtub with the top side of the bath additive touching the bottom of the bathtub. Bubbles rising from the bath additive to the surface of the water were photographed every 10 seconds from above the surface of the water, and the number of bubbles 1 cm or larger in diameter that were generated every 10 seconds was counted, and the total number of bubbles 1 cm or larger in diameter that were generated until foaming ceased was counted.
The evaluation criteria are as follows:
[Evaluation criteria]
Total number of bubbles with a diameter of 1 cm or more ○: 50 or more △: 10 to 49 ×: 9 or less

The period during which one or more bubbles with a diameter of 1 cm or more appeared was also calculated.
The evaluation criteria are as follows:
[Evaluation criteria]
○: 60 seconds or more △: 10 seconds to 59 seconds ×: 9 seconds or less

<Fragrance intensity evaluation (after 2 hours)>
In a bathroom with an enclosed space of 3.74 ^m3 (1.6 m (length) x 1.2 m (width) x 1.95 m (height)), 200 L of hot water (40°C) was poured into the bathtub, and one bath additive tablet was added so that the top side of the bath additive was in contact with the bottom of the bathtub. After that, four expert panelists evaluated the fragrance intensity in the bathroom immediately after the entire amount of the bath additive had dissolved, and after 30 minutes, 1 hour, and 2 hours. The evaluation criteria were as follows:
[Evaluation criteria]
2 points: Almost no weakening immediately after dissolution 1 point: Slight weakening immediately after dissolution 0 point: Significant weakening immediately after dissolution The average of the evaluation results of each panelist was calculated. The evaluation criteria are as follows:
[Evaluation criteria]
Pass: 1 or more Fail: Less than 1

The results are shown in Table 3 and FIG.
The disintegration time in the table refers to the time required for the expandable compression-molded product to completely dissolve.

It was confirmed that the fragrance intensity was sufficient in all test examples of Examples 1 to 4 and Comparative Example 1 immediately after the entire amount of the bath additive was dissolved.
From the above results, it can be seen that in Examples 1 to 4, where the bath additive was placed so that the concave side of the bath additive was in contact with the bottom of the bathtub, the fragrance intensity was good even after 2 hours, and the fragrance persistence was improved. On the other hand, in Comparative Example 1, where the bath additive was placed so that the flat side was in contact with the bottom of the bathtub,
Although the fragrance intensity after 1 hour was within the acceptable standard, it was lower than that of Examples 1 to 4, and the fragrance intensity after 2 hours was significantly lower, and the fragrance persistence was not improved.
Furthermore, the expandable compression-molded products of Examples 1 to 4, which have recesses on both the top and bottom surfaces, maintained a good fragrance intensity even after two hours, and the fragrance persistence was improved. On the other hand, the expandable compression-molded product of Comparative Example 1, which has recesses on only one of the top and bottom surfaces, had a fragrance intensity after one hour that was within the acceptable standard, but was lower than that of Examples 1 to 4, and the fragrance intensity after two hours was significantly lower, and the fragrance persistence was not improved.
Furthermore, the bath additives of Examples 1 to 4, which were able to temporarily retain the generated gas within the recesses and release bubbles of 1 cm or more in diameter into the water, maintained a good fragrance intensity even after two hours, improving the persistence of the fragrance. On the other hand, the bath additive of Comparative Example 1, which did not generate bubbles of 1 cm or more in diameter, met the acceptable standard for fragrance intensity after one hour, but was lower than Examples 1 to 4, and after two hours the fragrance intensity was significantly lower, showing no improvement in persistence.

The results of Examples 1 to 4 show that good results can be obtained when the volume of the recess is 2000 mm ³ to 6000 mm ³ .

Furthermore, the results of Examples 1 to 4 showed that good results were obtained when the volume ratio of the recessed portion volume to the expandable compression-molded product volume [recessed portion volume/expandable compression-molded product volume] was 0.03 to 0.15.

Examples 5 to 7
Except for using the composition of the powder mixture shown in Table 4, cylindrical foamable compression-molded bath additives with the diameter, thickness, and recess volume shown in Table 5 were produced under the same conditions as in Example 1.
As in Example 1, the number of bubbles having a diameter of 1 cm or more that were generated, the duration of generation, and the fragrance intensity were evaluated.
The results are shown in Table 5 and FIG.

The above results show that even when the composition of the powder mixture was changed, the methods of Examples 5 to 7, in which the bath additives were placed so that the side with the recesses was in contact with the bottom of the bathtub, maintained good fragrance intensity even after two hours, and the fragrance persistence was improved. Furthermore, the expandable compression molded products of Examples 5 to 7, which have recesses on the top and bottom surfaces, maintained good fragrance intensity even after two hours, and the fragrance persistence was improved. Furthermore, the bath additives of Examples 5 to 7, which were able to temporarily retain the generated gas within the recesses and release bubbles of 1 cm or more in diameter into the water, maintained good fragrance intensity even after two hours, and the fragrance persistence was improved.

[Examples 8 to 13, Comparative Example 2]
Except for using the powder mixture with the composition shown in Table 6, cylindrical foamable compression-molded bath additives with the diameter, thickness, and recess volume shown in Table 7 were produced under the same conditions as in Example 1. The density of the foamed compression-molded products in Examples 8 to 13 and Comparative Example 2 was 1.7 g/ ^cm3 .
In addition, similarly to Example 1, the fragrance intensity was evaluated.
The results are shown in Table 7 and Figures 7-8.

The above results show that, according to the method of Examples 8 to 13, in which the bath additive was placed so that the side with the recessed portion was in contact with the bottom of the bathtub, the fragrance intensity remained good even after two hours, and the fragrance persistence was improved, even when the type of fragrance was changed. Furthermore, the foamable compression molded products of Examples 8 to 13, which have recessed portions on the top and bottom surfaces, maintained good fragrance intensity even after two hours, and the fragrance persistence was improved. Furthermore, the bath additives of Examples 8 to 13, which were able to temporarily retain the generated gas within the recessed portions and release bubbles of 1 cm or more in diameter into the water, maintained good fragrance intensity even after two hours, and the fragrance persistence was improved.

Furthermore, comparing Examples 8 to 10, Example 9, which contained limonene, was superior to Example 8, which contained geraniol, and Example 10, which contained linalool, in all fragrance intensity ratings after 30 minutes, 1 hour, and 2 hours. This is thought to be because limonene has a solubility of 0.00757 mg/mL, which is lower in water than geraniol and linalool, making it easier for linalool to diffuse when the bubbles burst. As shown in Examples 11 to 13, even at a mass of 80 g, Example 12, which contained limonene, was superior in fragrance intensity ratings to Example 11, which contained geraniol, and Example 13, which contained linalool.

On the other hand, in the method of Comparative Example 2, in which the flat side of the bath additive was placed in contact with the bottom of the bathtub, the fragrance intensity after one hour met the acceptable standard, but after two hours the fragrance intensity had dropped significantly, and the fragrance duration was not improved. Furthermore, in the foamable compression-molded product of Comparative Example 2, which had recesses on only one of the top and bottom surfaces, the fragrance intensity after one hour met the acceptable standard, but after two hours the fragrance intensity had dropped significantly, and the duration was not improved. Furthermore, in the bath additive of Comparative Example 2, which did not produce bubbles with a diameter of 1 cm or more, the fragrance intensity after one hour met the acceptable standard, but after two hours the fragrance intensity had dropped significantly, and the duration was not improved.

Examples 14 to 18
Except for using the composition of the powder mixture shown in Table 8, cylindrical foamable compression-molded bath additives with the diameter, thickness, and recess volume shown in Table 9 were produced under the same conditions as in Example 1.
As in Example 1, the number of bubbles having a diameter of 1 cm or more that were generated, the duration of generation, and the fragrance intensity were evaluated.
The fragrances shown in Table 8 are herbal fragrances whose main components are limonene, linalool, eugenol, cineole, and terpineol.
The results are shown in Table 9 and FIG.

The above results show that even when the composition of the powder mixture was changed, the methods of Examples 14 to 18, in which the bath additives were placed so that the side with the recesses was in contact with the bottom of the bathtub, maintained good fragrance intensity even after two hours, and the fragrance persistence was improved. Furthermore, the expandable compression molded products of Examples 14 to 18, which had recesses on the top and bottom surfaces, maintained good fragrance intensity even after two hours, and the fragrance persistence was improved. Furthermore, the bath additives of Examples 14 to 18, which were able to temporarily retain the generated gas within the recesses and release bubbles of 1 cm or more in diameter into the water, maintained good fragrance intensity even after two hours, and the fragrance persistence was improved.

The expandable compression molded product of this embodiment is useful for bath additives, air fresheners, deodorants, cleaning agents, effervescent sweets, head spa applications, etc.

100, 200... Expandable compression molded product 1... Top surface 11... Recess 12... Edge 13... Chamfered portion 2... Bottom surface 21... Recess 22... Edge 23... Chamfered portion 3... Side surface

Claims (5)

A bath additive comprising a foamable compression-molded product containing a fragrance, the foamable compression-molded product having a recess and a rim surrounding the entire periphery of the recess ,
a volume ratio of the volume of the recessed portion to the volume of the expandable compression-molded product [volume of recessed portion/volume of expandable compression-molded product] of 0.04 to 0.15 ;
When the bath additive is submerged in water, the generated gas is temporarily retained in the recess, and bubbles with a diameter of 1 cm or more can be released into the water. The bath additive according to claim 1, wherein the volume of the recess is 2000 ^mm3 or more. Contains organic acids,
3. The bath additive according to claim 1, wherein the organic acid content is 10 to 65% by mass. Contains carbonates,
3. The bath additive according to claim 1, wherein the carbonate content is 20 to 90% by mass. A method for improving the persistence of a fragrance by using a bath additive made of a foamable compression-molded product containing a fragrance, comprising:
The expandable compression-molded product has a recess and an edge portion surrounding the entire periphery of the recess ,
a volume ratio of the volume of the recessed portion to the volume of the expandable compression-molded product [volume of recessed portion/volume of expandable compression-molded product] of 0.04 to 0.15 ;
The method for improving the persistence of fragrance of the bath additive is such that when the bath additive is submerged in water, the gas generated is temporarily retained within the recess and bubbles having a diameter of 1 cm or more are released into the water.