Water-soluble unit dose articles

Abstract

This product achieves high cleaning performance while suppressing the generation of undissolved residue in water-soluble unit-dose products. [Solution] In the water-soluble unit dose article, granular material is held in a water-soluble resin substrate. The water-soluble unit dose article contains a water-soluble inorganic salt A, which includes one or more selected from sodium bicarbonate A1 and potassium carbonate A2, and a surfactant B.

Description

Technical Field

[0001] The present invention relates to water-soluble unit-dose articles.

Background Art

[0002] Techniques for configuring laundry detergents as water-soluble unit-dose articles are known (see, for example, Patent Document 1). In such water-soluble unit-dose articles, since consumers can directly put a water-soluble unit-dose article containing a certain amount of laundry detergent into a washing machine without measuring it themselves when using the laundry detergent, high convenience can be obtained in daily laundry.

[0003] In the water-soluble unit-dose article described in Patent Document 1, sodium carbonate is blended as an alkaline agent. As a result, in this water-soluble unit-dose article, the pH when dissolved in water increases, and the penetration action by the surfactant is enhanced. Therefore, high detergency can be obtained with this water-soluble unit-dose article.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, it has been found that in water-soluble unit-dose articles containing sodium carbonate, lumpy residues are likely to occur.

[0006] The present invention relates to a technique for achieving high detergency while suppressing the generation of residues in water-soluble unit-dose articles.

Means for Solving the Problems

[0007] In one embodiment of the present invention, a water-soluble unit-dose article contains granular material held within a water-soluble resin substrate. The water-soluble unit-dose article contains a water-soluble inorganic salt A, which includes one or more selected from sodium bicarbonate A1 and potassium carbonate A2, and a surfactant B. [Effects of the Invention]

[0008] According to the present invention, a water-soluble unit-dose article is provided in which the generation of undissolved residue is suppressed. [Brief explanation of the drawing]

[0009] [Figure 1] This figure schematically shows an example of the structure of a water-soluble unit-dose article according to one embodiment of the present invention. [Figure 2] This figure schematically shows other examples of the above-mentioned water-soluble unit-dose articles. [Modes for carrying out the invention]

[0010] The embodiments of the present invention will be described below. The present invention is not limited to the embodiments shown below, and various modifications can be made without departing from the spirit of the invention.

[0011] [Overall composition of water-soluble unit dose article W] A water-soluble unit-dose article W according to one embodiment of the present invention may be a unit-dose article of laundry detergent used for washing clothes and the like. The water-soluble unit-dose article W comprises a water-soluble resin substrate X and granular material Y. In the water-soluble unit-dose article W, the granular material Y is held in place by the water-soluble resin substrate X. The water-soluble unit-dose article W also contains a water-soluble inorganic salt A and a surfactant B. The water-soluble inorganic salt A and surfactant B are contained in at least one of the water-soluble resin substrate X and the granular material Y. The specific configuration of the water-soluble unit-dose article W will be described below.

[0012] [Water-soluble resin base X and granular material Y] The water-soluble resin substrate X is mainly composed of a water-soluble resin and, from the viewpoint of ease of manufacture, is preferably configured as a sheet extending in an in-plane direction perpendicular to the thickness direction. In the water-soluble resin substrate X, the content of the water-soluble resin is preferably 10% by mass or more from the viewpoint of shapeability. The water-soluble resin is defined as the resin in which no insoluble matter is visible after adding 1 g of the resin to a 1 liter glass beaker containing 500 g of ion-exchanged water at 30°C, placing a Teflon® stirring bar with a diameter of 10 mm (maximum diameter) and a total length of 8 cm, and stirring at 100 rpm for 30 minutes.

[0013] Examples of water-soluble resins usable for the water-soluble resin substrate X include polyvinyl alcohol (PVA), vinyl alcohol copolymers, polyvinylpyrrolidone, polyalkylene oxides, (modified) cellulose, (modified) cellulose ethers or esters or amides, polycarboxylic acids and their salts such as polyacrylate, maleic acid / acrylic acid copolymers, polyamino acids i.e., peptides, polyamides such as polyacrylamide, polysaccharides such as starch and gelatin, and natural rubbers such as xanthan gum and carragum. Vinyl alcohol copolymers include copolymers of vinyl alcohol with other monomers, such as ethylene and acrylic acid. For example, from the viewpoint of use as a water-soluble film forming a unit dose, the water-soluble resin is preferably selected from the group consisting of polyacrylate and water-soluble acrylate, methylcellulose, sodium carboxymethylcellulose, dextrin, ethylcellulose, hydroxyethylcellulose, maltodextrin, polymethacrylate, polyvinyl alcohol, vinyl alcohol copolymer, hydroxypropyl methylcellulose (HPMC), and combinations thereof. From a similar viewpoint, the water-soluble resin is more preferably selected from polyvinyl alcohol, vinyl alcohol copolymer, and hydroxypropyl methylcellulose. From a similar viewpoint, even more preferably, the water-soluble resin is polyvinyl alcohol, for example, Solbron, available from Aicello Corporation. Water-soluble resins that can be used for the water-soluble resin substrate X are, for example, described in U.S. Patent No. 6,995,126. From the viewpoint of effectively obtaining the effects of the present invention, it is preferable that the water-soluble resin substrate X contains polyvinyl alcohol.

[0014] Figure 1 is a schematic diagram showing an example of the structure of a water-soluble unit-dose article W. In the water-soluble unit-dose article W shown in Figure 1, the water-soluble resin substrate X is a water-soluble fiber structure composed of an aggregate of multiple water-soluble fibers. In the water-soluble unit-dose article W shown in Figure 1, the granular material Y is held between the water-soluble fibers that make up the water-soluble resin substrate X. As a result, in the water-soluble unit-dose article W, the water-soluble resin substrate X and the granular material Y are maintained as an integrated unit.

[0015] The water-soluble fiber structure used as the water-soluble resin substrate X can be composed of one or more water-soluble fabric materials selected from, for example, nonwoven and woven water-soluble fibers. The water-soluble resin substrate X may be configured as a laminate of multiple water-soluble fabric materials or as a folded water-soluble fabric material. Furthermore, in the water-soluble unit-dose article W, the granular material Y does not necessarily have to be held between the water-soluble fibers of the water-soluble resin substrate X; for example, some or all of the granular material Y may be held by adhering to the surface of the water-soluble resin substrate X. Also, as shown in Figure 2, in the water-soluble unit-dose article W, the granular material Y may be held by being contained in a bag-shaped water-soluble resin substrate X. In the water-soluble unit-dose article W shown in Figure 2, the water-soluble resin substrate X is configured as a flat bag, and the granular material Y is contained within the water-soluble resin substrate X. Note that Figure 2 shows the granular material Y inside the water-soluble resin substrate X by viewing it through the water-soluble resin substrate X.

[0016] In the water-soluble unit-dose article W, the water-soluble resin substrate X only needs to be composed mainly of a water-soluble resin and capable of holding granular material Y, and does not have to be a water-soluble fiber structure. For example, the water-soluble resin substrate X may be composed of one or more water-soluble films. In this case, the water-soluble unit-dose article W can be configured such that the granular material Y is attached to and held on the surface of the water-soluble resin substrate X, or that the granular material Y is contained and held in a bag-shaped water-soluble resin substrate X. Furthermore, the water-soluble resin substrate X can be a combination of a water-soluble fiber structure and a water-soluble film. In addition, the shape of the water-soluble resin substrate X is not limited to a sheet shape, but may be any three-dimensional shape.

[0017] A water-soluble film bag-shaped water-soluble resin substrate X can be manufactured by any suitable process known in the art, such as a known detergent pouch manufacturing process. Examples of pouch manufacturing processes are described in U.S. Patents 6,995,126, 7,127,874, 8,156,713, 7,386,971, 7,439,215, and U.S. Patent Application Publication 2009 / 199877.

[0018] In the water-soluble unit-dose article W, the granular material Y is composed of components other than those contained in the water-soluble resin base X. Each granular material Y may be composed of a single component, or it may be composed of a mixture or aggregation of multiple components. In the water-soluble unit-dose article W, the amount of granular material Y is preferably 5 g or more, more preferably 8 g or more, and even more preferably 10 g or more, from the viewpoint of obtaining the effect of the granular material Y more effectively (for example, from the viewpoint of improving washability if the granular material Y has washability), and preferably 48 g or less, more preferably 38 g or less, and even more preferably 28 g or less, from the viewpoint of economy and lightness. In addition, in the water-soluble unit-dose article W, the average particle diameter of the granular material Y is preferably 100 μm or more, more preferably 150 μm or more, even more preferably 200 μm or more, and from the viewpoint of improving solubility, preferably 800 μm or less, more preferably 750 μm or less, and even more preferably 700 μm or less. The average particle size of granular material Y is determined from the mass fraction based on the sieve mesh size after vibrating it for 5 minutes using a standard sieve specified in JIS Z 8801.

[0019] The preferred shape and size of each water-soluble unit-dose article W is not particularly limited, but for example, from the viewpoint of efficient packaging and ease of use, it is a quadrilateral shape, with the length of one side preferably being 1 cm to 10 cm, more preferably 2 cm to 9 cm, and even more preferably 3 cm to 8 cm. From the viewpoint of robustness and ease of handling, the thickness is preferably 0.2 cm to 4 cm, more preferably 0.4 cm to 3 cm, and even more preferably 0.6 cm to 2 cm. The mass of each water-soluble unit-dose article W is preferably 5 g or more, more preferably 8 g or more, even more preferably 10 g or more, and preferably 50 g or less, more preferably 40 g or less, and even more preferably 30 g or less.

[0020] [Water-soluble inorganic salt A] In the water-soluble unit-dose article W, a water-soluble inorganic salt A is added as an alkaline agent to obtain high cleaning performance against sebum and the like by improving the penetration action of surfactant B. The water-soluble inorganic salt A contains one or more selected from sodium bicarbonate A1 and potassium carbonate A2, and may also contain sodium carbonate A3. The inventors of this application have found that when only sodium carbonate A3, which is commonly used as an alkaline agent in general laundry detergents, is used, clumpy undissolved residue tends to occur.

[0021] The inventors of this invention hypothesized the mechanism of this phenomenon as follows: Initially, the heat generated by the dissolution of sodium carbonate A3 upon contact with water causes a rise in the water temperature, locally increasing the amount of dissolved sodium carbonate A3. This leads to a further rise in the water temperature, causing a chain reaction in which the dissolution of sodium carbonate A3 proceeds rapidly. As a result, the area near the particles becomes an environment with a high concentration of inorganic salts, making it easier for polymer salting-out and hydrate recrystallization to occur. Consequently, the granular particles Y adhere to each other, and it is thought that this results in the formation of undissolved clumps that are difficult to dissolve.

[0022] In contrast, as described above, the water-soluble unit-dose article W uses one or more selected from sodium bicarbonate A1 and potassium carbonate A2 as essential components as the water-soluble inorganic salt A, rather than sodium carbonate A3. Even when sodium carbonate A3 is used, it is used in combination with one or more selected from sodium bicarbonate A1 and potassium carbonate A2. In the water-soluble unit-dose article W, the formation of lumpy undissolved residue can be prevented by the action of one or more selected from sodium bicarbonate A1 and potassium carbonate A2.

[0023] More specifically, sodium bicarbonate A1 has the property of endothermic when it dissolves in water. Therefore, in the water-soluble unit-dose article W, the rise in water temperature is suppressed when sodium bicarbonate A1 dissolves in water because it endothermically absorbs heat. Consequently, even when sodium carbonate A3 is added to the water-soluble unit-dose article W, the heat generated when it dissolves in water is canceled out by the endothermic reaction of sodium bicarbonate A1, thus suppressing the formation of undissolved clumps.

[0024] Furthermore, within the range of 5-40°C, which is the expected water temperature during washing, the solubility of sodium carbonate A3 in water changes significantly, while the solubility of potassium carbonate A2 in water hardly changes. Therefore, even if the water temperature rises due to the heat generated by the dissolution of sodium carbonate A3, an increase in the amount of potassium carbonate A2 dissolved in water is unlikely. For this reason, it is thought that in water-soluble unit-dose article W, the salting out of polymers and the recrystallization of inorganic salt hydrates will not proceed easily, and the generation of clumpy undissolved material can be suppressed.

[0025] In the water-soluble unit-dose article W, it is preferable to have a high amount of water-soluble inorganic salt A to obtain high cleaning performance by improving the penetration action of surfactant B, and it is preferable that the amount of water-soluble inorganic salt A is not too high in order to suppress the generation of undissolved residue. From these viewpoints, in the water-soluble unit-dose article W, the total content of sodium bicarbonate A1, potassium carbonate A2, and sodium carbonate A3 is preferably 6% by mass or more and 30% by mass or less. Furthermore, the total content of sodium bicarbonate A1, potassium carbonate A2, and sodium carbonate A3 in the water-soluble unit-dose article W alone is preferably 2 grams or more, more preferably 2.4 grams or more, and even more preferably 2.7 grams or more. Furthermore, the total content of A1, A2, and A3 is preferably 7 grams or less, more preferably 6 grams or less, and even more preferably 5 grams or less.

[0026] Furthermore, in the water-soluble unit-dose article W, when sodium carbonate A3 is included, it is preferable that the amount of sodium bicarbonate A1 and potassium carbonate A2 is somewhat greater than the amount of sodium carbonate A3. Specifically, if the content of sodium bicarbonate A1 is a1, the content of potassium carbonate A2 is a2, and the content of sodium carbonate A3 is a3, then the mass ratio of the total content of sodium bicarbonate A1 and potassium carbonate A2 (a1+a2) to the content of sodium carbonate A3 a3, (a1+a2) / a3, is preferably 0.3 or more, more preferably 0.33 or more, even more preferably 0.5 or more, and even more preferably 0.8 or more. From the viewpoint of improving solubility, the larger (a1+a2) / a3 is, the better, and a3 may be 0. However, from the viewpoint of blending cost, (a1+a2) / a3 is preferably 3.0 or less, and more preferably 2.0 or less.

[0027] In addition, in the water-soluble unit-dose article W, the sodium bicarbonate A1, potassium carbonate A2, and sodium carbonate A3 that constitute the water-soluble inorganic salt A may be contained in either the water-soluble resin substrate X or the granular material Y, or they may be contained in both. Furthermore, the water-soluble inorganic salt A may contain alkaline water-soluble inorganic salts other than sodium bicarbonate A1, potassium carbonate A2, and sodium carbonate A3, as needed.

[0028] [Surfactant B] (Anionic surfactant) Surfactant B preferably contains an anionic surfactant to broaden the cleaning spectrum to remove mud particles and the like. In the water-soluble unit-dose article W, surfactant B more preferably contains a sulfate ester type surfactant, and even more preferably contains an alkyl ether sulfate and / or a salt thereof, in order to improve cleaning performance.

[0029] When surfactant B contains an anionic surfactant, the content of the anionic surfactant in the water-soluble unit dose article W is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 30% by mass or more, from the viewpoint of improving cleaning performance, and preferably 60% by mass or less, more preferably 50% by mass or less, and even more preferably 45% by mass or less, from the viewpoint of economic efficiency.

[0030] When surfactant B contains a sulfate ester type surfactant, the content of the sulfate ester type surfactant in the water-soluble unit dose article W is preferably 6.5% by mass or more, more preferably 13% by mass or more, even more preferably 20% by mass or more, from the viewpoint of improving cleaning performance, and preferably 40% by mass or less, more preferably 35% by mass or less, even more preferably 30% by mass or less, from the viewpoint of economic efficiency.

[0031] When surfactant B contains alkyl ether sulfate and / or its salt, the content of alkyl ether sulfate and / or its salt in the water-soluble unit-dose article W is preferably 5% by mass or more, more preferably 6.5% by mass or more, from the viewpoint of improving cleaning performance, and preferably 20% by mass or less, more preferably 15% by mass or less, from the viewpoint of economic efficiency.

[0032] Furthermore, surfactant B may contain alkyl sulfate esters and / or salts thereof. In this case, in the water-soluble unit dose article W, the content of alkyl sulfate esters or salts thereof is preferably 5% by mass or more, more preferably 6.5% by mass or more, from the viewpoint of improving cleaning performance, and preferably 20% by mass or less, more preferably 15% by mass or less, from the viewpoint of economic efficiency. The content of alkyl sulfate esters or salts thereof is preferably 5% by mass or more and 20% by mass or less, more preferably 6.5% by mass or more and 15% by mass or less, from the viewpoint of improving cleaning performance and economic efficiency.

[0033] When the sulfate ester type surfactant is a salt, examples of the salt of the sulfate ester type surfactant include inorganic salts such as sodium salt, potassium salt, ammonium salt, and magnesium salt, and organic salts such as monoethanolamine salt, diethanolamine salt, triethanolamine salt, and morpholine salt. The salt of the anionic surfactant is preferably an inorganic salt selected from alkali metal salts such as sodium salt and potassium salt, and alkaline earth metal salts such as magnesium salt, from the viewpoint of availability. From the viewpoint of improving solubility, alkali metal salts are more preferable, and from the viewpoint of economic efficiency, sodium salts are even more preferable.

[0034] The sulfate ester type surfactant is preferably a compound represented by the following general formula (1-1). R 1a -O-(AO) n -SO3M (1-1) (In the formula, R 1a (where A is an aliphatic hydrocarbon group having 10 to 18 carbon atoms, A is one or more alkylene groups selected from ethylene and propylene groups, n is a number between 0 and 20 representing the average number of moles of alkylene oxy groups AO, and M is a cation.)

[0035] In formula (1-1), R 1a The aliphatic hydrocarbon group is preferably 10 or more, more preferably 11 or more, even more preferably 12 or more, and preferably 18 or less, more preferably 16 or less, and even more preferably 14 or less. 1a is a linear or branched aliphatic hydrocarbon group, preferably a linear aliphatic hydrocarbon group, and more preferably a linear alkyl group.

[0036] In formula (1-1), AO is one or more alkylene oxy groups selected from ethylene oxy groups and propylene oxy groups. When AO contains both ethylene oxy and propylene oxy groups, the ethylene oxy and propylene oxy groups may be in the form of block bonds or random bonds. From the viewpoint of improving washability, it is preferable that AO is a group containing an ethylene oxy group.

[0037] In formula (1-1), n ​​is 0 or greater, preferably 20 or less, more preferably 16 or less, even more preferably 12 or less, even more preferably 8 or less, and even more preferably 4 or less, from the viewpoint of improving cleanability.

[0038] In formula (1-1), when AO contains a propyleneoxy group, the average number of moles of propyleneoxy groups is preferably 4 or less, more preferably 3 or less, and preferably 0 or more.

[0039] In formula (1-1), the average number of moles of propyleneoxy groups may be 0.

[0040] In formula (1-1), when AO contains ethyleneoxy groups, the average number of moles of ethyleneoxy groups is preferably 0 or more, preferably 10 or less, more preferably 5 or less, and even more preferably 4 or less.

[0041] In formula (1-1), M is preferably an alkali metal ion such as a hydrogen ion, sodium ion, or potassium ion, an alkaline earth metal (1 / 2 atom) ion such as a magnesium ion or calcium ion, or an organic ammonium ion. The organic ammonium salt may be a salt of an amine such as monoethanolamine, diethanolamine, or triethanolamine. M is preferably an alkali metal ion such as a sodium ion or potassium ion, or an alkanol ammonium ion such as a monoethanolammonium ion or a diethanolammonium ion, and more preferably a sodium ion.

[0042] Surfactant B is represented by formula (1-1), where n represents the (non-average) number of moles n1 (integer value) of alkylene oxy group AO, and n1 is 1 or greater, R 1a When M contains compound ES as described above, the content of compound ES in the water-soluble unit dose article W is preferably 5% by mass or more, more preferably 6.5% by mass or more, from the viewpoint of improving cleaning performance, and preferably 20% by mass or less, more preferably 15% by mass or less, from the viewpoint of economic efficiency.

[0043] Surfactant B is represented by formula (1-1), where n is 0 and R 1a When M contains the same compound AS as described above, the preferred embodiment of the content of compound AS in the water-soluble unit dose article W is the same as the content of the alkyl sulfate ester or its salt described above.

[0044] As anionic surfactants other than sulfate ester type surfactants, one or more selected from alkylaryl sulfonic acid type surfactants, alkane sulfonic acid type surfactants, olefin sulfonic acid type surfactants, alkyl sulfosuccinate type surfactants, sulfo fatty acid ester type surfactants, and fatty acids and their salts are preferred, one or more selected from alkylaryl sulfonic acid type surfactants, alkyl sulfosuccinate type surfactants, and fatty acids and their salts are more preferred, and one or more selected from alkylaryl sulfonic acid type surfactants, and fatty acids and their salts are even more preferred.

[0045] Furthermore, if an anionic surfactant other than a sulfate ester type surfactant is a salt, the salt of the anionic surfactant is the same as the salt of a sulfate ester type surfactant as described above.

[0046] Examples of anionic surfactants other than sulfate ester-type surfactants include one or more compounds selected from the compounds represented by the following general formulas (1-2), (1-3), and (1-4).

[0047] For anionic surfactants other than sulfate ester-type surfactants, from the viewpoint of improving cleaning performance, one or more selected from compounds represented by general formulas (1-2), (1-3), and (1-4) are preferred, and one or more selected from compounds represented by general formulas (1-2) and (1-3) are more preferred.

[0048] When the surfactant B contains a compound represented by the general formula (1-2), in the water-soluble unit-dose article W, the content of the compound represented by the general formula (1-2) is preferably 5% by mass or more, more preferably 6.5% by mass or more, still more preferably 10% by mass or more, from the viewpoint of improving detergency, and preferably 25% by mass or less, more preferably 20% by mass or less, from the viewpoint of economy.

[0049] R 2a -Φ-SO3M …(1-2) (In the formula (1-2), R 2a represents an alkyl group having 9 to 14 carbon atoms, Φ represents a phenylene group, and the carbon atom of R 2a bonded to the carbon atom of Φ is a secondary carbon atom, and M represents a cation. The sulfonic acid group is bonded to the ortho, meta or para position with respect to R 2a bonded to Φ.)

[0050] R 3a -COOM …(1-3) (In the formula (1-3), R 3a represents an alkyl group or alkenyl group having 9 to 17 carbon atoms, and M represents a cation.)

[0051] R 4a -CH(SO3M)COOR[[ID=३१]] 5a (1-4) (In the formula (1-4), R 4a represents an alkyl group having 8 to 18 carbon atoms, R 5a represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and M represents a cation.)

[0052] In the general formula (1-2), R 2a is an alkyl group having 9 or more, preferably 10 or more, and 14 or less, preferably 13 or less carbon atoms.

[0053] In general formula (1-2), M is preferably an alkali metal ion such as a hydrogen ion, sodium ion, or potassium ion, an alkaline earth metal (1 / 2 atom) ion such as a magnesium ion or calcium ion, or an organic ammonium ion. The organic ammonium salt may be a salt of an amine such as monoethanolamine, diethanolamine, or triethanolamine. M is preferably an alkali metal ion such as a sodium ion or potassium ion, or an alkanolammonium ion such as a monoethanolammonium ion or a diethanolammonium ion, and more preferably a sodium ion.

[0054] As compounds represented by general formula (1-2), p-alkylbenzenesulfonates with an alkyl group having 10 to 14 carbon atoms are preferred, and p-alkylbenzenesulfonate sodium salts with an alkyl group having 10 to 14 carbon atoms are more preferred. That is, compounds represented by general formula (1-1) are those in general formula (1-2), where R 2a Compounds in which C1 is an alkyl group having 10 to 14 carbon atoms and M is a sodium ion are preferred.

[0055] In general formula (1-3), R 3a The alkyl or alkenyl group has preferably 9 or more carbon atoms, more preferably 10 or more, even more preferably 11 or more, and preferably 17 or fewer carbon atoms, more preferably 15 or fewer, and even more preferably 13 or fewer carbon atoms. 3a The group can be one or more groups selected from a linear alkyl group, a branched alkyl group, a linear alkenyl group, and a branched alkenyl group, with a linear alkyl group being preferred.

[0056] In general formula (1-3), M is preferably an alkali metal ion such as a hydrogen ion, sodium ion, or potassium ion, an alkaline earth metal (1 / 2 atom) ion such as a magnesium ion or calcium ion, or an organic ammonium ion. The organic ammonium salt may be a salt of an amine such as monoethanolamine, diethanolamine, or triethanolamine. M is preferably an alkali metal ion such as a sodium ion or potassium ion, or an alkanolammonium ion such as a monoethanolammonium ion or a diethanolammonium ion, and more preferably a sodium ion.

[0057] The compound represented by general formula (1-3) is preferably one or more selected from lauric acid, myristic acid, isostearic acid, palmitic acid, isopalmitic acid, oleic acid and their salts, more preferably one or more selected from lauric acid, myristic acid, palmitic acid and their salts, and even more preferably one or more selected from lauric acid, myristic acid and their salts.

[0058] Compounds represented by general formula (1-3) are those in general formula (1-3) where R 3a Compounds in which C1 is an alkyl group having 11 to 15 carbon atoms and M is a cation are preferred, and compounds in which M is a hydrogen ion or a sodium ion are more preferred.

[0059] In general formula (1-4), R 4a is preferably an alkyl group having 8 or more carbon atoms, more preferably 10 or more, even more preferably 12 or more, and preferably 18 or fewer, more preferably 16 or fewer. In general formula (1-4), R 5a The alkyl group is preferably one or more carbon atoms, preferably five or fewer, more preferably four or fewer, and even more preferably three or fewer.

[0060] In general formula (1-4), M is preferably an alkali metal ion such as a hydrogen ion, sodium ion, or potassium ion, an alkaline earth metal (1 / 2 atom) ion such as a magnesium ion or calcium ion, or an organic ammonium ion. The organic ammonium salt may be a salt of an amine such as monoethanolamine, diethanolamine, or triethanolamine. M is preferably an alkali metal ion such as a sodium ion or potassium ion, or an alkanolammonium ion such as a monoethanolammonium ion or a diethanolammonium ion, and more preferably a sodium ion.

[0061] Compounds represented by general formula (1-4) include, in general formula (1-4), R 4a is an alkyl group having 11 or more carbon atoms and 14 or fewer carbon atoms, R 5a A sodium methyl ester salt of α-sulfo fatty acid is preferred, in which is a methyl group and M is a sodium ion.

[0062] (Nonionic surfactant) Surfactant B may contain a nonionic surfactant. From the viewpoint of improving cleaning performance, examples of nonionic surfactants include one or more selected from polyoxyalkylene alkyl or alkenyl ethers, alkyl (poly)glycosides (glycoside-type nonionic surfactants), sorbitan-based nonionic surfactants, compounds in which alkylene oxide is added between the ester bonds of long-chain fatty acid alkyl esters, fatty acid monoglycerides, and sucrose fatty acid esters.

[0063] As a nonionic surfactant, a nonionic surfactant containing an alkylene oxy group is preferred, and from the viewpoint of improving cleaning performance, a nonionic surfactant having an average number of added alkylene oxy groups of 1 to 30 is preferred. The alkylene oxy group is preferably one or more groups selected from alkylene oxy groups having 2 to 4 carbon atoms, and more preferably one or more groups selected from ethylene oxy groups and propylene oxy groups. From the viewpoint of improving cleaning performance against sebum stains, the average number of added alkylene oxy groups is preferably 1 or more, more preferably 6 or more, even more preferably 8 or more, and preferably 30 or less, more preferably 25 or less, even more preferably 20 or less, and even more preferably 15 or less.

[0064] When surfactant B contains a nonionic surfactant, the content of the nonionic surfactant in the water-soluble unit-dose article W is preferably 5% by mass or more, more preferably 6.5% by mass or more, from the viewpoint of improving cleaning performance, and preferably 20% by mass or less, more preferably 15% by mass or less, from the viewpoint of economic efficiency. The content of alkyl ether sulfate ester or its salt is preferably 5% by mass or more and 20% by mass or less, more preferably 6.5% by mass or more and 15% by mass or less, from the viewpoint of improving cleaning performance and economic efficiency.

[0065] Nonionic surfactants containing alkylene oxy groups, wherein the average number of added alkylene oxy groups is 1 or more and 30 or less, are preferably nonionic surfactants represented by the following general formula (2-1).

[0066] R 6a (CO) m O-(A 1a O) n -R 7a …(2-1) (In formula (2-1), R 6a R is an aliphatic hydrocarbon group having 8 to 18 carbon atoms, 7a is a hydrogen atom or a methyl group. CO is a carbonyl group, and m is a number, either 0 or 1. A 1a O is one or more alkylene groups selected from those with 2 to 4 carbon atoms. n is an alkylene oxy group A 1a(This is the average number of moles of oxygen, and is between 1 and 30.)

[0067] In general formula (2-1), R 6a The number of carbon atoms is preferably 8 or more, more preferably 10 or more, even more preferably 12 or more, and preferably 18 or less, more preferably 16 or less, and even more preferably 14 or less, from the viewpoint of improving cleansing performance against sebum. 6a This is an aliphatic hydrocarbon group, preferably one or more groups selected from alkyl groups and alkenyl groups.

[0068] In general formula (2-1), A 1a O is one or more alkylene oxy groups having 2 to 4 carbon atoms, preferably one or more alkylene oxy groups having 2 to 3 carbon atoms, more preferably an ethylene oxy group. 1a If oxygen contains multiple different alkylene oxy groups, these different alkylene oxy groups may be either block-type or random-type bonds.

[0069] In general formula (2-1), n ​​is 1 or more, preferably 6 or more, more preferably 8 or more, and 30 or less, preferably 25 or less, more preferably 20 or less, and even more preferably 15 or less, from the viewpoint of improving cleanability against sebum stains.

[0070] In general formula (2-1), m is preferably 0 from the viewpoint of improving cleaning performance.

[0071] In general formula (2-1), R 7a From the viewpoint of improving cleaning performance, hydrogen atoms are preferred.

[0072] Specific examples of nonionic surfactants that do not have an alkylene oxy group include one or more selected from sucrose fatty acid esters, glycerin fatty acid esters, sorbitan fatty acid esters, alkyl glycosides, and glyceryl monoethers.

[0073] (cationic surfactant) Furthermore, surfactant B may also contain a cationic surfactant. Examples of cationic surfactants include quaternary ammonium salt type surfactants. Cationic surfactants may have one or more effects selected from bactericidal action, antibacterial action, and disinfectant action. As a quaternary ammonium salt type surfactant cationic surfactant, one or more compounds selected from the compounds represented by the following general formula (3-1) and the compounds represented by the following general formula (3-2) are preferred.

[0074] [ka]

[0075] (In the formula, R 8a R is an aliphatic hydrocarbon group having 8 to 18 carbon atoms, 9a R is a group selected from aliphatic hydrocarbon groups having 8 to 18 carbon atoms, alkyl groups having 1 to 3 carbon atoms, and hydroxyalkyl groups having 1 to 3 carbon atoms. 10a and R 11a Each of these is independently selected from alkyl groups having 1 to 3 carbon atoms and hydroxyalkyl groups having 1 to 3 carbon atoms, X - It is an anion.

[0076] [ka]

[0077] (In the formula, R 12a R is an aliphatic hydrocarbon group having 8 to 18 carbon atoms, 13a and R 14a Each of these is independently selected from alkyl groups having 1 to 3 carbon atoms and hydroxyalkyl groups having 1 to 3 carbon atoms, X - It is an anion.

[0078] In general formula (3-1), R 8a The number of carbon atoms is preferably 9 or more, more preferably 10 or more, even more preferably 12 or more, and preferably 16 or less, from the viewpoint of improving cleanability.8a R is preferably an alkyl group or an alkenyl group, with alkyl groups being preferred. In general formula (3-1), 9a R is a group selected from aliphatic hydrocarbon groups having 8 to 18 carbon atoms, alkyl groups having 1 to 3 carbon atoms, and hydroxyalkyl groups having 1 to 3 carbon atoms. 9a However, if it is an aliphatic hydrocarbon group with 8 to 18 carbon atoms, R 9a From the viewpoint of improving cleaning performance, alkyl or alkenyl groups are preferably 8 or more, preferably 14 or less, and more preferably 12 or less, with alkyl groups being more preferred.

[0079] In general formula (3-1), R 10a and R 11a Each of these groups is independently selected from alkyl groups having 1 to 3 carbon atoms and hydroxyalkyl groups having 1 to 3 carbon atoms. 10a and R 11a Preferably, each of these groups is independently selected from alkyl groups having 1 to 3 carbon atoms. Examples of alkyl groups having 1 to 3 carbon atoms include methyl, ethyl, and propyl groups. Examples of hydroxyalkyl groups having 1 to 3 carbon atoms include hydroxymethyl, hydroxyethyl, and hydroxypropyl groups.

[0080] In general formula (3-1), X - It is an anion. Examples of anions include halogen ions and one or more anions selected from alkyl sulfate ions having 1 to 3 carbon atoms. Examples of halogen ions include chloride ions, bromide ions, and iodide ions. Examples of alkyl sulfate ions having 1 to 3 carbon atoms include methyl sulfate ions, ethyl sulfate ions, and propyl sulfate ions.

[0081] In general formula (3-2), R 12a R is an aliphatic hydrocarbon group having 8 to 18 carbon atoms. 12aThe number of carbon atoms is preferably 8 or more, more preferably 10 or more, even more preferably 12 or more, and preferably 18 or less, more preferably 16 or less, from the viewpoint of improving antibacterial properties. 12a The group is preferably an alkyl group or an alkenyl group, and more preferably an alkyl group.

[0082] In general formula (3-2), R 13a and R 14a Each of these groups is independently selected from alkyl groups having 1 to 3 carbon atoms and hydroxyalkyl groups having 1 to 3 carbon atoms. 13a and R 14a Preferably, each of these groups is independently selected from alkyl groups having 1 to 3 carbon atoms. Examples of alkyl groups having 1 to 3 carbon atoms include methyl, ethyl, and propyl groups. Examples of hydroxyalkyl groups having 1 to 3 carbon atoms include hydroxymethyl, hydroxyethyl, and hydroxypropyl groups.

[0083] In general formula (3-2), X - It is an anion. Examples of anions include halogen ions and one or more anions selected from alkyl sulfate ions having 1 to 3 carbon atoms. Examples of halogen ions include chloride ions, bromide ions, and iodide ions. Examples of alkyl sulfate ions having 1 to 3 carbon atoms include methyl sulfate ions, ethyl sulfate ions, and propyl sulfate ions.

[0084] Specific examples of compounds of general formula (3-2) include N-dodecyl-N,N-dimethyl-N-benzylammonium salt, N-tridecyl-N,N-dimethyl-N-benzylammonium salt, N-tetradecyl-N,N-dimethyl-N-benzylammonium salt, N-pentadecyl-N,N-dimethyl-N-benzylammonium salt, N-hexadecyl-N,N-dimethyl-N-benzylammonium salt, N-dodecyl-N,N-diethyl-N-benzylammonium salt, N-tridecyl-N,N-diethyl-N-benzylammonium salt, and N-tetradecyl-N,N-diethyl-N-benzylammonium salt. Examples include one or more compounds selected from ammonium salt, N-pentadecyl-N,N-diethyl-N-benzylammonium salt, N-hexadecyl-N,N-diethyl-N-benzylammonium salt, N-dodecyl-N-methyl-N-ethyl-N-benzylammonium salt, N-tridecyl-N-methyl-N-ethyl-N-benzylammonium salt, N-tetradecyl-N-methyl-N-ethyl-N-benzylammonium salt, N-pentadecyl-N-methyl-N-ethyl-N-benzylammonium salt, and N-hexadecyl-N-methyl-N-ethyl-N-benzylammonium salt.

[0085] The cationic surfactant is preferably one or more selected from benzalkonium chloride, dialkyldimethylammonium chloride, and alkyltrimethylammonium chloride. Benzalkonium chloride is preferably a compound represented by general formula (3-2). Dialkyldimethylammonium chloride, such as dioctyldimethylammonium chloride, and alkyltrimethylammonium chloride, such as dodecyltrimethylammonium chloride, are preferably compounds represented by general formula (3-1).

[0086] If surfactant B contains a cationic surfactant, the content of the cationic surfactant in the water-soluble unit-dose article W is preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 3% by mass or less, and may be greater than 0% by mass, from the viewpoint of economy and stability. From a similar viewpoint, the content of the cationic surfactant in the water-soluble unit-dose article W may be 0% by mass.

[0087] (Amphoteric surfactant) Furthermore, surfactant B may include an amphoteric surfactant. Examples of amphoteric surfactants include one or more selected from N-alkanoylaminopropyl-N,N-dimethylamine oxide, N-alkyl-N,N-dimethylamine oxide, N-alkanoylaminopropyl-N,N-dimethyl-N-carboxymethylammonium betaine, N-alkyl-N,N-dimethyl-N-carboxymethylammonium betaine, N-alkyl-N,N-dimethyl-N-sulfopropylammonium sulfobetaine, N-alkyl-N,N-dimethyl-N-(2-hydroxysulfopropyl)ammonium sulfobetaine, N-alkanoylaminopropyl-N,N-dimethyl-N-sulfopropylammonium sulfobetaine, and N-alkanoylaminopropyl-N,N-dimethyl-N-(2-hydroxysulfopropyl)ammonium sulfobetaine. In these, the alkanoyl group is, for example, lauroyl or myristyl. In these, the alkyl group is, for example, a lauryl group or a myristyl group.

[0088] In the water-soluble unit-dose article W, when an amphoteric surfactant is included, from the viewpoint of improving cleaning performance and foaming, the content of the amphoteric surfactant is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, even more preferably 0.3% by mass or more, and preferably 2% by mass or less, more preferably 1.5% by mass or less, and even more preferably 1.2% by mass or less.

[0089] In the water-soluble unit-dose article W, the surfactant B may be contained in either the water-soluble resin substrate X or the granular material Y, or in both, but from the viewpoint of improving solubility, it is preferably contained in the granular material Y.

[0090] [Other ingredients] In the water-soluble unit-dose article W, components other than the water-soluble inorganic salt A and surfactant B may be added as needed. For example, the water-soluble unit-dose article W may contain one or more selected from a rheological modifier, a chelating agent, a water-insoluble inorganic component, an anionic polymer, and water.

[0091] (Rheological modifier) In the water-soluble unit-dose article W, for example, a rheological modifier is added to prevent the generation of undissolved material due to gelation when the water-soluble unit-dose article W is dissolved in water. The water-soluble unit-dose article W preferably contains an alkoxylated amine as the rheological modifier, more preferably an alkoxylated polyamine, even more preferably an alkoxylated polyethyleneimine, and even more preferably an ethoxylated polyethyleneimine.

[0092] In the water-soluble unit-dose article W, if a rheological modifier is included, the content of the rheological modifier is preferably 0.5% by mass or more, more preferably 1% by mass or more, even more preferably 2% by mass or more, and from the viewpoint of ease of formulation, preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less.

[0093] In addition, in the water-soluble unit dose article W, the rheology modifier may be contained in either the water-soluble resin substrate X or the granular material Y, or it may be contained in both.

[0094] (Chelating agent) In water-soluble unit-dose article W, a chelating agent is added to enhance the action of surfactant B and improve cleaning performance. Specific examples of chelating agents include, for example, aminopolyacetic acids such as ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, and hydroxyethyliminodiacetic acid, or their salts; organic acids such as citric acid, lactic acid, tartaric acid, and malic acid, or their salts; 1-hydroxyethylidene-1,1-diphosphonic acid, diethylenetriaminepenta(methylenephosphonic acid), and alkali metal or lower amine salts thereof; one or more of these can be used. Examples of chelating agent salts include alkali metal salts such as sodium salts and potassium salts; and lower amine salts such as monoethanolamine, diethanolamine, and triethanolamine.

[0095] In the water-soluble unit-dose article W, if a chelating agent is included, from the viewpoint of improving washability, the chelating agent content is preferably 0.5% by mass or more, more preferably 1.0% by mass or more, and even more preferably 2.0% by mass or more. From the viewpoint of ease of formulation, it is preferably 10% by mass or less, more preferably 8% by mass or less, and even more preferably 6% by mass or less.

[0096] (Water-insoluble inorganic components) The water-insoluble inorganic component may be a water-insoluble carrier. "Water-insoluble" in the context of the water-insoluble inorganic component means that 1 g or more of it does not dissolve in 100 g of water at 20°C. The water-insoluble inorganic component may be one or more selected from amorphous silica, calcium silicate, clay minerals, crystalline aluminosilicate, and amorphous aluminosilicate, preferably one or more selected from clay minerals and crystalline aluminosilicate. By using the water-insoluble inorganic component in a specific ratio with water-soluble inorganic salt A, it has the effect of suppressing undissolved residue after washing objects with water-soluble unit-dose article W and reducing turbidity of the rinse water.

[0097] The average primary particle size of the water-insoluble inorganic component is preferably 0.1 μm or more, more preferably 1 μm or more, and preferably 10 μm or less, and more preferably 5 μm or less. The average primary particle size of the water-insoluble inorganic component was measured using a laser diffraction / scattering particle size distribution analyzer (e.g., HORIBA LA-950). This average primary particle size is the D50 (median diameter) of the cumulative particle size distribution based on volume.

[0098] Examples of water-insoluble inorganic components include amorphous aluminosilicates (oil absorption capacity: 285 mL / 100 g) as described in Japanese Patent Publication No. 9-132794, Japanese Patent Publication No. 7-10526, Japanese Patent Publication No. 6-227811, and Japanese Patent Publication No. 8-119622.

[0099] More specifically, as the water-insoluble inorganic component calcium silicate, Fluorite R (manufactured by Tokuyama Corporation, oil absorption capacity: 400-500 mL / 100 g) can be used; as the water-insoluble inorganic component amorphous silica, Toxil NR (manufactured by Tokuyama Corporation, oil absorption capacity: 210-270 mL / 100 g) and Silopure (manufactured by Fuji Silicia Chemical Co., Ltd., oil absorption capacity: 240-280 mL / 100 g) can be used; and as the water-insoluble inorganic component amorphous aluminosilicate, TIXOREX25 (manufactured by Hanfutsu Chemical Co., Ltd., 220-270 mL / 100 g) can be used.

[0100] Furthermore, crystalline aluminosilicates include zeolites. Specific examples of zeolites include crystalline aluminosilicates such as type A, type X, and type P zeolites. Among crystalline aluminosilicates, type A zeolite (e.g., trade name "Toyobuilder": manufactured by Tosoh Corporation, oil absorption capacity according to JIS K 5101: 40 mL / 100 g or more) is preferred. Other preferred types include type P (e.g., trade names "Doucil A24", "ZSEO64", etc.; both manufactured by Crosfield; oil absorption capacity 60-150 mL / 100 g), type X (e.g., trade name "WessalithXD"; manufactured by Degussa; oil absorption capacity 80-100 mL / 100 g), and hybrid zeolites described in International Publication No. 98 / 42622.

[0101] Examples of water-insoluble inorganic clay minerals include bentonite. Bentonite with an ion exchange capacity of 50 to 100 meq / 100g is preferred. Bentonite can be one or more selected from the group consisting of alkali metal or alkaline earth metal montmorillonite, saponite, or hectorite (smectitic clay), illite, attapulgite, and kaolinite. Bentonite can be used in powdered or granular form. For example, refer to Japanese Patent Publication No. 2008-189719 for granulated clay minerals.

[0102] In the water-soluble unit-dose article W, the water-insoluble inorganic component may be contained in either the water-soluble resin substrate X or the granular material Y, or in both, but from the viewpoint of ease of manufacture, it is preferably contained in the granular material Y.

[0103] (Anionic polymer) Examples of anionic polymers include polymers having a carboxylic acid group or a salt thereof and having a weight-average molecular weight of 3,000 or more. Examples of anionic polymers include one or more polymers selected from polyacrylic acid and its salts, copolymers of acrylic acid and maleic acid and their salts, and polymaleic acid and its salts.

[0104] Examples of polyacrylic acid and its salts include one or more selected from polyacrylic acid, sodium polyacrylate, and potassium polyacrylate, and preferably one or more selected from sodium polyacrylate and potassium polyacrylate.

[0105] Examples of acrylic acid-maleic acid copolymers and their salts include one or more selected from acrylic acid-maleic acid copolymers, sodium salts of acrylic acid-maleic acid copolymers, and potassium salts of acrylic acid-maleic acid copolymers, and preferably one or more selected from sodium salts of acrylic acid-maleic acid copolymers and potassium salts of acrylic acid-maleic acid copolymers. The molar ratio of the acrylic acid-maleic acid copolymer is preferably 1 / 99 or more, more preferably 10 / 90 or more, and preferably 99 / 1 or less, and more preferably 90 / 10 or less, as the number of moles of acrylic acid / the number of moles of maleic acid.

[0106] Examples of polymaleic acid and its salts include one or more selected from polymaleic acid, sodium polymaleate, and potassium polymaleate, and preferably one or more selected from sodium polymaleate and potassium polymaleate.

[0107] The anionic polymer may be a copolymer containing monomers other than acrylic acid and maleic acid that are copolymerizable with acrylic acid and / or maleic acid, as long as this does not hinder the expression of the effects of the present invention. Examples of monomers other than acrylic acid and maleic acid that are copolymerizable with acrylic acid and / or maleic acid include one or more selected from vinyl monomers, acrylic monomers, and styrene monomers, and more specifically, one or more selected from methacrylic acid, methyl acrylate, ethyl acrylate, methyl methacrylate, and styrene. The molar ratio of monomers other than acrylic acid and maleic acid that are copolymerizable with acrylic acid and / or maleic acid in the anionic polymer is preferably 0 mol% or more, preferably 5 mol% or less, more preferably 3 mol% or less, and even more preferably 0 mol% in the anionic polymer. Accordingly, the polyacrylic acid and its salts, the copolymer of acrylic acid and maleic acid and its salts, and the polymaleic acid and its salts of the present invention may be polymers or copolymers that, in the total constituent monomers, contain monomers other than acrylic acid and maleic acid that are copolymerizable with acrylic acid and / or maleic acid in an amount of 0 mol% to 5 mol%.

[0108] The weight-average molecular weight of the anionic polymer is preferably 3,000 or more, more preferably 3,500 or more, even more preferably 4,000 or more, even more preferably 5,000 or more, even more preferably 6,000 or more, even more preferably 7,000 or more, even more preferably 8,000 or more, even more preferably 9,000 or more, even more preferably 10,000 or more, and preferably 100,000 or less, more preferably 50,000 or less, even more preferably 25,000 or less, and even more preferably 15,000 or less. This weight-average molecular weight can be measured according to the weight-average molecular weight measurement method described below.

[0109] The weight-average molecular weight of anionic polymers can be measured by GPC (gel permeation chromatography), and the weight-average molecular weight (Mw) can be determined using a conversion standard. The GPC measurement conditions are shown below. ·column: Manufactured by Tosoh Corporation, Product name: TSK-GEL guard PWXL Manufactured by Tosoh Corporation, Product name: TSK-GEL G4000 PWXL Manufactured by Tosoh Corporation, Product name: TSK-GEL G2500 PWXL Mobile phase: 0.1 mol / L potassium dihydrogen phosphate and 0.1 mol / L sodium dihydrogen phosphate aqueous solutions / acetonitrile = 90 / 10 (volume ratio) • Detector: Differential refractive index detector Column temperature: 40°C ·Flow rate: 1.0mL / min • Conversion reference material: Polyacrylic acid (manufactured by American Standard Corporation) • Sample: An aqueous polymer solution containing 0.8 g of solids is mixed with deionized water to prepare a total volume of 200 mL. 10 μL of this prepared solution is then taken and injected into the column.

[0110] In addition, in the water-soluble unit-dose article W, the anionic polymer may be contained in either the water-soluble resin substrate X or the granular material Y, or it may be contained in both.

[0111] (water) Water may be added to the water-soluble unit-dose article W. Examples of water include ion-exchanged water, purified water, and distilled water. The water also includes water used to add the components of the water-soluble unit-dose article W. In the water-soluble unit-dose article W, water may be contained in either the water-soluble resin substrate X or the granular material Y, or in both.

[0112] [Examples and Comparative Examples] The following describes embodiments of the present invention, but the present invention is not intended to be limited to these embodiments.

[0113] (Components) The following materials were used in Examples 1-22 and Comparative Examples 1 and 2. • LAS: Sodium laurylbenzenesulfonate "Neoperex G-65" (manufactured by Kao Corporation) AES: Sodium polyoxyethylene (2) lauryl ether sulfate (average number of moles of oxyethylene groups is 2, containing 30% by mass of sodium lauryl sulfate) • AS: Sodium lauryl sulfate "Emal 10G" (manufactured by Kao Corporation) AEO(10): Polyoxyethylene(10) lauryl ether (average number of moles of oxyethylene groups: 10) • Sodium carbonate: Light ash (bulk density 600 g / L, average particle size 100 μm, manufactured by Central Glass Co., Ltd.) • Sodium bicarbonate: Sodium bicarbonate (manufactured by AGC Inc.) • Potassium carbonate: Potassium carbonate (manufactured by AGC Inc.) • Sodium citrate: Trisodium citrate (crystalline, manufactured by Showa Chemical Co., Ltd.) • PEI-EO: Ethoxylated polyethyleneimine "Sokalan HP 20" (manufactured by BASF) • Silica: "Toxeal NR" (average particle size 181 μm, manufactured by Oriental Silicas Corporation) • Zeolite: "Zeobuilder" (Type 4A, average particle size 3.5 μm, manufactured by ZEOBUILDER)

[0114] (Examples 1-11 and Comparative Example 1) In Examples 1-11 and Comparative Example 1, powder samples of detergent compositions were prepared, consisting of components other than the water-soluble resin, which is the main component of the water-soluble resin substrate in the water-soluble unit-dose article. Table 1 shows the types of components (materials) blended and the content of each component (amount of effective portion of each material) (mass%) for the powder samples related to Examples 1-11 and Comparative Example 1.

[0115] [Table 1]

[0116] Specifically, a slurry-like detergent composition was prepared by uniformly mixing LAS, AES, and PEI-EO, then adding light ash and sodium bicarbonate and stirring. The obtained slurry-like detergent composition was dried in an electric dryer at a set temperature of 105°C for 5 hours, and the resulting dried material was pulverized using a mortar and pestle to obtain dried particles. AS and trisodium citrate were mixed with these dried particles, then silica was added and stirred, followed by the addition of silica supported with polyoxyethylene alkyl ether and stirring, and finally zeolite was added and stirred to obtain a powder sample of the detergent composition.

[0117] A cold water temperature change test was performed on the powder samples related to Examples 1 to 11 and Comparative Example 1. In the cold water temperature change test, 10 g of the powder sample was placed in a screw tube No. 7 (manufactured by Maruemu Co., Ltd.), and the tip (bulb) of a thermometer was inserted into the center of the powder sample and fixed in place. 40 mL of tap water cooled to 5°C was added all at once, and the temperature change of the water was measured over time, with the moment the tap water was added being set to 0 seconds. Furthermore, the temperature of the water 120 seconds after adding the tap water was set to t (°C), the temperature before adding the tap water was set to t0 (°C) (= 5°C), the specific heat capacity of water was set to c (J / g·°C) (= 4.18 J / g·°C), the amount of tap water was set to w (mL) (= 40 mL), and the amount of powder sample was set to p (g) (= 10 g), and the calorific value H (kJ / kg) was calculated using the following formula (1). H = (t - t0) × c × w / p …(1)

[0118] Table 2 shows the evaluation results of the cold water temperature change test for the powder samples of Examples 1-11 and Comparative Example 1, specifically the temperature t (°C) and calorific value H (kJ / kg) of the powder samples 120 seconds after tap water was added. Table 2 also shows the mass ratio a1 / a3 of sodium bicarbonate A1 content to sodium carbonate A3 content a3, and the mass ratio a2 / a3 of potassium carbonate A2 content to sodium carbonate A3 content a3 for the powder samples of Examples 1-8 and Comparative Example 1.

[0119] [Table 2]

[0120] As shown in Table 2, in the powder samples of Examples 1 to 8, where the mass ratio of the total content of sodium bicarbonate A1 and potassium carbonate A2 (a1+a2) to the content of sodium carbonate A3 a3 (a1+a2) / a3 was 0.3 or higher, a significant reduction in temperature t and the heat generated therefrom was observed compared to the powder sample of Comparative Example 1, which contained only sodium bicarbonate A3 as the water-soluble inorganic salt. Furthermore, in the powder samples of Examples 9 to 11, which contained only sodium bicarbonate A1 or potassium carbonate A2 as the water-soluble inorganic salt, the temperature t and the heat generated therefrom were further reduced.

[0121] (Examples 12-22 and Comparative Example 2) In Examples 12-22 and Comparative Example 2, powder samples (13.3g) from Examples 1-11 and Comparative Example 1 were placed in 7.5cm x 7.5cm rectangular flat bags (0.7g) made from polyvinyl alcohol (PVA) nonwoven fabric (manufactured by WBLLGG) to prepare water-soluble unit-dose article samples (14g). Table 3 shows the types of components, including the PVA constituting the nonwoven fabric, and the content (mass%) of each component for the article samples from Examples 12-22 and Comparative Example 2.

[0122] [Table 3]

[0123] The article samples from Examples 12-22 and Comparative Example 2 were evaluated for their solubility in a washing machine. In the washing machine solubility evaluation, the solubility of each article sample was evaluated based on the size of the residue of the article sample that remained undissolved after washing. Specifically, first, a first garment consisting of four sets each of trousers (UNIQLO), sweatshirts (UNIQLO), boxer shorts (UNIQLO), socks (UNIQLO), and long-sleeved shirts (HEATTECH, UNIQLO) was prepared, and a second garment consisting of cotton shirts (YG, Gunze) in an amount that made up to 8.0 kg in total weight with the first garment was prepared. One article sample packaged in a water-soluble film was placed into a drum-type washing machine (NA-VG1000L, Panasonic), followed by the 8.0 kg total weight of the first and second garments prepared earlier. Washing was performed with tap water (Wakayama City water) heated to 5°C on a standard course, with a wash cycle of 9 minutes, one rinse, and a spin cycle of 6 minutes. After the washing was complete, all of the first and second garments that had been washed were visually inspected, and any remaining residue from the undissolved material samples was collected. The diameter (mm) of the collected residue was measured using calipers.

[0124] For each item sample, an evaluation value for undissolved residue was determined based on the following indicators 1-5. In the washing machine residue evaluation, a higher evaluation value indicates better solubility of the item sample. 5: No undissolved residue was found at all. 4: 1 to 5 residues measuring between 1 mm and 5 mm were identified. 3: Six or more residues measuring between 1 mm and 5 mm were identified. 2: Residues measuring between 5mm and 20mm were detected. Residues larger than 1:20 mm were detected.

[0125] Table 4 shows the evaluation results of the washing machine residue test for the article samples related to Examples 12-22 and Comparative Example 2. Table 4 also shows the mass ratio a1 / a3 of sodium bicarbonate A1 content a3 to sodium carbonate A3 content a3, and the mass ratio a2 / a3 of potassium carbonate A2 content a2 to sodium carbonate A3 content a3.

[0126] [Table 4]

[0127] As shown in Table 4, the article samples from Examples 12 to 19, in which the mass ratio (a1+a2) / a3 of the total content of sodium bicarbonate A1 and potassium carbonate A2 to the content a3 of sodium carbonate A3 was 0.3 or higher, showed superior solubility compared to the article sample from Comparative Example 2, which contained only sodium bicarbonate A3 as the water-soluble inorganic salt. Furthermore, particularly excellent solubility was obtained in the article samples from Examples 14 and 15, in which the ratio a1 / a3 of the content a1 of sodium bicarbonate A1 to the content a3 of sodium carbonate A3 was 0.8 or higher, in the article sample from Example 19, in which the mass ratio a2 / a3 of the content a2 of potassium carbonate A2 to the content a3 of sodium carbonate A3 was 1.0 or higher, and in the article samples from Examples 20 to 22, which contained only sodium bicarbonate A1 or potassium carbonate A2 as the water-soluble inorganic salt. [Explanation of Symbols]

[0128] W...Water-soluble unit dose article X…Water-soluble resin base Y...granular

Claims

1. A water-soluble unit-dose article in which granular material is held in a water-soluble resin substrate, A water-soluble inorganic salt A containing one or more selected from sodium bicarbonate A1 and potassium carbonate A2, Surfactant B and A water-soluble unit-dose article containing the following.

2. The water-soluble inorganic salt A further comprises sodium carbonate A3. The water-soluble unit dose article according to claim 1.

3. The total content of sodium bicarbonate A1, potassium carbonate A2, and sodium carbonate A3 is 6% by mass or more and 30% by mass or less. The water-soluble unit dose article according to claim 2.

4. The total content of sodium bicarbonate A1, potassium carbonate A2, and sodium carbonate A3 is 2 grams or more. The water-soluble unit dose article according to claim 2.

5. The mass ratio of the total content of sodium bicarbonate A1 and potassium carbonate A2 to the content of sodium carbonate A3 is 0.3 or higher. The water-soluble unit dose article according to claim 2.

6. The surfactant B includes a sulfate ester type surfactant. The water-soluble unit dose article according to claim 1.

7. The content of the aforementioned sulfate ester-type surfactant is 6.5% by mass or more. The water-soluble unit dose article according to claim 6.

8. The water-soluble resin substrate is composed of one or more selected from water-soluble fiber structures and water-soluble films. The water-soluble unit dose article according to claim 1.

9. This is a unit-dose product of laundry detergent. A water-soluble unit-dose article according to any one of claims 1 to 8.

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