Water-soluble film for detergent packaging capsule, and detergent packaging capsule

Abstract

The purpose of the present invention is to provide a water-soluble film for a detergent packaging capsule, said film being capable of preventing sorbitol from precipitating on the surface of the film during long-term storage even when the film is a water-soluble film in which sorbitol is blended as a plasticizer. A water-soluble film for detergent packaging capsules, which contains an anionic group-modified polyvinyl alcohol resin, and which contains a plasticizer that contains sorbitol and a polymer comprising polyethylene glycol and / or polyglycerol, the content of the plasticizer being 100 parts by mass per 100 parts by mass of the anionic group-modified polyvinyl alcohol resin, and the content of the plasticizer being 100 parts by mass per 100 parts by mass per 100 parts by mass per 100 parts by mass per 100 parts by mass per 100 parts by mass of the anionic group-modified polyvinyl alcohol resin. And a plasticizer containing 6-15 parts by mass of the sorbitol and 3-15 parts by mass of the polymer, and the total content of the plasticizer being 25-50 parts by mass.

Description

TECHNICAL FIELD

[0001] The present application relates to a water-soluble film for a detergent packaging capsule and a detergent packaging capsule. BACKGROUND

[0002] As a detergent packaging capsule that encloses a powder detergent or a liquid detergent such as a laundry detergent, a dishwashing detergent, a household care composition, and the like, a packaging capsule formed by adhering a prescribed portion of a water-soluble film that takes polyvinyl alcohol resin as a main component is used. The packaging capsule that encloses a detergent, for example, in the case of being used for laundry, at least a part is dissolved in water at the start of laundry to release the detergent to form a washing liquid. During the laundry process, the packaging capsule is dissolved in the washing liquid, and after the end of the laundry, it is discharged together with the washing liquid.

[0003] For such a water-soluble film for a detergent packaging capsule, as described in Patent Document 1 below, in order to impart moderate softness to the film, make the processing such as vacuum forming (thermoforming) at the time of manufacturing the detergent packaging capsule easy to perform, a plasticizer such as sorbitol is contained. Also, the detergent packaging capsule formed of the water-soluble film containing sorbitol as a plasticizer and enclosing a powder detergent can prevent bag breakage caused by film embrittlement due to migration of the plasticizer into the powder detergent.

[0004] However, in order to achieve the molding processability of the water-soluble film for a detergent packaging capsule and prevent bag breakage of the detergent packaging capsule enclosing a powder detergent, in the case where a large amount of a plasticizer of sorbitol is incorporated in the water-soluble film, when stored in a film shape, the sorbitol can be precipitated onto the surface of the film to impair the appearance, and thus, there is a case where it is necessary to shorten the storage period thereof. Also, it has been confirmed that when the plasticizer such as sorbitol of the water-soluble film is reduced, in the detergent packaging capsule enclosing a liquid detergent, the tension of the film forming the capsule sometimes decreases.

[0005] PRIOR ART DOCUMENTS

[0006] PATENT DOCUMENTS

[0007] Patent Document 1: International Publication No. 2017 / 043510 SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] The present application has been achieved in order to solve the above-described problems, and has an object to provide a water-soluble film for a detergent packaging capsule and a detergent packaging capsule, which can prevent sorbitol from being precipitated onto the surface of the film during long-term storage even if the water-soluble film is combined with sorbitol or the like as a plasticizer, and which can maintain the tension feeling of the film forming the detergent packaging capsule even if the detergent packaging capsule is filled with a liquid detergent.

[0010] Solution to the problem

[0011] A water-soluble film for a detergent packaging capsule, which can achieve the above-described object, contains an anion group-modified polyvinyl alcohol resin, characterized in that the water-soluble film contains a plasticizer, the plasticizer includes sorbitol and a polymer formed from polyethylene glycol and / or polyglycerol, the content of the sorbitol is 6 to 15 parts by mass and the content of the polymer is 3 to 15 parts by mass, with respect to 100 parts by mass of the anion group-modified polyvinyl alcohol resin, and the content of the plasticizer is 25 to 50 parts by mass.

[0012] In the water-soluble film, it is preferable that the modification type of the anion group-modified polyvinyl alcohol resin is maleic acid modification and the modification degree is 0.5 to 6.0 mol%, whereby the solubility of the detergent packaging capsule in water can be improved.

[0013] In the water-soluble film, it is preferable that the sum of the contents of the sorbitol and the polymer formed from polyethylene glycol and / or polyglycerol is 18 to 30 parts by mass, with respect to 100 parts by mass of the anion group-modified polyvinyl alcohol resin, whereby the breakage of the powder detergent packaging capsule due to the embrittlement of the film caused by the transfer of the plasticizer to the powder detergent can be prevented.

[0014] In the water-soluble film, it is preferable that the plasticizer contains glycerol, and the content of the glycerol is 1 to 32 parts by mass, with respect to 100 parts by mass of the anion group-modified polyvinyl alcohol resin, whereby the moldability of the water-soluble film for a detergent packaging capsule can be further improved.

[0015] In the water-soluble film, it is preferable that the water-soluble film contains a sulfite, and the content of the sulfite is 0.1 to 1.9 parts by mass, with respect to 100 parts by mass of the anion group-modified polyvinyl alcohol resin, whereby the discoloration of the detergent packaging capsule caused by heating or the like during molding can be prevented.

[0016] In the water-soluble film, it is preferable that the sulfite is sodium sulfite.

[0017] The water-soluble film is such that, when a 22 mL liquid detergent is enclosed in a capsule formed of the water-soluble film for a detergent packaging capsule, which has a box shape with rounded corners, and which is vacuum-formed in a cavity having an opening area of 2000 mm 2 a depth of 15 mm, and which has a height maintenance rate of 86% or more after being stored for 7 days at 23°C, 50% RH, the liquid detergent including: a surfactant 72.9% by mass, including a polyoxyethylene alkyl ether, a linear alkylbenzene sulfonate, an alkyl ether sulfate ester salt, and a polyethylene glycol monolaurate; glycerin 5.1% by mass; polyethylene glycol (PEG 400) 14.5% by mass; and water 7.5% by mass.

[0018] The water-soluble film is such that, when 35 g of sodium carbonate is filled in a flat bag of 165 mm x 65 mm in size formed of the water-soluble film for a detergent packaging capsule, the tensile elastic modulus of the water-soluble film obtained by a tensile elastic modulus measurement test of the water-soluble film in contact with the powder detergent ingredient after being stored for 7 days in an environment of 50°C, 50% RH, is less than 220 MPa.

[0019] The detergent packaging capsule capable of achieving the object is characterized in that a liquid detergent and / or a powder detergent is enclosed in a capsule formed of the water-soluble film for a detergent packaging capsule.

[0020] Effects of the Invention

[0021] The water-soluble film for a detergent packaging capsule according to the present invention can prevent sorbitol from being precipitated onto the surface of the film during long-term storage, can maintain the moldability when a detergent packaging capsule is produced, and can prevent the bag of a detergent packaging capsule in which a powder detergent is enclosed from being broken, exhibit a brittleness suppression effect, and have excellent solubility after the powder detergent is packaged, and can not cause discoloration, particularly yellowing, after the powder detergent is packaged, and can maintain the tension feeling of the film forming the detergent packaging capsule even when a liquid detergent is enclosed in the detergent packaging capsule. DETAILED DESCRIPTION

[0022] The water-soluble film for a detergent packaging capsule (hereinafter referred to simply as a water-soluble film) of the present invention is mainly formed of an anionic group-modified polyvinyl alcohol resin. As the anionic group-modified polyvinyl alcohol resin, there is no particular limitation, and examples thereof include a maleic acid-modified polyvinyl alcohol resin, an itaconic acid-modified polyvinyl alcohol resin, an acrylic acid-modified polyvinyl alcohol resin, a methacrylic acid-modified polyvinyl alcohol resin, a 2-acrylamide-2-methylpropane sulfonic acid-modified polyvinyl alcohol resin, and the like.

[0023] The ratio (degree of modification) of the number of moles of the monomer or the like reacted for modification in the anion group-modified polyvinyl alcohol resin to the number of moles of the total monomers constituting the anion group-modified polyvinyl alcohol resin is preferably 0.5 to 6.0 mol%, more preferably 0.5 to 4.0 mol%, and further preferably 0.5 to 2.0 mol%. In the case where the degree of modification of the anion group-modified polyvinyl alcohol resin is less than 0.5 mol%, there is a tendency that the solubility in water decreases, and in the case where it exceeds 6.0 mol%, there is a tendency that the productivity of the anion group-modified polyvinyl alcohol resin decreases.

[0024] In particular, as the anion group-modified polyvinyl alcohol resin, it is preferable that the modification type is maleic acid modification and the degree of modification is 0.5 to 2.0 mol%, so that the solubility in water of the detergent packaging capsule can be improved.

[0025] The anion group-modified polyvinyl alcohol resin can be obtained by saponifying a polymer obtained by polymerization by a publicly known method such as a solution polymerization method, a bulk polymerization method, a suspension polymerization method, or the like. The saponification is performed using a base or an acid, and the use of a base is particularly preferable. The degree of saponification (average degree of saponification) is not particularly limited, but since it is easy to adjust the solubility in water when it is in the range of 86 to 100 mol%, it is preferably 86 to 100 mol%, more preferably 87 to 99 mol%, and further preferably 88 to 94 mol%. In the case where the degree of saponification is less than 86 mol%, there is a tendency that the water-solubility of the anion group-modified polyvinyl alcohol resin decreases. Note that the degree of saponification is measured in accordance with JIS K6726 (1994).

[0026] In the anion group-modified polyvinyl alcohol resin used in the present application, repeating units composed of the following monomers can be contained without impairing the effects of the present application. As the monomers, for example, the following can be mentioned: olefins such as ethylene, propylene, isobutylene, α-octylene, α-dodecene, α-octadecene, and the like; completely alkyl esters of unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, maleic anhydride, itaconic acid, and the like; nitriles such as acrylonitrile, methacrylonitrile, and the like; amides such as acrylamide, methacrylamide, and the like; alkyl vinyl ethers; N-acrylamidomethyl trimethylammonium chloride; allyl trimethylammonium chloride; dimethyldiallyl ammonium chloride; dimethylallyl vinyl ketone; N-vinylpyrrolidone; chlorinated ethylene; vinylidene chloride; polyoxyalkylene (meth) allyl ethers such as polyoxyethylene (meth) allyl ether, polyoxypropylene (meth) allyl ether, and the like; polyoxyalkylene (meth) acrylates such as polyoxyethylene (meth) acrylate, polyoxypropylene (meth) acrylate, and the like; polyoxyalkylene (meth) acrylamides such as polyoxyethylene (meth) acrylamide, polyoxypropylene (meth) acrylamide, and the like; polyoxyethylene (1- (meth) acrylamido-1, 1-dimethylpropyl) ester; polyoxyethylene vinyl ether; polyoxypropylene vinyl ether; polyoxyethylene allylamine; polyoxypropylene allylamine; polyoxyethylene vinylamine; polyoxypropylene vinylamine; and the like.

[0027] Further, the following can also be mentioned: cationic group-containing monomers such as N-acrylamidomethyl trimethylammonium chloride, N-acrylamidoethyl trimethylammonium chloride, N-acrylamidopropyl trimethylammonium chloride, 2-acryloyloxyethyl trimethylammonium chloride, 2-methacryloyloxyethyl trimethylammonium chloride, 2-hydroxy-3-methacryloyloxypropyl trimethylammonium chloride, allyl trimethylammonium chloride, methallyl trimethylammonium chloride, 3-butenyl trimethylammonium chloride, dimethyldiallyl ammonium chloride, diethyldiallyl ammonium chloride, and the like.

[0028] The anion group-modified polyvinyl alcohol resin preferably has a polymerization degree of 700 or more, more preferably 900 or more, and further preferably 1200 or more. In the case where the polymerization degree is less than 700, the mechanical properties of the water-soluble film and the pressure resistance of the finally obtained liquid detergent packaging capsule tend to decrease. The upper limit of the polymerization degree is preferably 2500, more preferably 900 or more and 2200 or less, and further preferably 1200 or more and 1700 or less. In the case where the polymerization degree exceeds 2500, the water-solubility of the water-soluble film tends to decrease.

[0029] The 4% by mass aqueous solution viscosity of the anion group-modified polyvinyl alcohol resin at 20°C is not particularly limited, and is preferably 7.0 to 55 mPa-s, more preferably 9.0 to 50 mPa-s, and further preferably 12 to 35 mPa-s. The 4% by mass aqueous solution viscosity is measured in accordance with JIS K6726 (1994).

[0030] The content of the above-described anion group-modified polyvinyl alcohol resin in 100 parts by mass of the water-soluble film of the present application is preferably 69 to 97 parts by mass, and particularly further preferably 60 to 80 parts by mass, so that the moisture content in the water-soluble film can be easily adjusted to an appropriate range. In the case where the content is less than 60 parts by mass, the tensile strength of the water-soluble film can be insufficient, and in the case where the content exceeds 80 parts by mass, the flexibility of the water-soluble film can be insufficient.

[0031] A plurality of anion group-modified polyvinyl alcohol resins can also be used in the water-soluble film of the present application. In this case, at least one of the anion group-modified polyvinyl alcohol resins can be different in terms of molecular weight, degree of polymerization, 4% by mass aqueous solution viscosity, degree of saponification, degree of modification, type of modification, and the like. Note that, within a range that does not impair the object of the present application, other modified polyvinyl alcohol resins and / or unmodified polyvinyl alcohol can also be contained as needed.

[0032] The water-soluble film of the present application incorporates sorbitol and a polymer formed from polyethylene glycol and / or polyglycerol as a plasticizer. Sorbitol is a sugar alcohol having a melting point of 80°C or higher. In general, even an anion group-modified polyvinyl alcohol resin that is a water-soluble resin used for forming a capsule is incorporated with a plasticizer in order to ensure ease of molding, and when a powder detergent is enclosed in a capsule formed from a water-soluble film containing a plasticizer, the plasticizer in the water-soluble film sometimes transfers to the powder detergent side, resulting in embrittlement of the water-soluble film and bag breakage.

[0033] In this regard, a capsule formed from a water-soluble film containing sorbitol as a plasticizer can suppress the transfer of sorbitol to the powder detergent side, and can prevent embrittlement of the water-soluble film due to the transfer of the plasticizer. However, a water-soluble film containing a large amount of sorbitol in order to ensure moldability can sometimes cause sorbitol to precipitate onto the surface of the water-soluble film over time during storage, impairing the transparency of the water-soluble film.

[0034] To prevent such sorbitol precipitation during storage and maintain moldability, the content of sorbitol is preferably 6 to 15 parts by mass, more preferably 7 to 13 parts by mass, and further preferably 8 to 11 parts by mass, relative to 100 parts by mass of the anion group-modified polyvinyl alcohol resin. For a water-soluble film having a content of sorbitol of less than 6 parts by mass, moldability is reduced, and for a water-soluble film having a content of sorbitol of more than 15 parts by mass, sorbitol precipitates during storage, resulting in reduced transparency.

[0035] In the water-soluble film of the present application, in addition to the sorbitol as a plasticizer, a polymer formed from polyethylene glycol and / or polyglycerol is contained.

[0036] As the polyethylene glycol, the weight average molecular weight (hereinafter referred to as average molecular weight) is preferably 106 or more, further preferably 150 to 400, and particularly preferably 200. A polyethylene glycol having an average molecular weight of less than 106 tends to easily volatilize from the water-soluble film, and a polyethylene glycol having an average molecular weight of more than 400 tends to have reduced compatibility with the anion group-modified polyvinyl alcohol resin. In addition, as the polyglycerol, the molecular weight is preferably 166 to 750, further preferably 166 to 500, and particularly preferably 166, which is diglycerol. A polyglycerol having a molecular weight of more than 750 tends to have reduced compatibility with the anion group-modified polyvinyl alcohol resin.

[0037] Such a polymer can contribute to improved moldability of the water-soluble film, and is difficult to transfer to the powder detergent enclosed in the capsule formed from the water-soluble film due to steric hindrance. However, for a water-soluble film containing a large amount of the polymer, the capsule enclosing the powder detergent sometimes yellows. It is presumed that this phenomenon is caused by the polymer in the water-soluble film capturing oxygen in the capsule enclosing the powder detergent, promoting oxidation of the components in the water-soluble film. Therefore, to prevent yellowing of the water-soluble film of the capsule enclosing the powder detergent while improving the moldability of the water-soluble film, the content of the polyethylene glycol and / or polyglycerol, i.e., the polymer, needs to be 3 to 15 parts by mass, preferably 5 to 15 parts by mass, and more preferably 8 to 15 parts by mass, relative to 100 parts by mass of the anion group-modified polyvinyl alcohol resin. In the case where the content of the polymer is less than 3 parts by mass, it is difficult to improve the moldability of the water-soluble film, and in the case where the content exceeds 15 parts by mass, the water-soluble film of the capsule enclosing the powder detergent easily yellows.

[0038] In addition, the total of sorbitol and the polymer formed from polyethylene glycol and / or polyglycerol is 18 to 30 parts by mass, more preferably 18 to 28 parts by mass, and further preferably 18 to 25 parts by mass, relative to 100 parts by mass of the anion group-modified polyvinyl alcohol resin, thereby being able to prevent bag breakage caused by embrittlement of the water-soluble film due to transfer of the plasticizer to the powder detergent.

[0039] As the polymer, either of polyethylene glycol and polyglycerin can be used alone, or polyethylene glycol can be used in combination with polyglycerin.

[0040] Further, from the viewpoint of softness and the like of the resulting packaging capsule, glycerin as a plasticizer can be contained in the water-soluble film. The content of glycerin is 1 to 32 parts by mass, more preferably 5 to 25 parts by mass, and further preferably 5 to 20 parts by mass, relative to 100 parts by mass of the anion group-modified polyvinyl alcohol resin, whereby the moldability of the water-soluble film and the softness of the packaging capsule can be further improved.

[0041] In the water-soluble film of the present application, in addition to the above-mentioned plasticizer, a compound obtained by adding ethylene oxide to a generally used plasticizer such as a polyhydric alcohol such as trimethylolpropane, dipropylene glycol, propylene glycol, 2-methyl-l,3-propanediol, and the like; a polyether such as polypropylene glycol, and the like; a phenol derivative such as bisphenol A, bisphenol S, and the like; an amide compound such as N-methylpyrrolidone, and the like; a polyhydric alcohol such as pentaerythritol, sorbitol, and the like can be contained within a range not impairing the object of the present application.

[0042] When a liquid detergent is enclosed in a capsule formed of a water-soluble film containing a prescribed amount of such a plasticizer, the tension feeling of the water-soluble film forming the capsule is sometimes lost. It is presumed that this phenomenon is caused by the fact that the plasticizer is also contained in the liquid detergent, and the plasticizer in the water-soluble film moves in a balanced manner with the plasticizer in the liquid detergent. Therefore, in order to maintain the tension feeling of the water-soluble film forming a capsule enclosing a liquid detergent, it is important to set the total content of the plasticizer consisting of sorbitol, polyethylene glycol and / or polyglycerin, glycerin, and a generally used plasticizer to 25 parts by mass or more, relative to 100 parts by mass of the anion group-modified polyvinyl alcohol resin. In the case where the content of the plasticizer is less than 25 parts by mass, the water-soluble film forming a capsule enclosing a liquid detergent easily loses the tension feeling. The upper limit of the total content of the plasticizer is 50 parts by mass, relative to 100 parts by mass of the anion group-modified polyvinyl alcohol resin. In the case where the total content of the plasticizer exceeds 50 parts by mass, the tensile strength of the water-soluble film easily decreases, and the plasticizer easily precipitates onto the surface of the water-soluble film. The preferable total content of the plasticizer is 25 to 50 parts by mass, more preferably 25 to 40 parts by mass, and further preferably 28 to 35 parts by mass, relative to 100 parts by mass of the anion group-modified polyvinyl alcohol resin.

[0043] The anion group-modified polyvinyl alcohol resin used in the present application is yellowed by heating at the time of film formation, at the time of forming a water-soluble film, and the like, and even if a water-soluble film is formed and a capsule is sealed with a liquid detergent and / or a powder detergent, the capsule sometimes becomes colored due to deterioration over time during storage. In order to prevent such yellowing and deterioration, it is preferable to contain a sulfite salt as an antioxidant. As the sulfite salt, for example, sodium sulfite, sodium bisulfite, sodium metabisulfite, potassium sulfite, potassium metabisulfite, calcium sulfite, and ammonium sulfite can be mentioned. Sodium sulfite is particularly preferable. These sulfite salts can be used alone or in combination. Furthermore, the sulfite salt contained in the water-soluble film for a detergent packaging capsule can be the same as or different from the sulfite salt contained in the sealed detergent. However, in a water-soluble film containing a large amount of a sulfite salt, the sulfite salt sometimes precipitates during storage. Therefore, it is preferable to set the content of the sulfite salt to 0.1 to 1.9 parts by mass, more preferably 0.1 to 1.5 parts by mass, and further preferably 0.1 to 1.1 parts by mass, with respect to 100 parts by mass of the anion group-modified polyvinyl alcohol resin. By the content of the sulfite salt within this range, yellowing due to heating at the time of film formation and at the time of forming can be prevented, coloring of a capsule in which a detergent is sealed can be prevented, and precipitation of the sulfite salt from a formed water-soluble film during storage can also be prevented.

[0044] In the water-soluble film of the present application, other additives can be incorporated without impairing the properties thereof. As the other additives, a surfactant, a water-soluble polymer, and an additive can be contained.

[0045] As the surfactant, for example, nonionic surfactants, anionic surfactants, cationic surfactants, and zwitterionic surfactants can be mentioned. Among these, the surfactant is preferably sodium polyoxyethylene lauryl ether acetate, potassium polyoxyethylene alkyl ether phosphate ester, sodium di-2-ethylhexyl sulfosuccinate, and sodium polyoxyethylene alkyl ether sulfate. These can be used alone or in combination. The content of the surfactant is preferably 0.1 to 2.0 parts by mass with respect to 100 parts by mass of the anion group-modified polyvinyl alcohol resin. The surfactant can impart release properties from a casting surface at the time of manufacturing a water-soluble film, or facilitate processing such as sealing (water lamination, heat sealing) at the time of manufacturing a liquid detergent packaging capsule, a powder detergent packaging capsule, or a packaging capsule containing a powder detergent and a liquid detergent.

[0046] Further, as the water-soluble polymer, for example, sodium polyacrylate, polyethylene oxide, polyvinylpyrrolidone, dextrin, chitosan, chitin, methylcellulose, hydroxyethylcellulose, and the like can be exemplified. As the additive, for example, various fillers such as silicon dioxide, aluminosilicate (zeolite), titanium oxide, talc, starch, crosslinked acrylic acid microparticles, coloring agents, flavoring agents, extenders, antifoaming agents, release agents, ultraviolet absorbers, rust-preventive agents, liquid paraffin, fluorescent brightening agents, chelating agents, bittering agents such as denatonium benzoate, fatty acid-based substances, inorganic powders, and the like can be exemplified.

[0047] The film production method of the water-soluble film of the present application has a step of preparing an aqueous solution and a film production step of producing a water-soluble film.

[0048] The step of preparing an aqueous solution is not particularly limited in the method of preparing an aqueous solution, and for example, a method of dissolving an anion group-modified polyvinyl alcohol resin, a plasticizer, a surfactant, an additive such as a filler, and the like in a dissolving tank or the like; and a method of kneading an anion group-modified polyvinyl alcohol resin, a plasticizer, a surfactant, an additive such as a filler, and the like in a water-containing state together using a twin-screw extruder, and the like can be exemplified.

[0049] The film production step is not particularly limited in the method of producing a water-soluble film containing an anion group-modified polyvinyl alcohol resin, and for example, a method of supplying an aqueous solution or an aqueous solvent solution of a composition containing an anion group-modified polyvinyl alcohol resin to a surface (including a metal belt surface) of a metal roll or the like that is a support member rotating using a publicly known device, peeling and winding from the surface (including the metal belt surface) of the metal roll or the like while drying can be adopted. Note that, as the method of supplying, a publicly known means such as a solution casting method (casting method), a roll coating method, and the like can be adopted.

[0050] Further, in order to emboss the water-soluble film as needed (for example, Matte embossing), heating and pressing are performed between a pair of biaxial rolls having an embossing concave-convex shape on the surface, while an embossing pattern is imparted.

[0051] The moisture content of the water-soluble film of the present application obtained by film production is preferably 4.0 to 9.0 mass%, more preferably 4.5 to 8.0 mass%, and further preferably 5.0 to 7.5 mass% in a normal temperature, normal pressure, and normal humidity environment. In the case where the moisture content is less than 4.0 mass%, there is a tendency that the softness of the water-soluble film decreases, and in the case where the moisture content exceeds 9.0 mass%, there is a tendency that the water-soluble films easily adhere to each other.

[0052] The thickness of the water-soluble film of the present invention after film formation is preferably 40 to 120 μm, more preferably 50 to 110 μm, and even more preferably 60 to 90 μm. Water-soluble films with a thickness of less than 40 μm tend to have insufficient tensile strength for use in detergent packaging capsules, while water-soluble films with a thickness exceeding 120 μm tend to have reduced moldability when molded into detergent packaging capsules.

[0053] Furthermore, when the haze of the obtained water-soluble film measured in accordance with JIS K7136 (2000) is 50% or less, the transparency is better. A water-soluble film having a haze exceeding 50% tends to have insufficient transparency.

[0054] The water-soluble film of the present invention may consist of a single layer or may be formed by laminating two or more layers of the same or different water-soluble films having the composition of the water-soluble film of the present invention. Detergent packaging capsules using such a water-soluble film of the present invention are formed by laminating at least two end edges of the water-soluble film of the present invention, and contain detergent. Furthermore, the detergent packaging capsules are manufactured by filling and sealing the contents using heat sealing or water sealing. The detergent packaging capsules are preferably formed by thermoforming or vertical form-fill-seal (VFFS) methods, and more preferably by thermoforming.

[0055] Detergent capsules produced by thermoforming can be manufactured, for example, by following the following method: a water-soluble film is formed along the inner wall of a cavity of a predetermined capacity formed in a mold. After forming a depression with a predetermined capacity, the bottom portion of the depression is formed with the water-soluble film. A predetermined amount of detergent is then filled into the depression. Subsequently, a predetermined amount of water is applied to one side of the top portion of the water-soluble film. The predetermined surface of the bottom portion of the water-soluble film, located at the periphery of the mold cavity, is press-bonded to the water-coated surface of the top portion. Furthermore, the depth of the detergent capsule can be adjusted as appropriate within a range that allows for deep drawing.

[0056] Furthermore, detergent packaging capsules produced by the VFFS method can be produced by folding a water-soluble film vertically, heat-sealing the overlapped ends vertically and horizontally, filling the folded water-soluble film with detergent, and sealing the top.

[0057] The detergent packaging capsule of the present invention can enclose powder detergents as well as liquid detergents and / or gel detergents. Furthermore, the capsule can be used to enclose a single detergent, either a powder detergent or a liquid detergent, or to form a single-package multi-chamber detergent packaging capsule in which two or more detergents, such as a powder detergent and a liquid detergent, are separately enclosed.

[0058] Example

[0059] Hereinafter, the embodiments of the present application will be described in detail, but the scope of the present application is not limited to these embodiments.

[0060] (anion group-modified polyvinyl alcohol resin (modified PVA resin))

[0061] As the modified PVA resin, at least two of the following plasticizers are added to a maleic acid-modified polyvinyl alcohol resin having a modification degree, a polymerization degree, an average saponification degree, and a 4 mass% aqueous solution viscosity at 20°C (hereinafter referred to as a 4 mass% viscosity) as shown in Table 1 below.

[0062] [Table 1]

[0063] A-1 Modification degree (mole %) 1.9 Polymerization degree 1700 Average saponification degree (mole %) 88 4 mass % viscosity (mPa-s) 28

[0064] (plasticizers and other additives)

[0065] Plasticizer

[0066] B-1: Sorbitol

[0067] B-2: Diglycerol

[0068] B-3: Polyethylene glycol (PEG 200)

[0069] B-4: Glycerol

[0070] Other additives

[0071] Antioxidant

[0072] C-1: Sodium sulfite

[0073] Surfactant

[0074] D-1: Potassium salt of polyoxyethylene alkyl ether phosphate ester

[0075] Example 1

[0076] (Preparation of water-soluble film composition)

[0077] Using 100 parts by mass of A-1 of the modified PVA resin shown in Table 1, the above plasticizers, antioxidant, and surfactant were added as shown in Table 2, and kneading was performed in a water-containing state using a twin-screw extruder, and preparation was performed in such a manner that the concentration of the water-soluble film composition became 55 to 59 mass%.

[0078] (Film formation)

[0079] The water-soluble film-forming composition having the composition shown in Table 2 was cast from a T-die at 90°C onto the surface of a metal roll (first drying roll) whose surface temperature was maintained at 86°C. The water-soluble film-forming composition was dried for 80 seconds while rotating the metal roll (first drying roll), peeled from the first drying roll, and further dried with a second drying roll and the roll(s) thereafter in such a manner that one side of the PVA film was in contact with the other side on each drying roll to produce a water-soluble film having a thickness of 90 μm.

[0080] Examples 2 to 5 and Comparative Examples 1 to 3

[0081] In Examples 2 to 5 and Comparative Examples 1 to 3, a water-soluble film-forming composition was prepared in the same manner as in Example 1 except that the composition of the water-soluble film-forming composition was changed to the composition shown in Table 2, and a water-soluble film having a thickness of 90 μm was produced in the same manner as in Example 1.

[0082] (Extraction evaluation test)

[0083] One sheet of the water-soluble film obtained in Examples 1 to 5 and Comparative Examples 1 to 3 was cut into a size of 100 mm x 100 mm and stored in an environment of 23°C, 33% RH for two months. Thereafter, the water-soluble film was visually observed. No white extract was observed as pass (O), and white extract was observed as fail (X). The results are shown in Table 2.

[0084] (Tension of liquid detergent packaging capsule evaluation test)

[0085] [Preparation of liquid detergent]

[0086] A liquid detergent was prepared by mixing 21.2 mass% of TOP SUPER NANOX (manufactured by LION Corporation: trade name), 73.7 mass% of EMANON 1112 (manufactured by Kao Corporation: trade name), and 5.1 mass% of glycerin, the liquid detergent containing 72.9 mass% of surfactant including polyoxyethylene alkyl ether, linear alkylbenzene sulfonate, alkyl ether sulfate, polyethylene glycol monolaurate; 5.1 mass% of glycerin; 14.5 mass% of polyethylene glycol (PEG 400); and 7.5 mass% of water.

[0087] [Preparation of liquid detergent packaging capsule]

[0088] One sheet of the water-soluble film obtained in each of the examples and comparative examples was used as a water-soluble film for the bottom, and was installed in a state of being spread without wrinkles or slack in a cavity (opening portion area 2000 mm 2, a box-shaped cavity with a depth of 15 mm and rounded corners) on a mold. The water-soluble film is heated at about 90°C for 5 seconds, and vacuum formed so that the water-soluble film follows the cavity and is formed into a concave water-soluble film sheet. About 22 mL of the prepared liquid detergent is filled into the concave water-soluble film sheet on the cavity. Then, the water-soluble film obtained in the same way is used as the top water-soluble film, and Labotowel (manufactured by UNICHEMY Co., Ltd.; trade name) moistened with water is used with a water coating amount of 44 to 54 g / m 2 Water is applied to the top water-soluble film. Using a 1.5 kg metal roller, the water-coated top water-soluble film is immediately pressed together with the water-soluble film sheet at the edge of the recess that will become the bottom side under vacuum. After holding for approximately 1 minute and 30 seconds, vacuuming is stopped, and the capsule array is removed from the cavity and cut into pieces to produce liquid detergent packaging capsules.

[0089] [Determination of capsule height maintenance rate]

[0090] After removing the liquid detergent capsule from the cavity, let it stand at room temperature for approximately 7 minutes. At this point, use a height gauge (Mitutoyo Co., Ltd.: Absolute Digimatic Heightgage) to measure the initial height (h0) of the liquid detergent capsule. The liquid detergent capsule was further stored at 23°C and 50% RH for 7 days. At this point, the height (h1) of the liquid detergent capsule after storage was also measured using the same height gauge. The capsule height maintenance rate (%) was calculated as an evaluation indicator of the tension of the liquid detergent capsule using the following formula.

[0091] Capsule height maintenance rate (%) = h1 / h0×100

[0092] A capsule height retention rate of 86% or greater was rated "0," and a value of "x" was rated "less than 86." A value of "0" indicates a capsule with good tension and a consumer-pleasing appearance. The results are summarized in Table 2.

[0093] (Tensile elastic modulus of water-soluble film in contact with powdered detergent)

[0094] [Production of a water-soluble film that contacts powdered detergent ingredients]

[0095] A water-soluble film obtained in Examples 1 to 5 and Comparative Examples 1 to 3 was cut into a size of 330 mm x 65 mm, and the long side was folded with the air face at the time of casting as the inner side, and both ends and both sides were heat-sealed using SHOP SEALER FS-315 (manufactured by Fuji Impulse Co., Ltd.: trade name) to produce a flat bag of 165 mm x 65 mm. Sodium carbonate as a powder detergent ingredient was filled into the flat bag, and the remaining one side was heat-sealed, five holes were made in the upper surface of the flat bag, and the flat bag was stored for 7 days in an environment of 50°C and 50% RH. After that, the flat bag was cut open, and the sodium carbonate was taken out, and the sodium carbonate adhering to the film was wiped off. At this time, the portion of the flat bag corresponding to the bottom surface when the sodium carbonate was stored was used as the water-soluble film in contact with the powder detergent ingredient.

[0096] [Production of water-soluble film in contact with powder detergent ingredient]

[0097] A water-soluble film obtained in Examples 1 to 5 and Comparative Examples 1 to 3 was cut into a size of 330 mm x 75 mm, and the long side was folded with the air face at the time of casting as the inner side, and both ends and both sides were heat-sealed using SHOP SEALER FS-315 (manufactured by Fuji Impulse Co., Ltd.: trade name) to produce a flat bag of 165 mm x 75 mm. A dishwasher-specific powder detergent (manufactured by Reckitt Benckiser Co., Ltd.: Finish) was filled into the flat bag, and the remaining one side was heat-sealed, five holes were made in the upper surface of the flat bag, and the flat bag was stored for 7 days in an environment of 50°C and 50% RH. After that, the flat bag was cut open, and the powder detergent was taken out, and the detergent adhering to the film was wiped off. At this time, the portion of the flat bag corresponding to the bottom surface when the powder detergent was stored was used as the water-soluble film in contact with the powder detergent.

[0098] [Measurement test of tensile elastic modulus of water-soluble film in contact with powder detergent ingredient and water-soluble film in contact with powder detergent]

[0099] The water-soluble film in contact with the powder detergent ingredient and the water-soluble film in contact with the powder detergent were stored for 1 day in an environment of 23°C and 33% RH, and a tensile test was measured using a tensile tester AGS-1 kN (manufactured by Shimadzu Corporation: trade name) based on JIS K7127 (1999). The measurement conditions were as follows.

[0100] Measurement environment: 23°C, 50% RH.

[0101] Film test piece: width 15 mm x length 150 mm.

[0102] Distance between grips: 100 mm.

[0103] Tensile test speed: 300 mm / minute.

[0104] The tensile elastic modulus at this time is 0 when it is less than 220 MPa, and is X when it is 220 MPa or more. 0 indicates that the film is soft, and the embrittlement of the water-soluble film caused by the packaging of the powder detergent is inhibited. The results are summarized in Table 2.

[0105] [Table 2]

[0106]

[0107] As is apparent from Table 2, as shown in Examples 1 to 5, the content of sorbitol is 10 parts by mass, the content of the polymer formed from PEG 200 and / or diglycerol as polyethylene glycol is 8 to 15 parts by mass, and the content of the total plasticizer including sorbitol and PEG 200 and / or diglycerol is 33 parts by mass, with respect to 100 parts by mass of the modified PVA resin. At this time, in the elution evaluation test of the obtained water-soluble film, even if long-term storage, the sorbitol is prevented from eluting to the surface of the water-soluble film to reduce the transparency.

[0108] Further, as is apparent from Table 2, as an evaluation index of the tension feeling of the liquid detergent packaging capsule, as shown in Examples 1 to 5, the capsule height maintenance rate (%) is represented as a high value of 90% or more, and thus, even the liquid detergent packaging capsule into which the liquid detergent is enclosed, the excellent tension feeling can be maintained.

[0109] Furthermore, as is apparent from Table 2, as shown in Examples 1 to 5, the tensile elastic modulus of the water-soluble film contacting the powder detergent ingredient and the water-soluble film contacting the powder detergent is less than 220 MPa, and thus, the bag breakage caused by the embrittlement of the water-soluble film due to the migration of the plasticizer to the powder detergent of the powder detergent packaging capsule can be prevented.

[0110] Industrial applicability

[0111] The water-soluble film for the detergent packaging capsule of the present application can be used for the detergent packaging capsule into which the liquid detergent and / or the powder detergent is enclosed, and can be stored for a long time, and can contribute to the production schedule and the like of the long-term detergent packaging capsule.

Claims

1. A water-soluble film for detergent packaging capsules, characterized in that: The water-soluble film is a film formed by modifying polyvinyl alcohol resin containing anionic groups. The water-soluble film contains a plasticizer, and the plasticizer comprises sorbitol and a polymer formed by polyethylene glycol and / or polyglycerol. With respect to 100 parts by mass of the anionic group-modified polyvinyl alcohol resin, the content of the sorbitol is 6 to 15 parts by mass, the content of the polymer is 3 to 15 parts by mass, and the content of the plasticizer is 25 to 50 parts by mass.

2. The water-soluble film for detergent packaging capsules according to claim 1, characterized in that: The modification type of the anionic group-modified polyvinyl alcohol resin is maleic acid modification, and the modification degree is 0.5 to 6.0 mol %.

3. The water-soluble film for detergent packaging capsules according to claim 1, characterized in that: The total content of the sorbitol and the polymer formed of polyethylene glycol and / or polyglycerol is 18 to 30 parts by mass based on 100 parts by mass of the anionic group-modified polyvinyl alcohol resin.

4. The water-soluble film for detergent packaging capsules according to claim 1, characterized in that The plasticizer contains glycerin, and the content of the glycerin is 1 to 32 parts by mass based on 100 parts by mass of the anionic group-modified polyvinyl alcohol resin.

5. The water-soluble film for detergent packaging capsules according to claim 1, characterized in that The water-soluble film contains sulfite, and the content of the sulfite is 0.1 to 1.9 parts by mass based on 100 parts by mass of the anionic group-modified polyvinyl alcohol resin.

6. The water-soluble film for detergent packaging capsules according to claim 5, characterized in that: The sulfite is sodium sulfite.

7. The water-soluble film for detergent packaging capsules according to claim 1, characterized in that The water-soluble film for the detergent packaging capsule has an opening area of ​​2000 mm. 2 When 22 mL of liquid detergent was enclosed in a vacuum-molded capsule with a 15 mm deep, rounded box-shaped cavity and stored at 23°C and 50% RH for 7 days, the height maintenance rate was over 86%. The liquid detergent comprises: 72.9% by mass of a surfactant, wherein the surfactant comprises polyoxyethylene alkyl ether, linear alkylbenzene sulfonate, alkyl ether sulfate, and polyethylene glycol monolaurate; Glycerol 5.1% by mass; Polyethylene glycol PEG400 14.5 mass%; as well as Water 7.5 mass%.

8. The water-soluble film for detergent packaging capsules according to claim 1, characterized in that When a flat bag of 165 mm × 65 mm in size formed from the water-soluble film for detergent packaging capsules is filled with 35 g of sodium carbonate, and the water-soluble film in contact with the powdered detergent component is exposed and stored for 7 days at 50° C. and 50% RH, the elastic modulus of the water-soluble film obtained in a tensile elastic modulus measurement test is less than 220 MPa.

9. A detergent packaging capsule, characterized in that: Liquid detergent and / or powder detergent is enclosed in a capsule formed of the water-soluble film for detergent packaging capsules according to claim 1.

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