Water-soluble film, drug package using same, and method for producing same

Abstract

Provided is a gelatin-containing water-soluble film which has excellent water solubility and excellent sealing properties and / or mechanical properties such as film strength and / or elongation. The water-soluble film contains gelatin and a polyvinyl alcohol resin (A), and the polyvinyl alcohol resin (A) contains a modified polyvinyl alcohol resin.

Description

Technical Field

[0001] The present invention relates to a water-soluble film containing gelatin, which is a natural raw material. More specifically, it relates to a water-soluble film containing gelatin and a polyvinyl alcohol-based resin, and a pharmaceutical packaging body using the same. Background Art

[0002] Water-soluble films using gelatin, a naturally derived raw material, have long been known as packaging materials for foods and the like. For example, the following are known: An edible film formed by mixing pectin, glycerin, and sucrose fatty acid esters with gelatin as a base and molding them into a film exhibits excellent solubility, heat-sealability, and blocking resistance (see Patent Document 1); and a packaging film constructed by adding a small amount of collagen to gelatin to prevent moisture absorption by the contents during storage and the release of other components such as flavor and / or aroma, which dissolves in hot water during use (see Patent Document 2).

[0003] In addition, there have been proposed: an edible film having improved moisture permeability resistance and heat sealing properties by forming a hydrophobic layer such as food wax on one side of an edible base film formed by mixing agar and gelatin (see Patent Document 3); and an edible film having excellent thermal solubility, heat sealing properties, and processability, comprising a paste containing at least inulin and other pastes containing agar, carrageenan, gelatin, furcellaran, pectin, etc. (see Patent Document 4).

[0004] Furthermore, in recent years, from the perspective of protecting the global environment, there has been a desire to develop highly biodegradable films using raw materials of natural origin to replace conventional plastic films containing raw materials of petroleum origin. From the perspectives of safety and price, gelatin, which has protein as its main component, has attracted attention as a substitute for raw materials of petroleum origin and / or as a raw material for films for packaging purposes.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 6-105660

[0008] Patent Document 2: Japanese Patent Application Laid-Open No. 6-183456

[0009] Patent Document 3: Japanese Patent Application Laid-Open No. 2002-95426

[0010] Patent Document 4: Japanese Patent Application Laid-Open No. 2008-79525 Summary of the Invention

[0011] Problems to be solved by the invention

[0012] However, the aforementioned conventional gelatin-containing films have insufficient mechanical properties such as strength and / or elongation. Further improvements are required to produce tougher films with excellent formability, particularly for use in individual packaging of food and / or medicines.

[0013] Furthermore, regarding sealing properties, particularly in the case of packaging liquids, if the strength of the sealing portion is low, there is a concern of liquid leakage, and further improvements are required.

[0014] Therefore, in this context, the present invention provides a water-soluble film containing gelatin and having excellent water solubility, mechanical properties such as film strength and / or elongation, and / or excellent sealing properties, a pharmaceutical packaging body using the same, and their production methods.

[0015] Solutions for solving problems

[0016] However, in view of the above situation, the present inventors conducted intensive research and found that by using a modified polyvinyl alcohol-based resin as a material used in combination with gelatin, a water-soluble film having excellent compatibility with gelatin, water solubility, mechanical properties, and sealing properties can be obtained.

[0017] Polyvinyl alcohol-based resins are biodegradable resins and can therefore solve the above-mentioned problems without significantly reducing the biodegradability of the entire water-soluble film. In addition, the proportion of petroleum-derived raw materials can be reduced compared to conventional water-soluble films containing polyvinyl alcohol-based resins.

[0018] The present invention includes the following aspects. [1]

[0020] A water-soluble film comprises gelatin and a polyvinyl alcohol-based resin (A), wherein the polyvinyl alcohol-based resin (A) comprises a modified polyvinyl alcohol-based resin. [2]

[0022] The water-soluble film according to [1], wherein the modified polyvinyl alcohol-based resin contains at least one modified polyvinyl alcohol-based resin selected from the group consisting of anionic group-modified polyvinyl alcohol, pyrrolidone ring group-modified polyvinyl alcohol, and amino group-modified polyvinyl alcohol. [3]

[0024] The water-soluble film according to [1] or [2], further comprising a plasticizer. [4]

[0026] The water-soluble film according to any one of [1] to [3], wherein the water content is 3 to 15% by mass. [5]

[0028] The water-soluble film according to any one of [1] to [4], which is used for drug packaging. [6]

[0030] The water-soluble film according to any one of [1] to [5], wherein the rate of increase in dissolution time of the film when the water-soluble film is allowed to stand in contact with a mixed solution of 11.2% by mass of propylene glycol, 13.4% by mass of glycerol, 8.4% by mass of ethanolamine, and 11.8% by mass of water at a pH of 9.5 for 3 weeks is less than 70%. [7]

[0032] The water-soluble film according to any one of [1] to [6], wherein the rate of increase in dissolution time of the film when the water-soluble film is allowed to stand in contact with a mixed solution of 6.2% by mass of propylene glycol, 10.9% by mass of glycerol, 7.6% by mass of ethanolamine, and 12.5% ​​by mass of water at a pH of 7.0 for 3 weeks is less than 70%. [8]

[0034] A medicine package comprising a package and a medicine contained in the package, wherein the package comprises the water-soluble film according to any one of [1] to [7]. [9]

[0036] The medicine package according to [8], wherein the medicine is a liquid detergent.

[10]

[0038] The drug package according to [9], wherein the pH value when the liquid detergent is dissolved or dispersed in water is 6 to 9.

[11]

[0040] A method for producing a water-soluble film, which is a method for producing a water-soluble film according to any one of [1] to [7], comprising: a casting step of preparing a film-forming raw material containing gelatin and a modified polyvinyl alcohol-based resin, and casting the film-forming raw material on a casting surface; and a drying step of drying the cast film-forming raw material.

[12]

[0042] A method for manufacturing a drug packaging body, which is a method for manufacturing a drug packaging body described in any one of [8] to

[10] , comprising: preparing a first water-soluble film, a second water-soluble film and a drug, placing the first water-soluble film and the second water-soluble film opposite to each other with the drug sandwiched therebetween, and partially abutting the first water-soluble film and the second water-soluble film; and pressing the abutting portions of the first water-soluble film and the second water-soluble film together.

[0043] Effects of the Invention

[0044] The water-soluble film of the present invention exhibits high compatibility between gelatin and modified polyvinyl alcohol-based resins, resulting in excellent water solubility (solubility), mechanical properties, and / or sealing properties. Furthermore, the film's solubility decreases over time when formed into packaging. Therefore, the film is suitable for packaging applications, particularly as an individual package for pharmaceuticals and / or foods. DETAILED DESCRIPTION

[0045] Hereinafter, the present invention will be described based on examples of modes for carrying out the present invention. However, the present invention is not limited to the embodiments described below.

[0046] In addition, when expressed as "X to Y" (X and Y are arbitrary numbers) in this specification, unless otherwise specified, it includes the meaning of "X or more and Y or less", and also includes the meaning of "preferably greater than X" or "preferably less than Y".

[0047] Furthermore, when expressed as "X or more" (X is an arbitrary number) or "Y or less" (Y is an arbitrary number), it also includes the meaning of "preferably greater than X" or "preferably less than Y".

[0048] Furthermore, “x and / or y (x, y are arbitrary structures)” means at least one of x and y, and has three meanings: only x, only y, and x and y.

[0049] Regarding the numerical ranges described in stages in this specification, the upper limit or lower limit of the numerical range in a certain stage can be arbitrarily combined with the upper limit or lower limit of the numerical range in other stages. In addition, in the numerical ranges described in this specification, the upper limit or lower limit of the numerical range can also be replaced with the value shown in the embodiments.

[0050] In this specification, "main component" refers to a component that has a significant influence on the properties of the object, and the content of this component is usually 50% by mass or more in the object, preferably 55% by mass or more, more preferably 60% by mass or more, further preferably 70% by mass or more, and can also be 100% by mass.

[0051] In the present invention, the "water-soluble film" refers to a film that dissolves in water at about room temperature (20°C).

[0052] In the present invention, dissolution of the thin film is determined as follows.

[0053] That is, the film was cut into a size of 3 cm × 5 cm, placed in a 1-liter beaker filled with water (1 liter), fixed with a jig, the water temperature was maintained at 20°C, and stirred with a stirrer (rotor length 3 cm, rotation speed 750 rpm). If no insoluble particles of the above-mentioned film with a diameter of more than 1 mm were observed, it was recorded as dissolved.

[0054] A water-soluble film according to an embodiment of the present invention (hereinafter sometimes referred to as "this water-soluble film") contains gelatin and a polyvinyl alcohol-based resin (A). In addition, a pharmaceutical package according to an embodiment of the present invention includes a package and a pharmaceutical agent enclosed in the package, and the package includes the above-mentioned water-soluble film. They will be described below.

[0055] It should be noted that in the present invention, polyvinyl alcohol is sometimes abbreviated as "PVA".

[0056] In addition, "film" also includes the meanings of "tape" and / or "sheet".

[0057] <Gelatin>

[0058] Gelatin is a substance obtained by extracting collagen, which is the main component of bones and skins of animals such as cows and / or pigs, and is mainly composed of a linear polymer (protein) of amino acids chemically. Usually, it is used as an additive for food in the form of a gelling agent and / or a thickening agent.

[0059] Usually, an aqueous gelatin solution gels below 25°C and dissolves above 30°C. Gelatin is classified into two types, acid treatment and alkali treatment, according to the manufacturing method, and each has a different isoelectric point. The isoelectric point of acid-treated gelatin is 6 to 9, which is a wide range. In contrast, the isoelectric point of alkali-treated gelatin shows a narrow range around 5. Usually, if it is used at a pH near the isoelectric point, it will cause a decrease in gel strength and / or turbidity of the gel.

[0060] In the water-soluble film of the present invention, alkali-treated gelatin is preferably used from the viewpoint of excellent physical properties.

[0061] <PVA-based resin (A)>

[0062] The PVA-based resin (A) can be used alone as one kind, or can contain two or more PVA-based resins with at least one difference in saponification degree, viscosity, modification type, and modification amount.

[0063] In the water-soluble film of the present invention, the PVA-based resin (A) contains a modified PVA-based resin as an essential component.

[0064] Among them, the modified PVA-based resin is preferably 50% by mass or more, more preferably 55% by mass or more, further preferably 60% by mass or more, particularly preferably 70% by mass or more, and can also be 100% in the PVA-based resin (A).

[0065] Specific examples of PVA-based resins (A) containing modified PVA-based resins include, for example, those containing one modified PVA-based resin, those containing two or more modified PVA-based resins, and those containing two or more types by combining modified PVA-based resins and unmodified PVAs. Among them, those containing only one modified PVA-based resin and those containing modified PVA-based resins and unmodified PVAs are preferred.

[0066] The mass content ratio of modified PVA resin to unmodified PVA is preferably 100 / 0 to 50 / 50, particularly preferably 100 / 0 to 55 / 45. From the perspective of film properties such as solubility in water and / or water sealing properties, it is preferably 99 / 1 to 55 / 45, particularly preferably 95 / 5 to 60 / 40, and further preferably 90 / 10 to 70 / 30.

[0067] The modified PVA resin used in the present water-soluble film preferably has at least one modifying group selected from anionic groups such as carboxyl groups, sulfonic acid groups, and phosphate groups, pyrrolidone ring groups, and amino groups, from the perspective of compatibility with gelatin and / or film solubility. Of these, anionic group-modified PVA resins are preferred. Examples of the anionic group include carboxyl groups, sulfonic acid groups, and phosphate groups. From the perspective of solubility stability over time, carboxyl groups and sulfonic acid groups are preferred, and carboxyl group-modified PVA resins are particularly preferred.

[0068] The average saponification degree of the PVA-based resin (A) is preferably 80 mol% or higher, particularly preferably 82 to 99.9 mol%, further preferably 85 to 98 mol%, and particularly preferably 90 to 96 mol%. If the average saponification degree is too low, the solubility of the film in water tends to decrease, or the solubility of the film tends to decrease over time due to the packaged drug. However, if the average saponification degree is too high, the solubility in water also tends to decrease.

[0069] When unmodified PVA is used as the PVA-based resin (A), the average saponification degree of the unmodified PVA is preferably 80 mol% or higher, particularly preferably 82 to 99 mol%, and even more preferably 85 to 90 mol%. If the average saponification degree is too low, the solubility of the water-soluble film in water tends to decrease. However, if the average saponification degree is too high, the solubility in water also tends to decrease.

[0070] In addition, the average saponification degree of the PVA-based resin (A) mentioned above means that the average saponification degree of the entire PVA-based resin contained in the present water-soluble film is within these ranges.

[0071] When a modified PVA resin is used as the PVA resin (A), the average saponification degree of the modified PVA resin is preferably 80 mol% or higher, particularly preferably 85 to 99.9 mol%, and even more preferably 90 to 99 mol%. If the average saponification degree is too low, the solubility of the water-soluble film in water tends to decrease over time depending on the pH of the packaged drug. It should be noted that if the average saponification degree is too high, the solubility of the water-soluble film in water tends to decrease significantly due to the thermal history during film formation.

[0072] When an anionic group-modified PVA resin is used as the modified PVA resin, the average saponification degree is preferably 85 to 99.9 mol %, particularly preferably 88 to 98 mol %, further preferably 90 to 97 mol %, and particularly preferably 90 to 95 mol %.

[0073] The viscosity of a 4% by mass aqueous solution of the PVA-based resin (A) at 20°C is preferably 5 to 60 mPa·s, particularly preferably 10 to 45 mPa·s, further preferably 15 to 40 mPa·s, and particularly preferably 21 to 35 mPa·s. If this viscosity is too low, the mechanical strength of the water-soluble film tends to decrease. If it is too high, the viscosity of the aqueous solution during film formation tends to increase, resulting in reduced productivity.

[0074] The 4 mass % aqueous solution viscosity at 20° C. of the PVA-based resin (A) means that the 4 mass % aqueous solution viscosity at 20° C. of the entire PVA-based resin contained in the water-soluble film is within these ranges.

[0075] When unmodified PVA is used as the PVA-based resin (A), the viscosity of a 4% by mass aqueous solution of the unmodified PVA at 20°C is preferably 10 to 60 mPa·s, particularly preferably 20 to 50 mPa·s, and even more preferably 30 to 45 mPa·s. If this viscosity is too low, the mechanical strength of the water-soluble film used as a packaging material tends to decrease. If it is too high, the viscosity of the aqueous solution during film formation tends to increase, resulting in reduced productivity.

[0076] When a modified PVA resin is used as the PVA resin (A), the viscosity of a 4% by mass aqueous solution of the modified PVA resin at 20°C is preferably 5 to 50 mPa·s, particularly preferably 10 to 40 mPa·s, and even more preferably 15 to 35 mPa·s. If the viscosity is too low, the mechanical strength of the water-soluble film used as a packaging material tends to decrease. If the viscosity is too high, the aqueous solution viscosity during film formation tends to increase, resulting in reduced productivity.

[0077] The modification amount of the PVA resin (A) is preferably 1 to 20 mol%, more preferably 1.5 to 15 mol%, and particularly preferably 2 to 12 mol%. If the modification amount is too low, the solubility of the water-soluble film in water tends to decrease. If it is too high, the productivity of the PVA resin tends to decrease, the biodegradability tends to decrease, and the water-soluble film tends to easily cause blocking.

[0078] When an anionic group-modified PVA resin is used as the modified PVA resin, the modification amount of the anionic group-modified PVA resin is preferably 1 to 10 mol%, more preferably 1.5 to 9 mol%, and particularly preferably 2 to 8 mol%. If the modification amount is too small, the solubility of the water-soluble film in water tends to decrease. If it is too large, the productivity of the PVA resin tends to decrease, the biodegradability tends to decrease, and the water-soluble film tends to easily cause blocking.

[0079] The average saponification degree is measured in accordance with JIS K 6726 3.5, and the viscosity of a 4 mass % aqueous solution is measured in accordance with JIS K 6726 3.11.2.

[0080] The unmodified PVA can be produced by saponifying a polyvinyl ester resin obtained by polymerizing a vinyl ester compound.

[0081] Examples of the vinyl ester compound include vinyl formate, vinyl acetate, vinyl trifluoroacetate, vinyl propionate, vinyl butyrate, vinyl caprate, vinyl laurate, vinyl versatate, vinyl palmitate, and vinyl stearate, with vinyl acetate being preferred. These vinyl ester compounds may be used alone or in combination of two or more.

[0082] As a method for polymerizing the vinyl ester compound, any known polymerization method such as solution polymerization, emulsion polymerization, and suspension polymerization can be used. Generally, the polymerization is carried out by solution polymerization using an alcohol such as methanol, ethanol, or isopropanol as a solvent.

[0083] The polymerization catalyst can be appropriately selected according to the polymerization method, for example, azo catalysts such as azobisisobutyronitrile, peroxide catalysts such as acetyl peroxide, benzoyl peroxide, and lauroyl peroxide, and other known polymerization catalysts. The polymerization reaction temperature is selected from the range of 50° C. to the boiling point.

[0084] Saponification can be carried out by a known method. Typically, the obtained copolymer is dissolved in an alcohol in the presence of a saponification catalyst. Examples of the alcohol include methanol, ethanol, and butanol. From the perspective of solubility, the concentration of the copolymer in the alcohol is selected from the range of 20 to 50% by mass.

[0085] As the saponification catalyst, a base catalyst such as an alkali metal hydroxide and / or alkoxide such as sodium hydroxide, potassium hydroxide, sodium methoxide, sodium ethoxide, potassium methoxide, etc. can be used, or an acid catalyst can be used. The amount of the saponification catalyst used is preferably 1 to 100 millimoles equivalent to the vinyl ester compound.

[0086] The modified PVA-based resin can be produced, for example, by saponifying a copolymer of a vinyl ester-based compound and an unsaturated monomer, or by post-modifying unmodified PVA.

[0087] As the vinyl ester compound, the same compounds as those in the case of the above-mentioned unmodified PVA can be used.

[0088] Examples of unsaturated monomers copolymerized with vinyl ester monomers used in the modified PVA resin obtained by copolymerization (copolymerized modified PVA resin) include: olefins such as ethylene, propylene, isobutylene, α-octene, α-dodecene, and α-octadecene; hydroxyl-containing α-olefins such as 3-butene-1-ol, 4-pentene-1-ol, and 5-hexene-1-ol, and their acylate derivatives; unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, maleic anhydride, itaconic acid, and undecenoic acid, and their salts, monoesters, or dialkyl esters; amides such as diacetone acrylamide, acrylamide, and methacrylamide; olefin sulfonic acids such as vinyl sulfonic acid, allyl sulfonic acid, and methallyl sulfonic acid, and their salts; and N-vinyl pyrrolidone. These can be used alone or in combination of two or more.

[0089] In addition, as modified PVA-based resins obtained by post-reaction (post-modified PVA-based resins), for example, there can be mentioned: those having an acetoacetyl group obtained by reaction with diketene, those having a polyalkylene oxide group obtained by reaction with ethylene oxide, those having a hydroxyalkyl group obtained by reaction with epoxy compounds, or those obtained by reacting aldehyde compounds having various functional groups with PVA-based resins through esterification, acetalization, carbamate formation, etherification, grafting, phosphate esterification, oxyalkylene formation, etc.

[0090] Modified PVA resins also include those having primary hydroxyl groups in their side chains. For example, these resins typically have 1 to 5 primary hydroxyl groups in their side chains, preferably 1 to 2, and particularly preferably 1. Furthermore, they preferably also have secondary hydroxyl groups in addition to the primary hydroxyl groups. Examples of such modified PVA resins include those having hydroxyalkyl groups in their side chains and those having 1,2-diol structural units in their side chains. Modified PVA-based resins having a 1,2-diol structural unit in a side chain can be produced, for example, by the following methods: (i) a method of saponifying a copolymer of vinyl acetate and 3,4-diacetoxy-1-butene, (ii) a method of saponifying and decarbonating a copolymer of vinyl acetate and vinyl ethylene carbonate, (iii) a method of saponifying and deketalizing a copolymer of vinyl acetate and 2,2-dialkyl-4-vinyl-1,3-dioxolane, (iv) a method of saponifying a copolymer of vinyl acetate and glycerol monoallyl ether, etc.

[0091] The copolymerization method of the vinyl ester compound and the unsaturated monomer copolymerizable with the vinyl ester compound can be the same method as that used for the unmodified PVA, typically performed by solution polymerization using an alcohol as a solvent. The polymerization catalyst, saponification method, and saponification catalyst can also be appropriately selected from those used for the unmodified PVA.

[0092] Carboxyl-modified PVA resins can be produced by any method, for example: (I) a method of copolymerizing an unsaturated monomer having a carboxyl group with a vinyl ester compound and then saponifying it; (II) a method of polymerizing a vinyl ester compound in the presence of an alcohol and / or aldehyde or thiol having a carboxyl group as a chain transfer agent and then saponifying it, etc.

[0093] As the vinyl ester compound in the above-mentioned method (I) or (II), the above-mentioned compounds can be used, and vinyl acetate is preferably used.

[0094] Examples of the unsaturated monomer having a carboxyl group in the method (I) include ethylenically unsaturated dicarboxylic acids (maleic acid, fumaric acid, itaconic acid, etc.), ethylenically unsaturated dicarboxylic acid monoesters (maleic acid monoalkyl esters, fumaric acid monoalkyl esters, itaconic acid monoalkyl esters, etc.), ethylenically unsaturated dicarboxylic acid diesters (maleic acid dialkyl esters, fumaric acid dialkyl esters, itaconic acid dialkyl esters, etc.) [however, these diesters need to be converted to carboxyl groups by hydrolysis during the saponification of the copolymer], ethylenically unsaturated carboxylic acid anhydrides (maleic acid Monomers such as (methyl)acrylic acid, ...

[0095] In the above method (II), a chain transfer agent is preferably used. As the chain transfer agent, a thiol compound having a large chain transfer effect is generally preferred, and examples thereof include the following compounds and their salts. These can be used alone or in combination of two or more.

[0096]

[0097] [In the above general formulas (1) and (2), n is an integer from 0 to 5, and R1, R2, and R3 each represent a hydrogen atom or a lower alkyl group (which may have a substituent).]

[0098]

[0099] [In the above general formula (3), n is an integer from 0 to 20.]

[0100] Specific examples include thioglycolic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, and 2-mercaptostearic acid.

[0101] It should be noted that, in addition to the above-mentioned unsaturated monomers and vinyl ester compounds having a carboxyl group, other common monomers may be contained and polymerized within a range that does not impair water solubility. Examples of these monomers include alkyl esters of ethylenically unsaturated carboxylic acids, allyl esters of saturated carboxylic acids, α-olefins, alkyl vinyl ethers, alkyl allyl ethers, (meth)acrylamide, (meth)acrylonitrile, styrene, vinyl chloride, and the like.

[0102] In addition, the method for producing the above-mentioned carboxyl-modified PVA-based resin is not limited to the above-mentioned method. For example, a method in which a carboxyl-containing compound such as dicarboxylic acid, aldehyde acid, or hydroxycarboxylic acid containing a functional group reactive with a hydroxyl group is post-reacted with polyvinyl alcohol (partially saponified or completely saponified) may also be implemented.

[0103] In addition, sulfonic acid-modified PVA-based resins can be produced, for example, by a method of copolymerizing a copolymer component such as vinyl sulfonic acid, styrene sulfonic acid, allyl sulfonic acid, methallyl sulfonic acid, or 2-acrylamide-2-methylpropanesulfonic acid with a vinyl ester compound and then saponifying the copolymer; or by a method of subjecting PVA to Michael addition of vinyl sulfonic acid or its salt, 2-acrylamide-2-methylpropanesulfonic acid or its salt, etc., etc.

[0104] From the perspective of film properties such as solubility and / or mechanical properties, the content of the PVA-based resin (A) in the water-soluble film is preferably 30% by mass or more, particularly preferably 35% by mass or more, and even more preferably 40% by mass or more. If this content is too low, the solubility in water and / or the mechanical properties of the film tend to decrease. The upper limit of this content is generally 85% by mass or less, preferably 80% by mass or less, and particularly preferably 75% by mass or less, from the perspective of shape stability over time when formed into a package.

[0105] The mass content ratio of gelatin to PVA resin (A) is preferably gelatin / PVA resin (A) of 1 / 99 to 99 / 1, particularly preferably 5 / 95 to 80 / 20, further preferably 10 / 90 to 60 / 40, and particularly preferably 15 / 85 to 45 / 55.

[0106] If the gelatin content is too high, compatibility with the PVA-based resin (A) tends to deteriorate, and the solubility of the film in water may decrease. In addition, mechanical properties such as film strength tend to decrease.

[0107] <Plasticizer>

[0108] In order to impart moderate flexibility to the film, the present water-soluble film preferably contains a plasticizer in addition to gelatin and PVA-based resin (A). A single plasticizer may be used alone or in combination of two or more. From the perspective of the film's mechanical properties and / or formability, a combination of two or more is also preferred.

[0109] Examples of the plasticizer include glycerols such as glycerol, diglycerol, and triglycerol; alkylene glycols such as diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, and dipropylene glycol; and / or sugar alcohols such as trimethylolpropane, sorbitol, xylitol, and / or maltitol. These can be used alone or in combination of two or more. Of these, glycerol, diglycerol, and polyethylene glycol are preferred due to their ease of availability and ability to achieve a plasticizing effect in small amounts. Furthermore, sorbitol is preferred due to its improved stability over time. A combination of glycerol and sorbitol is also preferred.

[0110] The content of the plasticizer is preferably 10 to 60 parts by mass, particularly preferably 15 to 55 parts by mass, further preferably 18 to 50 parts by mass, and particularly preferably 20 to 45 parts by mass, relative to 100 parts by mass of the total of gelatin and PVA-based resin (A). If the content of the plasticizer is too low, the plasticizing effect tends to be low, processability tends to be reduced, or the toughness of the water-soluble film formed into a package tends to be impaired over time. If the content is too high, the strength of the film tends to be reduced, or blocking tends to occur.

[0111] <Padding>

[0112] The present water-soluble film may contain a filler as needed.

[0113] The fillers are included to improve anti-blocking properties. These fillers are not particularly limited and can be either organic or inorganic fillers, with organic fillers being particularly preferred. These fillers can be used alone or in combination of two or more. The average particle size of the fillers is preferably 0.1 to 50 μm, particularly preferably 1 to 35 μm.

[0114] The average particle size of the filler is a value measured using a laser diffraction particle size distribution analyzer and calculated from the D50 value (particle size at 50% cumulative volume) of the obtained cumulative volume distribution.

[0115] The organic filler refers to a granular substance (primary particle) in any shape such as needle-like, rod-like, lamellar, scaly, or spherical, or an aggregate of the granular substance (secondary particle) composed of an organic compound.

[0116] The organic filler is mainly selected from polymer compounds, and examples thereof include melamine-based resins, polymethyl (meth)acrylate-based resins, and polystyrene-based resins, as well as biodegradable resins such as starch and polylactic acid. Among them, biodegradable resins such as polymethyl (meth)acrylate-based resins, polystyrene-based resins, and starch are preferred, and starch is particularly preferred from the viewpoint of dispersibility in the PVA-based resin (A).

[0117] Examples of the starch include raw starch (corn starch, potato starch, sweet potato starch, wheat starch, cassava starch, sago starch, tapioca starch, sorghum starch, rice starch, bean starch, kudzu root starch, bracken starch, lotus seed starch, water chestnut starch, etc.), physically modified starch (α-starch, isolated amylose, heat-moisture-treated starch, etc.), enzyme-modified starch (hydrolyzed dextrin, enzyme-decomposed dextrin, amylose, etc.), chemically decomposed modified starch (acid-treated starch, hypochlorous acid-oxidized starch, dialdehyde starch, etc.), and chemically modified starch derivatives (esterified starch, etherified starch, cationized starch, cross-linked starch, etc.). Of these, raw starch is preferably used, and corn starch and rice starch are particularly preferred from the perspectives of availability and / or cost-effectiveness.

[0118] The average particle size of the organic filler is preferably 3 to 50 μm, particularly preferably 5 to 40 μm, and even more preferably 10 to 35 μm. If the average particle size is too small, the film's blocking properties tend to increase. If it is too large, the fillers tend to aggregate, reducing dispersibility or forming pinholes during film stretching during film forming.

[0119] The inorganic filler refers to a particulate material (primary particle) in any shape such as needle-like, rod-like, layer-like, scale-like, or spherical, or an aggregate of the particulate material (secondary particle) composed of an inorganic compound.

[0120] Examples of the inorganic filler include oxide-based inorganic compounds such as silica, diatomaceous earth, titanium dioxide, calcium oxide, magnesium oxide, aluminum oxide, barium oxide, germanium dioxide, tin oxide, and zinc oxide, and / or talc, clay, kaolin, mica, asbestos, gypsum, graphite, glass spheres, glass beads, calcium sulfate, barium sulfate, ammonium sulfate, calcium sulfite, calcium carbonate, whisker-like calcium carbonate, magnesium carbonate, dawsonite, dolomite, potassium titanate, carbon black, glass fiber, alumina fiber, boron fiber, processed mineral fiber, carbon fiber, hollow carbon spheres, bentonite, montmorillonite, copper powder, sodium sulfate, potassium sulfate, zinc sulfate, copper sulfate, iron sulfate, magnesium sulfate, aluminum sulfate, potassium aluminum sulfate, ammonium nitrate, sodium nitrate, potassium nitrate, aluminum nitrate, ammonium chloride, sodium chloride, potassium chloride, magnesium chloride, calcium chloride, sodium phosphate, and potassium chromate. These can be used alone or in combination of two or more.

[0121] Among them, silica, oxide-based inorganic compounds, and talc are preferably used, silica, titanium oxide, and talc are particularly preferably used, and silica is further preferably used.

[0122] The average particle size of the inorganic filler is preferably 1 to 20 μm, particularly preferably 2 to 15 μm, and even more preferably 3 to 10 μm. If the average particle size is too small, the flexibility and / or toughness of the film tends to decrease, or the blocking property tends to increase. If the average particle size is too large, pinholes tend to form when the film is stretched during molding.

[0123] The content of the filler is preferably 1 to 30 parts by mass, particularly preferably 2 to 25 parts by mass, and even more preferably 2.5 to 20 parts by mass, relative to 100 parts by mass of gelatin and PVA-based resin (A). If the content is too low, the blocking property tends to increase, while if it is too high, the flexibility and / or toughness of the film tends to decrease.

[0124] In addition, from the perspective of the balance between the anti-blocking properties and the mechanical properties and / or sealing properties of the film, it is preferably contained in an amount of 12 parts by mass or less, particularly preferably 1 to 11 parts by mass, further preferably 2 to 10 parts by mass, and particularly preferably 2.5 to 9 parts by mass, relative to 100 parts by mass of the PVA-based resin (A).

[0125] <Surfactant>

[0126] The present water-soluble film may further contain a surfactant or the like as needed.

[0127] The surfactant is contained for the purpose of improving the releasability from the casting surface during film production, and generally includes nonionic surfactants, cationic surfactants, and anionic surfactants.

[0128] Examples of such surfactants include polyoxyethylene nonylphenyl ether, polyoxyethylene octylnonyl ether, polyoxyethylene dodecylphenyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate, polyoxyethylene alkylamine ethers such as polyoxyethylene alkyl ether phosphate monoethanolamine salt, polyoxyethylene laurylamine ether, and polyoxyethylene stearylamine ether, sorbitan monopalmitate, sorbitan monostearate, stearic acid glyceryl ester, and sucrose fatty acid esters. These surfactants may be used alone or in combination of two or more. Among them, polyoxyethylene alkylamine ether phosphate monoethanolamine salt and polyoxyethylene laurylamine ether are preferred from the viewpoint of manufacturing stability. These surfactants may be used alone or in combination of two or more.

[0129] The content of the surfactant is preferably 0.01 to 3 parts by mass, particularly preferably 0.05 to 2.5 parts by mass, and even more preferably 0.1 to 2 parts by mass, relative to 100 parts by mass of gelatin and PVA-based resin (A). If the content is too low, the peelability between the casting surface of the film-forming apparatus and the resulting film is reduced, tending to reduce productivity. If the content is too high, blocking tends to occur, and the adhesive strength during sealing of a package formed using the film tends to decrease.

[0130] <Other ingredients>

[0131] The present water-soluble film may contain, as other components other than the PVA-based resin (A), other water-soluble polymers (e.g., sodium polyacrylate, polyethylene oxide, polyvinyl pyrrolidone, dextrin, chitosan, chitin, methylcellulose, hydroxyethylcellulose, etc.), fragrances, rust inhibitors, colorants, extenders, defoamers, ultraviolet absorbers, liquid paraffins, fluorescent whitening agents, bittering ingredients (e.g., denatonium benzoate, etc.), etc., within the scope not hindering the purpose of the invention. These may be used alone or in combination of two or more.

[0132] The content of the above-mentioned other components is preferably 5 parts by mass or less, particularly preferably 1 part by mass or less, and further preferably 0.5 parts by mass or less per 100 parts by mass of the PVA-based resin (A). The lower limit is usually 0 parts by mass. If this content is too high, compatibility with gelatin decreases, and a tendency to reduce durability is observed.

[0133] The present water-soluble film may also contain an antioxidant. Examples of such antioxidants include sulfites such as sodium sulfite, potassium sulfite, calcium sulfite, and ammonium sulfite, tartaric acid, ascorbic acid, sodium thiosulfate, catechol, and Rongalite. Sulfites are preferred, with sodium sulfite being particularly preferred. The amount of such antioxidants added is preferably 0.1 to 10 parts by mass, particularly preferably 0.2 to 5 parts by mass, and even more preferably 0.3 to 3 parts by mass per 100 parts by mass of the PVA-based resin (A).

[0134] <<Manufacturing of Water-Soluble Film>>

[0135] In the present water-soluble film, gelatin and a PVA-based resin (A) are blended as described above, preferably further blended with a plasticizer, and optionally blended with other components such as fillers and surfactants, dissolved or dispersed in water to prepare a film-forming raw material, which is then formed into a film. The production of this water-soluble film includes a casting step of casting the film-forming raw material onto a casting surface, and a drying step of drying the cast film-forming raw material.

[0136] <Dissolution Process>

[0137] In the dissolving step, the components blended above are dissolved or dispersed in water to prepare an aqueous solution or aqueous dispersion serving as a membrane-forming raw material.

[0138] When preparing the film-forming raw materials, the mixing method of gelatin, PVA-based resin (A) and other additives is not particularly limited. For example, the following methods can be mentioned: (i) a method of mixing gelatin, PVA-based resin (A) and other additives to form a mixture, and mixing the mixture with water to dissolve it; (ii) a method of dissolving PVA-based resin (A) and other additives in water and then mixing gelatin; (iii) a method of dissolving gelatin, PVA-based resin (A) and other additives separately in water and then mixing them; (iv) a method of dissolving gelatin and PVA-based resin (A) separately in water and then mixing and dissolving them with other additives, etc.

[0139] As a dissolution method for dissolving in water, room temperature dissolution, high temperature dissolution, pressure dissolution, etc. are generally used. Among them, high temperature dissolution and pressure dissolution are preferred from the viewpoint of less undissolved matter and excellent productivity.

[0140] The dissolution temperature is generally 80 to 100° C., preferably 90 to 100° C., for high-temperature dissolution, and generally 80 to 130° C., preferably 90 to 120° C. for pressure dissolution. In particular, the dissolution temperature of gelatin is preferably 50 to 90° C., particularly preferably 55 to 85° C., and even more preferably 60 to 80° C.

[0141] The dissolution time is usually 1 to 20 hours, preferably 2 to 15 hours, and more preferably 3 to 10 hours. If the dissolution time is too short, undissolved matter tends to remain, while if it is too long, productivity tends to decrease.

[0142] Furthermore, after dissolution, the obtained film-forming raw material is subjected to a degassing treatment. Examples of the degassing method include static degassing, vacuum degassing, and twin-screw extrusion degassing. Among them, static degassing and twin-screw extrusion degassing are preferred.

[0143] The degassing temperature is generally 50 to 100° C., preferably 55 to 95° C., and particularly preferably 60 to 80° C. If the degassing temperature is too high, the protein component of gelatin is denatured, causing coloration and / or reduced strength. If the degassing temperature is too low, the viscosity increases, degassing takes time, and productivity tends to decrease.

[0144] The defoaming time is usually 2 to 30 hours, preferably 5 to 25 hours.

[0145] The solid content concentration of the film-forming raw material is preferably 10 to 60% by mass, particularly preferably 12 to 50% by mass, and even more preferably 15 to 40% by mass. If the concentration is too low, the film productivity tends to decrease, while if it is too high, the viscosity becomes too high, degassing of the film-forming raw material takes time, or die lines tend to form during film formation.

[0146] The pH of the membrane-forming raw material is usually 4 to 8, preferably 4.8 to 7.5.

[0147] <Film Forming Process>

[0148] In the film forming step, the film forming raw material prepared in the dissolving step is formed into a film shape and, if necessary, dried to prepare a water-soluble thin film having a specific water content.

[0149] As a film forming method, for example, a melt extrusion method and / or a casting method can be adopted. From the viewpoint of the accuracy of the film thickness, the casting method is preferred.

[0150] When the casting method is carried out, for example, the above-mentioned film-making raw material is discharged from a slit such as a T-type slit die, cast on a casting surface such as the surface of a plastic substrate such as a polyethylene terephthalate film, etc., such as the metal surface of an endless belt and / or a drum roller, dried, and further heat-treated as needed, thereby making it possible to produce a water-soluble film.

[0151] During the film forming process, the water-soluble film peeled from the casting surface, such as the surface of the plastic substrate, is conveyed and wound onto a core tube to form a film roll. The resulting film roll can be supplied as a product directly, but it is also preferably supplied as a film roll obtained by slitting the water-soluble film to the desired film width.

[0152] The surface of the obtained water-soluble film can be flat, but from the perspective of anti-blocking, slippage during processing, reduction of adhesion between products and appearance, it is also preferred to pre-process one or both sides of the film with embossing patterns and / or fine concave-convex patterns, special engraving patterns, etc.

[0153] The thickness of the water-soluble film can be appropriately selected depending on the intended use, but is preferably 10 to 120 μm, particularly preferably 15 to 110 μm, and even more preferably 20 to 100 μm. If the thickness is too thin, the mechanical strength of the film tends to decrease, while if it is too thick, the dissolution rate in water tends to slow, and the film-forming efficiency tends to decrease.

[0154] The width of the water-soluble film can be appropriately selected according to the application, and is preferably 300 to 5000 mm, particularly preferably 500 to 4000 mm, and further preferably 600 to 3000 mm. If the width is too narrow, productivity tends to decrease, while if it is too wide, slack and / or film thickness control tends to become difficult.

[0155] The length of the water-soluble film can be appropriately selected depending on the intended use, but is preferably 100 to 20,000 m, particularly preferably 800 to 15,000 m, and even more preferably 1,000 to 10,000 m. If the length is too short, film replacement requires time and effort, which tends to reduce productivity. If the length is too long, winding tightens, resulting in a poor appearance.

[0156] From the perspective of mechanical strength and / or heat sealability, the water content of this water-soluble film is preferably 3-15% by mass, particularly preferably 5-9% by mass, and even more preferably 6-8% by mass. If the water content is too low, the film becomes too hard, which tends to reduce the formability and / or impact resistance of the packaged product. If the water content is too high, it tends to cause blocking. Adjusting the water content can be achieved by appropriately setting the drying and / or humidity control conditions.

[0157] In addition, the said water content is measured based on JIS K 6726 3.4, and the value of the volatile matter obtained is made into the water content.

[0158] The present water-soluble film can suppress the time-dependent decrease in the solubility of the film when packaging neutral to weakly alkaline liquid detergents, so that the rate of increase in the dissolution time of the film when the water-soluble film is left in static contact for 3 weeks in a mixed solution of 6.2% by mass of propylene glycol, 10.9% by mass of glycerin, 7.6% by mass of ethanolamine, 12.5% ​​by mass of water, and pH 7.5 is preferably less than 70%, particularly preferably less than 65%, further preferably less than 60%, and particularly preferably less than 50%.

[0159] The present water-soluble film may be used as a single layer or in the form of a multilayer structure in which other films and / or resin layers are laminated.

[0160] This water-soluble film is particularly useful for packaging pesticides and / or detergents (unit packaging) and edibles (food packaging). Foods packaged with the film can be in the form of granules, tablets, powders, etc., and are also preferably used for dry foods such as instant food ingredients and ingredients.

[0161] <<Medicine packaging>>

[0162] A pharmaceutical package according to one embodiment of the present invention (hereinafter sometimes referred to as the "present package") comprises a pharmaceutical covered with a packaging body comprising the obtained water-soluble film. Since the pharmaceutical is packaged with the packaging body comprising the water-soluble film, when the pharmaceutical and the packaging body are placed in water, the packaging body (the water-soluble film) on the surface dissolves, revealing the pharmaceutical, which then dissolves or disperses in the water, demonstrating its effectiveness. Therefore, the present package is suitable for packaging relatively small amounts of pharmaceuticals, such as a single dose.

[0163] Examples of the above-mentioned agents include pesticides such as insecticides, fungicides, and herbicides, fertilizers, and detergents. Detergents such as cleaning detergents and dishwashing detergents are particularly preferred. Such agents may be liquid or solid. Examples of solid forms include granules, tablets, and powders. The agent is preferably one that dissolves or disperses in water, with liquid detergents being particularly preferred. The pH of such agents may be alkaline, neutral, or acidic.

[0164] The pH of the liquid detergent when dissolved or dispersed in water at a concentration of 1% by mass is preferably 6 to 12, particularly preferably 6 to 10, further preferably 6.5 to 9, and particularly preferably 7 to 8. The water content of the liquid detergent is preferably 15% by mass or less, particularly preferably 0.1 to 10% by mass, and further preferably 0.1 to 7% by mass. When the water content of the liquid detergent is within this range, the water-soluble film does not gel or become insoluble, and excellent water solubility is observed.

[0165] The pH value is measured in accordance with JIS K 3362 8.3, and the water content is measured in accordance with JIS K 3362 7.21.3.

[0166] <<Manufacturing of Pharmaceutical Packages>>

[0167] To package a liquid detergent or other medicine using a water-soluble film to form a medicine package, a known method can be used.

[0168] For example, a drug packaging body can be manufactured by the following steps: preparing a first water-soluble film, a second water-soluble film and a drug, making the first water-soluble film and the second water-soluble film face each other so as to sandwich the drug, and making the first water-soluble film and the second water-soluble film partially abut each other; and pressing the abutting parts of the first water-soluble film and the second water-soluble film together.

[0169] Specifically, a film (base film) is fixed to a lower mold of a molding device, and the base film is molded into a shape along the lower mold (a shape in which a drug can be placed).

[0170] Meanwhile, a film (top film) is also secured to the upper mold of the molding apparatus. A separately prepared liquid detergent or other pharmaceutical product is then placed (dropped) into the molded bottom film. The molds are then pressed together to bring the top and bottom films into contact, and the contacting portions are compressed under vacuum. After compression, the vacuum is released, resulting in a pharmaceutical package in which the pharmaceutical product is enclosed in the water-soluble film.

[0171] Examples of the method for pressure-bonding the film include heat sealing, water sealing, and glue sealing. Among them, water sealing is preferably used because it is easy to control the pressure-bonding conditions.

[0172] Example

[0173] Hereinafter, the present invention will be described in more detail with reference to Examples. However, the present invention is not limited to the following Examples unless it exceeds the gist of the present invention.

[0174] It should be noted that, in the examples, "parts" refers to a mass basis.

[0175] As material components of the water-soluble film, the following substances were prepared.

[0176] (gelatin)

[0177] (1) Nitta Gelatin Co., Ltd. "#200": Alkali treatment

[0178] (2) “Gelatin 21” manufactured by Nitta Gelatin Co., Ltd.: Alkali treatment

[0179] (3) Nitta Gelatin Co., Ltd. "FGL-250TS": Acid treatment

[0180] (PVA-based resin (A))

[0181] Modified PVA resin (a1): a carboxyl-modified PVA resin having a 4% aqueous solution viscosity of 22 mPa·s at 20°C, an average saponification degree of 94 mol%, and a modification amount of 2.0 mol% based on monomethyl maleate.

[0182] Unmodified PVA resin (a2): 4% aqueous solution viscosity at 20°C 43 mPa·s, average saponification degree 88 mol%

[0183] (Plasticizer)

[0184] Plasticizer (b1): sorbitol

[0185] Plasticizer (b2): glycerol

[0186] (Other additives)

[0187] Filler: starch (average particle size 20 μm)

[0188] Surfactant: Polyoxyalkylene alkyl ether phosphate monoethanolamine salt

[0189] [Example 1]

[0190] 30 parts of gelatin, 70 parts of anionic group-modified PVA-based resin (a1) as PVA-based resin (A), 20 parts of sorbitol (b1) as plasticizer (B), 20 parts of glycerol (b2), 0.2 parts of polyoxyalkylene alkyl ether phosphate monoethanolamine salt as surfactant, and water were mixed and dissolved to obtain a film-forming raw material in the form of an aqueous dispersion of the resin composition having a solid content concentration of 25%. The obtained film-forming raw material was allowed to stand at 60°C for 24 hours for degassing.

[0191] The film-forming raw material after static degassing was cast on a polyethylene terephthalate film and passed through a 3 m long drying chamber (105° C.) at a speed of 0.440 m / min and dried to obtain a water-soluble film with a thickness of 87 μm (water content: 7% by mass).

[0192] The obtained water-soluble film was used to evaluate compatibility, solubility, mechanical properties, and water-tightness according to the methods described below.

[0193] <Compatibility>

[0194] [Evaluation method]

[0195] The presence of a sea-island structure in the water-soluble film was observed using a laser microscope and evaluated based on the following criteria.

[0196] [Evaluation Criteria]

[0197] ○ (very good)···There is little sea-island structure, and phase separation is hardly observed.

[0198] × (poor)···The islands in the sea-island structure are large and phase separation is obvious.

[0199] <Solubility>

[0200] [Evaluation method]

[0201] The water-soluble film obtained above was cut into a size of 35 mm × 35 mm, placed in a 1-liter beaker filled with water (1 liter), and fixed with a jig. While stirring with a stirrer (rotor length 30 mm, rotation speed 750 rpm) while maintaining the water temperature at 20°C, the film was considered dissolved if no dispersion of insoluble particles with a diameter of 1 mm or more was observed. The time required for dissolution was evaluated based on the following criteria.

[0202] [Evaluation Criteria]

[0203] ○ (very good)···Dissolved in less than 90 seconds.

[0204] △ (good)···Dissolved in 90 to 300 seconds.

[0205] × (poor)···Not dissolved even after more than 300 seconds.

[0206] <Mechanical Properties>

[0207] [Evaluation method]

[0208] The water-soluble film obtained above was used to measure tensile strength and tensile elongation in accordance with JIS K 7127. Specifically, the film was allowed to stand for 24 hours under controlled humidity conditions of 23°C and 50% RH before measurement. The film was then measured for tensile strength and tensile elongation using an Autograph AG-X Plus (manufactured by Shimadzu Corporation) at a tensile speed of 200 mm / min (film width 15 mm, chuck distance 50 mm). These measured values ​​were evaluated based on the following criteria.

[0209] [Evaluation Criteria]

[0210] ○ (Very good)···The tensile strength is 10 MPa or more, and the tensile elongation exceeds 300%.

[0211] Δ (good)···The tensile strength is 10 MPa or more, and the tensile elongation is 200 to 300%.

[0212] × (poor)···The tensile strength is 0 to less than 10 MPa and / or the tensile elongation is less than 200%.

[0213] <Water tightness>

[0214] [Evaluation method]

[0215] The water-soluble film obtained above was cut into pieces measuring 100 mm x 200 mm (top film) and 100 mm x 100 mm (bottom film) and subjected to a water-tightness test. Specifically, the water-soluble film was allowed to stand for 24 hours under humidity conditions of 23°C and 40% RH. Under this environment, the water-soluble film (bottom film) was then mounted on a 30 cm square glass plate and water was applied using a PVA sponge roller ("Cygnus Roller" manufactured by AION). The water-soluble film (top film) was then placed on the water-coated water-soluble film (bottom film). Another rubber roller (250 mm width, 60 mm diameter, 2750 g weight) was then rolled over the top film twice to press the top and bottom films together, thereby producing test pieces.

[0216] After 2 minutes, the peel strength of the seal was measured using an Autograph AG-X Plus (Shimadzu Corporation) at a tensile speed of 100 mm / min (film width 15 mm, chuck distance 20 mm). The seal failure state during the watertight test and the average test force over a stroke of 50 to 100 mm were evaluated based on the following criteria.

[0217] [Evaluation Criteria]

[0218] ○ (Very good)···The average test force is 5N / 15mm or more, and cohesive failure occurs in the water seal portion.

[0219] ○ (Good)···The average test force was 5 N / 15 mm or more, and interface peeling occurred in the water-sealed portion.

[0220] ×(Poor)···The average test force is less than 5N / 15mm.

[0221] <Examples 2 to 6, Comparative Example 1>

[0222] A water-soluble film was obtained in the same manner as in Example 1 except that the changes were made as shown in Table 1. The obtained water-soluble film was evaluated in the same manner as in Example 1. The results are shown in Table 1 below.

[0223] [Table 1]

[0224]

[0225] The water-soluble films of Examples 1 to 6 containing gelatin and modified PVA resins showed good compatibility between gelatin and PVA resins and excellent solubility. Furthermore, they also showed excellent mechanical properties and / or water-tightness, making them suitable for packaging applications.

[0226] On the other hand, it was found that the water-soluble film of Comparative Example 1, which did not contain a modified PVA-based resin as the PVA-based resin, had poor compatibility with gelatin, poor solubility and / or mechanical properties, and was not suitable for practical use.

[0227] <Production of packaging>

[0228] The water-soluble films of Examples 2, 4, and 5 obtained above were used to produce packaging bodies using a packaging body manufacturing machine manufactured by Engel Co., Ltd. in accordance with the following procedure.

[0229] That is, the water-soluble film is left to stand for 24 hours under 23°C and 40% RH humidity conditioning conditions for humidity conditioning. Under this environment, a PVA-based water-soluble film (bottom film) is fixed on a mold (molded package body: 45 mm in length, 42 mm in width, and 30 mm in height) located at the bottom of the device, and a PVA-based water-soluble film (top film) is also fixed on the top of the device. The bottom film is heated for 4 seconds in a dryer that generates 70°C hot air, and the bottom film is vacuum-formed into a mold. Then, 25 mL of a commercially available liquid laundry detergent (composition summary: containing 11% by mass of propylene glycol, 7.5% by mass of glycerin, 67% by mass of surfactant, 14.2% by mass of water, pH 7.5 (stock solution)) is added to the shaped water-soluble film. 0.25 g of water is applied to the entire surface of the top film (80 mm in length and 140 mm in width), and the top film and the bottom film are pressed together for 10 seconds before the vacuum is released to produce a package body.

[0230] The obtained packaging bodies were used to evaluate the compressive strength of the packaging bodies and the solubility of the film over time according to the methods described below. The results are shown in Table 2.

[0231] <Compressive Strength>

[0232] [Evaluation method]

[0233] The package produced by the above method was measured for compressive strength when the package was broken 1 hour after production using an Autograph AG-X Plus (manufactured by Shimadzu Corporation) at a test speed of 200 mm / min. Note that a 5 kN load cell was used.

[0234] [Evaluation Criteria]

[0235] ○ (very good)···Compression strength is greater than 500N.

[0236] △ (good)···Compression strength is 200 to 500N.

[0237] × (Poor)···The compression strength is less than 200N and the bag is easily broken.

[0238] <Solubility over time>

[0239] [Evaluation method]

[0240] According to the above-mentioned packaging body production steps, a packaging body manufacturing machine manufactured by Engel is used to produce packaging bodies in which liquid detergents for clothes of various pH values ​​are wrapped with a water-soluble film (composition summary of detergent 1: contains 6.2 mass% propylene glycol, 10.9 mass% glycerol, 7.6 mass% ethanolamine, 12.5 mass% water, pH 7.0 (stock solution)) (composition summary of detergent 2: contains 11.2 mass% propylene glycol, 13.4 mass% glycerol, 8.4 mass% ethanolamine, 11.8 mass% water, pH 9.5 (stock solution)).

[0241] The package was placed in a constant temperature and humidity chamber at 37°C and 70% RH, with the water-soluble film in contact with the detergent, for 3 weeks. The liquid detergent adhering to the film was then wiped off, and a solubility test of the film at 20°C was performed in the same manner as the above-mentioned solubility measurement.

[0242] [Evaluation Criteria]

[0243] The rate of increase in the time required for dissolution of the water-soluble film was determined as follows to evaluate the solubility over time.

[0244] Increase rate (%) = [{Time required for film dissolution after 3 weeks (sec)} - {Time required for water-soluble film dissolution during packaging (sec)}] / Time required for water-soluble film dissolution during packaging (sec)

[0245] (Detergent 1: pH 7.0)

[0246] ○ (very good)···The increase rate is less than 70%.

[0247] △ (good)···The increase rate is 70 to 100%.

[0248] ×(difference)···The increase rate is greater than 100%.

[0249] (Detergent 2: pH 9.5)

[0250] ○ (very good)···The increase rate is less than 70%.

[0251] △ (good)···The increase rate is 70 to 100%.

[0252] ×(difference)···The increase rate is greater than 100%.

[0253] [Table 2]

[0254]

[0255] It is found that the water-soluble films of Examples 2, 4, and 5 containing gelatin and modified PVA-based resins have sufficient compressive strength when formed into packages and are suitable for use in liquid medicine packaging and / or food packaging.

[0256] Furthermore, it was found that the solubility of the film does not decrease over time even when packaging liquid detergents, and in particular, does not decrease over time even when packaging neutral to weakly alkaline detergents, making the film suitable for packaging liquid detergents.

[0257] The above embodiments show specific aspects of the present invention, but the above embodiments are merely illustrative and are not to be construed as limiting. Various modifications obvious to those skilled in the art are to be considered within the scope of the present invention.

[0258] Industrial applicability

[0259] The water-soluble film of the present invention can be used for packaging (unit packaging) of pesticides and / or detergents, transfer films, sanitary products such as sanitary napkins / diapers, waste disposal products such as ostomy bags, medical products such as blood-absorbing sheets, temporary substrates such as seedling sheets / seed tapes / embroidery base fabrics, etc.

[0260] Furthermore, the film of the present invention, which is a blend film of a natural raw material and a PVA-based resin also used in food and / or pharmaceuticals, is also useful in edible applications (food packaging) and cosmetic packaging applications.

Claims

1. A water-soluble film comprising gelatin and a polyvinyl alcohol-based resin A, wherein the polyvinyl alcohol-based resin A comprises a modified polyvinyl alcohol-based resin.

2. The water-soluble film according to claim 1, wherein The modified polyvinyl alcohol-based resin contains at least one modified polyvinyl alcohol-based resin selected from the group consisting of anionic group-modified polyvinyl alcohol, pyrrolidone ring group-modified polyvinyl alcohol, and amino group-modified polyvinyl alcohol. The water-soluble film according to claim 1 or 2, further comprising a plasticizer. 4 . The water-soluble film according to claim 1 , wherein the water content is 3 to 15% by mass. The water-soluble film according to any one of claims 1 to 4, which is used for pharmaceutical packaging.

6. The water-soluble film according to any one of claims 1 to 5, wherein When the water-soluble film is allowed to stand in contact with a mixed solution of 11.2% by mass of propylene glycol, 13.4% by mass of glycerol, 8.4% by mass of ethanolamine, and 11.8% by mass of water at pH 9.5 for 3 weeks, the increase in dissolution time of the film is less than 70%.

7. The water-soluble film according to any one of claims 1 to 6, wherein When the water-soluble film is allowed to stand in contact with a mixed solution of 6.2% by mass of propylene glycol, 10.9% by mass of glycerol, 7.6% by mass of ethanolamine, and 12.5% ​​by mass of water at pH 7.0 for 3 weeks, the increase in dissolution time of the film is less than 70%. 8 . A medicine package comprising a package and a medicine enclosed in the package, wherein the package comprises the water-soluble film according to claim 1 .

9. The medicine package according to claim 8, wherein: The medicament is a liquid detergent.

10. The medicine package according to claim 9, wherein: The pH value of the liquid detergent when dissolved or dispersed in water is 6 to 9.

11. A method for producing a water-soluble film, which is a method for producing the water-soluble film according to any one of claims 1 to 7, comprising: a casting step of preparing a film-forming raw material containing gelatin and a modified polyvinyl alcohol-based resin, and casting the film-forming raw material on a casting surface; and a drying step of drying the cast film-forming raw material.

12. A method for manufacturing a drug packaging body, which is a method for manufacturing a drug packaging body according to any one of claims 8 to 10, comprising: preparing a first water-soluble film, a second water-soluble film and a drug, making the first water-soluble film and the second water-soluble film face each other so as to sandwich the drug, and making the first water-soluble film and the second water-soluble film partially abut each other; and a process of pressing the abutting parts of the first water-soluble film and the second water-soluble film together.

Images