JP6888256B2 - Water-soluble film and drug packaging - Google Patents

Description

The present invention relates to a water-soluble film (hereinafter, may be referred to as PVA-based film) containing a polyvinyl alcohol-based resin (hereinafter, polyvinyl alcohol may be abbreviated as PVA) as a main component. More specifically, the water-soluble film has excellent mechanical properties such as high tensile strength and high tensile elongation. In particular, the water-soluble film over time even when a liquid such as a liquid detergent is packaged into a package. It relates to a water-soluble film capable of forming a good package without impairing the tension of the film and a drug package made by using the film.

The PVA-based film is a film made of a PVA-based resin that is a thermoplastic resin but has water solubility, and a hydrophobic film that is usually often used for packaging films such as polyethylene terephthalate films and polyolefin films is a film. The physical properties and the feel of the film are significantly different.

Conventionally, it has been proposed to take advantage of the water solubility of PVA-based resin to package various chemicals such as pesticides and detergents in a bag made of PVA-based resin film (unit packaging), and use it for a wide range of purposes. Has been done.

As a water-soluble unit packaging bag used for such applications, for example, 5 to 30 parts by weight of a plasticizer, 1 to 10 parts by weight of starch, and 0.01 to 2 parts by weight of a surfactant are blended with 100 parts by weight of PVA. A water-soluble film (see, for example, Patent Document 1), a 4% by weight aqueous solution viscosity at 20 ° C. of 10 to 35 mPa · s, an average saponification degree of 80.0 to 99.9 mol%, and an anionic group modification amount of 1 to 1 With respect to 100 parts by weight of 10 mol% anionic group-modified PVA resin (A), 20 to 50 parts by weight of the plasticizer (B), 2 to 30 parts by weight of the filler (C), and 0. A water-soluble film (see, for example, Patent Document 2) made of a resin composition containing 01 to 2.5 parts by weight is known.

Japanese Unexamined Patent Publication No. 2001-329130 Japanese Unexamined Patent Publication No. 2004-161823

However, the water-soluble films disclosed in Patent Documents 1 and 2 are excellent in water solubility and can be used as a drug package for packaging a liquid detergent or the like, but on the other hand, when stored as a package. A water-soluble film that loses its tension over time and may result in a package that does not look and feel good, and can form a good package that does not impair the tension of the water-soluble film over time. Was desired.

Therefore, in the present invention, under such a background, the water-soluble film has excellent mechanical properties such as high tensile strength and high tensile elongation, and in particular, it is in a state of packaging a liquid such as a liquid detergent to form a package. It is an object of the present invention to provide a water-soluble film capable of forming a good package without impairing the tension of the water-soluble film over time, and a drug package obtained by packaging various drugs with the water-soluble film. Is what you do.

However, as a result of diligent research in view of such circumstances, the present inventors have used water-soluble films mainly composed of PVA-based resins in combination with those having a high melting point and those having a low melting point, and further compare the amounts of the plasticizing agents. By containing a large amount of the film, the water-soluble film has excellent mechanical properties such as high tensile strength and high tensile elongation without impairing the water solubility of the film. The present invention has been completed by finding that it is possible to obtain a water-soluble film capable of forming a good package without impairing the tension of the water-soluble film over time even in such a state.

That is, the gist of the present invention is a water-soluble film containing a PVA-based resin (A) and a plasticizer (B), wherein the PVA-based resin (A) is an anionic group-modified PVA-based resin and unmodified. The plasticizer (B) contains polyvinyl alcohol and contains a polyhydric alcohol (b1) having a melting point of 80 ° C. or higher and a polyhydric alcohol (b2) having a melting point of 50 ° C. or lower. the content is 25 to 50 wt parts with respect to PVA-based resin (a) 100 parts by weight of a polyhydric alcohol having a melting point at 80 ° C. or higher (b1), polyhydric melting point of 50 ° C. or less It relates to a water-soluble film having an alcohol (b2) content ratio (b1 / b2) of 0.5 to 5 by weight.

Furthermore, the present invention also provides a drug package made of the water-soluble film.

The water-soluble film of the present invention has excellent water solubility, and also has excellent mechanical properties such as high tensile strength and high tensile elongation of the water-soluble film. It is a water-soluble film that can form a good packaging without impairing the tension of the water-soluble film over time even in the state of being used, and can be used for various packaging applications, especially for unit packaging applications such as chemicals. It is useful.

The content ratio (b1 / b2) of the polyhydric alcohol (b1) having a melting point of 80 ° C. or higher and the polyhydric alcohol (b2) having a melting point of 50 ° C. or lower in the plasticizer (B) is 0. because 5 is 5, the blocking does not occur, can be a water-soluble film that does not brittle even under low humidity environment.

Further, when the number of hydroxyl groups in one molecule of the polyhydric alcohol (b1) having a melting point of 80 ° C. or higher is 4 or more, the compatibility with the PVA-based resin is excellent.

Further, when the polyhydric alcohol (b1) having a melting point of 80 ° C. or higher has a molecular weight of 150 or higher, the tension of the water-soluble film is more excellent.

When the number of hydroxyl groups in one molecule of the polyhydric alcohol (b2) having a melting point of 50 ° C. or lower is 4 or less, the flexibility can be easily controlled near room temperature (25 ° C.). ..

Further, when the polyhydric alcohol (b2) having a melting point of 50 ° C. or lower has a molecular weight of 100 or less, the flexibility is more easily controlled.

Further, since the PVA-based resin (A) contains both anionic group-modified PVA-based resin and unmodified PVA, so the water sealability is more excellent.

When the water content of the water-soluble film is 3 to 15% by weight, the mechanical strength and the sealing property are improved.

Hereinafter, the present invention will be specifically described.
The water-soluble film of the present invention contains a PVA-based resin (A) and a plasticizer (B).
First, the PVA-based resin (A) used in the present invention will be described.
Examples of the PVA-based resin (A) used in the present invention include unmodified PVA and modified PVA-based resin.

The average saponification degree of the PVA-based resin (A) used in the present invention is preferably 80 mol% or more, particularly 82 to 99.9 mol%, further 85 to 98.5 mol%, particularly. It is preferably 90 to 97 mol%. When unmodified PVA is used as the PVA-based resin (A), the average saponification degree is preferably 80 mol% or more, particularly 82 to 99 mol%, and further 85 to 90 mol. It is preferably%. When a modified PVA-based resin is used as the PVA-based resin (A), the average saponification degree is preferably 80 mol% or more, particularly 85 to 99.9 mol%, and further 90. It is preferably ~ 98 mol%. Further, when an anionic group-modified PVA-based resin is used as the PVA-based resin (A), the average saponification degree is preferably 85 mol% or more, particularly 88 to 99 mol%, and further. It is preferably 90 to 97 mol%. If the average saponification degree is too small, the solubility of the water-soluble film in water tends to decrease over time depending on the pH of the drug to be packaged. If the average saponification degree is too large, the solubility in water tends to be significantly reduced due to the heat history during film formation.

The degree of polymerization of the PVA-based resin (A) can generally be indicated by a water-soluble viscosity, and the viscosity of a 4 wt% aqueous solution at 20 ° C. is preferably 5 to 50 mPa · s, more preferably 10 to 45 mPa · s. s, particularly preferably 15 to 40 mPa · s. When unmodified PVA is used as the PVA-based resin (A), the viscosity of the 4 wt% aqueous solution of the unmodified PVA at 20 ° C. is preferably 5 to 50 mPa · s, more preferably 10 to 45 mPa · s. s, particularly preferably 15 to 40 mPa · s. When a modified PVA-based resin is used as the PVA-based resin (A), the viscosity of the modified PVA-based resin at 20 ° C. in a 4% by weight aqueous solution is preferably 5 to 50 mPa · s, more preferably 10 to 50 mPa · s. It is preferably 45 mPa · s, particularly preferably 15 to 40 mPa · s. If the viscosity is too small, the mechanical strength of the water-soluble film as a packaging material tends to decrease, while if it is too large, the viscosity of the aqueous solution during film formation tends to be high and the productivity tends to decrease.

The average saponification degree is measured according to JIS K 6726 3.5, and the viscosity of the 4 wt% aqueous solution is measured according to JIS K 6726 3.11.2.

Examples of the modified PVA-based resin used in the present invention include anionic group-modified PVA-based resin, cationic group-modified PVA, and nonionic group-modified PVA-based resin. Above all, it is preferable to use an anionic group-modified PVA-based resin in terms of solubility in water. Examples of the type of anionic group include a carboxyl group, a sulfonic acid group, and a phosphoric acid group, but a carboxyl group, a sulfonic acid group, and particularly a carboxyl group are preferable in terms of chemical resistance and stability over time. ..

In the present invention, the amount of modification of the anionic group-modified PVA resin is preferably 1 to 10 mol%, more preferably 2 to 9 mol%, particularly preferably 2 to 8 mol%, and particularly preferably. It is 3 to 7 mol%. If the amount of such modification is too small, the solubility in water tends to decrease, and if it is too large, the productivity of the PVA-based resin tends to decrease, the biodegradability tends to decrease, and blocking is caused. It tends to be easier and less practical.

In the present invention, the above-mentioned PVA-based resin (A) may be used in combination of two or more kinds having different saponification degree, viscosity, modified species, modified amount and the like. In the present invention, the PVA-based resin (A) is one containing A anion group-modified PVA-based resin and unmodified PVA.

The content ratio (weight ratio) of the modified PVA resin and the unmodified PVA is preferably 95/5 to 60/40, particularly 94/6 to 70/30, and further 93/7 to 80/20. Is preferable. If the content is too small, the plasticizer tends to bleed out, and if it is too large, blocking tends to occur.

When the modified PVA resin and the unmodified PVA are used in combination, the unmodified PVA preferably has a viscosity of a 4 wt% aqueous solution at 20 ° C. of 5 to 50 mPa · s, more preferably 8 to 45 mPa · s. In particular, it is preferably 12 to 40 mPa · s, and particularly preferably 15 to 35 mPa · s. If the viscosity is too small, the mechanical strength of the water-soluble film as a packaging material tends to decrease, while if it is too large, the viscosity of the aqueous solution during film formation tends to be high and the productivity tends to decrease.

Next, the water-soluble film of the present invention is produced, for example, as follows.

Unmodified PVA can be produced by saponifying a vinyl ester-based polymer obtained by polymerizing a vinyl ester-based compound.

Examples of such vinyl ester compounds include vinyl formate, vinyl acetate, trifluoroacetate, vinyl propionate, vinyl butyrate, vinyl caprate, vinyl laurate, vinyl versatic acid, vinyl palmitate, vinyl stearate and the like. Can be mentioned. Above all, it is preferable to use vinyl acetate as the vinyl ester compound. The vinyl ester compound may be used alone or in combination of two or more.

The modified PVA resin includes a method of copolymerizing the vinyl ester compound with an unsaturated monomer copolymerizable with the vinyl ester compound and then saponifying the resin, a method of post-modifying unmodified PVA, and the like. Can be manufactured by

In the present invention, the following unsaturated monomer copolymerizable with the vinyl ester compound may be copolymerized, but when a modified PVA resin is obtained, a modifying group is used as the following monomer. It is necessary to copolymerize the unsaturated monomer having. Examples of the unsaturated monomer include olefins such as ethylene, propylene, isobutylene, α-octene, α-dodecene, and α-octadecene, 3-butene-1-ol, 4-pentene-1-ol, and 5-. Hydroxy group-containing α-olefins such as hexen-1-ol and derivatives such as allyls thereof, unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, maleic anhydride, itaconic acid, and undecylene acid, and the like. Examples thereof include salts, monoesters, amides such as dialkyl esters, diacetone acrylamides, acrylamides and methacrylic amides, olefin sulfonic acids such as ethylene sulfonic acids, allyl sulfonic acids and metaallyl sulfonic acids, or salts thereof. These can be used alone or in combination of two or more. The content ratio of the copolymerizable monomer is usually 10 mol% or less.

Further, as the modified PVA-based resin, those having a primary hydroxyl group in the side chain, for example, those in which the number of primary hydroxyl groups is usually 1 to 5, preferably 1 to 2, particularly preferably 1 are also mentioned. Be done. In particular, it is preferable to have a secondary hydroxyl group in addition to the primary hydroxyl group, and examples thereof include a PVA-based resin having a 1,2-diol structural unit in the side chain and a PVA-based resin having a hydroxyalkyl group in the side chain. The PVA-based resin having a 1,2-diol structural unit in such a side chain is, for example, (i) a method for saponifying a copolymer of vinyl acetate and 3,4-diacetoxy-1-butene, (ii) acetic acid. Methods for saponifying and decarbonizing a copolymer of vinyl and vinyl ethylene carbonate, (iii) saponifying and decarbonizing a copolymer of vinyl acetate and 2,2-dialkyl-4-vinyl-1,3-dioxolane. It can be produced by a method of ketalization, (iv) a method of saponifying a copolymer of vinyl acetate and glycerin monoallyl ether, or the like.

As the polymerization method in the preparation of the PVA-based resin (A), for example, a known polymerization method such as a solution polymerization method, an emulsion polymerization method, or a suspension polymerization method can be arbitrarily used, but usually methanol, ethanol or isopropyl can be used. It is carried out by a solution polymerization method using a lower alcohol such as alcohol as a solvent. In the case of a modified PVA-based resin, as a method for charging a monomer in such solution polymerization, first, the entire amount of the vinyl ester-based compound and, for example, a part of the unsaturated monomer having a carboxyl group are charged and polymerized. Any method can be used, such as a method of starting and adding the remaining unsaturated monomer continuously or in a divided manner during the polymerization period, a method of collectively charging the unsaturated monomer having a carboxyl group, and the like. it can.

As the polymerization catalyst, a known polymerization catalyst such as an azo catalyst such as azobisisobutyronitrile, a peroxide catalyst such as acetyl peroxide, benzoyl peroxide, or lauroyl peroxide is appropriately selected depending on the polymerization method. be able to. The reaction temperature of the polymerization is selected from the range of 50 ° C. to the boiling point of the polymerization catalyst.

The saponification is carried out in the presence of a saponification catalyst by dissolving the obtained copolymer in alcohol. Examples of the alcohol include alcohols having 1 to 5 carbon atoms such as methanol, ethanol and butanol. These can be used alone or in combination of two or more. The concentration of the copolymer in alcohol is selected from the range of 20 to 50% by weight.

As the saponification catalyst, for example, an alkali metal hydroxide such as sodium hydroxide, potassium hydroxide, sodium methylate, sodium ethylate, potassium methylate, or an alkali catalyst such as alcoholate can be used, and an acid can be used. It is also possible to use a catalyst. The amount of the saponification catalyst used is preferably 1 to 100 mmol equivalent with respect to the vinyl ester compound. These saponification catalysts can be used alone or in combination of two or more.

The carboxyl group-modified PVA-based resin in the modified PVA-based resin can be produced by any method. For example, (I) an unsaturated monomer having a carboxyl group and a vinyl ester-based compound are copolymerized and then saponified. (II) A method of polymerizing a vinyl ester compound by coexisting alcohol, aldehyde, thiol or the like having a carboxyl group as a chain transfer agent, and then saponifying the compound.

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

Examples of the unsaturated monomer having a carboxyl group in the method (I) above include ethylenically unsaturated dicarboxylic acid (maleic acid, fumaric acid, itaconic acid, etc.) or ethylenically unsaturated dicarboxylic acid monoester (malein). Acid monoalkyl ester, fumaric acid monoalkyl ester, itaconic acid monoalkyl ester, etc.) or ethylenically unsaturated dicarboxylic acid diester (maleic acid dialkyl ester, fumaric acid dialkyl ester, itaconic acid dialkyl ester, etc.) [However, these diesters Needs to be converted to a carboxyl group by hydrolysis during the saponification of the copolymer. ], Or monomers such as ethylenically unsaturated carboxylic acid anhydrides (maleic anhydride, itaconic anhydride, etc.), or ethylenically unsaturated monocarboxylic acids ((meth) acrylic acid, crotonic acid, etc.), and theirs. Examples thereof include maleic acid, maleic acid monoalkyl ester, maleic acid dialkyl ester, maleate, maleic anhydride, itaconic acid, itaconic acid monoalkyl ester, itaconic acid dialkyl ester, (meth) acrylic acid and the like. It is preferable to use maleic acid, maleic acid monoalkyl ester, maleic acid dialkyl ester, maleate, maleic anhydride, and particularly maleic acid monoalkyl ester. These can be used alone or in combination of two or more.

In the above method (II), a compound derived from a thiol having a particularly large chain transfer effect is particularly effective, and examples thereof include compounds represented by the following general formulas (1) to (3).

In addition, salts of the compounds represented by the above general formulas (1) to (3) can also be mentioned. Specific examples thereof include mercaptoacetate, 2-mercaptopropionate, 3-mercaptopropionate, 2-mercaptostearate and the like. These compounds can be used alone or in combination of two or more.

The method for producing the above-mentioned carboxyl group-modified PVA-based resin is not limited to the above-mentioned method, and for example, the PVA-based resin (partially saponified or completely saponified) is reactive with hydroxyl groups such as dicarboxylic acid, aldehyde carboxylic acid, and hydroxycarboxylic acid. It is also possible to carry out a method of post-reacting a carboxyl group-containing compound having a certain functional group.

When a sulfonic acid-modified PVA-based resin modified with a sulfonic acid group is used, for example, vinyl sulfonic acid, styrene sulfonic acid, allyl sulfonic acid, metaallyl sulfonic acid, 2-acrylamide-2-methylpropane sulfonic acid, etc. A method of copolymerizing a copolymerized component of sulfonic acid or a salt thereof with a vinyl ester compound and then saponifying the sulfonic acid, vinyl sulfonic acid or a salt thereof, 2-acrylamide-2-methylpropanesulfonic acid or a salt thereof, and the like with PVA. It can be manufactured by a method of adding Michael to a based resin or the like.

On the other hand, examples of the method for post-modifying the unmodified PVA include a method for acetoacetic esterification, acetalization, urethanization, etherification, grafting, phosphoric acid esterification, and oxyalkyleneization of the unmodified PVA.

In addition to the unsaturated monomer having a carboxyl group and the vinyl ester compound, other general monomers may be contained within a range that does not impair the water solubility, and the polymerization may be carried out. Examples of the body include an alkyl ester of an ethylenically unsaturated carboxylic acid, an allyl ester of a saturated carboxylic acid, an α-olefin, an alkyl vinyl ether, an alkyl allyl ether, and other (meth) acrylamide, (meth) acrylonitrile, styrene, and vinyl chloride. Etc. can be used. These can be used alone or in combination of two or more.

In the present invention, it is preferable to include the plasticizer (B) in the PVA-based resin (A) from the viewpoint of giving flexibility to the water-soluble film when it is used as a drug package. It is important not to use only one type of plasticizer (B), but to use at least two types in combination.

One of the plasticizers (B) is a polyhydric alcohol (b1) having a melting point of 80 ° C. or higher (hereinafter, may be abbreviated as a plasticizer (b1)), and the other has a melting point of 80 ° C. or higher. It is a polyhydric alcohol (b2) having a temperature of 50 ° C. or lower (hereinafter, may be abbreviated as a plasticizer (b2)).

As the polyhydric alcohol (b1) having a melting point of 80 ° C. or higher, most of sugar alcohols, monosaccharides and polysaccharides can be applied. Among them, for example, salicyl alcohol (83 ° C.) and catechol (105 ° C.). ), Resolsinol (110 ° C.), Hydroquinone (172 ° C.), Bisphenol A (158 ° C.), Bisphenol F (162 ° C.), Neopentyl glycol (127 ° C.) and other dihydric alcohols, Fluoroglucinol (218 ° C.), etc. Trihydric alcohols, erythritol (121 ° C), treitol (88 ° C), tetrahydric alcohols such as pentaerythritol (260 ° C), xylitol (92 ° C), arabitol (103 ° C), fusitol (153 ° C), glucose (146 ° C). ° C), pentahydric alcohols such as fructose (104 ° C), hexahydric alcohols such as mannitol (166 ° C), sorbitol (95 ° C), inositol (225 ° C), lactitol (146 ° C), sucrose (186 ° C), trehalose. Examples thereof include octahydric alcohols such as (97 ° C.) and 9 or higher hydration alcohols such as Martitol (145 ° C.). These can be used alone or in combination of two or more. The numbers in parentheses above indicate the melting points of each compound.
Among the above, those having a melting point of 85 ° C. or higher, particularly preferably 90 ° C. or higher, are preferable in terms of the tensile strength of the water-soluble film. The upper limit of the melting point is preferably 300 ° C., particularly preferably 200 ° C.

Further, in the present invention, it is preferable that the number of hydroxyl groups in one molecule of the plasticizer (b1) is 4 or more in terms of compatibility with the PVA-based resin, and more preferably 5 to 10 is particularly preferable. The number is 6 to 8, and specifically, for example, sorbitol, sucrose, trehalose and the like are preferable.

Further, in the present invention, the plasticizer (b1) preferably has a molecular weight of 150 or more, more preferably 160 to 500, particularly 180 to 400, in terms of tension of the water-soluble film. Specifically, for example, sorbitol, sucrose and the like are preferable.

On the other hand, as the polyhydric alcohol (b2) having a melting point of 50 ° C. or lower, most aliphatic alcohols can be applied, and for example, ethylene glycol (-13 ° C.), diethylene glycol (-11 ° C.), and the like are preferable. Triethylene glycol (-7 ° C), propylene glycol (-59 ° C), tetraethylene glycol (-5.6 ° C), 1,3-propanediol (-27 ° C), 1,4-butanediol (20 ° C) , 1,6-hexanediol (40 ° C), tripropylene glycol, dihydric alcohols such as polyethylene glycol with a molecular weight of 2000 or less, trihydric or higher such as glycerin (18 ° C), diglycerin, triethanolamine (21 ° C). Alcohol can be mentioned. From the viewpoint of flexibility of the water-soluble film, a film having a melting point of 30 ° C. or lower, particularly preferably 20 ° C. or lower is preferable. The lower limit of the melting point is usually −80 ° C., preferably −10 ° C., and particularly preferably 0 ° C. These can be used alone or in combination of two or more. The numbers in parentheses above indicate the melting points of each compound.

Further, in the present invention, it is easy to control the flexibility in the vicinity of room temperature (25 ° C.) when the number of hydroxyl groups in one molecule of the plasticizer (b2) is 4 or less, particularly 3 or less. Preferably, specifically, for example, glycerin and the like are suitable.

Further, in the present invention, the plasticizer (b2) preferably has a molecular weight of 100 or less, more preferably 50 to 100, and particularly preferably 60 to 95, from the viewpoint of easy control of flexibility. Specifically, for example, glycerin and the like are suitable.

In the present invention, a plasticizer (b3) other than the above-mentioned plasticizers (b1) and (b2) can be used in combination, and examples of the plasticizer (b3) include trimethyl propane (58 ° C.) and diethylene glycol. Alcohols such as monomethyl ether, cyclohexanol, carbitol, polypropylene glycol, ethers such as dibutyl ether,
Carboxylic acids such as stearic acid, oleic acid, linoleic acid, linolenic acid, sorbic acid, citric acid, adipic acid, ketones such as cyclohexanone, amines such as monoethanolamine, triethanolamine, ethylenediamine, imidazole compounds, alanine, Examples thereof include amino acids such as glycine, aspartic acid, glutamic acid, histidine, lysine, and cysteine. These can be used alone or in combination of two or more.

In the present invention, the content of the plasticizer (B), to the PVA-based resin (A) 100 parts by weight of, Ri Ah at 25 to 50 wt parts, especially 27 to 50 parts by weight, more 30-50 wt Parts, particularly preferably 35 to 50 parts by weight. If the content of the plasticizer (B) is too small, the tension of the water-soluble film tends to be impaired over time when a liquid such as a liquid detergent is packaged into a package. If it is too much, the mechanical strength tends to decrease.

Regarding the above-mentioned plasticizer (b1) and plasticizer (b2), the content ratio (b1 / b2) thereof is preferably 0.5 to 5 by weight, particularly 0.5 to 4.5, and further. It is preferably 0.5 to 4, particularly 0.7 to 3. If the content is too small, the water-soluble film tends to be too soft and blocking tends to occur, and if it is too large, the water-soluble film tends to be too hard and brittle even in a low-humidity environment. ..

The contents of the plasticizer (b1) and the plasticizer (b2) are 5 to 40 parts by weight, and further 8 to 40 parts by weight, based on 100 parts by weight of the PVA-based resin (A). It is preferably 30 parts by weight, particularly preferably 10 to 25 parts by weight, and the plasticizer (b2) is preferably 5 to 40 parts by weight, more preferably 10 to 35 parts by weight, and particularly preferably 15 to 30 parts by weight.
If the amount of the plasticizer (b1) is too small, the water-soluble film tends to be too soft and blocking tends to occur, and if it is too large, the water-soluble film tends to be too hard and tends to become brittle even in a low humidity environment. is there. Further, if the amount of the plasticizer (b2) is too small, the water-soluble film tends to be too hard and tends to be brittle even in a low humidity environment, and if it is too large, the water-soluble film tends to be too soft and blocking is likely to occur. There is.

Further, the total amount of the plasticizer (b1) and the plasticizer (b2) is preferably 70% by weight or more, more preferably 80% by weight or more, and particularly 87% by weight or more, based on the entire plasticizer (B). In particular, it is preferably 90% by weight or more, more preferably 95% by weight or more. Particularly preferably, the entire plasticizer (B) is composed of only the plasticizer (b1) and the plasticizer (b2). If the total amount of the plasticizers (b1) and (b2) is too small, the mechanical strength tends to decrease.

In the present invention, a filler (C), a surfactant (D) and the like can be further contained, if necessary.

The filler (C) used in the present invention is contained for the purpose of blocking resistance, and specific examples thereof include inorganic fillers and organic fillers, with which organic fillers are preferable. The average particle size is preferably 0.1 to 20 μm, more preferably 0.5 to 15 μm. The average particle size can be measured by, for example, a laser diffraction type particle size distribution measuring device or the like.

The average particle size of the inorganic filler is preferably 1 to 10 μm, and if the average particle size is too small, the effect of dispersing the water-soluble film in water tends to be small, and if it is too large. When the water-soluble film is molded and stretched, it tends to become pinholes or deteriorate in appearance.

Specific examples of the inorganic filler include talc, clay, silicon dioxide, diatomaceous soil, kaolin, mica, asbestos, gypsum, graphite, glass balloon, glass beads, calcium sulfate, barium sulfate, ammonium sulfate, calcium sulfite, calcium carbonate. , Whisker-like calcium carbonate, magnesium carbonate, dosonite, dolomite, potassium titanate, carbon black, glass fiber, alumina fiber, boron fiber, processed mineral fiber, carbon fiber, carbon hollow sphere, 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 , Potassium chromate, calcium citrate and the like. These can be used alone or in combination of two or more.

The organic filler preferably has an average particle size of 0.5 to 20 μm, more preferably 0.5 to 10 μm, particularly preferably 0.5 to 7 μm, still more preferably 0.5 to 5 μm. is there. If the average particle size is too small, the cost tends to be high, and if it is too large, pinholes tend to occur when the water-soluble film is stretched during molding.

Examples of such an organic filler include starch, melamine-based resin, polymethyl (meth) acrylate-based resin, polystyrene-based resin, and biodegradable resin such as polylactic acid. As the organic filler, a biodegradable resin such as a polymethyl (meth) acrylate resin, a polystyrene resin, or a starch is preferably used. These can be used alone or in combination of two or more.

Examples of the above-mentioned starch include raw starch (corn starch, horse bell starch, sweet potato starch, wheat starch, kissaba starch, sago starch, tapioca starch, morokoshi starch, rice starch, bean starch, kudzu starch, warabi starch, hass starch, etc. Hishi starch, etc.), physically modified starch (α-starch, fractionated amylose, moist heat-treated starch, etc.), enzyme-modified starch (hydrolyzed dextrin, enzymatically degraded dextrin, amylose, etc.), chemically degraded modified starch (acid-treated starch, hypoa) Chloric acid oxidized starch, dialdehyde starch, etc.), chemically modified starch derivatives (esterified starch, etherified starch, cationized starch, crosslinked starch, etc.) and the like can be mentioned. Among them, it is preferable to use raw starch, especially corn starch and rice starch, from the viewpoint of easy availability and economy. These can be used alone or in combination of two or more.

The content of the filler (C) is preferably 1 to 30 parts by weight, more preferably 2 to 25 parts by weight, particularly 2.5 to 20 parts by weight, based on 100 parts by weight of the PVA-based resin (A). It is preferably a part. If the content is too small, the blocking resistance tends to decrease, and if it is too large, pinholes tend to occur when the water-soluble film is stretched during molding.

The surfactant (D) used in the present invention is contained for the purpose of improving the peelability from the cast surface during the production of a water-soluble film, and is usually a nonionic surfactant, a cationic surfactant, or an anion. Surfactants can be mentioned. Examples of the nonionic surfactant include polyoxyethylene nonylphenyl ether, polyoxyethylene octyl nonyl ether, polyoxyethylene dodecylphenyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene sorbitan monolaurate, and polyoxyethylene sorbitan mono. Polyoxyethylene such as palmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate, polyoxyalkylene alkyl ether phosphate monoethanolamine salt, polyoxyethylene lauryl amino ether, polyoxyethylene stearyl amino ether, etc. Examples thereof include alkyl amino ethers, which are used alone or in combination of two or more. Among them, polyoxyalkylene alkyl ether phosphoric acid ester monoethanolamine salt and polyoxyethylene lauryl amino ether are preferable from the viewpoint of production stability. These can be used alone or in combination of two or more.

The content of the surfactant (D) is preferably 0.01 to 3 parts by weight, more preferably 0.1 to 2.5 parts by weight, based on 100 parts by weight of the PVA-based resin (A). In particular, it is preferably 0.5 to 2 parts by weight. If the content is too small, the peelability between the cast surface of the film-forming device and the water-soluble film formed tends to decrease, and the productivity tends to decrease. If the content is too large, the water-soluble film is used as a packaging material. There is a tendency to cause inconveniences such as a decrease in adhesive strength at the time of sealing.

In the present invention, other water-soluble polymers (for example, sodium polyacrylate, polyethylene oxide, polyvinylpyrrolidone, dextrin, chitosan, chitin, methylcellulose, hydroxyethylcellulose, etc.) and other water-soluble polymers are used as long as the object of the invention is not impaired. , Fragrance, rust preventive, colorant, bulking agent, defoaming agent, ultraviolet absorber, liquid paraffin, fluorescent whitening agent, bitterness component (for example, denatonium benzoate, etc.) and the like can be contained. These can be used alone or in combination of two or more.

Further, in the present invention, it is preferable to add an antioxidant from the viewpoint of suppressing yellowing. Examples of such antioxidants include sulfites such as sodium sulfite, potassium sulfite, calcium sulfite, and ammonium sulfite, tartrate acid, ascorbic acid, sodium thiosulfate, catechol, and longalit, among which sulfites, particularly sodium sulfite. Is preferable. The blending amount is preferably 0.1 to 10 parts by weight, more preferably 0.2 to 5 parts by weight, and particularly preferably 0.3 to 3 parts by weight with respect to 100 parts by weight of the PVA-based resin (A).

In the present invention, as described above, a resin composition comprising a PVA-based resin (A) and a plasticizer (B), and if necessary, a filler (C), a surfactant (D), and the like is obtained. , Such a resin composition is dissolved or dispersed with water to prepare a film-forming raw material, and the film is formed to obtain a PVA-based film. For such film formation, for example, a melt extrusion method or a casting method can be adopted, and the casting method is preferable in terms of film thickness accuracy.

In the present invention, when the casting method is performed, for example, it is performed as follows.
As the dissolution method, normal temperature dissolution, high temperature dissolution, pressure dissolution and the like are usually adopted, and among them, high temperature dissolution and pressure dissolution are preferable because there are few undissolved substances and the productivity is excellent.
The melting temperature is usually 80 to 100 ° C., preferably 90 to 100 ° C. in the case of high temperature melting, and usually 80 to 130 ° C., preferably 90 to 120 ° C. in the case of pressure melting.
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 substances tend to remain, and if the dissolution time is too long, productivity tends to decrease.

Further, in the melting step, examples of the stirring blade include paddles, full zones, max blends, twisters, anchors, ribbons, propellers and the like.
Further, after dissolution, a defoaming treatment is performed on the obtained PVA-based resin aqueous solution, and examples of such defoaming methods include static defoaming, vacuum defoaming, biaxial extrusion defoaming and the like. Be done. Of these, static defoaming and biaxial extrusion defoaming are preferable.
The temperature for static defoaming is usually 50 to 100 ° C., preferably 70 to 95 ° C., and the defoaming time is usually 2 to 30 hours, preferably 5 to 20 hours.

In the casting method, for example, water is added to the PVA-based resin (A) (powder) to make a PVA-based resin aqueous solution, and the plasticizer (B) and other formulations are further added to prepare an aqueous dispersion of the resin composition or. Obtain an aqueous solution. Alternatively, water is added to the resin composition containing the PVA-based resin (A), the plasticizer (B), and various formulations to obtain an aqueous dispersion or aqueous solution of the resin composition. The solid content concentration of the aqueous dispersion or aqueous solution of the resin composition is preferably 10 to 50% by weight, particularly preferably 15 to 40% by weight, and further preferably 20 to 35% by weight. If the concentration is too low, the productivity of the water-soluble film tends to decrease, and if it is too high, the viscosity becomes too high, it takes time to defoam the dope, and die lines are generated during the formation of the water-soluble film. Tend to do. Further, if the temperature of the metal surface of the endless belt or drum roll is too low, it tends to take a long time to dry, and if it is too high, it tends to foam during film formation.

The above aqueous dispersion or aqueous solution is passed through a slit such as a T-die and poured onto a cast surface such as a metal surface of an endless belt or drum roll or a plastic base material surface such as a polyethylene terephthalate film, dried, and if necessary. Further heat treatment can be performed to obtain the PVA-based film of the present invention.
For example, it can be carried out under the following film forming conditions.

The temperature of the discharge portion of the PVA-based resin composition in the aqueous dispersion or aqueous solution is preferably 60 to 98 ° C, particularly 70 to 95 ° C. If the temperature is too low, the drying time tends to be long and the productivity tends to decrease, and if it is too high, foaming or the like tends to occur.

At the time of film formation, the film formation speed is preferably 3 to 80 m / min, particularly preferably 5 to 60 m / min, and further preferably 8 to 50 m / min.
Further, the heat treatment can be performed by a thermal roll, but other examples include floating and far-infrared ray treatment. In particular, it is preferable to use a heat roll in terms of productivity. The heat treatment temperature is preferably 50 to 150 ° C., particularly preferably 70 to 130 ° C., and the heat treatment time is preferably 1 to 60 seconds, particularly 3 to 50 seconds, and further. Is preferably 5 to 40 seconds.

Alternatively, an applicator can be used to cast an aqueous dispersion or aqueous solution of the resin composition onto a plastic base material such as a polyethylene terephthalate film or a polyethylene film or a metal base material and dry it to obtain a PVA-based film.

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

The width of the PVA-based film is appropriately selected depending on the intended use and the like, but is preferably 300 to 5000 mm, more preferably 500 to 4000 mm, and particularly preferably 800 to 3000 mm. If the width is too narrow, the production efficiency tends to decrease, and if it is too wide, it tends to be difficult to control the slack and the film thickness.

The length of the PVA-based film is appropriately selected depending on the intended use and the like, but is preferably 500 to 20000 m, more preferably 800 to 15000 m, and particularly preferably 1000 to 10000 m. If the length is too short, it tends to take time and effort to switch the film, and if it is too long, the appearance tends to be poor due to winding tightening and the weight tends to be too heavy.

The surface of the PVA-based film may be plain, but from the viewpoints of blocking resistance, slipperiness during processing, reduction of adhesion between products, and appearance, an embossed pattern is formed on one or both sides of the PVA-based film. It is also preferable to perform uneven processing such as pear-skin pattern, special engraving pattern, etc.
In such uneven processing, the processing temperature is usually 60 to 150 ° C., preferably 80 to 140 ° C. The processing pressure is usually 2 to 8 MPa, preferably 3 to 7 MPa. The processing time depends on the processing pressure and the film forming speed, but is usually 0.01 to 5 seconds, preferably 0.1 to 3 seconds.
Further, if necessary, a cooling treatment may be performed after the uneven processing treatment in order to prevent unintended stretching of the film due to heat.

Further, in the present invention, the water content of the obtained PVA-based film (water-soluble film) is preferably 3 to 15% by weight, particularly 5 to 14% by weight, in terms of mechanical strength and sealing property. Further, it is preferably 6 to 13% by weight. If the water content is too low, the film tends to be too hard, and if it is too high, blocking tends to occur. The adjustment to such a water content can be achieved by appropriately setting drying conditions and humidity control conditions.
The water content is measured in accordance with JIS K 6726 3.4, and the obtained volatile matter value is used as the water content.

In the present invention, the film formation is preferably carried out in an environment of, for example, 10 to 35 ° C, particularly 15 to 30 ° C. Humidity is usually 70% RH or less.

In the present invention, the obtained PVA-based film can be wound into a core tube (S1) to form a film roll. The obtained film roll can be supplied as a product as it is, but preferably, it is wound around a core tube (S2) having a length corresponding to a film width of a desired size and supplied as a film roll.

The core tube (S1) for winding the film has a cylindrical shape, and the material thereof can be appropriately selected from metal, plastic and the like, but metal is preferable in terms of robustness and strength.
The inner diameter of the core tube (S1) is preferably 3 to 30 cm, more preferably 10 to 20 cm.
The wall thickness of the core tube (S1) is preferably 1 to 30 mm, more preferably 2 to 25 mm.
The length of the core tube (S1) needs to be longer than the width of the film, and it is preferable that the length of the core tube (S1) protrudes from the end of the film roll by 1 to 50 cm.

The core tube (S2) has a cylindrical shape, and the material thereof can be appropriately selected from paper, metal, plastic, etc., but paper is preferable in terms of weight reduction and handling.
The inner diameter of the core tube (S2) is preferably 3 to 30 cm, more preferably 10 to 20 cm.
The wall thickness of the core tube (S2) is preferably 1 to 30 mm, more preferably 3 to 25 mm.
The length of the core tube (S2) may be as long as or longer than the width of the PVA-based film of the product, and is preferably the same to 50 cm longer.

When wound around the core tube (S2), the PVA-based film is slit to a desired width.
Such a slit is slit by using a shear blade, a leather blade, or the like, but it is preferable to slit by a shear blade from the viewpoint of smoothness of the slit cross section.

In the present invention, the obtained film roll but is to wrap in packaging film vapor barrier resin is not particularly restricted but includes such films, moisture permeability according to ^{10g / m 2 · 24hr (JIS} Z 0208 Measurement) The following can be used. Specific examples include, for example, a single-layer film such as high-density polyethylene, low-density polyethylene, polypropylene, polyester, polyvinylidene chloride-coated polypropylene, glass-deposited polyester, or a laminated film thereof, or with a split cloth, paper, or non-woven fabric. Laminated film and the like can be mentioned. Examples of the laminated film include a laminated film of glass-deposited polyester and polyethylene, a laminated film of polyvinylidene chloride-coated polypropylene and polyethylene, and the like.

It is preferable that such a film is subjected to antistatic treatment from the viewpoint of preventing foreign matter from being mixed in, and the antistatic agent may be kneaded into the film or coated on the surface. In the case of kneading, an antistatic agent of about 0.01 to 5% by weight is used with respect to the resin, and in the case of surface coating, ^{an antistatic agent of about 0.01 to 1 g / m 2 is used.}
As the antistatic agent, for example, alkyldiethanolamine, polyoxyethylenealkylamine, higher fatty acid alkanolamide, sorbitan fatty acid ester and the like are used.

Next, it is preferable to wrap the film roll with a wrapping film of a steam barrier resin, and then further wrap a wrapping film made of an aluminum material. Such a film includes an aluminum foil, an aluminum foil, and a moisture-resistant plastic film. Laminated film (for example, laminated film of aluminum foil and polyethylene film), laminated film of aluminum vapor-deposited film and moisture-resistant plastic film (for example, laminated film of aluminum-deposited polyester film and polyethylene film), laminated film of alumina-deposited film and moisture-resistant plastic film (For example, a laminated film of an alumina vapor-deposited polyester film and a polyethylene film) and the like. In the present invention, a laminated film of an aluminum foil and a polyolefin film and a laminated film of an aluminum vapor-deposited film and a polyolefin film are particularly useful, and in particular, a stretched polypropylene film. / Polyethylene film / Aluminum foil / Laminated film composed of polyethylene film, Stretched polypropylene film / Low density polyethylene film / Laminated film composed of aluminum foil, etc. are useful.
For packaging, the inner wrapping film made of water vapor barrier resin and the outer wrapping film made of aluminum material may be sequentially wrapped, and the excess portion in the width direction may be pushed into the core tube.

In the film roll of the present invention, in order to prevent scratches on the edges and adhesion of foreign substances such as dust, core tube through holes are provided at both ends of the film roll directly on the film roll or after being wrapped with a wrapping film. A protective pad can be attached.
As for the shape of the protective pad, a disk-shaped sheet or film is practical according to the film roll. In order to make the protective effect remarkable, it is preferable to add a buffer function such as a foam, a woven fabric, or a non-woven fabric. Further, a desiccant may be separately enclosed in order to protect the film roll from moisture, or may be laminated or mixed in the protective pad.
Plastic is advantageous as the material of the protective pad, and specific examples thereof include polystyrene, polyethylene, polypropylene, polyester, and polyvinyl chloride.

Further, as the protective pad containing the desiccant, for example, calcium chloride, silica gel, molecular sieves, saccharides, particularly saccharides having high osmotic pressure, desiccants such as water-absorbent resins, or water-absorbing agents are used as natural celluloses, synthetic celluloses, etc. A moisture-absorbing layer that is dispersed, impregnated, coated and dried in a moldable material such as glass cloth or non-woven fabric, or these desiccants or water-absorbents are applied to the above-mentioned moldable materials, polyester films, polyethylene films, polypropylene films, Teflon ( Registered trademark) Examples thereof include those sandwiched between thermoplastic resin films such as films.
Examples of commercially available sheet-shaped desiccants include "ID Sheet" manufactured by IDI, "Arrow Sheet" and "Zeo Sheet" manufactured by Shinagawa Kasei Co., Ltd., and "High Sheet Dry" manufactured by High Sheet Industry Co., Ltd. ..

The film roll packaged by such means is supported by providing brackets (support plates) on the projecting portions at both ends of the core tube or placing the projecting portions at both ends on a pedestal, and is supported in the so-called air without touching the ground. It is preferable that the film is stored and transported in a floating state. Brackets are used when the film width is relatively small, and mounts are used when the film width is relatively large.
The bracket is made of plywood or a plastic plate, and its size may be such that the four sides of the bracket are larger than the diameter of the film roll.

Then, a pair of brackets are arranged and fitted upright on the core tube protrusions at both ends of the film roll so as to face each other, and are provided on the film roll. The fitting may be provided with a hollow hole slightly larger than the diameter of the core tube in the central portion of the bracket, or may be hollowed out in a U shape from the upper portion to the central portion of the bracket so that the core tube can be easily inserted.

Film rolls supported by brackets are stored and transported in cartons such as cardboard boxes, but when using rectangular brackets, the four corners should be cut off to facilitate storage work. preferable.
Further, it is advantageous to fix the pair of brackets with a binding tape so that they do not wobble, and the side surface (thickness portion) of the brackets has the same width as the tape so that the tape does not move or loosen at that time. It is also practical to provide a tape misalignment prevention groove to some extent.

When storing or transporting the packaged film roll, it is desirable to avoid extremely high and low temperature, low humidity and high humidity conditions, specifically, the temperature is 10 to 30 ° C and the humidity is 40 to 75% RH. ..

The water-soluble film of the present invention thus obtained is useful for various packaging applications, and above all, it is useful for unit packaging applications such as chemicals. The drug is not particularly limited and may be alkaline, neutral or acidic, and the shape of the drug may be any of granules, tablets, powders, powders, liquids and the like, but particularly in water. Drugs that are dissolved or dispersed are preferred, and are particularly useful for packaging liquid detergents.

As the liquid detergent, the pH value when dissolved or dispersed in water is preferably 6 to 12, particularly preferably 7 to 11, and the water content is preferably 15% by weight or less, particularly 0. It is preferably 1 to 10% by weight, more preferably 0.1 to 7% by weight, and the film does not gel or insolubilize and has excellent water solubility.
The pH value is measured in accordance with JIS K 3362 8.3. The water content is measured according to JIS K 3362 7.21.3.

<Drug packaging>
The drug package of the present invention comprises a liquid detergent encapsulated in a package made of a water-soluble film. The size of the drug package is usually 10 to 50 mm in length, preferably 20 to 40 mm. The thickness of the film of the package made of the water-soluble film is usually 10 to 120 μm, preferably 15 to 110 μm, and more preferably 20 to 100 μm. The amount of liquid detergent contained is usually 5 to 50 mL, preferably 10 to 40 mL.

The surface of the drug package of the present invention is usually smooth. However, from the viewpoint of blocking resistance, slipperiness during processing, reduction of adhesion between products (packages), and appearance, embossed pattern, fine uneven pattern, special engraving pattern on the outer surface of the package (water-soluble film). , Etc. may be subjected to uneven processing. Further, the drug package of the present invention in which the liquid detergent is packaged retains the shape containing the liquid detergent during storage. Then, during use (during washing), the package (water-soluble film) comes into contact with water, so that the package dissolves and the contained liquid detergent flows out of the package.

A known method can be adopted when packaging a liquid detergent into a package using the water-soluble film of the present invention. For example, (1) a method of heat-sealing, (2) a method of water-sealing, (3) a method of glue-sealing, and the like can be mentioned. Among them, the (2) water-sealing method is versatile and advantageous.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded.
In the example, "part" and "%" mean the weight standard.

The following PVA resins were prepared.
Carboxyl-modified PVA (A1): 4% aqueous solution viscosity at 20 ° C. 22 mPa · s, average saponification degree 96 mol%, modification amount by maleic acid monomethyl ester 4.0 mol%
Carboxyl-modified PVA (A2): Viscosity of 4% aqueous solution at 20 ° C. 22 mPa · s, average saponification degree 94 mol%, modification amount with maleic acid monomethyl ester 2.0 mol%
Unmodified PVA (A3): 4% aqueous solution viscosity at 20 ° C., 18 mPa · s, average saponification degree 88 mol%

The following plasticizers were prepared.
・ Sorbitol (b1)
・ Glycerin (b2)
-Trimethylolpropane (b3)

< Reference example 1>
As PVA-based resin (A), 100 parts of carboxyl group-modified PVA (A1), 20 parts of sorbitol (b1) and 20 parts of glycerin (b2) as plasticizer (B), and starch (average) as filler (C). 8 parts of particle size (20 μm), 2 parts of polyoxyalkylene alkyl ether phosphoric acid ester monoethanolamine salt as surfactant (D) and water were mixed and dissolved, and a PVA aqueous solution in which starch was dispersed (PVA aqueous solution). Solid content concentration 25%) was obtained.
The obtained PVA aqueous solution was defoamed at 80 ° C. and cooled to 40 ° C. The PVA aqueous solution was cast on a polyethylene terephthalate film, passed through a 3 m drying chamber (105 ° C.) at a speed of 0.350 m / min, and dried to obtain a 94 μm-thick PVA-based film (water-soluble film). Obtained.
The PVA-based film obtained above was evaluated as follows. The evaluation results are shown in Table 1.

[Tensile strength, tensile elongation]
Using the obtained PVA-based film, the measurement was performed in accordance with JIS K 7127 (1999). That is, after leaving the PVA film under the conditions of 23 ° C. and 50% RH humidity control for 24 hours before the measurement, the PVA-based film was subjected to Autograph AGS-H manufactured by Shimadzu Corporation (the analysis software was Factory manufactured by Shimadzu Corporation). Using SHKiBU2000), the measurement was performed at a tensile speed of 200 mm / min (film width 15 mm, chuck distance 50 mm).

[Evaluation of PVA-based film tension on drug packaging]
With respect to the PVA-based film obtained above, a drug package was prepared by the following procedure using a package manufacturing machine manufactured by Angel.
That is, a PVA-based film (bottom film) is fixed on a mold (molded package: length 45 mm, width 42 mm, height 30 mm) at the bottom of the device, and a PVA-based film (top) is also fixed at the top of the device. The film) was fixed. The bottom film was heated for 10 seconds with a dryer that generates hot air at 90 ° C., and the bottom film was vacuum formed into a mold. After that, 20 mL of liquid detergent (containing 5.4% glycerin, 22.6% propylene glycol, 10.4% water) packaged in "Ariel Power Gel Ball" manufactured by P & G was put into a molded PVA film. did. 1.5 g of water was applied to the top film, and the top film and the bottom film were pressure-bonded. After crimping for 30 seconds, the vacuum was released to obtain a drug package. Then, after adjusting the humidity in an environment of 23 ° C. and 40% RH for 2 hours, the height (X1 mm) of the drug package when it was naturally self-supporting was measured and found to be 30 mm.
Subsequently, after the drug package was prepared, it was left in an environment of 40 ° C. and 65% RH for 1 week, then left in an environment of 23 ° C. and 50% RH for 1 hour, and then naturally self-sustaining. The height (X2 mm) of the drug package was measured, and the tension of the PVA-based film of the drug package was evaluated by the value (X3 mm) calculated by the following formula. The smaller the value of X3, the better the tension of the PVA-based film.
(Formula) X3 = X1-X2

<Examples 1 to 4 , Reference Examples 2 and 3 , Comparative Examples 1 to 3>
In Reference Example 1, a PVA-based film (water-soluble film) was obtained in the same manner except that the changes were made as shown in Table 1.
The obtained PVA-based film (water-soluble film) was evaluated in the same manner as in Reference Example 1.

The evaluation results of Examples , Comparative Examples and Reference Examples are shown in Table 1 below.

From the results in Table 1 above, the water-soluble film of the example in which the plasticizer has a specific composition has excellent mechanical properties such as high tensile strength and high tensile elongation of the water-soluble film, and further, a liquid such as a liquid detergent can be used. It can be seen that the water-soluble film can form a good package without impairing the tension of the water-soluble film over time even in the packaged state. On the other hand, in Comparative Example 1 containing no sorbitol, the tension of the water-soluble film was lost and the tensile elongation was low, and in Comparative Example 2 in which the amount of the plasticizer itself was too small, the tensile elongation was also high. In addition, the tension of the water-soluble film is a little weak and the tensile elongation is low in Comparative Example 3 in which only sorbitol is used as a plasticizer. In addition, bleed-out is also seen, and it can be seen that the object of the present invention has not been achieved in either case.

The water-soluble film of the present invention has excellent water solubility, and also has excellent mechanical properties such as high tensile strength and high tensile elongation of the water-soluble film. In particular, a package containing a liquid such as a liquid detergent is used. It is a water-soluble film that can form a good package without damaging the tension of the water-soluble film over time even in a state, and can be used for various packaging applications, and is particularly useful for unit packaging applications such as chemicals. Is.

Claims (9)

A water-soluble film containing a polyvinyl alcohol-based resin (A) and a plasticizer (B), wherein the polyvinyl alcohol-based resin (A) contains an anionic group-modified polyvinyl alcohol-based resin and unmodified polyvinyl alcohol. The plasticizer (B) contains a polyhydric alcohol (b1) having a melting point of 80 ° C. or higher and a polyvalent alcohol (b2) having a melting point of 50 ° C. or lower, and the content of the plasticizer (B) is high. Polyvinyl alcohol resin (A) is 25 to 50 parts by weight with respect to 100 parts by weight, and the polyhydric alcohol (b1) having a melting point of 80 ° C. or higher and the polyhydric alcohol (b2) having a melting point of 50 ° C. or lower are A water-soluble film having a content ratio (b1 / b2) of 0.5 to 5 by weight. The water-soluble film according to claim 1, wherein the polyhydric alcohol (b1) having a melting point of 80 ° C. or higher has four or more hydroxyl groups in one molecule. The water-soluble film according to claim 1 or 2, wherein the polyhydric alcohol (b1) having a melting point of 80 ° C. or higher has a molecular weight of 150 or higher. The water-soluble film according to any one of claims 1 to 3, wherein the polyhydric alcohol (b2) having a melting point of 50 ° C. or less has 4 or less hydroxyl groups in one molecule. The water-soluble film according to any one of claims 1 to 4, wherein the polyhydric alcohol (b2) having a melting point of 50 ° C. or lower has a molecular weight of 100 or less. The water-soluble film according to any one of claims 1 to 5 , wherein the water-soluble film has a water content of 3 to 15% by weight. The water-soluble film according to any one of claims 1 to 6 , which is used for drug packaging. A drug package comprising the liquid detergent packaged in the water-soluble film according to any one of claims 1 to 7. The drug package according to claim 8 , wherein the liquid detergent has a pH value of 6 to 12 and a water content of 15% by weight or less when dissolved or dispersed in water.