WO2020031969A1 - Water-soluble film for packaging, and package - Google Patents

Abstract

This water-soluble film for packaging contains a polyvinyl alcohol, a plasticizer and a water surface diffusion agent; the polyvinyl alcohol contains a modified polyvinyl alcohol; the content of the plasticizer is 3 parts by mass or more but less than 10 parts by mass relative to 100 parts by mass of the polyvinyl alcohol; and the content of the water surface diffusion agent is from 0.1 part by mass to 15 parts by mass (inclusive) relative to 100 parts by mass of the polyvinyl alcohol.

Description

Water-soluble packaging film and package

The present invention relates to a water-soluble packaging film made of a polyvinyl alcohol film and a package formed from the water-soluble packaging film.

2. Description of the Related Art A package is widely known in which various chemicals such as pesticides and detergents are sealed in a water-soluble film in unit amounts and packaged. When this package is put into water in its packaging form at the time of use, the water-soluble film dissolves and the contents can be dissolved or dispersed in water. For example, if a pesticide such as jumbo for paddy fields is used in this package, the water-soluble film surrounding it dissolves after being put into the paddy field, and the contained pesticides such as jumbo will float on the water surface. By dispersing throughout the paddy field, the pesticidal active ingredient will spread throughout the paddy field.

Patent Literature 1 discloses that a water-soluble film suitable for packaging agricultural chemicals such as jumbo agents contains polyvinyl alcohol (PVA), a water surface diffusing agent, and a plasticizer, and the content of the plasticizer is 100 parts by mass of PVA. Disclosed is a PVA film having 10 to 40 parts by mass. It has been shown that this PVA film contains a water surface diffusing agent and contains a predetermined amount of a plasticizer, whereby the diffusivity of the drug when put into a paddy field becomes excellent.
Patent Document 2 discloses an agricultural chemical packaging film formed by forming a sulfonic acid group-modified polyvinyl alcohol containing 0.1 to 20 mol% of a sulfonic acid group-containing unit.

WO2015 / 118978 JP-A-7-118407

By the way, agricultural chemicals for paddy fields such as jumbo agents are often used in hot and humid areas, and processing for sealing and packaging the chemicals using a water-soluble film is sometimes performed under hot and humid conditions. However, when a process of forming a package using the PVA film described in Patent Document 1 is performed under high temperature and high humidity, the PVA film absorbs moisture over time and softens, so that the film adheres to a processing machine. May occur.
Further, the agricultural chemical packaging film disclosed in Patent Literature 2 does not have excellent diffusion properties of the chemical when put into a paddy field.

Therefore, the present invention has a problem in that when a package formed of a water-soluble packaging film is put into water such as a paddy field, the encapsulated drug has excellent diffusibility and is processed under high temperature and high humidity. It is an object of the present invention to provide a water-soluble packaging film that is less likely to cause the problem.

The present inventors have assiduously studied and found that the above problem can be solved by using a modified PVA as a PVA in a water-soluble packaging film and adding a predetermined amount of a water surface diffusing agent and a plasticizer. The present invention has been completed. That is, the present invention provides the following [1] to [10].
[1] A water-soluble packaging film containing polyvinyl alcohol, a plasticizer, and a water surface diffusing agent,
The polyvinyl alcohol contains a modified polyvinyl alcohol,
Water-soluble packaging wherein the content of the plasticizer is 3 parts by mass or more and less than 10 parts by mass and the content of the water surface diffusing agent is 0.1 part by mass or more and 15 parts by mass or less with respect to 100 parts by mass of the polyvinyl alcohol. For film.
[2] The water-soluble packaging film according to the above [1], wherein the modified polyvinyl alcohol is at least one selected from the group consisting of a pyrrolidone ring group-modified polyvinyl alcohol and a sulfonic acid group-modified polyvinyl alcohol.
[3] The water-soluble packaging film according to the above [2], wherein the modified polyvinyl alcohol is a sulfonic acid group-modified polyvinyl alcohol.
[4] The water-soluble packaging film according to any one of [1] to [3], wherein the polyvinyl alcohol further contains unmodified polyvinyl alcohol.
[5] The content of the modified polyvinyl alcohol is 30% by mass or more and 90% by mass or less based on the total amount of polyvinyl alcohol, and the content of the unmodified polyvinyl alcohol is 10% by mass or more and 70% by mass or less. The water-soluble packaging film according to the above [4].
[6] The water-soluble packaging film according to any one of the above [1] to [5], wherein the water surface diffusing agent is a dialkyl sulfosuccinate.
[7] The water-soluble packaging film according to any one of [1] to [6], wherein the film surface has an uneven shape having a height difference of 10 μm or more and 200 μm or less.
[8] The water-soluble packaging film according to any one of the above [1] to [7], which is for agricultural chemical packaging.
[9] A package comprising the water-soluble packaging film according to any one of [1] to [8] above, and a drug contained in the water-soluble packaging film.
[10] The package according to the above [9], wherein the drug is an agricultural chemical.

According to the present invention, when a package formed by a water-soluble packaging film is put into water such as a paddy field, the diffusion property of the encapsulated drug is improved, and even when processed under high temperature and high humidity, there is a problem. It is possible to provide a water-soluble packaging film which is less likely to cause the problem.

It is a typical side view of the water-soluble packaging film concerning one embodiment of the present invention. FIG. 4 is a schematic side view of a water-soluble packaging film according to another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in more detail.
[Water-soluble packaging film]
The water-soluble packaging film of the present invention contains polyvinyl alcohol, a plasticizer, and a water surface diffusing agent. Hereinafter, each component will be described in more detail.

(Polyvinyl alcohol)
The water-soluble packaging film of the present invention contains polyvinyl alcohol (hereinafter, also referred to as “PVA”). PVA is obtained by polymerizing a monomer containing a vinyl ester to obtain a polymer according to a conventionally known method, and then saponifying the polymer, that is, hydrolyzing the polymer. In general, an alkali or an acid is used for saponification, but it is preferable to use an alkali. As PVA, only one kind may be used, or two or more kinds may be used in combination.

Examples of vinyl esters include vinyl acetate, vinyl formate, vinyl propionate, vinyl butyrate, vinyl pivalate, vinyl versatate, vinyl laurate, vinyl stearate, and vinyl benzoate. The polymerization method of the vinyl ester is not particularly limited, and examples thereof include a solution polymerization method, a bulk polymerization method, and a suspension polymerization method.

ＰＶ The PVA in the present invention contains at least a modified polyvinyl alcohol (modified PVA). In the present invention, when a modified PVA is used as the PVA, and a plasticizer and a water surface diffusing agent are contained in predetermined amounts, as described later, when the package formed by the water-soluble packaging film is put into water. In addition, the diffusion property of the encapsulated drug becomes excellent. Furthermore, since the softening of the film under high temperature and high humidity is suppressed, stickiness is reduced, and troubles hardly occur during film processing. Therefore, the bag making property when forming the package from the water-soluble packaging film using the processing machine is improved.

変 性 The content of the modified PVA with respect to the total amount of PVA is preferably 30% by mass or more and 100% by mass or less. By setting the content of the modified PVA to 30% by mass or more, it becomes easy to improve the diffusibility of the above-mentioned drug. Further, the content of the modified PVA is preferably 90% by mass or less. The content of the modified PVA is more preferably from 60% by mass to 90% by mass, and still more preferably from 65% by mass to 80% by mass. When the content of the modified PVA is equal to or more than the lower limit, the diffusibility of the drug can be further improved. In addition, when the content is not less than the upper limit, unmodified PVA or the like described later can be contained in a predetermined amount or more.

The PVA preferably contains unmodified polyvinyl alcohol (unmodified PVA) in addition to the modified PVA. Unmodified PVA is obtained by saponifying polyvinyl ester. When the PVA further contains unmodified PVA, softening of the film under high temperature and high humidity is suppressed, and troubles during processing and the like are less likely to occur.
The content of unmodified PVA is preferably 70% by mass or less based on the total amount of PVA. When the content is 70% by mass or less, the content of the above-mentioned modified PVA can be increased. Further, the content of the unmodified PVA is preferably 10% by mass or more. When the content of the unmodified PVA is 10% by mass or more, the softening of the film under high temperature and high humidity is suppressed, and the processability and the like are easily improved.
The content of the unmodified PVA is more preferably from 10% by mass to 40% by mass, and still more preferably from 20% by mass to 35% by mass. By keeping the content of the unmodified PVA within these ranges, the softening of the film under high temperature and high humidity is effectively suppressed while maintaining the above-mentioned excellent diffusibility of the drug, and the processability and the like are easily improved. Become.

<Modified PVA>
Hereinafter, the modified PVA will be described in more detail. The modified PVA has structural units other than the structural units derived from polyvinyl ester. More specifically, the modified PVA is obtained by saponifying a polymer of a vinyl ester and another unsaturated monomer. Other unsaturated monomers include monomers other than vinyl esters, such as monomers having a carbon-carbon double bond such as a vinyl group.
Specifically, olefins, (meth) acrylic acid and salts thereof, (meth) acrylic acid esters, unsaturated acids other than (meth) acrylic acid, salts and esters thereof, (meth) acrylamides, N-vinylamides , Vinyl ethers, nitriles, vinyl halides, allyl compounds, vinyl silyl compounds, isopropenyl acetate, sulfonic acid group-containing compounds, amino group-containing compounds and the like.

Examples of the olefin include ethylene, propylene, 1-butene, and isobutene. Examples of the (meth) acrylate include alkyl (meth) acrylates having 1 to 10, preferably 1 to 2, carbon atoms in the alkyl group. Specific examples of the alkyl (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, i-propyl (meth) acrylate, and (meth) acrylic acid. n-butyl and 2-ethylhexyl (meth) acrylate.
Unsaturated acids other than (meth) acrylic acid, salts and esters thereof include maleic acid and its salts, maleic acid esters, itaconic acid and its salts, itaconic acid esters, methylenemalonic acid and its salts, and methylenemalonic acid esters Is mentioned.
(Meth) acrylamides include acrylamide, n-methylacrylamide, N-ethylacrylamide, N, N-dimethylacrylamide and the like. Examples of N-vinyl amides include N-vinyl pyrrolidone. Examples of vinyl ethers include methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, i-propyl vinyl ether, and n-butyl vinyl ether.

Examples of the nitriles include (meth) acrylonitrile. Examples of vinyl halides include vinyl chloride and vinylidene chloride. Allyl compounds include allyl acetate and allyl chloride. Examples of the vinylsilyl compound include vinyltrimethoxysilane.
Examples of the sulfonic acid group-containing compound include (meth) acrylamidoalkanesulfonic acid such as (meth) acrylamidopropanesulfonic acid and salts thereof, and olefinsulfonic acids such as ethylenesulfonic acid, allylsulfonic acid, and methallylsulfonic acid, and salts thereof. No.
Examples of the amino group-containing compound include allylamine, polyoxyethylene allylamine, polyoxypropylene allylamine, polyoxyethylene vinylamine, and polyoxypropylene vinylamine.

変 性 Further, the modified PVA may be a PVA obtained by adding a carboxyl group, a sulfonic acid group, or a pyrrolidone ring group to PVA by graft polymerization or the like.

As the modified PVA, PVA modified with at least one functional group selected from a sulfonic acid group, a pyrrolidone ring group, and a carboxyl group, or PVA modified with a (meth) acrylate ester is preferable. The functional groups include salts of these functional groups such as sodium and potassium, in addition to these functional groups.
Therefore, in the modified PVA, (meth) acrylic acid, other unsaturated acids and salts thereof, (meth) acrylate, N-vinylpyrrolidone, and a compound containing a sulfonic acid group are used as monomers other than the vinyl ester. Is preferred. Further, those in which the above functional groups are added by graft polymerization or the like are also preferable.
These may be used alone or in combination of two or more.

Among the above, PVA modified with at least one functional group selected from a sulfonic acid group, a pyrrolidone ring group, and a carboxyl group is more preferable. The modified PVA modified by these functional groups has excellent chemical resistance. Therefore, the water-soluble packaging film has excellent solubility even after being in contact with a drug or the like for a long time by using the modified PVA modified with the above functional group.
Further, as the modified PVA, from the viewpoint of chemical resistance, PVA modified with at least one kind of functional group selected from a sulfonic acid group and a pyrrolidone ring group is more preferable, and the effect of the present invention is easily exerted. Particularly preferred is PVA modified with sulfonic acid groups.

As described above, specific examples of suitable modified PVA include sulfonic acid group-modified PVA, pyrrolidone ring group-modified PVA, carboxyl group-modified PVA, and saponified product of a copolymer of acrylic acid ester and vinyl ester. Among these, at least one selected from sulfonic acid group-modified PVA and pyrrolidone ring group-modified PVA is more preferred, and sulfonic acid group-modified PVA is even more preferred.
When the modified PVA is a sulfonic acid group-modified PVA, the water solubility at low temperatures can be increased. When the modified PVA is a pyrrolidone ring group-modified PVA, the discoloration resistance of the film can be increased.

The sulfonic acid group-modified PVA may be one in which a sulfonic acid group is introduced by modification, and is preferably one in which a sulfonic acid group is bonded to a polymer main chain via a linking group. Examples of the linking group include an amide group, an alkylene group, an ester group, and an ether group. Of these, a combination of an amide group and an alkylene group is preferred. In order to make the linking group a combination of an amide group and an alkylene group, the above-mentioned (meth) acrylamidoalkanesulfonic acid or a salt thereof may be used as an unsaturated monomer.
Further, the sulfonic acid group is preferably composed of a sulfonic acid salt, particularly preferably a sodium sulfonic acid group. When the modified PVA is sodium sulfonate-modified PVA, the sodium sulfonate-modified PVA preferably has a structural unit represented by the following formula (1).

(In the formula (1), R ¹ represents an alkylene group having 1 to 4 carbon atoms.)

The pyrrolidone ring group-modified PVA is not particularly limited as long as the pyrrolidone ring is introduced by modification, but preferably has a structural unit represented by the following formula (2). In order to obtain a pyrrolidone ring group-modified PVA having such a constitutional unit, for example, N-vinylpyrrolidone may be used as another unsaturated monomer.

The carboxyl group-modified PVA is not particularly limited as long as it has a carboxyl group introduced by modification, but the structure represented by the following formula (3-1), (3-2) or (3-3) It preferably has units.

(In the above formulas (3-1), (3-2) and (3-3), X ¹ , X ² , X ³ , X ⁴ and X ⁵ each independently represent a hydrogen atom, a metal atom or a methyl group. That is, the carboxyl group in this specification includes salts and methyl esters of the carboxyl group. Examples of the metal atom include a sodium atom, etc. In the above formula (3-2), R ³ is Represents an alkylene group having 1 to 10 carbon atoms.)

The modified PVA has a modification amount of, for example, 0.1 mol% or more and 20 mol% or less. Therefore, the modified PVA modified with at least one functional group selected from the above-mentioned sulfonic acid group, pyrrolidone ring group, and carboxyl group has a molar ratio of these functional groups to the total number of moles of the constituent units of the modified PVA. The number is from 0.1 mol% to 20 mol%. In a saponified product of a copolymer of an acrylate ester and a vinyl ester, the content of the acrylate-derived structural unit is from 0.1 mol% to 20 mol%, based on the total moles of the structural units of the modified PVA.

The sulfonic acid group-modified amount of the sulfonic acid group-modified PVA is preferably from 0.1 mol% to 6 mol%, more preferably from 1 mol% to 5 mol%, from the viewpoint of improving chemical resistance and water solubility. is there. From the same viewpoint, the pyrrolidone ring group-modified amount of the pyrrolidone ring group-modified PVA is preferably from 0.1 mol% to 20 mol%, more preferably from 0.5 mol% to 10 mol%, and still more preferably. 1 mol% or more and 8 mol% or less, still more preferably 1.5 mol% or more and 6 mol% or less, particularly preferably 2 mol% or more and 5 mol% or less.

In the present invention, as described above, it is particularly preferable that the PVA contains a sulfonic acid group-modified PVA, but the content of the sulfonic acid group-modified PVA is preferably 30% by mass or more based on the total amount of PVA. It is 100% by mass or less, more preferably 60% by mass or more and 90% by mass or less, and further preferably 65% by mass or more and 80% by mass or less. When the water-soluble packaging film contains the sulfonic acid group-modified PVA in a predetermined amount or more, the chemical resistance, the water solubility, and the diffusibility of the drug are more excellent. Further, when the content is not more than the above upper limit, stickiness of the film under high temperature and high humidity can be suppressed, and processability can be easily improved.

The saponification degree of PVA is preferably 80 mol% or more and 99.9 mol% or less. When the saponification degree is in such a range, the water solubility required for the water-soluble packaging film can be easily secured.
Further, the suitable range of the degree of saponification of PVA also differs depending on the presence or absence of modification and the type of modifying group. For example, the unmodified PVA is preferably at least 80 mol% and at most 99.9 mol% as described above, but from the viewpoint of further improving the water solubility, more preferably at least 80 mol% and at most 95 mol%, and at least 85 mol% It is more preferably at most 92 mol%.
On the other hand, for example, the degree of saponification of modified PVA such as pyrrolidone ring group-modified PVA and sulfonic acid group-modified PVA is preferably 80 mol% or more and 99.9 mol% or less, as described above. From the viewpoint of improving a good balance, 85 mol% or more and 99 mol% or less are more preferable, and 90 mol% or more and 98 mol% or less are further preferable.
The saponification degree is measured according to JIS K6726. The saponification degree indicates the ratio of units actually saponified into vinyl alcohol units among units converted into vinyl alcohol units by saponification.
The method for adjusting the saponification degree is not particularly limited. The saponification degree can be appropriately adjusted by saponification conditions, that is, hydrolysis conditions.

重合 The degree of polymerization of PVA is not particularly limited, but is preferably 400 or more, more preferably 700 or more, and further preferably 900 or more. Further, it is preferably 2000 or less, more preferably 1800 or less, and further preferably 1500 or less. When the polymerization degree is equal to or more than the lower limit and equal to or less than the upper limit, the viscosity of the aqueous PVA solution can be made appropriate when the water-soluble packaging film is formed, and the water solubility of PVA is easily improved. . Further, the strength of the water-soluble packaging film can be easily improved. In addition, the said polymerization degree is measured based on JISK6726.

PVA, as a 4% by mass aqueous solution, has a viscosity measured at 20 ° C. of preferably 3 mPa · s or more, more preferably 8 mPa · s or more. The viscosity is preferably 30 mPa · s or less, more preferably 20 mPa · s or less. In addition, such a viscosity can be measured according to JISK6726.

水溶 The water-soluble packaging film is mainly composed of PVA. Specifically, the content of PVA is preferably 70% by mass or more, more preferably 75% by mass or more, and further preferably 80% by mass or more, based on the total amount of the water-soluble packaging film. Further, the content of PVA is preferably 98% by mass or less, more preferably 96% by mass or less, and further preferably 93% by mass or less. When the content of PVA is at least the lower limit, the water-soluble packaging film tends to have good water solubility. Further, when the amount is not more than the above upper limit, additives such as a water surface diffusing agent and a plasticizer can be appropriately compounded in the water-soluble packaging film.

(Plasticizer)
The water-soluble packaging film of the present invention further contains a plasticizer. Since the water-soluble packaging film contains a plasticizer, it has appropriate flexibility and improves water solubility. And, when used in combination with the water surface diffusing agent, the diffusing property of the above-mentioned agent becomes excellent. Further, the glass transition point is lowered, and the durability at low temperatures is improved.
The plasticizer is not particularly limited and includes, for example, polyhydric alcohols such as glycerin, diglycerin, diethylene glycol, trimethylolpropane, triethylene glycol, dipropylene glycol, propylene glycol, and glucose; and polyhydric alcohols such as polyethylene glycol and polypropylene glycol. Examples thereof include ethers, phenol derivatives such as bisphenol A and bisphenol S, amide compounds such as N-methylpyrrolidone, compounds in which ethylene oxide is added to polyhydric alcohols such as glycerin, pentaerythritol and sorbitol, and water. These may be used alone or in combination of two or more.
Among the above plasticizers, glycerin, diglycerin, trimethylolpropane, polyethylene glycol, polypropylene glycol, triethylene glycol, dipropylene glycol, and propylene glycol are preferred from the viewpoint of improving water solubility and drug diffusibility. As the plasticizer, diglycerin and trimethylolpropane are particularly preferable from the viewpoint of suppressing stickiness under high temperature and high humidity and improving workability. Diglycerin and trimethylolpropane may be used alone or in combination.

分子 The molecular weight of the plasticizer is preferably 90 or more, more preferably 120 or more, and further preferably 130 or more. When it is 90 or more, the water solubility and the diffusibility of the drug can be easily improved. Moreover, by setting it to 120 or more, it is easy to suppress stickiness under high temperature and high humidity and to improve workability. The molecular weight of the plasticizer is preferably 1200 or less, more preferably 1000 or less, and further preferably 500 or less.

(Water surface diffusion agent)
The water-soluble packaging film of the present invention further contains a water surface diffusing agent. The type of the water surface diffusing agent used in the present invention is not particularly limited, but a dialkyl sulfosuccinate is preferable in order to easily exert the effects of the present invention. The dialkyl sulfosuccinate is a compound having a structure in which two carboxyl groups in the sulfosuccinate are each converted to an alkyl ester, and may be obtained by any production method as long as it has the structure. .
The alkyl groups in the two alkyl ester moieties of the dialkyl sulfosuccinate may be the same or different, but are preferably the same in view of easy production.
In the dialkyl sulfosuccinate, one or both of the alkyl groups may be a linear alkyl group, or one or both of them may be a branched alkyl group. Examples of the alkyl group include methyl, ethyl, propyl, isopropyl, pentyl, hexyl, heptyl, octyl, 2-ethylhexyl, nonyl, decanyl, undecanyl, dodecanyl and the like. Those having 1 to 12 carbon atoms are exemplified.
It is preferable that one or both of the alkyl groups in the dialkyl sulfosuccinate is an alkyl group having 6 to 12 carbon atoms because the diffusibility of the drug contained in the water-soluble packaging film is further improved. It is more preferable that the alkyl group has 7 to 10 alkyl groups, and it is further preferable that both alkyl groups have the carbon number within the above range.
Examples of the salt in the dialkyl sulfosuccinate include an inorganic salt, preferably a sodium salt, a potassium salt, and an ammonium salt, and more preferably a sodium salt. As the dialkyl sulfosuccinate, sodium di (2-ethylhexyl) sulfosuccinate is particularly preferred. Also, sodium di (n-octyl) sulfosuccinate (sodium dioctyl sulfosuccinate) is particularly preferred. The water surface diffusing agent is different from the following surfactants, and in one embodiment of the present invention, the surfactant is other than dialkyl sulfosuccinate.

(Content of plasticizer and water surface diffusing agent)
In the water-soluble packaging film of the present invention, the content of the plasticizer is 3 parts by mass or more and less than 10 parts by mass with respect to 100 parts by mass of PVA, and the content of the water surface diffusing agent is 0.1 part by mass with respect to 100 parts by mass of PVA. It is 1 part by mass or more and 15 parts by mass or less. In the present invention, when the PVA contains the modified PVA as described above, and the plasticizer and the water surface diffusing agent are contained in these predetermined amounts, when the package formed from the water-soluble packaging film is put into water, The diffusibility of the drug to be used is excellent. Further, softening and stickiness under high temperature and high humidity are suppressed, and problems during processing are less likely to occur. Therefore, the bag making property when the package is formed from the water-soluble packaging film is improved.

On the other hand, when the content of the water surface diffusing agent is out of the above range, the diffusibility of the contained drug is not excellent, and when it exceeds 15 parts by mass, the content of the water surface diffusing agent is unnecessarily large. The mechanical strength of the water-soluble packaging film may be reduced.
In light of enhancing the diffusivity of the contained drug, the content of the water surface diffusing agent is preferably 0.9 parts by mass or more, and more preferably 2 parts by mass or more. The content of the water surface diffusing agent is preferably 9 parts by mass or less, more preferably 6 parts by mass or less, and more preferably 4.5 parts by mass or less, from the viewpoint of improving the mechanical strength while improving the diffusibility of the drug. More preferred. In the present invention, by using the above-mentioned modified PVA, even if the content of the water surface diffusing agent is relatively small, it is easy to make the diffusing property of the drug excellent.

In addition, when the content of the plasticizer in the water-soluble packaging film is less than 3 parts by mass, the water-soluble packaging film may not be rapidly decomposed in water and may not sufficiently improve the diffusibility of the contained drug. There is. On the other hand, when the content of the plasticizer is 10 parts by mass or more, for example, the water-soluble packaging film is softened under high temperature and high humidity, and when the film is processed, the film adheres to a processing machine, and the bag-forming property is improved. Workability, etc. may deteriorate. In the present invention, even when the content of the plasticizer is as small as less than 10 parts by mass, the use of the above-mentioned predetermined modified PVA can ensure excellent drug diffusibility and water solubility.
The content of the plasticizer is preferably 4 parts by mass or more, more preferably 5 parts by mass or more, preferably 9.8 parts by mass or less, and more preferably 7.5 parts by mass or less.

(Other additives)
The water-soluble packaging film of the present invention may further contain, if necessary, additives usually used for PVA films, such as fillers, surfactants, coloring agents, fragrances, defoamers, release agents, and ultraviolet absorbers. You may contain suitably.
Examples of the filler include inorganic particles. The inorganic particles are not particularly limited, but examples include silica, clay, kaolin, aluminum hydroxide, calcium carbonate, titanium dioxide, barium sulfate, satin white, talc, aluminum oxide, zirconia, and the like. Among them, silica is preferable from the viewpoint of blocking prevention. The content of the filler is preferably 0.01 to 5 parts by mass, more preferably 0.1 to 3 parts by mass, and still more preferably 0.2 to 2 parts by mass with respect to 100 parts by mass of polyvinyl alcohol.
As the surfactant, for example, a nonionic surfactant is preferable. Examples of the nonionic surfactant include an ether-based nonionic surfactant, an ester-based nonionic surfactant, and an ether / ester-based nonionic surfactant. Examples of the ether nonionic surfactant include polyoxyethylene alkylphenyl ether, polyoxyethylene alkylphenyl ether, and polyoxyethylene polyoxypropylene glycol.
Examples of the polyoxyethylene alkyl ether include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, and polyoxyethylene oleyl ether. Examples of the polyoxyethylene alkyl phenyl ether include polyoxyethylene octyl phenyl ether and polyoxyethylene nonyl phenyl ether.
Examples of the ester nonionic surfactant include polyoxyethylene-monolaurate, sorbitan fatty acid ester, pentaerythritol fatty acid partial ester, propylene glycol monofatty acid ester, glycerin monofatty acid ester, and polyoxyethylene fatty acid ester. . Examples of the polyoxyethylene fatty acid ester include polyoxyethylene monolaurate and polyoxyethylene dioleate.
Among them, polyoxyethylene polyoxypropylene glycol and polyoxyethylene monolaurate are preferred.
The content of the surfactant is preferably 0.01 to 3.0 parts by mass, more preferably 0.05 to 2.0 parts by mass, and still more preferably 0.1 to 1.0 part by mass with respect to 100 parts by mass of polyvinyl alcohol. 5 parts by mass.

(Uneven shape)
The water-soluble packaging film of the present invention preferably has an uneven shape. The uneven shape brings a height difference to the film surface. The uneven shape may be formed along either the film width direction or the longitudinal direction, but it is preferable that the uneven shape is formed on the entire film. Further, the shape of the unevenness is not particularly limited. For example, it is preferable that the unevenness has a corrugated shape in a cross section along the width direction (that is, the TD direction). The corrugated irregularities are preferably formed in a curved line as shown in FIG. 1, but may be corrugated irregularities having a rectangular cross section as shown in FIG. Is also good. The uneven shape may be formed by embossing or the like described later.
The pattern of the concavo-convex shape is not particularly limited, and examples thereof include a silk pattern, a satin pattern, a grain pattern, a hairline pattern, a hemp pattern, and a skin tone pattern.

A water-soluble packaging film having an uneven shape has a height difference H on the surface of the film. The height difference H is a difference between the maximum height of the adjacent convex portion 10 and the minimum height of the concave portion 11 on one surface as shown in FIGS.
It is preferable that the water-soluble packaging film of the present invention has a concavo-convex shape having a height difference H of 10 μm or more and 200 μm or less. When the height difference H of the uneven shape is 10 μm or more, the dissolution rate when the medicine-containing package is put into water can be increased, and the diffusivity of the medicine after dissolving the package can be easily improved. When the thickness is 200 μm or less, wrinkles and the like are hardly formed in the film by embossing, and the quality of the film is improved. From these viewpoints, it is more preferable that the height difference between the concave and convex shapes is 40 μm or more and 100 μm or less.

The water-soluble packaging film may be formed with irregularities at a pitch P on the film surface. The pitch P is a distance between the maximum height points (ie, vertices) of the adjacent convex portions 10 and 10. In the case where the concavo-convex shape has a rectangular cross-section as shown in FIG. 2 and a portion having a maximum height continues at a fixed length, the center position is defined as a maximum height point (apex).
The pitch P of the uneven shape is not particularly limited, but is, for example, 0.2 mm or more and 1.5 mm or less, preferably 0.3 mm or more and 1.0 mm or less, and more preferably 0.4 mm or more and 0.8 mm or less.
The height difference H may be equal over the entire film, or may be a combination of a plurality of irregularities having a height difference. The same applies to the pitch P. Note that the height difference H and the pitch P of the uneven shape may be within the above ranges on one surface of the film.

凹凸 The unevenness of the film is such that the height difference H is in the above-mentioned range, and a film having a large unevenness is sometimes called a deep emboss. However, the uneven shape is not limited to the deep emboss, and may be uneven having a height difference smaller than the above-described height difference. In such a case, for example, it is preferable that the film has a surface roughness (Ra) of 0.3 μm or more and 1 μm or less and a maximum height (Rz) of 3 μm or more and 9 μm or less.

(thickness)
The thickness T of the water-soluble packaging film of the present invention is, for example, 8 μm or more and 50 μm or less, preferably 10 μm or more and 35 μm or less, and more preferably 13 μm or more and 30 μm or less. When the thickness T of the film is 10 μm or more, the film strength is increased, and for example, wrinkles and tears are less likely to be formed in the embossed film, and the quality of the film is improved. When the thickness of the film is 35 μm or less, the dissolution rate when the package is put into water is increased.
Note that the height difference H, pitch P, and thickness T of the uneven shape may be measured using a stereo microscope, as described in Examples described later.

The water-soluble packaging film of the present invention is used for packaging various chemicals, for example, used for packaging various chemicals such as agricultural chemicals, industrial chemicals, dyes, detergents, fertilizers, cosmetics, sanitary products, and pharmaceuticals. Is done. Of these, pesticides are preferred. When the package formed from the water-soluble packaging film of the present invention is put into water, the medicine contained therein after the package is dissolved diffuses quickly and over a wide range. Therefore, the water-soluble packaging film of the present invention is more preferably used for agricultural chemicals in paddy fields.
The pesticide is preferably a water-dispersible or water-soluble preparation such as a paddy field herbicide (so-called jumbo preparation), a wettable powder, a granular wettable powder, and a water solvent. The pesticide is preferably a floating type that floats on the water surface after being sprayed, and a floating type herbicide for paddy fields (jumbo agent) is more preferable.
The properties of the drug are not particularly limited, and may be acidic, neutral, or alkaline. Examples of the form of the drug include a powder, a lump, a gel, a liquid and the like, and a powder or a lump is preferable from the viewpoint of excellent diffusibility of the drug. Although there is no particular limitation on the form of packaging, it is preferable to seal and package the drug in unit quantities.

[Package]
The present invention further provides a package. In the package of the present invention, the drug packaging film is used as a packaging material for packaging a drug. Specifically, the package of the present invention includes the above-described drug packaging film and a drug included in the drug packaging film. The drug is appropriately selected from those listed above, and is preferably a pesticide. In the package, the packaging material constituted by the medicine packaging film may be in a form that can encapsulate a medicine therein, and for example, may be a bag.

The method of using the packaging material as a bag is not particularly limited. For example, a bag may be formed by folding a single film and bonding the periphery thereof, or by laminating two films and bonding the periphery to form a bag. Or a bag in another way. The method for bonding the film is not particularly limited, and the film may be bonded by heat sealing, an adhesive, or the like, but heat sealing is preferable. The temperature of the heat sealing is not particularly limited, but is, for example, 70 ° C or more and 160 ° C or less, and preferably 80 ° C or more and 150 ° C or less.
In general, when heat sealing is performed, particularly when heat sealing is performed under high temperature and high humidity (for example, at 30 ° C. or higher and humidity is higher than 50%), a problem may occur in which a film adheres to a processing machine or the like and the heat sealing cannot be performed. The water-soluble packaging film of the present invention has a low stickiness even under high temperature and high humidity, does not easily cause problems during processing, and has good bag making properties. Further, the medicine packaging film constituting the bag may be appropriately shaped or the like.

[Production method of water-soluble packaging film]
The method for producing the water-soluble packaging film is not particularly limited. For example, PVA, a plasticizer, a water surface diffusing agent, and other additives that are added as necessary, a PVA aqueous solution obtained by diluting with water, A method of casting a film on a supporting member, drying the film, and forming a film is used. Further, the PVA aqueous solution may be cast after appropriately passing through a filter.
The method of casting the PVA aqueous solution on the support member includes a casting method, a roll coating method, a lip coating method, a spin coating method, a screen coating method, a fountain coating method, a dipping method, a spray method, and the like.

In the PVA aqueous solution, components other than water are diluted with water at a concentration of preferably 35% by mass or less, more preferably 25% by mass or less, and still more preferably 20% by mass or less based on the total amount of the aqueous solution. The components other than water are preferably diluted with water at a concentration of preferably 8% by mass or more, more preferably 10% by mass or more, and still more preferably 12% by mass or more.
When the concentration is within the above range, the viscosity of the PVA aqueous solution becomes appropriate and the casting of the PVA aqueous solution becomes easy. When the concentration is equal to or more than the lower limit, the drying time is shortened, and a water-soluble packaging film of good quality is easily obtained.

The support member may be any material that can maintain the PVA aqueous solution on the surface and support the obtained film when the PVA aqueous solution is cast. Examples of the material of the support member include polyolefin, polyester, and acrylic resin, but a support member made of a material other than these may be used. Further, the support member may be in the form of a sheet or a film, but may have another shape.
The drying after the casting of the PVA aqueous solution may be performed by any method, and examples thereof include a method of drying naturally and a method of heating and drying at a temperature equal to or lower than the glass transition temperature of PVA.

ＰＶ The formed PVA film is preferably peeled off from the support member and used as a water-soluble packaging film. Further, it is preferable to perform embossing on the formed PVA film. Embossing may be performed after the formed PVA film is peeled from the support member.

(Embossing)
The embossing is performed by passing a PVA film between the embossing roll and the backup roll. The embossing roll has an uneven shape on the roll surface. The uneven shape of the roll surface may be appropriately selected according to the uneven shape of the water-soluble packaging film. Therefore, it is preferable that the concavo-convex shape on the roll surface is formed on the entire film. Further, it is preferable that the cross section along the width direction has corrugated irregularities, like the film surface. The corrugations may be curved, but are preferably corrugations having a rectangular cross section. Even in the case of the embossing roll, even in the case of the corrugated irregularities having a rectangular cross section in the embossing roll (see FIG. 2), the corrugated rectangular corrugated irregularities were not formed in the film, and the film was formed in a curved line as shown in FIG. Often becomes wavy.
The pattern of the uneven shape on the roll surface is not particularly limited, and examples thereof include a silk pattern, a satin pattern, a grain pattern, a hairline pattern, a hemp pattern, and a leather pattern.

The height difference between the embossing rolls is preferably 100 μm or more and 350 μm or less, more preferably 150 μm or more and 300 μm or less. When the height difference is equal to or more than the lower limit, the height difference H of the uneven shape in the water-soluble packaging film is easily set to be equal to or more than the lower limit. On the other hand, when the height difference is less than or equal to the upper limit, the height difference H of the concavo-convex shape of the obtained film tends to be less than or equal to the upper limit.
In addition, on the surface of the embossing roll, the uneven shape may have a pitch equal to or close to the pitch P of the uneven shape formed on the film. Therefore, the pitch of the concavo-convex shape on the surface of the embossing roll is not particularly limited, for example, 0.2 mm or more and 1.5 mm or less, preferably 0.3 mm or more and 1.0 mm or less, more preferably 0.4 mm or more and 0.8 mm or less. is there.
Note that, similarly to the above-described height difference H and pitch P of the film, the height difference of the concavo-convex shape on the roll surface is the difference between the maximum height of the adjacent convex portion and the minimum height of the concave portion. Are the distances between the maximum height points, which can be measured by observing with a stereoscopic microscope in the same manner as the film surface.

However, the uneven shape of the surface of the emboss roll is not limited to the above, and may be uneven having a height difference smaller than the above-described height difference, or a so-called mat emboss roll. By forming the irregularities with the mat embossing roll, it becomes easy to adjust the surface roughness (Ra) and the maximum height (Rz) of the film surface within the above-mentioned predetermined ranges.

The backup roll used in embossing may be a roll used for general embossing, and for example, a wool paper roll or a rubber roll having a roll surface of rubber may be used. Although the hardness of the roll surface of the backup roll is not particularly limited, it is, for example, a hardness A of 60 to 95 °, preferably 70 to 95 °. The hardness A is a durometer hardness specified in JIS K6253-3.

At the time of embossing, the emboss roll may be heated at, for example, 50 to 150 ° C., preferably 80 to 120 ° C. On the other hand, the backup roll may be heated, but may be kept at around normal temperature (23 ° C.) without being heated. Specifically, the temperature of the backup roll may be, for example, about 5 to 50 ° C. The embossing roll may be pressed against the backup roll so that the pressing force (linear pressure) is, for example, 40 to 250 kg / cm, preferably 50 to 200 kg / cm.

Furthermore, the PVA film may be passed between the embossing roll and the backup roll at a speed of, for example, 1 to 50 m / min, preferably 5 to 20 m / min.

The embossing may be performed either in-line or off-line. In the case of in-line, after a PVA film is formed from a PVA solution, embossing is performed on the production line without winding.
On the other hand, in the case of off-line, a PVA film is formed from a PVA solution, and is once wound up into a roll, and then is reeled out again to perform embossing. In the off-line, the PVA film wound up in a roll shape may be wound up with the above-mentioned support member being superimposed, but even in such a case, before the embossing is performed after feeding, the PVA film is supported. It is good to peel off from the member.
In either case of in-line or off-line, the film is embossed and then wound into a roll, for example, and stored in a warehouse or the like as a roll.

で は In this production method, the PVA film may be stretched. Stretching may be performed before embossing, or may be performed after embossing. When performed before embossing, it may be performed during drying after casting, or may be performed after drying. Examples of the stretching method include a method using a roll, a method using a tenter, a method using a winding device, a method using drying shrinkage, and a method using a combination thereof. The stretching may be performed, for example, at a stretching ratio of about 1.05 to 3 times. The PVA film may be appropriately subjected to a known process such as an annealing process performed on the film.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

The evaluation method of the water-soluble packaging film is as follows.
[Film thickness T, height difference H of uneven shape, pitch P]
The surface of the water-soluble packaging film was observed with a stereoscopic microscope (“SE-1300” manufactured by SELMIC), and the thickness T, height difference H of the unevenness, and pitch P of the film were measured. The height difference H of the concavo-convex shape is the height difference between the adjacent convex portions and concave portions in the film width direction (TD direction), and the pitch P is the distance between vertices in the width direction.
The measurement conditions were as follows: After the obtained water-soluble packaging film was left for 24 hours in an environment of 23 ° C. and 50% RH, the film was cut with a feather razor along the TD direction of the film, and the film was cut in the MD direction. 5 points were measured in a cross section perpendicular to the vertical direction, and the average value in the observed region was defined as thickness T, height difference H, and pitch P.

[Surface roughness (Ra), maximum height (Rz)]
After leaving the obtained water-soluble packaging film in an environment of 23 ° C. and 50% RH for 4 hours, the measurement speed is 0.060 mm / sec, the measurement length is 4 mm, and the measurement range is ±± in the TD direction of the film. The surface roughness (Ra) and the maximum height (Rz) were measured three times according to JIS B0601-2001. The average values were defined as the surface roughness (Ra) and the maximum height (Rz), respectively.

[Diffusion test]
The diffusivity of the water-soluble packaging film was evaluated by the following method.
The obtained water-soluble packaging film was folded into two, and three ends were heat-sealed to produce a 5 cm × 4 cm bag with one end opened. 15 g of polyethylene pellets (“Petrocene 205” manufactured by Tosoh Corporation, pellet shape: cylinder, diameter 3 mm, length 5 mm) are put into the obtained bag, and the open end is heat-sealed, so that the package having the pellet inside is packed. I got
The film was sufficiently absorbed by leaving the obtained package in an environment of 23 ° C. × 50% RH for 24 hours. Thereafter, 1.5 L of pure water adjusted to a water temperature of 23 ° C. is put into a 37 cm × 30 cm × 45 mm deep bat, and the package containing the pellets is floated in the bat and the time required for the package to disintegrate, and that the pellets Was visually observed and evaluated according to the following criteria.
<Tear time>
The package broke in water in less than 1:30 seconds.
2: The package broke in water in 30 seconds or more and less than 60 seconds.
3: The package broke in water in 60 seconds or more and less than 100 seconds.
4: The package broke in water in 100 seconds or more.
<Diffusion>
1: The pellet spread almost all over the bat within 60 seconds after the package was broken.
2: After 60 seconds from the break of the package, the pellets did not spread over the whole but spread to about half the area of the bat.
4: After the package was torn, the pellets hardly spread.

[Chemical dissolution resistance test]
The solubility of the water-soluble packaging film was evaluated by the water solubility after the following chemical resistance test. The obtained water-soluble packaging film was folded into two, and three ends were heat-sealed to produce a 5 cm × 4 cm bag with one end opened. 10 g of "Mega Zeta Jumbo" manufactured by Sumitomo Chemical Co., Ltd. was put into the obtained bag, and the open end was heat-sealed to obtain a package having pyraclonyl / propylisulfuron granules inside.
After leaving the obtained package for 24 hours in an environment of 23 ° C. and 50% RH, the film was sufficiently absorbed by water and then sealed in a sealed container (trade name “PTFE inner cylinder sealed” manufactured by Sansho Co., Ltd.). Container with a metal valve for SR-50 "), and the sealed container was sealed so that water and a plasticizer would not scatter from the package. Then, after leaving for 4 months in an oven at a temperature of 54 ° C., the package was released and the inclusions were removed to obtain a film for evaluating chemical resistance.
The obtained film for chemical resistance evaluation was cut into a size of 30 mm × 30 mm, weighed, and fixed to a jig. Then, 500 ml of water was put into a 500 ml beaker, and the chemical resistance evaluation film fixed to the jig was placed in water while maintaining the water temperature at 23 ° C. while stirring with a stirrer so that the bottom of the swirl reached the 400 ml mark. It was immersed and evaluated according to the following criteria. The time when the film penetrated and was torn was defined as the torn time, and the time when the residue of the film became invisible was measured as the dissolution time.
<Tear time>
A: less than 15 seconds B: 15 seconds or more and less than 21 seconds C: 21 seconds or more <dissolution time>
A: Less than 45 seconds B: 45 seconds or more and less than 90 seconds C: 90 seconds or more

[Bag-making properties]
The obtained water-soluble packaging film having a width of 220 mm was vertically sealed with a vertical pillow-type automatic filling and packaging machine (“MC501” manufactured by Sanko Machine Co., Ltd.) in an environment of 30 ° C. and 60% RH. The workability at the time of bag making at 140 ° C. and a horizontal sealing temperature of 135 ° C. was evaluated according to the following criteria.
A: The bag was made B: The film adhered to the seal bar and the bag was not made [Chemical resistance solubility and discoloration resistance]
The obtained drug packaging film was folded into two, and three ends were heat-sealed to produce a 5 cm × 4 cm bag with one end opened. 25 g of trichloroisocyanuric acid powder was added to this bag, and the open end was heat-sealed to obtain a package having a powder of trichloroisocyanuric acid inside.
The obtained package was left in an environment of 40 ° C. and 90% RH for 24 hours to sufficiently absorb the film, and then sealed in a sealed container (trade name “PTFE inner cylinder sealed container SR” manufactured by Sansho Co., Ltd.). -50 with metal valve "), and sealed the sealed container to prevent water and plasticizer from splashing from the bag. After the sample was left in an oven at a temperature of 70 ° C. for one week, the package was opened to remove the inclusions, a film for evaluating chemical resistance was prepared, and the chemical resistance solubility and chemical visibility were evaluated.
(Chemical resistance solubility)
The obtained film for chemical resistance evaluation was cut into a size of 30 mm × 30 mm, weighed, and fixed to a jig. Then, 500 ml of water was put into a 500 ml beaker, and the evaluation film fixed to the jig was immersed in water while maintaining the water temperature at 23 ° C. while stirring with a stirrer so that the lower part of the spiral reached the mark of 400 ml. The resulting aqueous solution was left as it was for 60 minutes, and the obtained aqueous solution was filtered through a mesh having a mesh size of 300 μm whose weight was measured in advance to separate undissolved gel components. The mesh was dried at 80 ° C. for 3 hours, and the solubility (%) was calculated from the change in weight.
(Chemical discoloration resistance)
The YI of the obtained evaluation film was measured using a colorimeter (Model “ZE2000” manufactured by Nippon Denshoku Industries Co., Ltd.), and the measured YI value was used as the initial YI value. Further, the obtained evaluation film was left to stand in an environment of 80 ° C. for 3 days, and further left for 24 hours in an environment of 23 ° C. and 50% RH. Then, YI was measured to obtain a time-dependent YI value. . The degree of yellowing (ΔYI) was measured according to the following formula, and the chemical discoloration resistance was evaluated.
Yellowing degree (ΔYI) = YI value over time−Initial YI value

The components used in each example and comparative example are as follows.
PVA (1): sulfonic acid group-modified PVA, polymerization degree 1200, saponification degree 95.4 mol%, sulfonic acid group modification amount 4 mol%, 4% by mass aqueous viscosity (20 ° C.) 12.1 mPa · s
PVA (2): unmodified PVA, degree of polymerization 1300, degree of saponification 88.0 mol%, viscosity of 4% by mass aqueous solution (20 ° C.) 14 mPa · s
PVA (3): pyrrolidone ring group modified PVA, polymerization degree 1000, saponification degree 95.3 mol%, pyrrolidone ring modified group 6 mol%, 4% by mass aqueous solution viscosity (20 ° C.) 10 mPa · s
TMP: trimethylolpropane, reagent, manufactured by Wako Pure Chemical Industries, Ltd., molecular weight 134
D-GL: diglycerin, reagent, manufactured by Wako Pure Chemical Industries, Ltd., molecular weight 166
Glucose: glucose, reagent, manufactured by Fuji Film Wako Pure Chemical Industries, Ltd., molecular weight 180
A-80: "Lapisol A-80" manufactured by NOF Corporation, sodium di (2-ethylhexyl) -sulfosuccinate (active ingredient content: 80% by mass, water surface diffusing agent)
Dioctyl sodium sulfosuccinate: manufactured by Fuji Film Wako Pure Chemical Industries, Ltd., reagent (active ingredient amount: 96% by mass, water surface diffusing agent)
Inorganic particles: silica, "Sylysia 358" manufactured by Fuji Silysia Chemical Ltd.
Surfactant: polyoxyethylene monolaurate, "Nonion L4" manufactured by NOF Corporation

(Examples 1-3, 7-8, Comparative Examples 1-3)
[Production of PVA film]
Each component was dissolved and dispersed in water according to the formulation shown in Table 1 to prepare a 15% by mass aqueous PVA solution. The obtained PVA aqueous solution was applied onto a polyethylene terephthalate (PET) film (thickness: 50 μm) as a support member by a lip coater method. Thereafter, drying was performed at 70 ° C. for 10 minutes, and then at 110 ° C. for 10 minutes to form a PVA film (thickness: 40 μm) on the support member. The laminate composed of the support member and the PVA film was wound on a paper core having an inner diameter of 3 inches.

[Embossing]
The rolled-up laminate is fed out, the support member is peeled off, and the PVA film is embossed with a back-up roll (a wool paper roll manufactured by Yuri Roll Co., Ltd., surface hardness: 75 ° using an A-type hardness meter based on JIS K6253). Embossing was performed using a roll to obtain a water-soluble packaging film having a thickness of 15 μm. The embossing roll had a 40 mesh mesh pattern on the roll surface, and had a corrugated shape with a rectangular cross section along the width direction. The height difference and the pitch of the embossing roll were as shown in Table 2. The embossing was performed by passing the PVA film at a speed of 10 m / min while pressing the embossing roll heated to 100 ° C. and the backup roll at room temperature (23 ° C.) at a pressing force of 100 kg / cm. . Tables 2 and 3 show the evaluation results of the obtained water-soluble packaging film.

(Example 4)
The embossing was carried out in the same manner as in Example 3, except that the pressing force between the embossing roll and the backup roll was 80 kg / cm so as to obtain a water-soluble packaging film having a thickness of 28 μm.

(Example 5)
The operation was performed in the same manner as in Example 2 except that embossing was not performed.

(Example 6)
[Preparation of matte embossing roll]
On a roll made of iron whose surface is made of iron, diagonal embossing was performed with a mesh # 380 to a depth of 60 μm by a meal engraving method to form first irregularities. Thereafter, a chromium plating layer of about 5 μm was formed. Next, second irregularities were formed on the surface of the chromium plating layer by using a # 60 mesh by sandblasting to obtain a mat emboss roll.
[Production of PVA film]
A PVA film was produced in the same manner as in Example 1, except that the amount was changed as shown in Table 1.

[Matte embossing]
After unwinding the rolled-up laminate and peeling off the support member, a mat emboss roll and a backup roll (rubber roll manufactured by Yuri Roll Co., Ltd. (the surface is coated with synthetic rubber, hardness A90 °)) are used for the PVA film. Then, mat embossing was performed to obtain a water-soluble packaging film having a thickness of 40 μm. The mat embossing was performed by passing the PVA film at a speed of 10 m / min while pressing the PVA film between the mat embossing roll heated to 100 ° C. and the backup roll at room temperature at a pressing force of 100 kg / cm.

(Examples 9 and 10)
Example 1 was carried out in the same manner as in Example 1 except that embossing was not performed and the composition for obtaining the PVA aqueous solution was changed to the composition shown in Table 1.

* A-80 and dioctyl sodium sulfosuccinate in the formulation column indicate lapizol A-80 and parts by mass as reagents, respectively.

As is evident from the above results, the water-soluble packaging film of each example uses a modified PVA, and contains a predetermined amount of a plasticizer and a water surface diffusing agent, so that the film is put into water as a package. In addition, the diffusibility of the encapsulated drug was good. Furthermore, even when the package was formed under high temperature and high humidity, no problem occurred and the bag-making property was excellent.
On the other hand, the water-soluble packaging film of each comparative example does not contain a water surface diffusing agent or a modified PVA, or contains a plasticizer in an amount larger than a specified amount, so that the diffusibility of the drug is reduced or the high temperature is not obtained. Under high humidity conditions, stickiness occurred and the bag-forming property was reduced, and both the diffusivity of the drug and the bag-forming property were not excellent.

Claims (10)

1. Polyvinyl alcohol, a plasticizer, and a water-soluble packaging film containing a water surface diffusing agent,
   The polyvinyl alcohol contains a modified polyvinyl alcohol,
   Water-soluble packaging wherein the content of the plasticizer is 3 parts by mass or more and less than 10 parts by mass and the content of the water surface diffusing agent is 0.1 part by mass or more and 15 parts by mass or less with respect to 100 parts by mass of the polyvinyl alcohol. For film.
2. The water-soluble packaging film according to claim 1, wherein the modified polyvinyl alcohol is at least one selected from the group consisting of a pyrrolidone ring group-modified polyvinyl alcohol and a sulfonic acid group-modified polyvinyl alcohol.
3. The water-soluble packaging film according to claim 2, wherein the modified polyvinyl alcohol is a sulfonic acid group-modified polyvinyl alcohol.
4. 水溶 The water-soluble packaging film according to any one of claims 1 to 3, wherein the polyvinyl alcohol further contains unmodified polyvinyl alcohol.
5. The content of the modified polyvinyl alcohol is 30% by mass or more and 90% by mass or less with respect to the total amount of polyvinyl alcohol, and the content of the unmodified polyvinyl alcohol is 10% by mass or more and 70% by mass or less. 2. The water-soluble packaging film according to item 1.
6. (6) The water-soluble packaging film according to any one of (1) to (5), wherein the water surface diffusing agent is a dialkyl sulfosuccinate.
7. The water-soluble packaging film according to any one of claims 1 to 6, wherein the film surface has an uneven shape having a height difference of 10 µm or more and 200 µm or less.
8. The water-soluble packaging film according to any one of claims 1 to 7, which is used for agricultural chemical packaging.
9. A package comprising the water-soluble packaging film according to any one of claims 1 to 8, and a drug contained in the water-soluble packaging film.
10. The package according to claim 9, wherein the drug is an agricultural chemical.

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