Water-soluble film and packaging

Abstract

The present invention provides a water-soluble film having excellent peelability from a support, transparency and sealing properties when manufacturing the water-soluble film, and a packaging body of a medicine using the same. Also provided is a method for manufacturing a water-soluble film having these excellent properties. A water-soluble film containing a polyvinyl alcohol resin, wherein the proportion of fluorine in all elements (F1S) determined by analyzing the first surface of the water-soluble film by X-ray photoelectron spectroscopy is greater than 1 mol% and less than 25 mol%, and the proportion of fluorine in all elements (F1B) determined by analyzing the surface at a depth of 0.1 μm from the first surface by X-ray photoelectron spectroscopy is less than 0.5 mol%.

Description

Technical Field

[0001] The present invention relates to a water-soluble film containing a polyvinyl alcohol resin which is suitable for packaging of various medicines and the like, and a packaging body using the same. Background Art

[0002] Conventionally, water-soluble films have been widely used in applications such as detergents, pesticides, and various other chemicals, as well as packaging materials containing seeds, and the demand for such films has been increasing due to their simplicity.

[0003] As a water-soluble film used for this purpose, a PVA film having a polyvinyl alcohol resin (hereinafter, sometimes referred to as PVA) as a main component is widely used. Various technologies have been proposed to improve various physical properties of the PVA film. For example, a water-soluble film having improved water solubility by blending various additives such as a plasticizer or using modified PVA has been proposed (for example, Patent Document 1).

[0004] The water-soluble film disclosed in Patent Document 1 is improved in water solubility by adjusting the amount of plasticizer added or using modified PVA to reduce its crystallinity. However, hydrophilic PVA is used as the water-soluble film, and the interaction between PVA and metal materials is high. Therefore, when the water-soluble film is manufactured on a support such as a metal roller or a metal conveyor belt, the film has poor peelability from the support and is prone to surface roughness or uneven thickness. In the past, peelability was controlled by a method in which a surfactant was included in the water-soluble film.

[0005] However, in recent years, as the demand for water-soluble films has increased, there has been a demand for improved productivity. Productivity can be improved by increasing the film-making speed, but as the film-making speed increases, the peelability becomes insufficient using conventional technology, resulting in surface roughness or uneven thickness, which is a cause of reduced product yield.

[0006] On the other hand, in PVA films for optical purposes different from the purposes of the present invention, there is also the problem of poor peelability of the PVA film from the support during film formation, and a method of adding a fluorine-containing surfactant to the film-forming stock solution of the PVA film has been proposed (Patent Document 2). In addition, with respect to the same PVA film for optical purposes, a method of coating a casting substrate with a fluorine-containing resin to form a strong fluorine-based resin film has been proposed to improve peelability (Patent Document 3).

[0007] Previous technical literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Publication No. 2017-078166

[0010] Patent Document 2: Japanese Patent Application Publication No. 2006-307059

[0011] Patent Document 3: Japanese Patent Application Publication No. 2006-305924

[0012] However, in the technology of patent document 2, it is necessary to use more fluorinated surfactants, which is difficult to cope with environmental pollution caused by halogen substances, which has become a problem in recent years. In addition, the affinity between hydrophobic fluorinated substances and PVA is low, so it causes phase separation in the film, which easily damages the transparency of the film. In addition, when the technology is applied to a water-soluble film, if the film contains more fluorinated surfactants, when the film is sealed with each other based on water and / or heat after packaging the contents (hereinafter, sometimes referred to as sealing), poor sealing often occurs, and the contents leak from the sealing portion.

[0013] On the other hand, if the technology of Patent Document 3 is applied to a water-soluble film, the water-soluble film is more likely to adhere to each other due to moisture absorption than an optical film, and wrinkles or breaks may occur due to friction with the roll when the roll is unwound. In addition, forming a strong fluororesin layer on a support such as a roller or a conveyor belt is also likely to increase costs from the perspective of maintenance of the material surface and the support. Summary of the invention

[0014] Technical issues to be solved by the invention

[0015] The present invention aims to provide a water-soluble film having excellent peelability from a support, transparency and sealing properties when producing the water-soluble film, and a drug packaging body using the same. In addition, the present invention provides a method for producing a water-soluble film having these excellent properties.

[0016] Means for solving technical problems

[0017] As a result of in-depth research by the present inventors, it was discovered that the above-mentioned problem can be solved when the proportion of fluorine in all elements on the first surface of the water-soluble film is within a specific range and the proportion of fluorine at a position slightly approaching the center side in the thickness direction of the film from the first surface is below a certain value, and further in-depth research based on this understanding led to the completion of the present invention.

[0018] That is, the present invention is as follows.

[0019] [1] A water-soluble film comprising a polyvinyl alcohol resin, wherein:

[0020] When the first surface of the water-soluble film is analyzed by X-ray photoelectron spectroscopy, the proportion of fluorine element in all elements (F1S) is greater than 1 mol% and less than 25 mol%, and when the surface at a depth of 0.1 μm from the first surface is analyzed by X-ray photoelectron spectroscopy, the proportion of fluorine element in all elements (F1B) is less than 0.5 mol%.

[0021] [2] The water-soluble film according to [1], wherein

[0022] In the water-soluble film, when the second surface opposite to the first surface is analyzed by X-ray photoelectron spectroscopy, the proportion of fluorine in all elements (F2S) is greater than 1 mol% and less than 25 mol%, and when the surface at a depth of 0.1 μm from the second surface of the water-soluble film is analyzed by X-ray photoelectron spectroscopy, the proportion of fluorine in all elements (F2B) is less than 0.5 mol%.

[0023] [3] The water-soluble film according to [1] or [2], wherein

[0024] The difference between F1S and F2S is 2.5 mol % or more.

[0025] [4] The water-soluble film according to any one of [1] to [3], characterized in that:

[0026] The fluorine element is contained in the fluorine-containing surfactant having a molecular weight of 10,000 or less.

[0027] [5] The water-soluble film according to [4], wherein

[0028] The fluorine-containing surfactant is at least one selected from the group consisting of fluoroalkyl alcohols, fluoroalkyl carboxylates, fluoroalkyl sulfates, fluoroalkyl sulfonates, fluoroalkyl phosphates, fluoroalkyl phosphonates, fluoroalkyl hypophosphites and fluoroalkyl ammonium salts.

[0029] [6] The water-soluble film according to [5], wherein

[0030] The fluorine-containing surfactant is at least one selected from the group consisting of fluoroalkyl alcohols, fluoroalkyl phosphates, and fluoroalkyl sulfonates.

[0031] [7] A packaging body, wherein:

[0032] The water-soluble film described in [1] to [6] contains a drug.

[0033] [8] The packaging body according to [7], wherein:

[0034] The medicament is a pesticide, a detergent or a bactericide.

[0035] [9] The packaging body according to [7] or [8], wherein:

[0036] The medicine is in liquid form.

[0037]

[10] A method for producing a water-soluble film according to any one of [4] to [6], wherein:

[0038] A fluorinated surfactant is coated on a support, and a membrane-forming stock solution containing a polyvinyl alcohol resin is cast in a film-like state on the coated surface.

[0039]

[11] The method for producing a water-soluble film according to

[10] , wherein:

[0040] The solution or dispersion of the fluorine-containing surfactant is continuously applied to the support and dried to coat the support with the fluorine-containing surfactant.

[0041] Effects of the Invention

[0042] According to the present invention, a water-soluble film having excellent peelability from a support, transparency and sealing properties during film formation and a drug package using the same can be provided. In addition, according to the present invention, a water-soluble film having such excellent properties can be produced.

[0043] Furthermore, the water-soluble film of the present invention maintains the above-mentioned properties and is also excellent in suppressing adhesion between films due to moisture absorption. DETAILED DESCRIPTION

[0044] Hereinafter, the present invention will be described in detail.

[0045] In the present invention, it is important that the proportion of fluorine element in all elements (F1S) obtained by analyzing the first surface of the water-soluble film by X-ray photoelectron spectroscopy (hereinafter sometimes referred to as XPS) is 1 mol% or more and 25 mol% or less. When F1S is less than 1 mol%, the peeling property from the substrate during film formation becomes insufficient. F1S is preferably 1.5 mol% or more, more preferably 2 mol% or more, further preferably 2.5 mol% or more, and particularly preferably 3 mol% or more. On the other hand, when F1S exceeds 25 mol%, poor sealing is likely to occur when sealing the package. F1S is preferably 23 mol% or less, more preferably 21 mol% or less, further preferably 20 mol% or less, and particularly preferably 19 mol% or less.

[0046] In addition, in the present invention, it is also important that the proportion of fluorine element in all elements (F1B) obtained by XPS analysis of the surface at a depth of 0.1 μm from the first surface of the water-soluble film is 0.5 mol% or less. When F1B exceeds 0.5 mol%, poor sealing is also likely to occur when sealing the package. F1B is preferably 0.4 mol% or less, more preferably 0.3 mol% or less, and further preferably 0.2 mol% or less. F1B can be 0 mol%, that is, below the detection limit of the XPS measuring device. The detection limit of conventional XPS measuring devices is usually around 0.1 mol%.

[0047] In the present invention, the amount of fluorine and other elements on the surface of the water-soluble film is measured by XPS. XPS measurement refers to the process of irradiating the sample surface with X-rays to excite the inner shell electrons of atoms and detecting the kinetic energy of the electrons released thereby, thereby identifying and quantifying the elements present on the sample surface or analyzing the chemical bonding state.

[0048] In the present invention, the elements measured by XPS are carbon (1s orbital electron), nitrogen (1s orbital electron), oxygen (1s orbital electron), fluorine (1s orbital electron), sodium (1s orbital electron), silicon (2p orbital electron), phosphorus (2p orbital electron) and sulfur (2p orbital electron). These elements are quantified, and the ratio of fluorine element to the total amount thereof is set as F1S.

[0049] Furthermore, in XPS measurement, the film surface can be etched by C60 (fullerene) or argon clusters, etc., and analyzed in the depth direction. In the present invention, C60 was used to perform etching for 100 seconds under the conditions of an acceleration voltage of 10 kV, a sample current of 20 nA, and a scanning range of 0.5×2.0 mm, thereby exposing a surface approximately 0.1 μm deep from the film surface, and F1B was quantified.

[0050] In the present invention, when both surfaces of the water-soluble film are measured by XPS and the ratio of fluorine element in all elements on each surface is determined, the surface having a larger ratio of fluorine element is defined as the first surface.

[0051] In the present invention, the proportion of fluorine element in all elements (F2S) obtained by XPS analysis of the second surface of the water-soluble film opposite to the first surface is preferably 1 mol% or more. When F2S is less than 1 mol%, there is a tendency to easily produce adhesion between films. F2S is more preferably 1.5 mol% or more, further preferably 2 mol% or more, and particularly preferably 2.5 mol% or more. On the other hand, when F2S exceeds 25 mol%, there is a tendency to easily produce poor sealing when sealing the package. F2S is more preferably 23 mol% or less, further preferably 21 mol% or less, and particularly preferably 19 mol% or less.

[0052] In addition, in the present invention, the proportion of fluorine element in all elements (F2B) obtained by XPS analysis of the surface at a depth of 0.1 μm from the second surface of the water-soluble film is preferably 0.5 mol% or less. When F2B exceeds 0.5 mol%, there is also a tendency to easily produce poor sealing when the package is sealed. F2B is more preferably 0.4 mol% or less, further preferably 0.3 mol% or less, and particularly preferably 0.2 mol% or less. F2B can be 0 mol%, that is, below the detection limit of the XPS measuring device. The detection limit of the XPS measuring device is generally as described above.

[0053] Furthermore, in the present invention, the difference between F1S and F2S is preferably 2.5 mol% or more. When the difference between F1S and F2S is 2.5 mol% or more, there is a tendency that poor sealing is not easily caused. The difference between F1S and F2S is more preferably 3 mol% or more, and further preferably 4 mol% or more. In the present invention, the difference between F1S and F2S does not exceed 25 mol%.

[0054] <Polyvinyl alcohol resin>

[0055] The water-soluble film of the present invention contains polyvinyl alcohol resin (PVA). As PVA, PVA produced by saponifying a vinyl ester polymer obtained by polymerizing a vinyl ester monomer can be used. As the vinyl ester monomer, for example, vinyl formate, vinyl acetate, vinyl propionate, vinyl valerate, vinyl laurate, vinyl stearate, vinyl benzoate, 2,2-dimethyl vinyl propionate and vinyl versatate can be cited, among which vinyl acetate is preferred.

[0056] The above-mentioned vinyl ester polymer is preferably a vinyl ester polymer obtained by using only one or two or more vinyl ester monomers as a monomer, more preferably a vinyl ester polymer obtained by using only one vinyl ester monomer as a monomer, and may also be a copolymer of one or two or more vinyl ester monomers and a monomer copolymerizable therewith.

[0057] Examples of other monomers copolymerizable with the vinyl ester monomer include ethylene; olefins having 3 to 30 carbon atoms such as propylene, 1-butene, and isobutylene; acrylic acid or its salts; acrylic acid esters such as methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, and octadecyl acrylate; methacrylic acid or its salts; methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, 2-ethylhexyl methacrylate, dodecyl methacrylate, and octadecyl methacrylate; acrylamide, N-methyl-2-acrylamide, N-ethylacrylamide, N,N-dimethylacrylamide, diacetoneacrylamide, acrylamidepropanesulfonic acid or its salts, dimethylaminopropylacrylamide or its salts, N- Acrylamide derivatives such as hydroxymethyl acrylamide or its derivatives; methacrylamide derivatives such as methacrylamide, N-methyl methacrylamide, N-ethyl methacrylamide, methacrylamide propanesulfonic acid or its salt, dimethylaminopropyl methacrylamide or its salt, N-hydroxymethyl methacrylamide or its derivatives; N-vinylamides such as N-vinyl formamide, N-vinylacetamide, and N-vinyl pyrrolidone; vinyl ethers such as methyl vinyl ether, vinyl ethyl ether, n-propyl vinyl ether, isopropyl vinyl ether, vinyl n-butyl ether, vinyl isobutyl ether, tert-butyl vinyl ether, dodecyl vinyl ether, and octadecyl vinyl ether; vinyl cyanides such as acrylonitrile and methacrylonitrile; vinyl halides such as vinyl chloride, vinylidene chloride, vinyl fluoride, and vinylidene fluoride; acrylic compounds such as allyl acetate and allyl chloride; maleic acid or its salt, ester, or anhydride; itaconic acid or its salt, ester, or anhydride; vinyl silyl compounds such as vinyl trimethoxysilane; isopropenyl acetate, etc. The above-mentioned vinyl ester polymer may have structural units derived from one or more of these other monomers.

[0058] From the viewpoint of water solubility and film strength, the proportion of the structural units derived from the other monomers in the vinyl ester polymer is preferably 15 mol % or less, more preferably 5 mol % or less, based on the number of moles of all structural units constituting the vinyl ester polymer.

[0059] There is no particular restriction on the degree of polymerization of PVA, but the lower limit of the degree of polymerization is preferably 200 or more, more preferably 300 or more, and further preferably 500 or more from the viewpoint of film strength. On the other hand, the upper limit of the degree of polymerization is preferably 8,000 or less, more preferably 5,000 or less, and further preferably 3,000 or less from the viewpoint of the productivity of PVA or the productivity of water-soluble film. Here, the degree of polymerization means the average degree of polymerization measured in accordance with the description of JIS K 6726-1994. That is, in this specification, the degree of polymerization is calculated by the following formula based on the limiting viscosity [η] (unit: deciliter / g) measured in water at 30°C after saponification of the residual acetate groups of PVA and purification.

[0060] Po=([η]×10 4 / 8.29) (1 / 0.62)

[0061] In the present invention, the saponification degree of PVA is preferably 64 to 99.99 mol%. By setting the saponification degree within this range, it is easy to take into account the water solubility and mechanical physical properties of the film. The lower limit of the saponification degree is more preferably 70 mol% or more, and more preferably 75 mol% or more. On the other hand, the upper limit of the saponification degree is more preferably 99.96 mol% or less, and more preferably 99.93 mol% or less. Here, the saponification degree of PVA refers to the total molar number of the structural unit (typically a vinyl ester monomer unit) and the vinyl alcohol unit that can be converted into a vinyl alcohol unit by saponification of the PVA, and the proportion (mol%) occupied by the molar number of the vinyl alcohol unit. The saponification degree of PVA can be measured in accordance with the records of JIS K 6726-1994.

[0062] The water-soluble film of the present invention may use a single PVA as PVA, or may use a mixture of two or more PVAs having different polymerization degrees, saponification degrees, modification degrees, etc.

[0063] In the present invention, the content of PVA in the water-soluble film is not particularly limited, but is preferably 50% by mass, more preferably 80% by mass, and further preferably 85% by mass.

[0064] <Plasticizer>

[0065] PVA film is rigid compared with other plastic films when not including plasticizer, so that mechanical physical properties such as impact strength or process passability during secondary processing sometimes become problems. In order to prevent these problems, preferably contain plasticizer in the water-soluble film of the present invention. As preferred plasticizer, polyols can be enumerated, specifically, for example, polyols such as ethylene glycol, glycerine, diglycerine, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, trimethylolpropane, sorbitol, etc. can be enumerated. These plasticizers can be used alone or in combination of two or more. From the viewpoints of being difficult to ooze out to the film surface, among these plasticizers, ethylene glycol or glycerine are preferably used, and glycerine is more preferably used.

[0066] As the content of the plasticizer in the water-soluble film, relative to PVA100 mass parts included in the water-soluble film, preferably more than 1 mass part, more preferably more than 3 mass parts, more preferably more than 5 mass parts, and, preferably less than 70 mass parts, more preferably less than 50 mass parts, more preferably less than 40 mass parts. If the above-mentioned content is less than 1 mass part, then the improvement effect of mechanical physical properties such as impact strength may be insufficient. On the other hand, if the above-mentioned content exceeds 70 mass parts, then sometimes the film becomes too soft and operability is reduced, or oozes out to the film surface and various problems occur.

[0067] <Starch / Water-soluble polymer>

[0068] The film of the present invention may contain starch and / or a water-soluble polymer other than PVA for the purpose of imparting mechanical strength to the water-soluble film, maintaining moisture resistance when the film is used, or adjusting the rate of softening caused by water absorption when the film is dissolved.

[0069] Examples of starch include natural starches such as corn starch, potato starch, sweet potato starch, wheat starch, rice starch, tapioca starch, and sago starch; and processed starches that have been subjected to etherification, esterification, oxidation, and the like. Processed starches are particularly preferred.

[0070] The content of starch in the water-soluble film is preferably 15 parts by mass or less, more preferably 10 parts by mass or less, based on 100 parts by mass of PVA. If the content is more than 15 parts by mass, the process passability may be deteriorated.

[0071] Examples of water-soluble polymers other than PVA include dextrin, gelatin, glue, casein, shellac, gum arabic, polyacrylamide, sodium polyacrylate, polyvinyl methyl ether, a copolymer of methyl vinyl ether and maleic anhydride, a copolymer of vinyl acetate and itaconic acid, polyvinyl pyrrolidone, cellulose, acetyl cellulose, acetyl butyl cellulose, carboxymethyl cellulose, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, sodium alginate, and the like.

[0072] The content of water-soluble polymers other than PVA in the water-soluble film is preferably 15 parts by mass or less, more preferably 10 parts by mass or less, based on 100 parts by mass of PVA. If the content is more than 15 parts by mass, the water solubility of the film may be insufficient.

[0073] <Surfactant>

[0074] In the present invention, the water-soluble film preferably contains a surfactant from the viewpoint of its operability or suppression of film surface abnormalities (parting line, surface roughness, etc.) of the water-soluble film. There is no particular limitation on the type of surfactant, and examples thereof include anionic surfactants, nonionic surfactants, etc.

[0075] Examples of the anionic surfactant include hydroxy acid-type surfactants such as potassium laurate; sulfate-type surfactants such as octyl sulfate; and sulfonic acid-type surfactants such as dodecylbenzenesulfonate.

[0076] Examples of the nonionic surfactant include alkyl ether types such as polyoxyethylene lauryl ether and polyoxyethylene oleyl ether; alkyl phenyl ether types such as polyoxyethylene octylphenyl ether; alkyl ester types such as polyoxyethylene laurate; alkyl amine types such as polyethylene glycol laurylamide; alkyl amide types such as polyoxyethylene lauric acid amide; polypropylene glycol types such as polyoxyethylene polyoxypropanolamine ether; alkanolamide types such as lauramide diethanol and oleoyl diethanolamine; and propenyl phenyl ether types such as polyoxyalkylene propenyl phenyl ether.

[0077] The surfactant may be used alone or in combination of two or more. Among these surfactants, nonionic surfactants are preferred, and alkanolamide-type surfactants are particularly preferred, and dialkanolamides (e.g., diethanolamine, etc.) of aliphatic hydroxy acids (e.g., saturated or unsaturated aliphatic hydroxy acids having 8 to 30 carbon atoms, etc.) are further preferred.

[0078] The content of the surfactant in the water-soluble film is preferably 0.01 mass parts or more, more preferably 0.02 mass parts or more, and more preferably 0.05 mass parts or more relative to PVA100 mass parts. On the other hand, the upper limit of the content of the surfactant is preferably 5 mass parts or less, more preferably 1 mass part or less, more preferably 0.5 mass parts or less, and particularly preferably 0.3 mass parts or less. If the above-mentioned content is less than 0.02 mass parts, it is easy to produce problems such as the deterioration of the peelability of the film-making device when manufacturing the water-soluble film or the generation of agglomerations between the films. On the other hand, if the above-mentioned content is more than 5 mass parts, it is easy to produce problems such as the deterioration of the film appearance caused by the oozing out to the film surface or the agglomeration of the surfactant.

[0079] <Other ingredients>

[0080] The water-soluble film of the present invention may contain water, antioxidant, ultraviolet absorber, lubricant, cross-linking agent, colorant, filler, preservative, mildewproof agent, other polymer compounds and other components in addition to plasticizer, starch, water-soluble polymer and surfactant other than PVA, within the range that does not hinder the effect of the present invention. The proportion of the total value of each mass of PVA, plasticizer, starch, water-soluble polymer and surfactant other than PVA in the total mass of the water-soluble film of the present invention is preferably in the range of 60 to 100 mass%, more preferably in the range of 80 to 100 mass%, and further preferably in the range of 90 to 100 mass%.

[0081] PVA and the above-mentioned components are uniformly mixed with a solvent and adjusted as a film-making stock solution for manufacturing a water-soluble film. As long as the solvent used is a good solvent for PVA, any solvent such as water, alcohol, dimethyl sulfoxide, etc. can be used. Among them, water is preferred from the perspectives of cost, environmental load, and no need to recover the solvent. Only one solvent can be used, or two or more solvents can be used in combination.

[0082] In the present invention, there is no particular limitation on the method for adjusting the film-forming stock solution. For example, any method can be adopted, such as a method of dissolving PVA, additives such as plasticizers and surfactants using a dissolving tank, etc.; a method of melt-kneading PVA in a water-containing state with a plasticizer, surfactant, etc. when melt-kneading the PVA using a single-screw or twin-screw extruder, etc.

[0083] The volatile content of the film-forming stock solution (the concentration of volatile components such as solvents removed by volatilization or evaporation during film formation) is preferably in the range of 50 to 90% by mass, and more preferably in the range of 55 to 80% by mass. If the volatile content is less than 50% by mass, the viscosity of the film-forming stock solution becomes high, and film formation may become difficult. On the other hand, if the volatile content exceeds 90% by mass, the viscosity may become low, and the thickness uniformity of the film is easily damaged.

[0084] The volatile content of the membrane-forming stock solution was determined according to the following formula.

[0085] Volatile content of film-forming stock solution (mass %) = {(Wa-Wb) / Wa}×100

[0086] (Wa represents the mass (g) of the film-forming stock solution, and Wb represents the mass (g) of the film-forming stock solution after being dried in an electric drying machine at 105°C for 16 hours.)

[0087] <Method for producing water-soluble film>

[0088] In the present invention, the film-making method of the water-soluble film can be exemplified by using the above-mentioned film-making stock solution and performing film-making by a cast film method, a wet film method (discharge into a poor solvent), a rod wet film method, a gel film method (a method of temporarily cooling and gelling the film-making stock solution, extracting and removing the solvent to obtain a PVA film) or a combination thereof; a melt extrusion film-making method and an inflation film-making method, etc., in which the above-mentioned film-making stock solution is obtained by using an extruder, etc. and extruding it from a T-die, etc. to perform film-making. Among them, the cast film-making method and the melt extrusion film-making method can obtain a uniform film with high productivity, so they are preferred. The water-soluble film of the present invention has excellent peelability from a metal roll or a metal drum, so from the viewpoint of productivity, it is preferred to coat the PVA stock solution on a support such as a metal roll or a metal drum and dry and peel off the film-making method. Below, the cast film-making method and the melt extrusion film-making method of the water-soluble film are described.

[0089] When a water-soluble film is produced by a cast film method or a melt extrusion film method, the film-forming stock solution is cast in a film-like state onto a support such as a metal roller or a metal conveyor belt, and the heated solvent is removed and solidified to form a film. The solidified film is peeled off from the support, dried by a drying roller, a drying furnace, etc. as needed, and then heat-treated as needed, and wound up, thereby obtaining a long-sized water-soluble film in a roll.

[0090] In the present invention, as a method for adjusting the proportion of fluorine element (F1S and F2S) in the surface of the water-soluble film to be greater than 1 mol% and less than 25 mol%, there can be exemplified (1) a method of coating a fluorine-containing compound on the above-mentioned support and casting a film-forming solution containing PVA in a film-like manner on the coated surface; (2) a method of coating a fluorine-containing compound on a PVA film formed by casting a film-forming solution containing PVA in a film-like manner on the above-mentioned support; (3) a method of adding a fluorine-containing compound to a film-forming solution containing PVA and casting the film-forming solution in a film-like manner, etc. Among them, the above-mentioned method (1) is particularly preferred from the viewpoints of manufacturing cost, uniformity of fluorine on the film surface, etc. The method is described below.

[0091] In the present invention, the fluorinated compound is preferably a fluorinated surfactant having a molecular weight of 10000 or less, based on the ease of transfer to the surface of the water-soluble film. The molecular weight of the fluorinated surfactant is more preferably in the range of 150 to 9000, further preferably in the range of 300 to 8000, particularly preferably in the range of 400 to 7000, and most preferably in the range of 500 to 6000.

[0092] The solid or high-viscosity liquid fluorinated surfactant is used after being dissolved or decomposed in a suitable solvent such as water or alcohol. The low-viscosity liquid fluorinated surfactant can be used directly. As a method for coating the fluorinated surfactant on the support, any method can be used, such as a method of making a low-viscosity fluorinated surfactant or a high-viscosity fluorinated surfactant solution or dispersion (1) directly contact the support and then adjust the coating amount with a metering knife or the like; (2) a method of uniformly coating the dispersion by roller coating, etc. At this time, the support can be heated or blown with hot air, etc., as required, to dry the coated surface. Among them, from the viewpoint of uniformly coating the fluorinated surfactant on the support, it is preferred to continuously coat the solution or dispersion of the fluorinated surfactant on the support and dry it. Specifically, it is preferred to continuously coat the fluorinated surfactant on the support and dry it during the period when the film-making stock solution is cast onto the support after the PVA film is peeled off from the support.

[0093] <Fluorinated surfactant>

[0094] Examples of the fluorinated surfactant in the present invention include the following.

[0095] Examples include fluoroalkyl alcohols represented by the general formula RfOH,

[0096] Fluoroalkyl carboxylates represented by the general formula RfCOOM,

[0097] By the general formula Rf x OSO (3-x) Fluoroalkyl sulfate represented by M,

[0098] Fluorinated alkyl sulfonates represented by the general formula RfSO3M,

[0099] By the general formula Rf x OPO (3-x) Fluorinated alkyl phosphate represented by M,

[0100] Fluoroalkylphosphonates represented by the general formula RfPO3M,

[0101] Fluoroalkyl hypophosphites represented by the general formula RfPO2M and

[0102] By the general formula Rf x NH (4-x) M represents a fluoroalkylammonium salt, etc.

[0103] In these general formulae, Rf represents an alkyl group having 1 to 50 carbon atoms and containing a fluorine atom. Rf may contain an ether bond in the alkyl chain. M represents at least one counter cation or counter anion. Furthermore, x is 1 to 3 or 4.

[0104] Among these fluorinated surfactants, fluoroalkyl alcohols are neutral surfactants, fluoroalkyl carboxylates, fluoroalkyl sulfates, fluoroalkyl sulfonates, fluoroalkyl phosphates, fluoroalkyl phosphonates and fluoroalkyl hypophosphites are anionic surfactants, and fluoroalkyl ammonium salts are cationic surfactants.

[0105] The counter cation is not particularly limited, but examples thereof include Na + , Ca 2+ NH4 + Or a mixture thereof. Among them, Na + The counter anion is not particularly limited, but examples thereof include Cl - wait.

[0106] Specific examples of the fluoroalkyl alcohol include partially fluorinated alkyl alcohols such as monofluoromethylethanol, trifluoromethylethanol, trifluoromethylpropanol, trifluoromethylbutanol, and partially fluorinated higher alcohols; perfluoroalkyl alcohols such as trifluoromethanol, pentafluoroethanol, heptafluoropropanol, pentadecafluoroheptanol, heptadecafluorooctanol, and nonadecafluorononanol; and alkyl alcohols such as trifluoromethoxyethanol, trifluoromethoxypropanol, trifluoromethyl (polyoxyethylene) alcohol, heptafluoroethyl (polyoxyethylene) alcohol, trifluoromethyl (polyoxyperfluoroethylene) alcohol, and heptafluoroethyl (polyoxyperfluoroethylene) alcohol, which are each represented by the general formula Rf(ORf'): n Here, Rf' represents an alkylene group containing a fluorine atom, and n represents the degree of condensation.

[0107] As the fluoroalkyl carboxylates, specifically, partially fluorinated alkyl carboxylates such as monofluoromethylethyl carboxylates, trifluoromethylethyl carboxylates, trifluoromethylpropyl carboxylates, trifluoromethylbutyl carboxylates, and partially fluorinated higher fatty acid salts; perfluoroalkyl carboxylates such as trifluoromethyl carboxylates, pentafluoroethyl carboxylates, heptafluoropropyl carboxylates, pentafluoroheptyl carboxylates, heptadecafluorooctyl carboxylates, and nonadecafluorononyl carboxylates; and alkyl groups represented by the general formula Rf(ORf') such as trifluoromethoxyethyl carboxylates, trifluoromethoxypropyl carboxylates, trifluoromethyl (polyethylene oxide) carboxylates, pentafluoroethyl (polyethylene oxide) carboxylates, trifluoromethyl (polyoxyperfluoroethylene) carboxylates, and pentafluoroethyl (polyoxyperfluoroethylene) carboxylates. n Fluorinated alkyl carboxylate having an ether bond represented by COOM.

[0108] Specific examples of the fluoroalkyl sulfate salt include partially fluorinated alkyl sulfate salts such as monofluoromethyl ethyl sulfate salts, trifluoromethyl ethyl sulfate salts, trifluoromethyl propyl sulfate salts, trifluoromethyl butyl sulfate salts, and partially fluorinated higher alkyl sulfate salts; perfluoroalkyl sulfate salts such as trifluoromethyl sulfate salts, pentafluoroethyl sulfate salts, heptafluoropropyl sulfate salts, pentafluoroheptyl sulfate salts, heptadecafluorooctyl sulfate salts, and nonadecafluorononyl sulfate salts; and alkyl sulfate salts such as trifluoromethoxyethyl sulfate salts, trifluoromethoxypropyl sulfate salts, trifluoromethyl (polyethylene oxide) sulfate salts, pentafluoroethyl (polyethylene oxide) sulfate salts, trifluoromethyl (polyperfluoroethylene oxide) sulfate salts, and pentafluoroethyl (polyperfluoroethylene oxide) sulfate salts. n OSO3M represents a fluoroalkyl sulfate ester salt having an ether bond.

[0109] Specific examples of the fluoroalkyl sulfonate include partially fluorinated alkyl sulfonates such as monofluoromethyl ethyl sulfonate, trifluoromethyl ethyl sulfonate, trifluoromethyl propyl sulfonate, trifluoromethyl butyl sulfonate, and partially fluorinated higher alkyl sulfonates; perfluoroalkyl sulfonates such as trifluoromethyl sulfonate, pentafluoroethyl sulfonate, heptafluoropropyl sulfonate, pentafluoroheptyl sulfonate, heptadecafluorooctyl sulfonate, and nonadecafluorononyl sulfonate; and alkyl sulfonates such as trifluoromethoxyethyl sulfonate, trifluoromethoxypropyl sulfonate, trifluoromethyl (polyethylene oxide) sulfonate, pentafluoroethyl (polyethylene oxide) sulfonate, trifluoromethyl (polyoxyperfluoroethylene) sulfonate, and pentafluoroethyl (polyoxyperfluoroethylene) sulfonate. n The fluorinated alkyl sulfonate having an ether bond represented by SO3M may also be a diester or higher fluorinated alkyl group.

[0110] As the fluoroalkyl phosphate salt, specifically, partially fluorinated alkyl phosphate salts such as monofluoromethyl ethyl phosphate salt, trifluoromethyl ethyl phosphate salt, trifluoromethyl propyl phosphate salt, trifluoromethyl butyl phosphate salt, and partially fluorinated higher alkyl phosphate salts; perfluoroalkyl phosphate salts such as trifluoromethyl phosphate salt, pentafluoroethyl phosphate salt, heptafluoropropyl phosphate salt, pentafluoroheptyl phosphate salt, heptadecafluorooctyl phosphate salt, and nonadecafluorononyl phosphate salt; trifluoromethoxyethyl phosphate salt, trifluoromethoxypropyl phosphate salt, trifluoromethyl (polyethylene oxide) phosphate salt, pentafluoroethyl (polyethylene oxide) phosphate salt, trifluoromethyl (polyperfluoroethylene oxide) phosphate salt, pentafluoroethyl (polyperfluoroethylene oxide) phosphate salt, etc., including the fluoroalkyl phosphate salt represented by the general formula Rf(ORf') n OPO3M is a fluorinated alkyl phosphate salt having an ether bond. Furthermore, it may be a diester or higher fluorinated alkyl group.

[0111] As the fluoroalkylphosphonate, specifically, partially fluorinated alkylphosphonates such as monofluoromethylethylphosphonate, trifluoromethylethylphosphonate, trifluoromethylpropylphosphonate, trifluoromethylbutylphosphonate, and partially fluorinated higher alkylphosphonates; perfluoroalkylphosphonates such as trifluoromethylphosphonate, pentafluoroethylphosphonate, heptafluoropropylphosphonate, pentafluoroheptylphosphonate, heptadecafluorooctylphosphonate, and nonadecafluorononylphosphonate; and alkylphosphonates having the general formula: Rf(ORf’) n PO3M M represents a fluoroalkylphosphonate having an ether bond.

[0112] Specific examples of the fluoroalkyl hypophosphites include monofluoromethyl ethyl phosphite, trifluoromethyl ethyl phosphite, trifluoromethyl propyl phosphite, trifluoromethyl butyl phosphite, and partially fluorinated higher alkyl phosphites; perfluoroalkyl hypophosphites such as trifluoromethyl phosphite, pentafluoroethyl phosphite, heptafluoropropyl phosphite, pentafluoroheptyl phosphite, heptadecafluorooctyl phosphite, and nonadecafluorononyl phosphite; and alkyl hypophosphites such as trifluoromethoxyethyl phosphite, trifluoromethoxypropyl phosphite, trifluoromethyl (polyethylene oxide) phosphite, pentafluoroethyl (polyethylene oxide) phosphite, trifluoromethyl (polyoxyperfluoroethylene) phosphite, and pentafluoroethyl (polyoxyperfluoroethylene) phosphite, which are substituted by the general formula Rf(ORf'): n PO2M represents a fluorinated alkyl phosphite having an ether bond.

[0113] Specific examples of the fluoroalkylammonium salt include partially fluorinated alkylammonium salts such as monofluoromethylethylammonium salt, trifluoromethylethylammonium salt, trifluoromethylpropylammonium salt, trifluoromethylbutylammonium salt, and partially fluorinated higher alkylammonium salts; perfluoroalkylammonium salts such as trifluoromethylammonium salt, pentafluoroethylammonium salt, heptafluoropropylammonium salt, pentafluoroheptylammonium salt, heptadecafluorooctylammonium salt, and nonadecafluorononylammonium salt; and alkylammonium salts such as trifluoromethoxyethylammonium salt, trifluoromethoxypropylammonium salt, trifluoromethyl (polyethylene oxide) ammonium salt, pentafluoroethyl (polyethylene oxide) ammonium salt, trifluoromethyl (polyperfluoroethylene oxide) ammonium salt, and pentafluoroethyl (polyperfluoroethylene oxide) ammonium salt. n ) x Fluoroalkylammonium salt of an ether bond represented by NH(4-x)M.

[0114] In the present invention, as one of the methods for adjusting F1S and F1B within a specific range, it is possible to cite the selection of a fluorinated surfactant having an appropriate affinity with PVA. That is, when a fluorinated surfactant having excessive affinity with PVA is selected, the surfactant is easily diffused into the interior of the water-soluble film, which may make it difficult to obtain an improved effect of peelability. On the other hand, when a fluorinated surfactant with poor affinity with PVA is selected, the amount of surfactant transferred to the surface of the water-soluble film decreases, which easily produces adhesion caused by moisture absorption. According to this viewpoint, from the above-mentioned surfactants, it is preferred to use any one of fluoroalkyl alcohols, fluoroalkyl phosphates, and fluoroalkyl sulfonates. These surfactants can be used alone or in combination. In addition, they can also be combined with other surfactants within the scope of not hindering the effect of the present invention.

[0115] The crystallization of the PVA film cast onto the support is promoted during the heating and drying process on the support and in the subsequent drying process. In particular, the region with a high moisture content is heated, whereby the mobility of the PVA molecular chain becomes higher, so that the crystallization is promoted and the crystallinity becomes higher. Therefore, if the drying speed is too fast, the crystals cannot grow fully, which may lead to insufficient crystallinity. On the other hand, if the drying speed is too slow, there is a tendency that the crystal growth is promoted and the crystallite size becomes larger. In addition, if too much heat is applied, the crystallinity becomes larger, which may lead to insufficient water solubility.

[0116] The surface temperature of the support of the cast film stock solution is preferably 50 to 110°C. When the surface temperature is less than 50°C, crystallization proceeds as drying proceeds slowly, which not only deteriorates the water solubility but also prolongs the time required for drying, which tends to reduce productivity. In addition, if drying takes time, the fluorinated surfactant will penetrate into the interior of the film, which tends to deteriorate the peelability. When it exceeds 110°C, there is a tendency for abnormalities such as foaming to occur on the film surface, and as drying proceeds rapidly and the amorphous component increases, agglomeration caused by moisture absorption tends to occur. From the viewpoint of facilitating the adjustment of the penetration state of the fluorinated surfactant, the surface temperature is preferably 60 to 100°C, and more preferably 65 to 95°C.

[0117] The drying speed can also be adjusted by uniformly blowing hot air at a speed of 1 to 10 m / s to the entire area of ​​the non-contact surface side of the PVA film while heating the PVA film on the support. From the viewpoint of drying efficiency or drying uniformity, the temperature of the hot air blown to the non-contact surface side is preferably 50 to 150° C., more preferably 70 to 120° C.

[0118] The water-soluble film is preferably dried on the support to a volatility of 5 to 50% by mass and then peeled off. At this time, the fluorinated surfactant coated on the support is transferred to the surface of the water-soluble film in contact with the support (hereinafter sometimes referred to as the support surface).

[0119] As required, the water-soluble film peeled off from the support is further dried. There is no particular restriction on the drying method, and a method of contacting it with a drying furnace or a drying roller can be cited. When drying is performed by multiple drying rollers, it is preferred to contact one side and the other side of the film with the drying roller alternately to reduce the difference in physical properties between the two sides of the film. The number of drying rollers is preferably 3 or more, more preferably 4 or more, and more preferably 5 to 30. The temperature of the drying furnace and the drying roller is preferably above 40°C and below 110°C. The upper limit of the temperature of the drying furnace and the drying roller is preferably below 100°C, more preferably below 90°C, and more preferably below 85°C. If the temperature of the drying furnace and the drying roller is too high, the crystallinity becomes high, which may lead to a decrease in water solubility. On the other hand, the lower limit of the temperature of the drying furnace and the drying roller is more preferably above 45°C, and more preferably above 50°C. If the temperature of the drying furnace and the drying roller is too low, the crystallinity becomes low, which may lead to easy generation of agglomeration caused by moisture absorption.

[0120] The water-soluble film can be further heat-treated as needed. By heat-treating, the strength, water solubility, etc. of the film can be adjusted. The temperature of the heat treatment is preferably above 60°C and below 135°C. The upper limit of the heat treatment temperature is more preferably below 130°C. If the heat treatment temperature is too high, too much heat is applied, so the crystallinity becomes high, which may lead to a decrease in water solubility.

[0121] The water-soluble film thus produced is further subjected to humidity conditioning treatment, cutting of both ends (ear parts) of the film, etc. as necessary, and is wound in a roll shape on a cylindrical core and moisture-proof packaged to obtain a product.

[0122] In the present invention, the method for adjusting the proportion of fluorine element in all elements on the side opposite to the support body surface (hereinafter sometimes referred to as the open surface) includes: (1) a method of coating a fluorine compound on the open surface after film formation; (2) when a drying roller is used in the film forming process, a method of coating a fluorine-containing surfactant on the surface of the drying roller in contact with the open surface and transferring it to the open surface; (3) a method of transferring an excess amount of fluorine-containing surfactant to the support body surface and adjusting the winding tension when winding the film produced by film formation, thereby transferring a portion of the fluorine-containing surfactant on the support body surface to the open surface, etc.

[0123] Among them, from the viewpoint of film-making equipment cost or productivity, the method of (3) in which an excess amount of fluorinated surfactant is applied to the support surface and the winding tension when the film is wound up is adjusted, thereby transferring a portion of the fluorinated surfactant on the support surface to the open surface. The winding tension at this time is preferably 30 to 200 N / m. When the winding tension is less than 30 N / m, the amount of fluorinated surfactant transferred to the open surface of the film may be too small. On the other hand, when the winding tension exceeds 200 N / m, the amount of fluorinated surfactant transferred to the open surface of the film becomes excessive, which may cause film surface abnormalities such as wrinkles of the film. The winding tension is more preferably 40 N / m or more, more preferably 50 N / m or more, and more preferably 160 N / m or less, more preferably 120 N / m or less.

[0124] The volatile content of the water-soluble film finally obtained through the above series of treatments is preferably in the range of 1 to 5% by mass, more preferably in the range of 2 to 4% by mass.

[0125] The water-soluble film of the present invention preferably has a total dissolution time of less than 150 seconds when immersed in deionized water at 10°C. Since the total dissolution time is less than 150 seconds, it can be suitable for use as a packaging film for medicines, etc. The total dissolution time is more preferably less than 90 seconds, further preferably less than 60 seconds, and particularly preferably less than 45 seconds. On the other hand, there is no particular restriction on the lower limit of the total dissolution time, but in a water-soluble film with an overly short total dissolution time, there is a tendency to easily produce problems such as agglomeration between the films or a decrease in film strength caused by moisture absorption in the atmosphere, and therefore it is preferably more than 5 seconds, more preferably more than 10 seconds, further preferably more than 15 seconds, and particularly preferably more than 20 seconds.

[0126] There is no particular restriction on the thickness of the water-soluble film of the present invention, but if the thickness is too thick, there is a tendency for the secondary processability to deteriorate, so it is preferably less than 200 μm, more preferably less than 150 μm, further preferably less than 100 μm, and particularly preferably less than 50 μm. In addition, when the thickness is too thin, problems may arise in the mechanical strength of the water-soluble film, so it is preferably more than 5 μm, more preferably more than 10 μm, further preferably more than 15 μm, and particularly preferably more than 20 μm. In addition, the thickness of any 10 places (for example, any 10 places located on a straight line drawn along the length direction of the water-soluble film) can be measured, and their average value is obtained as the thickness of the water-soluble film.

[0127] <Application>

[0128] The water-soluble film of the present invention has an excellent balance between water solubility and mechanical strength, and can be suitably used in various water-soluble film applications. Examples of such water-soluble films include films for drug packaging, base films for hydraulic transfer, base films for embroidery, release films for artificial marble molding, films for seed packaging, and films for waste storage bags. Among them, the water-soluble film of the present invention is preferably used as a film for drug packaging from the viewpoint of more significantly exerting the effects of the present invention.

[0129] As the types of medicaments when the water-soluble film of the present invention is used as a film for medicament packaging, pesticides, detergents (including bleaching agents) and bactericides can be cited. There is no particular restriction on the physical properties of the medicament, which can be acidic, neutral, or alkaline. In addition, boron-containing compounds can also be included in the medicament. As the shape of the medicament, it can be any one of powder, block, gel and liquid. There is no particular restriction on the packaging method, and it is preferably a unit packaging method in which the medicament is packaged in unit quantity (preferably sealed packaging). By packaging the medicament with the film of the present invention as a film for medicament packaging, the package of the present invention can be obtained.

[0130] Example

[0131] Hereinafter, the present invention will be specifically described by way of examples, etc., but the present invention is not limited to the following examples in any way. In addition, the evaluation items and methods used in the following examples and comparative examples are as follows.

[0132] (1) X-ray photoelectron spectroscopy (XPS)

[0133] (1-1) Analysis of the ratio of fluorine to all elements on the surface of water-soluble films

[0134] The film was cut into a size of 5 mm x 5 mm and placed on a measuring stand via a conductive double-sided tape. During the measurement, both sides of the film were measured, and the value of the side with a larger amount of fluorine was used. Each sample was measured under the following measurement conditions.

[0135] Measuring device: Ohi Quantera SXM (ULVAX―PHI.INC.)

[0136] Analysis software: Multi Pack ver9.0 (ULVAX―PHI.INC.) X-ray source: Monochromated Al Kα (1486.6eV)

[0137] X-ray beam diameter: 100μmφ (25W, 15kV)

[0138] Measuring range: 100μm×300μm

[0139] Signal receiving angle: 45°

[0140] Charge neutralization conditions: neutralization electron gun, Ar+ ion gun

[0141] Vacuum degree: 1×10 -6 Pa

[0142] Measured elements (peak value of excited inner shell electrons used for quantitative analysis): C(1s), N(1s), O(1s), F(1s), Na(1s), Si(2p), P(2p), S(2p)

[0143] The obtained spectrum was analyzed and the proportion of fluorine in all elements on the film surface was calculated.

[0144] (1-2) Analysis of the ratio of fluorine to all elements at a depth of 0.1 μm from the surface

[0145] In the XPS analysis device, the film was etched to a depth of 0.1 μm using C60, and then the amount of elements in the film at a depth of 0.1 μm was quantified under the same conditions as above, and the proportion of fluorine in all elements was calculated.

[0146] (Etching Process Conditions)

[0147] Measurement conditions: Acceleration voltage 10kV

[0148] Sample current: 20mA

[0149] Scanning range: 0.5mm×2.0mm

[0150] Etching speed: 1.0nm / min

[0151] (2) Evaluation of peelability from support

[0152] When the water-soluble film was produced, the peeling state of the film from the support was observed with the naked eye and evaluated according to the following criteria.

[0153] Evaluation criteria for peelability:

[0154] A... The peeling position is horizontal in the width direction, and no wrinkles or stretching occurs on the film surface.

[0155] B: The peeling position is horizontal in the width direction, and wrinkles and stretching occur on the film surface.

[0156] C... The peeling position is wavy in the width direction, and wrinkles and stretching are generated on the film surface.

[0157] (3) Sealing evaluation

[0158] The sealing properties between film surfaces in which the ratio of fluorine element to all elements was low were evaluated.

[0159] (3-1) Pre-adjustment

[0160] Rectangular test pieces (two for each sample) of about 30 cm in the film flow direction (MD) and about 10 cm in the width direction (TD) were cut from the water-soluble film and kept in an environment of 10°C-35% RH for more than 16 hours.

[0161] (3-2) Film bonding

[0162] In an environment of 10℃-35%RH, a piece of the above-mentioned pre-adjusted film was placed on the table, and the four corners of the film were fixed with tape. Furthermore, another piece of film was overlapped on it, and the two ends of one side of the 10cm side were fixed with tape, and a 140 / 10 anilox ink transfer roller was used to allow the unfixed end to pass to the ESIPROOF proofing roller. 0.5mL of deionized water was poured on the scraper of the ESIPROOF proofing roller, and the roller was pulled at a speed of about 7.5cm / second to bond the two films. In addition, at this time, the roller was not pulled to the end of the film and a portion that was not bonded to the end of the film was left so that it could be set on the chuck of the tensile testing machine. Three 25mm wide strip-shaped test pieces were cut out along the MD from the bonded water-soluble film.

[0163] (3-3) Measurement of sealing strength

[0164] After lamination and leaving for 10 minutes, the test piece was placed in a tensile testing machine and peeled according to the T-type peel test based on JIS K6854-3: 1999, and the average peel force of the three test pieces obtained was set as the adhesive force. In this test, the measurement condition was set to a tensile speed of 30 mm / min.

[0165] Evaluation criteria:

[0166] A…Excellent sealing…Seal strength standard: more than 5N / 25mm

[0167] B…slightly poor sealing…sealing strength standard: 1~5N / 25mm

[0168] C…Unable to seal…Seal strength standard: less than 1N / 25mm

[0169] (4) Transparency evaluation

[0170] Although a green-colored liquid (virtual detergent) was packaged in each film, transparency was evaluated based on the visual visibility of the content.

[0171] Evaluation criteria:

[0172] A…Excellent transparency, transparent and clear without turbidity. …Standard: Total haze value is less than 50%

[0173] B…Although slightly turbid, it is transparent and not turbid. …Standard: Total haze value is 50-70%

[0174] C…The film looks cloudy, opaque and not clearly visible. …Standard: Total haze value is 70% or more

[0175] (5) Film adhesion evaluation

[0176] The water-soluble PVA film was cut into 3cm×20cm, and after rolling it into a cylindrical shape with an inner diameter of about 1cm with the short side as the axis, the two ends were cut. Thus, a smaller water-soluble film roll with an inner diameter of 1cm and a width of 1cm was produced. A long tail clip with a mouth width of 15mm (manufactured by KOKUYO Co., Ltd., product name Scel-bo, "Scel-bo" is a registered trademark of KOKUYO Co., Ltd.) was used to clamp the vicinity of the central axis of the obtained roll in such a way that the direction of the clamping part of the clip was consistent with the axial direction of the roll, and it was stored under the conditions of 60℃-90%RH for 16 hours. After unwinding the film roll for storage, the adhesion state between the contact surfaces at the ends was evaluated.

[0177] Evaluation criteria:

[0178] A... There is no adhesion between the contact surfaces at the end, and the water-soluble film is unwound without resistance.

[0179] B… Resistance is felt when unwinding, but the water-soluble film can be unwound if force is applied.

[0180] C... The end contact surfaces were not adhered to each other, and the water-soluble film could not be unwound.

[0181] <Example 1>

[0182] On a metal roll (first drying roll) serving as a support for film formation, a 0.1 mass % aqueous dispersion of a fluoroalkyl alcohol (fluoroalkyl alcohol: hereinafter sometimes referred to as FTOHs) as a fluorinated surfactant was continuously applied by a roll coater so that the aqueous dispersion became 2.5 g / m 2 The amount of FTOHs was continuously coated on the surface of the metal roller by spraying hot air at 80°C and drying it.

[0183] On this basis, a film-forming stock solution with a volatile content of 60% by mass was prepared by adjusting methyl maleate (hereinafter sometimes referred to as MA) modified PVA (saponification degree 99.9 mol%, polymerization degree 1700, MA modification amount 5 mol%) obtained by saponifying polyvinyl acetate, 50 parts by mass of glycerol as a plasticizer, 2.0 parts by mass of lauramide diethanol as a surfactant, and water, and a filtered film-forming stock solution was obtained. The obtained film-forming stock solution was continuously discharged from the T-die onto the first drying roller (surface temperature 80°C) coated with FTOHs in a film shape, and hot air at 85°C was blown to the entire open surface of the first drying roller at a speed of 5 m / sec to dry it. Next, the film was peeled off from the first drying roller, and after drying on the second drying roller at a roller surface temperature of 75° C. in a manner such that the open surface and the support surface were alternately in contact with each drying roller, it was wound up at a winding tension of 90 N / m to obtain a water-soluble film (thickness 35 μm, width 1200 m) roll.

[0184] The water-soluble film was selected from the obtained film roll, and the fluorine content was measured by XPS. The results showed that F1S was 16.7 mol%, F1B was below the detection limit (<0.1 mol%), and F2S was 9.4 mol%, and F2B was below the detection limit (<0.1 mol%). The evaluation results of the peelability, sealing performance, content visibility and film adhesion of the metal roller were all good.

[0185] <Example 2>

[0186] A water-soluble film was obtained in the same manner as in Example 1 except that MA-modified PVA having a saponification degree of 88 mol % was used.

[0187] <Example 3>

[0188] A water-soluble film was obtained in the same manner as in Example 1 except that the amount of the plasticizer was 30 parts by mass.

[0189] <Example 4>

[0190] A water-soluble film was obtained in the same manner as in Example 1 except that PVA was modified with monomethyl maleate (hereinafter, sometimes referred to as MMM) having a modification rate of 2 mol % and a saponification degree of 88 mol % and the amount of the plasticizer was 25 parts by mass.

[0191] <Examples 5 and 6>

[0192] A water-soluble film was obtained in the same manner as in Example 1 except that 4-[(undecafluorohexenyl)oxy]benzenesulfonic acid sodium salt and tris(2,2,2-trifluoroethyl)phosphite were used as the fluorine-containing surfactant, respectively.

[0193] <Examples 7 and 8>

[0194] The amount of the aqueous dispersion of the fluorinated surfactant applied to the first drying roller was set to 1.1 g / m 2 , 8.1g / m 2 , a water-soluble film was obtained in the same manner as in Example 4 except for this.

[0195] <Example 9>

[0196] A water-soluble film was obtained in the same manner as in Example 1 except that the FTOHs dispersion was continuously applied and dried on the second drying roll with the open surface in the same manner as the first drying roll.

[0197] <Comparative Example 1>

[0198] The coating amount of the aqueous dispersion of the fluorinated surfactant was set to 24.6 g / m 2 , except for this, a water-soluble film was obtained in the same manner as in Example 1. The film had F1S of 38.5 mol %, F1B of 1.2 mol %, good peelability from a roll, but poor sealing property.

[0199] <Comparative Example 2>

[0200] A water-soluble film was obtained in the same manner as in Example 1 except that after applying the aqueous dispersion of the fluorinated surfactant, drying was performed using only the residual heat of the first drying roller instead of hot air drying. The film had F1S of 5.6 mol %, F1B of 3.2 mol %, and poor releasability from the roller.

[0201] <Comparative Example 3>

[0202] Instead of applying the fluorine-containing surfactant, an ethanol solution of a fluorine-containing resin (dichloropentafluoropropane (HCFC-225)) was applied to the roll and dried, and the fluorine resin coating was performed. Except for this, a water-soluble film was obtained in the same manner as in Example 1. Although the film had excellent releasability, when the film roll was rolled back, the films adhered to each other or adhered to the inside of the conveying roller, and wrinkles were generated in the film.

[0203] <Comparative Examples 4 and 5>

[0204] Instead of applying the fluorinated surfactant, FTOHs was added to the PVA film-forming stock solution to a concentration of 5000 ppm or 100 ppm and film-forming was performed, and water-soluble films were obtained in the same manner as in Example 1. The peelability of these films was good in Comparative Example 4, but poor in the film of Comparative Example 5, and both films had poor transparency and were turbid films.

[0205] Table 1 shows the evaluation results of the obtained films.

[0206]

[0207] As can be seen from the above results, the water-soluble film of the present invention has excellent peelability from the support, and has excellent sealing and transparency. In addition, the adhesion of the film is also suppressed. The water-soluble film of the present invention has excellent sealing and transparency, and the adhesion of the film is suppressed, so it is suitable for use as a film for drug packaging, a base film for hydraulic transfer, a base film for embroidery, a peeling film for artificial marble molding, a seed packaging film, and a film for a dirt storage bag. In particular, the water-soluble film of the present invention is suitable for use as a film for drug packaging for packaging drugs such as pesticides, detergents (including bleaching agents) and bactericides.

Claims

1. A water-soluble film comprising a polyvinyl alcohol resin, wherein: The ratio F1S of fluorine in all elements obtained by analyzing the first surface of the water-soluble film by X-ray photoelectron spectroscopy is greater than 1 mol% and less than 25 mol%, and the ratio F1B of fluorine in all elements obtained by analyzing the surface at a depth of 0.1 μm from the first surface by X-ray photoelectron spectroscopy is less than 0.5 mol%, The fluorine element is contained in a fluorine-containing surfactant having a molecular weight of less than 10,000. The fluorinated surfactant is at least one selected from the group consisting of fluoroalkyl alcohols, fluoroalkyl carboxylates, fluoroalkyl sulfates, fluoroalkyl sulfonates, fluoroalkyl phosphates, fluoroalkyl phosphonates, fluoroalkyl hypophosphites and fluoroalkyl ammonium salts, The fluoroalkyl carboxylate is at least one selected from the group consisting of monofluoromethylethyl carboxylate, trifluoromethylethyl carboxylate, trifluoromethylpropyl carboxylate, trifluoromethylbutyl carboxylate, trifluoromethyl carboxylate, pentafluoroethyl carboxylate, heptafluoropropyl carboxylate, trifluoromethoxyethyl carboxylate, trifluoromethoxypropyl carboxylate, trifluoromethyl (polyethylene oxide) carboxylate, pentafluoroethyl (polyethylene oxide) carboxylate, trifluoromethyl (polyperfluoroethylene oxide) carboxylate and pentafluoroethyl (polyperfluoroethylene oxide) carboxylate, The fluoroalkyl sulfonate is at least one selected from the group consisting of monofluoromethyl ethyl sulfonate, trifluoromethyl ethyl sulfonate, trifluoromethyl propyl sulfonate, trifluoromethyl sulfonate, pentafluoroethyl sulfonate, heptafluoropropyl sulfonate, trifluoromethoxy ethyl sulfonate, trifluoromethoxy propyl sulfonate, trifluoromethyl (polyethylene oxide) sulfonate, pentafluoroethyl (polyethylene oxide) sulfonate, trifluoromethyl (polyoxyperfluoroethylene) sulfonate and pentafluoroethyl (polyoxyperfluoroethylene) sulfonate.

2. The water-soluble film according to claim 1, wherein In the water-soluble film, when the second surface opposite to the first surface is analyzed by X-ray photoelectron spectroscopy, the proportion of fluorine element in all elements F2S is greater than 1 mol% and less than 25 mol%, and when the surface at a depth of 0.1 μm from the second surface is analyzed by X-ray photoelectron spectroscopy, the proportion of fluorine element in all elements F2B is less than 0.5 mol%.

3. The water-soluble film according to claim 2, wherein: The difference between F1S and F2S is 2.5 mol % or more.

4. The water-soluble film according to claim 1, characterized in that: The fluorine element is contained in the fluorine-containing surfactant having a molecular weight of 150 to 9,000.

5. The water-soluble film according to claim 1, wherein The fluorine-containing surfactant is at least one selected from the group consisting of fluoroalkyl alcohols, fluoroalkyl phosphates, and fluoroalkyl sulfonates.

6. A packaging body, wherein: A water-soluble film containing a polyvinyl alcohol resin for storing a drug, wherein in the water-soluble film, a ratio F1S of fluorine in all elements determined by analyzing a first surface of the water-soluble film by X-ray photoelectron spectroscopy is greater than 1 mol% and less than 25 mol%, and a ratio F1B of fluorine in all elements determined by analyzing a surface at a depth of 0.1 μm from the first surface by X-ray photoelectron spectroscopy is less than 0.5 mol%, The fluorine element is contained in a fluorine-containing surfactant having a molecular weight of less than 10,000. The fluorinated surfactant is at least one selected from the group consisting of fluoroalkyl alcohols, fluoroalkyl carboxylates, fluoroalkyl sulfates, fluoroalkyl sulfonates, fluoroalkyl phosphates, fluoroalkyl phosphonates, fluoroalkyl hypophosphites and fluoroalkyl ammonium salts, The fluoroalkyl carboxylate is at least one selected from the group consisting of monofluoromethylethyl carboxylate, trifluoromethylethyl carboxylate, trifluoromethylpropyl carboxylate, trifluoromethylbutyl carboxylate, trifluoromethyl carboxylate, pentafluoroethyl carboxylate, heptafluoropropyl carboxylate, trifluoromethoxyethyl carboxylate, trifluoromethoxypropyl carboxylate, trifluoromethyl (polyethylene oxide) carboxylate, pentafluoroethyl (polyethylene oxide) carboxylate, trifluoromethyl (polyperfluoroethylene oxide) carboxylate and pentafluoroethyl (polyperfluoroethylene oxide) carboxylate, The fluoroalkyl sulfonate is at least one selected from the group consisting of monofluoromethyl ethyl sulfonate, trifluoromethyl ethyl sulfonate, trifluoromethyl propyl sulfonate, trifluoromethyl sulfonate, pentafluoroethyl sulfonate, heptafluoropropyl sulfonate, trifluoromethoxy ethyl sulfonate, trifluoromethoxy propyl sulfonate, trifluoromethyl (polyethylene oxide) sulfonate, pentafluoroethyl (polyethylene oxide) sulfonate, trifluoromethyl (polyoxyperfluoroethylene) sulfonate and pentafluoroethyl (polyoxyperfluoroethylene) sulfonate.

7. The packaging body according to claim 6, wherein: The medicament is a pesticide, a detergent or a bactericide.

8. The packaging body according to claim 6, wherein: The medicine is in liquid form.

9. The packaging body according to claim 6, wherein: In the water-soluble film, when the second surface opposite to the first surface is analyzed by X-ray photoelectron spectroscopy, the proportion of fluorine element in all elements F2S is greater than 1 mol% and less than 25 mol%, and when the surface at a depth of 0.1 μm from the second surface is analyzed by X-ray photoelectron spectroscopy, the proportion of fluorine element in all elements F2B is less than 0.5 mol%.

10. The packaging body according to claim 9, wherein: The difference between F1S and F2S is 2.5 mol % or more.

11. The packaging body according to claim 6, characterized in that: The fluorine element is contained in the fluorine-containing surfactant having a molecular weight of 150 to 9,000.

12. The packaging body according to claim 11, wherein: The fluorine-containing surfactant is at least one selected from the group consisting of fluoroalkyl alcohols, fluoroalkyl phosphates, and fluoroalkyl sulfonates.

13. A method for producing a water-soluble film containing a polyvinyl alcohol resin, wherein: A fluorinated surfactant is coated on a support, and a film-forming stock solution containing a polyvinyl alcohol resin is cast in a film-like state on the coated surface. In the water-soluble film, the ratio F1S of fluorine in all elements determined by analyzing the first surface of the water-soluble film by X-ray photoelectron spectroscopy is greater than 1 mol% and less than 25 mol%, and the ratio F1B of fluorine in all elements determined by analyzing the surface at a depth of 0.1 μm from the first surface by X-ray photoelectron spectroscopy is less than 0.5 mol%, and the fluorine-containing surfactant having a molecular weight of less than 10,000 contains the fluorine element, The fluorinated surfactant is at least one selected from the group consisting of fluoroalkyl alcohols, fluoroalkyl carboxylates, fluoroalkyl sulfates, fluoroalkyl sulfonates, fluoroalkyl phosphates, fluoroalkyl phosphonates, fluoroalkyl hypophosphites and fluoroalkyl ammonium salts, The fluoroalkyl carboxylate is at least one selected from the group consisting of monofluoromethylethyl carboxylate, trifluoromethylethyl carboxylate, trifluoromethylpropyl carboxylate, trifluoromethylbutyl carboxylate, trifluoromethyl carboxylate, pentafluoroethyl carboxylate, heptafluoropropyl carboxylate, trifluoromethoxyethyl carboxylate, trifluoromethoxypropyl carboxylate, trifluoromethyl (polyethylene oxide) carboxylate, pentafluoroethyl (polyethylene oxide) carboxylate, trifluoromethyl (polyperfluoroethylene oxide) carboxylate and pentafluoroethyl (polyperfluoroethylene oxide) carboxylate, The fluoroalkyl sulfonate is at least one selected from the group consisting of monofluoromethyl ethyl sulfonate, trifluoromethyl ethyl sulfonate, trifluoromethyl propyl sulfonate, trifluoromethyl sulfonate, pentafluoroethyl sulfonate, heptafluoropropyl sulfonate, trifluoromethoxy ethyl sulfonate, trifluoromethoxy propyl sulfonate, trifluoromethyl (polyethylene oxide) sulfonate, pentafluoroethyl (polyethylene oxide) sulfonate, trifluoromethyl (polyoxyperfluoroethylene) sulfonate and pentafluoroethyl (polyoxyperfluoroethylene) sulfonate.

14. The method for producing a water-soluble film according to claim 13, wherein: The solution or dispersion of the fluorine-containing surfactant is continuously applied to the support and dried to coat the support with the fluorine-containing surfactant.

15. The method for producing a water-soluble film according to claim 13, wherein: The fluorine-containing surfactant is at least one selected from the group consisting of fluoroalkyl alcohols, fluoroalkyl phosphates, and fluoroalkyl sulfonates.

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