Method for producing water-soluble film, water-soluble film, package, and drug package

Abstract

Provided is a method for producing a water-soluble film which does not cause discoloration, does not contain an undissolved substance of a water-soluble polymer, and has excellent blocking resistance, said method comprising: mixing / dissolving a water-soluble polymer (A) and water in a multi-screw extruder to obtain a resin composition (Z); and extruding the obtained resin composition (Z) from a nozzle and forming a film into a water-soluble film, the multi-screw extruder having a plurality of temperature-adjustable cylinders and a plurality of screws configured by combining a plurality of screw elements, and when the temperature-adjustable cylinders are set as C1, C2, C3,..., respectively from the upstream, when CS is a cylinder provided with a raw material supply port for supplying a raw material containing a water-soluble polymer (A) as the main component, and CT is a cylinder provided with a raw material supply port at the most upstream of the raw material supply ports for supplying a raw material containing water, T-S is 0 < = T < = 6, and the ratio of the effective length of the screw to the diameter of the screw is more than 50 and 100 or less.

Description

Technical Field

[0001] The present invention relates to a method for producing a water-soluble film by extruding a resin composition (Z) from a nozzle and forming a film, and a water-soluble film obtained by the above-mentioned production method, wherein the resin composition (Z) is a mixture of a water-soluble polymer (A) and water obtained by mixing / dissolving a water-soluble polymer (A) and water in a multi-screw extruder as a main component. Background Art

[0002] Water-soluble films have been used in a wide range of fields. Among them, water-soluble films made of polyvinyl alcohol-based resins are widely used in individual packages (unit packages) of pesticides, detergents and other chemicals, and in food packages.

[0003] As a method for producing a water-soluble film, the following method is generally known: a raw material composition containing a water-soluble polymer such as a polyvinyl alcohol-based resin is dissolved or dispersed in a solvent such as water, mixed, and degassed. After the mixture (film-forming raw material) is prepared, the film-forming raw material is discharged from a nozzle, cast on a casting surface such as an endless belt, a metal surface of a roller, a plastic substrate surface, and dried, thereby forming a film.

[0004] In addition, as a method for mixing and dissolving or dispersing a water-soluble polymer with a solvent, the following methods are used: a method of dissolving by stirring with a stirring blade while heating in a container such as a tank; a method of mixing and dissolving with a screw while heating in an extruder; etc.

[0005] As a method for producing a water-soluble film by mixing and dissolving a water-soluble polymer and a solvent in an extruder, for example, the following production methods are known: a production method comprising the steps of supplying a powdered polyvinyl alcohol resin to a twin-screw extruder, and supplying a solvent for liquefying the polyvinyl alcohol resin (see Patent Document 1); a production method characterized in that a multi-screw extruder without a vent is used, the temperatures of the head, the die outlet, and the boiling point of the liquid are controlled, and the back pressure in the die is adjusted to a specified range (see Patent Document 2).

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Publication No. 2002-254492

[0009] Patent Document 2: Japanese Patent Application Publication No. 2015-182372 Summary of the invention

[0010] Problem that the invention aims to solve

[0011] Yet, in the water-soluble film used in the pharmaceutical packaging purposes in particular, require to satisfy excellent cold water solubility, the storage stability to various medicaments, other various physical properties, the water-soluble polymer that becomes main component, the kind of additive is also multiple, result relies on the known manufacture method in the past as patent documentation 1, patent documentation 2, the undissolved thing of water-soluble polymer remains in resin combination (film making raw material), the formability of the water-soluble film obtained, the mechanical physical property reduction or anti-blocking property of the packaging body formed using the water-soluble film are not sufficient, therefore, seek further improvement.In addition, resin combination is sometimes colored, and the outward appearance of the water-soluble film obtained is damaged, therefore, seek further improvement.

[0012] Therefore, in this context, the present invention provides a method for producing a water-soluble film by mixing / dissolving a water-soluble polymer with water in a multi-screw extruder, wherein the film is not colored, has no undissolved water-soluble polymer, and has excellent anti-blocking properties.

[0013] Solutions for solving problems

[0014] Therefore, in view of the above situation, the inventors of the present invention have conducted in-depth research and found that by using a multi-screw extruder in which the ratio of the effective length to the diameter of the screw is greater than the previous specific range, the positional relationship between the barrel of the raw material supply port for supplying a raw material mainly composed of a water-soluble polymer and the barrel of the raw material supply port arranged at the upstreammost portion of the raw material supply port for supplying a raw material containing water is specifically configured, thereby solving the above-mentioned problem.

[0015] That is, the present invention has the following aspects.

[0016] [1] A method for producing a water-soluble film, comprising mixing and dissolving a water-soluble polymer (A) and water in a multi-screw extruder to obtain a resin composition (Z), extruding the obtained resin composition (Z) from a nozzle to form a water-soluble film,

[0017] The multi-screw extruder comprises: a plurality of temperature-adjustable barrels and a plurality of screws formed by combining a plurality of screw elements.

[0018] When the temperature-adjustable barrels are C1, C2, C3, etc. from the upstream, the barrel provided with a raw material supply port for supplying a raw material containing the water-soluble polymer (A) as a main component is C S , the barrel provided with the raw material supply port most upstream of the raw material supply ports for supplying the raw material containing water is set as C T , 0≤TS≤6 (where S and T are integers greater than 1, respectively).

[0019] The ratio (L / D) of the effective length (L) of the screw to the diameter (D) of the screw is more than 50 and 100 or less.

[0020] [2] The method for producing a water-soluble film according to [1], wherein the screw has a kneading disc area, and the kneading disc area is set to K1, K2, K3, ..., K4, respectively, from the upstream of the multi-screw extruder. m , (K m The upstream end of the kneading disc area K1 is located at a position lower than that of the barrel C. T Also close to downstream.

[0021] [3] The method for producing a water-soluble film according to [2], comprising a plurality of raw material supply ports for supplying a raw material containing water, wherein the barrel provided with the most downstream raw material supply port is C u When the kneading disk area K m The upstream end of the barrel portion C is located at a position lower than the u Also close to downstream.

[0022] [4] The method for producing a water-soluble film according to [2] or [3], comprising a plurality of raw material supply ports for supplying a raw material containing water, wherein the barrel provided with the most downstream raw material supply port is C u When the kneading disk area K m-1 (wherein m is an integer greater than or equal to 2.) The downstream end is located at a position lower than the aforementioned barrel portion C u Also close to upstream.

[0023] [5] The method for producing a water-soluble film according to any one of [1] to [4], wherein the water-soluble polymer (A) comprises a polyvinyl alcohol-based resin.

[0024] [6] The method for producing a water-soluble film according to any one of [1] to [5], wherein the resin composition (Z) extruded from the nozzle has a water content of 20 to 60% by mass.

[0025] [7] The method for producing a water-soluble film according to any one of [1] to [6], wherein the plasticizer (B) is contained in an amount of 10 to 60 parts by mass based on 100 parts by mass of the water-soluble polymer (A).

[0026] [8] A water-soluble film, characterized in that it is produced by the method for producing a water-soluble film according to any one of [1] to [7].

[0027] [9] A packaging body formed from the water-soluble film described in [8].

[0028]

[10] A medicine package, comprising: a package formed of the water-soluble film according to [8] and a medicine packaged in the package.

[0029] Effects of the Invention

[0030] According to the method for producing a water-soluble film of the present invention, the resin composition does not color, the obtained water-soluble film does not contain undissolved water-soluble polymers, has excellent mechanical properties, and is also excellent in formability, anti-blocking properties, and transparency. In addition, the obtained water-soluble film does not break or leak contents when used for packaging of medicines, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is an explanatory diagram of a multi-screw extruder used in one embodiment of the present invention. DETAILED DESCRIPTION

[0032] Hereinafter, the present invention will be described in more detail based on embodiments of the present invention, but the present invention is not limited to these embodiments.

[0033] It should be noted that, when expressed as "X to Y" (X and Y are arbitrary numbers) in the present invention, unless otherwise specified, it also includes the meaning of "X or more and Y or less", as well as the meaning of "preferably greater than X" or "preferably less than Y".

[0034] Furthermore, when expressed as "X or more" (X is an arbitrary number) or "Y or less" (Y is an arbitrary number), it also includes the meaning of "preferably greater than X" or "preferably less than Y".

[0035] In addition, in the present invention, "x and / or y (x, y are arbitrary structures or components)" means three types of combinations: only x, only y, and x and y.

[0036] The main component refers to the component that accounts for the largest amount in the object, and is usually 50% by mass or more, preferably 60% by mass or more, and particularly preferably 70% by mass or more in the object.

[0037] The present invention is a method for producing a water-soluble film, wherein a resin composition (Z) is extruded from a nozzle to form a film, wherein the resin composition (Z) is obtained by mixing / dissolving a water-soluble polymer (A) and water in a multi-screw extruder and is composed mainly of a mixture of the water-soluble polymer (A) and water.

[0038] <Multi-screw extruder>

[0039] An example of a multi-screw extruder used in the present invention is shown in Figure 1 .

[0040] Figure 1In the embodiment, a multi-screw extruder 1 includes a plurality of screws 3 in a barrel 4 to which a plurality of temperature-adjustable barrels 2 are connected.

[0041] In addition, a head 25 is provided on the downstream side of the multi-screw extruder 1, and a breaker plate 26 may be provided in the flow path of the head 25. In addition, a net for catching foreign matter may be provided on the breaker plate 26.

[0042] Further, a conduit 27, a gear pump 28, a filter assembly, a filter device 29 such as a screenchanger, etc. can be appropriately connected to the downstream side of the head 25. A nozzle 30 is provided at the most downstream. Here, downstream refers to the direction in which the composition flows in the multi-screw extruder 1, and upstream refers to the opposite direction.

[0043] In the present invention, as the multi-screw extruder 1, an extruder having three or more screws may be used in addition to a twin-screw extruder. However, a twin-screw extruder is preferred in terms of equipment introduction cost and maintenance.

[0044] Hereinafter, the configuration of the multi-screw extruder 1 will be described.

[0045] 〔Screw〕

[0046] The screw 3 is composed of a combination of screw elements divided along the effective length direction of the screw. The dimensions of the screw 3 can be expressed by the effective length of the screw (L) (unit: mm) and the screw diameter (D) (unit: mm).

[0047] In the present invention, the ratio (L / D) of the screw effective length (L) (unit: mm) to the screw diameter (D) (unit: mm) exceeds 50 and is 100 or less, preferably 52-95, particularly preferably 55-90, and further preferably 60-85.

[0048] If the above (L / D) is too small, mixing becomes insufficient, undissolved water-soluble polymer (A) is generated, or the steam in the extruder sometimes flows backward. On the other hand, if the above (L / D) is too large, coloring occurs in the film-forming raw material as the mixture, or the anti-blocking property of the obtained film is sometimes reduced.

[0049] Examples of the screw element include a kneading disc element 11 and a full flight element 12 .

[0050] The kneading disc element 11 is a screw element capable of kneading and mixing the raw materials in the extruder. Examples of the kneading disc element 11 include a kneading disc, a rotor, a torsion kneading disc, and a gear kneading device.

[0051] The kneading disk is composed of a plurality of plate-shaped kneading disks whose cross-section is perpendicular to the axial direction of the screw and is formed into a substantially elliptical shape and arranged continuously along the axial direction. The kneading disk rotates as the screw rotates, and the material is introduced between the kneading disk and the inner wall of the barrel to mix the material.

[0052] The kneading disk can adjust the mixing intensity according to the installation method of the kneading disk (the installation angle relative to the screw shaft).

[0053] For example, in the present invention, a conveying kneading disk may be used in which a plurality of kneading disks are continuously installed with a phase difference of 30 to 60 degrees at a predetermined pitch in the reverse rotation direction of the screw.

[0054] Alternatively, a neutral kneading disk in which kneading disks are installed continuously with a phase difference of 90° may be used.

[0055] Furthermore, a return kneading disk may be used in which a plurality of kneading disks are continuously installed at a predetermined pitch of 30 to 60 degrees in phase difference in the direction of rotation of the screw.

[0056] The aforementioned conveying kneading disk is arranged in a manner that the kneading disk is twisted in the axial direction, so it has the ability to convey the material, but the neutral kneading disk has almost no ability to convey the material. Therefore, for the neutral kneading disk, the material stays in the kneading section and is easily fully kneaded, and the kneading degree can be improved compared with the conveying kneading disk. In addition, the return kneading disk has the ability to return the kneaded resin composition (Z) from the downstream to the upstream, so the kneading degree can be further improved.

[0057] The full-thread element 12 is a screw element having a spiral groove and a wing portion (screw flight) forming the groove in a spiral shape.

[0058] The full-screw element 12 rotates so that the composition in the groove of the full-screw element 12 is transported to other screw flight grooves at the meshing portion and extruded downstream.

[0059] The number of spiral ridges (number of spiral ridges) of the aforementioned full-thread element 12 can be one, two, or more than three, but for the sake of efficient conveying, two spiral ridges are preferably used. In addition, there are no special restrictions on the length and spiral ridge spacing of the full-thread element 12. The full-thread elements 12 located before and after the kneading disk area described later are preferably arranged with a shortened spacing to increase the filling rate.

[0060] In the present invention, the screw 3 preferably has a kneading disc region 13 formed by connecting the kneading disc elements 11. By having the kneading disc region 13, the water-soluble polymer (A) and water can be mixed and dissolved more efficiently.

[0061] The number of the kneading disk area 13 may be one or more, but it is preferably more than one.

[0062] When there are multiple kneading disk areas 13, they can be respectively arranged as K1, K2, K3, ..., K4, K5, K6, K7, K8, K9, K10, K11, K2, K3, ..., K12, K13, K14, K15, K16, K17, K18, K19, K20, K21, K30, ..., K41, K52, K19, K10, m (K m The kneading disc area 13 is located at the most downstream side. ) In addition, a full-screw element 12 is arranged between each kneading disc area 13.

[0063] In the present invention, the upstream end of the kneading disk zone K1 is preferably located within 55% of the upstream in the direction of the effective screw length (L), more preferably within 50%, and particularly preferably within 45%.

[0064] The upstream side end of the kneading disk area K1 is in the aforementioned range relative to the upstream distance in the direction of the effective length (L) of the screw, so that in the multi-screw extruder system, strong shearing and kneading can be provided from the beginning, and the water-soluble polymer (A) can be efficiently mixed / dissolved, and there is a tendency that undissolved matter will not remain in the water-soluble film.

[0065] Here, the upstream end of the kneading disk area K1 refers to the position of the upstream end of the kneading disk element 11 that constitutes the kneading disk area K1 and is arranged on the most upstream side.

[0066] The position X% from upstream in the direction of the screw effective length (L) refers to a relative position when the upstream end of the screw element disposed most upstream among all the screw elements constituting the screw 3 is set to 0% and the downstream end of the screw element disposed most downstream is set to 100%.

[0067] In the present invention, the kneading disk area K m The downstream end is preferably located 50% or more from the upstream in the direction of the effective length (L) of the screw, more preferably 55% or more, and particularly preferably 60% or more.

[0068] Kneading disk area K m The downstream side end is located in the aforementioned range relative to the upstream distance in the direction of the effective length (L) of the screw, so that in the system of the multi-screw extruder, strong shearing and kneading can be provided to the small undissolved matter remaining at the end, thereby efficiently mixing / dissolving the water-soluble polymer (A), and there is a tendency that the undissolved matter does not remain in the water-soluble film.

[0069] Here, the kneading disk area K m The downstream end of the kneading disk area K m The kneading disc element is arranged at a downstream end of the kneading disc element on the most downstream side among the kneading disc elements.

[0070] In the present invention, the total length (L KD ) relative to the effective length of the screw (L) KD / L) is preferably 0.15 or more, more preferably 0.17 or more, and further preferably 0.19 or more. The upper limit is usually 0.90 or less, preferably 0.80 or less, and more preferably 0.75 or less.

[0071] The total length (L KD ) means that the above K1, K2, K3, ..., K m The total axial length of KD / L) is within the above range, thereby ensuring time for providing strong shearing and kneading in the multi-screw extruder, and there is a tendency that mixing / dissolving of the water-soluble polymer (A) can be performed efficiently.

[0072] In addition, the kneading disc area 13 preferably has a certain length. Specifically, the axial length of the kneading disc area 13 is preferably 2% or more, more preferably 3% or more, and further preferably 4% or more relative to the effective length (L) of the screw. In addition, it is preferably 90% or less, more preferably 80% or less, and further preferably 70% or less. When there are multiple kneading disc areas 13, it is preferred that each kneading disc area 13 is within the above range.

[0073] When the axial length of the kneading disk zone 13 is within the above range, the resin composition tends to stay in the kneading section, and the water-soluble polymer (A) tends to be easily dissolved.

[0074] 〔Barrel〕

[0075] The barrel 4 is connected to a plurality of temperature-adjustable barrels 2 as described above, and has at least two raw material supply ports, one for supplying a raw material containing a water-soluble polymer (A) as a main component and one for supplying a raw material containing water.

[0076] In addition, in the present invention, it is also preferred to have multiple raw material supply ports for supplying raw materials containing water. By having multiple aforementioned raw material supply ports for supplying raw materials containing water, the water content of the resin composition (Z) extruded from the nozzle can be adjusted. In addition, after the water-soluble polymer (A) is mixed / dissolved in water, various additives described later, such as plasticizer (B), filler (C), surfactant (D), etc. are dissolved in water and supplied to a multi-screw extruder, so that thermal history and shear can be reduced. Therefore, when adding additives that are relatively weak, easily decomposed, and dissolved with heat and shear, it becomes effective.

[0077] The upstream side of the barrel 4 is provided with a raw material supply port 21. In addition, a plurality of raw material supply ports, such as a raw material supply port 22 and a raw material supply port 23, may be provided in the barrel 4 downstream of the raw material supply port 21.

[0078] The raw material supply port 22 can supply liquid from a liquid adding pump 32 connected to a liquid tank 31. In addition, in the raw material supply port 23, liquid can be supplied from a liquid adding pump 32 connected to a liquid tank 31, or a solid can be supplied to the multi-screw extruder 1 using a feeder 33 (including a side feeder).

[0079] In addition, the screw element used in the barrel 2 provided with a raw material supply port for supplying a raw material containing water can use any of the kneading disk element 11 and the full-screw element 12, but in order to suppress the overflow of water in the supply part and the backflow to the upstream, it is preferred to use the full-screw element 12.

[0080] Furthermore, it is preferred that the fully threaded element 12 is formed between the raw material supply port for supplying the raw material mainly composed of the water-soluble polymer (A) and the raw material supply port disposed most upstream of the raw material supply port for supplying the raw material containing water.

[0081] As mentioned above, the barrel 4 is connected to the temperature-adjustable barrel 2. When the temperature-adjustable barrel 2 is respectively set as C1, C2, C3, etc. from the upstream, the barrel 2 provided with the raw material supply port for supplying the raw material containing the water-soluble polymer (A) as the main component is set as C1, C2, C3, etc. S , the barrel 2 provided with the raw material supply port most upstream of the raw material supply ports for supplying the raw material containing water is set as C T When TS is 0≤TS≤6 (wherein S and T are each an integer greater than or equal to 1), 1≤TS≤5 is preferred, and 1≤TS≤4 is particularly preferred.

[0082] When TS≧7, the thermal history to which the water-soluble polymer (A) is subjected increases, and the obtained resin composition (Z) is colored yellow.

[0083] In addition, since the region in which the water-soluble polymer (A) is conveyed in the barrel 4 without being plasticized by water becomes longer, the load and shear heat generation of the multi-screw extruder 1 become larger, the multi-screw extruder 1 becomes more likely to stop, and the coloring of the resin composition (Z) is promoted.

[0084] In addition, when there are multiple raw material supply ports for supplying raw materials with a water-soluble polymer (A) as the main component, the positional relationship between the barrel 2 provided with the most upstream raw material supply port and the barrel 2 provided with the most upstream raw material supply port among the raw material supply ports for supplying raw materials containing water is within the above-mentioned range.

[0085] In the present invention, the raw material supply port 21 is preferably used to supply a raw material mainly composed of a water-soluble polymer (A), and the raw material supply ports 22 and 23 are preferably used to supply a raw material containing water. The raw material supply port 21 is preferably provided in the cylinder C1.

[0086] When there are a plurality of raw material supply ports for supplying the raw material containing water, it is preferred that the barrel provided with the raw material supply port at the most downstream is set as C u When the kneading disk area K m The upstream end of the barrel C is located at a position u Also close to downstream.

[0087] By making K m The upstream end of the barrel C is located at a position u Also close to the downstream, so that the barrel portion C u The added water and additives are uniformly dispersed in the resin composition (Z).

[0088] In addition, when there are a plurality of raw material supply ports for supplying the raw material containing water, it is preferred that the barrel provided with the raw material supply port at the most downstream is set as C u When the kneading disk area K m-1 (wherein m is an integer greater than or equal to 2.) The downstream end is located at a position lower than the aforementioned barrel C u Also close to upstream.

[0089] In this regard, as mentioned above, the screw element of the water supply part is preferably a full-screw element 12, u The encapsulation contains the aforementioned kneading disk area K m-1 When it is at the downstream end, it is easy to cause the water in the supply part to overflow and flow back upstream, so it is not preferred.

[0090] Furthermore, the barrel 2 may also be provided with a vent hole 24. In the present invention, it is preferred to have a vent hole 24 to degas volatile components and gases such as moisture generated in the extruder. The vent hole 24 can be used to degas the steam generated in the barrel 4, or to be connected to a vacuum pump for vacuuming. In addition, as required, the raw material supply port and the vent hole can be more Figure 1 The number of records has further increased.

[0091] <Resin composition (Z)>

[0092] As described above, the present invention is a method for producing a water-soluble film, wherein a resin composition (Z) is obtained by mixing / dissolving a water-soluble polymer (A) and water in a multi-screw extruder and is mainly composed of a mixture of the water-soluble polymer (A) and water, and is extruded from a nozzle to form a film. Hereinafter, each component contained in the resin composition (Z) is described.

[0093] 〔Water-soluble polymer (A)〕

[0094] Examples of the water-soluble polymer (A) include polyvinyl alcohol resins, polyethylene glycol resins, carboxymethyl cellulose resins, sodium acrylate resins, polyvinyl pyrrolidone, dextrin, chitosan, chitin, methyl cellulose, hydroxyethyl cellulose, casein, pullulan, etc. The water-soluble polymer (A) may be used alone or in combination of two or more.

[0095] Among them, polyvinyl alcohol-based resins are preferably contained.

[0096] 〔Polyvinyl alcohol resin〕

[0097] In the present invention, polyvinyl alcohol (hereinafter referred to as "PVA") resin refers to a resin having vinyl alcohol unit as the main unit component in the repeating unit constituting the polymer. The main unit component refers to a unit component that accounts for 50 mol% or more and 100 mol% or less in the resin. PVA resin is a thermoplastic resin and a water-soluble resin. Films made of PVA resin as the main component are also used as water-soluble films and are used in a wide range of fields.

[0098] Examples of the PVA-based resin used in the present invention include unmodified PVA and modified PVA-based resins.

[0099] The average saponification degree of the PVA resin used in the present invention is preferably 80 mol% or more, particularly preferably 82 to 99.9 mol%, further preferably 85 to 98.5 mol%, and particularly preferably 90 to 97 mol%. In addition, when unmodified PVA is used as the PVA resin, the average saponification degree is preferably 80 mol% or more, particularly preferably 82 to 99 mol%, and further preferably 85 to 90 mol%. Furthermore, when a modified PVA resin is used as the PVA resin, the average saponification degree is preferably 80 mol% or more, particularly preferably 85 to 99.9 mol%, and further preferably 90 to 98 mol%. Furthermore, when an anionic group-modified PVA resin is used as the PVA resin, the average saponification degree is preferably 85 mol% or more, particularly preferably 88 to 99 mol%, further preferably 90 to 97 mol%, and particularly preferably 91 to 94 mol%. If the above average saponification degree is too low, the solubility of the water-soluble film in water tends to decrease over time depending on the pH of the drug to be packaged. It should be noted that if the average saponification degree is too large, the solubility in water tends to be significantly reduced.

[0100] In addition, the degree of polymerization of the PVA resin used in the present invention can be generally expressed by the viscosity of the aqueous solution, and the viscosity of the 4 mass % aqueous solution at 20°C is preferably 5 to 50 mPa·s, more preferably 13 to 45 mPa·s, and particularly preferably 17 to 40 mPa·s. In addition, when unmodified PVA is used as the PVA resin, the viscosity of the 4 mass % aqueous solution of the unmodified PVA at 20°C is preferably 5 to 50 mPa·s, more preferably 13 to 45 mPa·s, and particularly preferably 17 to 40 mPa·s. In addition, when a modified PVA resin is used as the PVA resin, the viscosity of the 4 mass % aqueous solution of the modified PVA resin at 20°C is preferably 5 to 50 mPa·s, more preferably 13 to 40 mPa·s, and particularly preferably 17 to 30 mPa·s. If the above viscosity is too low, the mechanical strength of the water-soluble film as a packaging material tends to be reduced, while if it is too high, the viscosity of the film-forming raw material tends to be high and the productivity tends to be reduced.

[0101] In addition, the said average saponification degree is measured according to JIS K 6726 3.5, and the viscosity of 4 mass % aqueous solution is measured according to JIS K 6726 3.11.2.

[0102] When a modified PVA resin is used as the PVA resin, the modification amount is preferably 1 to 10 mol%, more preferably 1.5 to 8 mol%, particularly preferably 2 to 6 mol%, and particularly preferably 2 to 5 mol%. If the modification amount is too small, the solubility in water tends to decrease, and if it is too large, the productivity of the PVA resin tends to decrease, the biodegradability tends to decrease, and there is a tendency to become easy to cause blocking.

[0103] In the present invention, the above-mentioned PVA-based resins may be used alone, or unmodified PVA and modified PVA-based resins may be used in combination. Furthermore, two or more types having different saponification degrees, viscosities, modification types, modification amounts, etc. may be used in combination.

[0104] Among them, in the water-soluble film for drug packaging (especially for detergent packaging), in terms of solubility, the PVA-based resin preferably contains a modified PVA-based resin, and particularly preferably contains an anionic group-modified PVA-based resin. As the type of anionic group, for example, carboxyl, sulfonic acid, phosphoric acid, etc. can be cited. In terms of solubility in water and drug resistance, carboxyl and sulfonic acid groups are preferred, and carboxyl groups are particularly preferred.

[0105] The carboxyl group of the carboxyl-modified PVA is derived from a monomer having a carboxyl group, for example, acrylic acid, methacrylic acid, crotonic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid and other carboxyl-containing unsaturated compounds, and their carboxyl groups are neutralized as a whole or in part by alkali compounds (such as sodium hydroxide, potassium hydroxide, etc.), or methyl acrylate, ethyl acrylate, methyl methacrylate, monomethyl fumarate, monomethyl maleate and other monoalkyl esters of the above-mentioned carboxyl-containing unsaturated compounds, diethyl fumarate, diethyl maleate and other dialkyl esters of the above-mentioned carboxyl-containing unsaturated compounds. For the carbon number of these esters, from the aspects of economy and practicality, it is usually 1 to 20 carbon numbers, more preferably 1 to 10 carbon numbers, and particularly preferably 1 to 4 carbon numbers. Among these, maleic acid compounds are preferred, and monomethyl maleate is further preferred.

[0106] The PVA-based resin can be produced by a conventionally known method such as that described in Japanese Patent Application Laid-Open No. 2017-95679, etc.

[0107] 〔water〕

[0108] The water used in the present invention is not particularly limited, but ion exchange water or RO water is preferably used.

[0109] As the water, preferably, water having a silicon dioxide content of 50 μg / L or less, preferably 5.0 μg / L or less, and a chloride ion content of 2 μg / L or less, preferably 1 μg / L.

[0110] In the present invention, the resin composition (Z) may contain a plasticizer (B), a filler (C), a surfactant (D), and other additives.

[0111] 〔Plasticizer (B)〕

[0112] In the present invention, in order to impart appropriate softness to the film, it is preferred to contain a plasticizer (B). The plasticizer (B) may be used alone or in combination of two or more. From the perspective of the mechanical properties and formability of the film, it is also preferred to use two or more of them in combination.

[0113] As the above-mentioned plasticizer (B), for example, glycerols such as glycerol, diglycerol, and triglycerol, alkylene glycols such as diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, and dipropylene glycol, trimethylolpropane, sorbitol, xylitol, and maltitol, etc. can be cited. Among them, glycerol, diglycerol, and polyethylene glycol are preferred in terms of easy availability and plasticizing effect in small amounts, and sorbitol is preferably used in terms of the stability of the package over time. These can be used alone or in combination of two or more.

[0114] When two or more of the above plasticizers are used in combination, it is preferred to use in combination a polyol (b1) having a melting point of 80°C or higher (hereinafter, sometimes referred to as "plasticizer (b1)") and a polyol (b2) having a melting point of 50°C or lower (hereinafter, sometimes referred to as "plasticizer (b2)"). Furthermore, as the above plasticizer (b2), a compound that is liquid at room temperature is preferred in terms of productivity and mechanical properties of the obtained film, and the melting point is preferably 30°C or lower, particularly preferably 20°C or lower. It should be noted that the lower limit of the melting point is usually -95°C, preferably -40°C, particularly preferably -15°C, and further preferably -5°C.

[0115] The content of the plasticizer (B) is preferably 10 to 60 parts by mass, particularly preferably 15 to 55 parts by mass, and further preferably 20 to 50 parts by mass, relative to 100 parts by mass of the water-soluble polymer (A). If the content of the plasticizer (B) is too small, there is a tendency that the plasticizing effect is low and the processability is reduced, or when a package is formed, there is a tendency that the toughness of the water-soluble film is destroyed over time, and if it is too large, there is a tendency that the strength of the film is reduced or it becomes easy to cause blocking.

[0116] 〔Packing (C)〕

[0117] In the present invention, a filler (C) may be further contained as necessary.

[0118] The filler (C) is contained for the purpose of anti-blocking, and examples thereof include organic fillers (c1) and inorganic fillers (c2). Among them, the organic filler (c1) is preferably contained.

[0119] The average particle size of the filler (C) is preferably 0.1 to 50 μm, particularly preferably 1 to 35 μm. It should be noted that the average particle size of the filler (C) is a value measured by a laser diffraction particle size distribution measuring device and is calculated based on the D50 value (particle size at cumulative 50%) of the obtained cumulative volume distribution.

[0120] The organic filler (c1) refers to a granular substance (primary particle) composed of an organic compound and having any shape such as needles, rods, layers, scales, or spheres, or an aggregate of the granular substances (secondary particles).

[0121] The organic filler (c1) is mainly selected from polymer compounds, for example, in addition to melamine resins, poly(methyl)acrylate resins, polystyrene resins, biodegradable resins such as starch and polylactic acid, etc. Among them, biodegradable resins such as poly(methyl)acrylate resins, polystyrene resins, and starch are preferred, and starch is particularly preferred from the perspective of dispersibility in the water-soluble polymer (A).

[0122] Examples of the starch include raw starch (corn starch, potato starch, sweet potato starch, wheat starch, cassava starch, sago starch, tapioca starch, sorghum starch, rice starch, bean starch, kudzu starch, bracken starch, lotus root starch, water chestnut starch, etc.), physically modified starch (α-starch, fractionated amylose, moisture-heat treated starch, etc.), enzyme-modified starch (hydrolyzed dextrin, enzyme-degraded dextrin, amylose, etc.), chemically degraded modified starch (acid-treated starch, hypochlorous acid-oxidized starch, dialdehyde starch, etc.), chemically modified starch derivatives (esterified starch, etherified starch, cationized starch, cross-linked starch, etc.), etc. Among them, raw starch, particularly corn starch and rice starch, are preferably used from the aspects of biodegradability, ease of availability, and economic efficiency.

[0123] The average particle size of the organic filler (c1) is preferably 5 to 50 μm, particularly preferably 10 to 40 μm, and further preferably 15 to 35 μm. If the average particle size is too small, the blocking property of the film tends to increase, while if it is too large, the fillers tend to aggregate with each other, the dispersibility tends to decrease, or pinholes tend to form during film forming and stretching.

[0124] As the inorganic filler (c2), an oxide-based inorganic compound or talc is preferably used, titanium oxide, talc, or silica is particularly preferably used, and silica is further preferably used.

[0125] The average particle size of the inorganic filler (c2) is preferably 1 to 20 μm, particularly preferably 2 to 15 μm, and further preferably 3 to 10 μm. If the average particle size is too small, the softness and toughness of the film tend to decrease, or the blocking property tends to increase. If the average particle size is too large, the film tends to form pinholes during stretching during film molding.

[0126] The content of the filler (C) is preferably 1 to 30 parts by mass, particularly preferably 1.5 to 25 parts by mass, and further preferably 2 to 20 parts by mass, relative to 100 parts by mass of the water-soluble polymer (A). If the content is too low, the stickiness of the film tends to increase, while if it is too high, the softness and toughness of the film tend to decrease.

[0127] 〔Surfactant (D)〕

[0128] In the present invention, a surfactant (D) or the like may be further contained as necessary.

[0129] The surfactant (D) used in the present invention is contained for the purpose of improving the peelability of the self-casting surface when manufacturing the film, and nonionic surfactants, cationic surfactants, and anionic surfactants can be generally cited. For example, polyoxyethylene nonylphenyl ether, polyoxyethylene octyl nonyl ether, polyoxyethylene dodecylphenyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate, polyoxyethylene alkyl ether phosphate monoethanolamine salt, polyoxyethylene lauryl amino ether, polyoxyethylene stearyl amino ether, polyoxyethylene alkyl amino ethers such as sorbitan monopalmitate, sorbitan monostearate, stearic acid glyceryl, sucrose fatty acid ester, etc. can be cited, and they can be used alone or in combination of two or more. Among them, polyoxyethylene alkyl ether phosphate monoethanolamine salt and polyoxyethylene lauryl amino ether are suitable in terms of manufacturing stability.

[0130] The above surfactant (D) may be used alone or in combination of two or more.

[0131] The content of the surfactant (D) is preferably 0.01 to 3 parts by mass, particularly preferably 0.05 to 2.5 parts by mass, and further preferably 0.1 to 2 parts by mass relative to 100 parts by mass of the water-soluble polymer (A). If the content is too low, the peelability between the casting surface of the film-forming device and the film to be formed tends to decrease, thereby reducing productivity. If the content is too high, the film tends to become easily blocked, or the adhesive strength when the film is used to form a package tends to decrease.

[0132] It should be noted that the resin composition (Z) may contain solvents, fragrances, rust inhibitors, colorants, extenders, defoamers, ultraviolet absorbers, liquid paraffins, fluorescent whitening agents, bitter ingredients (such as denatonium benzoate, etc.), etc., within the range not hindering the purpose of the invention. These may be used alone or in combination of two or more.

[0133] Examples of the solvent include ethanol, methanol, propanol, isopropanol, acetone, methyl ethyl ketone, acetic acid, methyl acetate, ethyl acetate, butyl acetate, benzene, toluene, etc. The solvents may be used alone or in combination of two or more.

[0134] In addition, in the present invention, an antioxidant may be blended. Examples of the antioxidant include sulfites such as sodium sulfite, potassium sulfite, calcium sulfite, and ammonium sulfite, tartaric acid, ascorbic acid, sodium thiosulfate, catechol, and Rongalite. Among them, sulfites are preferred, and sodium sulfite is particularly preferred. The blending amount is preferably 0.1 to 10 parts by mass, particularly preferably 0.2 to 5 parts by mass, and further preferably 0.3 to 3 parts by mass relative to 100 parts by mass of the water-soluble polymer (A).

[0135] <Method for producing water-soluble film>

[0136] Next, the method for producing the water-soluble film of the present invention will be described.

[0137] The production method of the present invention preferably includes at least the following steps.

[0138] Step [I]: A step of supplying a raw material containing a water-soluble polymer (A) as a main component to a multi-screw extruder

[0139] Step [II]: a step of supplying a raw material containing water from at least one point of the multi-screw extruder

[0140] Step [III]: a step of mixing and dissolving the raw materials in a multi-screw extruder to prepare a resin composition (Z)

[0141] Step [IV]: a step of extruding the resin composition (Z) from a nozzle onto a casting surface to form a water-soluble film

[0142] [Step [I]: a step of supplying a raw material containing a water-soluble polymer (A) as a main component to a multi-screw extruder]

[0143] As a method for supplying the raw material containing the water-soluble polymer (A) as a main component, for example, from the Figure 1The method of supplying the raw material is shown in the raw material supply port of the barrel 2 of the multi-screw extruder 1. The raw material supply port for supplying the raw material containing the water-soluble polymer (A) as a main component to the multi-screw extruder may be one or two or more.

[0144] In the present invention, from the viewpoint of production efficiency, it is preferred to supply a raw material containing a water-soluble polymer (A) as a main component from the raw material supply port 21 located most upstream among the plurality of raw material supply ports provided. It is also preferred to supply a raw material containing a portion of the water-soluble polymer (A) as a main component from the raw material supply port 21 located most upstream among the plurality of raw material supply ports provided, dissolve the remaining water-soluble polymer (A) in water, and supply the raw material as a raw material containing water described later.

[0145] The form of the water-soluble polymer (A) supplied is not particularly limited, and may be, for example, powder, granules, pellets, or the like.

[0146] Furthermore, the raw material containing the water-soluble polymer (A) as a main component may contain a plasticizer (B), a filler (C), a surfactant (D), other additives, and a solvent.

[0147] [Step [II]: a step of supplying a raw material containing water from at least one point of the multi-screw extruder]

[0148] Next, the step of supplying a raw material including water from at least one location of the multi-screw extruder 1 will be described.

[0149] The raw material containing water may contain, in addition to water, a water-soluble polymer (A), a plasticizer (B), a filler (C), a surfactant (D), other additives, and a solvent.

[0150] Among them, it is preferred that the raw material containing water contains a plasticizer (B), a filler (C), and a surfactant (D).

[0151] The raw material containing water is supplied from a barrel C provided with a raw material supply port for supplying a raw material containing a water-soluble polymer (A) as a main component. S The barrel C is provided with a raw material supply port at the most upstream of the raw material supply ports for supplying a raw material containing water. T The positional relationship becomes the raw material supply port supply within a specific range.

[0152] In addition, the method for supplying the raw material including water is not particularly limited, and for example, the raw material may be supplied using a liquid adding pump 32 or the like.

[0153] The temperature of the barrel 2 provided with the raw material supply port is preferably 15 to 105° C., more preferably 20 to 100° C., and further preferably 25 to 95° C. When the barrel temperature is lower than 15° C., a large amount of energy is consumed when heating the mixture on the downstream side, and productivity tends to decrease. In addition, when the barrel temperature exceeds 105° C., steam returns to the upstream side, steam rises from the supply port of the water-soluble polymer (A), and the water-soluble polymer (A) is adhered, and productivity tends to decrease.

[0154] When the aforementioned plasticizer (B), filler (C), surfactant (D), other additives, and solvent are not mixed with the raw material containing the water-soluble polymer (A) as the main component or the raw material containing water, these raw materials can be independently supplied from the raw material supply port to the multi-screw extruder 1 using, for example, a water adding pump 32, a feeder, a side feeder 33, etc. In this case, it is preferable to supply them downstream of the raw material containing water.

[0155] When the filler (C) is contained, it may be blended in the raw material containing the water-soluble polymer (A) as a main component or the raw material containing water as described above, but it is also preferably dispersed in the plasticizer (B) and blended in view of dispersibility.

[0156] In addition, when the filler (C) is supplied to the multi-screw extruder 1, its supply position is preferably located at a position 50% or more from the upstream of the screw, more preferably at a position 60% or more, further preferably, particularly preferably at a position 70% or more, and further preferably at a position 75% or more.

[0157] By supplying the filler (C) to the multi-screw extruder 1 at a position 50% or more upstream of the screw, the filler (C) tends to be contained in the film in a size that can provide the irregularities required for maintaining anti-blocking properties.

[0158] In particular, when an organic filler (c1) is used as the filler (C), it is preferred in that a film excellent in anti-blocking property and water-tightness can be obtained.

[0159] [Step [III]: a step of mixing and dissolving the raw materials in a multi-screw extruder to prepare a resin composition (Z)]

[0160] The step of mixing and dissolving the raw materials in the multi-screw extruder 1 to prepare the resin composition (Z) is performed by rotating the screw 3 provided inside the barrel 4 of the multi-screw extruder 1 .

[0161] In this step, the water-soluble polymer (A) is dissolved in water to prepare a resin composition (Z) as a mixture (film-forming raw material).

[0162] The rotation speed of the screw 3 is usually 50 to 1000 rpm, preferably 100 to 800 rpm, and more preferably 150 to 600 rpm.

[0163] If the rotation speed of the screw 3 is too low, the discharge tends to become unstable, and if it is too high, the obtained film may be colored.

[0164] In addition, in order to obtain sufficient kneading by appropriate shearing, it is preferred that the screws rotate in the same direction.

[0165] The temperature of each cylinder 2 is preferably 10 to 170°C, more preferably 30 to 150°C, particularly preferably 40 to 130°C, and particularly preferably 50 to 110°C.

[0166] If the temperature is too low, mixing and dissolution become insufficient, and there is a tendency for undissolved water-soluble polymer (A) or bubbles to remain. On the other hand, if the temperature is too high, the mixture is colored, the transparency of the obtained film is reduced, or the anti-blocking property tends to deteriorate.

[0167] In the present invention, the water content of the resin composition (Z) in the multi-screw extruder is preferably 20 to 60% by mass, more preferably 25 to 55% by mass, and even more preferably 30 to 50% by mass.

[0168] If the water content is too low, the water-soluble polymer may not be fully dissolved, undissolved matter may remain, the viscosity of the film-forming raw material may increase, degassing may be insufficient, or parting lines may be produced during film formation. If the water content is too high, the accuracy of the film thickness may decrease, the drying efficiency may decrease during film formation, and the productivity of the water-soluble film may decrease.

[0169] In the present invention, the pH of the resin composition (Z) in the multi-screw extruder is preferably 4 to 10, more preferably 4.8 to 9.5.

[0170] [Step [IV]: a step of extruding the resin composition (Z) from a nozzle onto a casting surface to form a water-soluble film]

[0171] In step [IV], the resin composition (Z) prepared in step [III] is extruded from the nozzle 30 onto the casting surface and formed into a film shape, and is dried as required to form a water-soluble film.

[0172] As the type of the nozzle 30, a conventionally known nozzle can be used, preferably a T-type slit die. In addition, it is preferred to connect a gear pump 28 between the multi-screw extruder and the nozzle 30. By using the gear pump 28, the thickness distribution of the film in the flow direction becomes easy to be uniform, so it is preferred.

[0173] The temperature of the resin composition (Z) in the discharge section of the T-slit die or the like is preferably 60 to 98° C., particularly preferably 70 to 95° C. If the temperature is too low, the viscosity of the film-forming raw material increases, and the productivity of the water-soluble film tends to decrease, while if the temperature is too high, bubbles tend to be generated.

[0174] In the present invention, the water content of the resin composition (Z) extruded from the nozzle 30 is preferably 20 to 60% by mass, more preferably 25 to 55% by mass, and even more preferably 30 to 50% by mass.

[0175] The water content is as follows: the resin composition (Z) is recovered immediately after being extruded from a nozzle, and the water content is measured in accordance with JIS K 67263.4, and the value of the volatile components of the recovered product is defined as the water content.

[0176] In addition, the resin composition (Z) extruded from the nozzle 30 is preferably dried on a casting surface such as an endless belt, a metal surface of a roller, or a surface of a plastic substrate such as a polyethylene terephthalate film after being extruded onto the casting surface.

[0177] During drying, the casting surface is usually heated. The surface temperature of the casting surface is preferably 50 to 150° C., particularly preferably 60 to 140° C. If the surface temperature is too low, the moisture content of the film increases due to insufficient drying, and there is a tendency to become easily blocked. If the surface temperature is too high, the resin composition (Z) foams, and there is a tendency to cause poor film formation.

[0178] In addition, in the drying during film formation, drying with a hot roll, drying using a floating dryer to blow hot air to the film, drying with a far infrared device or an induction heating device, etc. may be used in combination.

[0179] The formed water-soluble film is peeled off from the casting surface, etc., transported and wound on a core tube to form a film roll. The obtained film roll can be supplied directly as a product, but it is also preferably supplied as a film roll obtained by slitting the water-soluble film into a film width of a desired size.

[0180] From the perspectives of anti-blocking, slip during processing, reducing adhesion between products and appearance, the water-soluble film may be subjected to embossing, fine embossing, special engraving or the like on one or both sides of the film.

[0181] <Water-soluble film>

[0182] The water-soluble film of the present invention contains a water-soluble polymer (A) as a main component and is a film that dissolves in water at room temperature (20° C.). Furthermore, the water-soluble film is obtained by the characteristic production method of the present invention, and therefore, there is no undissolved matter of the water-soluble polymer (A), and the mechanical properties, moldability, anti-blocking properties, etc. are excellent.

[0183] The thickness of the water-soluble film is appropriately selected according to the application, and is preferably 10 to 120 μm, particularly preferably 15 to 110 μm, and further preferably 20 to 100 μm. If the thickness is too thin, the mechanical strength of the film tends to decrease, and if it is too thick, the dissolution rate in water tends to slow down, and the film-forming efficiency tends to decrease.

[0184] The width of the water-soluble film is appropriately selected according to the application, and is preferably 300 to 5000 mm, particularly preferably 500 to 4000 mm, and further preferably 600 to 3000 mm. If the width is too narrow, the production efficiency tends to decrease, and if it is too wide, the film tends to sag and control of the film thickness becomes difficult.

[0185] The length of the water-soluble film is appropriately selected according to the application, and is preferably 100 to 20,000 m, particularly preferably 800 to 15,000 m, and further preferably 1,000 to 10,000 m. If the length is too short, the replacement of the film requires time and effort, which tends to reduce production efficiency, while if it is too long, tight winding tends to cause poor appearance.

[0186] In addition, in terms of mechanical strength and heat sealability, the water content of the obtained water-soluble film is preferably 3 to 15% by mass, particularly preferably 5 to 9% by mass, and further preferably 6 to 8% by mass. If the above water content is too low, the film becomes too hard, and there is a tendency that the formability when forming a package and the impact resistance of the package are reduced. If it is too high, there is a tendency that it becomes easy to cause blocking. When adjusting the above water content, it can be achieved by appropriately setting the drying conditions and humidity adjustment conditions.

[0187] The water content is measured in accordance with JIS K 6726 3.4, and the value of the volatile matter obtained is defined as the water content.

[0188] The surface roughness (Ra) of the obtained water-soluble film is preferably 0.2 to 1.0 μm, particularly preferably 0.25 to 0.8 μm, and further preferably 0.3 to 0.6 μm.

[0189] If the surface roughness is too small, the anti-blocking property tends to be reduced, and if it is too large, the sealing property tends to be reduced.

[0190] The maximum height difference (Rz) is preferably 2 to 10 μm, particularly preferably 3 to 8 μm, and further preferably 4 to 7 μm.

[0191] In addition, the said surface roughness (Ra) and (Rz) can be measured using a laser microscope based on JIS B0601-2001.

[0192] The water-soluble film of the present invention may be used as a single layer, or may be used as a multilayer structure in which another film or a resin layer is laminated.

[0193] <Packaging and pharmaceutical packaging>

[0194] A packaging body as one embodiment of the present invention is formed by the obtained water-soluble film. In addition, a medicine packaging body as one embodiment of the present invention is a packaging body in which a medicine is encapsulated with the obtained water-soluble film. According to the medicine packaging body, the medicine is packaged with the water-soluble film, so when the medicine is put into water together with the packaging body, after the water-soluble film dissolves, the medicine dissolves or disperses in the water, and the effect of the medicine is manifested. Therefore, it is suitable for a medicine packaging body that packages a relatively small amount of medicine such as a single dose.

[0195] As the medicament to be encapsulated, for example, pesticides such as insecticides, fungicides, herbicides, fertilizers, detergents, etc. can be cited, and detergents such as detergents for washing and detergents for washing dishes are particularly preferred. The shape of the medicament can be liquid or solid. In the case of liquid, it is liquid. In the case of solid, granular, tablet, powder, etc. can be cited. The medicament is preferably dissolved or dispersed in water and used. In the present invention, encapsulated liquid detergents are particularly preferred. In addition, the pH of the medicament can be alkaline, neutral, or acidic.

[0196] The pH value of the liquid detergent when dissolved or dispersed in water is preferably 6 to 12, particularly preferably 6.5 to 11, and particularly preferably 7 to 8. The water content of the liquid detergent is preferably 15% by mass or less, particularly preferably 0.1 to 10% by mass, and further preferably 0.1 to 7% by mass, so that the water-soluble film does not gel or become insoluble, and has excellent water solubility.

[0197] The pH value is measured in accordance with JIS K 3362 8.3. The water content is measured in accordance with JIS K 3362 7.21.3.

[0198] When a drug such as a liquid lotion is packaged with the water-soluble film of the present invention to form a drug package, a known method can be used.

[0199] For example, two water-soluble films are laminated to produce a package. A film (bottle film) is fixed to a mold located at the bottom of a molding device, and a film (top film) is also fixed to the top of the device. After that, a liquid lotion or other drug is added to the molded film, and the top film and the bottle film are pressed together. After the vacuum is released after the pressing, a package can be obtained.

[0200] As a method for crimping the film after the drug is added, for example, there can be cited (1) a heat sealing method, (2) a water sealing method, (3) a glue sealing method, etc. Among them, the above-mentioned (2) water sealing method is universal and advantageous.

[0201] Example

[0202] Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples unless the gist of the present invention is exceeded.

[0203] It should be noted that, in the examples, "parts" refer to mass standards.

[0204] As material components of the water-soluble film, the following substances were prepared.

[0205] 〔Water-soluble polymer (A)〕

[0206] PVA resin (a1): a carboxyl-modified PVA resin having a 4% aqueous solution viscosity of 24 mPa·s at 20°C, an average saponification degree of 94 mol%, and a modification amount of 2.0 mol% with monomethyl maleate

[0207] 〔water〕

[0208] Ion exchange water

[0209] 〔Plasticizer (B)〕

[0210] Plasticizer (b1): Sorbitol

[0211] Plasticizer (b2): glycerol

[0212] 〔Packing (C)〕

[0213] Organic filler (c1): corn starch

[0214] 〔Surfactant (D)〕

[0215] Surfactant (d1): Phosphate ester surfactant

[0216] <Example 1>

[0217] The barrel (C1, C2, C3, ..., C 15) is provided at the front end on the downstream side of the twin-screw extruder, with a head, a conduit and a T-die head.

[0218] At this time, the screw is configured as follows: the kneading disk area K1 is arranged at a position 45 to 51% of the upstream distance relative to the effective length direction of the screw, the kneading disk area K2 is arranged at a position 54 to 60% of the upstream distance, the kneading disk area K3 is arranged at a position 63 to 69% of the upstream distance, the kneading disk area K4 is arranged at a position 72 to 78% of the upstream distance, and the kneading disk area K5 is arranged at a position 81 to 87% of the upstream distance. The ratio (L / D) of the effective length (L) of the screw to the screw diameter (D) is 52.5, and the total length (L) of each kneading disk area is 52.5. KD ) ratio (L KD / L) is 0.30.

[0219] Furthermore, raw material supply ports are provided in barrels C1 and C2. It should be noted that the position of barrel C1 is 1 to 8% upstream in the effective length direction of the screw, and the position of barrel C2 is 8 to 14% upstream.

[0220] A raw material prepared by mixing 20 parts of a plasticizer (b2), 8 parts of a filler (c1) and 1 part of a surfactant (d1) with 100 parts of a PVA-based resin (a1) was supplied to the feeder from the raw material supply port of the cylinder C1.

[0221] Separately, an aqueous solution of a plasticizer (b1) having a concentration of 24% by mass was prepared, and the aqueous solution was added from the raw material supply port of C2 using a liquid adding pump.

[0222] At this time, the feed amount and the pumping liquid amount are adjusted and supplied separately in such a manner that the PVA-based resin (a1) / plasticizer (b1) / plasticizer (b2) / filler (c1) / surfactant (d1) / water = 40.5 mass % / 8.1 mass % / 8.1 mass % / 3.3 mass % / 0.4 mass % / 39.6 mass %.

[0223] In addition, the feeder part of the PVA-based resin (a1), the tank of the aqueous solution, and the pump part were set at room temperature.

[0224] C1~C 15 The set temperature (T1~T 15 ) are set as T1 = 30 ° C, T2 = 30 ° C, T3 ~ T 15 = 90°C, the head, duct, and T-die were set to 90°C, and extrusion was performed to obtain a film-like resin composition from the nozzle.

[0225] The moisture content of the resin composition extruded from the nozzle is 40% by mass. Afterwards, the film-like resin composition extruded from the nozzle is collected on a cooling roll to obtain a water-soluble film of thickness 100 μm. The appearance of the obtained water-soluble film is visually confirmed, and a white transparent film is obtained as a result, and no undissolved matter is confirmed. In addition, any part of the obtained water-soluble film is observed with a digital microscope (200 times), and the result confirms a filler with a size that can maintain anti-blocking properties.

[0226] <Example 2>

[0227] Except that a 24 mass % concentration of a plasticizer (b1) aqueous solution was added from the raw material supply port provided in barrel C4 instead of barrel C2 by a liquid addition pump, extrusion was performed in the same manner as in Example 1 to obtain a film-like resin composition from the nozzle. It should be noted that the position of barrel C4 is 21 to 27% upstream relative to the effective length direction of the screw.

[0228] The moisture content of the resin composition extruded from the nozzle is 40% by mass. Afterwards, the film-like resin composition extruded from the nozzle is collected on a cooling roll to obtain a water-soluble film of thickness 100 μm. The appearance of the obtained water-soluble film is visually confirmed, and a white transparent film is obtained as a result, and no undissolved matter is confirmed. In addition, any part of the obtained water-soluble film is observed with a digital microscope (200 times), and the result confirms a filler with a size that can maintain anti-blocking properties.

[0229] <Example 3>

[0230] Except that a 24 mass % concentration of a plasticizer (b1) aqueous solution was added from the raw material supply port provided in barrel C6 instead of barrel C2 by a liquid addition pump, extrusion was performed in the same manner as in Example 1 to obtain a film-like resin composition from the nozzle. It should be noted that the position of barrel C6 is 34 to 41% upstream relative to the effective length direction of the screw.

[0231] The moisture content of the resin composition extruded from the nozzle is 40% by mass. Afterwards, the film-like object extruded from the nozzle is collected on a cooling roller to obtain a water-soluble film of thickness 100 μm. The appearance of the obtained water-soluble film is visually confirmed, and a white transparent film is obtained, and no undissolved matter is confirmed. In addition, any part of the obtained water-soluble film is observed with a digital microscope (200 times), and the filler having a size that can maintain anti-blocking property is confirmed.

[0232] <Example 4>

[0233] The barrel (C1, C2, C3, ..., C 15) is provided at the front end on the downstream side of the twin-screw extruder, with a head, a conduit and a T-die head.

[0234] At this time, the screw is configured as follows: the kneading disk area K1 is arranged at a position 45 to 51% of the upstream distance relative to the effective length direction of the screw, the kneading disk area K2 is arranged at a position 54 to 60% of the upstream distance, the kneading disk area K3 is arranged at a position 63 to 69% of the upstream distance, the kneading disk area K4 is arranged at a position 72 to 78% of the upstream distance, and the kneading disk area K5 is arranged at a position 90 to 93% of the upstream distance. The ratio (L / D) of the effective length (L) of the screw to the screw diameter (D) is 52.5, and the total length (L) of each kneading disk area is 52.5. KD ) ratio (L KD / L) is 0.27.

[0235] Further in barrels C1, C4 and C 13 It should be noted that the position of barrel C1 is 1 to 8% upstream of the effective length of the screw, the position of barrel C4 is 21 to 27% upstream of the effective length of the screw, and the position of barrel C 13 The position is 80-87% of the upstream distance relative to the effective length direction of the screw.

[0236] A raw material previously blended with 20 parts of a plasticizer (b2) and 1 part of a surfactant (d1) per 100 parts of a PVA-based resin (a1) was supplied to the twin-screw extruder from the raw material supply port of the barrel C1 using a feeder.

[0237] Separately, an aqueous solution of a plasticizer (b1) having a concentration of 19.8% by mass was prepared, and the aqueous solution was supplied to the twin-screw extruder from the raw material supply port of the barrel C4 using a liquid supply pump.

[0238] Furthermore, a filler (c1) aqueous solution with a concentration of 33% by mass was prepared and the mixture was added from the cylinder C. 13 The raw material supply port is used to supply the aqueous solution to the twin-screw extruder using a liquid addition pump.

[0239] At this time, the feed amount and the pumping amount were adjusted and supplied respectively so that PVA resin (a1) / plasticizer (b1) / plasticizer (b2) / filler (c1) / surfactant (d1) / water = 40.5 mass % / 8.1 mass % / 8.1 mass % / 3.3 mass % / 0.4 mass % / 39.6 mass %. It should be noted that the feeder part of the PVA resin (a1), the tank of the aqueous solution, and the pump part were set to room temperature.

[0240] C1~C 15 The set temperatures (T1 to T15) are set to T1 to T2 = 30°C, T3 to T 12 =90℃、T13 ~T 15 =70°C, the head, duct, and T-die were set to 70°C, and extrusion was performed to obtain a film-like resin composition from the nozzle.

[0241] The moisture content of the resin composition extruded from the nozzle is 40% by mass. Afterwards, the film-like resin composition extruded from the nozzle is collected on a cooling roll to obtain a water-soluble film of thickness 100 μm. The appearance of the obtained water-soluble film is visually confirmed, and a white transparent film is obtained as a result, and no undissolved matter is confirmed. In addition, any part of the obtained water-soluble film is observed with a digital microscope (200 times), and the result confirms a filler with a size that can maintain anti-blocking properties.

[0242] <Example 5>

[0243] In the effective length direction of the screw, there are 18 barrels (C1, C2, C3, ..., C 18 ) is provided at the front end on the downstream side of the twin-screw extruder, with a head, a conduit and a T-die head.

[0244] At this time, the screw is configured as follows: a kneading disk area K1 is arranged at a position 23 to 35% upstream relative to the effective length direction of the screw, a kneading disk area K2 is arranged at a position 36 to 48% upstream, a kneading disk area K3 is arranged at a position 49 to 60% upstream, a kneading disk area K4 is arranged at a position 62 to 70% upstream, a kneading disk area K5 is arranged at a position 71 to 79% upstream, and a kneading disk area K6 is arranged at a position 80 to 87% upstream, and in addition, a full-screw element is arranged. The ratio (L / D) of the effective length (L) of the screw to the screw diameter (D) is 63, and the total length (L) of each kneading disk area is 6. KD ) ratio (L KD / L) is 0.58.

[0245] The raw material supply ports are further provided in barrels C1, C3 and C4. It should be noted that the position of barrel C1 is 3-5% upstream relative to the effective length of the screw, the position of barrel C3 is 13-16%, and the position of barrel C4 is 19-22%.

[0246] A raw material composition containing 100 parts by mass of the PVA-based resin (a1), 8 parts by mass of the filler (C1-1), and 1 part by mass of the surfactant (d1) was supplied from the raw material supply port of the cylinder C1 using a feeder.

[0247] Furthermore, water was supplied from the raw material supply port of the barrel C3 by a liquid adding pump, and 41 mass % concentrations of plasticizer (b1) and 41 mass % concentrations of plasticizer (b2) were added from the raw material supply port of the barrel C4 by a liquid adding pump.

[0248] At this time, the feed amount and the pumping liquid amount are adjusted and supplied separately in such a manner that the PVA-based resin (a1) / plasticizer (b1) / plasticizer (b2) / filler (c1-1) / surfactant (d1) / water = 40.5 mass % / 8.1 mass % / 8.1 mass % / 3.3 mass % / 0.4 mass % / 39.6 mass %.

[0249] In addition, the feeder part of the PVA-based resin (a1), the tank of the aqueous solution, and the pump part were set to room temperature (23° C.).

[0250] Set the temperature of barrels C1 to C5 to 90°C and that of barrels C6 to C 16 The set temperature is set to 110℃ and the barrel C 17 ~C 18 The set temperature was set to 70° C., and the set temperatures of the head, the duct, and the T-die were set to 70° C. Extrusion was performed at a screw speed of 200 rpm to obtain a film-like resin composition from the nozzle.

[0251] The moisture content of the resin composition extruded from the nozzle is 40% by mass. Afterwards, the film-like resin composition extruded from the nozzle is collected on a cooling roll to obtain a water-soluble film of thickness 100 μm. The appearance of the obtained water-soluble film is visually confirmed, and a white transparent film is obtained as a result, and no undissolved matter is confirmed. In addition, any part of the obtained water-soluble film is observed with a digital microscope (200 times), and the result confirms a filler with a size that can maintain anti-blocking properties.

[0252] <Comparative Example 1>

[0253] Except that a 24 mass % concentration of a plasticizer (b1) aqueous solution was added from the raw material supply port provided in barrel C8 instead of barrel C2 by a liquid addition pump, extrusion was performed in the same manner as in Example 1 to obtain a film-like resin composition from the nozzle. It should be noted that the position of barrel C8 is 47 to 54% upstream relative to the effective length direction of the screw.

[0254] The moisture content of the resin composition extruded from the nozzle is 40% by mass. Afterwards, the film-like resin composition extruded from the nozzle is collected on a cooling roll to obtain a water-soluble film of 100 μm in thickness. The appearance of the obtained water-soluble film is visually confirmed, and the result is colored yellow, with many undissolved substances. In addition, any part of the obtained water-soluble film is observed with a digital microscope (200 times), and the result confirms a filler with a size that can maintain anti-blocking properties.

[0255] The conditions for producing the water-soluble films of Examples 1 to 5 and Comparative Example 1, and the results of the appearance evaluation of the obtained water-soluble films are shown in Table 1 below.

[0256] [Table 1]

[0257]

[0258] The water-soluble films produced in Examples 1 to 5 were found to have no coloring or undissolved matter of the PVA-based resin and were found to have excellent appearance. In addition, the inclusion of a filler also resulted in excellent anti-blocking properties.

[0259] On the other hand, the water-soluble film produced in Comparative Example 1 was colored yellow, contained a large amount of undissolved matter, and was a film with a significantly poor appearance. When the water-soluble film obtained in Comparative Example 1 was formed into a package, there was a concern that the film would break or pinholes would form, causing the contents to leak from the package, and it was found that it was not practical.

[0260] It should be noted that the above embodiments show specific aspects of the present invention, but the above embodiments are merely examples and are not to be construed as limiting. Various modifications obvious to those skilled in the art are intended to be within the scope of the present invention.

[0261] Industrial Applicability

[0262] The water-soluble film produced by the production method of the present invention can be used for various packaging applications, and is particularly useful for unit packaging of medicines and the like and for food packaging.

Claims

1. A method for producing a water-soluble film, characterized in that: in, The water-soluble polymer (A) and water are mixed and dissolved in a multi-screw extruder to obtain a resin composition (Z), and the obtained resin composition (Z) is extruded from a nozzle to form a water-soluble film. The multi-screw extruder comprises: a plurality of temperature-adjustable barrels and a plurality of screws formed by combining a plurality of screw elements. When the temperature-adjustable barrels are respectively designated as C1, C2, C3, etc. from the upstream, the barrel provided with a raw material supply port for supplying a raw material containing the water-soluble polymer (A) as a main component is designated as C S , the barrel provided with the raw material supply port most upstream of the raw material supply ports for supplying the raw material containing water is set as C T , 0≤TS≤6, where S and T are integers greater than 1, The ratio (L / D) of the effective length (L) of the screw to the diameter (D) of the screw exceeds 50 and is 100 or less.

2. The method for producing a water-soluble film according to claim 1, characterized in that: The screw has a kneading disk area, and the kneading disk area is set to K1, K2, K3, ..., K m When K m The kneading area is located at the most downstream side, and the upstream end of the kneading disc area K1 is located at a position lower than the barrel C T Also close to downstream.

3. The method for producing a water-soluble film according to claim 2, characterized in that: The barrel having a plurality of raw material supply ports for supplying the raw material containing water is set as C u When the kneading disk area K m The upstream end is located at a position lower than the barrel portion C u Also close to downstream.

4. The method for producing a water-soluble film according to claim 2 or 3, characterized in that: The barrel having a plurality of raw material supply ports for supplying the raw material containing water is set as C u When the kneading disk area K m-1 The downstream end is located at a position lower than the barrel portion C u Also close to the upstream, where m is set to an integer greater than 2.

5. The method for producing a water-soluble film according to claim 1 or 2, characterized in that: The water-soluble polymer (A) includes a polyvinyl alcohol-based resin.

6. The method for producing a water-soluble film according to claim 1 or 2, characterized in that: The resin composition (Z) extruded from the nozzle has a water content of 20 to 60% by mass.

7. The method for producing a water-soluble film according to claim 1 or 2, characterized in that: The plasticizer (B) is contained in an amount of 10 to 60 parts by mass based on 100 parts by mass of the water-soluble polymer (A).

8. A water-soluble film, characterized in that: The water-soluble film is produced by the method for producing a water-soluble film according to claim 1 or 2.

9. A packaging body formed of the water-soluble film according to claim 8. 10 . A medicine package, comprising: a package formed of the water-soluble film according to claim 8 and a medicine packaged by the package.

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