JP4570742B2 - Water-soluble film - Google Patents

Description

【００４５】
【表２】

【００４６】
【表３】

【００４７】
【表４】

【００４８】
【発明の効果】
上記の実施例により明らかなように、本発明のＰＶＡ系樹脂、可塑剤及び無機フィラーから得られたフィルムは水溶性が良好であり、高湿下でのフィルムの腰の強さなどの取り扱い性が向上し工程通過性が改善されている。これは、ＰＶＡ系樹脂として１，２−グリコール結合量が１．８モル％以上、けん化度が９２〜９６モル％のＰＶＡ系樹脂と、特定量の可塑剤および特定量の無機フィラーを用いることによって達成されたものである。
本発明の水溶性フィルムは上記の特徴を生かして、染料、洗剤、農薬、トイレ洗浄剤、入浴剤、消毒剤、弱酸性物質、弱アルカリ性物質、塩素系物質などの各種薬剤の包装用途や、曲面印刷用途など従来公知の水溶性フィルムの用途に用いることができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a water-soluble film comprising a polyvinyl alcohol (hereinafter abbreviated as PVA) resin having excellent water solubility and moisture resistance.
[0002]
[Prior art]
In recent years, various chemicals such as agricultural chemicals are sealed and packaged in water-soluble films in unit quantities, put into water in their packaging form at the time of use, and the contents are dissolved or dispersed in water together with the packaging film. Many methods have been used. The advantage of this unit packaging is that it can be used without direct contact with hazardous chemicals during use, that it does not require weighing during use because a certain amount is packaged, and after use of containers or bags that have been packed, transported, etc. This processing is unnecessary or simple.
Conventionally, an unmodified partially saponified PVA film having a saponification degree of about 88 mol% has been used as such a water-soluble film for unit packaging. These water-soluble films are easily soluble in cold water and hot water, and have performances such as excellent mechanical strength. However, the partially saponified PVA film absorbs moisture in the air under high humidity and loses its waist, adheres to the roll, deteriorates processability, or breaks when the packaging bags peel off due to blocking. There is a demand for a water-soluble film that has a drawback such as rustling and has a waist even under high humidity.
[0003]
[Problems to be solved by the invention]
Under such circumstances, the present invention has improved water-soluble solubility such as waist strength of the film under high humidity while maintaining the water-solubility of the water-soluble film made of the conventional PVA resin. A film is provided.
[0004]
[Means for Solving the Problems]
The present inventors have made intensive studies toward the solving the problems, 1,2-glycol bond content of 1.8 mol% or more and a saponification degree ninety-two to nine PVA-based resin 100 parts by weight of 6 mol%, A water-soluble film comprising 20 to 50 parts by weight of a plasticizer and 1 to 20 parts by weight of an inorganic filler, and having a dissolution time in water of 20 ° C. of 50 seconds or less and a Young's modulus of 1.5 kg / mm ² or more. The present invention has been completed by finding that the water-soluble film having the characteristics achieves the above object.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
[0006]
In the present invention, the PVA resin is a saponified product of a polyvinyl ester resin.
Examples of the vinyl ester include vinyl esters such as vinyl formate, vinyl acetate, vinyl propionate, vinyl valerate, vinyl laurate, vinyl benzoate, vinyl stearate, vinyl pivalate and vinyl versatate. Vinyl acetate is preferred from the standpoint of productivity and ease of formation of 1,2-glycol bonds.
[0007]
The vinyl ester is preferably copolymerized with a small amount of an α-olefin having 4 or less carbon atoms in order to improve biodegradability. Examples of the α-olefin having 4 or less carbon atoms include ethylene, propylene, n-butene, and isobutylene, and ethylene is particularly preferable from the viewpoint of improving the biodegradability of the polymer film to be obtained. Propylene is particularly preferred from the viewpoint of improving water solubility. The α-olefin content in the copolymerized PVA-based resin is 0.1 to 10 mol%, preferably 0.5 to 5 mol%. When the content of α-olefin is less than 0.1 mol%, the effect of improving biodegradability is not observed. Conversely, when the content exceeds 10 mol%, the film strength decreases due to a decrease in the degree of polymerization. It is not preferable. In particular, when ethylene is copolymerized, the water solubility is lowered, so 5 mol% or less is preferable.
[0008]
In the present invention, the PVA-based resin may contain other monomer units as long as the gist of the present invention is not impaired. Examples of such comonomers include acrylic acid and salts thereof and methyl acrylate, ethyl acrylate, n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, i-butyl acrylate, and t-butyl acrylate. Acrylates such as 2-ethylhexyl acrylate, dodecyl acrylate, octadecyl acrylate, methacrylic acid and salts thereof, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, i-propyl methacrylate, n methacrylate -Methacrylic acid esters such as butyl, i-butyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, dodecyl methacrylate, octadecyl methacrylate, acrylamide, N-methylacrylamide, N-ethylacrylamide N, N-dimethylacrylamide, diacetoneacrylamide, acrylamidepropanesulfonic acid and its salt, acrylamidepropyldimethylamine and its salt or quaternary salt thereof, acrylamide derivatives such as N-methylolacrylamide and its derivatives, methacrylamide, N-methyl Methacrylamide derivatives such as methacrylamide, N-ethyl methacrylamide, methacrylamide propane sulfonic acid and salts thereof, methacrylamide propyldimethylamine and salts thereof or quaternary salts thereof, N-methylol methacrylamide and derivatives thereof, and N-vinylpyrrolidone N-vinylamides such as N-vinylformamide and N-vinylacetamide, allyl ethers having a polyalkylene oxide in the side chain, methyl vinyl ether Ter, ethyl vinyl ether, n-propyl vinyl ether, i-propyl vinyl ether, n-butyl vinyl ether, i-butyl vinyl ether, t-butyl vinyl ether, dodecyl vinyl ether, vinyl ethers such as stearyl vinyl ether, nitriles such as acrylonitrile, methacrylonitrile, Vinyl halides such as vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride, allyl compounds such as allyl acetate and allyl chloride, maleic acid and its salts or esters, vinylsilyl compounds such as vinyltrimethoxysilane, isopropenyl acetate Etc. The amount of modification is usually 5 mol% or less.
[0009]
As the polymerization method of the polyvinyl ester resin, conventionally known methods such as solution polymerization method, bulk polymerization method, suspension polymerization method and emulsion polymerization method can be applied. As the polymerization catalyst, an azo catalyst, a peroxide catalyst, a redox catalyst or the like is appropriately selected according to the polymerization method.
[0010]
For the saponification reaction of the polyvinyl ester resin, alcoholysis or hydrolysis with a conventionally known alkali catalyst or acid catalyst can be applied. Of these, a saponification reaction with a NaOH catalyst using methanol as a solvent is simple and most preferred.
[0011]
Saponification degree of the PVA-based resin in the present invention is required to be 92 mole% to 9 6 mol%, preferably 94 mol% to 96 mol%. When the saponification degree of the PVA resin is less than 92 mol%, the alkali resistance is lowered or the hygroscopicity is large, which is not preferable. On the other hand, if it exceeds 99 mol%, it is not preferable because water solubility is lowered.
[0012]
The amount of 1,2-glycol bonds in the PVA-based resin is essential to be 1.8 mol% or more, more preferably 2.2 mol% or more, and further preferably 2.5 mol% or more. The amount of 1,2-glycol bond can be controlled by various methods such as vinyl ester type, solvent, polymerization temperature, and copolymerization of vinylene carbonate. As a simple control method, in the present invention, control with polymerization temperature or vinylene carbonate is preferred. There is no upper limit on the amount of 1,2-glycol bonds, but if the polymerization temperature is increased or vinylene carbonate or the like is copolymerized to increase the amount of 1,2-glycol bonds, the degree of polymerization will occur. Is preferably 5 mol% or less, more preferably 4 mol% or less, and even more preferably 3.5 mol% or less.
When the polymerization temperature is controlled, the polymerization temperature is 80 ° C or higher, preferably 100 ° C or higher, more preferably 120 ° C or higher, further preferably 150 ° C or higher, and particularly preferably 180 ° C or higher.
[0013]
The degree of polymerization of the PVA resin also affects the performance of the water-soluble film of the present invention. The degree of polymerization is appropriately selected depending on the use of the film, but the degree of polymerization is preferably 500 or more from the viewpoint of film strength, more preferably 700 or more, still more preferably 900 or more, and 3000 or less from the viewpoint of industrial productivity. It is. Further, from the viewpoint of impact resistance required when a water-soluble film is used as a bag, a polymerization degree of 1000 or more is particularly preferable.
[0014]
The short chain branching amount of the PVA resin is preferably 0.03 mol% or more, more preferably 0.05 mol% or more. Short chain branching can be controlled by various methods such as the type of vinyl ester, solvent, and polymerization temperature. As a simple control method, control at the polymerization temperature is preferred in the present invention. Since the crystallinity of the PVA resin is expected to decrease as the amount of short chain branching increases, the water solubility is improved and a preferable water soluble film is obtained. The polymerization temperature is 80 ° C. or higher, preferably 100 ° C. or higher, more preferably 120 ° C. or higher, further preferably 150 ° C. or higher, and particularly preferably 180 ° C. or higher.
[0015]
In general, a water-soluble film is transported, stored, and used even in a hot and humid region or a cold region, so that the strength and toughness of the film are required. In particular, impact resistance at low temperatures is required. Therefore, various plasticizers are used to lower the glass transition point of the obtained film. Furthermore, in the present invention, in addition to the above-described purpose, a plasticizer is used for the purpose of improving the solubility in water.
[0016]
The plasticizer used in the present invention is not particularly limited as long as it is generally used as a plasticizer for a PVA resin. For example, glycerin, diglycerin, trimethylolpropane, diethylene glycol, triethylene glycol, dipropylene glycol, Polyhydric alcohols such as propylene glycol, polyethers such as polyethylene glycol and polypropylene glycol, phenol derivatives such as bisphenol A and bisphenol S, amide compounds such as N-methylpyrrolidone, polyhydric alcohols such as glycerin, pentaerythritol and sorbitol Examples thereof include compounds obtained by adding ethylene oxide to one of these, and one or more of these can be used. Among these, glycerin, trimethylolpropane, diethylene glycol, triethylene glycol, dipropylene glycol, and propylene glycol are preferable for the purpose of improving water solubility, and trimethylolpropane is particularly effective for improving water solubility. Particularly preferred.
[0017]
It is essential that the blending ratio of the plasticizer is 20 to 50 parts by weight with respect to 100 parts by weight of the PVA resin. When the blending ratio of the plasticizer is less than 1 part by weight, the blending effect of the plasticizer is not recognized. On the other hand, when the blending ratio of the plasticizer exceeds 50 parts by weight, the bleed-out of the plasticizer becomes large, and the anti-blocking property of the resulting film tends to deteriorate. Point or these dissolution rate in water of the resulting film, you in a proportion of more than 20 parts by weight. Moreover, it is preferable to mix | blend in the ratio of 40 weight part or less from the point of the waist of a film obtained (it is important at the point of process passability, such as a bag making machine). From the viewpoint of improving the water solubility of the resulting film, the greater the amount of plasticizer, the better. Further, the heat seal temperature varies depending on various factors, but in particular, the greater the amount of the plasticizer, the lower the heat seal temperature, which is preferable because the productivity at the time of making a film is improved. In particular, the plasticizer is preferably blended at a rate such that the heat seal temperature of the resulting film is 170 ° C. or less, and more preferably blended at a rate such that the heat seal temperature is 160 ° C. or less. Furthermore, the compounding amount of the plasticizer tends to affect the magnitude of Young's modulus of the obtained film. From the point of process passability of the obtained film bag making machine or the like, it is essential that the Young's modulus is 1.5 kg / mm ² or more, more preferably ² kg / mm ² or more. It is preferable to add a plasticizer so as to obtain a film having a Young's modulus in a range.
[0018]
In the present invention, it is essential to add an inorganic filler to the PVA resin. Examples of the inorganic filler used in the present invention include silica, heavy, light or surface-treated calcium carbonate, aluminum hydroxide, aluminum oxide, titanium oxide, diatomaceous earth, barium sulfate, calcium sulfate, zeolite, zinc oxide, and silicic acid. , Silicate, mica, magnesium carbonate, and clays such as kaolin, halosite, pyroferrite, and sericite, talc, and the like, and one or more of these can be used. Among these, it is particularly preferable to use silica from the viewpoint of dispersibility in PVA. The particle diameter of the inorganic filler is preferably 1 μm or more from the viewpoint of blocking prevention, and is preferably 10 μm or less from the viewpoint of dispersibility in PVA. In order to achieve both performances, a particle size of about 1 to 7 μm is more preferable.
[0019]
The blending amount of the inorganic filler is essential to be 1 to 20 parts by weight, more preferably 3 to 20 parts by weight, more preferably 5 to 5 parts by weight with respect to 100 parts by weight of the PVA resin from the viewpoint of improving water solubility. The amount is more preferably 20 parts by weight, particularly preferably 10 to 20 parts by weight. It is preferable to add an inorganic filler within these ranges because a water-soluble film having better antiblocking properties can be obtained. In addition, when it mixes exceeding 20 weight part of inorganic fillers, the dispersibility to PVA will fall, an inorganic filler will aggregate, and there exists a tendency for the water solubility of the film obtained to fall.
[0020]
In the present invention, 1,2-glycol bond content of 1.8 mol% or more and a saponification degree of 92-9 6 mole% of the PVA-based resin, in addition to the plasticizer and the inorganic filler, further monosaccharides and / or multi It is even more preferable to add a saccharide (preferably starch) in terms of improving the water solubility of the resulting film.
The monosaccharide and / or polysaccharide used in the present invention is not particularly limited, and examples of the monosaccharide include glucose, fructose, isomerized sugar, xylose, and the like, including polysaccharides (disaccharides and oligosaccharides). ) As maltose, lactose, sucrose, trehalose, palatinose, reduced maltose, reduced palatinose, reduced lactose, starch syrup, isomaltoligosaccharide, fructooligosaccharide, lactose oligosaccharide, soybean oligosaccharide, xylooligosaccharide, coupling sugar, cyclodextrin compound , Pullulan, pectin, agar, konjac mannan, polydextrose, xanthan gum, starch and the like.
Of these, starch is most preferred.
There is no particular limitation on the type of the starch, for example, raw starch such as corn, wheat, potato, tapioca, taro, sweet potato, rice, etc., and pregelatinized starch, dextrin, oxidized starch, aldehyde starch, and esterified starch. And modified starches such as etherified starch, cationized starch, and crosslinked starch, and one or more of these can be used. From the viewpoint of process passability of the resulting film bag making machine, etc., the compatibility between PVA and starch is somewhat low, and the film surface is preferably matte. Raw corn starch, oxidized corn starch, etherified corn starch, phosphorus Acid esterified potato starch and acetylated wheat starch are preferred. Furthermore, oxidized corn starch is particularly preferable from the viewpoint that fine irregularities are favorably formed on the film surface.
[0021]
The blending ratio of the monosaccharide and / or polysaccharide (preferably starch) is 5 to 50 parts by weight, preferably 10 to 35 parts by weight, based on 100 parts by weight of the PVA resin.
When the blending ratio is less than 5 parts by weight, the effect of improving the dissolution rate of the obtained film in water is not observed. On the other hand, when the blending ratio exceeds 50 parts by weight, the strength of the obtained film is lowered. From the viewpoint of antiblocking properties of the resulting film, it is preferable to blend 10 parts by weight or more.
[0022]
In the present invention, the PVA-based resin may further contain, as necessary, usual additives such as a colorant, a fragrance, an extender, an antifoaming agent, a release agent, an ultraviolet absorber, and a surfactant. Absent. In particular, in order to improve the releasability between the metal surface such as a die or drum of the film forming apparatus and the formed film or film stock solution, the ratio of 0.01 to 5 parts by weight of the surfactant with respect to 100 parts by weight of PVA It is preferable to mix with. If necessary, water-soluble polymers such as PVA resin, carboxymethylcellulose, methylcellulose, and hydroxymethylcellulose having a 1,2-glycol bond content of less than 1.8 mol% may be added within a range not losing the effects of the present invention. You may mix. In particular, from the viewpoint of improving water solubility, it is preferable to add a low viscosity type carboxymethylcellulose.
[0023]
In the present invention, the PVA-based resin contains a plasticizer, an inorganic filler, more preferably a monosaccharide and / or polysaccharide (preferably starch), or, if necessary, other ingredients described above. It can be used for production of a film by mixing in a desired method.
[0024]
The method for producing the water-soluble film of the present invention using the PVA-based resin as described above is not particularly limited, and is appropriately selected depending on the required film thickness, film application, and purpose, but is usually cast from a solution. Film forming method, inflation film forming method, coating method, dry film forming method (extrusion into an inert gas such as air or nitrogen), wet film forming method (extrusion into the poor solvent of the PVA resin), dry and wet It is performed by a formula film forming method, a gel film forming method, or the like. As the solvent used at this time, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, ethylene glycol, glycerin, water, hexafluoroisopropanol or the like is used alone or in combination. Also, an aqueous solution of an inorganic salt such as lithium chloride or calcium chloride can be used alone or mixed with the organic solvent. Of these, water, dimethyl sulfoxide, a mixed solution of dimethyl sulfoxide and water, glycerin, ethylene glycol and the like are preferably used. The concentration of the film forming stock solution is preferably 50% by weight or less (the solvent content is more than 50% by weight) from the viewpoint of viscosity, and 30% by weight or less (solvent from the point that a mat state is easily formed on the surface of the film formed. Is more preferable than 70% by weight). The film forming temperature is usually in the range of room temperature to 250 ° C. The stretching or rolling operation can be performed with dry heat or wet heat, and the temperature is usually in the range of room temperature to 270 ° C. Moreover, the dissolution rate can be controlled by applying a heat treatment of about 100 to 150 ° C. after the film formation. Moreover, in order to improve blocking prevention property and water solubility, it is preferable to perform mat processing of the film surface, spraying of an antiblocking agent, and embossing.
[0025]
The water-soluble film of the present invention has an excellent dissolution rate in water, and it is essential that the complete dissolution time in 20 ° C. water (film thickness 40 μm) is 50 seconds or less, and 40 seconds or less. It is more preferable that The complete dissolution time in 20 ° C. water referred to in the present invention is a value obtained by measuring the time (DT) until the film is completely dissolved according to the method described as the method for measuring the water solubility of the water-soluble film in the examples described later. When a film having a thickness different from 40 μm is used, the value is converted to a film thickness of 40 μm according to the formula (1) described later.
[0026]
The water-soluble film of the present invention has an excellent bag breaking rate into water, and the bag breaking time in 20 ° C. water (film thickness 40 μm) is preferably 30 seconds or less, and 20 seconds or less. More preferably it is. The bag breaking time in 20 ° C. water referred to in the present invention is a value obtained by measuring the time (BT) until the film breaks according to the method described as the method for measuring the water solubility of the water-soluble film in the examples described later. When a film having a thickness different from 40 μm is used, the film thickness is a value converted to a film thickness of 40 μm by the following formula (2).
[0027]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples. In the examples, “parts” and “%” mean “parts by weight” and “% by weight” unless otherwise specified.
[0028]
[Analysis method of PVA]
The analysis method of PVA followed JIS-K6726 unless otherwise specified.
The content of 1,2-glycol bond and short chain branching of the PVA of the present invention was determined from the measurement with a 500 MHz ¹ H NMR (JEOL GX-500) apparatus as follows.
(1) The amount of 1,2-glycol bonds in PVA can be determined from the NMR peak. After saponification to a saponification degree of 99.9 mol% or more, the sample was thoroughly washed with methanol, then dried at 90 ° C. under reduced pressure for 2 days, dissolved in DMSO-d6, and a sample added with a few drops of trifluoroacetic acid was added at 500 MHz. It measured at 80 degreeC using < ¹ > H NMR (JEOL GX-500).
The peak derived from methine of the vinyl alcohol unit is attributed to 3.2 to 4.0 ppm (integrated value A), and the peak derived from one methine of the 1,2-glycol bond is attributed to 3.25 ppm (integrated value B). The 1,2-glycol bond content can be calculated.
1,2-glycol bond amount (mol%) = (B / A) × 100
(2) The amount of short chain branching of PVA (consisting of 2 monomer units) can be determined from the NMR peak. After saponification to a degree of saponification of 99.9 mol% or more, the sample was thoroughly washed with methanol, and then dried at 90 ° C. under reduced pressure for 2 days. A sample (1) in which DMVA-d6 was dissolved was analyzed by 500 MHz ¹ H NMR. Sample (2) dissolved in D ₂ O is measured at 80 ° C. using ¹³ C NMR (JEOL GX-500) of 125.65 MHz.
From sample (1), the methine-derived peak of the vinyl alcohol unit is attributed to 3.2 to 4.0 ppm (integrated value C), and the peak derived from the methylene of the terminal alcohol is attributed to 3.52 ppm (integrated value D). From ▼, the methylene-derived peak of all terminal alcohols is attributed to 60.95 to 61.65 ppm (integral value E), and the methylene-derived peak of short-chain branched terminal alcohols is attributed to 60.95 to 61.18 ppm (integrated value F). The short chain branching content can be calculated by the following formula.
Short chain branching content (mol%) = [(D / 2) / C] × (F / E) × 100
[0029]
[Method for measuring water solubility of water-soluble film]
Install a magnetic stirrer in a constant temperature bath at 20 ° C. A 1 L glass beaker containing 1 L of distilled water is placed in a bath and agitated at 250 rpm using a 5 cm rotor. After the distilled water in the beaker reaches 20 ° C., the water solubility measurement is started. (When measuring at 10 ° C. and 15 ° C., the same operation is performed with the temperature condition set to a predetermined temperature.)
A 40 μm thick film was cut into a 40 × 40 mm square, sandwiched between slide mounts, immersed in 20 ° C. stirring water, and the dissolved state of the film was observed. The time until the film was broken was measured as BT, and the time until the film was completely dissolved as DT. When a film having a film thickness different from 40 μm is used, the film thickness is converted into a value of 40 μm according to the following formulas (1) and (2).
[0030]
Conversion dissolution time (seconds) = [40 / film thickness (μm)] ² × sample dissolution time (seconds) (1)
Conversion bag breaking time (seconds) = [40 / film thickness (μm)] ² × sample bag breaking time (seconds) (2)
[0031]
[Measurement method of Young's modulus]
A film having a thickness of 40 μm and a width of 10 mm was conditioned at 20 ° C. and 65% RH for 1 week, and then subjected to a tensile test by an autograph. The chuck interval was 50 mm, and the pulling speed was 500 mm / min. The Young's modulus was obtained from the initial value of tension. It shows that it is excellent in process-passability, so that this value is large.
[0032]
Example 1
A 5 L pressure reactor equipped with a stirrer, nitrogen inlet, and initiator inlet was charged with 3000 g vinyl acetate and 0.090 g tartaric acid, and the reactor pressure was increased to 2.0 MPa while bubbling with nitrogen gas at room temperature. The system was allowed to stand for 10 minutes, and then the operation of releasing the pressure was repeated three times to purge the system with nitrogen. A 0.1 g / L solution having a concentration of 2,2′-azobis (N-butyl-2-methylpropionamide) dissolved in methanol as an initiator was prepared, and nitrogen substitution was performed to perform bubbling with nitrogen gas. Next, the temperature inside the polymerization tank was raised to 150 ° C. The reaction vessel pressure at this time was 0.8 MPa. Next, 8.0 ml of the above initiator solution was injected to initiate polymerization. During the polymerization, the polymerization temperature was maintained at 150 ° C., and 2,2′-azobis (N-butyl-2-methylpropionamide) was continuously added at 13.6 ml / hr using the above initiator solution. Carried out. The reactor pressure during the polymerization was 0.8 MPa. After 3 hours, the polymerization was stopped by cooling. The solid concentration at this time was 25%. Subsequently, unreacted vinyl acetate monomer was removed while adding methanol occasionally under reduced pressure at 30 ° C. to obtain a methanol solution of polyvinyl acetate (concentration: 33%). To 400 g of a polyvinyl acetate methanol solution (100 g of polyvinyl acetate in the solution) adjusted to a concentration of 25% by adding methanol to the obtained polyvinyl acetate solution, 2.3 g (polyacetic acid at 40 ° C.). Saponification was carried out by adding an alkaline solution (NaOH in 10% methanol) having a molar ratio (MR) of 0.010) to vinyl acetate units in vinyl. After about 20 minutes after the addition of alkali, the gelled material was pulverized by a pulverizer and allowed to stand for 1 hour to allow saponification to proceed, and then 1000 g of methyl acetate was added to neutralize the remaining alkali. After confirming the end of neutralization using a phenolphthalein indicator, 1000 g of methanol was added to white solid polyvinyl alcohol (hereinafter abbreviated as PVA) obtained by filtration, and the mixture was left to wash at room temperature for 3 hours. After the above washing operation was repeated three times, the PVA obtained by centrifugal drainage was left in a dryer at 70 ° C. for 2 days to obtain dry PVA (PVA-1).
[0033]
The degree of saponification of the obtained PVA (PVA-1) was 95 mol%.
In addition, a methanol solution of polyvinyl acetate obtained by removing unreacted vinyl acetate monomer after polymerization was saponified at an alkali molar ratio of 0.5, and the pulverized product was allowed to stand at 60 ° C. for 5 hours to promote saponification. After that, Soxhlet washing with methanol was carried out for 3 days, followed by drying under reduced pressure at 80 ° C. for 3 days to obtain purified PVA. It was 1200 when the polymerization degree of this PVA was measured according to JIS-K6726 of the conventional method. The amount of 1,2-glycol bonds in the purified PVA was determined by measurement with a 500 MHz ¹ H NMR (JEOL GX-500) apparatus as described above, and it was 2.5 mol%.
[0034]
To 100 parts by weight of the obtained polyvinyl alcohol resin, 40 parts by weight of trimethylolpropane, 20 parts by weight of oxidized corn starch, 10 parts by weight of silica having an average particle size of 3 μm, and 900 parts by weight of water are added and stirred at 90 ° C. Then, a PVA concentration 10% aqueous solution was prepared. The aqueous solution was sufficiently degassed at 80 ° C., then cast on a polyester film whose surface was matted, and dried at 90 ° C. Thereafter, heat treatment was performed at 100 ° C. for 10 minutes. The thickness of the obtained film was 40 μm, and it was a matte film with 1 μm irregularities formed on one side.
Using the obtained film, water solubility at 20 ° C. and Young's modulus were measured. The results obtained are shown in Table 4.
[0035]
Example 2
Polymerization and saponification were carried out in the same manner as in Example 1 except that the polymerization temperature was changed to 120 ° C. The conditions for PVA synthesis are shown in Table 1, and the analytical value of the obtained resin (PVA-2) is shown in Table 2.
And operation similar to Example 1 was performed, the film of the composition shown in Table 3 was created, water solubility and Young's modulus were evaluated, and the result was shown in Table 4.
[0036]
Example 3
Polymerization and saponification were carried out in the same manner as in Example 1 except that the polymerization temperature was changed to 180 ° C. The conditions for PVA synthesis are shown in Table 1, and the analytical value of the obtained resin (PVA-3) is shown in Table 2.
And operation similar to Example 1 was performed, the film of the composition shown in Table 3 was created, water solubility and Young's modulus were evaluated, and the result was shown in Table 4.
[0037]
Examples 4 and 6
Using the resin (PVA-1) obtained in Example 1, a film having the composition shown in Table 3 was prepared in the same manner as in Example 1, and water solubility and Young's modulus were evaluated. This is shown in FIG.
[0038]
Example 5
Polymerization and saponification were carried out in the same manner as in Example 1 except that the PVA synthesis conditions were changed as shown in Table 1. The analytical values of the obtained resin (PVA-10) are shown in Table 2.
And operation similar to Example 1 was performed, the film of the composition shown in Table 3 was created, water solubility and Young's modulus were evaluated, and the result was shown in Table 4.
[0039]
Example 7
A 50 L pressure reactor equipped with a stirrer, nitrogen inlet, ethylene inlet, initiator addition port and delay solution addition port was charged with 29.4 kg of vinyl acetate and 0.6 kg of methanol. The system was purged with nitrogen by nitrogen bubbling for 1 minute. Next, ethylene was introduced and charged so that the reactor pressure was 1.8 MPa.
A solution having a concentration of 0.1 g / L in which 2,2′-azobis (N-butyl-2-methylpropionamide) was dissolved in methanol as an initiator was prepared, and nitrogen substitution was performed to perform bubbling with nitrogen gas. After adjusting the polymerization tank internal temperature to 150 ° C., 45 ml of the initiator solution was injected to initiate polymerization. During the polymerization, ethylene was introduced to maintain the reactor pressure at 1.8 MPa and the polymerization temperature at 150 ° C., and using the above initiator solution, 2,2′-azobis (N-butyl-2) at 185 ml / hr. -Methylpropionamide) was added continuously to carry out the polymerization. After 3 hours, when the polymerization rate reached 25%, the polymerization was stopped by cooling. After the reaction vessel was opened to remove ethylene, nitrogen gas was bubbled to completely remove ethylene. Next, unreacted vinyl acetate monomer was removed under reduced pressure to obtain a methanol solution of polyvinyl acetate. To 333 g of a polyvinyl acetate methanol solution (100 g of polyvinyl acetate in the solution) adjusted to have a concentration of 30% by adding methanol to the obtained polyvinyl acetate solution, 9.3 g (in polyvinyl acetate) Saponification was performed by adding an alkaline solution (NaOH in 10% methanol) having a molar ratio (MR) of 0.011) to the vinyl acetate unit. About 5 minutes after the addition of the alkali, the gelled system was pulverized with a pulverizer and allowed to stand at 40 ° C. for 1 hour to allow saponification to proceed, and then 1000 g of methyl acetate was added to neutralize the remaining alkali. After confirming the end of neutralization using a phenolphthalein indicator, 1000 g of methanol was added to the white solid PVA obtained by filtration, and the mixture was left to wash at room temperature for 3 hours. After the above washing operation was repeated three times, the PVA obtained by centrifugal drainage was left in a dryer at 70 ° C. for 2 days to obtain dry PVA (PVA-4). When the above-described analysis was performed on the obtained ethylene-modified PVA, the polymerization degree of PVA-4 was 1150, the saponification degree was 95 mol%, and the ethylene modification amount was 3 mol%.
The analytical value of the obtained resin (PVA-4) is shown in Table 2.
And operation similar to Example 1 was performed, the film of the composition shown in Table 3 was created, water solubility and Young's modulus were evaluated, and the result was shown in Table 4.
[0040]
Reference example 1
Polymerization and saponification were carried out in the same manner as in Example 1 except that propylene was used instead of nitrogen as a replacement gas in the reaction vessel, and the conditions during the polymerization were changed as shown in Table 1. The analytical values of the obtained resin (PVA-5) are shown in Table 2. However, as for the amount of propylene modification, the DSC of the polymer saponified to a saponification degree of 99.9 mol% was measured to obtain the melting point, and the modification amount [Δ ( Mol%)].
Δ = (234.1-Tm) /7.55
And operation similar to Example 1 was performed, the film of the composition shown in Table 3 was created, water solubility and Young's modulus were evaluated, and the result was shown in Table 4.
[0041]
Example 8
A 5 L four-necked separable flask equipped with a stirrer, nitrogen inlet, initiator inlet, and reflux condenser was charged with 2000 g of vinyl acetate, 400 g of methanol, and 78.8 g of vinylene carbonate, and the system was bubbled with nitrogen for 30 minutes at room temperature. The inside was replaced with nitrogen. After adjusting the polymerization tank internal temperature to 60 ° C., 0.9 g of α, α′-azobisisobutyronitrile was added as an initiator to initiate polymerization. During the polymerization, the polymerization temperature was maintained at 60 ° C., and after 4 hours, the polymerization was stopped by cooling. The solid concentration at this time was 55%. Subsequently, unreacted vinyl acetate monomer was removed while adding methanol occasionally under reduced pressure at 30 ° C. to obtain a methanol solution of polyvinyl acetate (concentration: 33%). 46.4 g (polyacetic acid) at 40 ° C. was added to 400 g of a polyvinyl acetate methanol solution adjusted to a concentration of 25% by adding methanol to the obtained polyvinyl acetate solution (100 g of polyvinyl acetate in the solution). Saponification was carried out by adding an alkaline solution (NaOH in 10% methanol) having a molar ratio (MR) of 0.010) to vinyl acetate units in vinyl. After about 1 minute after addition of the alkali, the gelled product was pulverized with a pulverizer and allowed to stand for 1 hour to allow saponification to proceed, and then 1000 g of methyl acetate was added to neutralize the remaining alkali. After confirming the end of neutralization using a phenolphthalein indicator, 1000 g of methanol was added to the white solid PVA obtained by filtration, and the mixture was left to wash at room temperature for 3 hours. After the washing operation was repeated three times, the PVA obtained by centrifugal drainage was left in a dryer at 70 ° C. for 2 days to obtain dry PVA (PVA-9).
The degree of saponification of the obtained PVA (PVA-9) was 95 mol%.
Further, after saponification of a methanol solution of polyvinyl acetate obtained by removing unreacted vinyl acetate monomer after polymerization at an alkali molar ratio of 0.5, the pulverized product was allowed to stand at 60 ° C. for 5 hours to promote saponification. After that, Soxhlet washing with methanol was carried out for 3 days, followed by drying under reduced pressure at 80 ° C. for 3 days to obtain purified PVA. When the degree of polymerization of the PVA was measured according to a conventional method JIS K6726, it was 1700. The amount of 1,2-glycol bonds in the purified PVA was determined as described above from measurement with a 500 MHz ¹ H NMR (JEOL GX-500) apparatus and found to be 3.0 mol%.
And operation similar to Example 1 was performed, the film of the composition shown in Table 3 was created, water solubility and Young's modulus were evaluated, and the result was shown in Table 4.
[0042]
Comparative Examples 1 to 4
Polymerization and saponification were carried out in the same manner as in Example 1 except that the PVA synthesis conditions were changed as shown in Table 1. The analytical values of the obtained resin are shown in Table 2.
And operation similar to Example 1 was performed, the film of the composition shown in Table 3 was created, water solubility and Young's modulus were evaluated, and the result was shown in Table 4.
[0043]
Comparative Example 5
900 parts by weight of water was added to 100 parts by weight of polyvinyl alcohol (PVA-8) having a 1,2-glycol bond amount of 1.6 mol%, a polymerization degree of 1400 and a saponification degree of 95 mol%, polymerized at a polymerization temperature of 60 ° C. And stirred at 90 ° C. to prepare a 10% aqueous solution. The aqueous solution was sufficiently degassed at 60 ° C., then cast on a polyester film, and dried at 90 ° C. Thereafter, heat treatment was performed at 100 ° C. for 10 minutes. Table 4 shows the water solubility and Young's modulus of the film obtained.
[0044]
[Table 1]

[0045]
[Table 2]

[0046]
[Table 3]

[0047]
[Table 4]

[0048]
【The invention's effect】
As is clear from the above examples, the film obtained from the PVA resin of the present invention, the plasticizer and the inorganic filler has good water solubility, and handling properties such as waist strength of the film under high humidity. Is improved and process passability is improved. This is a PVA-based resin 1,2-glycol bond content of 1.8 mol% or more and a saponification degree of use and 92-9 6 mole% of the PVA-based resin, a specific amount of a plasticizer and a specific amount of the inorganic filler Was achieved.
The water-soluble film of the present invention makes use of the above characteristics, and is used for packaging various drugs such as dyes, detergents, agricultural chemicals, toilet cleaners, bathing agents, disinfectants, weakly acidic substances, weakly alkaline substances, and chlorinated substances, It can be used for conventionally known water-soluble film applications such as curved surface printing applications.

Claims (3)

1,2-glycol bond content of 1.8 mol% or more, consisting of saponification degree 92-9 100 parts by weight 6 mole% of the polyvinyl alcohol-based resin, plasticizer 20-50 parts by weight of an inorganic filler 1 to 20 parts by weight a water-soluble film, water-soluble film 20 ° C. for dissolution time in water is equal to or is Young's modulus of 1.5 kg / mm ² or more in 50 seconds or less. 1,2-glycol bond content of 1.8 mol% or more and a saponification degree of 92-9 6 mole percent with respect to polyvinyl alcohol resin 100 parts by weight, monosaccharide and / or polysaccharides 5-50 parts by weight formulation The water-soluble film according to claim 1.   The water-soluble film according to claim 2, wherein the polysaccharide is starch.