JPH0940834A - Polyvinyl alcohol film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyvinyl alcohol film comprising a polyvinyl alcohol(PVA) resin and a water-soluble sulfonic acid salt group-containing compound in a specific ratio, improved in dissolution speed in cold water, excellent in mechanical strength, water solubility and water dispersibility, and useful as a packaging material for agricultural chemicals, etc. SOLUTION: This polyvinyl alcohol film comprises (A) 100 pts.wt. of a PVA resin e.g. having an average polymerization degree of 300-4,000 and a saponification degree of >=70mol.% and (B) 1-100 pts.wt. of a water-soluble sulfonic acid salt group-containing compound such as sodium polystyrene sulfonate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyvinyl alcohol film which is easily soluble in cold water.

[0002]

2. Description of the Related Art Cold water easily soluble films are used for various packaging applications such as laundry detergents, insecticides, bleaching agents, and cleaning agents. Especially, the materials to be packaged are toxic or adhere to users. Or, it is used for packaging when a specified amount of use is required, and when used, it is put into water as it is without opening a specified amount of package to obtain an aqueous solution or dispersion of a specified amount of material to be packaged. be able to.

As described above, when the film is packaged with a film that is easily soluble in cold water, the water-soluble film dissolves or disperses in water quickly during use, which makes handling very easy. BACKGROUND ART Polyvinyl alcohol (hereinafter abbreviated as PVA) film has excellent features that a film is tough, has excellent transparency, and has good printability. Therefore, conventionally, a PVA film is often used as a water-soluble film. Has been.

[0004]

SUMMARY OF THE INVENTION However, PVA
The dissolution rate of the system resin has not been satisfactory for applications that require instantaneous dissolution in cold water.

In order to solve such problems, it is known to introduce various modifying groups into the PVA-based resin to make up for the above-mentioned drawbacks. JP-A-62-179550 and JP-A-4-17
It has been proposed in Japanese Patent Application Laid-Open No. 0405, Japanese Patent Application Laid-Open No. 4-114014, and Japanese Patent Application Laid-Open No. 5-59113.

However, in the conventional method as described above, it is necessary to introduce a large amount of modifying groups in order to obtain a cold water dissolution rate which can be satisfied at a practical level. When a large amount of the modifying group is introduced, there is a problem that the degree of polymerization becomes low and the mechanical strength required for the film cannot be obtained.

An object of the present invention is to provide a cold water easily soluble PVA film which is excellent in mechanical strength, inexpensive and easy to manufacture by blending a compound which is easily soluble in cold water.

[0008]

The PVA-based film of the present invention comprises a composition comprising a PVA-based resin and 1 to 100 parts by weight of a water-soluble sulfonate-containing compound based on 100 parts by weight of the PVA-based resin. It is characterized by becoming.

Hereinafter, the present invention will be described in detail.
The PVA resin used in the present invention has various degrees of polymerization,
It is possible to use those having a saponification degree. In terms of water solubility and mechanical properties of the film, the average degree of polymerization is particularly 300 to 400.
It is preferably 0 and the degree of saponification is 70 mol% or more.

The PVA resin used in the present invention may contain a small amount of other components in the molecule. Examples of such other components include (meth) acrylic acid, maleic acid, maleic anhydride, fumaric acid, crotonic acid, itaconic acid, and other carboxyl group-containing monomers or salts thereof, acrylamido-2-methylpropanesulfone. Acid soda,
Sulfonic acid group-containing monomers or salts thereof such as sodium allyl sulfonate and vinyl sulfonic acid, branched fatty acid vinyls such as vinyl pivalate and vinyl versatate, pyrrolidone-containing monomers such as vinylpyrrolidone, ethylene Α-olefins such as propylene, (meth) acrylic acid esters, acrylamide, dimethylacrylamide,
Amide group-containing monomers such as N-methylolacrylamide, N-vinyl-2-pyrrolidone, etc., alkyl vinyl ethers, silyl group-containing monomers such as trimethoxyl vinylsilane, allyl alcohol, dimethylallyl alcohol Le,
Hydroxyl group-containing monomers such as isopropenyl alcohol, allyl acetate, dimethylallyl acetate, acetyl group-containing monomers such as isopropenyl allyl acetate, halogen-containing monomers such as vinyl chloride and vinylidene chloride, styrene There is a method of saponifying a copolymer of vinyl acetate with an aromatic monomer such as. Particularly, a carboxyl group-containing monomer and a sulfonic acid group-containing monomer are preferable from the viewpoint of improving water solubility. Further, in the present invention, a PVA-based resin acetalized with an aldehyde such as formalin or butyraldehyde may be used.

The sulfonate-containing compound used in the present invention is a water-soluble compound containing a salt of sulfonic acid in the molecule and may be a low molecular weight compound or a high molecular weight compound, or
Both may be used together or either may be used. Examples of the sulfonate-containing compound include alkyl sulfonates, alkyl benzene sulfonates such as propylbenzene sulfonate soda and n-paraffin benzene sulfonate soda, isopropyl naphthalene sulfonate soda and butyl naphthalene sulfone. Alkyl naphthalene sulfonates such as acid soda, naphthalene sulfonate formalin polycondensates such as naphthalene sulfonic acid soda formalin polycondensate, melamine sulfone such as melamine sodium sulfonate formalin Acid salt formalin polycondensates, dialkyl sulfosuccinic acid ester salts such as di- (2-ethylhexyl) sulfosuccinic acid soda ester, alkyl sulfoacetic acid salts, N-acylmethyl taurines, allyl sulfonic acid soda α-Orefi Sulfonic acid salts, polymers of sulfonic acid-containing monomers such as polyethylene sulfonic acid soda, polyallyl sulfonic acid soda, and polystyrene sulfonic acid soda, and copolymers with other monomers. Examples thereof include polymers. In particular, a polymer is preferable in terms of preventing bleed-out of the sulfonate-containing compound. Of these, sodium polystyrene sulfonate is particularly preferable. The compound containing a sulfonate has good compatibility with the PVA-based resin, and when blended, it is mixed homogeneously and the water dissolution rate of the PVA-based resin can be remarkably improved.

The compounding amount of the sulfonate-containing compound is in the range of 1 to 100 parts by weight, preferably 5 to 80 parts by weight, based on 100 parts by weight of the PVA resin. If it is less than 1 part by weight, the effect of improving the water solubility cannot be sufficiently obtained. Also, if more than 100 parts by weight is blended,
The obtained film undergoes phase separation and becomes very brittle, so that practical mechanical strength cannot be obtained.

In the present invention, a plasticizer may be added in order to impart flexibility to the film. Examples of the plasticizer for PVA resin include glycerin, diglycerin, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, sorbitol, polyethylene glycol, trimethylolethane, trimethylolpropane, Pentaerythritol, 2,3-butanediol, 1,3-butanediol, polyhydric alcohols such as mannitol, amides such as dimethylacetamide, amines such as triethanolamine, dimethyl sulfoxide. And the like. Glycerin and diglycerin are preferred.

An antifoaming agent may be used in order to prevent foaming that occurs when the PVA resin is dissolved in water.
Any of the commercially available antifoaming agents for PVA-based resins that do not adversely affect the solubility of the film can be used. The amount of the defoaming agent is not particularly limited, and is usually used only in an amount necessary to prevent foaming of the PVA-based resin. Therefore, the compounding amount of the defoaming agent is P
1.0 part by weight or less is suitable for 100 parts by weight of the VA resin.

When a high degree of blocking resistance is required for the PVA-based resin film obtained by the method of the present invention, a slip agent and an antiblocking agent can be further added. By compounding these, it is possible to remarkably improve the disadvantage of the PVA-based resin film that it is easy to block under high temperature and high humidity.

The slip agent is added to form irregularities on the surface of the film and impart slipperiness to the obtained film. Examples thereof include calcium carbonate, alumina, apulgite, kaolin clay, silicon dioxide, calcium silicate,
Examples thereof include magnesium oxide, calcium carbonate, magnesium carbonate, barite, calcium sulfate, titanium dioxide, clay, talc, bentonite, wood flour, and starch. The amount of the slip agent blended is preferably 5 parts by weight or less with respect to 100 parts by weight of the PVA-based resin.

An antiblocking agent is added to prevent adhesion of the film surface after molding and facilitate opening.
What is generally commercially available may be used. For example, hydrocarbon having 12 to 30 carbon atoms, higher fatty acid, oxyfatty acid, fatty acid amide, alkylenebisfatty acid amide, fatty acid lower alcohol ester, fatty acid polyhydric alcohol ester, fatty acid polyglycol ester, fatty acid fatty alcohol ester, Examples thereof include fatty acid glycerin ester, fatty alcohol, and metallic soap.

Specific examples include paraffin wax, low-polymerization degree polyethylene, stearic acid, mystic acid, arachidic acid, behenic acid, stearylamide, palmitylamide, oleylamide, methylenebisstearamide and ethylenebisstear. Loamide, butyl stearate, hydrogenated castor oil, ethylene glycol monostearate, ethylene glycol monostearate, stearic acid monoglyceride, oleic acid monoglyceride, stearyl alcohol, cetyl alcohol, lead stearate, cadmium stearate, stearic acid. barium,
Examples thereof include calcium stearate and magnesium stearate. The mixing amount of the anti-blocking agent is preferably 2 parts by weight or less with respect to 100 parts by weight of the PVA resin.

The method for producing the film of the present invention is not particularly limited, and the film can be produced by a casting method, a melt extrusion method or the like. For example, a transparent and uniform film is obtained by simply forming an aqueous solution of a PVA-based resin and a sulfonate-containing compound, placing the solution on a smooth casting surface, and evaporating water and then peeling the solution from the casting surface. Is obtained. The casting surface is a smooth and hard material such as steel, aluminum, glass, polymer (for example, polyolefin, polyethylene, polyamide, polyvinyl chloride, polycarbonate, polyhalocarbon, etc.). Any of them will do. The evaporation rate of the aqueous solvent can be increased by heating the casting surface or exposing the deposited solution to heated air or infrared rays. The casting surface may be flat or made with a standard (drum type) industrial film casting machine and then
For example, it can be oven dried.

The thickness of the film is not particularly limited, but normally a film having a thickness of 5 to 200 μm is preferably used. Further, although the film shape may be smooth, the obtained film may be embossed by an embossing process or the like. The unevenness of the film is particularly effective in terms of “solubility in cold water” and “antiblocking property”.

In the present invention, PVA-based resin film is coated with P
Mixing not only with VA type resin alone but also with water-soluble or water-dispersible resin such as polyacrylic acid or its salt, cellulose such as polyacrylamide, hydroxypropyl cellulose, hydroxypropylmethyl cellulose and methyl cellulose Or mixed with other thermoplastic resins such as polyolefins such as polyethylene and polypropylene, nylon, polyester, polyvinyl chloride, polystyrene, polyvinyl butyral or ethylene-vinyl acetate copolymers and saponified products thereof. It is possible.

Since the film obtained in the present invention has a high dissolution rate in cold water, it is used as a packaging material for detergents, insecticides, bleaching agents, detergents, agricultural chemicals, bath agents, toiletry products and the like. .

[0023]

EXAMPLES Next, the present invention will be described more specifically with reference to examples.

The physical properties in the examples are measured by the methods described below. Evaluation method (uniformity) The state of the adjusted film was observed. Evaluation criteria ○: uniform ×: non-uniform (phase separation)

(Cold water dissolution time) The film, which had been conditioned at 20 ° C. and 65% RH for 24 hours, was cut into a size of 1 cm × 1 cm. This was immersed in distilled water at 5 ° C., and the time until the film was completely dissolved was measured.

(Film strength) 2 at 20 ° C. and 65% RH
The strength of the film after breaking for 4 hours was measured using Strograph R type manufactured by Toyo Seiki Co., Ltd. (Distance between chucks: 30 mm, pulling speed: 50 mm / min) (Comprehensive evaluation) Comprehensive evaluation of the obtained film Evaluation criteria ○: Good ×: There is a problem

Example 1 A 15% aqueous solution of PVA (reinforcement degree 88 mol%, average degree of polymerization 1850) was added with a 15% aqueous solution of allylsulfonic acid soda, and 100 parts by weight of PVA was added with allylsulfonic acid soda.
To 10 parts by weight, and sufficiently stirred to form a uniform solution. This aqueous solution was cast on a polyester plate having a smooth and horizontal surface using an applicator, and was oven dried to obtain a transparent and uniform film. The thickness of the obtained film was 30 μm.

The physical properties of the obtained film were evaluated by the above evaluation methods. The results measured in each evaluation are shown in Table 1.
Are shown together. The film had a sufficiently fast dissolution rate in cold water and a sufficient strength, and the result was good as a whole.

Example 2 A 15% aqueous solution of polystyrene sulfonic acid soda (average molecular weight 5000) was added to a 15% aqueous solution of PVA (saponification degree 88 mol%, average polymerization degree 1850), and polystyrene sulfonic acid soda was added to 100 parts by weight of PVA. -Add 10 parts by weight of the solution, and stir sufficiently to form a uniform solution. This aqueous solution was cast on a polyester plate having a smooth and horizontal surface using an applicator, and was oven dried to obtain a transparent and uniform film. The thickness of the obtained film is 30.
μm.

The physical properties of the obtained film were evaluated by the above evaluation methods. The results measured in each evaluation are shown in Table 1.
Are shown together. The film had a sufficiently fast dissolution rate in cold water and a sufficient strength, and the result was good as a whole.

Example 3 A 15% aqueous solution of polystyrene sulfonic acid soda (average molecular weight 5000) was added to a 15% aqueous solution of PVA (saponification degree 88 mol%, average polymerization degree 1850), and polystyrene sulfonate sodium was added to 100 parts by weight of PVA. -Adding to 80 parts by weight, the mixture was sufficiently stirred to form a uniform solution. This aqueous solution was cast on a polyester plate having a smooth and horizontal surface using an applicator, and was oven dried to obtain a transparent and uniform film. The thickness of the obtained film is 30.
μm.

The physical properties of the obtained film were evaluated by the above evaluation methods. The results measured in each evaluation are shown in Table 1.
Are shown together. The film had a sufficiently fast dissolution rate in cold water and a sufficient strength, and the result was good as a whole.

Example 4 A 15% aqueous solution of PVA (saponification degree: 93 mol%, average polymerization degree: 1300) was mixed with a 15% aqueous solution of allylsulfonic acid soda to 100 parts by weight of PVA.
50 parts by weight, and sufficiently stirred to form a uniform solution. This aqueous solution was cast on a polyester plate having a smooth and horizontal surface using an applicator, and was oven dried to obtain a transparent and uniform film. The thickness of the obtained film was 30 μm.

The physical properties of the obtained film were evaluated by the above evaluation methods. The results measured in each evaluation are shown in Table 1.
Are shown together. The film had a sufficiently fast dissolution rate in cold water and a sufficient strength, and the result was good as a whole.

Example 5 1 of PVA (saponification degree 82 mol%, average degree of polymerization 600)
To a 5% aqueous solution, a 15% aqueous solution of allylsulfonic acid was added, and 100 parts by weight of PVA was used to dissolve allylsulfonic acid.
5 parts by weight of the solution was added and sufficiently stirred to form a uniform solution. This aqueous solution was cast on a polyester plate having a smooth and horizontal surface using an applicator, and was oven dried to obtain a transparent and uniform film. The thickness of the obtained film was 30 μm.

The physical properties of the obtained film were evaluated by the above evaluation methods. The results measured in each evaluation are shown in Table 1.
Are shown together. The film had a sufficiently fast dissolution rate in cold water and a sufficient strength, and the result was good as a whole.

Example 6 1 of PVA (saponification degree 93 mol%, average degree of polymerization 600)
A 15% aqueous solution of polystyrene sulfonic acid soda (average molecular weight 5000) was added to a 5% aqueous solution so that 80 parts by weight of polystyrene sulfonic acid soda was added to 100 parts by weight of PVA, and sufficiently stirred to form a uniform solution. did. This aqueous solution was cast on a polyester plate having a smooth and horizontal surface using an applicator, and was oven dried to obtain a transparent and uniform film. The thickness of the obtained film is 30 μm
Met.

The physical properties of the obtained film were evaluated by the above evaluation methods. The results measured in each evaluation are shown in Table 1.
Are shown together. The film had a sufficiently fast dissolution rate in cold water and a sufficient strength, and the result was good as a whole.

Example 7 A 15% aqueous solution of PVA modified with maleic acid (saponification degree: 88 mol%, average polymerization degree: 1550, modification degree: 2 mol%) was added with 1 part of polystyrene sulfonic acid soda (average molecular weight: 5000).
A 5% aqueous solution was added so as to be 10 parts by weight of polystyrene sulfonate soda against 100 parts by weight of PVA, and sufficiently stirred to obtain a uniform solution. This aqueous solution was cast on a polyester plate having a smooth and horizontal surface using an applicator, and was oven dried to obtain a transparent and uniform film. The thickness of the obtained film was 30 μm.

The physical properties of the obtained film were evaluated by the above evaluation methods. The results measured in each evaluation are shown in Table 1.
Are shown together. The film had a sufficiently fast dissolution rate in cold water and a sufficient strength, and the result was good as a whole.

Comparative Example 1 A 15% aqueous solution of PVA (saponification degree 88 mol%, average degree of polymerization 1850) was cast on a polyester plate having a smooth surface and a horizontal surface by using an applicator, followed by oven drying. To obtain a transparent and uniform film. The thickness of the obtained film was 30 μm.

The physical properties of the obtained film were evaluated by the above evaluation methods. The results measured in each evaluation are shown in Table 1.
Are shown together. Since it dissolves in cold water at a high speed, it was a problem as a film easily soluble in cold water.

Comparative Example 2 A 15% aqueous solution of PVA (saponification degree: 88 mol%, average polymerization degree: 1850) was mixed with a 15% aqueous solution of sodium allylsulfonate so that 150 parts by weight of sodium allylsulfonate was added to 100 parts by weight of PVA. Then, the mixture was sufficiently stirred to form a uniform solution. This aqueous solution was cast on a polyester plate having a smooth and horizontal surface using an applicator, and was oven dried to obtain a film. The thickness of the obtained film was 30 μm.

The physical properties of the obtained film were evaluated by the above evaluation methods. The results measured in each evaluation are shown in Table 1.
Are shown together. It melted in cold water fast enough,
Phase separation occurred, the tackiness was exhibited, and the strength was very low, which was a problem in practical use.

Comparative Example 3 A 15% aqueous solution of polystyrene sulfonic acid soda (average molecular weight 5000) was added to a 15% aqueous solution of PVA (saponification degree 88 mol%, average polymerization degree 1850), and polystyrene sulfonate sodium was added to 100 parts by weight of PVA. -Adding to 150 parts by weight and thoroughly stirring to make a uniform solution. This aqueous solution was cast on a polyester plate having a smooth and horizontal surface using an applicator, and was oven dried to obtain a film. The thickness of the obtained film was 30 μm.

The physical properties of the obtained film were evaluated by the above evaluation methods. The results measured in each evaluation are shown in Table 1.
Are shown together. It melted in cold water fast enough,
Phase separation occurred and it became brittle even if it was non-uniform, and the strength required for practical use could not be obtained.

[0047]

[Table 1]

[0048]

EFFECT OF THE INVENTION The film of the present invention has a significantly improved dissolution rate of a PVA-based film in cold water by a simple and inexpensive method. Therefore, the film of the present invention is suitable for a water-soluble or water-dispersible solid packaging film,
In particular, it is suitable for applications in which it is necessary to dissolve instantly in cold water, which was insufficient in the dissolution rate of conventional PVA-based films.

Claims (1)

[Claims] 1. A polyvinyl alcohol resin and 1 to 100 parts by weight per 100 parts by weight of the polyvinyl alcohol resin.
A polyvinyl alcohol-based film, comprising a composition in which parts by weight of a water-soluble sulfonate-containing compound is blended.