JPH06184386A - Water-soluble thermoplastic film and its use - Google Patents

Abstract

PURPOSE:To prepare the subject film excellent in such properties as cold-water solubility, strength, alkali resistance, acid resistance, heat-sealability, and flexibility by blending poly(vinyl alcohol) with an N-vinylacetamide (co)polymer. CONSTITUTION:This film is made from a composition consisting substantially of poly(vinyl alcohol) (A) and an N-vinylacetamide polymer (B) which is either a homopolymer or a copolymer with a specific vinyl monomer (C), the ratio of the polymers (A) to (B) being about 1:1.5 to 10:1 by weight. Examples of the monomer (C) include compounds represented by the formula CH2=CH-O-CO- R1 (wherein R1 is a 1-4C alkyl) or CH2=C(R2)-COOR3 (wherein R2 is hydrogen or methyl and R3 is a 1-4C alkyl).

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a water-soluble thermoplastic film of polyvinyl alcohol and N-vinylacetamide polymer composition. More specifically, it is obtained by blending a substantially water-soluble polyvinyl alcohol with an N-vinylacetamide homopolymer or a copolymer of N-vinylacetamide and a vinyl-based monomer, easy solubility in cold water, alkali resistance, The present invention relates to a water-soluble thermoplastic film made of a compound having excellent acid resistance and mechanical strength, and its specific use.

BACKGROUND OF THE INVENTION Chemicals such as water-soluble pharmaceuticals, pesticides such as detergents, insecticides, herbicides and fungicides, dyes and pigments, etc. are in powder form in consideration of solubility and dispersibility. Although the product is packaged and sold in the market, the consumer may contact the powdered contents when opening the packaging material or measuring the contents, or the powder that has been scattered in the air may adhere to the mucous membranes of the trachea, etc. May adversely affect the surrounding environment. In addition, there is a problem that attention must be paid to the disposal processing of the packaging material after use in which the chemical remains. Therefore, in order to solve the problems associated with the use of the powdery product, a water-soluble film made of a water-soluble thermoplastic resin in which the packaging material itself is dissolved at the time of use is drawing attention.

[0003]

2. Description of the Related Art Conventionally, as a typical example of a water-soluble thermoplastic resin, polyvinyl alcohol (hereinafter abbreviated as PVA) obtained by hydrolyzing (saponifying) an acetoxy group of polyvinyl acetate with an acid or an alkali to form a hydroxyl group. .)It has been known. However, PVA has a saponification degree of 9
When it is higher than 5 mol%, crystallization progresses over time to become cold water insoluble, and when the saponification degree is lowered to 80 mol% or lower and the crystallinity is suppressed, the hydrophobicity becomes high and water becomes insoluble. That is, PVA is easily soluble in cold water when the saponification degree is in the range of 80 to 95 mol%, and becomes insoluble in water when the saponification degree is outside the range. Further, cold water easily soluble PVA having a saponification degree of 80 to 95 mol% is used as a molded product such as a packaging film,
When the object to be packaged is acidic or alkaline, PVA is rapidly hydrolyzed to increase the degree of saponification, so that it becomes insoluble in cold water. Further, PVA is crosslinked by heating during heat sealing and becomes insoluble in water.

In recent years, various studies have been conducted in order to solve the above problems in water solubility of PVA. For example, Japanese Examined Patent Publication (Kokoku) No. 42-20845 discloses a film, sheet and filament of PVA in which aldol acetalization is performed and which is easily soluble in cold water. However, since there are a hydroxyl group and an aldehyde group in the molecule of aldol, aldols may react with each other during the reaction with PVA, and there is a problem in controlling the reaction. This indicates that it is extremely difficult to industrially and stably produce an acetalized product of PVA having an acetalization degree capable of retaining water solubility for a long period of time. Further, a water-soluble resin composition prepared by blending PVA with another polymer has been proposed.
For example, Japanese Examined Patent Publication No. 43-1487 discloses a high degree of saponification PVA.
A composition comprising PVA (saponification degree of 97 mol% or more), low saponification degree PVA (saponification degree of 75 to 92 mol%), and starch is disclosed in JP-A-57-12540 as P having a saponification degree of 80 to 95 mol%.
A blend of VA and polyacrylic acid having a molecular weight of 30,000 to 40,000 and low molecular weight PVA in JP-A-53-24351.
And a medium molecular weight PVA (all having a saponification degree of 85 to 90 mol%) and an ethylenically unsaturated group-containing alkyl ester (for example, an acrylic acid alkyl ester or a methacrylic acid alkyl ester) polyethylene glycol are disclosed. Since all the resin components are unstable with respect to the alkaline component, the phenomenon of insolubility in cold water due to the progress of hydrolysis is unavoidable. Further, PVA has a poor compatibility with these water-soluble resins, and therefore the film strength is often remarkably lowered after blending with other resins.

Further, a composition in which PVA is modified with an unsaturated carboxylic acid has been proposed (application and market of water-soluble polymer, CMC Publishing Co., Ltd.), but the contact with an acidic substance impairs the easy solubility in cold water. On the other hand, N-vinylacetamide (hereinafter abbreviated as NVA) homopolymer, copolymer, or a composition containing these is known.

For example, as a composition containing a polymer of NVA, a photosensitive resin composition containing NVA and containing PVA as a main component (JP-A-58-21736), an adhesive aqueous polymer dispersion ( JP-A-58-5361) is disclosed.
Further, a thermoplastic cold water-soluble film and a molded product (Nippon Sho 60-228551) using N-vinyl-N-methylacetamide which is a homologous compound of NVA and PVA are disclosed.

As a copolymer of NVA and its homologous compound, a secondary N-vinylcarboxylic acid amide and an olefinic unsaturated compound for moldings and fibers (Japanese Patent Laid-Open No. 45-2).
No. 3356), a copolymer of NVA for a dispersant and an ethylenically unsaturated compound containing a perfluoroalkyl group (Japanese Patent Application Laid-Open No. Sho 63-242242).
63-186713), copolymers of NVA and vinyl monomers such as acrylic acid esters as fluidity improvers for recovering crude oil (JP-A-52-85286, JP-A-58-217058, JP-A-58-217058,
59-86614 publication) and the like have been proposed.

However, a film composed of a composition of NVA (co) polymer and PVA which can be applied to a water-soluble packaging substrate has not been known so far.

[0009]

Therefore, the object of the present invention is to increase the crystallinity which causes PVA to become insoluble in cold water.
To provide a water-soluble thermoplastic film which is suppressed by the addition of an NVA copolymer having good compatibility with VA and is excellent in properties such as easy solubility in cold water, strength, alkali resistance, acid resistance, heat sealability and flexibility. is there.

[0010]

As a component of a water-soluble resin, the present inventor has found that N- which is excellent in alkali resistance and acid resistance.
Focusing on the (co) polymer of vinylacetamide, the inventors have invented blending the (co) polymer of NVA with PVA. NV
The polymer of A has excellent compatibility with PVA, and NVA is added to PVA.
It was considered that the crystallization of PVA was suppressed and the acid resistance and the alkali resistance were imparted by blending the polymer. As a result of earnest research, specific PVA and NVA
The inventors have found that a composition comprising a homopolymer or a copolymer of NVA and a specific vinyl monomer can solve the above-mentioned various drawbacks of the PVA resin, and have completed the present invention.

That is, the present invention is as follows: 1) Substantially PVA and NVA homopolymer or NV
A water-soluble thermoplastic film comprising a composition obtained by blending a copolymer of A and a specific vinyl monomer. 2) A water-soluble thermoplastic film in which PVA is a water-soluble PVA having a saponification degree of 80 to 95 mol%. 3) NVA homopolymer or NVA blended with PVA
And the ratio of the copolymer composed of the specific vinyl monomer is PVA: NVA (co) polymer = 1: 1.5 to 1 in weight ratio.
A water soluble thermoplastic film which is 0: 1. 4) The ratio of the vinyl-based monomer copolymerized with NVA is N
Within the range of 35% by weight or more and 100% by weight or less of VA and 0% by weight or more and 65% by weight or less of vinyl monomer, PV
A film showing water solubility and thermoplasticity when blended with A. 5) The vinyl-based monomer copolymerizable with NVA according to the above 1) is represented by the general formula (I) CH ₂ ═CH—O—CO—R ₁ (I) (wherein R ₁ is a C _{1 to} C ₄ lower group). Represents an alkyl group.)
A compound of formula (II) CH ₂ ═C (R ₂ ) —COOR ₃ (II) (wherein R ₂ represents hydrogen or a methyl group, and R ₃ represents C ₁
To C ₄ lower alkyl groups. ) A compound represented by
General formula (III)

[Chemical 2] (In the formula, R ₄ and R ₅ represent hydrogen or a methyl group, and R ₆
Represents hydrogen or a C ₁ -C ₄ lower alkyl group or a phenyl group. Moreover, n represents the integer of 1-100. Compounds represented by), the general formula _{(IV) CH 2 = CH-} CO-R 7 (IV) ( wherein, R ₇ represents a lower alkyl group of C ₁ -C _4.)
In the compound represented by the general formula _{(V) CH 2 = CH-} CO-N (R 8) R 8 '(V) ( wherein, R ₈ and R _8' lower alkyl group is hydrogen or C ₁ -C ₄ Wherein R ₈ and R ₈ ′ are not hydrogen at the same time), a compound of the general formula (VI) CH ₂ ═CH—O—R ₉ (VI) (wherein R ₉ is C It refers to lower alkyl groups ₁ -C _4.)
A water-soluble thermoplastic film which is one or more compounds selected from the compounds represented by: 6) The present invention relates to uses for a water-soluble packaging material, a seed tape substrate, a special printing substrate, etc., which is characterized by comprising the water-soluble thermoplastic film described in 1) above.

(Structure of the Invention) The present invention will be described in detail below. PVA PVA requires a rapid solubility in cold water, so the degree of saponification is 80-95 mol% partially saponified PVA.
Is preferred. When the degree of saponification is less than 80 mol%, the hydrophobicity is strong, and when the degree of saponification is higher than 95 mol%, the degree of crystallinity is high and the water becomes insoluble in cold water. The average degree of polymerization is closely related to the strength of the molded product and the solubility in water. If the degree of polymerization is too low, the molded product will not have sufficient strength, and if the degree of polymerization is too high, the dissolution rate in water will decrease. Therefore, the range of 100 to 4,000 is good, preferably 300 to 3,500, and more preferably 500 to
It is 3,000.

[0013] NVA polymer formulated into NVA PVA while maintaining the water-soluble with the PVA, to suppress crystallization of the PVA, acid resistance of PVA, improving the alkali resistance. The content of NVA in the NVA-based polymer depends on the degree of saponification of PVA, the degree of polymerization, NV
The amount is preferably 35% by weight or more and 100% by weight or less, though it depends on the type and composition ratio of the vinyl-based monomer of the A copolymer.
If the amount is 5% by weight or less, sufficient water solubility, alkali resistance, acid resistance, and compatibility with PVA cannot often be obtained.

Vinyl Monomer The vinyl monomer in the NVA polymer lowers the softening point of the graft polymer as compared with the case of blending the NVA homopolymer, and improves tensile elongation and heat sealability.
As a result, the amount of external plasticizer such as glycerin added can be reduced, and adverse effects such as bleeding caused by the large amount of external plasticizer added can be suppressed.

Next, specific examples of such vinyl monomers will be described, but it goes without saying that the vinyl monomers are not limited to these. As the compound represented by the general formula (I),
Examples thereof include vinyl acetate, vinyl propionate, vinyl butyrate and vinyl isobutyrate, with vinyl acetate being preferred.

Examples of the compound represented by the general formula (II) include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, and (meth). ) Isobutyl acrylate, sec-butyl (meth) acrylate, t-butyl (meth) acrylate and the like can be mentioned, with preference given to methyl acrylate and ethyl acrylate.

As the compound represented by the general formula (III),
Polyethylene glycol (meth) acrylate, (meth)
Polypropylene glycol acrylate, Polyethylene glycol methacrylate Polypropylene glycol, 2-Methoxyethyl acrylate, 2-Butoxyethyl acrylate, Ethoxydiethylene glycol acrylate, Methoxytriethylene glycol acrylate, Methoxydipropylene glycol acrylate, Phenoxypolyethylene glycol acrylate Examples thereof include methoxypolyethylene glycol (meth) acrylate, methoxydiethylene glycol methacrylate, and 2-phenoxyethyl methacrylate, and preferably polyethylene glycol (meth) acrylate, 2-methoxyethyl acrylate, ethoxydiethylene glycol acrylate, and acrylic. Acid methoxytriethylene glycol, (meth) acrylic acid methoxypolyethylene Glycol.

As the compound represented by the general formula (IV),
For example, methyl vinyl ketone, ethyl vinyl ketone, n
-Propyl vinyl ketone, isopropyl vinyl ketone,
Examples thereof include t-butyl vinyl ketone, isobutyl vinyl ketone, and the like, with preference given to methyl vinyl ketone and ethyl vinyl ketone.

As the compound represented by the general formula (V), for example, N-methyl acrylamide, N-ethyl acrylamide, N-isopropyl acrylamide, Nn-butyl acrylamide, N-sec-butyl acrylamide, N-isobutyl acrylamide, Nt-butyl acrylamide, N, N-dimethyl acrylamide, N,
N-diethyl acrylamide, N, N-di-n-butyl acrylamide, N, N-diisobutyl acrylamide and the like can be mentioned, but N, N-dimethyl acrylamide and N, N-diethyl acrylamide are preferable.

Examples of the compound represented by the general formula (VI) include methyl vinyl ether, ethyl vinyl ether,
Examples thereof include n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, sec-butyl vinyl ether, t-butyl vinyl ether, and the like, with preference given to methyl vinyl ether and ethyl vinyl ether.

Other than the above vinyl-based monomers, if a copolymer with NVA within the range of the composition described in the claims can obtain a copolymer having water-soluble and thermoplastic properties, it can be used. can do. These vinyl-based monomers may be used alone or in combination of two or more at the time of copolymerization.

In the present invention, the blending ratio of the vinyl-based monomer and NVA varies depending on the kind of the vinyl-based monomer, but it may be a ratio such that the obtained polymer exhibits water solubility and thermoplasticity, and generally, NVA: vinyl-based monomer = 35 to 100% by weight: 65 to 0% by weight. When the proportion of NVA is less than 35% by weight (when the vinyl-based monomer exceeds 65% by weight), it becomes insoluble in water.

The blending ratio of each vinyl monomer according to the present invention will be described below. Formulas (I), (II),
In the case of the vinyl monomers represented by (IV), (V) and (VI), it is 0 to 65% by weight, preferably 20 to 50% by weight when the substituting lower alkyl group is C _{1 to} C ₂ . When the lower alkyl group is C _{3 to} C ₄ , it is 0 to 25% by weight, preferably 5 to 20% by weight, and the above general formula (II
In the case of the vinyl-based monomer represented by I), the content is 0 to 65% by weight, preferably 20 to 60% by weight. When two or more vinyl-based monomers represented by the general formulas (I) to (IV) are used in combination, The amount is generally 0 to 65% by weight, preferably 20 to 60% by weight, although it depends on the kind of the vinyl-based monomer.

Polymerization conditions for NVA-based polymer (1) Polymerization method The polymerization method for producing the NVA-based polymer to be blended with the PVA of the present invention is not particularly limited, but radical polymerization is preferred.
As the radical polymerization, any of solution polymerization, precipitation polymerization, bulk polymerization, reverse phase suspension polymerization and the like can be used, but from the viewpoint of reaction control, water or a mixed solvent of water and a suitable organic solvent soluble in water is used. Solution polymerization is carried out by dissolving the monomer and radical polymerization initiator and raising the temperature to the reaction start temperature, precipitation polymerization in which the polymer produced by the same method is precipitated using an insoluble organic solvent, monomer in water Is dissolved, and this aqueous solution is dispersed and suspended in an appropriate organic solvent,
Reversed phase suspension polymerization is preferably carried out by adding a radical polymerization initiator and raising the temperature to the reaction temperature.

(2) Radical Polymerization Initiator The polymerization initiator can be selected from peroxide type, azobis type and redox type depending on the solubility in the polymerization solvent used. As such a polymerization initiator,
Hydrogen peroxide, t-butylperoxymaleic acid, succinic acid peroxide, benzoyl peroxide, lauroyl peroxide, acetyl peroxide, etc. in peroxide type, 2,2'-azobisisobutyronitrile in azobis type, 2,2'-azobis (2-aminodipropane) dihydrochloride, 2,2'-azobis [2-methyl-N- (hydroxymethyl) propionamide], etc. In the redox system, ammonium persulfate, potassium persulfate, etc. Can be mentioned.

The amount of the initiator used is 0.
Although it can be arbitrarily selected in the range of 001 to 5% by weight, it is preferably 0.005 to 3% by weight, particularly preferably 0.01 to 2% by weight. When the amount of the initiator exceeds 5% by weight, the reaction proceeds rapidly and it becomes difficult to control the reaction.
Further, if it is less than 0.001% by weight, the amount is too small and the yield may be lowered.

(3) Polymerization solvent The solvent used in the polymerization reaction can be used without any particular limitation as long as it can dissolve the vinyl monomer used with NVA without inhibiting radical polymerization. As such a solvent, water, an organic solvent such as isopropyl ether, dioxane, tetrahydrofuran, ethylene glycol dimethyl ether, ether such as diethylene glycol dimethyl ether, methyl acetate, ethyl acetate, isopropyl acetate, butyl acetate, ester such as isoamyl acetate, acetone, Examples thereof include ketone systems such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, aromatic systems such as xylene and toluene, and alkyl amide systems such as dimethylformamide and dimethylacetamide. These solvents may be used alone or in combination of two or more kinds. Particularly preferred solvents include water, tetrahydrofuran, dioxane, diethylene glycol dimethyl ether, acetone, methyl ethyl ketone, ethyl acetate and the like. In the case of reverse phase suspension polymerization, water is used as a solvent, and an aliphatic hydrocarbon organic solvent such as heptane or cyclohexane is used as a dispersion medium.

(4) Monomer Concentration The monomer concentration at the time of polymerization can be arbitrarily selected by the polymerization method. However, in the case of solution polymerization, precipitation polymerization, and reverse phase suspension polymerization, if the concentration of the monomer exceeds 50% by weight, the reaction will proceed rapidly and it will be difficult to control the reaction. Further, if it is less than 5% by weight, the reaction time is too long, the yield per reaction is small, and the production efficiency is deteriorated. Therefore, it is 5 to 50% by weight, preferably 10 to 40% by weight. In the case of reverse phase suspension polymerization, the aqueous monomer solution is suspended in an aliphatic hydrocarbon organic solvent, but the amount of the aliphatic hydrocarbon solvent used is 0.3 times although it depends on the concentration of the aqueous monomer solution. If it is less than 10 times, it becomes difficult to control the reaction, and if it exceeds 10 times, the production efficiency is deteriorated. Therefore, it is preferably 0.3 to 10 times, preferably 0.5 to 5 times the aqueous monomer solution.

(5) Polymerization temperature and polymerization time The polymerization temperature and the polymerization time can be arbitrarily selected depending on the type of the monomer and the polymerization initiator to be used. The boiling point is preferable, and the polymerization time is preferably 1 to 8 hours from the viewpoint of production efficiency.

The polymer molecule thus obtained is
NVA and vinyl monomers other than NVA, or NV
It is considered that only A has a linear structure in which it is randomly arranged, and a part thereof has a branched structure. The degree of polymerization is closely related to the solubility of the polymer in water, the strength of the molded article, and the compatibility of PVA. If the degree of polymerization is too high, it becomes difficult to dissolve in water, the compatibility becomes poor, and the strength of the molded article also increases. descend. If the degree of polymerization is too low, the molded product will not have sufficient strength. Therefore, the average degree of polymerization of NVA polymer is 20.
100 to 100,000, preferably 50 to 10,000, and more preferably 100 to 1,000.

Mixing ratio of PVA and NVA-based polymer Since the mixing ratio of PVA and NVA-based polymer depends mainly on PVA, the crystallization rate of PVA, acid resistance, alkali resistance, and strength of the molded product are mainly determined. It is closely related to the strength of the molded product. If the blending amount of the NVA-based polymer is too small, the crystallization rate will be high, and the acid resistance and alkali resistance will also be reduced, so that it tends to be insoluble in cold water. On the other hand, if the amount of the NVA polymer is too large, the strength of the molded product will decrease. Therefore, the compounding ratio is PVA: NVA polymer = 10: 1 to 1: 1.5, preferably 10: 2 to 1: 1 and particularly preferably 10: 3 to.
It is 1: 0.8. Moreover, the type of NVA polymer to be blended may be one type, or two or more types may be used in combination.

Molding Method Next, a method of molding the above-mentioned compound will be described. The NVA polymer after the polymerization reaction becomes a high-viscosity liquid, agar-like, salary-like, or polymer dispersion liquid. The solvent may be desolvated to form pellets, PVA pellets or powder, and a plasticizer may be added, and the mixture may be melted by heating, kneaded, and then molded into a film by using a molding machine.
Add water to VA, dissolve with stirring, and then cast the solution as it is.
The film may be formed by a ring method. As the heat molding method, a general extrusion molding method can be applied, and the T die method,
The inflation method and the like are exemplified. Molding temperature is 50
Although it can be arbitrarily selected from the range of ~ 230 ° C,
It is preferable to carry out at a temperature higher than the softening point of the PVA and NVA copolymer.

Further, a plasticizer for imparting flexibility during molding may be added. Examples of such plasticizers include glycerin, trimethylolpropane, polyethylene glycol (molecular weight of 1500 or less), polyglycerol, and the like. If desired, a water-soluble dye or pigment for coloring may be added.

[0034]

The water-soluble thermoplastic film of the present invention has little change in its chemical and physical properties even after being stored for a long time.
Solubility in water is unlikely to change, PVA has high film strength, and NVA has excellent alkali resistance and acid resistance. Therefore, it can be used for many purposes by making full use of its characteristics. Specifically, for packaging materials such as detergents, agricultural chemicals, dyes, industrial chemicals, water treatment agents, individual packaging of sanitary goods such as napkins, leak-proof membranes for napkins, hospital laundry bags, seed tape substrates, special printing, etc. It can be preferably used.

(Use) (1) Packaging materials for detergents, agricultural chemicals, etc. Powder detergents (mainly containing surfactants, builders, bleaching agents, enzymes, etc.) are used in small sachets for each dose (20-40g). It can be packaged and then put into water in a washing machine and dissolved before use. Therefore, the film thickness of the powder detergent film is preferably 15 to 50 μm in order to satisfy the mechanical strength and the dissolution rate. Since the detergent exhibits alkalinity, the composition of the present invention containing an alkali resistant NVA as a component is suitable for this purpose. By using it as a packaging material for powder detergent, it can be used without directly touching the contents,
Pre-measurement has advantages such as rationalization of dissolution operation and optimization of usage amount, and no need to worry about processing of packaging material after use.

When used as a packing material for agricultural chemicals, it is used as a packing material for wettable powders and water solvents. Examples of the target pesticides include insecticides, fungicides, herbicides, acaricides and the like. In general, pesticides are finely pulverized and therefore scatter when opened, which adversely affects the skin and respiratory system. However, packaging with a water-soluble film can prevent scattering.

(2) Hospital laundry bag A water-soluble film bag is immediately sealed and packed with contaminated equipment, clothes, sheets, etc. in the hospital at the place of occurrence, and sent to the laundry facility as it is to spread the pathogenic bacteria in the hospital. Suppressed and can prevent secondary infection. When the water-soluble film is used as a laundry bag for a hospital, it should be water-insoluble at room temperature and water-soluble in warm water (55-60 ° C),
Appropriate conditions include high wetting strength and that bags are not broken during normal handling.

(3) Substrate for seed tape: Seeds of vegetables such as Japanese radish, burdock root, carrot, spinach, flowers and the like are arranged at regular intervals on a water-soluble film tape, and the tape is wrapped so as to wrap the seeds. The thread can be wound on a spiral to fix the seeds, or the seeds can be arranged between two tapes of this film and the film can be fused and fixed for use. Further, the tape may be mixed with nutrient components of plants. It can be used as a suitable means for planting seeds at equal intervals by arranging tapes in a field in a straight line, covering with soil, and spraying water to dissolve the film. At the time of weeding, it is important to sow the seeds in a straight line from the workability at the time of harvesting or to sow the seeds at regular intervals from the surface of plant growth, but by using tape,
Well, this sowing can be done easily without effort.

(4) Special printing The water-soluble film on which the pattern is printed is floated on the liquid with the printing surface facing up, and then the object to be printed is pressed and the pattern is printed by hydraulic pressure. This printing can be used for building materials, aluminum sashes, woodworking products, office equipment, stone materials, etc., and the film after printing can be removed by washing with water.

Further, when a water-soluble film is printed with a hydrophobic ink and the difference between the non-hydrophilicity of the printed portion and the hydrophilicity of the non-printed portion causes a large difference in stretchability when wet with water.
By utilizing this property, it is possible to make an uneven surface according to the printing pattern on uncured plaster, cement surface, etc., and use it for wall decoration of buildings. This film is highly stretchable due to wetting, requires a force for deeply digging a plaster surface and the like, and has a shape-retaining force, and is suitable for printing those having irregularities and irregularities.

Further, it can be applied to a screen printing film in a manufacturing process of a printed board, a flexible board, a touch panel and the like in the field of electronic industry.

[0042]

[Examples] Hereinafter, the water-soluble thermoplastic film will be described in more detail with reference to examples and usage examples, but the present invention is not limited to the following examples.

Preparation of NVA-based polymer Polymers 1, 6, 7, 12, 14 to 18 NVA and vinyl-based monomer having the composition shown in Table 1, 300 g of water as a solvent, and 100 g of dioxane are stirred with a nitrogen introducing pipe. Then, the mixture was charged into a 1-liter four-necked flask equipped with a condenser, and 0.10 g of 2,2'-azobis (2-amidinopropane) dihydrochloride as a polymerization initiator was added under a nitrogen atmosphere, and the temperature shown in Table 1 was obtained. The temperature was raised. After polymerizing at that temperature for a predetermined time, the mixture was allowed to cool, and about 2 liters of water was added to the agar-like polymerization solution to dissolve it. Pour this into about 10 liters of acetone and NVA
The system polymer was precipitated and purified, and dried to obtain the NVA polymer in the yield shown in Table 1.

Polymers 2, 5, 10, 11, 13, 19 NVA and vinyl-based monomer having the composition shown in Table 1 and 400 g of water as a solvent were equipped with a stirrer, a nitrogen inlet pipe, and a cooler.
The mixture was placed in a 4-liter four-necked flask, and 0.10 g of a polymerization initiator 2,2'-azobis (2-amidinopropane) dihydrochloride was added under a nitrogen atmosphere, and the temperature was raised to the temperature shown in Table 1. After polymerizing at that temperature for a predetermined time, the mixture was allowed to cool, and about 2 liters of water was added to the agar-like polymerization solution to dissolve it. This was poured into about 10 liters of acetone to precipitate and purify the NVA-based polymer, which was then dried to obtain the NVA-based polymer in the yields shown in Table 1.

Polymers 3, 4, and 20 NVA, a vinyl-based monomer having the composition shown in Table 1, and 400 g of dioxane as a solvent were charged into a 1-liter four-necked flask equipped with a stirrer, a nitrogen inlet tube, and a condenser. Then, 2,2'-azobisisobutyronitrile (0.10 g or 0.20 g) as a polymerization initiator was added in a nitrogen atmosphere, the temperature was raised to the temperature shown in Table 1, and the polymerization was carried out at that temperature for a predetermined time. During the reaction, the polymer was precipitated and the polymerization solution became salary. After the reaction, the mixture is allowed to cool, and the formed precipitate is filtered, washed, and dried,
The yield of NVA polymer shown in Table 1 was obtained.

Polymers 8 and 9 NVA and n-butyl vinyl ether having the composition shown in Table 1 and 400 g of dioxane as a solvent were stirred, a nitrogen introducing tube,
Charge a 1 liter four-necked flask equipped with a condenser,
Lauroyl peroxide as a polymerization initiator under nitrogen atmosphere 0.
50 g) was added, the temperature was raised to 70 ° C., and polymerization was carried out at that temperature for 5 hours. During the reaction, the polymer was precipitated and the polymerization solution became salary. After the reaction, the mixture was allowed to cool, and the formed precipitate was filtered, washed, and dried to obtain an NVA polymer in the yield shown in Table 1.

Polymer 21 NVA (50 g) was dissolved in water (150 g), and a dispersion aid, hydroxyethyl cellulose (1.0 g), was dissolved in a four-necked flask equipped with a stirrer, a nitrogen inlet tube, and a condenser. 1.
The NVA aqueous solution was dispersed in 200 g of heptane in which 0 g of Rheodor SP-S10 (manufactured by Kao Corporation) was dissolved while stirring. 2,2 '-(N, N' of polymerization initiator under nitrogen atmosphere
-Dimethyleneisobutylamidine) dihydrochloride (0.05 g) was added, and polymerization was started at 35 ° C. After polymerizing for 6 hours, the mixture was allowed to cool, and the polymer solution was filtered and dried to obtain 47 g of NVA homopolymer.

[0048]

[Table 1]

(Film molding) NVA-based polymers 1 to 21
5% aqueous solution of PVA (polymerization degree 1000 to 1500, saponification degree 87 to 89 mol% PVA and polymerization degree 1700 to 24)
00, a 10% aqueous solution having a saponification degree of 87-89 mol% PVA) was mixed in the composition shown in the second chart, and after thoroughly stirring, the thickness of each of Examples 1-21 and Comparative Examples 1-6 was about 30 μm by the casting method. I got a film of. The degree of polymerization is 100
0-1500, saponification degree 87-89 mol% PVA and degree of polymerization 1700-2400, saponification degree 87-89 mol% PV
A 10% aqueous solution of A was similarly cast to obtain films of Comparative Examples 7 and 8 having a thickness of about 30 μm.

(Water solubility test) 3 at 20 ° C., 60% RH
The films of Examples 1 to 21 and Comparative Examples 1 to 8 stored for months were sandwiched between two paperboards having a hole of 3 × 3 cm and fixed with a stapler. Immerse this in distilled water at 20 ℃,
The dissolution state of the film was tested. The results are shown in Table 2.

(Heat Sealing Test) The films of Examples 1 to 21 and Comparative Examples 1 to 8 having a size of 5 × 5 cm were conditioned at 20 ° C. and 60% RH overnight, and then the same type of film was prepared. Two sheets were stacked and heat-sealed for 1 second with a heat sealer heated to 160 ° C. The results are shown in Table 2.
Shown in.

[0052]

[Table 2]

(Molding of Film Used) Examples 1 to 21,
An aqueous solution of the composition of Comparative Examples 1, 4, 5, 7, and 8 and a plasticizer were mixed in the composition shown in Table 3, stirred well, and used films 1 to 2 having a thickness of 18 μm and 30 μm by the casting method.
1. Comparative films 1, 4, 5, 7, and 8 having a film thickness of 30 μm were obtained.

[0054]

[Table 3]

(Film Tensile Test) Films used 1, 3, 4, 6, 8, 10, 12, 14, 15, 16,
19, 21, comparative films 1, 4, 5, 7, 8 (30 μ
m) cut into a size of 15 x 1.7 cm, 20 ° C, R
After humidity control at H60% for 7 days, Tensilon PTM-1
00 (manufactured by Orientec Co., Ltd.) was used to perform a tensile test at a tensile speed of 50 mm / min to measure the tensile stress at tensile break and the elongation at tensile break. The results are shown in Table 4.

[0056]

[Table 4]

Example of use 1: Detergent water-soluble packaging material Water-solubility test for packaging materials Powdered detergent (Attack: registered trademark manufactured by Kao Corporation) 1 g
Used films 1, 3, 5, 7, obtained by molding
9, 11, 13, 15, 17, 19, 21 (30 μm)
Using the comparative films 7 and 8, the unit packaging detergent was prepared by packaging with a heat sealer so as to have a size of 4 × 4 cm. The following tests were conducted using this unit packaging detergent.

Unit packing detergent for 3 months at 20 ° C., RH60
%, The contents were taken out after storage in a thermostatic chamber. The packaging material portion was poured into 3 liters of tap water (15 ° C.) gently stirred with a magnetic stirrer, and after 10 minutes, the presence or absence of an undissolved portion was visually determined. The results are shown in Table 5.

Solubility test of unit packaging detergent Powder detergent (Attack: registered trademark, manufactured by Kao Corporation) 20
used films 1, 3, 5, 7, obtained by molding g above
9, 11, 13, 15, 17, 19, 21 (30 μm)
The comparative films 7 and 8 were packaged with a heat sealer so as to have a size of 16 × 8 cm, and the solubility of the packaging detergent was tested. In the test, 30 liters of tap water at 15 ° C was put in a washing machine (Shizu Gozen: registered trademark) manufactured by Hitachi, Ltd., the above-mentioned unit packaging material was put therein, and the mixture was stirred for 5 minutes by weak inversion, then drained, and the foam was scraped off. , Visually determined.
The results are shown in Table 5.

[0060]

[Table 5]

Use Example 2: Water-soluble packaging material for agricultural chemicals Sumithion (registered trademark) [2-chloro-4,6-
2 g of the bis (ethylamino) -1,3,5-triazine] wettable powder obtained by molding as described above, used films 2, 4,
6, 8, 10, 12, 14, 16, 18, 20 (30μ
m) and Comparative Films 7 and 8 were heat-sealed to a size of 6 × 3 cm to prepare an agricultural chemical packaging agent. Further, with respect to 2 g of commercially available manzeb (zinc coordinated ethylene bisdithiocarbamic acid manganese salt) wettable powder, a pesticide packaging material was prepared in the same manner.

The agricultural chemical packaging thus obtained was stored in a thermostatic chamber at 20 ° C. and RH 60% for 3 months. After saving,
The contents, Sumithion wettable powder and Manzeb wettable powder, were taken out, and the film was put into 1 liter of water at 15 ° C which was gently stirred with a magnetic stirrer, and after 10 minutes, the presence or absence of undissolved substances was visually observed. It was judged. The results are shown in Table 6.

[0063]

[Table 6]

Use Example 3: Base material for seed tape , used films 1 and 1 adjusted to a length of 25 m and a width of 3 cm
25cm of radish seeds between 2 pieces of 0, 16 (18μm)
A seed tape was prepared by arranging one grain at intervals and welding and fixing 100 strains. This seed tape was sown on a test farm, and the germination rate of radish was examined 7 days later. Also, as a control, use 1 seed of radish seeds at intervals of 25 cm without using seed tape.
00 strains were sowed (control group), the germination rates were compared, and the effect of the water-soluble tape on germination was examined. Also, 67 after sowing
The root growth of daikon radish after the passage of time was compared. The results are shown in Table 7.

[0065]

[Table 7]

Use Example 4: Transfer Printing Sheet Films 3 and 1 used in size of 20 × 20 cm
Using 2, 14, 20 (30 μm), a desired pattern was printed on the film by using an oily thermoplastic ink (black) to prepare a transfer sheet. With the printed surface of the transfer sheet placed on the paper, the paper surface was placed on a hot plate of 80 ° C. with the paper surface facing downward, and the printed surface was lightly pressed two or three times with the hand to bring the film into close contact with the paper. . This was immersed in 5 liters of tap water at 30 ° C. for 3 minutes, then taken out, washed with water, and visually confirmed whether the transferability was good or bad. The results are shown in Table 8.

[0067]

[Table 8]

Front page continuation (72) Inventor Kazuhiko Oga 5-1 Ogimachi, Kawasaki-ku, Kawasaki-shi, Kanagawa Showa Denko K.K.

Claims (8)

[Claims] 1. A water-soluble thermoplastic film comprising a composition obtained by substantially blending polyvinyl alcohol and an N-vinylacetamide homopolymer or a copolymer of N-vinylacetamide and a specific vinyl monomer. 2. The degree of saponification of polyvinyl alcohol is 80 to
The water-soluble thermoplastic film according to claim 1, which is a water-soluble polyvinyl alcohol in the range of 95 mol%. 3. A blending ratio of an N-vinylacetamide homopolymer to be blended with polyvinyl alcohol or a copolymer of N-vinylacetamide and a vinyl monomer is 1: 1.5 to 10: 1 by weight. Item 2. A water-soluble thermoplastic film according to item 1. 4. The ratio of the vinyl-based monomer copolymerizable with N-vinylacetamide is N-vinylacetamide 35.
The water-soluble thermoplastic film according to claim 1, which exhibits water solubility and thermoplasticity when blended with polyvinyl alcohol within a range of from 100% by weight to 100% by weight and from 0% by weight to 65% by weight of a vinyl-based monomer. 5. A vinyl-based monomer copolymerizable with N-vinylacetamide is represented by the general formula (I) CH ₂ ═CH—O—CO—R ₁ (I) (wherein R ₁ is C _{1 to} C ₄ ). Represents a lower alkyl group.)
A compound of formula (II) CH ₂ ═C (R ₂ ) —COOR ₃ (II) (wherein R ₂ represents hydrogen or a methyl group, and R ₃ represents C ₁
To C ₄ lower alkyl groups. ) A compound represented by
General formula (III): (In the formula, R ₄ and R ₅ represent hydrogen or a methyl group, and R ₆
Represents hydrogen, a C ₁ -C ₄ lower alkyl group or a phenyl group. Moreover, n represents the integer of 1-100. Compounds represented by), the general formula _{(IV) CH 2 = CH-} CO-R 7 (IV) ( wherein, R ₇ represents a lower alkyl group of C ₁ -C _4.)
In the compound represented by the general formula _{(V) CH 2 = CH-} CO-N (R 8) R 8 '(V) ( wherein, R ₈ and R _8' lower alkyl group is hydrogen or C ₁ -C ₄ represents that there is no R ₈ and R ₈ 'are hydrogen at the same time. the compound represented by), the general formula _{(VI) CH 2 = CH-} O-R 9 (VI) ( wherein, R ₉ is C ₁ ~C represent a ₄ lower alkyl group.)
The water-soluble thermoplastic film according to claim 1, which is one or more compounds selected from the compounds represented by: 6. A water-soluble packaging material comprising the water-soluble thermoplastic film according to claim 1. 7. A seed tape substrate comprising the water-soluble thermoplastic film according to claim 1. 8. A substrate for printing, comprising the water-soluble thermoplastic film according to claim 1.