KR101577911B1 - A method for preparing polyvinyl alcohol films by the heterogeneous surface saponification of polyvinyl acetate films - Google Patents

Abstract

The present invention relates to a method for manufacturing a polyvinyl alcohol film having the enlarged specific surface area by having a pleated shape. The present invention relates to a method for manufacturing a polyvinyl alcohol film having the pleated surface, comprising the step of saponifying a polyacetic acid vinyl film, while the polyacetic acid vinyl film is soaked in a first solvent maintaining a film shape of the polyacetic acid vinyl film to converting into the polyvinyl alcohol film.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method for producing a polyvinyl alcohol film by heterogeneous saponification of polyvinyl alcohol films,

The present invention relates to a method for producing a polyvinyl alcohol film having a specific surface area improved by having a corrugated form on a surface thereof, and a method of producing a polyvinyl alcohol film by impregnating a polyvinyl acetate film with a first solvent capable of maintaining a film form, And converting the polyvinyl alcohol film to a polyvinyl alcohol film by saponifying the polyvinyl alcohol film.

A method of producing a film with an organic polymer includes a solution casting method in which a high viscosity polymer solution obtained by dissolving a polymer in a solvent is developed on a wide and smooth surface free from adherence to volatilize the solvent and obtain a film, A melt processing method in which a polymer material is heated to a melting temperature or a softening temperature or higher and applied to obtain a film. The melt processing method is disadvantageous in that it is not suitable for a high-quality film such as an optically functional film because the film thickness is not adjusted very precisely and fine lines (so-called dy line) are formed on the film. On the other hand, the solution casting method has a better optical isotropy and thickness uniformity than the melt processing method, and can produce a film having a small foreign substance. In addition, since the method of use and installation equipments are experimentally simple, inorganic materials for various polymer materials It is possible to easily produce a film exhibiting excellent characteristics depending on the content.

On the other hand, the saponified polyvinyl alcohol has a relatively low viscosity as compared with other polymers, is nontoxic, and has unique properties such as biodegradability. In addition, it has excellent miscibility when blended with other polymers and is used for various purposes such as medical materials, packaging materials, release films, and water-soluble films. However, the production methods of the polyvinyl alcohol films reported so far have not been related to changing the surface of the polyvinyl alcohol film, and in particular, there has been no report on a method of controlling the surface roughness of the polyvinyl alcohol film.

In order to maximize the specific surface area of the polyvinyl alcohol film, the inventors of the present invention have made efforts to control the formation or roughness of nano wrinkles on the surface of each film and apply them to various applications. As a result, It has been confirmed that when a polyvinyl acetate film is prepared by a solution casting method and then converted to polyvinyl alcohol through a nonuniform saponification process, wrinkles are formed on the surface to improve the specific surface area, thereby completing the present invention .

An object of the present invention is to provide a polyvinyl alcohol film having wrinkles formed on its surface and a method for producing the same.

In order to achieve the above object, the present invention provides a method for producing a polyvinyl alcohol film, comprising the steps of saponifying a polyvinyl acetate film into a polyvinyl alcohol film while the polyvinyl acetate film is impregnated with a first solvent capable of maintaining a film form, The present invention provides a method for producing a polyvinyl alcohol film on which wrinkles are formed.

The method of producing a polyvinyl alcohol film according to the present invention can produce a polyvinyl alcohol film having a new structure having a specific surface area as compared with a conventional polyvinyl alcohol film having a smooth surface by having a corrugated form on the surface thereof, The film can be applied to grafts, synthetic fibers, packaging materials, coating agents, adhesives, polarizing films and the like to achieve more improved effects.

In the present invention, polyvinyl acetate can be prepared by bulk polymerization, solution polymerization, emulsion polymerization and suspension polymerization. In particular, bulk polymerization is advantageous in that relatively high molecular weight poly (vinyl acetate) can be obtained because the probability of chain transfer is lower than other polymerization methods because monomers are present only in the polymerization system.

In the present invention, the polyvinyl acetate film can be produced by molding a polymer solution in which polyvinyl acetate is dissolved in a solvent, followed by drying. Specifically, by a solution casting method (solvent casting method) in which a high-viscosity polymer solution obtained by dissolving polyvinyl acetate in a solvent is developed on a large smooth surface free from adhesion and then the solvent is volatilized to produce a film .

The solvent for dissolving the polyvinyl acetate in the present invention is not particularly limited as long as it is a solvent capable of dissolving polyvinyl acetate, and preferably methanol, ethanol, tetrahydrofuran (THF), dimethylsulfoxide (DMSO) These mixtures can be used as a solvent.

The concentration of polyvinyl acetate in the polymer solution may be 4 wt.% To 20 wt.%, And more preferably 6 wt.% To 10 wt.%. When the concentration is less than 4 wt.%, The solution is too thin to form a film, and when it is more than 20 wt.%, It is difficult to form a film due to high viscosity.

At this time, it may be dissolved in a hot water bath at a temperature of 30 ° C to 50 ° C for 0.1 hour to 5 hours while stirring. Preferably at a temperature of < RTI ID = 0.0 > 40 C. < / RTI > If it is used out of the range of the above temperature, the polyvinyl acetate may not be completely dissolved and a uniform film may not be formed.

Also, in order to stabilize the polymer solution, the preparation method according to the present invention may be carried out by allowing the solution to stand at room temperature of 20 ° C to 35 ° C for 0.5 hours to 5 hours. Preferably at a temperature of < RTI ID = 0.0 > 20 C. < / RTI >

Thereafter, the polymer solution is developed on the surface of a smooth substrate having no adhesiveness, and then the solvent is volatilized to produce a film. A vacuum dryer can be used to volatilize the solvent, and a polyvinyl acetate film placed on a flat surface can be obtained by volatilizing the solvent for 24 to 60 hours at a temperature of about 30 ° C to 50 ° C.

A polyvinyl alcohol film having wrinkles formed on its surface can be prepared by converting the polyvinyl acetate film into a polyvinyl alcohol film by saponification in a state in which the polyvinyl acetate film is immersed in a solvent capable of maintaining the film form have.

The production method of the present invention is not saponification in a state where vinyl acetate is dissolved in a solvent but polyvinyl acetate film is produced and then saponified while maintaining the film form. Surprisingly, a polyalcohol vinyl film having wrinkles formed on the surface of the film . Therefore, it is important to use a solvent that can maintain the polyvinyl acetate film shape when saponifying.

Specifically, the polyvinyl acetate film is impregnated with an acid solution or an alkaline solution containing a dispersant, a swelling agent, and water to convert the -OCOCH ₃ group of the polyvinyl acetate film into a -OH group by nonuniform saponification to form a polyvinyl alcohol film Can be prepared.

The acid in the acid solution for saponification may be hydrochloric acid, nitric acid, or a mixture thereof, and the alkali in the alkali solution for saponification may be sodium chloride, sodium hydroxide, potassium hydroxide, or a mixture thereof, but is not limited thereto.

The dispersing agent may be sodium sulfate, sodium sulfite, calcium sulfate, magnesium sulfate or a mixture thereof.

The swelling agent may be methanol, ethanol, propanol, ethylene glycol, propylene glycol, tetrahydrofuran (THF), dimethylsulfoxide (DMSO), benzene, acetone or a mixture thereof. Preferably, methanol can be used which is easy to obtain, low in cost, low in boiling point, and easy to handle.

The acid solution may be hydrochloric acid, nitric acid or a mixture thereof; A dispersing agent selected from sodium sulfate, sodium sulfite, calcium sulfate, magnesium sulfate or a mixture thereof; Any one of swelling agents selected from methanol, ethanol, propanol, ethylene glycol, propylene glycol, tetrahydrofuran (THF), dimethylsulfoxide (DMSO), benzene, acetone or mixtures thereof; And water, preferably distilled water, but the present invention is not limited thereto.

The alkali solution may be sodium chloride, sodium hydroxide, potassium hydroxide, or a mixture thereof; A dispersing agent selected from sodium sulfate, sodium sulfite, calcium sulfate, magnesium sulfate or a mixture thereof; Any one of swelling agents selected from methanol, ethanol, propanol, ethylene glycol, propylene glycol, tetrahydrofuran (THF), dimethylsulfoxide (DMSO), benzene, acetone or mixtures thereof; And water, preferably distilled water, but the present invention is not limited thereto.

More specifically, the alkali solution comprises sodium chloride; Sodium sulfate; Methanol; And water, preferably distilled water, to dissolve and dissolve, but is not limited thereto.

In the present invention, the saponification of the polyvinyl acetate film can be carried out at a temperature of from 10 캜 to 70 캜 for 10 hours to 300 hours. Preferably 40 to < RTI ID = 0.0 > 50 C < / RTI > for 30 to 150 hours. The saponification is performed at a temperature ranging from 10 ° C to 70 ° C in order to maximize the activation of the swelling agent serving as a catalyst.

The degree of saponification of the present invention is preferably 60% to 99.9%. Here, the "degree of saponification" represents the ratio of units actually saponified to vinyl alcohol units among the units obtained by conversion to vinyl alcohol units by saponification, and can be measured by the method described in JIS. Specifically, it can be expressed as a ratio of the number of moles of the compound converted to the -OH group to the number of moles of the compound having the entire -OCOCH ₃ group.

In another aspect, the present invention provides a polyvinyl alcohol film having wrinkles formed on a film surface.

The depth of the corrugation of the polyvinyl alcohol film may be 10 nm to 1 탆.

A polyvinyl alcohol film having wrinkles formed on the film surface of the present invention can be produced by the production method according to the present invention. Conventional polyvinyl alcohol films are prepared to have a smooth surface, whereas polyvinyl alcohol films produced through the heterogeneous saponification reaction according to the present invention have uneven wrinkles on the surface of the film, So that the specific surface area of the film can be maximized (Figs. 1 and 2).

As described above, the novel type polyvinyl alcohol film formed with wrinkles on the film has improved specific surface area and can be used in various fields such as grafts, synthetic fibers, packaging materials, coating agents, adhesives, and polarizing films, have.

According to the production process of the present invention, a new polyvinyl alcohol film having wrinkles formed on the surface thereof and having an improved specific surface area can be produced as compared with the conventional polyvinyl alcohol film.

1 is a confocal scanning microscope photograph of a heterogeneous saponified polyvinyl alcohol film produced according to the amount of alkali solution. The temperature is the same at a temperature of 50 DEG C and a saponification time of 120 hours.
(a) NaOH (5g), Na 2 SO 4 (5g), MeOH (5g)
(b) NaOH (10 g), Na ₂ SO ₄ (10 g), MeOH (10 g)
2 is a confocal scanning microscope photograph of a heterogeneous saponified polyvinyl alcohol film produced according to the saponification time. The alkali solution required for saponification is the same as NaOH (10 g), Na ₂ SO ₄ (10 g), MeOH (10 g), temperature 50 ° C.
(a) Saponification time 90 hours
(b) Saponification time 150 hours

Hereinafter, preferred embodiments of the present invention will be described in order to facilitate understanding of the present invention. However, the following examples are provided to further understand the present invention, and the present invention is not limited by the examples. Aldrich reagent was used as the starting material and reaction reagent in the compounds used below. All solvents were pure and used without drying or purification.

In the following Production Examples 1 to 4, experiments were conducted to produce polyvinyl acetate films. Polyvinyl acetate nano nonwoven fabric having the optimum conditions was prepared by controlling a polyvinyl acetate solution dissolved in methanol.

Production Example 1: Production of poly (vinyl acetate) film by solution casting method

The polyvinyl acetate solution (4 wt.%) (1.58 g) was added to a 99% methanol solvent (37.92 ml) and stirred at 40 ° C for 30 minutes. The resulting polyvinyl acetate solution was dried at room temperature for about one hour, cm x 10 cm stainless steel box. The solvent was removed in a 40 < 0 > C vacuum dryer for 48 hours. However, polyvinyl acetate film was not formed.

Production Example 2: Production of poly (vinyl acetate) film by solution casting method

6 wt.% Of polyvinyl acetate (2.37 g) was added to a 99% methanol solvent (37.13 ml), stirred at 40 ° C for 30 minutes, and then the resulting polyvinyl acetate solution was dried at room temperature for about one hour. The remaining experimental conditions were the same as in Production Example 1. A polyvinyl acetate film was not formed similarly to the above-mentioned Production Example 1.

Production Example 3: Production of polyvinyl acetate film by solution casting method

8 wt.% Of polyvinyl acetate (3.16 g) was added to a purity 99% methanol solvent (36.34 ml) and stirred at 40 ° C for 30 minutes. The resulting polyvinyl acetate solution was dried at room temperature for about one hour, cm x 10 cm stainless steel box. The solvent was removed in a 40 ° C vacuum dryer for 48 hours to form a polyvinyl acetate film.

Production Example 4: Production of poly (vinyl acetate) film by solution casting method

10 wt.% Of polyvinyl acetate (3.95 g) was added to a 99% methanol solvent (35.55 ml), stirred at 40 ° C for 30 minutes, and the resulting polyvinyl acetate solution was dried at room temperature for about one hour. The remaining experimental conditions were the same as in Production Example 3, in which a polyvinyl acetate film was formed.

division The polymer used Polymer concentration Temperature Vapor pressure dry
time film
produce Production Example 1 Polyvinyl acetate
(PVAc) 4 wt.% 40 ℃ 35cmHg 48 hours x Production Example 2 Polyvinyl acetate
(PVAc) 6 wt.% ≪ 40 ℃ 35cmHg 48 hours x Production Example 3 Polyvinyl acetate
(PVAc) 8 wt.% ≪ 40 ℃ 35cmHg 48 hours o Production Example 4 Polyvinyl acetate
(PVAc) 10 wt.% ≪ 40 ℃ 35cmHg 48 hours o

In the following Examples 1 to 15, the polyvinyl alcohol film was produced by saponifying the polyvinyl acetate film prepared in Production Example 3. The polyvinyl acetate film prepared in Production Example 3 was saponified using an alkali solution, and the film was put in distilled water, stirred again, and then dried at room temperature to prepare a polyvinyl alcohol film.

Example 1: Production of polyvinyl alcohol film by non-uniform saponification of polyvinyl acetate film

(100 g), NaOH (10 g), Na ₂ SO ₄ (10 g) and MeOH (10 g) were gently stirred for saponification of polyvinyl acetate films prepared by solution casting. Polyvinyl acetate film (1 g) was added to the prepared alkali solution, and saponification reaction was carried out at 50 ° C for 30 hours. After the saponification reaction, the film was washed several times with distilled water, and the washed film was dried at room temperature for 12 hours to prepare a saponified polyvinyl alcohol film.

In the following Examples 2 to 15, polyvinyl alcohol films were prepared by varying the saponification conditions according to Table 2.

Example 2: Production of polyvinyl alcohol film by non-uniform saponification of polyvinyl acetate film

A saponified polyvinyl alcohol film was prepared in the same manner as in Example 1, except that the polyvinyl acetate film was added to the prepared alkali solution and the saponification reaction was carried out at 50 ° C for 60 hours.

Example 3: Production of polyvinyl alcohol film by non-uniform saponification of polyvinyl acetate film

A saponified polyvinyl alcohol film was prepared in the same manner as in Example 1, except that the polyvinyl acetate film was added to the prepared alkali solution and the saponification reaction was carried out at 50 占 폚 for 90 hours.

Example 4: Production of polyvinyl alcohol film by non-uniform saponification of polyvinyl acetate film

A saponified polyvinyl alcohol film was prepared in the same manner as in Example 1, except that the polyvinyl acetate film was added to the prepared alkali solution and the saponification reaction was carried out at 50 占 폚 for 120 hours.

Example 5: Production of polyvinyl alcohol film by non-uniform saponification of polyvinyl acetate film

A saponified polyvinyl alcohol film was prepared in the same manner as in Example 1, except that the polyvinyl acetate film was added to the prepared alkali solution and the saponification reaction was carried out at 50 ° C for 150 hours.

Example 6: Preparation of polyvinyl alcohol film by non-uniform saponification of polyvinyl acetate film

The same procedure as in Example 1 was carried out except that an alkali solution prepared from distilled water (50 mL), NaOH (5 g), Na ₂ SO ₄ (5 g) and MeOH Alcohol film was prepared.

Example 7: Production of polyvinyl alcohol film by non-uniform saponification of polyvinyl acetate film

A saponified polyvinyl alcohol film was prepared in the same manner as in Example 6, except that the polyvinyl acetate film was added to the prepared alkali solution and the saponification reaction was carried out at 50 ° C for 60 hours.

Example 8: Preparation of polyvinyl alcohol film by non-uniform saponification of polyvinyl acetate film

A saponified polyvinyl alcohol film was prepared in the same manner as in Example 6, except that the polyvinyl acetate film was added to the prepared alkali solution and the saponification reaction was carried out at 50 占 폚 for 90 hours.

Example 9: Preparation of polyvinyl alcohol film by non-uniform saponification of polyvinyl acetate film

A saponified polyvinyl alcohol film was prepared in the same manner as in Example 6, except that the polyvinyl acetate film was added to the prepared alkali solution and the saponification reaction was carried out at 50 ° C for 120 hours.

Example 10: Production of polyvinyl alcohol film by non-uniform saponification of polyvinyl acetate film

A saponified polyvinyl alcohol film was prepared in the same manner as in Example 6, except that the polyvinyl acetate film was added to the prepared alkali solution and the saponification reaction was carried out at 50 ° C for 150 hours.

Example 11: Preparation of polyvinyl alcohol film by non-uniform saponification of polyvinyl acetate film

A saponified polyvinyl alcohol film was produced in the same manner as in Example 1, except that the polyvinyl acetate film was added to the prepared alkali solution and the saponification reaction was carried out at 40 占 폚 for 30 hours.

Example 12: Preparation of polyvinyl alcohol film by non-uniform saponification of polyvinyl acetate film

A saponified polyvinyl alcohol film was produced in the same manner as in Example 1, except that the polyvinyl acetate film was added to the prepared alkali solution and the saponification reaction was carried out at 40 ° C for 60 hours.

Example 13: Preparation of polyvinyl alcohol film by non-uniform saponification of polyvinyl acetate film

A saponified polyvinyl alcohol film was prepared in the same manner as in Example 1 except that polyvinyl acetate film was added to the prepared alkali solution and the saponification reaction was carried out at 40 占 폚 for 90 hours.

Example 14: Preparation of polyvinyl alcohol film by non-uniform saponification of polyvinyl acetate film

A saponified polyvinyl alcohol film was prepared in the same manner as in Example 1, except that the polyvinyl acetate film was added to the prepared alkali solution and the saponification reaction was carried out at 40 ° C for 120 hours.

Example 15: Preparation of polyvinyl alcohol film by non-uniform saponification of polyvinyl acetate film

A saponified polyvinyl alcohol film was produced in the same manner as in Example 1, except that the polyvinyl acetate film was added to the prepared alkali solution and the saponification reaction was carried out at 40 占 폚 for 150 hours.

The experimental conditions and the results of the above-described Examples 1 to 15 are summarized in Table 2 below.

division
Distilled water
Alkali solution Temperature Saponification
Reaction time NaOH Na ₂ SO ₄ MeOH Example 1 100 mL 10 g 10 g 10 g 50 30 hours Example 2 100 mL 10 g 10 g 10 g 50 60 hours Example 3 100 mL 10 g 10 g 10 g 50 90 hours Example 4 100 mL 10 g 10 g 10 g 50 120 hours Example 5 100 mL 10 g 10 g 10 g 50 150 hours Example 6 50 mL 5 g 5 g 5 g 50 30 hours Example 7 50 mL 5 g 5 g 5 g 50 60 hours Example 8 50 mL 5 g 5 g 5 g 50 90 hours Example 9 50 mL 5 g 5 g 5 g 50 120 hours Example 10 50 mL 5 g 5 g 5 g 50 150 hours Example 11 100 mL 10 g 10 g 10 g 40 30 hours Example 12 100 mL 10 g 10 g 10 g 40 60 hours Example 13 100 mL 10 g 10 g 10 g 40 90 hours Example 14 100 mL 10 g 10 g 10 g 40 120 hours Example 15 100 mL 10 g 10 g 10 g 40 150 hours

Claims (13)

A method for producing a polyvinyl alcohol film, comprising the steps of: saponifying a polyvinyl acetate film with a polyvinyl acetate film impregnated with a first solvent capable of maintaining a film form, and converting the polyvinyl acetate film into a polyvinyl alcohol film; Gt;
The method for producing a polyvinyl alcohol film according to claim 1, wherein the polyvinyl acetate film is produced by molding a solution of a polymer in which polyvinyl acetate is dissolved in a second solvent, followed by drying.
The method for producing a polyvinyl alcohol film according to claim 2, wherein the concentration of polyvinyl acetate in the polymer solution is from 6 wt.% To 20 wt.%.
The method for producing a polyvinyl alcohol film according to claim 1, wherein the polyvinyl acetate film is impregnated with an alkaline solution containing a dispersant and a swelling agent to perform nonuniform saponification.
The method for producing a polyvinyl alcohol film according to claim 4, wherein the dispersant is sodium sulfate, sodium sulfite, calcium sulfate, magnesium sulfate or a mixture thereof.
5. The composition of claim 4, wherein the swelling agent is selected from the group consisting of poly (methyl methacrylate), ethylene glycol, propylene glycol, tetrahydrofuran (THF), dimethylsulfoxide (DMSO), benzene, acetone, A method for producing a vinyl alcohol film.
5. The method of claim 4, wherein the alkali solution comprises sodium chloride, sodium hydroxide, potassium hydroxide, or a mixture thereof; Any one of dispersants selected from sodium sulfate, sodium sulfite, calcium sulfate, magnesium sulfate, and mixtures thereof; Any one of swelling agents selected from methanol, ethanol, propanol, ethylene glycol, propylene glycol, tetrahydrofuran (THF), dimethylsulfoxide (DMSO), benzene, acetone or mixtures thereof; And distilled water. The method for producing a polyvinyl alcohol film according to claim 1,
The method for producing a polyvinyl alcohol film according to claim 1, wherein the saponifying step is carried out at a temperature ranging from 30 ° C to 60 ° C for 10 hours to 200 hours.
The method of claim 1, wherein the first solvent is selected from the group consisting of sodium chloride, sodium hydroxide, potassium hydroxide, or mixtures thereof; A dispersing agent selected from sodium sulfate, sodium sulfite, calcium sulfate, magnesium sulfate or a mixture thereof; Any one of swelling agents selected from methanol, ethanol, propanol, ethylene glycol, propylene glycol, tetrahydrofuran (THF), dimethylsulfoxide (DMSO), benzene, acetone or mixtures thereof; And distilled water are mixed and dissolved. The method for producing a polyvinyl alcohol film according to claim 1,
The method of claim 1, wherein the first solvent is selected from the group consisting of sodium chloride; Sodium sulfate; Methanol; And distilled water are mixed and dissolved. The method for producing a polyvinyl alcohol film according to claim 1,
3. The method of producing a polyvinyl alcohol film according to claim 2, wherein the second solvent is methanol.
A polyvinyl alcohol film produced by the production method of any one of claims 1 to 11 and having wrinkles on its surface.
The polyvinyl alcohol film according to claim 12, wherein the depth of the corrugation of the polyvinyl alcohol film is 10 nm to 1 탆.

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