KR100665090B1 - Method for Preparing Polyvinylalcohol Film from Waste Polyvinylalcohol and product therefrom - Google Patents

Abstract

The method for producing a polyvinyl alcohol film of the present invention comprises polyvinyl alcohol having molecular variables of number average polymerization degree 1,000 to 2,000, alternating diad group content of 50 to 55% and saponification degree of 80.0 to 99.9% obtained from waste polyvinyl alcohol. Dissolved in water at a concentration of 0.1-20 g / dl; Forming a film by forming the dissolved polyvinyl alcohol; And stretching the prepared film at 10 to 60 ℃.

Polyvinyl alcohol, film, film formation, wet stretching, dry stretching

Description

Method for preparing polyvinyl alcohol film using waste polyvinyl alcohol and film therefor {Method for Preparing Polyvinylalcohol Film from Waste Polyvinylalcohol and product therefrom}

Field of invention

The present invention relates to a method for producing a polyvinyl alcohol film using waste polyvinyl alcohol. More specifically, the present invention provides a method for producing a film having functionalities such as strength, elastic modulus, transparency, and the like, which can be used in place of the existing hybrid array polyvinyl alcohol by recycling the hybrid array polyvinyl alcohols by waste polyvinyl alcohol. It relates to a film produced by.

Background of the Invention

Polyvinyl alcohol was tested for saponification of poly (vinyl acetate) by Herrmann and Haehnel of Germany in 1924 [WOHerrmann and W. Hachnel, German Patent, 450, 286 (1924)]. Found first. In addition to polyvinyl acetate, polyvinyl alcohol is a polymer made by saponifying various types of polyvinyl esters and polyvinyl ethers-based polymers. It has both environmentally friendly properties such as properties, water solubility and biocompatibility.

In particular, polyvinyl alcohol has various characteristics ranging from water solubility to water resistance depending on molecular weight, stereoregularity, and degree of saponification. Therefore, polyvinyl alcohol may be used for coatings, clothing fibers, industrial fibers, food packaging films, liquid and gas separation membranes, polarizing films, It can be widely used in the manufacture of medical polymers, etc., and it can be said to be a very useful polymer having unlimited industrial applications.

As such, polyvinyl alcohol can be used in various applications, but since its own cost is very expensive, a method of recovering and recycling waste polyvinyl alcohol is actively studied.

In particular, since polyvinyl alcohol is a hardly decomposable material, by recovering and recycling it, not only environmental conservation, but also cost reduction and energy saving due to resource recycling can be brought, and waste polyvinyl alcohol can be promoted as an eco-friendly industry of related companies. It is absolutely necessary to recycle it.

In general, a polyvinyl alcohol resin having a uniform degree of saponification is used for the water-soluble film. The preparation of the solution using a polyvinyl alcohol resin, a plasticizer, a surfactant, and the like is the same as the production of other polyvinyl alcohol films, but the saponification degree of the polyvinyl alcohol resin used at this time is suitably 82 to 92%. It is known that water solubility is inadequate in saponification degree of 80% or less and 95% or more. In the case of a water-soluble polyvinyl alcohol film using a low saponification polyvinyl alcohol resin, an inorganic filler such as silicone or talc is added to reinforce toughness and impact resistance. In addition, it is also necessary to shorten the swelling time of the film by giving unevenness to the surface of the film so that it can be quickly dissolved in water under the desired conditions.

Polarizing film plays the most important role among LCD parts. Polyvinyl alcohol films, which are used exclusively for polarizing films, have excellent optical properties, and thus, have excellent transparency and high birefringence when stretched. The polyvinyl alcohol film used as an optical film requires transparency, stretchability, and thickness uniformity in particular. Therefore, the content of 1,2-diol of the polyvinyl alcohol resin is 1.5 mol% or less, saponification degree is 99% or more, and the film thickness is preferably 40 to 120 μm, and the thickness of the film generally used is 75 μm.

The stretchability of polymers is generally described in molecular weight [C.W.M.Bastiaansen, J.Polym. Sci., Polym. Phys. Ed., 28, 1475 (1990)]. Molecular weight distribution [C.W.M.Bastiannsen, J.Polym, Sci., Polym. Phys. Ed., 28, 1475 (1990)], crystallinity of unstretched films [C.Sawatari, Y.Yamamoto, N.Yanagida, and M.Matsuo, Polymer, 34, 956 (1993)], and Concentration of polymer solution [T. Kanamoto, A. Tsurata, K. Tanaka, and RS Porter. Polym, J., 15, 327 (1983)]. In general, as the molecular weight increases, the draw ratio increases. When the molecular weight is large enough, the draw ratio mainly depends on the film concentration.

The inventor of the present invention has developed a method for producing a polyvinyl alcohol film having excellent physical properties by band stretching polyvinyl alcohol having a high alternating ultra high molecular weight (Korean Patent No. 179940).

However, the precursors for obtaining polyvinyl alcohol so far known are very expensive as the price of vinyl acetate which is a polymerization monomer of polyvinyl acetate used as a precursor of hybrid array polyvinyl alcohol, and thus a polyvinyl alcohol film produced therefrom. Will also rise in price.

In order to solve the above problems, the present inventors can produce a film using polyvinyl alcohol having a specific range of molecular parameters obtained from waste polyvinyl alcohol, thereby securing physical properties of the existing polyvinyl alcohol film. The company is beginning to develop a method for producing polyvinyl alcohol films at a fairly low cost.

An object of the present invention is to provide a method for producing a polyvinyl alcohol film capable of cost reduction by recycling resources by using waste polyvinyl alcohol.

Another object of the present invention is to provide a method for producing a polyvinyl alcohol film having excellent strength, modulus of elasticity, transparency, and the like to replace the existing hybrid array polyvinyl alcohol.

Another object of the present invention is to provide a method for producing a polyvinyl alcohol film excellent in environmental protection by recovering and recycling polyvinyl alcohol which is a hardly decomposable material.

The above and other objects of the present invention can be achieved by the present invention described in detail below.

Summary of the Invention

The method for producing a polyvinyl alcohol film of the present invention comprises polyvinyl alcohol having molecular variables of number average polymerization degree 1,000 to 2,000, alternating diad group content of 50 to 55% and saponification degree of 80.0 to 99.9% obtained from waste polyvinyl alcohol. Dissolved in water at a concentration of 0.1-20 g / dl; Forming a film by forming the dissolved polyvinyl alcohol; And it consists of a step of stretching the prepared film at 10 ~ 60 ℃. Hereinafter, each step of the present invention will be described in detail below.

Detailed Description of the Invention

According to the present invention, a method for producing polyvinyl alcohol according to the present invention includes low molecular weight polyvinyl alcohol having a molecular variable of number average polymerization degree of 1,000 to 2,000, alternating diad group content of 50 to 55%, and saponification degree of 80.0 to 99.9%. After dissolving in water at a concentration of 0.1 to 20 g / dl, the film prepared by forming the film is wet or dry drawn at 10 to 60 ° C.

Unlike the conventional method, the polyvinyl alcohol film production method of the present invention is characterized by using waste polyvinyl alcohol as a raw material. The precursors for producing polyvinyl alcohol so far known are very expensive, and the price of the polyvinyl alcohol film produced therefrom is inevitably rising. Therefore, in the present invention, by using the polyvinyl alcohol having a specific range of molecular parameters obtained from the waste polyvinyl alcohol as a raw material, it is possible to significantly reduce the cost compared to the conventional manufacturing method.

Molecular parameters of polyvinyl alcohol suitable for use as a raw material in the present invention are that the number average degree of polymerization is 1,000 to 2,000, the content of alternating diad groups is 50 to 55%, and the degree of saponification is 80.0 to 99.9%. Suitable.

When using polyvinyl alcohol outside the above conditions as a raw material, it is not possible to secure physical properties that can replace the existing polyvinyl alcohol film.

The low molecular weight polyvinyl alcohol having molecular variables of the number average degree of polymerization of 1,000 to 2,000, the alternating diad group content of 50 to 55%, and the degree of saponification of 80.0 to 99.9% is dissolved in water and then formed into a film to prepare a film. .

In the present invention, the optimum film concentration is preferably 0.1-20 g / dl.

In general, in order to manufacture a polyvinyl alcohol film with an optimal draw ratio, it may be said that consideration of its optimal film forming concentration is necessary, but conventional methods do not consider this. This is because the viscosity measurement method, which is generally used to calculate the optimum entanglement concentration of the chain, was difficult to apply due to the heterogeneity of the polyvinyl alcohol solution. In the present invention, in order to effectively consider such a film formation concentration, the polyvinyl alcohol deposited by each concentration by wet stretching to inversely estimate the concentration showing the maximum draw ratio, it is possible to have physical properties and orientation from the sample used in the present invention The film forming conditions of the film were established.

If the film formation concentration is out of the above range, it is not possible to secure the desired physical properties.

The polyvinyl alcohol dissolved in the water is formed into a film by a conventional method, the polyvinyl alcohol film formed is subjected to a stretching process.

In general, the thermal stretching method known as the method of stretching the membrane could not effectively increase the draw ratio in the case of polyvinyl alcohol, and has side effects such as yellowing and refolding accompanied with thermal decomposition of the membrane.

In the present invention, the stretching method is wet or dry stretching.

The wet stretching is performed by stretching the film-formed polyvinyl alcohol film about 3 to 5 times in a boric acid solution (2 to 4% by weight) at a stretching temperature of 10 to 60 ° C., and then drying the stretched film at 30 ° C. for 24 to 48 hours. Let's do it.

The dry stretching is carried out by dry strip stretching of the polyvinyl alcohol film formed by a conventional method, at a stretching temperature of 10 to 60 ℃.

The invention can be better understood by the following examples, which are intended for the purpose of illustration of the invention and are not intended to limit the scope of protection defined by the appended claims.

Example

Example 1

Polyvinyl alcohol having a number average degree of polymerization of 1700, alternating sequencer content of 53.9%, and saponification degree of 99.0% of waste polyvinyl alcohol was mixed in a beaker at a concentration of 2.5 g / dl using water as a solvent and at 100 ° C. After dissolving completely for 2 hours to prepare a solution, it was poured into a stainless steel dish and dried under vacuum for 48 hours to obtain a polyvinyl alcohol film having a thickness of 70 μm, transmittance of 85%, tensile strength of 0.08 GPa, and tensile modulus of 3 GPa.

The polyvinyl alcohol film prepared above was fixed at a stretching temperature of 30 ° C. and stretched four times at a rate of 10 mm / min in a boric acid solution (2 to 4%) to have a thickness of 10 μm, a transmittance of 77%, a tensile strength of 0.5 GPa, and a tensile strength. A polyvinyl alcohol film having an elastic modulus of 11 GPa was obtained.

Example 2

Polyvinyl alcohol having a number average degree of polymerization of 1500, an alternating content of 54.0%, and a saponification degree of 99.0% of waste polyvinyl alcohol was mixed in a beaker at a concentration of 2.5 g / dl, using water as a solvent, at 100 ° C. After completely dissolving for 2 hours to prepare a solution, it was poured into a stainless steel dish and dried under vacuum for 48 hours to obtain a polyvinyl alcohol film having a thickness of 70 μm, a transmittance of 90%, a tensile strength of 0.07 GPa, and a tensile modulus of 2.5 GPa.

The polyvinyl alcohol film prepared above was fixed at a stretching temperature of 30 ° C. and stretched four times at a rate of 10 mm / min in a boric acid solution (2 to 4%) to have a thickness of 10 μm, a transmittance of 83%, a tensile strength of 0.4 GPa, and a tensile strength. A polyvinyl alcohol film having an elastic modulus of 9 GPa was obtained.

Example 3

Polyvinyl alcohol having a number average degree of polymerization of 1700, alternating content of 53.9.0%, and saponification degree of 99.0% of waste polyvinyl alcohol was mixed in a beaker at a concentration of 0.1 g / dl using water as a solvent and 100 After dissolving completely at 2 ° C. for 2 hours to prepare a solution, it was poured into a stainless steel dish and dried under vacuum for 48 hours to obtain a polyvinyl alcohol film having a thickness of 40 μm, a transmittance of 88%, a tensile strength of 0.02 GPa, and a tensile modulus of 1.5 GPa.

The polyvinyl alcohol film prepared above was fixed at a stretching temperature of 30 ° C. and stretched four times at a rate of 10 mm / min in a boric acid solution (2 to 4%) to have a thickness of 5 μm, a transmittance of 84%, a tensile strength of 0.1 GPa, and a tensile strength. A polyvinyl alcohol film having an elastic modulus of 3 GPa was obtained.

Example 4

A polyvinyl alcohol having a number average degree of polymerization of 1500, an alternating content of 54.0%, and a saponification degree of 99.0% of waste polyvinyl alcohol was mixed with a beaker at a concentration of 0.1 g / dl using water as a solvent and at 100 ° C. After dissolving completely for 2 hours to prepare a solution, it was poured into a stainless steel dish and dried under vacuum for 48 hours to obtain a polyvinyl alcohol film having a thickness of 40 μm, a transmittance of 94%, a tensile strength of 0.01 GPa, and a tensile modulus of 1 GPa.

The polyvinyl alcohol film prepared above was fixed at a stretching temperature of 30 ° C. and stretched four times at a rate of 10 mm / min in a boric acid solution (2 to 4%) to have a thickness of 5 μm, a permeability of 88%, a tensile strength of 0.06 GPa, and a tensile strength. A polyvinyl alcohol film having an elastic modulus of 2.5 GPa was obtained.

Example 5

Polyvinyl alcohol having a number average degree of polymerization of 1700, alternating content of 53.9%, and saponification degree of 99.0% of waste polyvinyl alcohol was mixed in a beaker at a concentration of 1.0 g / dl using water as a solvent. After completely dissolving for 2 hours to prepare a solution, it was poured into a stainless steel dish and dried under vacuum for 48 hours to obtain a polyvinyl alcohol film having a thickness of 60 μm, transmittance of 87%, tensile strength of 0.05 GPa, and tensile modulus of 2.4 GPa.

The polyvinyl alcohol film prepared above was fixed at a stretching temperature of 30 ° C. and stretched four times at a rate of 10 mm / min in a boric acid solution (2 to 4%) to have a thickness of 8 μm, a transmittance of 80%, a tensile strength of 0.2 GPa, and a tensile strength. A polyvinyl alcohol film having an elastic modulus of 6.5 GPa was obtained.

Example 6

Polyvinyl alcohol having a number average degree of polymerization of 1500, an alternating content of 54.0%, and a saponification degree of 99.0% of waste polyvinyl alcohol was mixed in a beaker at a concentration of 1.0 g / dl using water as a solvent and at 100 ° C. After completely dissolving for 2 hours to prepare a solution, it was poured into a stainless steel dish and dried under vacuum for 48 hours to obtain a polyvinyl alcohol film having a thickness of 60 μm, a transmittance of 91%, a tensile strength of 0.03 GPa, and a tensile modulus of 2 GPa.

The polyvinyl alcohol film prepared above was fixed at a stretching temperature of 30 ° C. and stretched four times at a rate of 10 mm / min in a boric acid solution (2 to 4%) to have a thickness of 8 μm, a transmittance of 86%, a tensile strength of 0.15 GPa, and a tensile strength. A polyvinyl alcohol film having an elastic modulus of 5 GPa was obtained.

Example 7

Polyvinyl alcohol having a number average degree of polymerization of 1700, alternating sequencer content of 53.9%, and saponification degree of 99.0% of waste polyvinyl alcohol was mixed in a beaker at a concentration of 5.0 g / dl using water as a solvent and at 100 ° C. After completely dissolving for 2 hours to prepare a solution, it was poured into a stainless steel dish and dried under vacuum for 48 hours to obtain a polyvinyl alcohol film having a thickness of 75 μm, a permeability of 82%, a tensile strength of 0.06 GPa, and a tensile modulus of 2.5 GPa.

The polyvinyl alcohol film prepared above was fixed at a stretching temperature of 30 ° C. and stretched four times at a rate of 10 mm / min in a boric acid solution (2 to 4%) to obtain a thickness of 15 μm, a transmittance of 75%, a tensile strength of 0.3 GPa, and a tensile strength. A polyvinyl alcohol film having an elastic modulus of 8 GPa was obtained.

Example 8

Polyvinyl alcohol having a number average degree of polymerization of 1500, an alternating content of 54.0%, and a saponification degree of 99.0% of waste polyvinyl alcohol was mixed in a beaker at a concentration of 5.0 g / dl using water as a solvent and at 100 ° C. After dissolving completely for 2 hours to prepare a solution, it was poured into a stainless steel dish and dried under vacuum for 48 hours to obtain a polyvinyl alcohol film having a thickness of 75 μm, a permeability of 87%, a tensile strength of 0.04 GPa, and a tensile modulus of 2.2 GPa.

The polyvinyl alcohol film prepared above was fixed at a stretching temperature of 30 ° C. and stretched four times at a rate of 10 mm / min in a boric acid solution (2 to 4%) to obtain a thickness of 15 μm, a transmittance of 79%, a tensile strength of 0.22 GPa, and a tensile strength. A polyvinyl alcohol film having an elastic modulus of 6.8 GPa was obtained.

Example 9

Polyvinyl alcohol having a number average degree of polymerization of 1700, alternating sequencer content of 53.9%, and saponification degree of 99.0% of waste polyvinyl alcohol was mixed in a beaker at a concentration of 10.0 g / dl using water as a solvent and at 100 ° C. After completely dissolving for 2 hours to prepare a solution, it was poured into a stainless steel dish and dried under vacuum for 48 hours to obtain a polyvinyl alcohol film having a thickness of 85 μm, a transmittance of 80%, a tensile strength of 0.04 GPa, and a tensile modulus of 2 GPa.

The polyvinyl alcohol film prepared above was fixed at a stretching temperature of 30 ° C. and stretched four times at a rate of 10 mm / min in a boric acid solution (2 to 4%) to a thickness of 20 μm, a transmittance of 73%, a tensile strength of 0.2 GPa, and a tensile strength. A polyvinyl alcohol film having an elastic modulus of 6.5 GPa was obtained.

Example 10

Polyvinyl alcohol with a number average degree of polymerization of 1500, an alternating content of 54.0%, and a saponification degree of 99.0% of waste polyvinyl alcohol was mixed in a beaker at a concentration of 10.0 g / dl using water as a solvent. After completely dissolving for 2 hours to prepare a solution, it was poured into a stainless steel dish and dried under vacuum for 48 hours to obtain a polyvinyl alcohol film having a thickness of 85 μm, a transmittance of 85%, a tensile strength of 0.02 GPa, and a tensile modulus of 1.6 GPa.

The polyvinyl alcohol film prepared above was fixed at a stretching temperature of 30 ° C. and stretched four times at a rate of 10 mm / min in a boric acid solution (2 to 4%) to obtain a thickness of 20 μm, a transmittance of 76%, a tensile strength of 0.15 GPa, and a tensile strength. A polyvinyl alcohol film having an elastic modulus of 5.5 GPa was obtained.

Example 11

Polyvinyl alcohol having a number average degree of polymerization of 1700, alternating sequencer content of 53.9%, and saponification degree of 99.0% of waste polyvinyl alcohol was mixed in a beaker at a concentration of 20.0 g / dl using water as a solvent and at 100 ° C. After dissolving completely for 2 hours to prepare a solution, it was poured into a stainless steel dish and dried under vacuum for 48 hours to obtain a polyvinyl alcohol film having a thickness of 100 μm, a permeability of 74%, a tensile strength of 0.03 GPa, and a tensile modulus of 1.8 GPa.

The polyvinyl alcohol film prepared above was fixed at a stretching temperature of 30 ° C. and stretched four times at a rate of 10 mm / min in a boric acid solution (2 to 4%) to have a thickness of 30 μm, a transmittance of 70%, a tensile strength of 0.1 GPa, and a tensile strength. A polyvinyl alcohol film having an elastic modulus of 3.5 GPa was obtained.

Example 12

Polyvinyl alcohol with a number average degree of polymerization of 1500, an alternating content of 54.0%, and a saponification degree of 99.0% of waste polyvinyl alcohol was mixed in a beaker at a concentration of 20.0 g / dl using water as a solvent and at 100 ° C. After completely dissolving for 2 hours to prepare a solution, it was poured into a stainless steel dish and dried under vacuum for 48 hours to obtain a polyvinyl alcohol film having a thickness of 100 μm, a transmittance of 77%, a tensile strength of 0.01 GPa, and a tensile modulus of 1.2 GPa.

The polyvinyl alcohol film prepared above was fixed at a stretching temperature of 30 ° C. and stretched four times at a rate of 10 mm / min in a boric acid solution (2 to 4%) to have a thickness of 30 μm, a permeability of 72%, a tensile strength of 0.07 GPa, and a tensile strength. A polyvinyl alcohol film having an elastic modulus of 2.8 GPa was obtained.

Example 13

A polyvinyl alcohol film having a thickness of 70 μm, a transmittance of 85%, a tensile strength of 0.08 GPa, and a tensile modulus of 3 GPa of Example 1 was fixed at a stretching temperature of 10 ° C., at a rate of 10 mm / min in a boric acid solution (2 to 4%). The film was stretched 4 times to obtain a polyvinyl alcohol film having a thickness of 10 μm, a transmittance of 80%, a tensile strength of 0.3 GPa, and a tensile modulus of 9 GPa.

Example 14

A polyvinyl alcohol film having a thickness of 70 μm, a transmittance of 85%, a tensile strength of 0.08 GPa, and a tensile modulus of 3 GPa of Example 1 was fixed at a stretching temperature of 60 ° C., at a rate of 10 mm / min in a boric acid solution (2 to 4%). The film was stretched 4 times to obtain a polyvinyl alcohol film having a thickness of 10 µm, a transmittance of 72%, a tensile strength of 0.7 GPa, and a tensile modulus of 14 GPa.

Example 15

In order to dry-stretch the polyvinyl alcohol film having a thickness of 70 μm, a transmittance of 85%, a tensile strength of 0.08 GPa, and a tensile modulus of 3 GPa, the band was stretched once at a draw ratio of 30 ° C. at 4 times. A polyvinyl alcohol film having a thickness of 10 μm, a transmittance of 75%, a tensile strength of 0.55 GPa, and a tensile modulus of 12 GPa was obtained.

Example 16

In order to dry-stretch the polyvinyl alcohol film having a thickness of 70 μm, a transmittance of 85%, a tensile strength of 0.08 GPa, and a tensile modulus of 3 GPa, the band was stretched once at a draw ratio of 4 times at a stretching temperature of 60 ° C. A polyvinyl alcohol film having a thickness of 10 μm, a transmittance of 70%, a tensile strength of 0.8 GPa, and a tensile modulus of 13 GPa was obtained.

Comparative Example 1

Polyvinyl alcohol prepared by Dongyang Chemical was mixed in a beaker with water at a concentration of 2.5 g / dl as a solvent, completely dissolved at 100 ° C. for 2 hours to prepare a solution, and then poured into a stainless steel dish and dried under vacuum for 48 hours. Thus, a polyvinyl alcohol film having a thickness of 70 µm, a transmittance of 86%, a tensile strength of 0.05 GPa, and a tensile modulus of 2.5 GPa was obtained.

The polyvinyl alcohol film prepared above was fixed at a stretching temperature of 30 ° C. and stretched four times at a rate of 10 mm / min in a boric acid solution (2 to 4%) to have a thickness of 10 μm, a transmittance of 75%, a tensile strength of 0.4 GPa, and a tensile strength. A polyvinyl alcohol film having an elastic modulus of 6 GPa was obtained.

Comparative Example 2

Polyvinyl alcohol (Kuraray 117K) manufactured by Kuraray, Japan, was mixed in a beaker with water at a concentration of 2.5 g / dl as a solvent, completely dissolved at 100 ° C. for 2 hours to prepare a solution, and then poured into a stainless steel dish and vacuumed. The resultant was dried for 48 hours to obtain a polyvinyl alcohol film having a thickness of 70 μm, a transmittance of 89%, a tensile strength of 0.07 GPa, and a tensile modulus of 2.8 GPa.

The polyvinyl alcohol film prepared above was fixed at a stretching temperature of 30 ° C. and stretched four times at a rate of 10 mm / min in a boric acid solution (2 to 4%) to have a thickness of 10 μm, a transmittance of 76%, a tensile strength of 0.45 GPa, and a tensile strength. A polyvinyl alcohol film having an elastic modulus of 8 GPa was obtained.

The transmittance, tensile strength and tensile modulus of the polyvinyl alcohol films prepared in Examples 1-16 and Comparative Examples 1-2 are shown in Table 1 below.

Permeability (%) Tensile Strength (GPa) Tensile Modulus (GPa) Example One 77 0.5 11 2 83 0.4 9 3 84 0.1 3 4 88 0.06 2.5 5 80 0.2 6.5 6 86 0.15 5 7 75 0.3 8 8 79 0.22 6.8 9 73 0.2 6.5 10 76 0.15 5.5 11 70 0.1 3.5 12 72 0.07 2.8 13 80 0.3 9 14 72 0.7 14 15 75 0.55 12 16 70 0.8 13 Comparative example One 75 0.4 6 2 76 0.45 8

As shown in Table 1, in the case of Example 1-16 using waste polyvinyl alcohol, it could be confirmed that it has strength, elastic modulus and transparency comparable to Comparative Example 1-2 using commercially available polyvinyl alcohol.

The method of manufacturing the polyvinyl alcohol film of the present invention is possible to reduce the cost due to the recycling of resources by using waste polyvinyl alcohol, and to recover and recycle polyvinyl alcohol, which is a hardly decomposable substance, not only excellent in environmental protection, but also existing Has the effect of the invention to provide functionality such as excellent strength and elastic modulus, transparency to be used in place of the hybrid array polyvinyl alcohol.

Simple modifications and variations of the present invention can be readily used by those skilled in the art, and all such variations or modifications can be considered to be included within the scope of the present invention.

Claims (4)

Polyvinyl alcohol having molecular variables of number average polymerization degree 1,000 to 2,000 obtained from waste polyvinyl alcohol, content of alternating diad group content of 50 to 55% and saponification degree of 80.0 to 99.9% in water at a concentration of 0.1 to 20 g / dl Dissolve; Forming a film by forming the dissolved polyvinyl alcohol; And Wet stretching the prepared film at 10 to 60 ° C .; Method for producing a polyvinyl alcohol film, characterized in that consisting of steps. delete The method for producing a polyvinyl alcohol film according to claim 1, wherein the wet stretching is performed 3 to 5 times in a boric acid solution (2 to 4 wt%) at a stretching temperature of 10 to 60 ° C. delete