KR0179940B1 - Method of manufacturing polyvinylalcohol film - Google Patents

Abstract

A method for producing a high-shift array high molecular weight polyvinyl alcohol film is disclosed.

In the method of the present invention, a number average degree of polymerization of 2,500 to 22,000 obtained by saponifying various poly (vinyl pivalates) obtained by polymerizing vinyl pivalate under various conditions, and the content of alternating diad groups 55 High syndiotactic high molecular weight and ultra high molecular weight polyvinyl alcohols having various molecular variables of ˜65% and saponification degree 90.0 to 99.9% were either dimethylsulfoxide (DMSO) alone or dimethylsulfoxide (DMSO) / The film prepared by dissolving at a concentration of 0.1 to 5 g / dl in a water mixed solvent and then forming a film is characterized in that the film is once drawn or cold drawn at 25 ° to 230 ° C. and then drawn at 25 ° to 230 ° C. .

According to the present invention, a polyvinyl alcohol film having strength, modulus of elasticity and orientation comparable to that of a film having a high draw ratio by multi-step drawing such as polyethylene in a single drawing by applying a high temperature strip drawing method without thermal decomposition or side reaction is provided. It is effective.

Description

[Name of invention]

Manufacturing method of high alternating high molecular weight polyvinyl alcohol film and film

Detailed description of the invention

[Background of invention]

1) Technical Field

The present invention relates to a method for producing a poly (vinyl alcohol) film and a film produced by the method, and more particularly, high alternating ultrahigh molecular weight having a very high molecular weight and syndiotacticity. The present invention relates to a method for producing a film having high orientation, high strength, and high modulus using polyvinyl alcohol, and a film produced thereby.

2) prior art

Polyvinyl alcohol was the first in 1924 during the saponification of poly (vinyl acetate) by Herrmann and Haehnel of Germany (WOHerrmann and W. Hachnel, German Patent, 450,286 (1924)). Found. In addition to polyvinyl acetate, polyvinyl alcohol is a polymer prepared by saponifying various types of polyvinyl esters and polyvinyl ethers polymers. According to the stereoregrularity and degree of saponification, it is a very useful polymer which is widely used in the manufacture of resins, clothing fibers, industrial fibers, food packaging films, liquid and gas separation membranes, polarizing films and medical polymer materials. In order for fibers or membranes obtained from polyvinyl alcohol to have excellent physical properties (orientation, strength, elastic modulus, crystallinity, etc.), solvent resistance, and alkali resistance, polyvinyl alcohol having high molecular weight, alternating arrangement, and saponification degree should be used as the material. M. Masuda, Polyvinyl Alcohol-Developments (CAFinch Ed.), Pp. 403-422, John Wiley and Sons, New York, 1991.

The method of producing fibers and films with high strength and elastic modulus has been widely studied in the past. These studies have transformed the polymer chains forming the fibers or films into a crystallographic region that is ideally fully unfolded by stretching by physical external force. If possible, it is based on the fact that it is possible to substantially produce fibers or membranes having the inherent (ultimate) strength and intrinsic (ultra) crystalline lattice modulus of the polymer.

In the case of polyethylene, the elastic modulus of the fiber obtained therefrom was over 200 GPa, which resulted in a close to the ultimate crystalline modulus of elasticity of the material [M. Matsuo, I. Inouc, and N. Abumiya, Sen-i Gakkaish, 36, 696 (1984)] This is not only a result of stretching the stretchable polyethylene fiber hundreds of times, but also has a high glass transition temperature and melting point compared to other polymers, and thus has a high strength and high modulus. It has been quite limited. Therefore, the study of sufficiently orienting other crystalline polymers such as polyester, polyamide, polyacrylonitrile and polyvinyl alcohol can be considered to be of great importance.

Among these polymers, polyvinyl alcohol has an extreme modulus of 236 GPa, which is similar to polyethylene, and thus attracts attention as a high strength and high modulus polymer material [M. Matsuo, Y. Harashina, and T.Ogita, Polym.J., 25 , 319 (1993)] Due to the strong intermolecular and intramolecular hydrogen bonds in the adjacent hydroxy period, it is difficult to orient the polymer chain sufficiently by the general drawing method, so that the drawability is not good and the inherent extreme physical properties are difficult to express due to these disadvantages. [YSChoi, Y.Oishi, and K.Miyasaka, Polym. J., 22.601 (1990)]. In other words, it is difficult to completely unfold the polymer chain. To overcome this, the gel stretching method [D.T.Grubb and F.R.Kearney, J. Appl. Polym. Sci, 37, 695 (1990)], single crystal mat stretching method [T.Kanamoto, S. Kiyooka, Y. Tomasmasyan, H. Sano, and H. Narukawa, Polymer, 31, 2039 (1990)] and high temperature band stretching method T. Kunugi, T. Kawasumi, and T. Ito, J. Appl. Polym. Sci, 40, 2101 (1990)].

Among these methods, the high temperature band stretching method has the advantage of less chain folding, less pyrolysis, and no chemicals than the general thermal stretching method because the sample is stretched by receiving heat in a localized region. Kiho and Asai [H.Kiho and K.Asia, Kobunshi Toronkai Preprint (Japan), p. 835, 1974] have used this method for the first time in polyethylene fibers, such as Kamezawa et al. Kamezawa, M.Yamada, and M. Takayanagi, J. Appl. Polym. Sci., 24, 1227 (1979)], Yamada et al., K. Yamada, M. Kamezawa, and M. Takayanagi, J. Appl. Polym. Sci., 26, 49 (1981)], Kunugi et al. [T.Kunugi, O.Ohmori, and S.Mikami, Polymer, 29, 814 (1988)] and Takahashi et al. [T.Takahashi, et al. , T.Tanaka, T.Kamei, N.Okui, M.Takahiro, S.Umemoto, and T.Sakai, Kobunshi Ronbunshu, 44, 65 (1988)] have described this method as polyethylene, polypropylene, nylon, polyethylene terephthalate. Applied to.

Band stretching of polyvinyl alcohol (PVA) gels or fibers is described by Garrett and Groub (PDGarrett and DTGrubb, Polym, Comm, 29, 60 (1988)) and Kunugi et al. Kunugi, T. Kawasumi, and T. Ito, J. Appl. Polym. Sci., 40, 2101 (1990). Garrett and Grobb banded polyvinyl alcohol fibers with a number average degree of polymerization of 2,000 to produce fibers having a tensile strength of 0.5 GPa. Kunugi et al., T. Kunugi, T. Kawasumi, and T. Ito, J. Appl. Polym. Sci., 40, 2101 (1990)] prepared polyvinyl alcohol fibers having a tensile strength of 2.4 GPa by band stretching polyvinyl alcohol fibers with a number average degree of polymerization of 10,000.

Stretchability of polymer membranes 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. Bastiaansen, 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 The concentration of the polymer solution (T. Kanamoto, A. Tsurata, K. Tanaka, and RSPorter, Polym, J., 15, 327 (1983)) is affected. 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.

[Summary of invention]

An object of the present invention is to apply a high-temperature strip stretching method of high alternating ultra high molecular weight polyvinyl alcohol film to increase the draw ratio and eliminate various side effects that may be caused by thermal stretching, rather than the conventional thermal stretching method, tensile strength or tensile modulus It is to provide a high strength high modulus polyvinyl alcohol film having excellent physical properties.

Another object of the present invention to provide a high-strength high modulus polyvinyl alcohol film showing the optimum physical properties by maximizing the draw ratio during hot strip stretching at the optimum film concentration selected in consideration of the film formation concentration affecting the draw ratio.

The method of manufacturing a high-shift high molecular weight polyvinyl alcohol film according to the present invention is a number average obtained by saponifying various poly (vinyl pivalates) obtained by polymerizing vinyl pivalate under various conditions. High syndiotactic high molecular weight and ultra high molecular weight polyvinyl alcohols having various molecular variables of 2,500 to 22,000 degree of polymerization, 55 to 65% of alternating diad group content, and 90.0 to 99.9% of saponification degree, may be used as dimethyl sulfoxide (DMSO). ) The film prepared by dissolving at a concentration of 0.1 to 5 g / dl alone or in dimeltyl sulfoxide (DMSO) / water mixed solvent and then forming the film was subjected to one band stretching or cold stretching at 25 ° to 230 ° C. and then 25 ° to It is characterized by strip stretching at 230 ° C.

[Detailed Description of the Invention]

The present invention will be described in more detail below.

The manufacturing method of the high alternating ultra high molecular weight polyvinyl alcohol film of the present invention has a big difference from the two known manufacturing processes.

Compared with the existing manufacturing methods are as follows.

First, the conventional polyvinyl alcohol film is made of a hybrid high molecular weight and ultra high molecular weight polyvinyl alcohol having an alternating content of 47 to 53%, a number average degree of polymerization of 1,500 to 15,000.

The physical properties and orientation of the film made from polyvinyl alcohol, such as tensile strength and tensile modulus, increase with increasing molecular weight and alternating content of polyvinyl alcohol. Therefore, in order to effectively raise such physical properties and orientations from a relatively low draw ratio, high alternating high molecular weight and ultra high molecular weight polyvinyl alcohols having a content of 55% or more in alternator, a number average degree of polymerization of 2,500 or more were used as raw materials of the film. .

Second, in order to manufacture a polyvinyl alcohol film at an optimum drawing ratio, it is necessary to consider its optimum film concentration, but the existing methods do not consider this, which is generally used to obtain the optimum tangle concentration of the chain. This is because the viscosity measurement method was difficult to apply because of the nonuniformity of the polyvinyl alcohol solution. Especially in the case of high-shift polyvinyl alcohol solution, even in lean concentration, pseudoplastic and shear thinning phenomenon occur. So, the solution is very unstable [Ryu Won-seok, Ph.D. Thesis, Seoul National University, 1994] It is impossible to predict the optimal deposition concentration by the method. In the present invention, in order to effectively consider the film formation concentration, the polyvinyl alcohol formed by each concentration band is drawn once to estimate the concentration showing the maximum draw ratio inversely, thereby obtaining the optimum physical properties and orientation from the sample used in the present invention. Film forming conditions of the film were established.

Third, the thermal stretching method, which is generally known as a method of stretching the membrane, could not effectively increase the draw ratio in the case of polyvinyl alcohol, and had side effects such as yellowing and refolding accompanied with thermal decomposition of the membrane. In the case of the band stretching, an example of application to a hybrid array polyvinyl alcohol film and a fiber has been reported, but no application is applied to an alternating polyvinyl alcohol membrane. In the present invention, a high-stretch high-molecular weight and ultra-high molecular weight polyvinyl alcohol film is stretched at a high temperature so as to be stretched once without undergoing a complicated stretching process such as the multi-step stretching method (4 to 5 or more times) applied to a polyethylene film. A polyvinyl alcohol film having sufficient stretching ratio to obtain an orientation degree and a crystal orientation index corresponding thereto as a sufficient stretching to obtain an orientation degree and a crystal orientation index.

Hereinafter, specific examples of the present invention and comparative examples for comparison will be described. However, the following examples are merely for illustrative purposes and should not be understood as limiting the scope of the invention.

Example 1

A polyvinyl alcohol having a number average degree of polymerization of 12,300, an alternator content of 63.4%, and a saponification degree of 99.9% was mixed at a concentration of 0.2 g / dl at 110 ° C using a solvent in which dimethyl sulfoxide (DMSO) / water was mixed at a ratio of 9/1. It was completely dissolved in C for 5 hours, poured into a stainless steel dish, and completely dried under vacuum to obtain a polyvinyl alcohol film. This membrane was once stretched at 220 ° C. to prepare a stretched polyvinyl alcohol film.

Example 2

Polyvinyl alcohol with a number average degree of polymerization of 12,300, 63.4% of alternator and 99.9% of saponification degree, was dissolved completely in DMSO as a solvent at 0.3 g / dl for 5 hours at 110 ° C, and poured into a stainless steel dish under vacuum. Drying completely gave a polyvinyl alcohol film. This film was stretched once at 220 ° C to prepare a stretched polyvinyl alcohol film.

Example 3

Polyvinyl alcohol with a number average degree of polymerization of 12,300, alternating content of 63.4%, and saponification degree of 99.9% was dissolved in DMG as a solvent at 0.4 g / dl for 5 hours at 110 ° C, then poured into a stainless steel dish under vacuum. Drying completely gave a polyvinyl alcohol film. This film was stretched once at 220 ° C to prepare a stretched polyvinyl alcohol film.

Example 4

Polyvinyl alcohol with a number average degree of polymerization of 17,100, 63.9% of alternator, and 99.5% of saponification degree was dissolved completely in DMSO as a solvent at a concentration of 0.2 g / dl for 5 hours at 110 ° C, and poured into a stainless steel dish under vacuum. Drying completely gave a polyvinyl alcohol film. This film was stretched once at 220 ° C to prepare a stretched polyvinyl alcohol film.

Example 5

Polyvinyl alcohol with a number average degree of polymerization of 15,500, 58.5% of alternator and 99.7% of saponification degree, was dissolved completely in DMSO as a solvent at 0.4 g / dl for 5 hours at 110 ° C, and poured into a stainless steel dish under vacuum. Drying completely gave a polyvinyl alcohol film. This film was stretched once at 220 ° C to prepare a stretched polyvinyl alcohol film.

Example 6

Polyvinyl alcohol with a number average degree of polymerization of 15,100, 63.5% of alternator, and 95.4% of saponification degree was dissolved completely with DMSO at a concentration of 0.3 g / dl for 5 hours at 110 ° C, and poured into a stainless steel dish under vacuum. Drying completely gave a polyvinyl alcohol film. This film was stretched once at 220 ° C to prepare a stretched polyvinyl alcohol film.

Example 7

Polyvinyl alcohol with a number average degree of polymerization of 12,300, 63.4% of alternator and 99.9% of saponification degree, was dissolved completely in DMSO as a solvent at 0.3 g / dl for 5 hours at 110 ° C, and poured into a stainless steel dish under vacuum. Drying completely gave a polyvinyl alcohol film. This film was band drawn once at 200 ° C. to prepare a stretched polyvinyl alcohol film.

Example 8

Polyvinyl alcohol with a number average degree of polymerization of 12,300, alternator content of 63.4%, and saponification degree of 99.9% was used at a concentration of 0.3 g / dl in DMSO water at a ratio of 9/1 for 5 hours at 110 ° C. After melting, it was poured into a stainless steel dish and completely dried under vacuum to obtain a polyvinyl alcohol film. This film was stretched once at 220 ° C to prepare a stretched polyvinyl alcohol film.

Example 9

Polyvinyl alcohol with a number average degree of polymerization of 12,300, alternator content of 63.4%, and saponification degree of 99.9% at a concentration of 0.3 g / dl was mixed with a solvent of DMSO / water at an ratio of 8/2 for 5 hours at 110 ° C. After melting completely, it was poured into a stainless steel dish and completely dried under vacuum to obtain a polyvinyl alcohol film. This film was stretched once at 220 ° C to prepare a stretched polyvinyl alcohol film.

Example 10

Polyvinyl alcohol with a number average degree of polymerization of 12,300, 63.4% of alternator and 99.9% of saponification degree, was dissolved completely in DMSO as a solvent at 0.3 g / dl for 5 hours at 110 ° C, and poured into a stainless steel dish under vacuum. Drying completely gave a polyvinyl alcohol film. The film was cold drawn once at room temperature and then stripped once at 220 ° C. to prepare a stretched polyvinyl alcohol film.

Example 11

Polyvinyl alcohol with a number average degree of polymerization of 12,300, 63.4% of alternator and 99.9% of saponification degree, was dissolved completely in DMSO as a solvent at 0.3 g / dl for 5 hours at 110 ° C, and poured into a stainless steel dish under vacuum. Drying completely gave a polyvinyl alcohol film. The film was cold drawn once at room temperature and then stripped once at 220 ° C. to prepare a stretched polyvinyl alcohol film.

Example 12

Polyvinyl alcohol with a number average degree of polymerization of 12,300, alternator content of 63.4%, and saponification degree of 99.9% at a concentration of 0.3 g / dl was mixed with a solvent of DMSO / water at an ratio of 8/2 for 5 hours at 110 ° C. After melting completely, it was poured into a stainless steel dish and completely dried under vacuum to obtain a polyvinyl alcohol film. The film was cold drawn once at room temperature and then stripped once at 220 ° C. to prepare a stretched polyvinyl alcohol film.

Comparative Example 1

Polyvinyl alcohol having a number average degree of polymerization of 4,500, alternating content of 51.5%, and saponification degree of 99.9% was dissolved completely in DMSO as a solvent at a concentration of 2.7 g / dl for 5 hours at 110 ° C, and poured into a stainless steel dish under vacuum. Drying completely gave a polyvinyl alcohol film. The film was hot-stretched once at 220 ° C. to prepare a stretched polyvinyl alcohol film.

Comparative Example 2

Polyvinyl alcohol with a number average degree of polymerization of 1,500, alternator content of 50.2%, and saponification degree of 99.9% was dissolved in DMSO as a solvent at a concentration of 10.5 g / dl for 5 hours at 110 ° C, then poured into a stainless steel dish under vacuum. Drying completely gave a polyvinyl alcohol film. The film was hot-stretched at 150 ° C. once to prepare a stretched polyvinyl alcohol film.

Comparative Example 3

Polyvinyl alcohol with a number average degree of polymerization of 12,300, 63.4% of alternator and 99.9% of saponification degree, was dissolved completely in DMSO as a solvent at 0.3 g / dl for 5 hours at 110 ° C, and poured into a stainless steel dish under vacuum. Drying completely gave a polyvinyl alcohol film. The film was cold drawn once at room temperature to prepare a stretched polyvinyl alcohol film.

[Comparative Example 4]

Polyvinyl alcohol with a number average degree of polymerization of 4,500, alternator content 63.4%, and saponification degree 99.9% was dissolved in DMSO as a solvent at a concentration of 0.3 g / dl for 5 hours at 110 ° C and poured into a stainless steel dish under vacuum. Drying completely gave a polyvinyl alcohol film. The film was thermally stretched once at 120 ° C. to produce a stretched polyvinyl alcohol film.

The properties of the polyvinyl alcohol films prepared by Examples 1 to 12 and Comparative Examples 1 to 4 are as shown in the following [Table 1].

As described above, according to the present invention, by applying a high temperature strip drawing method without thermal decomposition or side reaction, the high shift having strength, elastic modulus and orientation degree comparable to a film having a high draw ratio by multi-step drawing such as polyethylene in a single drawing by one drawing. There is an effect that an array ultra high molecular weight polyvinyl alcohol film is provided.

Therefore, the polyvinyl alcohol film of the present invention is a high strength and high modulus film, a highly oriented polarizing film for electronic materials, food and pharmaceutical packaging film having excellent oxygen permeability due to the high orientation of the chain and various molecular variables (molecular weight, alternating) Arrangement and degree of saponification) can be used as materials such as various gas and liquid separation membranes that can be obtained. In the case of the hybrid array polyvinyl alcohol film, since the vinyl alcohol unit is a hybrid array, the wet strength is not very good, and the use range of industrially is very limited as a single membrane, so that the ethylene / vinyl alcohol copolymer film is used as a separator, food and pharmaceutical packaging film. It is a high syndiotactic polyvinyl alcohol film whose wet strength, water resistance, and oxygen permeability are incomparable to those of atactic polyvinyl alcohol films due to its molecular characteristics in view of the mass market. It is thought that it will be able to replace ethylene / vinyl alcohol copolymer film which is in high demand worldwide.

Although the present invention has been described in detail only with respect to the described embodiments, it will be apparent to those skilled in the art that various modifications and changes are possible within the technical scope of the present invention, and such modifications and modifications belong to the appended claims.

Claims (2)

Number average degree of polymerization 2,500 to 22,000 obtained by saponifying various poly (vinyl pivalates) obtained by polymerizing vinyl pivalate under various conditions, 55 to 65% of alternating diad group content, and saponification. High syndiotactic high molecular weight and ultra high molecular weight polyvinyl alcohols having various molecular variables of 90.0 to 99.9% were prepared in dimethyl sulfoxide (DMSO) alone or dimethyl sulfoxide (DMSO) / water mixed solvent. The high-molecular array high molecular weight polyvinyl, characterized in that the film prepared by melting at a concentration of ~ 5g / dl and then formed into a film and then band-stretched or cold-stretched at 25-230 ° C once and then stretched at 25-230 ° C. Method for producing an alcohol film. A polyvinyl polymer prepared by the method of claim 1, comprising a high average molecular weight polyvinyl alcohol having a high average molecular weight of 2,500 to 22,000, an alternating diad group content of 55 to 65%, and a saponification degree of 90.0 to 99.9%. Alcohol film.