KR20130051934A - Polyvinyl alcohol film - Google Patents

Abstract

This invention is a polyvinyl alcohol polymer film containing 0.001-1 mass part of surfactant (B) with respect to 100 mass parts of polyvinyl alcohol polymers (A) and the said polyvinyl alcohol polymers (A), Polyvinyl alcohol polymer film whose color of the film is less likely to be yellow even after storage for about several months in a temperature-controlled warehouse at a temperature of about 20 to 8.0 at a temperature of 2.0 to 8.0 when dissolved at a concentration of mass%. For the purpose of providing It is preferable that the said polyvinyl alcohol-type polymer film was obtained using an acidic substance (C).

Description

Polyvinyl alcohol polymer film {POLYVINYL ALCOHOL FILM}

This invention relates to a polyvinyl alcohol (Hereinafter, "polyvinyl alcohol" may be abbreviated as "PVA") type | system | group polymer film, its manufacturing method, and the storage method of the said PVA-type polymer film.

PVA-based polymer films formed using PVA-based polymers utilize the unique property of water solubility and various other excellent physical properties, so that optical applications such as polarizing film manufacturing raw materials, packaging applications for chemicals such as pesticides and detergents, and textile products It is used for various uses, such as a packaging use.

By the way, the method of mix | blending a nonionic surfactant as a method of suppressing generation | occurrence | production of the die line and the generation of a foreign material at the time of forming a PVA polymer film into a film using T die etc., and improving film forming property is proposed (patent See Document 1). In addition, as a method of providing a PVA-based polymer film having excellent optical properties without optical streaks, optical color irregularities, and the like, which exhibits excellent blocking resistance, a method of blending a plurality of specific surfactants has been proposed (patent See Document 2.

Japanese Laid-Open Patent Publication 2001-253993 Japanese Laid-Open Patent Publication 2005-206809

However, when the PVA-based polymer film prepared by blending the surfactant was rolled into a roll and stored for several months in a warehouse where the temperature was controlled at around room temperature, the color of the roll was remarkably yellow. It has been revealed. This yellowing has little effect on the physical properties such as mechanical strength, stretchability, haze, etc. of the PVA polymer film, but when used as a packaging material, the color of the contents is yellow or used as a raw material when manufacturing a polarizing film. There was a possibility that the light transmitted through the polarizing film obtained in this case had a yellow color, and thus gave a bad impression to consumers and users.

An object of the present invention is to provide a PVA-based polymer film in which the color of the film is less likely to have a yellow color even after being stored for several months in a warehouse that has been temperature-controlled at room temperature.

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining in order to achieve the said objective, as a result, as a PVA-type polymer film containing a PVA-type polymer and surfactant, when it melt | dissolves in water, the PVA-type polymer film has a fixed range. It was found out that the above object was achieved, and further studies were completed based on the findings to complete the present invention.

That is,

[1] A PVA-based polymer film containing from 0.001 to 1 parts by mass of a surfactant (B) with respect to PVA-based polymer (A) and 100 parts by mass of the PVA-based polymer (A), at a concentration of 7% by mass in water. PVA system polymer film whose pH at 20 degreeC when melt | dissolved is 2.0-8.0,

[2] The PVA polymer film of the above [1], wherein the saponification degree of the PVA polymer (A) is 90 mol% or more,

[3] the PVA polymer film of the above-mentioned [1] or [2], obtained by using an acidic substance (C);

[4] The PVA polymer film of the above [3], wherein the acidic substance (C) has a pKa (acid dissociation constant) of 25 or more at 3.5 ° C and a boiling point of more than 120 ° C under normal pressure of the acidic substance (C);

[5] the PVA polymer film according to any one of the above [1] to [4], wherein the surfactant (B) is a nonionic surfactant;

[6] The PVA polymer film of the above [5], wherein the nonionic surfactant is an alkanolamide-type surfactant;

[7] The PVA polymer film according to any one of the above [1] to [6], containing 0.01 to 3% by mass of the antioxidant (D) with respect to the surfactant (B),

[8] a step of preparing a film forming undiluted solution containing 0.001 to 1 parts by mass of surfactant (B) based on 100 parts by mass of the PVA polymer (A) and the PVA polymer (A); and a process of forming the film forming undiluted solution The manufacturing method of the PVA-type polymer film in any one of said [1]-[7] containing the said film forming undiluted | stock solution obtained using the mixture containing 70 mass% or more of surfactants (B),

[9] The method for producing the above [8], wherein the film forming undiluted solution is obtained using an acidic substance (C).

[10] The production method of [8] or [9], wherein the pH at 20 ° C when the mixture is dissolved in water at a concentration of 0.1% by mass is 8.0 or more;

[11] A method for storing a PVA-based polymer film, wherein the PVA-based polymer film according to any one of [1] to [7] is stored under a temperature of 0 to 40 ° C. and a humidity of 75% RH or less. .

Even if the PVA-based polymer film of the present invention is stored for a long time in a warehouse or the like, the color of the film is hardly yellow. Therefore, even when the said PVA-type polymer film is used as a raw material at the time of manufacturing a packaging material or a polarizing film, it is hard to give a bad impression to a consumer and a user. Moreover, according to the manufacturing method of this invention, said PVA type polymer film can be manufactured easily and inexpensively.

Furthermore, when the PVA-based polymer film is stored by the storage method of the present invention, yellowing of the film can be more effectively suppressed.

The present invention will be described in more detail below.

The PVA-based polymer film of the present invention contains a PVA-based polymer (A) and a surfactant (B).

As a PVA-type polymer (A), what was manufactured by saponifying the vinyl ester type polymer obtained by superposing | polymerizing a vinyl ester type monomer can be used. Examples of the vinyl ester monomers include vinyl formate, vinyl acetate, vinyl propionate, vinyl valerate, vinyl laurate, vinyl stearate, vinyl benzoate, vinyl pivalate, and vinyl versatate. Among these, vinyl acetate is preferable.

It is preferable that the said vinyl ester type polymer is obtained using only 1 type, or 2 or more types of vinyl ester type monomers as a monomer, and it is more preferable that it was obtained using only 1 type of vinyl ester type monomers as a monomer, but 1 type or 2 types The copolymer of the above-mentioned vinyl ester type monomer and the other monomer copolymerizable with this may be sufficient.

As another monomer copolymerizable with such a vinyl ester monomer, it is ethylene; Olefins having 3 to 30 carbon atoms such as propylene, 1-butene and isobutene; Acrylic acid or a salt thereof; Acrylic esters such as methyl acrylate, ethyl acrylate, n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, i-butyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate and octadecyl acrylate; Methacrylic acid or salts thereof; Methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, i-propyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, t-butyl methacrylate, 2-methacrylate Methacrylic acid esters such as ethylhexyl, dodecyl methacrylate and octadecyl methacrylate; Acrylamide, N-methylacrylamide, N-ethyl acrylamide, N, N-dimethylacrylamide, diacetone acrylamide, acrylamidepropanesulfonic acid or salts thereof, acrylamidopropyldimethylamine or salts thereof, An acrylamide derivative such as an amide or a derivative thereof; Methacrylamide, N-methyl methacrylamide, N-ethyl methacrylamide, methacrylamide propanesulfonic acid or a salt thereof, methacrylamide propyldimethylamine or a salt thereof, N-methylol methacrylamide or a derivative thereof Acrylamide derivatives; N-vinylamides, such as N-vinylformamide, N-vinylacetamide, and N-vinylpyrrolidone; Vinyl such as methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, i-propyl vinyl ether, n-butyl vinyl ether, i-butyl vinyl ether, t-butyl vinyl ether, dodecyl vinyl ether, stearyl vinyl ether Ether; Vinyl cyanide such as acrylonitrile and methacrylonitrile; Vinyl halides such as vinyl chloride, vinylidene chloride, vinyl fluoride and vinylidene fluoride; Allyl compounds such as allyl acetate and allyl chloride; Maleic acid or its salts, esters or acid anhydrides; Itaconic acid or its salt, ester or acid anhydride; Vinylsilyl compounds such as vinyltrimethoxysilane; Isopropenyl acetate etc. are mentioned. Said vinyl ester polymer can have a structural unit derived from 1 type (s) or 2 or more types of monomers other than these.

It is preferable that it is 15 mol% or less based on the number-of-moles of all the structural units which comprise a vinyl ester polymer, and, as for the ratio of the structural unit derived from the said other monomer in the said vinyl ester polymer, it is more preferable that it is 5 mol% or less. .

Although there is no restriction | limiting in particular in the polymerization degree of a PVA-type polymer (A), It is preferable that it is 200 or more from a point of film strength, etc., It is more preferable to exist in the range of 200-15,000, It is still more preferable to exist in the range of 300-5,000. The degree of polymerization herein means the average degree of polymerization measured according to the description of JIS K 6726-1994, and the ultimate viscosity measured in water at 30 ° C. after re-saponifying and purifying the PVA polymer (unit: deciliter / g ) Is obtained by the following equation.

Po = ([η] × 10 ³ /8.29) ^{(1 / 0.62)}

Moreover, it is preferable that it is 90 mol% or more, and, as for the saponification degree of a PVA-type polymer (A), it is more preferable that it is 93 mol% or more. When saponification degree is less than 90 mol%, there exists a possibility that the water resistance and durability of a PVA-type polymer film may become inadequate. Here, the degree of saponification of the PVA polymer is based on the total moles of the structural units (typically vinyl ester monomer units) and vinyl alcohol units that the PVA polymer has can be converted to vinyl alcohol units by saponification. The ratio (mol%) which the mole number of occupies says. The degree of saponification of the PVA-based polymer can be measured in accordance with the description of JIS K 6726-1994.

When manufacturing the PVA-based polymer film of the present invention, one kind of PVA-based polymer may be used alone as the PVA-based polymer (A), and two or more kinds of PVA-based polymers different in polymerization degree, saponification degree, or degree of modification, etc. are blended. May be used. Provided that the PVA-based polymer film of the present invention has an acidic functional group such as a carboxyl group and a sulfonic acid group; PVA system polymer which has an acid anhydride group; PVA-type polymer which has basic functional groups, such as an amino group; When PVA system polymer which has a functional group which accelerates a crosslinking reaction, such as these neutralizations, is contained, the secondary workability of a PVA system polymer film may fall by the crosslinking reaction between PVA system polymer molecules. Therefore, especially in the case where the outstanding secondary workability represented by optical use is required, etc., a PVA-type polymer film is a PVA type polymer which has an acidic functional group, a PVA type polymer which has an acid anhydride group, a PVA type polymer which has a basic functional group, and these It is preferable that it does not contain any of the neutralization of the PVA system polymer and / or vinyl ester system monomer manufactured by saponifying the vinyl ester polymer obtained by using only a vinyl ester monomer as a monomer as a PVA polymer (A). More preferably only a PVA polymer produced by saponifying a vinyl ester polymer obtained by using only ethylene and / or an olefin having 3 to 30 carbon atoms as a monomer, and only a vinyl ester monomer as the PVA polymer (A). By saponifying the vinyl ester polymer obtained by using More preferably, it contains only the prepared PVA-based polymer.

Although there is no restriction | limiting in particular in the kind of surfactant (B) used by this invention, For example, anionic surfactant and nonionic surfactant are mentioned.

As an anionic surfactant, For example, Carboxylic acid types, such as potassium laurate; Sulfate ester types such as octyl sulfate; Sulfonic acid types such as dodecylbenzenesulfonate, and the like.

As nonionic surfactant, For example, Alkyl ether type, such as polyoxyethylene oleyl ether; Alkyl phenyl ether types, such as polyoxyethylene octyl phenyl ether; Alkyl ester types such as polyoxyethylene laurate; Alkyl amine types, such as polyoxyethylene lauryl amino ether; Alkyl amide type, such as polyoxyethylene lauric acid amide; Polypropylene glycol ether types such as polyoxyethylene polyoxypropylene ether; Alkanolamide types such as lauric acid ethanolamide and oleic acid diethanolamide; And allyl phenyl ether types such as polyoxyalkylene allyl phenyl ether.

Surfactant may be used individually by 1 type, and may use 2 or more types together. Among these surfactants, nonionic surfactants are preferred because they are excellent in reducing the film surface abnormality at the time of film forming. Furthermore, alkanolamide-type surfactants are more preferable in that the effect of the present invention is more marked. Preferably, dialkanolamide (for example, diethanolamide, etc.) of aliphatic carboxylic acid (for example, C8-30 saturated or unsaturated aliphatic carboxylic acid etc.) is more preferable.

Since surfactant (B) is easy to obtain and inexpensive, it is preferable to use it in the form of the mixture containing surfactant (B). It is preferable that the content rate of surfactant (B) in the said mixture is 70 mass% or more, It is more preferable that it is 80 mass% or more, It is further more preferable that it is 90 mass% or more. Moreover, as an upper limit of the content rate of surfactant (B) in the said mixture, 99.99 mass% is mentioned, for example. Although there is no restriction | limiting in particular in components other than surfactant (B) which the said mixture contains, For example, the raw material, catalyst, solvent which were used when manufacturing surfactant (B); Decomposition products formed by decomposition of the surfactant (B); Stabilizers etc. which are added in order to improve stability of surfactant (B) are mentioned, More specifically, when surfactant (B) is an alkanolamide type nonionic surfactant, the corresponding alkanolamine is used. Can be mentioned.

Since the mixture containing the said surfactant (B) shows the effect of this invention more remarkably, when it melt | dissolves in the density | concentration of 0.1 mass% in water, the pH at 20 degreeC (the pH of the aqueous solution obtained) is 8.0 or more. It is preferable to become it, and it is more preferable to become in the range of 8.5-12.0. Moreover, when the mixture containing surfactant (B) is added to water so that it may become 0.1 mass%, and it stirs (you may further heat and / or cool as needed), and when temperature is maintained at 20 degreeC after that, Even when a part of the component contained in the mixture containing the surfactant (B) is not completely dissolved and is in the form of a dispersion, the value obtained by measuring the pH of the dispersion can be regarded as the above pH. .

The content of the surfactant (B) in the PVA-based polymer film needs to be in the range of 0.001 to 1 parts by mass with respect to 100 parts by mass of the PVA-based polymer, preferably in the range of 0.01 to 0.7 parts by mass, and in the range of 0.05 to 0.5 parts by mass. It is more preferable to be inside. When the said content rate is less than 0.001 mass part, the reducing effect more than the film surface at the time of film forming is hard to appear, and when it is more than 1 mass part, it elutes on the film surface, it becomes a cause of blocking, and handleability falls.

In the PVA-based polymer film of the present invention, the pH at 20 ° C. (the pH of the resulting aqueous solution) when dissolved in water at a concentration of 7% by mass is within the range of 2.0 to 8.0 to suppress yellowing of the film during long-term storage. very important. When said pH is less than 2.0, the yellowing considered to be due to deterioration of the PVA-type polymer itself becomes easy to generate | occur | produce. Moreover, the film whose said pH is less than 2.0 requires the special film forming equipment which carried out the antiseptic process at the time of film forming. From this viewpoint, it is preferable that said pH is 2.5 or more, and it is more preferable that it is 3.0 or more. On the other hand, when said pH exceeds 8.0, sufficient yellowing inhibitory effect is not acquired. From this point of view, the pH is preferably 7.5 or less, more preferably 7.0 or less, still more preferably 6.8 or less, particularly preferably 6.5 or less, and most preferably 6.0 or less. In addition, the PVA-based polymer film is added to water so as to be 7% by mass, and stirred (you may further heat and / or cool down if necessary). Even when a part of the component to be contained is not completely dissolved and is in the form of a dispersion, the value obtained by measuring the pH of the dispersion can be regarded as the above pH.

Although the method of controlling the pH at 20 degreeC when it melt | dissolves in water at the density | concentration of 7 mass% with respect to the PVA-type polymer film of this invention in the range of 2.0-8.0 is not necessarily limited, PVA system from the point which is easy to control. The method of mix | blending an appropriate amount of acidic substance (C) in the manufacturing process of a polymer film is preferable.

Although there is no restriction | limiting in particular in the kind of acidic substance (C), It is preferable that it is an acidic substance whose pKa (acid dissociation constant) at 25 degreeC is 3.5 or more. When the strong acidic substance with said pKa of less than 3.5 is used, the said pH at the time of melt | dissolving the PVA system polymer film obtained by the slight fluctuation | variation of the acidic substance usage in water may change greatly, and the target PVA system polymer film When it becomes difficult to obtain or when the dispersion | variation in the density | concentration of such a strong acidic substance in the PVA-type polymer film arises, there exists a possibility that a problem, such as yellowing, may arise in the site | part with high density | concentration.

Moreover, it is preferable that the boiling point in normal pressure (1 atm by absolute pressure) of an acidic substance (C) exceeds 120 degreeC. When the boiling point under normal pressure is 120 ° C. or less, the acidic substance is gradually volatilized from the PVA-based polymer film during long-term storage, and there is a concern that the inhibitory effect of yellowing is lowered. In addition, in this specification, it is assumed that an acidic substance does not have a volatile substantially at 120 degreeC under normal pressure, and the boiling point under normal pressure exceeds 120 degreeC. Here, as an acid substance which is not substantially volatile, for example, after reducing about 1 g of the said acid substance prescribed | regulated to the evaporating dish and holding this at 120 degreeC under normal pressure for 10 minutes, the amount of reduction of the said mass of acid substance is 10 mass Acidic substances etc. which are% or less are mentioned. As for the boiling point of an acidic substance (C), it is more preferable that it is 125 degreeC or more, and it is still more preferable that it is 130 degreeC or more.

As an acidic substance with the boiling point over 120 degreeC under normal pressure which pKa in 25 degreeC is 3.5 or more, For example, organic acids, such as lactic acid, succinic acid, adipic acid, benzoic acid, capric acid, citric acid, lauric acid; Inorganic acid substances such as boric acid, potassium dihydrogen phosphate and sodium dihydrogen phosphate; Although amino acids, such as aspartic acid and glutamic acid, etc. are mentioned, It is not necessarily limited to these. These acidic substances may be used individually by 1 type, or may use 2 or more types together. Among these, an inorganic acid substance is preferable at the point which can disregard the acid work by volatilization substantially.

The amount of the acidic substance (C) preferably used in the production process of the PVA-based polymer film of the present invention has a pH at 20 ° C. when the PVA-based polymer film finally obtained is dissolved in water at a concentration of 7% by mass. 8.0 is in the range. The content rate of the used acidic substance (C) in the PVA-based polymer film (however, in the form of a conjugated base, it is assumed that the same number of moles of acidic substance (C) as the conjugated base is contained) is used. Although it cannot determine in a word according to the kind of acidic substance (C) used, etc., the ratio which becomes 0.0001-0.05 mol with respect to 100 g of PVA-type polymers (A) is mentioned, for example.

The PVA polymer film of the present invention has a pH at 20 ° C. when dissolved in water at a concentration of 7% by mass as described above, but is in the range of 2.0 to 8.0, but the PVA of the present invention exhibits such a pH when dissolved in water. If the system polymer film further contains an antioxidant (D), the reason is not clear, but the inhibitory effect of yellowing can be continued for a longer period of time. Such an effect of the antioxidant (D) is hardly confirmed in the case of a PVA-based polymer film having a pH at 20 ° C when dissolved in water at a concentration of 7% by mass, out of the above range.

Although there is no restriction | limiting in particular in the kind of antioxidant (D), Organic-type antioxidants, such as a phenol type, a phosphite system, a thioester system, a benzotriazole system, and a hindered amine system, are illustrated as a preferable thing.

It is preferable that it is in the range of 0.01-3 mass% based on the mass of surfactant (B), and, as for the content rate of antioxidant (D) in the PVA-type polymer film of this invention, it is more preferable to exist in 0.05-1 mass% range. If the content is less than 0.01% by mass based on the mass of the surfactant (B), the inhibitory effect of yellowing may not be sustained over a longer period. If it exceeds 3% by mass, the antioxidant (D) will aggregate and There exists a possibility that it may show as a fault on a PVA system polymer film, and may damage an external appearance.

The PVA-based polymer film is rigid compared to other plastic films in a state that does not contain a plasticizer, and mechanical properties such as impact strength and process passability during secondary processing may be problematic. In order to prevent such a problem, it is preferable to contain a plasticizer (E) in the PVA-type polymer film of this invention. Preferred plasticizers include polyhydric alcohols, and specific examples thereof include ethylene glycol, glycerin, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol and trimethylolpropane. These plasticizers (E) may be used individually by 1 type, or may use 2 or more types together. Among these plasticizers, ethylene glycol or glycerin is preferable from the viewpoint of the effect of improving the stretchability when the PVA-based polymer film of the present invention is used by stretching. As content rate of the plasticizer (E) in a PVA-type polymer film, it is preferable to exist in the range of 1-30 mass parts with respect to 100 mass parts of PVA-type polymers contained in a PVA-type polymer film, and it is more preferable to exist in the range which is 3-25 mass parts. It is more preferable to exist in the range of 5-20 mass parts. When the said content rate is less than 1 mass part, the said problem tends to arise easily, and when it exceeds 30 mass parts, a film may become too flexible and handleability may fall.

The PVA-based polymer film of the present invention may consist of only the PVA-based polymer (A) and the surfactant (B), and the PVA-based polymer (A) and the surfactant (B) and the above-mentioned acidic substance (C) (but the conjugate base In the case of the present invention, the salt may contain a salt containing the conjugated base), an antioxidant (D), and a plasticizer (E), but the range does not impair the effects of the present invention if necessary. In PVA (A), surfactant (B), acidic material (C) (but if it is in the form of a conjugated base, contains salts containing the conjugated base), antioxidants (D) and plasticizers (E It may further contain other components other than). As such another component, moisture, a ultraviolet absorber, a lubricating agent, a coloring agent, a filler, a preservative, a preservative, a high molecular compound other than the above-mentioned component, etc. are mentioned, for example. However, PVA-based polymer films containing chelating agents typified by polycarboxylic acids and polyamines or chelating compounds in which metals are coordinated with them easily form gels during the manufacturing process, and depending on the application, the gels may be used for the quality of the final product. It is preferable that the PVA-type polymer film does not contain any of a chelating agent and a chelating compound from the point that it may reduce the.

PVA-based polymer (A), surfactant (B), acidic substance (C) (however, in the form of conjugated base, it contains a salt containing the conjugated base), antioxidant (D) and plasticizer ( It is preferable that the ratio of the total value of each mass of E) to the total mass of the PVA-type polymer film of this invention exists in the range of 60-100 mass%, It is more preferable to exist in the range of 80-100 mass%, 90-100 mass It is more preferable to exist in% range.

The PVA-based polymer film of the present invention has a surfactant (B) of 0.001 to 1 parts by mass (preferably 0.01 to 0.7 parts by mass, more preferably 100 parts by mass of the PVA-based polymer (A) and the PVA-based polymer (A)). Preferably, it can manufacture by forming a film forming undiluted | stock solution containing 0.05-0.5 mass part). As a specific example of the said film forming undiluted | stock solution, PVA system polymer solution (A) which melt | dissolves in a solvent, for example, contains surfactant (B) in the said ratio, and PVA system polymer of water-containing state (A ) (Which may further contain an organic solvent, etc.) is melted, and a melt containing the surfactant (B) in the above ratio.

As a specific method for producing a PVA-based polymer film, for example, the above-mentioned PVA-based polymer solution can be used for the casting film forming method, the wet film forming method (discharged into a poor solvent), the wet and dry film forming method, and the gel film forming method (PVA-based film forming method). After cooling and gelling the polymer solution once, the solvent is extracted and removed to obtain a PVA polymer film), or a combination thereof to obtain the melt using a method or an extruder or the like, which is extruded in a T die or the like. Arbitrary methods, such as the melt-extrusion film forming method to form into a film, can be employ | adopted. Among them, the cast film forming method and the melt extrusion film forming method are preferable in that a PVA-based polymer film having high transparency and less coloring can be obtained.

It is preferable that it is in the range of 50-90 mass%, and, as for the volatile matter concentration (concentration of volatile components, such as a solvent removed by volatilization and evaporation at the time of film forming, etc.) of said film forming undiluted | stock solution, it is more preferable to exist in the range of 55-80 mass%. When volatile matter concentration is less than 50 mass%, a viscosity may become high and film forming may become difficult. On the other hand, when volatile matter concentration exceeds 90 mass%, since the viscosity becomes low and the thickness uniformity of the film obtained is easily impaired, it is not preferable.

There is no restriction | limiting in particular in the preparation method of the said film forming undiluted | stock solution, For example, surfactant (B) and acidic substance (C), antioxidant (D), When melt-kneading a PVA-based polymer (A) in a water-containing state using a method of adding a plasticizer (E) and at least one of the other components described above, or by using an extruder, the surfactant (B) is further acidic as necessary. The method of melt-kneading together at least 1 sort (s) of a substance (C), antioxidant (D), a plasticizer (E), and the said other component is mentioned. Among these, in the case of producing a PVA polymer film by the flexible film forming method, the surfactant (B) and, if necessary, an acidic substance (C) and an antioxidant (D) are dissolved in the PVA polymer (A) in water. ), A plasticizer (E) and a method of adding at least one of the other components described above are preferred.

Moreover, when mix | blending surfactant (B) at the time of preparation of a film forming undiluted | stock solution, when it uses in the form of the mixture containing surfactant (B) mentioned above, it does not perform complicated purification work of surfactant (B), and It is not necessary to use a more expensive high-purity surfactant (B), and it is preferable at the point which can manufacture a film forming undiluted | stock solution easily and inexpensively. In addition, when the said film forming undiluted | stock solution is obtained using an acidic substance (C), pH at the time of melt | dissolving the PVA-type polymer film obtained by adjusting the compounding quantity at the time of compounding of an acidic substance (C) in water is easy. It is preferable at the point which can adjust to the said range.

There is no restriction | limiting in particular in the thickness of the PVA-type polymer film of this invention, It can set to an appropriate thickness according to a use. Specifically, in packaging material use, it is preferable to exist in the range of 5-500 micrometers as an average thickness, and when using it as a raw material of a polarizing film, it is preferable to exist in the range of 5-150 micrometers as an average thickness. In addition, the average thickness of the PVA-based polymer film may measure the thickness of any ten points (for example, any ten points on a straight line drawn in the width direction of the PVA-based polymer film), and may be required as their average value. have.

Moreover, this invention includes the storage method of the PVA-type polymer film which stores the above-mentioned PVA-type polymer film of this invention on the conditions of temperature 0-40 degreeC, and humidity 75% RH or less. Although the PVA-based polymer film of the present invention has a feature of less yellowing when stored for a long period of time as compared to a conventional PVA-based polymer film, it tends to yellow easily as the temperature at the time of storage tends to be stored at a temperature below 40 ° C. It is preferable. Moreover, when the temperature at the time of storage is too low, condensation will arise on the film surface when taken out for use at a storage place, and this may cause abnormality, such as blocking of a film, sagging, or the like. From this viewpoint, it is preferable that the temperature at the time of storage is 0 degreeC or more. Similarly, when storing on conditions exceeding 75% RH, there exists a possibility that abnormality, such as blocking of a film or sagging, may arise by moisture absorption of a PVA-type polymer film. Although there is no restriction | limiting in particular in the storage period at the time of storing a PVA-type polymer film, It is preferable that it is 1 week or more and less than 2 years, since yellowing may progress gradually when it is too long especially especially when stored under high temperature, and is 1 month. It is more preferable that it is more than 1.5 years, and it is still more preferable that it is 3 months or more and less than 1 year.

There is no restriction | limiting in particular in the use of the PVA-type polymer film of this invention, For example, Packaging materials; Raw materials for manufacturing optical films, such as a polarizing film and retardation film; Water-soluble films such as Londry bags; Although it can be used as a release film when manufacturing artificial marble, the PVA-based polymer film of the present invention is hardly yellow in color even when stored in a warehouse for a long time, and it is difficult to give a bad impression to consumers or users. Is preferably used as a raw material for producing a packaging material, a polarizing film or a retardation film. In addition, the PVA-based polymer film of the present invention containing the surfactant (B) in the above ratio and having a pH at 20 ° C when dissolved in water at a concentration of 7% by mass is in the above range for a long time (preferably Is at least 72 hours, more preferably at least 120 hours, even more preferably at least 180 hours), even when continuously produced, streaky defects (parallel to the flow direction of the film) which are presumed to originate from the aggregates of the surfactant (B) In the case that high quality is required for the final product such as a polarizing film or a retardation film in that the generation of defects due to fine irregularities of the film occurring continuously or intermittently) can be highly suppressed, It can be used preferably.

Example

EXAMPLES The present invention will be specifically described below by way of Examples, but the present invention is not limited to these Examples in any way.

In addition, each measuring method of the pH and yellowness (YI value) of the PVA film when it melt | dissolves in PVA film employ | adopted in the following example and the comparative example is shown below.

[Measurement of pH when Dissolving PVA Film in Water]

7 g of PVA films were put in 93 g of deionized water at room temperature, and heated to about 90 ° C. under stirring to completely dissolve the film. The resulting aqueous solution was cooled to 20 ° C., and a pH meter (“MP230” manufactured by METTLER TOLEDO) was prepared. The pH of the aqueous solution was measured using.

[Measurement of Yellowness (YI Value) of PVA Film]

Eight sheets of films serving as samples were laminated and measured using the color difference meter (Model "NF-902" manufactured by Nippon Denshoku Industries Co., Ltd.) as the value of all eight sheets.

Example 1

100 mass parts of chips of PVA (polyvinyl acetate saponification) of 99.9 mol% of saponification degree, a polymerization degree of 2400, and sodium acetate content were immersed in 2500 mass parts of 35 degreeC distilled water for 24 hours, and then centrifugal dehydration was carried out and PVA A functional chip was obtained. The sodium acetate content in the obtained PVA hydrous chip was 0.1 mass% with respect to PVA, and the volatile matter concentration in the PVA hydrous chip was 70 mass%.

To 333 parts by mass of the PVA hydrous chip (100 parts by mass in terms of dry PVA), a mixture containing 12 parts by mass of glycerin and a surfactant (diethanolamine containing 95% by weight of diethanolamide and further a diethanolamine Containing as an impurity The pH at 20 ° C. (measured by the same method as described above for the case of PVA film) when the mixture was dissolved in water at a concentration of 0.1% by mass, 0.3 parts by mass , 0.003 parts by mass of 4,4'-butylidenebis (6-t-butyl-3-methylphenol) (phenolic antioxidant) was added, and a 1 mol / L potassium dihydrogen phosphate aqueous solution was added to 100 g of PVA. The mixture was added at a ratio of 10 ml to the mixture, and mixed well to obtain a mixture, which was heated and melted by a twin screw extruder having a maximum temperature of 130 ° C. After cooling to 100 degreeC by the heat exchanger, the film was melt-extruded and dried on a 95 degreeC metal drum, and the PVA film of 1.2 m in film width and 60 micrometers in average thickness was obtained. Defects, such as stripes, were not seen in the obtained PVA film, and the external appearance was favorable. It was 6.0 when the pH when melt | dissolved in water using the obtained PVA film was measured by said method.

Moreover, it was 4.6 when the obtained PVA film was cut into A4 size, and the yellowness (YI value) in the initial state was measured by the method mentioned above. This PVA film was suspended and left to stand in the hot air dryer adjusted to 80 degreeC. And yellowness (YI value) of the film after 3 days, after 5 days, and after 10 days after standing was measured by the method mentioned above, and it was 7.6, 9.0, and 10.1, respectively. Therefore, yellowing degree (ΔYI), which is an increase amount from the initial value of yellowness (YI value), was calculated to be 3.0, 4.4, and 5.5, respectively.

Table 1 shows the results of the above various evaluations. Moreover, although the said film forming was performed continuously for 240 hours, generation | occurrence | production of a stripe-like defect was not confirmed.

[Example 2]

In Example 1, instead of adding 1 mol / L aqueous potassium dihydrogen phosphate solution at a rate of 10 ml relative to 100 g of PVA, 1 mol / L aqueous lactic acid solution is 5 ml with respect to 100 g of PVA. Except having added in the ratio, it carried out similarly to Example 1, and obtained the PVA film. Defects, such as stripes, were not seen in the obtained PVA film, and the external appearance was favorable.

Using the obtained PVA film, it carried out similarly to Example 1, and performed various measurement. The results are shown in Table 1.

[Example 3]

In Example 1, instead of adding 1 mol / L aqueous potassium dihydrogen phosphate solution at a rate of 10 ml relative to 100 g of PVA, 1 mol / L acetic acid aqueous solution is 10 ml with respect to 100 g of PVA. Except having added in the ratio, it carried out similarly to Example 1, and obtained the PVA film. Defects, such as stripes, were not seen in the obtained PVA film, and the external appearance was favorable.

Using the obtained PVA film, it carried out similarly to Example 1, and performed various measurement. The results are shown in Table 1.

Example 4

In Example 2, the PVA film was obtained like Example 2 except having changed the addition amount of the lactic acid aqueous solution into the ratio which becomes 2 ml with respect to 100 g of PVA in the ratio which becomes 5 ml with respect to 100 g of PVA. Defects, such as stripes, were not seen in the obtained PVA film, and the external appearance was favorable.

Using the obtained PVA film, it carried out similarly to Example 1, and performed various measurement. The results are shown in Table 1.

[Example 5]

As a chip of PVA, the chip | tip of PVA (saponified polyvinyl acetate) of the saponification degree 88.0 mol%, the polymerization degree 2400, and the sodium acetate content 2.0 mass% was used like Example 1, and the PVA hydrous chip was obtained. The sodium acetate content in the obtained PVA hydrous chip was 0.08 mass% with respect to PVA, and the volatile matter concentration in the PVA hydrous chip was 86 mass%. This PVA hydrous chip was dried under reduced pressure at 20 ° C, and the volatile matter concentration was adjusted to 70 mass%.

A PVA film was obtained in the same manner as in Example 1 except that the volatile matter concentration used in Example 1 was used in place of the 70 mass% PVA hydrous chip. Defects, such as stripes, were not seen in the obtained PVA film, and the external appearance was favorable.

Using the obtained PVA film, it carried out similarly to Example 1, and performed various measurement. The results are shown in Table 1.

[Example 6]

In Example 1, a PVA film was obtained in the same manner as in Example 1 except that 4,4'-butylidenebis (6-t-butyl-3-methylphenol) was not added. Defects, such as stripes, were not seen in the obtained PVA film, and the external appearance was favorable.

Using the obtained PVA film, it carried out similarly to Example 1, and performed various measurement. The results are shown in Table 1.

[Example 7]

In Example 1, the amount of 4,4'-butylidenebis (6-t-butyl-3-methylphenol) added was 0.003 parts by mass with respect to 333 parts by mass of the PVA hydrous chip (100 parts by mass in terms of dry PVA). A PVA film was obtained in the same manner as in Example 1 except that the content was changed to 0.018 parts by mass. Although it does not become practically impaired with the obtained PVA film, when it observes under strong light, such as daylight, the aggregate form estimated by 4, 4- butylidene bis (6-t- butyl- 3-methyl phenol) is estimated. The defects looked light.

Using the obtained PVA film, it carried out similarly to Example 1, and performed various measurement. The results are shown in Table 1.

[Example 8]

In Example 1, the PVA film was obtained like Example 1 except having changed the addition amount of the potassium dihydrogen phosphate aqueous solution into the ratio which becomes 5 ml with respect to 100 g of PVA in the ratio which becomes 10 ml with respect to 100 g of PVA. . Defects, such as stripes, were not seen in the obtained PVA film, and the external appearance was favorable.

Using the obtained PVA film, it carried out similarly to Example 1, and performed various measurement. The results are shown in Table 1. Moreover, when said film forming was performed continuously for 240 hours, generation | occurrence | production of the stripe | stain defect was confirmed slightly.

[Example 9]

In Example 8, a PVA film was obtained in the same manner as in Example 8 except that 4,4'-butylidenebis (6-t-butyl-3-methylphenol) was not added. Defects, such as stripes, were not seen in the obtained PVA film, and the external appearance was favorable.

Using the obtained PVA film, it carried out similarly to Example 1, and performed various measurement. The results are shown in Table 1.

Comparative Example 1

Example 1 was carried out except that none of glycerin, a mixture containing a surfactant, 4,4'-butylidenebis (6-t-butyl-3-methylphenol), and an aqueous solution of potassium dihydrogen phosphate was added. A PVA film was obtained in the same manner as in Example 1. The obtained PVA film had many defects, such as a stripe, and was bad in appearance.

Using the obtained PVA film, it carried out similarly to Example 1, and performed various measurement. The results are shown in Table 1.

Comparative Example 2

In Example 1, a PVA film was prepared in the same manner as in Example 1 except that none of 4,4'-butylidenebis (6-t-butyl-3-methylphenol) and potassium dihydrogen phosphate solution was added. Got it. Defects, such as stripes, were not seen in the obtained PVA film, and the external appearance was favorable.

Using the obtained PVA film, it carried out similarly to Example 1, and performed various measurement. The results are shown in Table 1.

[Comparative Example 3]

In Example 1, the PVA film was obtained like Example 1 except not having added the potassium dihydrogen phosphate aqueous solution. Defects, such as stripes, were not seen in the obtained PVA film, and the external appearance was favorable.

Using the obtained PVA film, it carried out similarly to Example 1, and performed various measurement. The results are shown in Table 1. Moreover, as a result of performing said film forming for 240 hours continuous, generation | occurrence | production of the stripe | stain defect was confirmed.

[Comparative Example 4]

In Example 2, instead of adding 1 mol / L lactic acid aqueous solution at a ratio of 5 ml to 100 g of PVA, lactic acid was used as it is without dilution in water, and 0.1 mol was added to 100 g of PVA. A mixture of the PVA hydrous chip and various additives was obtained in the same manner as in Example 1 except that the amount was added in the proportion of 1 wt. The aqueous solution of 7 mass% of solid content concentration was manufactured by adding water to this mixture. It was 1.7 when the pH of the obtained aqueous solution was measured by the method similar to the above regarding the case of PVA film. When this mixture was melt-formed using an extruder, the film formation was abandoned because there is a possibility that the plating applied to the molten resin flow path may corrode.

[Comparative Example 5]

In Example 1, except that the addition amount of the mixture containing surfactant was changed from 0.3 mass part to 3 mass parts with respect to 333 mass parts of PVA hydrous chips (100 mass parts in dry state PVA conversion), and it carried out similarly to Example 1 A PVA film was obtained. The obtained PVA film had many defects, such as a stripe, and was bad in appearance.

Using the obtained PVA film, it carried out similarly to Example 1, and performed various measurement. The results are shown in Table 1.

[Example 10]

The PVA film obtained in Example 1 was wound 50 m in roll shape in the paper tube of 3 inches in diameter, and was stored in the thermo-hygrostat adjusted to the temperature of 30 degreeC, and 50% RH of humidity. 6 months later, the yellowness (YI value) of the PVA film was measured by the above-mentioned method. As a result, it was 5.4 with respect to 4.6 before storage start, and yellowing degree ((DELTA) YI) was small as 0.8. Moreover, the membrane surface was favorable without change in particular before storage. The evaluation results are shown in Table 2.

[Comparative Example 6]

In Example 10, the PVA film was stored like Example 10 except having used the PVA film obtained in Comparative Example 3 instead of using the PVA film obtained in Example 1. Table 2 shows the evaluation results of the PVA film taken out after 6 months.

Industrial availability

According to the present invention, the PVA-based polymer film can be obtained, for example, from a packaging material, in that it is possible to obtain a PVA-based polymer film in which the color of the film is less likely to be yellow even after long-term storage in a warehouse or the like. Raw materials for manufacturing optical films, such as a polarizing film and retardation film; Water-soluble films such as Londry bags; It can use suitably as a release film at the time of manufacturing an artificial marble.

Claims (11)

A polyvinyl alcohol polymer film containing 0.001 to 1 parts by mass of a surfactant (B) based on 100 parts by mass of the polyvinyl alcohol polymer (A) and the polyvinyl alcohol polymer (A), and 7% by mass in water The polyvinyl alcohol polymer film whose pH at 20 degreeC when melt | dissolving at the density | concentration of is 2.0-8.0. The method of claim 1,
The polyvinyl alcohol polymer film whose saponification degree of a polyvinyl alcohol polymer (A) is 90 mol% or more. 3. The method according to claim 1 or 2,
The polyvinyl alcohol polymer film obtained using an acidic substance (C). The method of claim 3, wherein
The polyvinyl alcohol polymer film whose pKa (acid dissociation constant) at 25 degrees C of an acidic substance (C) is 3.5 or more, and whose boiling point under normal pressure of the said acidic substance (C) exceeds 120 degreeC. The method according to any one of claims 1 to 4,
The polyvinyl alcohol polymer film whose surfactant (B) is a nonionic surfactant. The method of claim 5, wherein
The polyvinyl alcohol polymer film whose nonionic surfactant is an alkanolamide-type surfactant. 7. The method according to any one of claims 1 to 6,
The polyvinyl alcohol polymer film containing 0.01-3 mass% of antioxidant (D) with respect to surfactant (B). A process for preparing a film forming undiluted solution containing 0.001 to 1 parts by mass of the surfactant (B) with respect to 100 parts by mass of the polyvinyl alcohol polymer (A) and the polyvinyl alcohol polymer (A), and the film forming undiluted solution The manufacturing process of the polyvinyl alcohol polymer film of any one of Claims 1-7 with which the said film forming undiluted | stock solution is obtained using the mixture containing 70 mass% or more of surfactants (B). Way. The method of claim 8,
The said film forming undiluted | stock solution is obtained using an acidic substance (C). 10. The method according to claim 8 or 9,
The pH at 20 degreeC when the said mixture melt | dissolves in the density | concentration of 0.1 mass% in water becomes 8.0 or more. The polyvinyl alcohol polymer film as described in any one of Claims 1-7 is stored under the conditions of the temperature of 0-40 degreeC, and humidity of 75% RH or less, The storage method of the polyvinyl alcohol polymer film characterized by the above-mentioned.