JP2000309607A - Vinyl alcohol polymer and composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vinyl alcohol polymer and composition excellent in stability, water resistance, gas barrier property, water vapor barrier property, low-temperature storage stability of an aqueous solution and biodegradability. SOLUTION: The content of an ethylene unit is 2 to 19 mol%,
A vinyl alcohol polymer having a degree of polymerization of 200 to 2000, a degree of saponification of 80 to 99.99 mol%, and a total content of carboxyl groups and lactone rings of 0.02 to 0.4 mol%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a vinyl alcohol polymer and a composition thereof. More specifically, the present invention relates to a vinyl alcohol-based polymer having good thermal stability, water resistance, gas barrier properties, water vapor barrier properties, low-temperature storage stability of an aqueous solution, and biodegradability, and a composition thereof.

[0002]

2. Description of the Related Art Conventionally, polyvinyl alcohol (hereinafter referred to as P
VA) is one of the few crystalline water-soluble polymers having excellent film-forming properties, transparency, strength properties and surface activity. Paper modifying agents, paper, wood and inorganic adhesives, warp sizing agents, stabilizers for emulsion polymerization and suspension polymerization,
It is widely used for various binders and the like, and occupies an important position as a raw material for polyvinyl alcohol-based films, polyvinyl alcohol-based fibers, and polyvinyl alcohol-based sheets. As the conventional PVA, “completely saponified PVA” having a saponification degree of about 98 mol% and “partially saponified PVA” having a saponification degree of about 88 mol% are known. On the other hand, the pursuit of high functionality by introducing a functional group to improve specific performance has also been pursued, and various so-called modified polyvinyl alcohols have been developed.

[0003] Conventional PVA has been used in the form of an aqueous solution because of a problem in thermal stability. That is, in the case of “fully saponified PVA”, the melting point and the thermal decomposition temperature were very close, and hot melt molding was impossible. On the other hand, in the case of "partially saponified PVA" having a melting point lower than that of "completely saponified PVA", there is a problem that acetic acid odor is generated during hot melt molding due to poor thermal stability. Next, a method has been proposed in which a melt viscosity of PVA is reduced by blending a plasticizer or another polymer with PVA, and PVA is hot-melt molded. However, in the method of adding a plasticizer, when the molded article is used for a long period of time, the plasticizer content in the molded article decreases with time, and the molded article becomes soft under low temperature and low humidity such as in winter. There is a problem that the molded product is cracked or cracked due to insufficient properties. On the other hand, the method of blending PVA with another polymer has a problem that the mechanical properties of the molded product are significantly reduced and the transparency is significantly reduced due to poor compatibility between the two.

Next, by modifying PVA, PVA is modified.
A method for lowering the melting point of A has been proposed. However, PVA having an ω-hydroxyalkyl vinyl ether unit and an alkyl vinyl ether unit (Japanese Patent Publication No.
No. 10885) and PVA having a polyoxyethylene monoallyl ether unit (Japanese Examined Patent Publication No. 5-49683) have a problem that thermal stability is low because they have an ether bond. Further, PVA having an allyl alcohol unit (Japanese Patent Application Laid-Open No. Sho 62-229135) has a somewhat improved thermal stability, but is still insufficient for practical use, and the allyl alcohol remaining in PVA is There was a problem with safety. PV having α-olefin unit
A (Japanese Patent Application Laid-Open No. 63-289581) has a problem that the melt viscosity is remarkably increased due to association of a hydrophobic group and that it is insoluble in water. Further, PVA having a hydroxyalkyl group having a specific number of carbon atoms in a side chain (JP-A-7-2286)
No. 25) has a somewhat improved thermal stability, but is still insufficient for practical use.

[0005] Further, PVA has the advantages of being excellent in gas barrier properties and transparency and having few problems in terms of disposal.
A film using “fully saponified PVA” may be used as a gas barrier layer. However, it is known that the PVA film has a high gas barrier property when the amount of moisture absorption is small, that is, in a dry atmosphere, but when the relative humidity is about 70% or more, the moisture absorption property is so strong that the gas barrier property tends to decrease. As a method of reducing the hygroscopicity of PVA, a method of using an ethylene / vinyl alcohol copolymer (hereinafter abbreviated as EVOH) obtained by copolymerizing ethylene in an amount of 20 mol% or more has been adopted. However, EVOH is insoluble in water. There is a problem that when using a solution, an organic solvent is used, so that the working environment is significantly deteriorated. In addition, a modified PVA having a crosslinking property may be used, or PVA may be used.
A method has been proposed to introduce a crosslinked structure by reacting the compound with a coupling agent or with another polymer, but the gas barrier property under high humidity is still inadequate due to the formation of voids due to the crosslinking. It is enough.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a vinyl alcohol-based resin which simultaneously solves the problems of the conventional PVA, such as thermal stability, water resistance, gas barrier property, water vapor barrier property, and low-temperature storage stability of an aqueous solution. It is to provide a polymer. Furthermore, the object of the present invention is thermal stability, water resistance,
An object of the present invention is to provide a vinyl alcohol-based polymer composition having excellent gas and water vapor barrier properties, low-temperature storage stability of an aqueous solution, and excellent biodegradability.

[0007]

Means for Solving the Problems The present inventors have conducted intensive studies to develop a vinyl alcohol-based polymer having the above-mentioned preferable properties.
19 mol%, polymerization degree 200-2000, saponification degree 80-
A vinyl alcohol polymer having a content of 99.99 mol% and a total content of carboxyl groups and lactone rings of 0.02 to 0.4 mol% was found, and the present invention was completed.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS It is essential that the vinyl alcohol-based polymer of the present invention has an ethylene unit. The content of the ethylene unit is essential to be 2 to 19 mol%, preferably 2.5 to 17 mol%, and more preferably 3 to 19 mol%.
15 mol% is more preferable, and 3.5 to 13 mol% is particularly preferable. When the content of the ethylene unit is less than 2 mol%, the degree of improvement in the above-mentioned thermal stability, water resistance, gas barrier property, water vapor barrier property, stability of the aqueous solution at low temperature storage and biodegradability is small. When the content of the ethylene unit is more than 19 mol%, the water solubility which is the most characteristic feature of PVA is reduced.

The ethylene unit content of the vinyl alcohol polymer of the present invention was determined by proton NMR of a polyvinyl ester containing an ethylene unit, which is a precursor of the vinyl alcohol polymer. That is, the obtained polyvinyl ester was sufficiently purified by reprecipitation with n-hexane / acetone three times or more, and then dried under reduced pressure at 80 ° C. for 3 days to prepare a polyvinyl ester for analysis. The polymer was dissolved in DMSO-D ₆ and measured at 80 ° C. using 500 MHz proton NMR (JEOL GX-500). A peak derived from the main chain methine of the vinyl ester (4.7 to 5.2 ppm) and a peak derived from ethylene, the vinyl ester and the main chain methylene of the third component (0.
(8 to 1.6 ppm) to calculate the content of ethylene units.

The vinyl alcohol polymer of the present invention has a viscosity average degree of polymerization (hereinafter abbreviated as polymerization degree) of 200 to 20.
00, preferably 220-1800, and 240-1
600 is more preferable, and 250 to 1500 is particularly preferable. When the degree of polymerization is less than 200, a molded product obtained,
Not only does workability in the production of fibers, films, etc. deteriorate, and satisfactory products cannot be obtained, but also the obtained products have low mechanical strength, and the characteristics of PVA are impaired. Polymerization degree 2
If it exceeds 000, the melt viscosity at the time of melt molding and the aqueous solution viscosity at the time of aqueous solution processing become high, and workability and processability deteriorate, and at the same time, satisfactory products cannot be obtained. The degree of polymerization (P) of the PVA-based polymer is measured according to JIS-K6726. That is, after the PVA-based polymer is re-saponified and purified, the intrinsic viscosity [η] (d) measured in water at 30 ° C.
1 / g) according to the following equation. P = ([η] × 10 ³ /8.29) ^{(1 / 0.62)}

The degree of saponification of the vinyl alcohol polymer of the present invention is from 80 to 99.99 mol%, and from 84 to 99.9.
Mol% is preferable, 87 to 99.7 mol% is more preferable, and 90 to 99.5 mol% is particularly preferable. When the degree of saponification is less than 80 mol%, the crystallinity of the vinyl alcohol-based polymer is extremely lowered, and not only the high gas barrier properties, water vapor barrier properties and water resistance intended by the present invention are not obtained,
Because of poor thermal stability, satisfactory melting and spinning cannot be performed due to thermal decomposition and gelation. On the other hand, the degree of saponification is 9
A vinyl alcohol polymer having a content of more than 9.99 mol% cannot be produced stably, and molding, film formation and fiberization cannot be stabilized.

The total content of carboxyl groups and lactone rings of the vinyl alcohol polymer of the present invention is 0.02 to 0.5.
4 mol%, preferably 0.022 to 0.37 mol%, more preferably 0.024 to 0.33 mol%,
025 to 0.3 mol% is particularly preferred. The carboxyl group in the present invention includes an alkali metal salt thereof, and examples of the alkali metal include potassium and sodium. The total content of carboxyl groups and lactone rings is 0.0
When the amount is less than 2 mol%, the thermal stability is poor and the melt formability and melt spinnability are reduced due to gelation, and the viscosity stability of the aqueous solution at a low temperature and the viscosity stability of the highly concentrated aqueous solution are reduced. Does not become the intended vinyl alcohol polymer.
On the other hand, when the total content of the carboxyl group and the lactone ring is 0.1.
If it exceeds 40 mol%, it is presumed that the thermal stability of PVA at the time of melting is poor, so that it cannot be melt-spun or melt-molded due to thermal decomposition and gelation, and that the affinity with water increases. The barrier properties and water resistance of gas and water vapor may be reduced, and the biodegradability may be reduced.

Further, it has been found that when the total content of the carboxyl group and the lactone ring satisfies the following expression 3, the effect of the present invention is significantly increased.

[0014]

(Equation 3)

Here, the content (unit: mol%) represents the total content of the carboxyl group and the lactone ring, and P represents the viscosity average degree of polymerization of the vinyl alcohol polymer. ｝

As a method for producing a vinyl alcohol-based polymer having a specific amount of ethylene units and having a carboxyl group and a lactone ring, a vinyl ester-based monomer such as vinyl acetate has a capability of forming a carboxyl group and a lactone ring. A method of saponifying a vinyl ester polymer obtained by copolymerizing a monomer with an alcohol or dimethyl sulfoxide solution, mercaptoacetic acid,
In the presence of a thiol compound containing a carboxyl group such as mercaptopropionic acid, a method of polymerizing a vinyl ester monomer and then saponifying it, when polymerizing a vinyl ester monomer such as vinyl acetate, A method of causing a chain transfer reaction of an ester monomer and a vinyl ester polymer to an alkyl group to obtain a highly branched vinyl ester polymer followed by saponification, a monomer having an epoxy group and a vinyl ester monomer A saponification reaction after reacting a copolymer with a thiol compound having a carboxyl group, and a method by acetalization reaction of PVA with an aldehyde having a carboxyl group.

The vinyl ester monomers include vinyl formate, vinyl acetate, vinyl propionate, vinyl valerate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl benzoate, vinyl pivalate and vinyl versatate. Among these, vinyl acetate is preferred from the viewpoint of obtaining PVA. Examples of the monomer having an ability to form a carboxyl group and a lactone ring of the present invention include a monomer having a carboxyl group derived from fumaric acid, maleic acid, itaconic acid, maleic anhydride or itaconic anhydride, acrylic acid And its salts, methyl acrylate, ethyl acrylate, n-propyl acrylate, acrylates such as i-propyl acrylate, methacrylic acid and its salts, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, Methacrylic esters such as i-propyl methacrylate, acrylamide, N-methylacrylamide, N
Acrylamide derivatives such as -ethylacrylamide, and methacrylamide derivatives such as methacrylamide, N-methylmethacrylamide and N-ethylmethacrylamide.

The total content of carboxyl groups and lactone rings of the vinyl alcohol polymer can be determined from the peak of proton NMR. After completely saponifying the vinyl alcohol-based polymer to a degree of saponification of 99.95 mol% or more, it was thoroughly washed with methanol, and then dried at 90 ° C. under reduced pressure for 2 days to prepare a vinyl alcohol-based polymer for analysis.
In the above case, to dissolve the polyvinyl alcohol for analysis created DMSO-D _6, measured at 60 ° C. using a 500MHz proton NMR (JEOL GX-500). Monomers of acrylic acid, acrylates, acrylamide and acrylamide derivatives were obtained by using a peak (2.0 ppm) derived from the main chain methine to form methacrylic acid, methacrylic esters, methacrylamide and methacrylamide derivatives. The dimer has a peak (0.6 to 1.1 pp) derived from a methyl group directly connected to the main chain.
Using m), the content was calculated by an ordinary method. Fumaric acid, maleic acid, itaconic acid, monomers having a carboxyl group derived from maleic anhydride or itaconic anhydride and the like, in addition a few drops of lysis after trifluoroacetic acid PVA for analysis created DMSO-D _6, It measured at 60 degreeC using 500 MHz proton NMR (JEOLX-500). For quantification, the content was calculated by a conventional method using a methine peak of a lactone ring assigned to 4.6 to 5.2 ppm. In the cases of and, the content was calculated using the peak (2.8 ppm) derived from methylene bonded to the sulfur atom. In the case of, the prepared analytical PVA is
It was dissolved in D ₄ / D ₂ O = 2/8 and measured at 80 ° C. using 500 MHz proton NMR (JEOL GX-500). The peak derived from the methylene of the terminal carboxyl group or an alkali metal salt thereof (the following chemical formulas 1 and 2) belongs to 2.2 ppm (integral value A) and 2.3 ppm (integral value B). The peak derived from (the following chemical formula 3) is 2.6 ppm (integral value C), and the peak derived from methine in the vinyl alcohol unit is 3.5 to 4.15.
ppm (integral value D), and the content of a carboxyl group and a lactone ring is calculated by the following chemical formula 3. Here, △ indicates the amount of modification (mol%). Content of carboxyl group and lactone ring (mol%) =
50 × (A + B + C) × (100− △) / (100 ×
D)

[0019]

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[0020]

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[0021]

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In the case of (1), the prepared analysis PVA is
It was dissolved in O-D ₆ and proton NMR at 500 MHz (J
EOL GX-500) at 60 ° C. Peak 4.8 to 5.2 derived from methine in the acetal moiety
The content was calculated by a standard method using ppm (the following chemical formula 4).

[0023]

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As long as the effects of the present invention are not impaired,
It may contain a monomer unit other than a vinyl alcohol unit, an ethylene, a vinyl ester unit and a monomer having the ability to form a carboxyl group and a lactone ring described above. Examples of such a unit include α-olefins such as propylene, 1-butene, isobutene and 1-hexene, methyl vinyl ether, ethyl vinyl ether, n
Vinyl ethers such as -propyl vinyl ether, i-propyl vinyl ether, n-butyl vinyl ether,
Hydroxy group-containing vinyl ethers such as ethylene glycol vinyl ether, 1,3-propanediol vinyl ether, and 1,4-butanediol vinyl ether;
Allyl acetate, propyl allyl ether, butyl allyl ether, allyl ethers such as hexyl allyl ether, monomers having an oxyalkylene group, vinylsilanes such as vinyltrimethoxysilane, isopropenyl acetate, 3-buten-1-ol, 4-penten-1-ol, 5-hexen-1-ol, 7-octen-1-
Hydroxy-containing α-olefins such as all, 9-decene-1-ol, 3-methyl-3-buten-1-ol, ethylenesulfonic acid, allylsulfonic acid, methallylsulfonic acid, 2-acrylamide-2 A monomer having a sulfonic acid group derived from methylpropanesulfonic acid or the like; vinyloxyethyltrimethylammonium chloride, vinyloxybutyltrimethylammonium chloride, vinyloxyethyldimethylamine, vinyloxymethyldiethylamine, N-acrylamidomethyltrimethylammonium chloride , 3- (N-methacrylamido) propyltrimethylammonium chloride, N-
Monomers having a cationic group derived from acrylamidoethyltrimethylammonium chloride, N-acrylamidodimethylamine, allyltrimethylammonium chloride, methallyltrimethylammonium chloride, dimethylallylamine, allylethylamine and the like can be mentioned. The content of these monomers varies depending on the purpose and use of the monomers, but is usually 20 mol% or less, preferably 10 mol% or less.

The vinyl alcohol-based polymer of the present invention can be used in the presence of a vinyl ester monomer such as vinyl acetate in the presence of a thiol compound such as 2-mercaptoethanol or n-dodecyl mercaptan except for the mercaptan having a carboxyl group. May be terminally modified by copolymerizing with ethylene and saponifying it.

Examples of the method for copolymerizing the vinyl ester monomer with ethylene include known methods such as bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization. Among them, a bulk polymerization method or a solution polymerization method in which polymerization is performed without a solvent or in a solvent such as an alcohol is usually employed. Examples of the alcohol used as a solvent during the solution polymerization include lower alcohols such as methyl alcohol, ethyl alcohol, and propyl alcohol. Examples of the initiator used for the copolymerization include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethyl-valeronitrile), benzoyl peroxide, and n-propylperoxydioxy. Known initiators such as azo initiators such as carbonates and peroxide initiators are exemplified. The polymerization temperature is not particularly limited, but is suitably in the range of 0 ° C to 150 ° C. However, in selecting the polymerization conditions, it is necessary to appropriately set various conditions so that the vinyl alcohol-based polymer aimed at by the present invention is obtained, as is clear from the examples described later. .

The melting point of the vinyl alcohol polymer of the present invention is preferably from 160 to 230 ° C.
170-227 degreeC is preferable, 175-224 degreeC is more preferable, 180-220 degreeC is especially preferable. Melting point is 1
If the temperature is lower than 60 ° C., the crystallinity of the vinyl alcohol-based polymer is reduced, and the water resistance and the barrier properties against gas and water vapor are reduced, and satisfactory molded products and fibers having sufficient strength cannot be obtained. If the melting point exceeds 230 ° C., the melting temperature becomes high, and it becomes impossible to stably produce molded articles and fibers.

The melting point of the vinyl alcohol polymer is DS
Using C, in nitrogen, the temperature was raised to 250 ° C. at a rate of 10 ° C./min, and then cooled to room temperature.
It means the temperature at the peak top of the endothermic peak indicating the melting point of the vinyl alcohol polymer when the temperature is raised to 50 ° C.

The vinyl alcohol-based polymer of the present invention has biodegradability, and is decomposed into water and carbon dioxide when treated with activated sludge or buried in soil. When the PVA is continuously treated with activated sludge, it is completely decomposed in two days. From the viewpoint of biodegradability, the vinyl alcohol-based polymer needs to be water-soluble or water-dispersible, and the 1,2-glycol bond content of the vinyl alcohol-based polymer is 1.2 to 2 mol. %, More preferably 1.%.
25 to 1.95 mol% is preferable, and 1.3 to 1.9 mol% is more preferable. 1, of the vinyl alcohol-based polymer
When the 2-glycol bond content is less than 1.2 mol%, not only the biodegradability of the vinyl alcohol polymer described above is deteriorated, but also the melt viscosity is too high, and the moldability and spinnability are reduced. May be. If the 1,2-glycol bond content of the PVA exceeds 2 mol%, the barrier properties of gas and water vapor and the water resistance are lowered probably because the crystallinity of the PVA is lowered.

The 1,2-glycol bond content of the vinyl alcohol-based polymer can be controlled, for example, by the copolymerization represented by ethylene carbonate and the polymerization temperature. The 1,2-glycol bond content of PVA can be determined from the NMR peak. After saponification to a degree of saponification of 99.9 mol% or more, PVA was thoroughly washed with methanol, and dried at 90 ° C. under reduced pressure for 2 days.
The DMSO-D was dissolved in _6, a few drops added sample was trifluoroacetic acid 500MHz proton NMR (JEOL
GX-500) at 80 ° C. The peak derived from methine in the vinyl alcohol unit is 3.2 to 4.0 ppm.
(Integral value A ′), a peak derived from one methine of 1,2-glycol bond is assigned to 3.25 ppm (integral value B ′), and the 1,2-glycol bond content can be calculated by the following equation. Here, △ represents the ethylene modification amount (mol%). 1,2-glycol bond content (mol%) = B ′ (10
0- △) / A '

In the present invention, the central hydroxyl group of three hydroxyl groups in triad notation with respect to a vinyl alcohol unit is defined as 500 M of PVA in a DMSO-D ₆ solution.
Hz proton NMR (JEOL GX-500) device,
The peak (I) reflecting the tacticity of the triad of the hydroxyl proton measured at 65 ° C. is meant. Also,
The central hydroxyl group of three hydroxyl groups means a hydroxyl group of a central vinyl alcohol unit of three vinyl alcohol units. Peak (I) is the isotacticity chain (4.54 ppm) of the triad representation of the hydroxyl group of PVA,
The peak (II) derived from the hydroxyl group in all vinyl alcohol units is represented by the sum of the heterotacticity chain (4.36 ppm) and the syndiotacticity chain (4.13 ppm), and the chemical shift is 4.05 ppm.
From 4.70 ppm, the molar fraction of the center hydroxyl group of three hydroxyl groups in the triad display with respect to the vinyl alcohol unit of the present invention is 100 ×
(I) / (II).

In the present invention, by controlling the amount of the central hydroxyl group of the three hydroxyl groups, various physical properties relating to water, such as water solubility, moisture absorption, water resistance and barrier properties, strength and elongation of the vinyl alcohol polymer are obtained. It was found that various properties related to the fiber such as elastic modulus, melting point, melt viscosity, melt viscosity, etc. can be controlled. This is presumably because the central hydroxyl group of three hydroxyl groups in triad notation is rich in crystallinity and expresses the characteristics of the vinyl alcohol polymer.

The content of the 3-hydroxyl center hydroxyl group of the vinyl alcohol polymer of the present invention is preferably 65 to 98 mol%, and more preferably 7 to 98 mol%.
0 to 97.5 mol% is preferable, 72 to 97 mol% is more preferable, 74 to 96 mol% is further preferable, and
-95 mol% is particularly preferred. When the content of the central hydroxyl group of three hydroxyl groups in a triad display of PVA is less than 65 mol%, the crystallinity of the vinyl alcohol polymer is extremely reduced, and the high gas and water vapor barrier intended by the present invention is intended. In addition to being unable to obtain water resistance and water resistance, it is not possible to perform satisfactory melt molding and melt spinning due to poor thermal stability and thermal decomposition and gelation. Further, in the obtained films, molded products, fibers, and the like, the mechanical properties and the like, which are features of the vinyl alcohol-based polymer, are impaired. On the other hand, the PV
When the content of the central hydroxyl group of three hydroxyl groups in the triad notation of A is more than 98 mol%, the crystallinity of the polymer is extremely high, and it takes a great effort to prepare an aqueous solution of PVA, or the melting point is lowered. Due to the high temperature, the melt molding temperature needs to be increased, and as a result, the thermal stability during polymer melt molding is poor, and the polymer is largely decomposed and gelled, and the polymer coloring and gelling are large.

Further, when the vinyl alcohol polymer of the present invention has a mole fraction of three hydroxyl groups in the center of triads with respect to a vinyl alcohol unit satisfying the following formula 4, the effect of the present invention is remarkably high. I found out.

[0035]

(Equation 4)

Here, the mole fraction (unit: mole%) represents the mole fraction of the center hydroxyl group of three hydroxyl groups in triad notation with respect to the vinyl alcohol unit, and Et is the ethylene content (containing the vinyl alcohol polymer). (Unit: mol%). ｝

The vinyl alcohol polymer composition containing ethylene of the present invention is characterized by having an alkali metal. The content ratio of the alkali metal (B) to 100 parts by weight of the vinyl alcohol-based polymer (A) is such that the alkali metal (B) is 0.0003 to 1 part by weight in terms of sodium, and 0.0003 to 0.8 part by weight. Is preferred,
0.0005 to 0.6 parts by weight is more preferable,
Particularly preferred is 0.5 to 0.5 part by weight. Examples of the alkali metal include potassium, sodium and the like. These are mainly salts of lower fatty acids such as acetic acid and propionic acid, salts of carboxyl groups of PVA containing a specific amount of carboxyl groups and copolymer monomers of the present invention. It may be present as a salt of sulfonic acid contained in the compound, or may be present in the additive. Alkali metal content of 0.0
When the amount is less than 003 parts by weight, when the vinyl alcohol-based polymer is used as an aqueous solution, the water solubility of the PVA decreases, and satisfactory characteristics are not exhibited. In addition, when a vinyl alcohol polymer is used for melting, not only the gelation during the melting of PVA is large and the melt moldability and melt spinnability are reduced, but also the productivity is reduced, and the obtained molded articles and fibers are also reduced. Does not have sufficient water solubility. On the other hand, when the content of the alkali metal is more than 1 part by weight, the thermal stability at the time of melting is poor, and decomposition, gelation, and polymer coloring are remarkable, and molding and fiberization cannot be performed. In addition, the barrier property of gas or water vapor is lowered probably because the crystallinity of the vinyl alcohol polymer is lowered.

In the present invention, the method of incorporating a specific amount of the alkali metal (B) into the vinyl alcohol-based polymer is not particularly limited, and once the vinyl alcohol-based polymer is obtained, the alkali metal-containing compound is added. Method,
When saponifying a vinyl ester polymer in a solvent, an alkali metal containing an alkali metal is used as a saponification catalyst to blend the alkali metal into the vinyl alcohol polymer, and the saponified vinyl alcohol-based polymer is obtained. By washing the polymer with a washing solution,
A method of controlling the alkali metal contained in the vinyl alcohol-based polymer may be mentioned, but the latter is more preferable. The content of the alkali metal can be determined by an atomic absorption method.

The process for producing the specific ethylene-containing vinyl alcohol polymer of the present invention is as follows. Known methods such as a method of saponification in a sulfoxide solution can be used.

The alkaline substance used as the saponification catalyst includes potassium hydroxide or sodium hydroxide. The molar ratio of the alkaline substance used in the saponification catalyst is preferably from 0.004 to 0.5, more preferably from 0.005 to 0.05, based on the vinyl acetate unit. The saponification catalyst may be added all at once in the early stage of the saponification reaction, or may be added during the saponification reaction. Examples of the solvent for the saponification reaction include methanol, methyl acetate, dimethyl sulfoxide, dimethylformamide and the like. Of these solvents, methanol is preferred, and the water content is 0.1%.
Methanol controlled at 001 to 1% by weight is more preferable, methanol controlled at a water content of 0.003 to 0.9% by weight is more preferable, and methanol controlled at a water content of 0.005 to 0.8% by weight is preferable. Particularly preferred. The temperature of the saponification reaction is preferably 5 to 80 ° C, more preferably 20 to 70 ° C.
Is more preferred. The saponification time is preferably 5 minutes to 10 hours, more preferably 10 minutes to 5 hours. Known methods such as a batch method and a continuous method can be applied as the saponification method.

As the cleaning solution, methanol, acetone,
Examples thereof include methyl acetate, ethyl acetate, hexane, and water, and among them, methanol, methyl acetate, and water alone or a mixed solution are more preferable. The amount of the cleaning liquid is set so as to satisfy the content ratio of the alkali metal (B), but usually, 30 to 10 parts by weight based on 100 parts by weight of PVA.
000 parts by weight is preferable, and 50 to 3000 parts by weight is more preferable. The washing temperature is preferably from 5 to 80C,
20-70 degreeC is more preferable. The washing time is preferably from 20 minutes to 10 hours, more preferably from 1 hour to 6 hours. Known methods such as a batch method and a countercurrent cleaning method can be applied as the cleaning method. As is clear from Examples 1 to 29 described below, the vinyl alcohol-based copolymer and composition of the present invention were prepared under the polymerization conditions (polymerization temperature, vinyl acetate, solvent, ethylene addition amount, ethylene, By selecting the addition conditions, polymerization ethylene pressure, polymerization time, polymerization rate, delay addition conditions such as maleic anhydride) and saponification conditions (polyvinyl acetate concentration, alkali amount, temperature, time, neutralization treatment, washing treatment) can get. Unless appropriate conditions are selected, the intended vinyl alcohol-based polymer and composition cannot be obtained as is apparent from Comparative Examples 1 to 25.

The specific ethylene modification amount, polymerization degree,
Degree of saponification, carboxyl group and lactone ring amount, 1,2
-The composition containing a vinyl alcohol polymer having a glycol bond amount, a hydroxyl group, and a specific alkali metal has remarkably excellent thermal stability as compared with conventional PVA, and is melt-formed or melt-spun. It is useful as a resin for applications. That is, the vinyl alcohol-based polymer and the composition thereof of the present invention have a certain temperature as an index of thermal stability,
The amount of generated gel component when heat-treated for a short time is smaller than that of conventional PVA. This is the long-term operability (long run property) in industrial hot melt molding and hot melt spinning of PVA.
In consideration of the above, it can be said that the vinyl alcohol-based polymer and the composition thereof of the present invention are remarkably excellent in industrial hot-melt moldability and hot-melt spinnability. It is not clear why the ethylene-modified PVA of the present invention and the composition thereof exhibit high thermal stability, but the ethylene-modified PVA has a specific polymerization degree, saponification degree, carboxyl group and lactone ring content, 1,2-glycol bond. It is presumed to be caused by the presence of a specific alkali metal, specifically having a specific ethylene-modified amount and a specific carboxyl group and lactone ring amount.

The vinyl alcohol-based polymer or composition of the present invention has a range in which the objects and effects of the present invention are not impaired.
If necessary, fillers, processing stabilizers such as copper compounds, weathering stabilizers, coloring agents, UV absorbers, light stabilizers, antioxidants, antistatic agents, flame retardants, plasticizers, other plasticizers Suitable additives such as resins, lubricants, fragrances, foaming agents, deodorants, extenders, release agents, release agents, reinforcing materials, fungicides, preservatives, crystallization rate retarders, etc. Can be. In particular, when an organic stabilizer such as hindered phenol, a copper halide compound such as copper iodide, or an alkali metal halide compound such as potassium iodide is added as a heat stabilizer, the melt retention during molding and fiberization is stabilized. It is preferable because the property is improved.

The above-mentioned plasticizers further reduce the melting point to further improve the hot-melt moldability and the hot-melt spinnability, impart the stretchability at the time of fiberization, and further obtain the molded articles and fibers obtained. Has the effect of imparting flexibility and toughness to the steel. The plasticizer is not particularly limited as long as it can reduce the glass transition point and melt viscosity of PVA.
For example, glycerin, 1,3-butanediol, 2,3
Diols such as butanediol; ethylene glycol, diethylene glycol, triethylene glycol,
Tetraethylene glycol, polyethylene glycol,
Polypropylene glycol, trimethylene glycol,
Glycols such as tetramethylene glycol, pentamethylene glycol, hexamethylene glycol and propylene glycol; glycerin derivatives in which ethylene oxide and propylene oxide are added to polyhydric alcohols such as sorbitol, glycerin and diglycerin, sorbitol, pentaerythritol, sugars, Polyethers, phenol derivatives such as bisphenol A and bisphenol S, amide compounds such as N-methylpyrrolidone, trimethylolpropane, diglycerin, 3-methyl-1,3,5 pentanetriol, a small amount (20% or less) of water Any known materials such as, but not limited to, can be used. The amount of the plasticizer added is preferably 30 parts by weight or less, more preferably 20 parts by weight or less, and even more preferably 10 parts by weight or less based on 100 parts by weight of the vinyl alcohol-based polymer. Further, examples of the other thermoplastic resin include general-purpose resins such as polyethylene, polystyrene, and ABS resin.

The above-mentioned fillers increase the hardness and rigidity to give a feeling of weight, exhibit anti-blocking properties, and further control the rate of water disintegration and biodegradability of the obtained molded articles and fibers. It has the effect of doing. Fillers include kaolin, clay, talc, acid clay, silica, alumina, diatomaceous earth, bentonite, montmorillonite, Kibushi clay, Frogme clay, waxite, alumite, porcelain clay, feldspar, asbestos, perlite, calcium carbonate Well-known inorganic fillers such as magnesium hydroxide, carbon black, titanium oxide, mica, zirconium oxide, boron nitride, aluminum nitride, shirasu, glass, glass fiber, and organic materials such as urea-formalin resin, melamine-formalin resin Fillers. The average particle size of the inorganic material that can be used in the present invention is not particularly limited, but is 0.1 to 100 μm.
m is preferred. The amount of the filler is not particularly limited, but may be 4 to 100 parts by weight of the vinyl alcohol polymer.
It is preferably at most 00 parts by weight, more preferably at most 200 parts by weight.

The method of adding the above-mentioned additives to the vinyl alcohol-based polymer of the present invention is not particularly limited, and stabilizers, plasticizers, fillers and additives are added to the vinyl alcohol-based polymer. Alternatively, these may be melt-kneaded and pelletized. Kneading and pelletizing while separately charging a vinyl alcohol-based polymer, a stabilizer, a plasticizer, a filler, and an additive in a fixed ratio in a melt kneader may be no problem.

Examples of the method for melt-molding the vinyl alcohol polymer of the present invention include extrusion molding, injection molding, and the like.
Extrusion film forming method from T-die, inflation film forming method, compression molding method, transfer molding method, reinforced plastic molding method, hollow molding method, press molding method, blow molding method, calender molding method, foam molding method, vacuum molding method And air pressure molding method. If desired, another thermoplastic resin can be laminated. Further, the vinyl alcohol-based polymer of the present invention can naturally be formed from a solution form using a solvent such as water or dimethyl sulfoxide. By these methods, molded articles of arbitrary shapes such as films, sheets, tubes, bottles, etc. can be obtained.

The production of the fiber comprising the vinyl alcohol polymer of the present invention can be carried out by using a known aqueous wet spinning apparatus, aqueous dry spinning apparatus, solvent wet spinning apparatus and melt spinning apparatus. The production method using a melt spinning device is preferable because the system polymer has a feature of excellent thermal stability. In the melt spinning method, P
It is obtained by melt-kneading VA pellets, guiding the melted polymer stream to the spinning head, measuring with a gear pump, and winding the yarn discharged from the nozzle. The fiber discharged from the spinning nozzle may be subjected to a stretching treatment, a heat treatment, and a shrinking process. The stretching method is usually hot stretching, but may be performed using any of hot air, a hot plate, a hot roller, a water bath and the like. The heat treatment may be performed simultaneously with or after the stretching. The heat treatment may be performed by applying shrinkage to the drawn fiber. The fiberization conditions such as spinneret temperature, shear rate, draft, stretching ratio, stretching conditions, heat treatment temperature, heat treatment conditions, and shrinkage vary depending on the vinyl alcohol polymer used and the purpose, and are appropriately adjusted.

The melt-spun fiber comprising the vinyl alcohol-based polymer of the present invention has a feature that it is completely dissolved in water at 90 ° C. or lower. Even if the dissolved PVA is released to nature as it is, it is eventually decomposed into water and carbon dioxide gas, but it is environmentally preferable to treat it with activated sludge because it is decomposed earlier.

From the PVA fibers comprising the vinyl alcohol polymer of the present invention, binder fibers for papermaking, binder fibers for nonwoven fabric, staples for dry nonwoven fabric, staples for spinning, multifilaments for woven fabrics, multifilaments for knitting, Cement reinforcing material, rubber reinforcing material, chemical lace base fabric, hollow fabric, water-soluble rope, fishing line, sewing thread, water-soluble packaging material, sanitary materials, medical disposable products, agricultural wear materials, filters, wipers, And the like.

Furthermore, the specific ethylene modification amount of the present invention,
The degree of polymerization, the degree of saponification, the amount of carboxyl groups and lactone rings, the amount of 1,2-glycol bonds, the vinyl alcohol polymer having a hydroxyl group, and the composition containing a specific amount of alkali metal are compared with those of conventional PVA. Therefore, the oxygen barrier property is remarkably excellent, and it is useful as a resin for an oxygen barrier film. That is, the vinyl alcohol polymer of the present invention and the composition thereof have an oxygen permeation amount measured by a specific method shown below, which is an index of an oxygen barrier,
Less than conventional PVA. It is not clear why the ethylene-modified PVA of the present invention and the composition thereof exhibit high oxygen barrier properties, but the ethylene-modified PVA has a specific degree of polymerization, saponification degree, carboxyl group and lactone ring content, 1,2-glycol bond. Amount, having a hydroxyl group and containing a specific alkali metal, especially those containing a specific ethylene-modified amount and a specific carboxyl group and lactone ring amount, and those containing a specific alkali metal. Presumed.

The measurement of the amount of oxygen permeation was performed according to the vinyl alcohol of the present invention.
A film obtained by forming a coal-based polymer into air
Heat treatment (preferably 100-240 ° C, more preferably
120-200 ° C; preferably 10-300 seconds, more
(Preferably 30 to 180 seconds), 20 ° C., 80% RH
After moisture conditioning, measure the oxygen transmission rate of the film and measure it.
The thickness of the vinyl alcohol polymer was converted to 20 μm.
It is the amount of oxygen permeation. Also, it is already in the form of a laminate
If this is the case, measure the oxygen permeation amount of the
Oxygen permeation converted to a thickness of 20 μm of the rupol-based polymer
Quantity. In the case of a laminate, some heat treatment is applied.
Whether gas barrier properties are manifested
Therefore, when measuring the amount of oxygen permeation, further heat treatment is required.
No need. Film made of vinyl alcohol polymer
Compared to the oxygen gas barrier properties of
Since the barrier property is very low, the oxygen gas
The rear property of the film made of vinyl alcohol polymer
It is substantially determined by the oxygen gas barrier property. Therefore,
Even in the case of a laminate, a vinyl alcohol-based polymer
It is possible to calculate the oxygen transmission amount by converting the thickness to 20 μm.
It is possible. Hereinafter, unless otherwise specified, oxygen permeation amount
Converts the thickness of the vinyl alcohol polymer to 20 μm
Means the amount of oxygen permeated. Acid measured by the above method
Elemental permeation amount is 15cc / m^Two・ Day ・ atm or less
Those having such an oxygen gas barrier property are preferable, and
Or 10cc / m ^Two・ Day ・ atm or less
More preferably 5 cc / m^Two・ Day ・ atm or less
You.

Examples of the base film on which the vinyl alcohol polymer is applied include a polyolefin film, a polyester film, and a polyamide film.
Base film thickness (final thickness when stretched)
Is preferably 5 to 100 μm.

In order to apply the vinyl alcohol polymer of the present invention to a substrate film to obtain a laminate, the vinyl alcohol polymer may be used alone, but a crosslinking agent is used for the purpose of imparting water resistance. It is preferable to use them in combination. Examples of the crosslinking agent include an epoxy compound, an isocyanate compound, an aldehyde compound, a silica compound, an aluminum compound, a zirconium compound, and a boron compound. Among these, silica compounds such as colloidal silica and alkyl silicate are preferable. The amount of the crosslinking agent to be added is usually 5 to 60 parts by weight, preferably 10 to 40 parts by weight, more preferably 15 to 30 parts by weight, based on 100 parts by weight of the vinyl alcohol polymer. When the amount of the crosslinking agent exceeds 60 parts by weight, the oxygen barrier property may be adversely affected.

When a vinyl alcohol-based polymer is applied to a substrate film to obtain a laminate, it is usually applied in the form of an aqueous solution of a vinyl alcohol-based polymer. The concentration of the aqueous solution is not particularly limited, but is preferably 5 to 50% by weight. If the concentration is less than 5% by weight, the drying load becomes large, and if it exceeds 50% by weight, the viscosity of the aqueous solution becomes high and the coatability is reduced.

When applying the aqueous solution of the vinyl alcohol polymer, a surfactant, a leveling agent and the like may be added. Further, lower aliphatic alcohols such as methanol, ethanol and isopropyl alcohol may be added up to about 30% by weight. By adding a lower aliphatic alcohol, coatability is improved. In addition, a fungicide, a preservative, and the like can be added to the aqueous solution of the vinyl alcohol-based polymer. The temperature at the time of applying the aqueous solution of the vinyl alcohol polymer is preferably from 20 to 80C. As a coating method, a gravure roll coating method, a reverse gravure coating method, a reverse roll coating method, and a Meyer bar coating method are suitably used. Examples of the method of applying the aqueous solution of the vinyl alcohol polymer include a method of applying after stretching or heat treatment of the base film, and a method of applying or stretching after coating. Among these methods, in consideration of workability, after the base film is stretched in one step, an aqueous solution of a resin for film application is applied, and further two-step stretching is performed, and heat treatment is performed during or after the two-step stretching. Is preferred. Thickness of vinyl alcohol polymer (final thickness when stretched)
Is preferably 0.1 to 20 μm.

An adhesive component layer may be formed between the vinyl alcohol polymer film layer and the base film layer for the purpose of improving the adhesiveness. The adhesive component can be applied to the surface of the base film before applying the aqueous solution of the vinyl alcohol-based polymer, or can be used by mixing with the aqueous solution of the vinyl alcohol-based polymer.

In the gas barrier laminate film, a heat seal resin layer is usually further formed on a vinyl alcohol polymer film layer. The formation of the heat seal resin layer is usually performed by an extrusion lamination method or a dry lamination method. As heat seal resin, HD
Polyethylene resins such as PE, LDPE and LLDPE, PP resins, ethylene-vinyl acetate copolymers, ethylene / α-olefin random copolymers, ionomer resins and the like can be used.

The presence or absence of stretching and the heat treatment temperature are not particularly limited, but the vinyl alcohol polymer is usually coated at a temperature suitable for each resin such as a stretched polyolefin film, polyester film or polyamide film. After that, heat treatment is performed in the air or the like. The heat treatment temperature is 140 ° C for polyolefin film.
170 ° C., and 140 ° C. to 240 ° C. for polyester films and polyamide films. The heat treatment of the film layer composed of a vinyl alcohol polymer
Usually, it is heat-treated simultaneously with the base film.

The specific ethylene modification amount obtained in the present invention,
A vinyl alcohol polymer having a degree of polymerization, a degree of saponification, a carboxyl group and a lactone ring amount, a 1,2-glycol bond amount, and a hydroxyl group and a composition thereof include a fiber sizing agent, a fiber treating agent, a fiber processing agent, and a fiber product. Sizing agent, paper clear coating, paper pigment coating agent, paper internal sizing agent, paper processing agent such as binder for thermal paper overcoat, pressure-sensitive adhesive, antifogging agent, paint, organic and inorganic pigment Dispersing agents, polymerization dispersion stabilizers for emulsions, polymerization dispersion stabilizers for PVC, adhesives for paper, wood, plastics, etc., binders for non-woven fabrics, binders for fibers, binders for ceramics, various construction materials such as gypsum boards and fiber boards Binder, additive for cement and mortar, hot melt adhesive, image forming material, photosensitive resin, formal resin and butyral tree Polyvinyl acetal raw materials etc., gel base material, a film, fibers, sheets, moldings (films, fibers, sheets, tubes, nonwovens, etc.), can be used for soil improvement agent. Further, utilizing the characteristics of the vinyl alcohol polymer of the present invention, it is possible to use the vinyl alcohol polymer alone or in combination with unmodified PVA or other modified PVA, starch (and modified products thereof), cellulose derivatives, gums, gelatin, casein and the like. It is used in combination with other types of polymers and with plasticizers.

[0061]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples. In the following Examples and Comparative Examples, “parts” and “%” mean on a weight basis unless otherwise specified. In addition, the obtained ethylene-modified PVA was analyzed for water solubility, water resistance, and low-temperature storage stability in the following manner.

[Method of Analyzing Ethylene-Modified PVA] PVA
The analysis method of JIS-K6726 is used unless otherwise specified.
Followed. The ethylene-modified amount of the present invention is a modified polyvinyl ester, and the total content of a carboxyl group and a lactone ring, the amount of 1,2-glycol bond and the content of a hydroxyl group of three hydroxyl groups are 500 MHz using a modified PVA.
It was determined as described above from measurement using a proton NMR (JEOLX-500) apparatus. The melting point of the modified PVA of the present invention is determined by using DSC (Mettler, TA3000) in nitrogen at a heating rate of 10 ° C./min to 250 ° C., then cooling to room temperature, and then again at a heating rate of 10 ° C./min. The temperature at the peak top of the endothermic peak indicating the melting point of PVA when the temperature was raised to 250 ° C. was examined. The content of the alkali metal was determined by an atomic absorption method.

[Water solubility of ethylene-modified PVA] A predetermined amount of PVA was dispersed in distilled water so that the dissolved concentration became 10%, and the mixture was heated and stirred at a temperature of 95 ° C. for 3 hours.
A aqueous solution was prepared. Subsequently, it cooled to 20 degreeC and evaluated visually. The results are indicated by the following symbols. 5: Completely dissolved in water, the aqueous solution is colorless and transparent. 4: Dissolves completely in water, but the aqueous solution is cloudy. 3: Almost soluble in water, but partially insoluble. 2: There are considerable insolubles. 1: Does not dissolve at all.

[Water Resistance of Ethylene-Modified PVA] The prepared aqueous PVA solution was cast at 50 ° C. to form a 50 μm film. A part of the obtained film was heat-treated at 120 ° C. for 10 minutes. The test sample film was taken out after immersion in water at 20 ° C. for 24 hours, and the feeling of rubbing the film by hand was evaluated on a five-point scale. 5: The film has the same feeling as when dried and is firm. 4: The film is relatively firm, but slightly slimy. 3: The film remains, but there is a slimy feel. 2: The film remains partially, but cannot be taken out. 1: The membrane is completely dissolved.

[Low Temperature Viscosity Stability of Ethylene-Modified PVA Aqueous Solution] 300 ml of a 10% by weight aqueous PVA solution was prepared.
In a glass beaker and leave it at 5 ° C for 1 day.
The ratio of the viscosity after standing (η1 day) to the initial viscosity at 5 ° C. (η initial) (low temperature thickening ratio = η1 day / η initial) was determined. The measurement was performed at 5 ° C. using a B-type viscometer (rotation speed: 12 rpm).

Example 1 [Production of ethylene-modified PVA] Vinyl acetate 107.2 k was placed in a 250-L pressure reactor equipped with a stirrer, a nitrogen inlet, an ethylene inlet, an initiator addition port, and a delay solution addition port.
g, methanol 42.8 kg and maleic anhydride 1
After charging 5.6 g, the temperature was raised to 60 ° C., and the inside of the system was replaced with nitrogen by bubbling nitrogen for 30 minutes. Then, ethylene was introduced and charged so that the reaction tank pressure became 5.9 kg / cm ² . A 2.8 g / L solution of 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile) (AMV) dissolved in methanol was prepared as an initiator, and nitrogen was replaced by bubbling with nitrogen gas. did. A 5% concentration solution of maleic anhydride dissolved in methanol was prepared as a delay solution, and nitrogen replacement was performed by bubbling with nitrogen gas. After adjusting the internal temperature of the polymerization tank to 60 ° C., 204 ml of the initiator solution was injected to start polymerization. During the polymerization, ethylene was introduced to raise the reaction vessel pressure to 5.
9 kg / cm ² , the polymerization temperature was maintained at 60 ° C., AMV was used at 640 ml / hr using the above-mentioned initiator solution, and maleic anhydride was used using the above-mentioned delay solution to polymerize vinyl acetate and maleic anhydride in the polymerization system. Polymerization was carried out by continuous addition while keeping the acid ratio constant. After 4 hours, when the polymerization rate reached 30%, the polymerization was stopped by cooling.
At this point, the total amount of the maleic anhydride delay solution added by delay was 1400 ml. After the reaction vessel was opened to remove ethylene, nitrogen gas was bubbled through to completely remove ethylene. Next, unreacted vinyl acetate monomer was removed under reduced pressure to obtain a methanol solution of polyvinyl acetate. To the obtained polyvinyl acetate solution, 333 g of a methanol solution of polyvinyl acetate adjusted to a concentration of 30% by adding methanol (polyvinyl acetate 1 in the solution).
(00g), an alkali solution (10% NaOH solution in methanol) having an alkali solution of 46.5 g (molar ratio [MR] 0.10 to vinyl acetate unit in polyvinyl acetate) was added to perform saponification. About 1 minute after the addition of the alkali, the gelled system was pulverized with a pulverizer and left at 40 ° C. for 1 hour to progress the saponification. Then, 1000 g of methyl acetate was added to neutralize the remaining alkali. After confirming the completion of neutralization using a phenolphthalein indicator, 1000 g of methanol was added to the white solid PVA obtained by filtration, and the mixture was added at room temperature for 3 hours.
It was left to wash for a period of time. After repeating the above washing operation three times,
The PVA obtained by centrifugal drainage was left in a dryer at 70 ° C. for 2 days to obtain a dried PVA (PVA-1).

[Analysis of Ethylene-Modified PVA] The obtained ethylene-modified PVA having a carboxyl group and a lactone ring
The degree of saponification of VA was 98.5 mol%. After the modified PVA was incinerated, the content of sodium measured by an atomic absorption spectrophotometer using a substance dissolved in an acid was 0.36 parts by weight based on 100 parts by weight of the modified PVA.
Further, a methanol solution of polyvinyl acetate obtained by removing unreacted vinyl acetate monomer after polymerization is precipitated in n-hexane and reprecipitated by dissolving in acetone three times.
Drying under reduced pressure at 0 ° C. for 3 days gave purified polyvinyl acetate. The polyvinyl acetate was dissolved in DMSO-D _6, 50
The content of ethylene units was 7 mol% as measured at 80 ° C. using 0 MHz proton NMR (JEOLX-500). After saponifying the above methanol solution of polyvinyl acetate at an alkali molar ratio of 0.5, the pulverized product was allowed to stand at 60 ° C. for 5 hours to progress saponification, and then methanol soxhlet was carried out for 3 days.
Drying under reduced pressure at 0 ° C. for 3 days gave purified ethylene-modified PVA having a carboxyl group and a lactone ring.
The average degree of polymerization of the PVA was 1000 when measured according to JIS K6726 of a conventional method. The content of the carboxyl group and the lactone ring, the amount of the 1,2-glycol bond and the content of the hydroxyl group having three hydroxyl groups in the purified PVA were measured at 500 MHz proton NMR (JEOL GX-50).
0) The values obtained as described above from the measurement by the apparatus were 0.246 mol%, 1.61 mol% and 87%, respectively.
Met. Further, a 5% aqueous solution of the purified modified PVA was adjusted to prepare a cast film having a thickness of 10 μm. After the film was dried under reduced pressure at 80 ° C. for one day, the melting point of PVA was measured using DSC (Mettler, TA3000) according to the method described above.
Met.

[Water solubility, water resistance and low temperature viscosity stability of ethylene-modified PVA]
A (PVA-1) was used to evaluate the water solubility by the method described above. As a result, it was completely dissolved in distilled water and the aqueous solution was colorless and transparent. In addition, when the water resistance was evaluated by the above-mentioned method, the film obtained by casting at 50 ° C. and the film subjected to a heat treatment at 120 ° C. for 10 minutes were the same firmly as the dried film before immersion in water. I felt it. Furthermore, the viscosity stability of a 10% aqueous solution of PVA at 5 ° C. was evaluated by the method described above. The viscosity of the PVA aqueous solution immediately after immersion at 5 ° C. was 450 mPa · s, and the PVA after standing at 5 ° C. for 1 day. The aqueous solution viscosity was 500 mPa · s, and the low-temperature thickening ratio was 1.
It was one time.

Examples 2 to 8, 11 to 18, 20 to 22 and 27 to 29 Vinyl ester polymers were synthesized in exactly the same manner as in Example 1 except that the conditions shown in Tables 1 and 2 were changed. Subsequently, the PVA was produced in the same manner as in Example 1 except that the vinyl ester polymer was changed to the conditions shown in Tables 3 and 4.
An A-based polymer was synthesized. Ethylene content, degree of polymerization, degree of saponification, carboxyl group and lactone ring content, 1,2-glycol bond amount of the obtained PVA-based polymer, amount of central hydroxyl group of 3 chains of hydroxyl groups by triad display with respect to vinyl alcohol unit, and PVA polymer 10
Tables 5 and 6 show the contents of alkali metals in terms of sodium relative to 0 parts by weight. Tables 13 and 14 show the water solubility, water resistance and low temperature viscosity stability of the obtained PVA-based polymer.

Comparative Examples 1 to 7, 12 to 17, 19 to 21 and 24 to 25 Change the pressure during polymerization (PVA containing no ethylene)
When synthesizing the system polymer, polymerization was carried out in a state of nitrogen sealing. ), Etc., except that the conditions shown in Tables 7 and 8 were changed, to synthesize a vinyl ester polymer in exactly the same manner as in Example 1. Subsequently, the vinyl ester-based polymer was added in Table 9
A PVA-based polymer was synthesized in exactly the same manner as in Example 1 except that the conditions shown in Table 10 were changed. Obtained PV
Ethylene content, degree of polymerization, degree of saponification, content of carboxyl group and lactone ring, 1,2-glycol bond amount of A-based polymer, amount of central hydroxyl group of three chains of hydroxyl group by triad display with respect to vinyl alcohol unit, and P
Tables 11 and 12 show the content of alkali metal in terms of sodium based on 100 parts by weight of the VA polymer. Tables 15 and 16 show the water solubility, water resistance and low temperature viscosity stability of the obtained PVA-based polymer.

As shown in Tables 13 to 16, in the evaluation of the water solubility, water resistance and storage viscosity stability at low temperature of PVA, good results were obtained only when the physical properties in the predetermined range of the present invention were satisfied. However, all of those described as comparative examples had poor results in any or all of the water solubility, water resistance, and stability of standing viscosity at low temperature. For example, Comparative Examples 26 to 34 having no ethylene modification have poor water resistance or viscosity stability, and Comparative Examples 35 and 36 having modifications other than ethylene.
Then it does not dissolve in water at all. In Comparative Example 48, there is no problem with water solubility or water resistance, but the aqueous solution gels after one day due to poor storage stability at low temperatures, and is difficult to handle in operation. In Example 40, the storage viscosity stability at low temperature (η1 day / η initial period) was 24.6, which seems to be not as good as the others. However, the degree of polymerization and the degree of saponification are the same as those of Example 40. When the same evaluation was performed, the solution gelled after one day in the case of having no ethylene modification, whereas the viscosity of the aqueous solution after one day in Example 40 was 270.
The solution state is maintained at mPa · s, and improvement in stability due to ethylene modification is recognized.

Example 9 and Comparative Example 8 In Example 9, 76.6 kg of vinyl acetate, 73.3 kg of methanol and 73.3 kg of methanol were placed in a 250-L pressure reactor equipped with a stirrer, a nitrogen inlet, an ethylene inlet, and an initiator inlet. 217 g of allyl glycidyl ether was charged and the system was replaced with nitrogen in the same manner as in Example 1. Then the reactor pressure,
A vinyl ester polymer containing allyl glycidyl ether was polymerized in exactly the same manner as in Example 1 except that the conditions shown in Table 1 were changed, such as the amount of AMV and allyl glycidyl ether as a comonomer were not continuously added. After 3 hours, when the polymerization rate reached 20%, the polymerization was stopped by cooling, the reaction vessel was opened to remove ethylene, and then nitrogen gas was bubbled to completely remove ethylene. Next, unreacted vinyl acetate monomer was removed under reduced pressure to obtain a methanol solution of polyvinyl acetate. 0.54 g of 3-mercaptopropionic acid was added to 286 g of methanol solution of polyvinyl acetate (100 g of polyvinyl acetate in the solution) adjusted to have a concentration of 35% by adding methanol to the obtained polyvinyl acetate solution. After adding 0.1 g of sodium acetate and stirring at 50 ° C. for 2 hours, saponification was performed by adding 46 g of an alkaline solution (a 10% methanol solution of NaOH). After about 1 minute from the addition of the alkali, the gelled system was pulverized with a pulverizer and left at 40 ° C. for 1 hour to progress the saponification. Neutralized. After confirming the completion of the neutralization using a phenolphthalein indicator, 1000 g of methanol was added to the white solid PVA obtained by filtration and washed at room temperature for 3 hours. After repeating the above washing operation three times, the PVA obtained by centrifugal dewatering was placed in a dryer at 70 ° C.
And dried for 2 days to obtain an ethylene-modified PVA having a carboxyl group (PVA-9). The analysis results and evaluation results of the ethylene-modified PVA are shown in Tables 5 and 13. Comparative Example 8 is a carboxyl group-modified PVA (PVA-37) in exactly the same manner as in Example 9 except that the conditions under ethylene pressure were changed to the conditions shown in Tables 7 and 9, for example, the polymerization was performed in a nitrogen sealed state. ) Got. Table 11 and Table 15 show the analysis results and evaluation results of the PVA.

Example 10 and Comparative Example 9 Example 10 and Comparative Example 9 were composed of PVA-2 and PVA.
Concentrated hydrochloric acid was added to a 10% aqueous solution obtained by dissolving 100 g of each of -31 in distilled water to adjust the pH of the aqueous solution to 1 and then 0.52 g of 4-oxo-butanoic acid was added thereto. After stirring for an hour, the reaction solution was neutralized with a NaOH solution to adjust the pH of the solution to 7, the aqueous solution was poured into MeOH, and the precipitated PVA was separated by filtration and subjected to Soxhlet extraction (MeOH) for 3 days. Ethylene-modified P having a carboxyl group which was left for 2 days at 70 ° C. and dried
VA (PVA-10) and carboxyl group-modified PVA
(PVA-37) was obtained. The analysis results of each PVA are shown in Tables 5 and 11, and the evaluation results are shown in Tables 13 and 15.
Are shown below.

As shown in Table 5, when a reaction product of polyvinyl acetate having an epoxy group and thiol having a carboxyl group was saponified as in Example 9,
When an aldehyde compound having a carboxyl group is added to PVA by acetalization as described in
It can be seen that VA can be introduced. Table 13
As shown in Examples 38 and 39, the carboxyl group and the lactone ring introduced by using such a method have functions completely different from those introduced by a method such as copolymerization.

Examples 19, 25, 26 and Comparative Example 18 The comonomer ethyl vinyl ether or vinyltrimethoxysilane was added only during the polymerization preparation operation, and was not added continuously during the polymerization. Ternary copolymer modified PVA (PVA-19, PVA) in the same manner as in Example 1 except that the conditions shown in Table 10 were changed
A-25, PVA-26, and PVA-47). Tables 6 and 12 show the analysis results of each PVA, and Tables 14 and 16 show the evaluation results.

COMPARATIVE EXAMPLES 10 AND 11 Isobutene-modified PVA was prepared in exactly the same manner as in Example 19 except that isobutene or 1-octene was copolymerized instead of ethylene and the conditions shown in Tables 7 and 9 were used.
(PVA-39) and 1-octene-modified PVA (PV
A-40) was obtained. The analysis results and evaluation results of each PVA are shown in Tables 11 and 15, respectively. These modified PVAs were insoluble in distilled water. Therefore, 20 ° C
Table 4 shows the degree of polymerization estimated from the value obtained by measuring the viscosity of the 4% concentration DMSO solution in Table 1. The degree of saponification was determined in accordance with JIS-K6726 except that the modified PVA was dissolved in a 6/4 solution of water / methanol.

Examples 23 and 24 and Comparative Examples 22 and 23 Examples 23 and 24 differ from Example 2 in that PVA-2
In the same manner as in Example 2 except that the PVA paste obtained by polymerization at the time of synthesizing the PVA was used, except that the method of washing the PVA shown in Table 4 was changed, PVA having a different alkali metal content was used.
A (PVA-23, PVA-24) was obtained. Comparative Example 22
And 23 used PVA-paste obtained by polymerization at the time of synthesizing PVA-31 in Comparative Example 2, except that the method of cleaning PVA shown in Table 10 was changed in exactly the same manner as in Comparative Example 2 except that PVA-31 was changed. 51 and PVA-52 were obtained.
Tables 6 and 12 show the analysis results of each PVA, and Tables 14 and 16 show the evaluation results.

[0078]

[Table 1]

[0079]

[Table 2]

[0080]

[Table 3]

[0081]

[Table 4]

[0082]

[Table 5]

[0083]

[Table 6]

[0084]

[Table 7]

[0085]

[Table 8]

[0086]

[Table 9]

[0087]

[Table 10]

[0088]

[Table 11]

[0089]

[Table 12]

[0090]

[Table 13]

[0091]

[Table 14]

[0092]

[Table 15]

[0093]

[Table 16]

[Thermoformability of Ethylene-Modified PVA] Examples 59 to 78 and Comparative Examples 51 to 67 PVA pellets were produced by extruding under any of the following molding temperature conditions, and were molded according to the following five-step evaluation. Was evaluated for thermoformability. Tables 17 to 19 show the results. -Pelletization conditions Extruder: Labo Plastmill manufactured by Toyo Seikan Co., Ltd. Screw: Biaxial, same direction, 25 mmφ, L / D = 26 Discharge rate: 3.0 kg / hr (Pelletization temperature condition A) Set temperature (cylinder) Part): 230 ° C Set temperature (die part): 130 ° C (pelleting temperature condition B) Set temperature (cylinder part): 210 ° C Set temperature (die part): 120 ° C (pelletizing temperature condition C) Set temperature (cylinder) Part): 200 ° C. Set temperature (die part): 110 ° C. ・ Evaluation of thermoformability 5: No smoke is generated during molding, and there is no decomposition odor. 4: Smoke is generated to the extent that molding cannot be performed, but there is no decomposition odor. 3: Smoke is generated during molding, and a slight decomposition odor is generated. 2: Smoke is generated considerably during molding, and decomposition odor is generated. 1: Smoke was generated violently during molding, and the decomposition odor was so severe that molding was not possible. Or, since it has a high melting point, it contains a large amount of undissolved substances and cannot be used for molding.

[Thermal Stability of Ethylene-Modified PVA] Examples 59 to 78 and Comparative Examples 51 to 67 Using the pellets obtained by the above method as raw materials, melt extrusion molding was carried out under any of the following molding temperature conditions. A film was formed, and the thermal stability of the polymer was evaluated according to the following five-grade evaluation. Tables 17 to 19 show the results. Melt extrusion molding conditions Extruder: Labo Plastomill manufactured by Toyo Seikan Co., Ltd. Screw type: Full flight screw Screw rotation speed: 200 rpm Motor load current: 3.3 amps Discharge amount: 2.2 kg / hr Film thickness: 40 μm ( Extrusion temperature condition A) Cylinder 1: 180 ° C Cylinder 2: 210 ° C Cylinder 3: 230 ° C Cylinder 4: 230 ° C Cylinder 5: 230 ° C Die temperature: 225 ° C (Extrusion temperature condition B) Cylinder 1: 160 ° C Cylinder 2 Cylinder 3: 210 ° C Cylinder 4: 210 ° C Cylinder 5: 210 ° C Die temperature: 205 ° C (Extrusion temperature condition C) Cylinder 1: 150 ° C Cylinder 2: 180 ° C Cylinder 3: 200 ° C Cylinder 4: 200 ° C Cylinder 5: 200 ° C Die temperature: 19 ° C ・ Evaluation of thermal stability of polymer Twenty pieces were cut at random into a film having a width of 200 mm and a length of 200 mm from the film obtained under the above conditions, and the average per piece of gel (fish eye) derived from the gel was obtained. The number was determined by the following five-step evaluation. 5: The number of spots is less than 0.2 4: The number of spots is 0.2 or more and less than 0.6 3: The number of spots is 0.6 or more and less than 1.5 2: The number of spots is 1.5 or more Less than 4.0 1: 4.0 or more

[Molded Physical Properties of Injection Molded Product of Ethylene-Modified PVA] Examples 59 to 78 and Comparative Examples 51 to 67 Using the pellets obtained by the above method as raw materials, under any of the following molding temperature conditions: A test piece having a width of 50 mm, a length of 100 mm, and a thickness of 3 mm was prepared by injection molding, and the flexural modulus was measured. The results are shown in Tables 17 to 19. Injection molding conditions Molding machine: FS80S12ASEE manufactured by Nissei Plastics Co., Ltd. Injection capacity: 127 cm ³ / shot Mold clamping force: 80 ton Mold temperature: 60 ° C. Injection pressure: (primary) 950 kgf / cm ² (secondary) 560 kgf / cm ² (tertiary) 400 kgf / cm ² screw backpressure: 10 kgf / cm ² injection time: 10 sec. Cooling time: 40 sec. (Injection molding temperature condition A) After cylinder: 220 ° C. In cylinder: 235 ° C. Before cylinder: 235 ° C. Nozzle temperature: 230 ° C. (Injection molding temperature condition B) After cylinder: 200 ° C. In cylinder: 215 ° C. Before cylinder: 215 ° C. Nozzle Temperature: 210 ° C. (injection molding temperature condition C) After cylinder: 190 ° C. In cylinder: 205 ° C. Before cylinder: 205 ° C. Nozzle temperature: 200 ° C. Flexural modulus measurement Measured in accordance with JIS K7203.

[Molded Physical Properties of Blow-Molded Product of Ethylene-Modified PVA] Examples 59 to 78 and Comparative Examples 51 to 67 Using the pellets obtained by the above method as raw materials, under any of the following molding temperature conditions: A bottle was prepared by blow molding, and the impact resistance of the molded product was evaluated according to the following five-grade evaluation. The results are shown in Tables 17 to 19. -Blow molding conditions Molding machine: hollow molding machine manufactured by Suzuki Iron Works Screw: 40φ, L / D = 19 Screw rotation speed: 500 rpm Mold nozzle: 13φ / 16φ Bottle capacity: 50 ml (wall thickness 0.85 mm) (Molding temperature conditions A) Cylinder 1: 210 ° C Cylinder 2: 225 ° C Cylinder 3: 230 ° C Cylinder 4: 230 ° C Cylinder 5: 230 ° C Die temperature: 225 ° C (Forming temperature condition B) Cylinder 1: 190 ° C Cylinder 2: 205 ° C Cylinder 3 Cylinder 4: 210 ° C Cylinder 5: 210 ° C Die temperature: 205 ° C (Molding temperature condition C) Cylinder 1: 180 ° C Cylinder 2: 195 ° C Cylinder 3: 200 ° C Cylinder 4: 200 ° C Cylinder 5: 200 ° C Die Temperature: 195 ° C ・ Evaluation of impact resistance Antifreeze in the obtained bottle After fully filling with a mechanical lubricating oil (freezing point: -20 ° C) and sealing, leave it for one week (20 ° C, 65% RH or -5 ° C) or one month (-5 ° C) to fill the oil In this state, the bottles (20 samples each) were naturally dropped on a wooden floor from a height of 2.5 meters, and evaluated according to the following five scales by the average value of the number of cracks generated in the bottles. 5: Number of cracks 1 or less 4: Number of cracks 2 to 4 3: Number of cracks 5 to 7 2: Number of cracks 8 to 10 1: Number of cracks 11 or more

[0098]

[Table 17]

[0099]

[Table 18]

[0100]

[Table 19]

Comparative Examples 52 and 61 and Comparative Example 67 The melt moldability of fully saponified PVA in which only a predetermined amount or less of ethylene was modified was high because the melting point of the polymer was high without the addition of a plasticizer. Only a large amount of pellets remained in the pellets and were not suitable for use in melt molding.

Comparative Examples 53 and 54 and Comparative Example 57 Intermediate saponified PVA and partially saponified PVA which are modified only with a predetermined amount or less of ethylene generally have poor thermoformability and thermal stability, and are obtained in pellets and melt-molded films. Both are intensely colored, and in the case of a film, the number of spots is extremely large and the utility is poor. In addition, even a PVA obtained by modifying a predetermined amount of ethylene has a saponification degree of less than a predetermined amount.
VA also has poor thermoformability and thermal stability, and is poor in practicality.

Comparative Example 56 Even with PVA having a predetermined amount of ethylene modification and saponification degree,
PVA having a degree of polymerization of a predetermined amount or less is excellent in thermoformability and thermal stability, but is insufficient for practical use because the impact resistance of the molded product is extremely low.

Comparative Example 58 and Comparative Example 59 P having a carboxyl group and a lactone other than predetermined amounts
VA has poor thermoformability and thermal stability as a whole, and is poor in practicality particularly because the number of bumps in a melt-molded film is very large.

Comparative Example 60 PVA having a melting point equal to or less than a predetermined amount is excellent in impact resistance.
In the case of injection molding or the like, the releasability from a mold is poor, which is not preferable from the viewpoint of productivity of a molded product. Further, the obtained molded product has poor form stability, and there is a problem in practicality in a molded product such as a bottle. Furthermore, a molten film is not practical because it is easily blocked.

Comparative Examples 62 and 63 PVA having a 1,2-glycol bond of a predetermined amount or less
Has poor thermal stability, and is particularly poor in practicality due to the extremely large number of bumps in the melt-molded film. In addition, PVA having a 1,2-glycol bond of a predetermined amount or more has poor thermoformability and thermal stability, and similarly has a very large number of bumps, and thus has poor practicality.

Comparative Examples 64 and 65 PVA containing only a predetermined amount or less of an alkali metal is apt to gel and has a very large number of bumps in a melt-molded film, so that it is not practical. PVA containing a predetermined amount or more of an alkali metal is not practically preferable because it has a strong decomposition odor, easily gelates, and significantly deteriorates both thermoformability and thermal stability.

As described above, the PVA other than the various predetermined amounts of the present invention has poor thermoformability and thermal stability, and molded products such as bottles obtained from these PVAs generally have a reduced impact resistance. It is not suitable for use in melt molding because the color and transparency of the molded product are also reduced.

[Oxygen Barrier Property of Ethylene-Modified PVA] Examples 79 to 95 and Comparative Examples 68 to 73, 75 to 85 Table 20 and Table 21 were added to distilled water in a separable flask.
The PVA-based polymer shown in (1) was gradually added with stirring and uniformly dispersed, and then heated to 95 ° C. and stirred for 2 hours or more to completely dissolve. After cooling to about 50 ° C., the mixture was filtered and further cooled to room temperature to prepare a PVA aqueous solution having a concentration shown in Tables 20 and 21. Using the application bar,
The surface of the base film having a thickness of 15 μm shown in Tables 20 and 21 was coated with the PVA solution obtained above at 50 ° C. and dried at 120 ° C.
At 120 ° C. for 120 seconds in air. P
The thickness of the VA coating layer was 4.0 μm. PV
A Oxygen permeation amount (OTR) of A coating film (laminate of base material and PVA) (unit: cc / m ² · day · a)
tm) are shown in Tables 20 and 21. The oxygen permeation amount (OTR) of the PVA coating film (laminate of the substrate and PVA) (unit: cc / m ² · day · atm)
Means that the laminate is kept at 20 ° C. and 80% relative humidity for 5
It was measured after conditioning for one day. The oxygen permeation amount shown in the following table is a value obtained by converting the thickness of the resin for film application into 20 μm.

Examples 96 to 100 and Comparative Examples 86 to 8
7. PVA aqueous solutions having the concentrations shown in Tables 20 and 21 were prepared in exactly the same manner as in Example 79. Next, using a 15 μm-thick OPET as a base film, the above PVA solution was coated at 50 ° C. with a coating bar, dried at 130 ° C., and then subjected to a heat treatment at a temperature shown in Tables 20 and 21 for 120 seconds in air. Went inside. The thickness of the PVA coating layer was 3 μm. Tables 20 and 21 show the oxygen permeation amount of the laminate.

The PVA having a carboxyl group and a lactone ring which does not contain ethylene or has only a small amount of ethylene used in Comparative Examples 68 to 73 has reduced oxygen barrier properties of the obtained laminate. In the case of Comparative Example 75 using the ethylene-modified PVA having a high degree of polymerization and the example of Comparative Example 76 using the ethylene-modified PVA having a low degree of polymerization, P
The film surface of the VA coating layer was slightly out of contact. Comparative Example 77 using the ethylene-modified PVA having a low molar fraction of the central hydroxyl group of three hydroxyl groups, and Comparative Examples 78 to 79 using the ethylene-modified PVA in which the content of the carboxyl group and the lactone ring is out of a predetermined range. Comparative example 7
7 and Comparative Examples 80 to 84 using the ethylene-modified PVA whose melting point, 1,2-glycol bond amount and alkali metal content were out of the predetermined ranges were all obtained. Decreased.

Comparative Example 74 Since the PVA (PVA-39) used was insoluble in water, the PVA was prepared using a mixed solvent of water / methanol = 7/3.
A laminate was obtained in exactly the same manner as in Example 79 except that an aqueous solution was prepared. Table 21 shows the oxygen permeation amount of the laminate. A laminate using PVA in which the comonomer of the PVA-based polymer used in the examples was changed from ethylene to 1-octene has poor oxygen barrier properties.

Comparative Example 88 A PVA film obtained by casting a PVA aqueous solution was cast on a base film having a thickness of 15 μm shown in the table using an isocyanate-based adhesive by a dry laminating method, except that: A laminate was obtained in the same manner as in Example 79. The thickness of the PVA coating layer was 2.0 μm. Table 21 shows the oxygen permeation amount of the laminate. The laminated body laminated by the dry lamination method has an inferior oxygen barrier property as compared with the laminated body obtained by the aqueous solution coating method.

[0114]

[Table 20]

[0115]

[Table 21]

[Biodegradability of ethylene-modified PVA] Example 101 The biodegradability of ethylene-modified PVA having a carboxyl group and a lactone ring was measured using a continuous wastewater treatment tester comprising a 5 L aeration tank and a 2 L precipitation tank. evaluated. After dissolving PVA-1 shown in Table 5 in water, PVA-1, glucose, L-glutamic acid, ammonium chloride, potassium chloride, potassium disodium phosphate, dipotassium diphosphate potassium, calcium chloride, sulfuric acid 700 and 360, 180, 120, 8.4, 300 iron and magnesium sulfate
Each concentration of 300, 6.7, 1.5, 0.7 (mg / l)
After dissolving in water and adjusting the pH to 7 with caustic soda, the solution was sterilized and used for the medium. Use sludge from sewage treatment plant,
The initial sludge concentration was 4400 ppm. The supply rate of the culture medium to the aeration tank was 5 L / day, the amount of aeration was 2 L / day, and the liquid overflowing from the aeration tank was transferred to the sedimentation tank, where the sediment was separated, and then fed back to the aeration tank as sludge. After a treatment test at a treatment temperature of 30 ° C. for three consecutive days, the suspended sludge was collected from the center of the aeration tank with a pipette. Next, after performing centrifugation, the PVA concentration in the supernatant was determined by the iodine method, and the PVA concentration was 4.1 ppm.
This is 99.4% PVA by activated sludge treatment for 3 days.
Is biodegraded.

Examples 102 to 109 and Comparative Examples 89 to
94 Instead of the PVA-based polymer used in Example 101, Table 22 was used.
Example 101 except that the PVA-based polymer shown in
The biodegradability of an ethylene-modified PVA having a carboxyl group and a lactone ring was evaluated in exactly the same manner as described above. Measurement result of PVA concentration in sludge liquid after treatment for 3 days and P
Table 22 shows the biodegradability of VA. As is clear from Table 22, the ethylene-modified PVA having a carboxyl group and a lactone ring of the present invention was 97% in a short period of only 3 days.
The above biodegradability was exhibited. On the other hand, the biodegradability of the PVA-based polymer outside the scope of the present invention was 94% or less, and the biodegradability without ethylene contained was 80% or less.

[0118]

[Table 22]

[0119]

The vinyl alcohol polymer and the composition of the present invention are excellent in thermal stability, water resistance, gas barrier properties, water vapor barrier properties, low-temperature storage stability of aqueous solutions and biodegradability.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) C08F 210: 02) F-term (Reference) 4J002 BE031 BE061 EG026 FD010 FD020 GA02 GF00 GH02 GJ01 GK01 GK02 GL00 HA04 4J100 AA02P AD02Q AG02Q AG03Q AG04Q AG05Q AG08Q AJ02R AJ08R AJ09R AK01R AK31R AK32R AL03R AM15R AM17R BA17R BC43Q BC53H CA05 CA25 CA31 DA01 DA22 DA24 DA32 DA36 DA71 HA08 HA17 HA43 HB39 HC16 HC69 HC70 JA01 JA03 JA11

Claims (5)

[Claims] 1. An ethylene unit content of 2 to 19 mol%,
A vinyl alcohol polymer having a degree of polymerization of 200 to 2000, a degree of saponification of 80 to 99.99 mol%, and a total content of carboxyl groups and lactone rings of 0.02 to 0.4 mol%. 2. The vinyl alcohol polymer according to claim 1, wherein the total content of the carboxyl group and the lactone ring satisfies the following expression 1. (Equation 1) ｛Here, the content (unit: mol%) represents the total content of the carboxyl group and the lactone ring, and P represents the viscosity average degree of polymerization of the vinyl alcohol polymer. ｝ 3. Content of 1,2-glycol bond 1.2
The vinyl alcohol polymer according to claim 1 or 2, wherein the vinyl alcohol polymer has a molar fraction of 65 to 98 mol% of a central hydroxyl group of three hydroxyl groups in triad notation with respect to the vinyl alcohol unit and a melting point of 160 to 230 ° C. 4. The molar fraction of a central hydroxyl group of three hydroxyl groups in triad notation satisfies the following equation (2).
The vinyl alcohol polymer according to the above. (Equation 2) ｛Here, the mole fraction (unit: mole%) represents the mole fraction of the central hydroxyl group of three hydroxyl groups in triad notation with respect to the vinyl alcohol unit, and Et is the ethylene content (unit: mole) contained in the vinyl alcohol polymer. %). ｝ 5. The vinyl alcohol-based polymer (A) according to any one of claims 1 to 4, based on 100 parts by weight,
A vinyl alcohol-based polymer composition containing 0.0003 to 1 part by weight of an alkali metal (B) in terms of sodium.