JP3212980B2 - Method for producing vinyl ester polymer and method for producing vinyl alcohol polymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a vinyl ester polymer and a method for producing a vinyl alcohol polymer. More specifically, the present invention relates to a method for producing a vinyl ester polymer having a high polymerization degree by seed polymerization, and a method for producing a vinyl alcohol polymer having a high polymerization degree using the vinyl ester polymer obtained by this method.

[0002]

2. Description of the Related Art Vinyl ester polymers, especially vinyl acetate polymers, are widely used as base polymers for adhesives and paints, and are extremely important as raw materials for vinyl alcohol polymers. In addition, vinyl alcohol-based polymers have excellent interface properties and strength properties as a few crystalline water-soluble polymers, so they have been used as paper processing agents, fiber processing agents, and stabilizers for emulsions. First, as is well known, it occupies an important position as a raw material for vinylon films and vinylon fibers.

The upper limit of the degree of polymerization of the conventional vinyl alcohol polymer is 2,000 from the viewpoints of processing characteristics and ease of handling and that it is difficult to obtain a raw material vinyl acetate polymer having a high degree of polymerization. There were only about 3000 special products. However, rapid advances in processing technology in recent years have made it possible to process polymers having an ultra-high degree of polymerization, thereby succeeding in bringing out previously unknown physical properties. In the case of vinyl alcohol-based polymers, by increasing the degree of polymerization, not only the physical properties in conventional applications are improved, but also new possibilities are expected in new fields such as high-strength fibers and highly durable polarizing films.

In general, a polymer having a high degree of polymerization is obtained by polymerizing at a low polymerization rate at a low temperature, and several examples of vinyl acetate have been reported. [For example, AR
Shultz; J. Am. Chem. Soc., 76 , 3422 (1954);
M. Burnett, MH George, HW Melville; J. Polym.
Sci., 16 , 31 (1955), M. Matsumoto, Y. Ohyanagi; J.
Polym. Sci, 46 , 148 (1960)] However, all of these methods are bulk polymerization methods, and since the polymerization system has an extremely high viscosity, stirring becomes difficult and a homogeneous polymer cannot be obtained. It has problems such as difficulty. Therefore, it is considered that production on an industrial scale by these bulk polymerization methods will be almost impossible.

As a method for overcoming the disadvantages of the bulk polymerization method, a method using a suspension polymerization method has been proposed (JP-A-61-148209). However, in systems with large chain transfer, such as vinyl esters, it is essential to lower the polymerization temperature in order to increase the degree of polymerization. The polymerization rate must be very low.

Further, as a method of overcoming the disadvantages of these polymerization methods, the polymerization mechanism is different from that of bulk polymerization or suspension polymerization, and even when polymerization is performed at a relatively high polymerization rate, there is almost no problem with stirring and heat removal. A low-temperature emulsion polymerization method has been proposed in which a vinyl ester polymer and a vinyl alcohol polymer having a high degree of polymerization can be obtained (Japanese Patent Application Laid-Open (JP-A) No. 63-163).
-37106). However, this low-temperature emulsion polymerization method requires a long time from the start of the addition of the initiator to the start of the polymerization, or the weight-average molecular weight (Mw) and the number-average molecular weight (Mw) of the obtained high-polymerization degree vinyl alcohol polymer. A vinyl alcohol polymer having a high molecular weight (Mn) ratio (Mw / Mn), that is, a so-called large molecular weight distribution, or an average degree of polymerization of a high polymerization degree vinyl alcohol polymer obtained is only 25,000 at the maximum. There is a problem that there is no.

Further, an anionic emulsifier is added in an amount of 0.01 to 0.6% by weight based on the vinyl chloride monomer. Thereafter, before the polymerization is completed, the nonionic emulsifier is added to the monomer.
It is known that a vinyl chloride monomer is seed-polymerized by using an emulsion obtained by adding 0.2% by weight or more to complete emulsion polymerization as a seed emulsion (JP-A-54-60389). No.). However, this method is a method for obtaining a vinyl chloride polymer emulsion having a sharp particle size distribution and a large particle size,
In this method, a vinyl ester polymer having a high degree of polymerization could not be obtained.

Further, it is possible to continuously emulsion-polymerize ethylene and vinyl acetate using a vinyl acetate polymer emulsion or an ethylene-vinyl acetate copolymer emulsion obtained by emulsion polymerization at a temperature of 40 to 75 ° C. as a seed emulsion. Known (JP-A-54-145783)
No.). However, this method could not obtain a vinyl ester polymer emulsion having a high degree of polymerization.

Further, emulsion polymerization is carried out at a temperature of 50 to 90 ° C. using monomers such as vinyl acetate and acrylic acid,
Using the obtained emulsion as a seed emulsion,
Temperature of 50-90 ° C, unit volume of reaction solution charged (1 liter)
It is known to perform seed polymerization of ethylene, styrene, acrylic acid, etc. at an initiator charging amount of 5.0 × 10 ⁻⁴ to 5.0 × 10 ⁻³ mol per unit (JP-A-54-103489).
No.). However, in this method, a vinyl ester polymer having a high degree of polymerization could not be obtained because the amount of the initiator charged was large and the polymerization temperature was high.

[0010]

SUMMARY OF THE INVENTION According to the present invention, the above-mentioned conventional problems are solved, and a vinyl ester polymer and a vinyl alcohol polymer having a higher degree of polymerization than conventional methods can be easily produced on an industrial scale. It provides a way to do that.

[0011]

Means for Solving the Problems The present inventors have conducted intensive studies to overcome the above-mentioned drawbacks of the prior art, and as a result, using a vinyl ester-based polymer emulsion as a seed emulsion, an aqueous solution per unit volume of the charged reaction solution was used. The seed polymerization of vinyl ester is carried out under the condition that the charged amount of the water-soluble initiator and the charged amount of the water-soluble initiator per one vinyl ester-based polymer particle in the seed emulsion are set within a certain range, whereby the conventional method can be used. It has been found that a vinyl ester polymer having a high degree of polymerization can be obtained. The present invention has been completed based on such findings.

That is, in the present invention, a vinyl ester polymer emulsion is used as a seed emulsion, and the amount of a water-soluble initiator charged per unit volume (1 liter) of a charged reaction solution is 1 × 10 ⁻⁸ to 2 × 10 ^−4. And a vinyl ester-based polymer in the seed emulsion is charged with a water-soluble initiator in an amount of 1 × 10 ⁻²⁸ to 1 × 10 ⁻²⁰ mol per seed. The present invention provides a method for producing a vinyl ester polymer. The present invention also provides a method for producing a vinyl alcohol-based polymer, comprising saponifying the vinyl ester-based polymer obtained by the above method.

First, a method for producing a vinyl ester polymer emulsion suitable as a seed emulsion in seed polymerization of vinyl ester will be described. As described above, the production method of this vinyl ester polymer emulsion is as follows.
It is characterized in that a vinyl ester is emulsion-polymerized at a temperature of -60 to 40 ° C using 〜20 parts by weight. The polymerization temperature in the case of emulsion polymerization of a vinyl ester is preferably as low as possible in order to suppress chain transfer. However, since the growth rate constant also decreases as the temperature decreases, if the polymerization temperature is too low, problems such as lowering of the polymerization rate and susceptibility to oxygen are caused. Therefore, the polymerization temperature is-
It needs to be 60 to 40 ° C, and -50 to 4
0 ° C is preferred, -40 to 40 ° C is more preferred, and -3
0-40 degreeC is more preferable, and -30-35 degreeC is the most preferable.

When the polymerization temperature is set to 0 ° C. or lower, it is necessary to prevent the aqueous phase as a dispersion medium from condensing, and it is necessary to prevent water-soluble alcohols, glycols, glycerins, dimethyl sulfoxide, inorganic salts and the like. Addition of a freezing point depressant to the aqueous phase is essential. Specific examples of the freezing point depressant include methanol, ethanol, propanol, t-butanol, ethylene glycol, glycerin, dimethyl sulfoxide, lithium chloride, sodium chloride, calcium chloride and the like. Of these, considering the solubility of the emulsifier and the dispersion stabilizer such as a vinyl alcohol polymer and the effect on the stability of the emulsion, as well as the post-treatment after polymerization and the saponification reaction of the vinyl ester polymer, methanol, Dimethyl sulfoxide is most preferred. Although the amount of the freezing point depressant varies depending on the polymerization temperature, the ratio of (water / freezing point depressant) is 10% by weight.
0/0 to 50/50 are preferable, and 10/50 is more preferable.
0/0 to 60/40.

The amount of vinyl ester used is 100
It is 0.5 to 20 parts by weight with respect to parts by weight, preferably 1.
0 to 10 parts by weight, particularly preferably 1.0 to 6.0 parts by weight. When the amount of the vinyl ester used is less than 0.5 parts by weight, the average degree of polymerization of the resulting vinyl ester polymer emulsion is only a few hundred at most, and the desired high degree of polymerization of the vinyl ester polymer cannot be obtained. I can't. When the amount of the vinyl ester exceeds 20 parts by weight, a vinyl ester polymer emulsion having a small particle size and a large number of particles, which is very suitable for a seed emulsion for seed polymerization of vinyl ester, cannot be obtained.

The dispersion stabilizer used in the emulsion polymerization is not particularly limited as long as it is a water-soluble dispersion stabilizer. Among them, an emulsifier or a vinyl alcohol polymer is preferable. As a dispersion stabilizer, a temperature of -60 to
Range of 40 ° C. and a ratio of (water / freezing point depressant) of 10
It is preferable to dissolve under the conditions of 0/0 to 50/50, stabilize the resulting emulsion, and maintain the emulsion state.

Emulsifiers satisfying these requirements include:
Nonionic emulsifiers, nonionic-anionic emulsifiers and anionic emulsifiers can be suitably used. Examples of the nonionic emulsifier include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl ester, and polyoxyethylene sorbitan alkyl ester. Examples of the nonionic anionic emulsifier include polyoxyethylene alkyl phenyl ether sulfate, polyoxyethylene alkyl ether sulfate, and polyoxyethylene alkyl ether phosphate. Examples of the anionic emulsifier include higher alcohol sulfates, alkyl allyl sulfonates, and fatty alcohol phosphates. The above emulsifiers are used alone or in combination. The amount of the emulsifier added to the polymerization system varies depending on the amount of the vinyl ester used, but the amount of the emulsifier (W ₁ ) preferably satisfies the following formula.

[0018]

(Equation 1)

Mw: molecular weight of emulsifier A ₁ : total surface area of particles in emulsion Am: area occupied by molecule of emulsifier Further, B ₁ = [(Mw) × (A ₁ )] / ([Am) × 10
0], the amount of emulsifier used (W ₁ ) is (10 ×
B ₁₎ which preferably ~ (500 × B _1), further preferably _{(10 × B 1) ~ (} 300 × B 1), particularly preferably _{(15 × B 1) ~ (} 250 × B 1) is there.
If the amount of the emulsifier used is less than (10 × B ₁ ), it becomes difficult to keep the particles of the vinyl ester polymer in the emulsion stable, and the particles of the polymer may aggregate. When the amount of the emulsifier used is more than (500 × B ₁ ), the obtained vinyl ester polymer emulsion is used in the seed polymerization of the vinyl ester used in the seed emulsion, and the vinyl ester is converted to the vinyl ester polymer of the seed emulsion. Even after swelling the particles, the emulsifier may become excessive and form new particles.

On the other hand, the vinyl alcohol-based polymer used as the dispersion stabilizer is not particularly limited, and polyvinyl alcohol consisting solely of vinyl alcohol, a copolymer having a vinyl alcohol unit, and a block polymer containing polyvinyl alcohol as one component are used. Coalescence and the like can also be used. The degree of saponification of the vinyl alcohol-based polymer is usually 40 to 100 mol%, preferably 60 to 100 mol%. The average degree of polymerization of the vinyl alcohol polymer is not particularly limited, but is preferably 50 to 30,000,
00 to 20000 is more preferable from the viewpoint of easy availability. The above vinyl alcohol polymers are used alone or in combination. The amount of the vinyl alcohol polymer added to the polymerization system varies depending on the amount of the vinyl ester used, but is generally 0.1 to 10 parts by weight, preferably 0.2 to 6 parts by weight, per 100 parts by weight of the dispersion medium. Part, particularly preferably
0.3 to 4 parts by weight. If the amount of the vinyl alcohol-based polymer is less than 0.1 part by weight, it becomes difficult to stably maintain the particles of the vinyl ester-based polymer in the emulsion, and the polymer particles may aggregate. When the amount of the vinyl alcohol-based polymer exceeds 10 parts by weight, in the vinyl ester seed polymerization using the obtained vinyl ester-based polymer emulsion for the seed emulsion, the vinyl ester is used as the seed emulsion vinyl ester-based polymer. Even after the particles are swollen, the amount of the vinyl alcohol-based polymer becomes excessive and new particles may be formed.

As the initiator used in the emulsion polymerization, a water-soluble redox-based initiator which generates radicals effectively at a low temperature is most effectively used. The water-soluble redox initiator used here is (a) hydroperoxide,
At least one oxidizing substance selected from peroxides or peresters, (b) a metal ion capable of undergoing one electron transfer, and (c) a reducing substance,
Used in combination of components (a) and (b) or a combination of components (a), (b) and (c). Specifically, the oxidizing substance as the component (a) includes hydrogen peroxide, cumene hydroperoxide, t-butyl hydroperoxide, persulfate (K, Na or ammonium salt), t-butyl peracetate, T-butyl perbenzoate is mentioned, and as the metal ion as the component (b), Fe ²⁺ , Cr ²⁺ , V ²⁺ , Ti ³⁺ ,
Co ²⁺ and Cu ⁺ are mentioned, and as the reducing substance as the component (c), Rongalit, l-ascorbic acid and the like are mentioned. Among them, hydrogen peroxide, persulfate (K, Na or ammonium salt), cumene hydroperoxide as component (a), Fe ²⁺ as component (b) and Rongalite as component (c) are most preferred. Used in

In using these initiators, it is necessary to use the initiator so that the component (b) or the sum of the components (b) and (c) is always present in a sufficient excess during the polymerization. Is preferred from the viewpoint of adjusting the polymerization rate and the polymerization rate, but the amounts of the components (a), (b) and (c) are not particularly limited.

The emulsion polymerization of a vinyl ester polymer emulsion at a low temperature as described above has a lower radical concentration than that of a normal emulsion polymerization at a high temperature. They are susceptible and require extra care regarding their removal from the polymerization system prior to polymerization and their intrusion into the polymerization system during polymerization. For this reason, the water, freezing point depressant and vinyl ester used here are all used after sufficient deoxygenation, and the purity in the system is 99.9% or more, preferably 99.99% or more.
% Or more of nitrogen or argon gas. It is preferred that the vinyl esters be purified by a conventional method before use.

The vinyl esters used in the above method include vinyl formate, vinyl acetate, vinyl propionate, vinyl valerate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl benzoate, vinyl pivalate and versatic acid. Vinyl and the like are mentioned, and when a vinyl alcohol polymer is finally obtained, vinyl acetate is particularly preferable.

It is also possible to copolymerize the above-mentioned monomers copolymerizable with the vinyl ester. Examples of these monomers include olefins such as ethylene, propylene, 1-butene and isobutene, acrylic acid and salts thereof, Methyl acrylate, ethyl acrylate, n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, i-butyl acrylate, t-acrylate
Acrylates such as butyl, 2-ethylhexyl acrylate, dodecyl acrylate, octadecyl acrylate, methacrylic acid and its salts, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate;
I-propyl methacrylate, n-butyl methacrylate,
Methacrylates such as i-butyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, dodecyl methacrylate, octadecyl methacrylate, acrylamide, N-methylacrylamide, N
Acrylamide derivatives such as -ethylacrylamide, N, N-dimethylacrylamide, diacetoneacrylamide, acrylamidepropanesulfonic acid and its salts, acrylamidopropyldimethylamine and its salts or quaternary salts, N-methylol methacrylamide and its derivatives, methacryl Amide, N-methylmethacrylamide, N-ethylmethacrylamide, methacrylamidopropanesulfonic acid and its salt, methacrylamidopropyldimethylamine and its salt or 4
Grade salts, methacrylamide derivatives such as N-methylol methacrylamide and derivatives thereof, 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 , Vinyl ethers such as stearyl vinyl ether, nitriles 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, and maleic acid And its salts or esters, itaconic acid and its salts or esters, vinylsilyl compounds such as vinyltrimethoxysilane, and isopropenyl acetate.

The polymerization rate in the above emulsion polymerization is important because it affects the degree of polymerization, and is usually 5% to 90%, preferably 10% to 70%, and more preferably 20% to 60%.
%. Although the polymerization time is not particularly limited, it is not preferable from the viewpoint of operation that it takes more than 5 hours.

Further, the average particle size and the number of particles of the vinyl ester polymer in the emulsion obtained by the low-temperature emulsion polymerization described above were determined by using the vinyl ester polymer emulsion as a seed emulsion to convert the vinyl ester into a seed polymer. This is important because it greatly affects the degree of polymerization of the vinyl ester-based polymer or vinyl alcohol-based polymer obtained. The average particle size of the vinyl ester polymer particles in the vinyl ester polymer emulsion is preferably from 0.005 to 0.5 μm. When an emulsifier is used as the dispersion stabilizer, the average particle size of the vinyl ester polymer particles is preferably from 0.005 to 0.3 μm, and more preferably from 0.01 to 0.25 μm. Emulsions having an average particle size smaller than 0.005 μm can be produced by using a large excess of an emulsifier, but the use of an excess of an emulsifier is not preferable because the purpose cannot be achieved. On the other hand, if the average particle size is larger than 0.3 μm, the number of particles is decreased and the particles of the vinyl ester polymer are enlarged in seed polymerization, which is not preferable. When the dispersion stabilizer is a vinyl alcohol-based polymer, the average particle size of the vinyl ester-based polymer particles is preferably 0.01 to 0.5 μm, and more preferably 0.02 to 0.3 μm. Average particle size is 0.0
Emulsions smaller than 1 μm can be produced by using a large excess of a vinyl alcohol-based polymer, but the use of an excess of a vinyl alcohol-based polymer is not preferred because the purpose cannot be achieved. On the other hand, if the average particle diameter is larger than 0.5 μm, the number of particles is decreased and the particles of the vinyl ester polymer are enlarged in the seed polymerization, which is not preferable.

The number of vinyl ester polymer particles per unit volume (1 milliliter) of the obtained vinyl ester polymer emulsion is preferably 10 ¹² to 10 ¹⁶ , more preferably 10 ^{13 to} 5 × 10 ^15. It is. If the number of particles is less than 10 ¹² particles / milliliter, it is not preferable because new particles are formed during seed polymerization or the polymerization rate is reduced. According to the above method,
A vinyl ester polymer emulsion having a small particle size and a large number of particles per unit volume, which is very suitable for a seed emulsion in the seed polymerization of a vinyl ester, which cannot be obtained by a conventional method, can be obtained.

The vinyl ester polymer emulsion obtained here can be used as it is as a vinyl ester polymer emulsion. However, the production of a high polymerization degree vinyl ester polymer and a high polymerization degree vinyl alcohol polymer can be carried out. When used as a seed emulsion in the seed polymerization of vinyl ester, its characteristics are fully exhibited.

Next, vinyl ester based on seed polymerization
The method for producing the polymer will be described. The vinyl esthetic of the present invention
The method for producing a vinyl polymer is a vinyl ester polymer emulsion.
Using the reaction solution for the seed emulsion
The amount of water-soluble initiator charged per volume (1 liter) is 1 × 1
0^-8~ 2 × 10^-FourMolar and in the seed emulsion
Water-soluble initiator per vinyl ester polymer particle
The charge amount is 1 × 10 ^-28~ 1 × 10^-20Vini in mole conditions
The method is characterized in that the ester is subjected to seed polymerization. seed
Vinyl ester polymer used as emulsion
There is no particular limitation on the emulsion, but the method described above is used.
Vinyl ester polymer emulsion obtained in
Among them, vinyl alcohol-based dispersion stabilizers
Vinyl ester polymer emulsion obtained using polymer
Is more preferred.

In the seed polymerization of the present invention, a vinyl ester, water, a freezing point depressant, the above-mentioned components (b) and (c) and a dispersion stabilizer are added to the seed emulsion as required. The vinyl ester to be added may be the same as or different from that used during the production of the seed emulsion. In addition, the types thereof include the vinyl esters mentioned in the description of the vinyl ester-based polymer emulsion. Among them, vinyl acetate is particularly preferable when a vinyl alcohol polymer is obtained. Further, there is no problem in copolymerizing a monomer copolymerizable with the vinyl ester.

The amount of the vinyl ester to be added is based on the total amount of the vinyl ester polymer (A) in the seed emulsion and the vinyl ester (B) before the start of the seed polymerization ((A) + (B)). Of vinyl ester-based polymer (A) [(A) / ((A)
+ (B)) × 100] is 0.01 to 20%,
From the viewpoint of obtaining a vinyl ester polymer having a high degree of polymerization, the amount is preferably 0.05 to 20%, more preferably 0.05 to 10%. If this ratio exceeds 20%, the effect of the vinyl ester polymer in the seed emulsion becomes large, and it becomes difficult to obtain a vinyl ester polymer having a high degree of polymerization.

When the polymerization temperature is set to 0 ° C. or lower, it is necessary to prevent the aqueous phase as a dispersion medium from coagulating. The added freezing point depressant is added. Although the amount of the freezing point depressant varies depending on the polymerization temperature, the ratio of (water / freezing point depressant) is from 100/0 to 50 / by weight.
50 is preferable and 100/0 to 60/40 are more preferable.

The amount of water added is 300% or less, preferably 200% or less, relative to the amount of the seed emulsion. If the amount of water to be added exceeds 300% of the amount of the seed emulsion, the number of particles in the seed emulsion decreases, so that the average polymerization rate during seed polymerization decreases and the obtained vinyl ester-based The degree of polymerization of the polymer is undesirably low.

The dispersion stabilizer used in the seed polymerization is not particularly limited as long as it is a water-soluble dispersion stabilizer.
Among them, emulsifiers and vinyl alcohol polymers are preferred. Among these dispersion stabilizers, temperature -60
A dispersion stabilizer capable of dissolving under the conditions of 100 to 0/50/50 and a ratio (weight ratio) of (water / freezing point depressant) of 100/0 to 50/50, stabilizing the seed emulsion and maintaining the emulsion state. Is particularly preferred. Among the dispersion stabilizers, as the emulsifier, the nonionic emulsifier, the nonionic-anionic emulsifier and the anionic emulsifier described in the description of the method for producing the vinyl ester polymer emulsion are used. The amount of the emulsifier used is optionally set so that the ratio of the area occupied by adsorption of the emulsifier to the total surface area of the vinyl ester polymer particles in the emulsion before the seed polymerization falls within the range of 10 to 200%. It is preferable to select one. In the seed polymerization of the present invention, it is preferable that the used amount (W ₂ ) of the emulsifier satisfies the following expression.

[0036]

(Equation 2)

Mw: molecular weight of emulsifier A ₂ : total surface area of particles in the emulsion Am: molecular occupied area of emulsifier Further, B ₂ = [(Mw) × (A ₂ )] / [(Am) × 10
0], the amount of the emulsifier used (W ₂ ) is (10 × B ₂ )
To (200 × B ₂ ), more preferably (20 × B ₂ ) to (150 × B ₂ ), and it is particularly preferable to continuously add an emulsifier to the polymerization system during seed polymerization. . The emulsifier may be added intermittently as long as the amount of the emulsifier in the emulsion is within the above range. If the amount of the emulsifier is less than (10 × B ₂ ), the stability of the emulsion is lost and a vinyl ester polymer having a high degree of polymerization cannot be obtained. The amount of emulsifier used is (200 × B
If the amount is larger than ₂ ), the emulsifier is excessively present in the polymerization system, and new particles are formed, which is not preferable for producing a vinyl ester polymer having a high polymerization degree.

As the vinyl alcohol-based polymer among the dispersion stabilizers, the vinyl alcohol-based polymer mentioned in the description of the method for producing the vinyl ester-based polymer emulsion is used. The amount of the vinyl alcohol-based polymer added to the polymerization system varies depending on the amount of the vinyl ester used, but is usually 0.5 to 30 parts by weight, preferably 0.5 to 20 parts by weight, per 100 parts by weight of the dispersion medium. Parts by weight, more preferably 1.0 to 10 parts by weight. In adding the vinyl alcohol-based polymer, it is particularly preferable to continuously add the vinyl alcohol-based polymer to the polymerization system during seed polymerization. The vinyl alcohol polymer may be added intermittently if the amount of the vinyl alcohol polymer in the emulsion is within the above range. When the amount of the vinyl alcohol-based polymer is less than 0.5 parts by weight, it is difficult to stably maintain the particles of the vinyl ester-based polymer in the emulsion, and aggregation of the polymer particles may occur. As a result, a vinyl ester polymer having a high degree of polymerization cannot be obtained. If the amount of the vinyl alcohol-based polymer is more than 30 parts by weight, the viscosity of the polymerization system may be too high, so that the polymerization cannot proceed uniformly or the heat of polymerization cannot be removed. This is not sufficient for producing a vinyl ester polymer having a high degree of polymerization because it is sufficient and new particles are formed.

The order of addition of the vinyl ester, water, freezing point depressant, component (b), component (c) and dispersion stabilizer to be added to the seed emulsion is arbitrary as long as the seed emulsion is kept stable. The seed polymerization temperature is -60 to 6 to obtain a vinyl ester polymer having a high polymerization degree.
0 ° C, preferably -60 to 40 ° C, more preferably -5.
0 to 40 ° C, more preferably −40 to 40 ° C., still more preferably −30 to 40 ° C., and still more preferably −30 to 40 ° C.
30 ° C. When the polymerization temperature is set to 0 ° C. or lower, a freezing point depressant is required for the purpose of preventing coagulation as described above.

Next, the water-soluble initiator used in the seed polymerization will be described. Redox initiators are preferably used as the water-soluble initiator. As the redox initiator, the water-soluble redox initiator composed of the components (a), (b) and (c) described in the description of the method for producing the vinyl ester polymer emulsion is used. The charged amount of the water-soluble initiator per unit volume (1 liter) is 1 × 10 ⁻⁸ to 2 × 10 ⁻⁴ mol, and the vinyl ester polymer particles 1 in the seed emulsion
The amount of the water-soluble initiator charged per unit is 1 × 10 ⁻²⁸ to 1 × 1
It needs to be ^0-20 moles.

In the present invention, vinyl acetate is used as an initiator.
When describing the manufacturing method of the ester polymer emulsion.
Redo consisting of components (a), (b) and (c)
When using a water-based initiator, the amount of water-soluble initiator
Means the amount of component (a) (ie, oxidizing substance) charged
I do. Water solubility per unit volume (1 liter) of charged reaction solution
The amount of the initiator charged is 1.0 × 10 ^-8~ 2 × 10^-FourIs a mole
And more preferably 5 × 10^-8~ 1 × 1
0^-FourMol, more preferably 1 × 10^-7~ 1 × 10^-FourMo
It is. The amount of the water-soluble initiator charged is 1.0 × 10^-8Mol /
If less than 1 liter, the polymerization rate will
The advantage of John polymerization is impaired and 2 × 10^-FourMole
Per liter, the seed emulsion particles
Numerous radicals are present in the derived emulsion particles
And a high degree of polymerization of vinyl ester polymer and
And a vinyl alcohol polymer cannot be obtained. Also,
1 vinyl ester polymer particles in the emulsion
The amount of the water-soluble initiator charged per 1 × 10^-28~ 1 × 1
0^-20Moles, preferably 1 × 1
0^-27~ 5 × 10^{-twenty one}Moles, more preferably 5 × 10
^-27~ 1 × 10^{-twenty one}Is a mole.

The water-soluble initiator will be described in more detail. The rate of radical generation and the like differ depending on the type of the initiator used, but it is a redox-based initiator composed of the components (a), (b) and (c). When is used, the radical is generated by the addition of the component (a), and the rate of disappearance of the radical varies depending on the polymerization temperature and the vinyl ester monomer in the vinyl ester polymer particles. In the seed polymerization of the present invention, the number of radicals Y per unit time (second) per vinyl ester-based polymer particle in the seed emulsion represented by the following formula is 6 × 10
^{-7 to} 0.12 is advantageous for obtaining a vinyl ester polymer and a vinyl alcohol polymer having a high degree of polymerization, and is preferably 3 × 10 ^{-7 to} 0.12, and more preferably 6 × 10 ^{-7 to} 0.12.
10 ^{-6 to} 0.12 is more preferred. Y = 6.0 × 10 ²⁰ × [(a)] / N (where [(a)] is the amount of the water-soluble initiator charged per unit time per unit volume (1 liter) of the charged reaction liquid (mol / mol). Liters / second), and N represents the number of vinyl ester-based polymer particles (units / milliliter) per unit volume of the seed emulsion (1 milliliter).)

In using these redox initiators, it is necessary to ensure that the component (b) or the sum of the components (b) and (c) is present in a sufficient excess during the polymerization. It is important to use it, if not,
After the polymerization, the component (a) remains in the polymerization system, and when the temperature of the system is increased in steps such as post-treatment, an undesired post-polymerization reaction occurs, and as a result, the high polymerization degree which is the object of the present invention is obtained. You won't get anything.

In consideration of such points, when the components (a), (b) and (c) are added to the polymerization system, the component (b) or the components (b) and (c) are entirely seed-polymerized. It is preferable to use a method in which (a) is delayed and added from the beginning. As a method of adding the components (b) and (c), there are a method of adding a large amount of the components (b) and (c) in advance when producing a seed emulsion, and a method of adding the components at the start of seed polymerization. Can be adopted in the present invention.

The mutual concentration ratio and addition method of the components (a), (b) and (c) are the same as in the production of the seed emulsion, and the degree of polymerization of the vinyl ester polymer or vinyl alcohol polymer is the same. Is a factor that greatly affects the

Since the seed polymerization of the present invention is carried out at a low temperature, as in the case of the production of the seed emulsion, it is necessary to pay sufficient attention to the removal of oxygen from the system and the intrusion of oxygen into the polymerization system during the polymerization. is there.

The present invention provides a method for obtaining a vinyl ester polymer and a vinyl alcohol polymer having a high degree of polymerization. The rate of polymerization in seed polymerization of the present invention is important because it affects the degree of polymerization. Yes, usually 10-95
%, Preferably 20 to 90%, more preferably 30 to 90%.
85%. The polymerization time is not particularly limited, but is preferably 1 to 15 hours. The average polymerization rate is also important because it affects the degree of polymerization, and the average polymerization rate varies depending on the number of particles in the emulsion, but is preferably 2 to 25% / hr, more preferably 3 to 20% / hr.

Further, the number of particles of the vinyl ester polymer during and after seed polymerization is also important because it affects the degree of polymerization and the polymerization rate, and the number of particles per unit volume (1 ml) of the seed emulsion is as follows. , 10
⁸ to 10 ¹⁶ are preferred. When the dispersion stabilizer is an emulsifier, it is preferably 10 ¹² to 10 ¹⁶ particles / ml, and
¹³ to 5 × 10 ¹⁵ cells / ml is more preferred. When the dispersion stabilizer is a vinyl alcohol polymer, 10 ⁸
10 to 10 ¹⁵ cells / ml, preferably 10 ^{10 to} 5 × 1
0 ¹⁴ cells / ml is more preferable. 10 ¹² particles
Number / ml in the case (when the dispersion stabilizer of emulsifier) or 10 ⁸ particles / ml (dispersion stabilizer may vinyl alcohol polymer) less than the polymerization rate becomes extremely small, the emulsion polymerization The benefits will be lost. The average particle size of the vinyl ester-based polymer particles is particularly limited because it depends on the average particle size of the seed emulsion used, since the intention of the present invention is to grow the seed emulsion as it is without agglomeration. However, it is preferably 10 μm or less, more preferably 5 μm or less.

According to the present invention, a vinyl ester polymer having an average degree of polymerization of 4000 or more, preferably 7000 or more can be easily produced as compared with the conventional method.
Here, the average degree of polymerization of the vinyl ester polymer is obtained from the intrinsic viscosity [η] of polyvinyl acetate obtained by saponifying the vinyl ester polymer and re-acetylating the polyvinyl acetate at 30 ° C. in acetone. It is represented by the determined viscosity average degree of polymerization (P). P = ([η] × 10 ³ /7.94) ^{(1 / 0.62)}

Although the description so far mainly relates to the case where the seed polymerization is batch polymerization, the seed polymerization of the vinyl ester of the present invention is not limited to batch polymerization but can be applied to continuous polymerization. Assuming industrial production, the seed polymerization of the vinyl ester of the present invention is preferably continuous polymerization rather than batch polymerization.

The case where the vinyl ester seed polymerization is carried out by continuous polymerization will be described below. The process of the present invention is a continuous polymerization process, i.e., a continuous feeding of a vinyl ester polymer seed emulsion, a vinyl ester monomer, water, an emulsifier, a protective colloid, an initiator, a freezing point depressant and optionally other polymerization aids to a reactor. It can be carried out by introducing an agent and continuously removing the polymerization emulsion. By performing this continuous polymerization operation, it is possible to reduce the size of the apparatus, stabilize the quality, and reduce the adhesion of scale and the like. In this case, regardless of whether the reactor is a stirred reactor, a tubular reactor, or a reactor in which both are combined, it is possible to rapidly and completely mix substances continuously added. As far as is possible, various known devices can be used. In this case, for example, one or more continuously connected stirred reactors, loop tube reactors,
A multi-chamber sectional reactor can be used.

In the case of continuously producing a seed emulsion, the same procedure as described above may be used. For the device,
It may be completely filled with the polymerization reaction solution and have no space, or may have a space formed by nitrogen, argon gas or the like. The seed emulsion, vinyl ester monomer, water, emulsifier, protective colloid, initiator, and freezing point depressant are the same as those in the case of seed polymerization by the batch method described above. The method of adding each component can be added individually, or can be mixed and added in a total amount, and can be uniformly or non-uniformly distributed to the number of reactors and added to each reactor. It is also possible, and there is no particular limitation. Further, the polymerization temperature, the polymerization rate, the polymerization time, and the average polymerization rate may be selected in the same manner as in the seed polymerization by the batch method described above. The average residence time is
The time is 1.0 to 15.0 hours, preferably 2.0 to 10.0 hours, particularly preferably 2.0 to 8.0 hours.

Finally, a method for producing a vinyl alcohol-based polymer will be described. The vinyl ester-based polymer emulsion obtained by the seed polymerization of the present invention can naturally precipitate and recover the polymer by ordinary coagulation or stripping, but when a vinyl alcohol-based polymer is obtained, The vinyl ester polymer emulsion thus obtained is dissolved in a large amount of methanol or dimethyl sulfoxide containing an inhibitor, and the unreacted vinyl ester is removed by distillation to obtain a methanol solution or a dimethyl sulfoxide solution of the vinyl ester polymer. Is preferred. These solutions contain water, but are subject to alcoholysis using sodium hydroxide, sodium methylate or sodium ethylate as a catalyst, or sulfuric acid,
A vinyl alcohol polymer can be obtained by a saponification reaction by acid decomposition using an acid such as hydrochloric acid or phosphoric acid as a catalyst. The amount of the alkali catalyst or the acid catalyst used in the saponification reaction and the temperature of the saponification reaction are not particularly limited, and the saponification reaction can be performed in the same manner as in the conventional method.

Since the vinyl alcohol polymer obtained in the present invention has a high degree of polymerization, if it is a completely saponified product, it can be washed with cold water and can remove impurities such as sodium acetate, an emulsifier and an initiator. Further, washing with an aqueous acid solution is effective for removing metal ions. According to the method of the present invention, a vinyl alcohol-based polymer having an average degree of polymerization of 4000 or more, preferably 7000 or more can be produced more easily than the conventional method. Here, the average degree of polymerization of the vinyl alcohol-based polymer is the viscosity obtained from the intrinsic viscosity [η] measured at 30 ° C. in acetone for polyvinyl acetate obtained by re-acetylating the vinyl alcohol-based polymer according to the following equation. It is represented by the average degree of polymerization (P). P = ([η] × 10 ³ /7.94) ^{(1 / 0.62)}

【Example】

Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited thereto. In the examples, "%" and "part" represent "% by weight" and "part by weight", respectively, unless otherwise specified. The average particle size of the polymer emulsion was measured using a submicron particle analyzer NICOMP Mod
The measurement was performed using el 370 (manufactured by Hiac / Royco). The number of particles per unit volume was calculated from the measured average particle size and the conversion by the following formula. Number of particles (pieces / milliliter) = 3Mx / 4πr ³ d where M is the amount of monomer (g), x is the conversion from monomer to polymer, and r is the average particle size of the emulsion (c
m) and d represent the specific gravity of the emulsion, respectively. As the molecular occupation area of the emulsifier, a value obtained by an experiment from a soap titration method was used for each medium to be used.

Example 1 1000 parts of ion-exchanged water, 30 parts of vinyl acetate, polyoxyethylene [POE (40)] nonylphenyl ether (Nonipol 400, 3.0 parts, manufactured by Sanyo Chemical Co., Ltd.
Rongalite 0.60 parts of FeSO ₄ · 7H ₂ O 0.
After adding 03 parts and boiling for 30 minutes, the mixture was cooled to 5 ° C. while introducing nitrogen, and a 0.024% hydrogen peroxide solution prepared using separately degassed ion-exchanged water was uniformly mixed at 10 parts / hr. The polymerization was started while continuously adding the mixture. During the polymerization, the system was sealed with nitrogen gas to prevent oxygen from entering. After 0.2 hours, the polymerization solution turned blue, and after 0.5 hours, the conversion was 47.8.
%, Stop adding hydrogen peroxide, and then
When stirring was continued for 0.5 hour, the polymerization rate was 56.9%. When the average particle size of the obtained emulsion was measured, it was 0.047 μm. Further, the number of particles of polyvinyl acetate per unit volume of the emulsion was calculated using the value of the average particle diameter thus obtained, to be 2.6 × 10 ¹⁴ particles / ml, and the used amount (W ₁ ) of the emulsifier was 3.0 parts. It can be expressed by the following equation. (W ₁ ) = [(Mw × A ₁ ) / (Am × 100)] × 163 Mw: molecular weight of emulsifier A ₁ : total surface area of particles in emulsion Am: molecular occupation area of emulsifier

Separately, after boiling for 30 minutes, 970 parts of vinyl acetate cooled to 5 ° C. while introducing nitrogen was added to the emulsion obtained above and adjusted to 5 ° C. 0.010% hydrogen peroxide solution prepared using separately degassed ion-exchanged water was added at a rate of 10 parts / hr, and a 22% nonipol 400 aqueous solution prepared by adding separately degassed ion-exchanged water Was continuously added at a rate of 10 parts / hr. During polymerization, seal the system with nitrogen gas,
Oxygen was suppressed. After 4.5 hours, 59.6% conversion
(When the maximum polymerization rate reached 17% / hr), the addition of the aqueous solution of hydrogen peroxide and Nonipol 400 was stopped to stop the polymerization. When the average particle size of the obtained emulsion was measured, it was 0.26 μm. The number of polyvinyl acetate particles per unit volume of the emulsion was 5.2 × 10 ¹³
The unit / milliliter and the amount of the emulsifier used (W ₂ ) 45 parts can be represented by the following formula. (W ₂ ) = [(Mw × A ₂ ) / (Am × 100 × 0.22)]
× 111 Mw: molecular weight of emulsifier A ₂ : total surface area of particles in emulsion Am: molecular occupation area of emulsifier

The emulsion thus obtained was added to a solution of 1 part of hydroquinone monomethyl ether in 70,000 parts of methanol at room temperature and dissolved with stirring.
After dissolution, unreacted vinyl acetate was removed while adding methanol under reduced pressure to obtain a methanol solution of polyvinyl acetate. A part of this solution is taken and the concentration is 6%, [NaOH]
/ [VAc] (molar ratio) = 0.1 and saponification at a temperature of 40 ° C, and 0.1 part of the obtained polyvinyl alcohol is mixed with a mixture of 8 parts of acetic anhydride and 2 parts of pyridine at 105 ° C for 20 hours.
The polyvinyl acetate obtained by re-acetylation with occasional stirring and repeated reprecipitation purification with acetone-ether and acetone-water was found to have a viscosity-average degree of polymerization of 22,600 determined from the intrinsic viscosity measured at 30 ° C. in acetone. there were.

Next, a methanol solution of polyvinyl acetate was
Concentration 6%, [NaOH] / [VAc] (molar ratio) = 0.1
After saponification at 5 and a temperature of 40 ° C., the obtained polyvinyl alcohol was drained, and the same amount of NaOH as that used for saponification was added.
Re-saponified for 4 hours. Then neutralize with 1N sulfuric acid, 0.00
Washing with 01N sulfuric acid and further washing with ion-exchanged water were repeated, finally washing with methanol, draining and drying at 40 ° C. to obtain purified polyvinyl alcohol. This polyvinyl alcohol has a degree of saponification of 99.8 mol%, and the polyvinyl alcohol obtained by re-acetylating the polyvinyl alcohol under the same conditions as described above and repeating reprecipitation and purification in the same manner as described above was treated in acetone at 30 ° C. The viscosity average degree of polymerization determined from the measured intrinsic viscosity was 22,600.

In the above-mentioned seed polymerization, the charged amount A (mol / liter) of the water-soluble initiator (here, hydrogen peroxide) per unit volume (1 liter) of the charged reaction solution is 6.
A 15 × 10 ^-5, (in this case, hydrogen peroxide) vinyl ester polymer particles per water soluble initiator in the seed emulsion charged amount of B (mol / number) is 2.36 × 1
It was ^0-22 . Also, the amount C (mol / liter.multidot.liter) of the water-soluble initiator (here, hydrogen peroxide) per unit time (second) per unit volume (1 liter) of the charged reaction liquid.
Sec) was 3.79 × 10 ⁻⁹ , and the Y value defined by the following equation was 8.76 × 10 ⁻³ . Y value = (6.0 × 10 ²⁰ × prepared amount C) / N N: Number of particles of vinyl ester polymer per unit volume (1 ml) of seed emulsion (pieces / milliliter) Charge amount C: As described above, Amount of water-soluble initiator charged per unit time (second) per unit volume (1 liter) of charged reaction liquid (mol / liter-second)

Comparative Example 1 1000 parts of ion-exchanged water, 1000 parts of vinyl acetate, and polyoxyethylene [POE (4
0)] nonylphenyl ether (Nonipol 400, Sanyo Kasei Co., Ltd.) 30 parts were charged 1.25 parts of Rongalite and FeSO ₄ · 7H ₂ O 0.12 parts, after boiling for 30 minutes, while introducing nitrogen 5 The mixture was cooled to 0 ° C., and polymerization was started while uniformly adding 0.075% aqueous hydrogen peroxide prepared by using degassed ion-exchanged water at a rate of 10 parts / hr. During the polymerization, the system was sealed with nitrogen gas in the same manner as in Example 1 to suppress the invasion of oxygen. After 3.5 hours, when the polymerization rate reached 60.2% (maximum polymerization rate: 17.2% / hr), the addition of the hydrogen peroxide solution was stopped, and the polymerization was stopped. When the average particle size of the obtained emulsion was measured
0.228 μm, and the number of polyvinyl acetate particles per unit volume of the emulsion was 4.2 × 10 ¹³ particles / ml. The used amount (W ₁ ) of the used emulsifier was 30 parts by the following formula. (W ₁ ) = [(Mw × A ₁ ) / (Am × 100)] × 275 Mw, A ₁ and Am are the same as above.

The emulsion thus obtained was added to a solution of 1 part of hydroquinone monomethyl ether in 25,000 parts of methanol at room temperature, and dissolved with stirring. After dissolution, unreacted vinyl acetate was removed in the same manner as in Example 1 to obtain a methanol solution of polyvinyl acetate. A portion of this solution was subjected to a saponification reaction and a re-acetylation reaction under the same conditions as in Example 1 to obtain purified polyvinyl acetate. The viscosity-average degree of polymerization of the polyvinyl acetate determined from the intrinsic viscosity measured at 30 ° C. in acetone was 14,
000.

Next, the methanol solution of polyvinyl acetate was saponified, re-saponified, neutralized, washed and dried under the same conditions as in Example 1 to obtain purified polyvinyl alcohol.
This polyvinyl alcohol has a degree of saponification of 99.9 mol%, and the polyvinyl alcohol obtained by re-acetylating the polyvinyl alcohol under the same conditions as described above and repeating reprecipitation and purification in the same manner as described above was treated in acetone with 30% The viscosity average degree of polymerization determined from the intrinsic viscosity measured at ° C. was 14,000.

As described above, despite the fact that the emulsion polymerization was carried out under almost the same polymerization conditions, the viscosity average degree of polymerization was 14,000 in the 5 ° C. emulsion polymerization shown in Comparative Example 1.
On the other hand, in the seed polymerization at 5 ° C. of the present invention shown in Example 1, the viscosity average degree of polymerization is 22,600, so that polyvinyl acetate and polyvinyl alcohol having a very high degree of polymerization can be easily obtained. You can see that.

Example 2 In the same reactor as in Example 1, 1000 parts of ion-exchanged water, 100 parts of vinyl acetate, and polyoxyethylene [POE (3
5)] 12.5 parts of an 80% aqueous solution of sodium nonylphenyl ether sulfate (Eleminol ES-70M, manufactured by Sanyo Chemical Co., Ltd.), 0.40 parts of Rongalite, and FeSO _4.
After 0.02 parts of 7H ₂ O were charged and boiled, the mixture was cooled to 40 ° C. and prepared using ion-exchanged water which had been separately degassed.
The polymerization was started while uniformly and continuously adding an 08% aqueous potassium persulfate solution at 5 parts / hr. When the polymerization rate reached 30.6% after 0.2 hours, the addition of the aqueous potassium persulfate solution was stopped, and the mixture was further stirred at 40 ° C. for 0.8 hours. The polymerization rate was 68.2%. The average particle size of the obtained emulsion was 0.097 μm, the number of polyvinyl acetate particles per unit volume of the emulsion was 1.2 × 10 ¹⁴ particles / milliliter, and the amount of the emulsifier used (W ₁ ) was 12.5 parts. Can be expressed by the following equation. (W ₁ ) = [(Mw × A ₁ ) / (Am × 100 × 0.80)]
× 462 Mw, A ₁ and Am are the same as above.

Separately, 900 parts of boiled and degassed vinyl acetate was added to the emulsion obtained above and adjusted to 40 ° C. Thereafter, the polymerization was started while uniformly and continuously adding the aqueous potassium persulfate solution used previously at 5 parts / hr and the aqueous 18% eleminol ES-70 aqueous solution having a concentration of 18% separately degassed under reduced pressure at 12 parts / hr. 3.0 hours after polymerization rate 7
When 8.9% (maximum polymerization rate 29.3% / hr) was reached, an aqueous solution of potassium persulfate and Eleminol ES-7 were used.
The addition of the 0 aqueous solution was stopped, and the polymerization was stopped. The average particle size of the obtained emulsion is 0.246 μm, and the number of polyvinyl acetate particles per unit volume of the emulsion is 7.7 × 10 ¹³
Per emulsifier and the amount of emulsifier used (W ₂ ) 4
8.5 parts can be expressed by the following formula. (W ₂ ) = [(Mw × A ₂ ) /Am×100×0.18) ×
167 Mw, A ₂ and Am are the same as above.

The emulsion thus obtained was added to a solution of 0.6 part of hydroquinone monomethyl ether in 15000 parts of dimethyl sulfoxide at room temperature and dissolved with stirring. After dissolution, unreacted vinyl acetate was removed at 70 ° C. while adding dimethyl sulfoxide under reduced pressure to obtain a solution of polyvinyl acetate in dimethyl sulfoxide. Take a part of this solution, put it in distilled water, take out polyvinyl acetate once, repeat the reprecipitation purification with acetone-n-hexane several times, then put it in distilled water and boil to obtain purified poly (vinyl acetate). Vinyl acetate was obtained. The polyvinyl acetate was dissolved in methanol, and the concentration was 10%, [NaOH] / [VAc].
(Molar ratio) = Saponification at 0.10 and a temperature of 40 ° C to obtain polyvinyl alcohol. The polyvinyl alcohol was re-acetylated and purified under the same conditions as in Example 1 to obtain polyvinyl acetate. The viscosity average degree of polymerization of the polyvinyl acetate is 5,
000.

Next, a solution of polyvinyl acetate in dimethyl sulfoxide was saponified at a concentration of 10%, [NaOH] / [VAc] (molar ratio) = 0.15 and a temperature of 40 ° C. under a nitrogen flow.
After removing the obtained polyvinyl alcohol, resaponifi- cation, neutralization, washing with water and washing with methanol were carried out in the same manner as in Example 1.
After drying, a purified polyvinyl alcohol was obtained. The polyvinyl alcohol had a degree of saponification of 99.8 mol%. The viscosity-average degree of polymerization of the polyvinyl acetate obtained by repeating the re-acetation and re-precipitation purification in the same manner as above was measured to be 4,950.
Met.

In the above-mentioned seed polymerization, the charged amount A (mol / liter) of the water-soluble initiator (here, potassium persulfate) per unit volume (1 liter) of the charged reaction solution.
Is 2.10 × 10 ⁻⁶ , and the charged amount B (mol / unit) of a water-soluble initiator (here, potassium persulfate) per vinyl ester-based polymer particle in the seed emulsion is 1.
It was 75 × 10 ^-23 . In addition, the unit volume of the charged reaction solution (1
The charged amount C (mol / liter · second) of the water-soluble initiator (here, potassium persulfate) per unit time (second) per liter) is 1.94 × 10 ⁻¹⁰ and is defined as above. The Y value was 9.72 × 10 ⁻⁴ .

Comparative Example 2 1000 parts of ion-exchanged water, 1000 parts of vinyl acetate, and polyoxyethylene [POE (3
5)] nonyl phenyl ether sulfate 80% aqueous solution of 50.0 parts of (ELEMINOL ES-70, Sanyo Kasei Co., Ltd.), Rongalite 0.80 parts of FeSO ₄ · 7
After charging 0.06 parts of H ₂ O and boiling for 30 minutes, the mixture was cooled to 40 ° C. while introducing nitrogen, and 7 parts / water of a 0.025% aqueous potassium persulfate solution prepared with degassed ion-exchanged water was added. The polymerization was started while continuously adding the mixture at a constant rate of hr.
After 3.0 hours, the polymerization rate was 77.8% (the maximum polymerization rate was 29.0% /
Upon reaching hr), the addition of the aqueous potassium persulfate solution was stopped, and the polymerization was stopped. The average particle size of the obtained emulsion was 0.302 μm, and the number of polyvinyl acetate particles per unit volume of the emulsion was 4.4 × 1.
It was ¹³ / ml. The used amount (W ₁ ) of the used emulsifier was 50 parts by the following formula. (W ₁ ) = [(Mw × A ₁ ) / (Am × 100 × 0.80)]
× 522 Mw, A ₁ and Am are the same as above.

The emulsion thus obtained was obtained in the same manner as in Example 2 to obtain a solution of polyvinyl acetate in dimethyl sulfoxide. Further, a portion of this solution was taken out of the purified polyvinyl acetate in the same manner as in Example 2, and then a 10% methanol solution was prepared. Thereafter, saponification, purification, drying, re-acetylation and purification were carried out in the same manner as in Example 1 to obtain purified polyvinyl acetate. The viscosity-average degree of polymerization of the polyvinyl acetate determined from the intrinsic viscosity measured at 30 ° C. in acetone was 3,500.

Next, the dimethyl sulfoxide solution of polyvinyl acetate was saponified, re-saponified, neutralized, washed and dried under the same conditions as in Example 2 to obtain purified polyvinyl alcohol. The degree of saponification of this polyvinyl alcohol was 99.8 mol%, and the polyvinyl alcohol was re-acetylated under the same conditions as described above, and reprecipitation purification was repeated in the same manner as above. The viscosity average degree of polymerization determined from the intrinsic viscosity measured in 3,500
Met.

Comparative Example 3 Polymerization, saponification and purification were carried out in the same manner as in Comparative Example 1 except that the polymerization conditions shown below were changed, and the degree of saponification and viscosity average of the obtained polyvinyl acetate and polyvinyl alcohol were obtained. The degree of polymerization was measured. Only the points where the polymerization conditions were changed are shown below. 40 parts of a 35% aqueous solution of sodium polyoxyethylene [POE (30)] lauryl ether sulfate (trax K-300, manufactured by NOF CORPORATION) as an emulsifier to be charged into the reactor, Rongalit 1.40
Part, FeSO ₄ · 7H ₂ O 0.15 parts of methanol 36
0 parts and the same amounts of ion-exchanged water and vinyl acetate as in Comparative Example 1 were charged, boiled and deaerated, and then cooled to -20 ° C. 0.020
% Of aqueous hydrogen peroxide was continuously added at a rate of 10 parts / hr to initiate polymerization. After 6.0 hours, when the polymerization rate reached 51.2% (maximum polymerization rate 9.1% / hr), the polymerization was stopped. The average particle size of the obtained emulsion is 0.317μ.
m, the number of polyvinyl acetate particles per emulsion unit volume was 1.7 × 10 ¹³ particles / ml. The amount of the emulsifier used (W ₁ ) 40 parts was represented by the following formula. (W ₁ ) = [(Mw × A ₁ ) / (Am × 100 × 0.35)]
× 276 Mw, A ₁ and Am are the same as above.

The emulsion thus obtained was added to a solution of 1 part of hydroquinone monomethyl ether in 70,000 parts of methanol at room temperature and dissolved with stirring.
The viscosity average degree of polymerization of the polyvinyl acetate was 24,000. The polyvinyl alcohol obtained by saponifying the polyvinyl acetate had a saponification degree of 99.8 mol% and a viscosity average polymerization degree of 24,000. Compared with Examples 3, 5 and 7 shown below in which the polymerization temperature is the same, Comparative Example 3, which does not rely on seed polymerization, has a lower degree of polymerization of the obtained polyvinyl acetate and polyvinyl alcohol.

Examples 3 to 10 and Comparative Examples 4 and 5 Except that the production conditions of the seed emulsion shown in Table 1 and the production conditions of the seed polymerization shown in Table 2 were changed,
Polymerization, saponification, purification and the like were performed in the same manner as in Example 1. Table 1 shows the production results of the seed emulsion, and Table 2 shows the results of the seed polymerization. In addition,
The coverage Co in Table ₁ is W ₁ = [(Mw × A ₁ ) / (Am × 100 × An × 0.0).
1)] × Co W ₁ : used amount of emulsifier Mw: molecular weight of emulsifier A ₁ : total surface area of particles in emulsion Am: molecular occupied area of emulsifier An: concentration of emulsifier On the other hand, the coverage Co in Table 2
Is W ₂ = [(Mw × A ₂ ) / (Am × 100 × An × 0.0)
1)] × Co W ₂ : used amount of emulsifier Mw: molecular weight of emulsifier A ₂ : total surface area of particles in latex Am: molecular occupied area of emulsifier An: concentration of emulsifier

[0076]

[Table 1]

[0077]

[Table 2]

[0078]

[Table 3]

[0079]

[Table 4]

[0080]

[Table 5]

[0081]

[Table 6]

[0082]

[Table 7]

[0083]

[Table 8]

[0084]

[Table 9]

[0085]

[Table 10]

Example 11 In the same manner as in Example 1, the emulsion weight was
And then mix the resulting emulsion with a seed emulsion.
Seed polymerization at 25 ° C for 1.5 hours
Rate reached 25.2% (maximum polymerization rate 17% / hr)
And a seed emulsion separately prepared in the same manner as in Example 1.
John 610 parts / hr, vinyl acetate 590 parts / hr, 2
A 10% aqueous solution of 0% Nonipol 400 was added at 10 parts / hr.
010% aqueous hydrogen peroxide is added continuously at a rate of 10 parts / hr.
At the same time, the reaction mixture is continuously added at 1220 parts / hr.
Second reactor with continuous removal and equipped with identical equipment
Was introduced. 20% nonipol 4 in the second reactor
00 aqueous solution at 10 parts / hr and 0.010% aqueous peroxide
Raw water was added continuously at a uniform rate of 10 parts / hr, and the polymerization rate was 50%.
(Polymerization time 1.5 hours), the reaction mixture
Continuous removal at 1240 parts / hr.
Introduced to the reactor. In the third reactor, 20%
10 parts / hr of Nipol 400 aqueous solution and 0.010%
Of hydrogen peroxide solution at a rate of 10 parts / hr.
When the total rate reached 75% (polymerization time 1.5 hours),
The reaction mixture was continuously removed at 1260 parts / hr. Get
The average particle size of the emulsion was measured to be 0.28.
5 μm, and the emulsion unit volume (1 milliliter
Particles of 5.0 × 10 per torr)¹³Pieces
/ Milliliter. In addition, the unit volume of the charged reaction solution (1
Per liter of water-soluble initiator (here, peroxide water)
The amount of raw material A (mol / liter) is 6.2 × 10 ^-Five,
1 vinyl ester polymer particles in the emulsion
Of water-soluble initiator (here, hydrogen peroxide) per unit
The quantity B (mol / piece) is 2.4 × 10^{-twenty two}Mol / piece.

When the obtained emulsion was subjected to saponification and purification in the same manner as in Example 1, the viscosity average degree of polymerization of polyvinyl acetate was 22,000. The polyvinyl alcohol obtained by saponifying the polyvinyl acetate had a saponification degree of 99.8 mol% and a viscosity average polymerization degree of 22,000.
Met.

Example 12 In a reactor equipped with a stirrer, a thermometer, a nitrogen inlet tube and a cooling tube, 1000 parts of ion-exchanged water, 30 parts of vinyl acetate, polyvinyl alcohol (polymerization degree 500, saponification degree 88 mol% (PVA- 205, manufactured by Kuraray Co., Ltd.) 20 parts were charged 0.90 parts of Rongalite and FeSO ₄ · 7H ₂ O 0.05 parts after boiling for 30 minutes, while introducing nitrogen 5
The mixture was cooled to 0 ° C., and polymerization was started while uniformly adding a 0.050% aqueous solution of potassium sulfate, which was prepared using degassed ion-exchanged water, at a rate of 5 parts / hr. During the polymerization, the system was sealed with nitrogen gas to prevent oxygen from entering. After 0.1 hour, the polymerization solution turned blue, and after 0.5 hour, the polymerization rate was 50.1.
%, The addition of the aqueous potassium persulfate solution was stopped to stop the polymerization, and then stirring was continued for 0.5 hour. As a result, the conversion was 52.1%. When the average particle size of the obtained emulsion was measured, it was 0.070 μm. Further calculating the number of particles of polyvinyl acetate per unit volume of the emulsion using the value of the obtained average particle size 7.
It was 3 × 10 ¹³ / ml.

Separately, after boiling for 30 minutes, 970 parts of vinyl acetate cooled to 5 ° C. while introducing nitrogen was added to the emulsion obtained above and adjusted to 5 ° C.
0.050% prepared using separately degassed ion-exchanged water
Of potassium persulfate aqueous solution at 10 parts / hr, and 20% polyvinyl alcohol (polymerization degree 500, saponification degree 88 mol% (P
VA-205, manufactured by Kuraray Co., Ltd.) 15 parts / hour of aqueous solution
The polymerization was started while the mixture was continuously and uniformly added. During polymerization, the system was sealed with nitrogen gas to keep oxygen from entering. After 5.0 hours, when the polymerization rate reached 75.6% (maximum polymerization rate 16% / hr), the addition of the aqueous potassium persulfate solution and the aqueous vinyl alcohol solution was stopped to stop the polymerization. When the average particle size of the obtained emulsion was measured, it was found to be 0.53 μm
Met. The number of polyvinyl acetate particles per unit volume of the emulsion was calculated to be 7.4 × 10 ¹² particles / ml.

The emulsion thus obtained was added to a solution of 1 part of hydroquinone monomethyl ether in 70,000 parts of methanol at room temperature and dissolved with stirring.
After dissolution, unreacted vinyl acetate was removed while adding methanol under reduced pressure to obtain a methanol solution of polyvinyl acetate. A part of this solution is taken and the concentration is 6%, [NaOH]
/ [VAc] (molar ratio) = 0.1 and saponification at a temperature of 40 ° C, and 0.1 part of the obtained polyvinyl alcohol is mixed with a mixture of 8 parts of acetic anhydride and 2 parts of pyridine at 105 ° C for 20 hours.
The polyvinyl acetate obtained by re-acetylation with occasional stirring and re-precipitation purification with acetone-ether and acetone-water systems was found to have a viscosity-average degree of polymerization of 22,800 determined from the intrinsic viscosity measured at 30 ° C. in acetone. Was.

Next, a methanol solution of polyvinyl acetate was
Concentration 6%, [NaOH] / [VAc] (molar ratio) = 0.1
After saponification at 5 and a temperature of 40 ° C., the obtained polyvinyl alcohol was drained, and the same amount of NaOH as that used for saponification was added.
Re-saponified for 4 hours. Thereafter, the resultant was washed with methanol, drained and dried at 40 ° C. to obtain polyvinyl alcohol. This polyvinyl alcohol has a degree of saponification of 99.8 mol%. The polyvinyl acetate obtained by re-acetylating the polyvinyl alcohol under the same conditions as described above and repeating reprecipitation and purification in the same manner as described above was treated in acetone at 30 ° C. The viscosity average degree of polymerization determined from the measured intrinsic viscosity was 22,800.

In the above-mentioned seed polymerization, the charged amount A (mol / liter) of the water-soluble initiator (here, potassium persulfate) per unit volume (1 liter) of the charged reaction solution.
Is 3.02 × 10 ⁻⁵ , and the charged amount B (mol / unit) of the water-soluble initiator (here, potassium persulfate) per vinyl ester-based polymer particle in the seed emulsion is 4.0.
It was 13 × 10 ^-22 . In addition, the unit volume of the charged reaction solution (1
The charged amount C (mol / liter · second) of the water-soluble initiator (here, potassium persulfate) per unit time (second) per liter) is 1.68 × 10 ^-9 and is defined as above. The measured Y value was 1.38 × 10 ^-2 .

Comparative Example 6 In the same reactor as in Example 12, 1000 ion-exchanged water
Parts, vinyl acetate 1000 parts, polyoxyethylene [PO
E (40)] nonylphenyl ether (nonipol 40
0, Sanyo Chemical Co., Ltd.) 40 parts, Rongalit 1.25
Parts, was charged with FeSO ₄ · 7H ₂ O0.12 parts, after boiling for 30 minutes, while introducing nitrogen, and cooled to 5 ° C., 0.075% of over-prepared with deionized water which is separately degassed Polymerization was started while hydrogen oxide aqueous solution was continuously added uniformly at 10 parts / hr. During the polymerization, the system was sealed with nitrogen gas in the same manner as in Example 12 to suppress the entry of oxygen. After 3.5 hours, when the polymerization rate reached 60.2% (maximum polymerization rate: 17.2% / hr), the addition of the hydrogen peroxide solution was stopped, and the polymerization was stopped. When the average particle size of the obtained emulsion was measured, it was 0.28 μm, and the number of polyvinyl acetate particles per unit volume of the emulsion was 4.2 × 10 ¹³ particles / ml.

The emulsion thus obtained was added to a solution of 1 part of hydroquinone monomethyl ether in 25,000 parts of methanol at room temperature and dissolved with stirring.
After dissolution, unreacted vinyl acetate was removed in the same manner as in Example 12 to obtain a methanol solution of polyvinyl acetate. A part of this solution was subjected to a saponification reaction and a re-acetylation reaction under the same conditions as in Example 12 to obtain purified polyvinyl acetate. About 30% of the polyvinyl acetate in acetone
The viscosity average degree of polymerization determined from the intrinsic viscosity measured in Step 1 is 1.
It was 4,000.

Then, a methanol solution of polyvinyl acetate was saponified, re-saponified, washed, and treated under the same conditions as in Example 12.
Drying was performed to obtain polyvinyl alcohol. This polyvinyl alcohol has a degree of saponification of 99.8 mol%. The polyvinyl acetate obtained by re-acetylating the polyvinyl alcohol under the same conditions as described above and repeating reprecipitation and purification in the same manner as described above was treated with acetone in acetone at 30%. The viscosity average degree of polymerization determined from the intrinsic viscosity measured at ° C. was 14,000.

Although the emulsion polymerization was carried out under almost the same polymerization conditions, the viscosity average degree of polymerization was 14,000 in the 5 ° C. emulsion polymerization shown in Comparative Example 6, whereas
In the seed polymerization at 5 ° C. of the present invention shown in Example 12, the viscosity average degree of polymerization was 22,800, which indicates that polyvinyl acetate and polyvinyl alcohol having a very high degree of polymerization can be easily obtained. In addition, in the emulsion polymerization at 5 ° C. shown in Comparative Example 6, since the emulsifier was used as the stabilizer, the obtained polyvinyl alcohol was thought to contain the emulsifier. In the case of seed polymerization at ℃, polyvinyl alcohol is used as a stabilizer,
The polyvinyl alcohol obtained is pure without emulsifiers.

Example 13 In the same reactor as in Example 12, 1000 ion-exchanged water
Parts, vinyl acetate 100 parts, polyoxyethylene [POE
(35)] 12.5 parts of an 80% aqueous solution of sodium nonylphenyl ether sulfate (Eleminol ES-70, manufactured by Sanyo Chemical Co., Ltd.), 0.40 parts of Rongalite and FeSO ₄
0.03 parts of 7H ₂ O was charged and boiled, then cooled to 40 ° C., and prepared using degassed deionized water separately.
The polymerization was started while a 032% aqueous solution of potassium persulfate was continuously added uniformly at 8 parts / hr. When the polymerization rate reached 42.8% after 0.2 hours, the addition of the aqueous potassium persulfate solution was stopped, and the mixture was further stirred at 40 ° C. for 0.8 hours.
The polymerization rate was 58.2%. The average particle size of the obtained emulsion was 0.097 μm. The number of polyvinyl acetate particles per unit volume of the emulsion was 1.2 × 10 ¹⁴ particles / ml.

Separately, after boiling for 30 minutes, 900 parts of vinyl acetate cooled to 40 ° C. while introducing nitrogen was added to the seed emulsion obtained above and adjusted to 40 ° C. 0.0 prepared using degassed deionized water separately.
Polyvinyl alcohol having a concentration of 10% prepared by using a 32% potassium persulfate solution at 8 parts / hr and separately degassed ion-exchanged water (polymerization degree 2000, saponification degree 80 mol% (PVA-420, 50) Kuraray aqueous solution
The polymerization was started while uniformly and continuously adding at parts / hr. During polymerization, the system was sealed with nitrogen gas to keep oxygen from entering. After 3.5 hours, the polymerization rate is 79.3% (maximum polymerization rate is 28%
/ Hr), the addition of the aqueous potassium persulfate solution and the aqueous vinyl alcohol solution was stopped to stop the polymerization. When the average particle size of the obtained emulsion was measured, it was 0.89 μm. The number of polyvinyl acetate particles per unit volume of the emulsion was 1.4 × 10 ¹² particles / ml.

At room temperature, 0.6 part of hydroquinone monomethyl ether was dissolved in 15,000 parts of dimethyl sulfoxide at room temperature, and the emulsion was poured into the emulsion and dissolved with stirring. After dissolution, unreacted vinyl acetate was removed at 70 ° C. while adding dimethyl sulfoxide under reduced pressure to obtain a solution of polyvinyl acetate in dimethyl sulfoxide. A part of this solution is taken, put into distilled water, and once polyvinyl acetate is taken out, reprecipitation and purification are repeated several times with acetone-n-hexane. Vinyl acetate was obtained. The polyvinyl acetate was dissolved in methanol, and the concentration was 10%, [NaOH] / [VA
c] (molar ratio) = 0.10 and saponification at a temperature of 40 ° C.
Polyvinyl alcohol was obtained. The polyvinyl alcohol was re-acetylated and purified under the same conditions as in Example 12 to obtain polyvinyl acetate. The viscosity average polymerization degree of the polyvinyl acetate was 5,200.

Next, a solution of polyvinyl acetate in dimethyl sulfoxide was saponified at a concentration of 10%, [NaOH] / [VAc] (molar ratio) = 0.15, at a temperature of 40 ° C. and in a nitrogen stream. After draining, Example 1
Re-saponification, washing with methanol and drying were performed in the same manner as in Example 2 to obtain polyvinyl alcohol. The polyvinyl alcohol had a degree of saponification of 99.8 mol%, and the viscosity-average degree of polymerization of the polyvinyl acetate obtained by repeating re-acetylation and re-precipitation purification in the same manner as described above was 5,200.

In the above-mentioned seed polymerization, the charged amount A (mol / liter) of a water-soluble initiator (here, potassium persulfate) per unit volume (1 liter) of the charged reaction solution.
Is 1.46 × 10 ⁻⁶ , and the charged amount B (mol / unit) of the water-soluble initiator (here, potassium persulfate) per vinyl ester-based polymer particle in the seed emulsion is 1.
It was 22 × 10 ^-23 . In addition, the unit volume of the charged reaction solution (1
The charge C (mol / liter · second) of the water-soluble initiator (here, potassium persulfate) per unit time (second) per liter) is 1.16 × 10 ^−10, which is defined as above. The Y value was 5.80 × 10 ⁻⁴ .

Comparative Example 7 1000 ion-exchanged water was placed in the same reactor as in Example 12.
Parts, vinyl acetate 1000 parts, polyoxyethylene [PO
E (35)] of sodium nonylphenyl ether sulfate (Eleminol ES-70, manufactured by Sanyo Chemical Industries, Ltd.)
% Aqueous solution 50 parts, Rongalit 0.80 parts, FeSO _4.
After charging 0.06 parts of 7H ₂ O and boiling for 30 minutes, the mixture was cooled to 40 ° C. while introducing nitrogen, and a 0.025% aqueous potassium persulfate solution adjusted using degassed ion-exchanged water was added. The polymerization was started while uniformly and continuously adding at parts / hour. After 3.0 hours, the polymerization rate is 77.8% (the maximum polymerization rate is 2).
(9% / hr), the addition of the aqueous potassium persulfate solution was stopped, and the polymerization was stopped.

The average particle size of the obtained emulsion was measured to be 0.30 μm, and the number of polyvinyl acetate particles per unit volume of the emulsion was 4.4 × 10 ¹⁴ . The emulsion thus obtained was obtained in the same manner as in Example 13 to obtain a solution of polyvinyl acetate in dimethyl sulfoxide. Further, a part of this solution was taken out of the purified polyvinyl acetate in the same manner as in Example 13, and the concentration was adjusted to 1%.
A 0% methanol solution was prepared. Then, Example 12
Saponification, purification, drying, re-acetylation and drying were carried out in the same manner as in the above to obtain purified polyvinyl acetate. The viscosity-average degree of polymerization of the polyvinyl acetate determined from the intrinsic viscosity measured at 30 ° C. in acetone was 3,500.

Next, the dimethyl sulfoxide solution of polyvinyl acetate was saponified, re-saponified, washed with methanol and dried under the same conditions as in Example 13 to obtain polyvinyl alcohol. The polyvinyl alcohol has a degree of saponification of 99.
The viscosity-average degree of polymerization was measured to be 3,500 for polyvinyl acetate obtained by repeating re-acetylation and re-precipitation purification in the same manner as described above.

Comparative Example 8 Polymerization, saponification and purification were carried out in the same manner as in Example 12 except that the polymerization conditions shown below were changed, and the saponification degree and viscosity average of the obtained polyvinyl acetate and polyvinyl alcohol were obtained. The degree of polymerization was measured. Only the points where the polymerization conditions were changed are shown below. Polyoxyethylene [POE (30)] sodium lauryl ether sulfate (TRAX K-300, NOF CORPORATION) as an emulsifier to be charged into the reactor
), 40 parts of a 35% aqueous solution of Rongalit,
FeSO ₄ · 7H ₂ O 0.15 parts were charged deionized water and vinyl acetate methanol 360 parts and Example 12 with the same amount, after boiling deaeration, cooled to -20 ° C., 0.020 of hydrogen peroxide The polymerization was started while water was continuously added uniformly at 10 parts / hr. After 6.0 hours, when the polymerization rate reached 51.2% (maximum polymerization rate 9.1% / hr), the polymerization was stopped. When the average particle size of the obtained emulsion was measured
0.317 μm, and the number of polyvinyl acetate particles per emulsion unit volume was 1.7 × 10 ¹³ particles / ml.

The emulsion thus obtained was added to a solution of 1 part of hydroquinone monomethyl ether in 70,000 parts of methanol at room temperature and dissolved with stirring.
The viscosity average degree of polymerization of the polyvinyl acetate was 24,000. The polyvinyl alcohol obtained by saponifying the polyvinyl acetate had a saponification degree of 99.8 mol% and a viscosity average polymerization degree of 24,000.

Example 1 shown below with the same polymerization temperature
Comparative Example 8, which does not rely on sheet polymerization, has a lower degree of polymerization of the obtained polyvinyl acetate and polyvinyl alcohol than Comparative Example 5.

Examples 14 to 16 and Comparative Examples 9 and 10
Polymerization, saponification, purification, etc. were performed in the same manner as in Example 12 except that the production conditions for seed polymerization shown in the table were changed. Table 3 shows the production results of the seed emulsion.
Table 4 shows the results of the seed polymerization.

[0109]

[Table 11]

[0110]

[Table 12]

[0111]

[Table 13]

[0112]

[Table 14]

[0113]

[Table 15]

[0114]

[Table 16]

[0115]

The method for producing a vinyl ester polymer by the seed polymerization of the present invention and the method for producing a vinyl alcohol polymer using the vinyl ester polymer obtained by the seed polymerization are as compared with the conventional method. This is a novel production method capable of easily obtaining a pure vinyl ester polymer and a vinyl alcohol polymer having a high degree of polymerization and possibly containing no emulsifier on an industrial scale. The reason for this is not clear, but when emulsion polymerization of vinyl ester is carried out, the presence of seed particles in advance makes it possible to grow the seed particles without forming new particles, thereby producing a highly polymerized polymer. It seems to be obtained. The vinyl alcohol-based polymer obtained by the present invention can be used in new fields such as paper processing agents, fiber processing agents, stabilizers for emulsions, high-strength fibers and high-durability films, taking advantage of the above characteristics. It has extremely high industrial value such as used.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-59-53514 (JP, A) JP-A-57-115410 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08F 2/16-2/30

Claims (8)

(57) [Claims] 1. A unit reaction solution (1 volume) prepared by using a vinyl ester polymer emulsion as a seed emulsion.
1 × 10 ^-8 ~
Seed polymerization of vinyl ester under the conditions of 2 × 10 ⁻⁴ mol and the charged amount of water-soluble initiator per vinyl ester polymer particle in the seed emulsion is 1 × 10 ⁻²⁸ to 1 × 10 ⁻²⁰ mol A process for producing a vinyl ester polymer. 2. The process for producing a vinyl ester polymer according to claim 1, wherein the polymerization temperature is -60 to 40 ° C. 3. The average particle size of the vinyl ester polymer particles in the seed emulsion before the start of seed polymerization is 0.005.
The method for producing a vinyl ester polymer according to claim 1, wherein the number of particles of the vinyl ester polymer is from 10 ¹² to 10 ¹⁶ per unit volume (1 milliliter) of the seed emulsion. 4. The amount of the vinyl ester polymer (A) relative to the total amount ((A) + (B)) of the vinyl ester polymer (A) and vinyl ester (B) in the seed emulsion before the start of seed polymerization. Ratio [(A) / ((A) +
2. The method for producing a vinyl ester polymer according to claim 1, wherein the seed polymerization is started when (B)) × 100] is 0.01 to 20%. 5. The method for producing a vinyl ester polymer according to claim 1, wherein the seed polymerization is continuous polymerization. 6. The method for producing a vinyl ester polymer according to claim 1, wherein the degree of polymerization of the vinyl ester polymer obtained by seed polymerization is 4000 or more. 7. A method for producing a vinyl alcohol-based polymer, comprising saponifying the vinyl ester-based polymer obtained by the method according to claim 1 or 5. 8. The process for producing a vinyl alcohol polymer according to claim 7, wherein the average degree of polymerization of the obtained vinyl alcohol polymer is 4000 or more.