JP6866130B2 - Dispersion aid for suspension polymerization, method for producing vinyl polymer using it, and vinyl chloride resin - Google Patents

Description

The present invention is a polyvinyl alcohol-based polymer that can be suitably used as a dispersion aid for suspension polymerization of vinyl-based compounds, and chloride produced by suspend-polymerizing this polyvinyl alcohol-based polymer as a dispersion aid. The present invention relates to a vinyl resin and a method for producing the same.

A vinyl chloride-based resin (or hereinafter, sometimes referred to as a vinyl chloride-based polymer) is generally a suspended weight in which a vinyl chloride monomer is dispersed in an aqueous medium together with a polymerization initiator, a dispersion stabilizer, or the like to carry out polymerization. Manufactured legally.
The dispersant used at that time is a so-called "dispersion stabilizer" added to stabilize the dispersibility of the vinyl chloride monomer and adjust the particle size of the produced vinyl chloride resin. There is a so-called "dispersion aid" added to increase the porosity of vinyl chloride resin particles.

Conventionally, polyvinyl alcohol (PVA), hydroxypropylmethyl cellulose and the like have been used as "dispersion stabilizers" (or hereinafter, may be referred to as primary dispersants) (see Patent Documents 1 to 3). Further, as the "dispersion aid", PVA having a lower saponification degree than the above-mentioned primary dispersant is used (see Patent Document 4).
For example, in the method for producing a vinyl chloride polymer described in Patent Document 4, PVA having a saponification degree of 75 to 85 mol% is used as a dispersion stabilizer, and a saponification degree of 20 to 57 mol is used as a dispersion aid. % PVA is used.
In addition, as described in Patent Documents 5 to 7, various proposals have been made for improving the performance of the dispersion aid, for example, improving the porosity of the vinyl chloride resin particles.

However, regardless of the polymerization conditions, even when a large amount is used to obtain a high porosity, a stable and good polymer can be obtained with less scale adhesion to the polymerization tank, and there are no coarse particles. So far, no dispersion aid for suspension polymerization has been obtained, which has a high porosity and can obtain a vinyl chloride-based resin having excellent plasticizer absorbability. In particular, in order to obtain a vinyl chloride resin having a very high porosity, it is necessary to increase the amount of the dispersion aid added, but in this case, there is a problem that the polymerization becomes unstable.

On the other hand, PVA having a saponification degree lower than 60 mol%, which is used as a dispersion aid, has a drawback that it cannot be used as an aqueous solution or an aqueous solution because it has a low affinity for water. In order to make up for this drawback, Ken introduced ionic groups such as carboxylic acid group, sulfonic acid group and amino group and hydrophilic group other than polyvinyl alcohol such as polyoxyalkylene into the molecule as in Patent Documents 8 to 17. A method for producing a vinyl chloride resin using PVA having a low degree of conversion as a dispersion aid has been proposed.

However, in the dispersion aids into which an ionic group has been introduced as described in Patent Documents 8 to 17, although the water solubility and water dispersibility are improved, the amount of the buffer used during suspension polymerization and the buffer The range (3 to 8) of the pH value in the polymerization system changes depending on the timing of addition, the oxygen concentration in the polymerization system, etc., and its characteristics (porosity up, uniformity of porosity distribution, demonomerization and absorption of plasticizer). In some cases, it may not be possible to fully exert (improvement of function, etc.), and there are concerns that polymerization stability may be poor and scale adhesion may be significant. Therefore, it has been desired to develop a dispersion aid that is water-soluble or water-dispersible and has excellent polymerization stability.

Further, a dispersion aid having improved water solubility and water dispersibility by introducing an ionic group can obtain an aqueous liquid having a PVA content of 10% by mass or less, but at a PVA content of 20% by mass or more. There is a problem that the dispersion aid agglomerates and a high content aqueous liquid cannot be obtained.

JP-A-2002-003510 Japanese Unexamined Patent Publication No. 2003-327607 Japanese Unexamined Patent Publication No. 2003-238606 Japanese Unexamined Patent Publication No. 2005-281680 Japanese Unexamined Patent Publication No. 04-85303 Japanese Unexamined Patent Publication No. 2004-115821 Japanese Unexamined Patent Publication No. 04-93301 Japanese Unexamined Patent Publication No. 04-154810 Japanese Unexamined Patent Publication No. 05-345805 Japanese Unexamined Patent Publication No. 10-168128 Japanese Unexamined Patent Publication No. 10-259213 International Publication No. 91/15518 Japanese Unexamined Patent Publication No. 9-77807 Japanese Unexamined Patent Publication No. 10-152508 Japanese Unexamined Patent Publication No. 9-100301 Japanese Unexamined Patent Publication No. 9-18385 JP-A-2002-37807

According to the present invention, when used for suspension polymerization of a vinyl compound, even when used in a large amount, dispersion that hardly adheres to the polymerization tank on a scale and a stable and good polymer (vinyl resin) can be obtained. The purpose is to provide an auxiliary agent.
The present invention also provides a dispersion aid for suspension polymerization capable of obtaining a vinyl resin (particularly, a vinyl chloride resin) without coarse particles when used for suspension polymerization of a vinyl compound. The purpose is.
Another object of the present invention is to provide a dispersion aid for suspension polymerization capable of obtaining a vinyl resin (particularly, a vinyl chloride resin) having excellent porosity and plasticizer absorbability.
Another object of the present invention is to provide an aqueous liquid which has good stability and a viscosity which is easy to handle even at a high concentration and is useful as a suspension polymerization dispersion aid for vinyl compounds.
Another object of the present invention is to provide a method for producing a vinyl resin having excellent plasticizer absorbability and the like by using the dispersion aid.

In view of such circumstances, as a result of intensive studies, the present inventors have an acetal group (a) having an olefin-based unsaturated double bond, a saponification degree of 45 to 60 mol%, and an average degree of polymerization of 120. A dispersion aid for suspension polymerization containing a polyvinyl alcohol-based polymer (A) having a block character of ~ 400 and a block character of 0.5 or more is used in a suspension polymerization tank for vinyl chloride even when used in a large amount. It was found that a vinyl chloride-based resin can be stably obtained with little adhesion of the scale.
In addition, the present inventors have found that the aqueous liquid containing such a dispersion aid for suspension polymerization contains 30 to 50% by mass of the PVA-based polymer (A) even though the saponification degree is lower than 60 mol%. It was found that even when the content is%, it is stable as an aqueous liquid and has a viscosity that is easy to handle.
The present inventors have further studied and completed the present invention.

That is, the present invention relates to the following dispersion aids for suspension polymerization.
[1] Polyvinyl alcohol type having an acetal group (a) having an olefin-based unsaturated double bond, a degree of saponification of 45 to 60 mol%, an average degree of polymerization of 120 to 400, and a block character of 0.5 or more. A dispersion aid for suspension polymerization containing the polymer (A).
[2] The amount of modification of the unit containing the acetal group (a) in the polyvinyl alcohol-based polymer (A) is 0.01 to 10 mol% per monomer unit of the polyvinyl alcohol-based polymer (A). ] The dispersion aid for suspension polymerization described.
[3] The dispersion aid for suspension polymerization according to the above [1] or [2], which is present in a polymerization system together with a water-soluble polymer for suspension polymerization.
[4] The dispersion aid for suspension polymerization according to the above [3], wherein the water-soluble polymer is a polyvinyl alcohol-based polymer having a saponification degree of 65 to 90 mol%.
[5] The dispersion aid for suspension polymerization according to any one of [1] to [4] above, which is used for polymerization of vinyl-based monomers.
[6] The dispersion aid for suspension polymerization according to the above [5], wherein the vinyl-based monomer contains vinyl chloride.
[7] An aqueous solution containing the dispersion aid for suspension polymerization according to any one of [1] to [6] above.
[8] The aqueous solution according to [7] above, which contains 30 to 50% by mass of the polyvinyl alcohol-based polymer (A).
[9] The aqueous solution according to the above [7] or [8], which has a pH of 4.5 to 7.0.
[10] A method for producing a vinyl-based resin in which a vinyl-based monomer is suspended-polymerized in the presence of the dispersion aid for suspension polymerization according to any one of the above [1] to [6].
[11] The production method according to the above [10], wherein suspension polymerization is further carried out in the presence of a water-soluble polymer.
[12] The production method according to the above [11], wherein the water-soluble polymer is a polyvinyl alcohol-based polymer having a saponification degree of 65 to 90 mol%.
[13] The production method according to any one of [10] to [12] above, wherein the vinyl-based monomer contains vinyl chloride.
[14] Polyvinyl alcohol type having an acetal group (a) having an olefin-based unsaturated double bond, a degree of saponification of 45 to 60 mol%, an average degree of polymerization of 120 to 400, and a block character of 0.5 or more. A vinyl-based resin containing the polymer (A) as a polymerization component.
[15] The amount of modification of the unit containing the acetal group (a) in the polyvinyl alcohol-based polymer (A) is 0.01 to 10 mol% per monomer unit of the polyvinyl alcohol-based polymer (A). ] Described vinyl resin.
[16] The vinyl-based resin according to the above [14] or [15], which is a vinyl chloride-based resin.

According to the present invention, when it is used for suspension polymerization of a vinyl-based monomer, it can be polymerized regardless of the polymerization conditions, and it is used in a large amount to obtain a vinyl-based resin having a high porosity. It is possible to provide a dispersion aid for suspension polymerization, which can stably obtain a good polymer (vinyl resin) with less scale adhesion to the polymerization tank even in such a case.
Further, by using the dispersion aid for suspension polymerization of the present invention, a vinyl resin without coarse particles (particularly, a vinyl chloride resin) can be obtained, and vinyl having excellent porosity and plasticizer absorbability can be obtained. A system resin (particularly, a vinyl chloride resin) can also be obtained.
Such a dispersion aid of the present invention contains a PVA-based polymer, but the aqueous liquid containing the dispersion aid of the present invention has good stability even at a high concentration of the PVA-based polymer and can be handled. Has an easy viscosity. Therefore, if the aqueous solution is used, suspension polymerization of the vinyl compound can be stably performed even if the PVA-based polymer has a high concentration in the polymerization system, and scale adhesion to the polymerization tank is reduced. be able to.
Furthermore, according to the present invention, it is possible to provide a method for producing a vinyl resin having excellent porosity, plasticizer absorbency, etc., using the dispersion aid.

Hereinafter, embodiments for carrying out the present invention will be described in detail. The present invention is not limited to the embodiments described below.
The dispersion aid (additive, dispersant) for suspension polymerization of the present invention has an acetal group (a) having an olefin-based unsaturated double bond, has a saponification degree of 45 to 60 mol%, and an average degree of polymerization. It is characterized by containing a polyvinyl alcohol-based polymer (A) having a degree of 120 to 400 and a block character of 0.5 or more. The dispersion aid for suspension polymerization of the present invention may contain one kind of PVA-based polymer (A) or two or more kinds.

[PVA-based polymer (A)]
In the PVA-based polymer (A), the acetal group (a) having an olefin-based unsaturated double bond is not particularly limited, but is, for example, a group that can be introduced via the OH group of the PVA-based polymer (B). Yes, a group derived from a carbonyl compound having an olefin-based unsaturated double bond is preferable. The acetal group (a) is preferably a cyclic acetal group.
The carbonyl compound is not particularly limited, and examples thereof include aldehydes and ketones, and preferably have an olefin-based unsaturated double bond.
When a carbonyl compound having an olefin-based unsaturated double bond is used, for example, two adjacent OH groups in the PVA-based polymer (B) are acetalized with an aldehyde and / or a ketone having an olefin-based unsaturated double bond. The PVA-based polymer (A) having an acetal group (a) having an olefin-based unsaturated double bond can be obtained.

As the aldehyde, a monoaldehyde having an olefin-based unsaturated double bond is preferable.
In the monoaldehyde (or acetal group (a)) having an olefin-based unsaturated double bond, the number of olefin-based unsaturated double bonds is not particularly limited, and is, for example, 1 to 5 or the like. The aldehyde may have a substituent (for example, a hydroxyl group, a nitro group, an aromatic group, etc.).
The monoaldehyde having an olefin-based unsaturated double bond is not particularly limited, and is, for example, alkenal [for example, achlorine, crotonaldehyde, metachlorine, 3-butenal, 3-methyl-2-butenal, 2-methyl-2. -Butenal, 2-Pentenal, 3-Pentenal, 4-Pentenal, 2-Hexenal, 3-Hexenal, 4-Hexenal, 5-Hexenal, 2-Ethylcrotonaldehyde, 2-Methyl-2-Pentenal, 3- (Dimethylamino) ) Alkenals with 3 to 30 carbon atoms such as achlorein, myristolene aldehyde, palmitre aldehyde, olein aldehyde, ellaidin aldehyde, baxen aldehyde, gadrain aldehyde, elca aldehyde, nervone aldehyde, linole aldehyde, citroneral, cinnam aldehyde, etc., preferably carbon number 3 to 25 alkhenals], alkadienals [eg, 2,4-pentadienals, 2,4-hexadienals, 2,6-nonadienals, citrals and the like, alkazienals having 5 to 30 carbon atoms, preferably Arcadienal with 5 to 25 carbon atoms], Arcatrienal [for example, alkatrienal with 7 to 30 carbon atoms such as linolenealdehyde and eleostearaldehyde, preferably alkatrienal with 7 to 25 carbon atoms], Arca Tetraenal [for example, alkatetraenal having 9 to 30 carbon atoms such as stearidonaldehyde and arachidonealdehyde, preferably alkatetraenal having 9 to 25 carbon atoms], alkapentaenal [for example, eikosapentaenealdehyde and the like]. Aldehydes having 11 to 30 carbon atoms, preferably 11 to 25 carbon atoms] and other unsaturated monoaldehydes can be mentioned, but those in which these cis-trans isomers are present can be used. Includes both cis and trans forms. These monoaldehydes having an olefin-based unsaturated double bond can be used alone or in combination of two or more.

A multivalent aldehyde such as dialdehyde is not preferable because the PVA-based polymer (A) obtained by acetalization may be insolubilized.

In the present invention, acetal, which is a condensate of the monoaldehyde and an alcohol, can also be used in place of the monoaldehyde having an olefin-based unsaturated double bond described above. The acetal is not particularly limited, and examples thereof include a condensate with a primary alcohol.

As the ketone, a monoketone having an olefin-based unsaturated double bond is preferable.
In the monoketone having an olefin-based unsaturated double bond, the number of olefin-based unsaturated double bonds is not particularly limited, and is, for example, 1 to 5 or the like. The ketone may have a substituent (for example, a hydroxyl group, a nitro group, an aromatic group, etc.).
The monoketone having an olefin-based unsaturated double bond is not particularly limited, and is, for example, an unsaturated aliphatic monoketone {for example, an alkenone [for example, an alkenone having 4 to 30 carbon atoms such as methyl vinyl ketone, preferably an alkenone having 4 carbon atoms. ~ 25 alkenones] etc.} and the like. These ketones can be used alone or in combination of two or more.

Further, the PVA-based polymer (A) may have an acetal group (b) that does not belong to the category of the acetal group (a). The method for introducing the acetal group (b) is not particularly limited, and for example, a method of acetalizing two adjacent OH groups in the PVA-based polymer (B) with a monoaldehyde having no olefin-based unsaturated double bond. Can be mentioned.
Examples of monoaldehydes having no olefin-based unsaturated double bond include aliphatic aldehydes such as formaldehyde, acetaldehyde, propionaldehyde, butylaldehyde, barrel aldehyde, and hexanal, and aromatic aldehydes such as benzaldehyde, tolualdehyde, and terephthalaldehyde acid. And so on.

The PVA-based polymer (A) has, for example, a unit represented by the following formula (1) as a unit having an acetal group (a) having an olefin-based unsaturated double bond.

（式中、Ｒ^１はオレフィン系不飽和二重結合を有する基を示し、Ｒ^２は水素原子又は置換基を示す。）

(In the formula, R ¹ represents a group having an olefin-based unsaturated double bond, and R ² represents a hydrogen atom or a substituent.)

In R ^1, examples of the group having an olefinically unsaturated double bond, for example, an alkenyl group [for example, an alkenyl group having 2 to 30 carbon atoms, preferably an alkenyl group having 2 to 16 carbon atoms, an alkadienyl group [for example, An alkazienyl group having 4 to 30 carbon atoms such as a 2,4-alkazienyl group and a 2,6-alkazienyl group, preferably an alkazienyl group having 4 to 16 carbon atoms], an alkathylenel group [for example, an alkaryl group having 6 to 30 carbon atoms]. Enyl group, preferably an alkatrienyl group having 6 to 16 carbon atoms], alkatetraenyl group [for example, an alkatetraenyl group having 8 to 30 carbon atoms, preferably an alkatetraenyl group having 8 to 16 carbon atoms], alkapenta. Examples thereof include an enyl group [for example, an alkampenyl group having 10 to 30 carbon atoms, preferably an alkampentaenyl group having 10 to 16 carbon atoms] and the like. These groups are further substituted with one or more substituents (eg, halogen atom, hydroxyl group, carboxyl group, ether group, ester group, alkoxy group, nitro group, amino group, aromatic group, etc.). You may.

In R ^2, as the substituent, for example, an organic residue such as a hydrocarbon group.
Examples of the hydrocarbon group include an aliphatic group {for example, a saturated aliphatic group (for example, an alkyl group having 1 to 20 carbon atoms) and an unsaturated aliphatic group (for example, an alkenyl group having 2 to 20 carbon atoms). }, An aromatic group (for example, an aromatic hydrocarbon group having 6 to 20 carbon atoms, etc.) and the like. The hydrocarbon group may be further substituted with one or more substituents (eg, halogen atom, hydroxyl group, carboxyl group, ether group, ester group, alkoxy group, nitro group, amino group, etc.).

Regarding the saponification degree of the PVA-based polymer (A), the saponification degree determined by the method for measuring the saponification degree of PVA specified in JIS K 6726 is usually 45 mol% to 60 mol%.
When the degree of saponification is 60 mol% or less, the effect as a dispersion aid is excellent, the porosity of the obtained vinyl resin and the absorbability of the plasticizer are improved, and the stability of suspension polymerization is excellent. It is preferable from the viewpoint that the particle size of the vinyl resin does not easily become coarse. When the saponification degree is 45 mol% or more, it is preferable from the viewpoints of excellent dispersibility in water, excellent stability of the aqueous liquid when it is an aqueous liquid containing a dispersion aid, and the like.
The degree of saponification of the PVA-based polymer (A) can be adjusted by the degree of saponification of the PVA-based polymer (B) which is the raw material. For example, when the PVA-based polymer (B) is acetalized with a monoaldehyde having an olefin-based unsaturated double bond and / or a monoketone, if water is contained in the reaction system, the PVA-based polymer undergoing the acetalization reaction The change in the degree of saponification can be reduced, and the difference in the degree of saponification between the PVA-based polymer (A) and the PVA-based polymer (B) can be adjusted to, for example, about 0 to 5 mol%.

The (average) degree of polymerization of the PVA-based polymer (A) is not particularly limited, but the degree of polymerization determined by the method for measuring the average degree of polymerization of PVA specified in JIS K 6726 is usually 120 to 400, more preferably. Is 160-400.
When the degree of polymerization of the PVA-based polymer (A) is 120 or more, the performance as a dispersion aid of the present invention is excellent, and the particle size of the obtained vinyl-based resin is less likely to be coarsened, which is preferable. Further, when the degree of polymerization is 400 or less, the aqueous liquid has excellent dispersibility in water, the viscosity of the aqueous liquid becomes good when it is made into an aqueous liquid containing a dispersion aid, and the fluidity and handleability are excellent. It is preferable from the viewpoint of excellent dispersion in an aqueous medium when added to a suspension polymerization system.
The degree of polymerization of the PVA-based polymer (A) can be adjusted by the degree of polymerization of the PVA-based polymer (B) as a raw material, and usually reflects the degree of polymerization of the PVA-based polymer (B). be able to.

The block character of the residual fatty acid group of the PVA-based polymer (A) is usually 0.5 or more, preferably 0.6 to 0.9. When the block character is 0.5 or more, the dispersibility in water is excellent, and when the aqueous liquid containing a dispersion aid is used, the viscosity of the aqueous liquid is good, and the fluidity and handleability are excellent. preferable. When the block character is 0.9 or less, the porosity of the obtained vinyl resin is improved, and the amount of plasticizer absorbed is excellent, which is preferable.

Here, the block character (η) of the residual fatty acid group is an index showing the distribution of the residual fatty acid group of the PVA-based polymer, and is obtained by analyzing three peaks appearing in the methylene region in ^{the 13 C-NMR spectrum.} Be done. The above three peaks correspond to three 2-unit chain structures corresponding to (OH, OH), (OH, OR), (OR, OR), and the absorption intensity thereof is proportional to the three structures. ing. The block character (η) is represented by the following (Equation 2). The residual fatty acid group (OR group) is a fatty acid group contained in a fatty acid vinyl ester unit (that is, a unit derived from a fatty acid vinyl ester). For example, when vinyl acetate is used as the fatty acid vinyl ester, an acetoxy group. (OAc group) is shown.

(Equation 2) η = (OH, OR) / [2 (OH) (OR)]
[In the formula, (OH, OR) represents the ratio of the 2-unit chain structure (OH, OR) in which the OH group and the OR group are adjacent to each other, and is determined from the intensity ratio of methylene carbon in the ^{13 C-NMR spectrum.} Further, in the formula, (OH) represents the degree of saponification, (OR) represents the ratio of residual fatty acid groups, and each is represented by a mole fraction. ]

In (Equation 2), (OH, OR) represents the ratio of (OH, OR) to the total amount of (OH, OH), (OH, OR) and (OR, OR).
Further, (OH) and (OR) represent the ratio of (OH) and (OR) to the total amount of (OH) and (OR) contained in the PVA-based polymer (A).

This block character usually takes a value of 0 to 2, and the closer it is to 0, the higher the blocking property of the residual fatty acid group distribution, the closer it is to 1, the higher the randomness, and the closer it is to 2, the higher the alternation. Indicates high. The blocking property of the residual fatty acid group affects the dispersibility of vinyl-based monomers such as vinyl chloride monomer. Regarding this block character, the measurement method and the like are described in detail in "Poval", pp. 246 to 249 of the Polymer Publishing Association (published in 1981), and Macromolecules, 10,532 (1977).

The block character of the residual fatty acid group of the PVA-based polymer (A) can be adjusted by the block character of the raw material PVA-based polymer (B). For example, when the PVA-based polymer (B) is acetalized with monoaldehyde or monoketone, if water is contained in the reaction system, the change in the block character of the PVA-based polymer during the acetalization reaction can be reduced. The difference in the block character of the residual fatty acid group between the PVA-based polymer (A) and the PVA-based polymer (B) can be adjusted to, for example, about 0 to 0.1.

In the PVA-based polymer (A), the modification amount (content) of the unit having an acetal group (a) having an olefin-based unsaturated double bond is 0.01 to 0.01 per monomer unit of the PVA-based polymer (A). 10 mol% is preferable, 0.05 to 8 mol% is more preferable, and 0.1 to 8 mol% is particularly preferable.
The content of 1 mol% means that each 100 monomer units (for example, vinyl alcohol unit) has one unit having an acetal group (a) (for example, a structural unit represented by the general formula (1)). Say the case.
When the amount of modification is 0.01 mol% or more, the effect of introducing an unsaturated double bond (for example, when a dispersion aid is used for suspension polymerization of a vinyl-based monomer, high porosity is obtained in order to obtain high porosity. Even if it is used in a large amount, there is little scale adhesion and coarse graining does not occur). When the amount of modification is 10 mol% or less, the original characteristics of the PVA-based polymer (for example, dispersibility in an aqueous medium) can be maintained, which is preferable.
In the present invention, a method for measuring the amount of modification of a unit having an acetal group (a) having an olefin-based unsaturated double bond (for example, the amount of modification with a monoaldehyde and / or monoketone having an olefin-based unsaturated double bond). Is not particularly limited, but for example, a method of dissolving a PVA-based polymer (A) in a d6-DMSO solvent, ^{measuring this by 1} H-NMR, and analyzing a signal derived from a double bond, or a high-speed liquid. Examples thereof include a method of measuring and obtaining an unreacted monoaldehyde by chromatography or gas chromatography.

[PVA-based polymer (B)]
The PVA-based polymer (B) used as a raw material for the PVA-based polymer (A) is not particularly limited, but for example, a conventionally known PVA-based polymer obtained by saponifying a vinyl ester-based polymer can be used. Can be used.
The vinyl ester-based polymer can be obtained by polymerizing a vinyl ester-based monomer. The polymerization method is not particularly limited, and conventionally known methods may be followed. Examples thereof include massive polymerization, solution polymerization, suspension polymerization, emulsion polymerization and the like, and the saponification reaction carried out after controlling the degree of polymerization or after polymerization. In consideration of the above, solution polymerization using methanol as a solvent or suspension polymerization using water or water / methanol as a dispersion medium is preferable, but is not limited thereto.

The vinyl ester-based monomer that can be used for the polymerization is not particularly limited, and examples thereof include fatty acid vinyl esters such as vinyl acetate, vinyl formate, vinyl propionate, vinyl caprylate, and vinyl versatic acid. These vinyl ester-based monomers can be used alone or in combination of two or more. Of these, vinyl acetate is preferable from an industrial point of view.

When polymerizing the vinyl ester-based monomer, the vinyl ester-based monomer may be copolymerized with another monomer as long as the effect of the present invention is exhibited.
Other monomers that can be used are not particularly limited, but are, for example, α-olefin (for example, ethylene, propylene, n-butyl, isobutylene, etc.), (meth) acrylic acid and salts thereof, (meth) acrylic acid. Esters [For example, (meth) acrylate alkyl ester (eg, (meth) methyl acrylate, (meth) ethyl acrylate, (meth) acrylate n-propyl, (meth) acrylate i-propyl, (meth) (Meta) such as n-butyl acrylate, i-butyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, dodecyl (meth) acrylate, octadecyl (meth) acrylate, etc. ) C _1-20 alkyl acrylate, etc.)], (meth) acrylamide, (meth) acrylamide derivative [eg, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide , Diacetone (meth) acrylamide, (meth) acrylamide propanesulfonic acid and its salts, (meth) acrylamide propyldimethylamine and its salts or quaternary salts thereof, N-methylol (meth) acrylamide, etc.], Vinyl ethers (eg, 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, C _1-20 alkyl vinyl ether such as stearyl vinyl ether, etc.), nitriles (for example, , Acrylonitrile, methacrylonitrile, etc.), vinyl halides (eg, vinyl chloride, vinyl fluoride, etc.), vinylidene halides (eg, vinylidene chloride, vinylidene fluoride, etc.), allyl compounds (eg, allyl acetate, chloride, etc.) Allyl, etc.), unsaturated dicarboxylic acids (eg, maleic acid, itaconic acid, fumaric acid, etc.) and salts thereof or esters thereof, vinylsilyl compounds (eg, vinyltrimethoxysilane, etc.), fatty acid alkyl esters (eg, isopropenyl acetate, etc.) ) Etc. can be mentioned. These other monomers can be used alone or in combination of two or more.

When the other monomer is used, the content of the other monomer is, for example, 0.1 to 20% by mass with respect to the total amount of the vinyl ester-based monomer.

Further, in the polymerization of the vinyl ester-based monomer, a chain transfer agent may coexist for the purpose of adjusting the degree of polymerization of the obtained vinyl ester-based polymer.
The chain transfer agent is not particularly limited, and for example, aldehydes such as acetaldehyde, propionaldehyde, butylaldehyde, and benzaldehyde; ketones such as acetone, methyl ethyl ketone, hexanone, and cyclohexanone; and mercaptans such as 2-hydroxyethanethiol and dodecyl mercaptan. Kind: Organic halogens such as carbon tetrachloride, trichloroethylene and perchloroethylene are mentioned, and among them, aldehydes and ketones are preferably used. The amount of the chain transfer agent added is determined according to the chain transfer constant of the chain transfer agent to be added and the degree of polymerization of the target vinyl ester polymer, but is generally 0.1 with respect to the vinyl ester monomer. 10% by weight is desirable.

The PVA-based polymer (B) can be produced by saponifying the vinyl ester-based polymer obtained as described above.
The saponification reaction method of the vinyl ester-based polymer is not particularly limited, and a conventionally known method may be followed. For example, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide; alkaline earth metal hydroxides such as calcium hydroxide; monoethanolamine, aminoethylethanolamine, monoisopropanolamine, N- (2-). Hydroxypropyl) -ethylenediamine, 2-amino-1-butanol, 2-amino-2-methyl-1-propanol, 3-amino-1-propanol, 2-amino-2-methyl-1,3-propanediol, 2 Primary alkanolamines such as -amino-2-ethyl-1,3-propanediol, tris (hydroxyethyl) -aminomethane; diethanolamine, methylethanolamine, butylmethanolamine, N-acetylethanolamine, diisopropanolamine and the like. Secondary alkanolamines; tertiary alkanolamines such as triethanolamine, methyldiethanolamine, dimethylethanolamine, diethylethanolamine, ethyldiethanolamine, triisopropanolamine; methylamine, ethylamine, isobutylamine, t-butylamine, cyclohexylamine Primary alkylamines such as; secondary alkylamines such as dimethylamine, diethylamine, diisopropylamine; basic catalysts such as organic amines such as tertiary alkylamines such as trimethylamine, or hydrochloric acid, sulfuric acid, nitrate, phosphorus. Inorganic acids such as acids; alcohol decomposition or hydrolysis reactions using acidic catalysts such as organic acids such as formic acid, acetic acid, oxalic acid, and p-toluenesulfonic acid can be applied.
Examples of the solvent used in the saponification reaction include alcohols such as methanol and ethanol; esters such as methyl acetate and ethyl acetate; ketones such as acetone and methyl ethyl ketone; aromatic hydrocarbons such as benzene and toluene. These can be used alone or in combination of two or more.

The degree of saponification of the PVA-based polymer (B) is not particularly limited, but the degree of saponification of the PVA-based polymer (A) during the subsequent acetalization reaction is that of the raw material PVA-based polymer (B). Since the saponification degree is higher than the saponification degree, it is preferable to adjust the saponification degree to be lower than the target saponification degree of the PVA-based polymer (A) (for example, 0 to 5 mol% lower saponification degree).

The degree of polymerization of the PVA-based polymer (B) is not particularly limited, but the degree of polymerization of the PVA-based polymer (A) is the same as that of the raw material PVA-based polymer (B) in the subsequent acetalization reaction. Since it can be reflected, it is preferable to adjust the degree of polymerization to the target degree of polymerization of the PVA-based polymer (A).

The block character of the residual fatty acid group of the PVA-based polymer (B) is not particularly limited, but it is preferable to adjust the block character to the vicinity of the target block character of the PVA-based polymer (A).

The block character of the residual fatty acid group of the PVA-based polymer (B) can be adjusted by the type of saponification catalyst and solvent used when the vinyl ester-based polymer is saponified to produce the PVA-based polymer (B). ..
In order to obtain a block character of 0.6 or more, mineral acids such as hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid; and organic acids such as formic acid, acetic acid, oxalic acid, and p-toluenesulfonic acid are used for saponification. The method is simple.
There is also a method of adjusting by heating the obtained PVA-based polymer to increase the block character.

[Acetalization]
In the present invention, the method for introducing an acetal group (a) having an olefin-based unsaturated double bond into the PVA-based polymer (A) is not particularly limited. For example, a PVA-based polymer having a unit represented by the above formula (1) by acetalizing the PVA-based polymer (B) with a monoaldehyde and / or a monoketone having an olefin-based unsaturated double bond (1). A) can be obtained. The acetalization method is not particularly limited, and a known acetalization method can be used.

In acetalization, the amount of monoaldehyde and / or monoketone having an olefin-based unsaturated double bond is not particularly limited, but is, for example, 0.01 to 20 mass by mass with respect to 100 parts by mass of the PVA-based polymer (B). Parts, preferably 0.05 to 15 parts by mass, more preferably 0.1 to 10 parts by mass.

Further, the acetalization reaction is preferably carried out in the presence of an acidic catalyst. The acidic catalyst is not particularly limited, and examples thereof include inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid; and organic acids such as formic acid, acetic acid, oxalic acid, and p-toluenesulfonic acid.
The amount of the acidic catalyst used is not particularly limited, but is, for example, 0.01 to 10 parts by mass with respect to 100 parts by mass of the PVA-based polymer (B).

As a specific acetalization method, for example, (i) a vinyl ester-based polymer is saponified in a solvent such as methanol with a basic catalyst such as sodium hydroxide, and a solution of the PVA-based polymer (B) is obtained. After that, a monoaldehyde having an olefin-based unsaturated double bond and / or a monoketone and an acidic catalyst are added to acetalize the polymer, and then neutralized with a basic substance to obtain a solution of the PVA-based polymer (A); (Ii) A vinyl ester-based polymer is converted into a PVA-based polymer (B) by adding an acidic catalyst as a saponification catalyst in a solvent such as methanol to obtain a PVA-based polymer (B), and then monoaldehyde having an olefin-based unsaturated double bond and / Or a method of adding a monoketone, using the acidic catalyst used in the saponification reaction as it is, causing an acetalization reaction, and then neutralizing with a basic substance to obtain a solution of the PVA-based polymer (A); (iii). Similar to (ii) above, when a vinyl ester-based polymer is saponified by adding an acidic catalyst in a solvent to obtain a PVA-based polymer (B), a monoaldehyde having an olefin-based unsaturated double bond and / or Alternatively, a method in which a monoketone is added, an acetalization reaction is carried out, and then neutralized with a basic substance to obtain a solution of the PVA-based polymer (A); (iv) an olefin is added to the PVA-based polymer (B) prepared as an aqueous solution. A method in which a monoaldehyde and / or a monoketone having a system-unsaturated double bond is dissolved and reacted under an acidic catalyst, and then neutralized with a basic substance to obtain an aqueous solution of the PVA-based polymer (A); (v) slurry. Monoaldehyde and / or monoketone having an olefin-based unsaturated double bond is directly added to the PVA-based polymer (B) in the form of powder or powder, or the monoaldehyde and / or monoketone is added to an alcohol such as methanol, ethanol, or propanol. Alternatively, a method of adding a liquid dissolved or dispersed in water, adding an acidic catalyst to cause a reaction, neutralizing with a basic substance after the reaction, and further drying an excess solvent to obtain a PVA-based polymer (A); And so on.
In the methods (i) to (iii), the solvent can then be dried to obtain a solid, or the solvent can be replaced with water to form an aqueous solution.
In the method (iv), since it can be obtained as an aqueous solution, it can be used as it is for suspension polymerization of vinyl ester.
The method of reacting in the slurry state of (v) is easy to handle because the PVA-based polymer can be obtained as a solid.
In the methods (i) to (v), the method of using the PVA-based polymer (A) and the PVA-based polymer (B) as an aqueous liquid, and the methods of saponification, neutralization, dissolution, dispersion, and drying are described. The conventional method can be used without particular limitation.

The basic substance used for neutralization is not particularly limited, but for example, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide; alkali metal carbonates such as sodium carbonate and potassium carbonate, monoethanolamine, and the like. Aminoethylethanolamine, monoisopropanolamine, N- (2-hydroxypropyl) -ethylenediamine, 2-amino-1-butanol, 2-amino-2-methyl-1-propanol, 3-amino-1-propanol, 2- Primary alkanolamines such as amino-2-methyl-1,3-propanediol, 2-amino-2-ethyl-1,3-propanediol, tris (hydroxyethyl) -aminomethane; diethanolamine, methylethanolamine, Secondary alkanolamines such as butylmethanolamine, N-acetylethanolamine, diisopropanolamine; tertiary alkanolamines such as triethanolamine, methyldiethanolamine, dimethylethanolamine, diethylethanolamine, ethyldiethanolamine, triisopropanolamine; Primary alkylamines such as methylamine, ethylamine, isobutylamine, t-butylamine, cyclohexylamine; secondary alkylamines such as dimethylamine, diethylamine, diisopropylamine; organic amines such as tertiary alkylamines such as trimethylamine And so on.

The pH at the time of the acetalization reaction is preferably 3.0 or less from the viewpoint of the reaction rate.
The pH of neutralization is preferably 4.7 to 8.5 from the viewpoint of stability of the PVA-based polymer.

In the present invention, the PVA-based polymer (B) may be used alone, or two or more types of PVA-based polymers (B) having different characteristics may be mixed and used.

[Aqueous liquid]
The PVA-based polymer (A) may be used as it is as a dispersion aid, or may be used as an aqueous solution dissolved in water.
The aqueous liquid of the present invention may usually contain a PVA-based polymer (A) and water. The aqueous liquid is, for example, one in which the PVA-based polymer (A) is used as a dispersoid and dispersed or dissolved in water.

In the aqueous solution, the content of the PVA-based polymer (A) is preferably 30 to 50% by mass.
When the proportion of the polymer is 30% by mass or more, the compatibility between the PVA-based polymer (A) and water is excellent, the PVA-based polymer (A) does not separate from water, and the standing stability of the aqueous liquid is stable. Is preferable from the viewpoint of improving. When it is 50% by mass or less, the viscosity of the aqueous liquid is good, and the fluidity is excellent, which is preferable.

The aqueous liquid of the present invention has good stability even when the content of the PVA-based polymer (A) is 30 to 50% by mass without using an organic solvent, a dispersant or an emulsifier. Has good standing stability for more than a year.

The method for obtaining the aqueous solution is not particularly limited, and for example, a method of replacing a solvent such as alcohol at the time of acetalization with water by blowing steam or the like, or a method of adding the PVA-based polymer (A) into water under stirring. , A method of continuously stirring to dissolve or disperse PVA in water, a method of heating at the time of stirring, and the like can be mentioned.

The aqueous solution of the present invention may contain a water-soluble organic solvent or the like from the viewpoint of improving standing stability. Examples of the water-soluble organic solvent include alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol and isobutanol; esters such as methyl acetate and ethyl acetate; ethylene glycol, ethylene glycol monomethyl ether and ethylene glycol monoethyl. Glycol derivatives such as ether; and the like. In addition, you may use these organic solvents in mixture of 2 or more types.
From the viewpoint of consideration for the environment and improvement of workability, the content of the water-soluble organic solvent is preferably 3.0% by mass or less with respect to the aqueous liquid.

The pH of the aqueous solution of the present invention is preferably 4.5 to 7 as measured at 20 ° C. according to the measuring method specified in JISZ8802.
When the pH of the aqueous liquid is 4.5 or more, the degree of denaturation of the unit having an acetal group (a) in the PVA-based polymer (A) when the aqueous liquid containing the PVA-based polymer (A) is stored. Can be prevented from decreasing. When the pH exceeds 7, a neutralization reaction with the residual fatty acid group of the PVA-based polymer (A) occurs and the saponification degree increases, so that the pH does not exceed 7.
The pH of the aqueous solution of the present invention can be adjusted by the pH at the time of neutralization of the acetalization reaction. The pH of the aqueous liquid can also be adjusted by adding an acidic substance or a basic substance after preparing the aqueous liquid. As the acidic substance or basic substance, those used in the above-mentioned saponification reaction and acetalization reaction are preferably used.

The viscosity of the aqueous liquid of the present invention is preferably 10 to 5000 mPa · s, and the viscosity at 20 ° C. measured using a B-type rotational viscometer is preferably 10 to 5000 mPa · s from the viewpoint of excellent fluidity and handleability of the aqueous liquid. Is 10 to 3000 mPa · s.

[Manufacturing method of vinyl resin]
A suspension polymerization method of a vinyl-based monomer using the dispersion aid of the present invention will be described. A vinyl-based resin can be produced by suspend-polymerizing a vinyl-based monomer in the presence of the dispersion aid of the present invention.

Suspension polymerization is usually carried out by adding the dispersion aid of the present invention to an aqueous solvent (for example, water, heated water, etc.) and dispersing the vinyl-based monomer. Suspension polymerization is usually carried out in the presence of a polymerization initiator.
Further, suspension polymerization is usually carried out in the presence of a dispersion stabilizer in the polymerization system. The dispersion stabilizer refers to a so-called primary dispersant, which is usually added to adjust the particle size.

The vinyl-based monomer to be suspended-polymerized is not particularly limited, and is, for example, vinyl chloride, vinylidene halide, vinyl ether, vinyl ester (for example, vinyl acetate, vinyl benzoate, etc.), (meth) acrylic acid. , (Meta) acrylic acid ester (eg, (meth) crilic acid alkyl ester, etc.), styrene-based monomer (eg, styrene, etc.), unsaturated dicarboxylic acid (eg, maleic acid, etc.) or its anhydride, olefin (eg, olefin). Ethylene, propylene, etc.), etc., but it is preferable that at least vinyl chloride is contained. As these vinyl-based monomers, one kind or two or more kinds can be used.

A vinyl chloride-based resin can be obtained by suspend-polymerizing a vinyl-based monomer containing vinyl chloride. In the production of vinyl chloride-based resin, it is preferable that 50 to 100 mol% (or 50 to 100% by mass) of vinyl chloride is used with respect to the total amount of vinyl-based monomer used.

Examples of the dispersion stabilizer include water-soluble polymers (for example, cellulose derivatives such as methyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose and carboxymethyl cellulose, gelatin, polyvinyl alcohol, polyvinylpyrrolidone and the like).
Among these, PVA-based polymers are preferable. The PVA-based polymer may be a PVA-based polymer having a saponification degree of 60 mol% or more, and such a PVA-based polymer may have a saponification degree of 65 to 90 mol%. Among them, a PVA-based polymer having a saponification degree of 65 to 90 mol% and a PVA-based polymer having a degree of polymerization of 500 to 3500 are preferably used.

In the suspension polymerization of the vinyl-based monomer, the amount of the dispersion aid of the present invention used is not particularly limited, but is PVA-based contained in the dispersion aid with respect to 100 parts by mass of the vinyl-based monomer. The mass of the polymer (A) is usually 1 part by mass or less (for example, 0.001 to 1 part by mass), preferably 0.001 to 0.5 part by mass, and 0.005 to 0. 2 parts by mass is more preferable.
In general, suspension polymerization tends to be unstable when the amount of the dispersion aid used is large, but the dispersion aid of the present invention is used even when the amount used is large (for example, with respect to 100 parts by weight of the dispersion stabilizer). Suspension polymerization of the vinyl-based monomer can be stably carried out even when the dispersion aid is added in an amount of 50 parts by weight or more.

The mass ratio of the amount of the dispersion stabilizer added to the PVA-based polymer (A) contained in the dispersion aid of the present invention cannot be unequivocally determined depending on the type of the dispersion stabilizer, but 90/10 to 30/70. Is preferable, and 80/20 to 50/50 is particularly preferable.
Generally, if the ratio of the dispersion aid used (particularly, the ratio of the dispersion aid to the dispersion stabilizer) is increased, a vinyl resin having a high porosity can be obtained, but suspension polymerization becomes unstable. easy. By using the dispersion aid of the present invention, stable suspension polymerization is possible even if the dispersion aid is used at a high usage ratio (particularly, a high usage ratio with respect to the usage amount of the dispersion stabilizer).
The dispersion stabilizer and the dispersion aid may be charged all at once in the initial stage of polymerization, or may be separately charged in the middle of polymerization.

The dispersion aid of the present invention may be added in a powder state into the polymerization system of the vinyl-based monomer, or as an aqueous liquid (preferably, 30 to 50% by mass of the PVA-based polymer (A)). It may be prepared (as an aqueous solution) before use. Further, the dispersion aid of the present invention can be dissolved in a water-soluble organic solvent, a mixed solvent of water and a water-soluble organic solvent, or the like and added to the polymerization system. Further, the dispersion aid of the present invention may be charged in the polymerization system when or after the vinyl-based monomer is charged in the polymerization system, but the polymerization system may be charged before the vinyl-based monomer is charged in the polymerization system. It is preferable to prepare it inside.

The polymerization initiator is not limited, and may be oil-soluble, for example, a percarbonate compound such as diisopropylperoxydicarbonate, di-2-ethylhexyl peroxydicarbonate, or diethoxyethylperoxydicarbonate. t-Butylperoxyneodecanoate, t-hexylperoxyneodecanoate, t-hexylperoxypivalate, α-cumylperoxyneodecanoate, t-hexylneeohexanoate, 2,4 Peroxyester compounds such as 4-trimethylpentyl-2-peroxy-2-neodecanoate, azo compounds such as azobis (2,4-dimethylvaleronitrile), azobisisobutyronitrile, lauryl peroxide, benzoyl peroxide, etc. Examples thereof include peroxide compounds such as cumene hydroperoxide and 2,4,4-trimethylpentyl-2-peroxyphenoxyacetate.

The polymerization initiator may be added either before or after charging the water or the monomer. Alternatively, it may be added to the polymerization tank after being made into an aqueous emulsion in advance.
The amount of the polymerization initiator added is preferably 0.02 to 0.5 parts by mass with respect to 100 parts by mass of the vinyl monomer or the monomer mixture containing the vinyl monomer.

A known technique can be used for various conditions in the method for producing a vinyl resin of the present invention. For example, the polymerization conditions such as the charging method of each raw material compound, the charging ratio of the monomer and the aqueous solvent, the polymerization temperature, the polymerization conversion rate, and the stirring rotation speed are not particularly limited. Further, if necessary, various known additives such as a defoaming agent, a degree of polymerization adjusting agent, a chain transfer agent, an antioxidant, and an antistatic agent may be used in combination.

[Vinyl resin]
The present invention also includes specific vinyl resins. The method for producing the vinyl-based resin is not particularly limited, but it can usually be produced by the suspension polymerization of the vinyl-based monomer described above.

The vinyl-based resin may contain a PVA-based polymer (A), and the PVA-based polymer (A) may be contained in the polymerized chain of the vinyl-based resin as a polymerization component.
For example, a vinyl-based monomer is suspended-polymerized in the presence of the dispersion-assisting agent of the present invention, and a part of the PVA-based polymer (A) contained in the dispersion-assisted agent is suspended-polymerized together with the vinyl-based monomer. By doing so, a vinyl resin containing the PVA-based polymer (A) as a polymerization component can be produced.

In the vinyl resin, the content of the unit derived from the PVA polymer (A) is not particularly limited, but in terms of the monomers constituting the vinyl resin, for example, 0.001 to 1 mol%, preferably 0.001 to 0.001. It is 0.5 mol%, more preferably 0.005 to 0.2 mol%.

The present invention also includes specific vinyl chloride resins. The method for producing the vinyl chloride-based resin is not particularly limited, but it can usually be produced by the suspension polymerization of the vinyl-based monomer described above.

The optimum value of the vinyl chloride resin differs depending on the application of the vinyl chloride resin, but the amount of dioctylphthalate used as a plasticizer for the vinyl chloride resin is usually 10 parts by mass or more with respect to 100 parts by mass of the vinyl chloride resin. It can absorb 13 to 40 parts by mass, more preferably 15 to 40 parts by mass. A higher amount of plasticizer absorbed is preferable because fish eyes are reduced when a vinyl chloride resin molded product is obtained. However, as the amount of plasticizer absorbed usually increases, the bulk specific gravity decreases. Therefore, when used for rigid vinyl chloride resin applications that do not require a large amount of plasticizer, such as pipe applications and window frame applications, plasticizer absorption The amount does not have to be very high and is preferably 10 parts by mass or more, but when used for soft vinyl chloride resin applications such as sheet and film applications where a large amount of plasticizer needs to be contained, the amount of the plasticizer absorbed is high. It is preferably 20 parts by mass or more. The dispersion aid is mainly used to increase the amount of plasticizer absorbed, and the amount of plasticizer absorbed can be adjusted by increasing or decreasing the amount added. The dispersion aid of the present invention may be used for both hard vinyl chloride resin applications and soft vinyl chloride resin applications. The method for measuring the amount of plasticizer absorbed is not particularly limited, and for example, it can be measured using the method described in Examples described later.

The average particle size of the vinyl chloride resin is, for example, 100 to 200 μm, preferably 110 to 190 μm, and more preferably 120 to 180 μm. The method for measuring the average particle size is not particularly limited, and the average particle size can be measured, for example, by measuring the particle size distribution using a low-tap type vibrating sieve (using a JIS sieve).

The maximum particle size of the vinyl chloride resin is usually 250 μm or less. The amount of particles of the vinyl chloride resin that cannot pass through the JIS standard # 60 sieve is preferably less than 0.1% by mass. The particle size distribution of the vinyl chloride resin is preferably in the range of 60 to 250 μm.
Further, in the vinyl chloride resin, the amount of particles passing through the JIS standard # 250 sieve is preferably less than 0.1% by mass.
The method for measuring the maximum particle size and the particle size distribution is not particularly limited, and can be measured, for example, by measuring the particle size distribution using a low-tap type vibrating sieve (using a JIS sieve).

The bulk specific gravity (bulk density) of the vinyl chloride resin is, for example, 0.35 to 0.65 g / ml, preferably 0.4 to 0.6 g / ml, and more preferably 0.5 to 0.6 g / ml. ..
The bulk specific gravity is preferably high because the extrusion speed can be improved. The bulk specific gravity can be measured according to JIS K 6721.

The vinyl chloride-based resin of the present invention has excellent characteristics such as no coarse particles, an excellent amount of plasticizer absorbed, a high porosity, and less occurrence of fish eyes.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.
In the following Examples and Comparative Examples, "%" and "parts" mean "mass%" and "parts by mass" unless otherwise specified.

First, the method for evaluating the characteristics of the aqueous liquid and the vinyl chloride resin (vinyl chloride resin) in this example is shown below.

(Characteristic evaluation of aqueous liquid)
The stability, viscosity, fluidity and denaturation stability of the obtained aqueous liquid were confirmed and measured by the following methods, respectively.
a) Stability: 200 g of an aqueous solution was placed in a 200 ml tall biker and left at 25 ° C. for one day, and then the state was visually observed.
◯: Uniform (without precipitation or phase separation), ×: Non-uniform (with precipitation or phase separation)
b) Viscosity: The viscosity of the aqueous liquid at 20 ° C. was measured using a B-type rotational viscometer.
c) Fluidity: The fluidity of the aqueous solution was evaluated according to the following criteria.
◯: Viscosity = less than 5000 mPa · s, ×: Viscosity = 5000 mPa · s or more d) pH: The aqueous liquid was measured at 20 ° C. according to the measuring method specified by JISZ8802.
e) Stability of modified amount: After storing the obtained aqueous solution at room temperature for 1 month, the degree of modification of the monoaldehyde having an olefin-based unsaturated double bond was measured and compared with the value immediately after the production of the aqueous solution.
◯: Change in modification amount is less than 10% of the degree of modification immediately after the production of the aqueous solution ×: Change in the amount of modification is 10% or more of the degree of modification immediately after the production of the aqueous solution

(Evaluation of vinyl chloride resin)
The average particle size, scale adhesion amount, coarse particle content, bulk specific gravity, plasticizer absorbency, and fish eye were evaluated for the vinyl chloride resin as follows.

<Average particle size, coarse particle content>
The particle size distribution was measured with a low-tap type vibrating sieve (using a JIS sieve), and the average particle size was determined.
The average particle size of the vinyl chloride resin is generally 100 μm to 200 μm.
From the measured particle size distribution, the content of coarse particles of 60 mesh-on (that is, particle size of 250 μm or more) was expressed in%. The smaller the content, the smaller the number of coarse particles and the sharper the particle size distribution, indicating that the polymerization stability is excellent. In Tables 2 and 3 described later, the content is shown as # 60 on.

<Amount of scale adhered>
After the polymer slurry was taken out from the polymerization tank, the state of scale adhesion on the inner wall of the polymerization tank was visually observed and evaluated according to the following criteria.
⊚: Almost no scale adhesion Δ: Adhesion to the extent that the scale can be visually recognized ×: White scale adhesion is remarkable

<Bulk specific gravity>
Measured according to JIS K6721. The larger the bulk specific gravity, the higher the extrusion speed and the better the workability.

<Plasticizer absorbency>
Put the obtained resin in a cylindrical container filled with glass fiber at the bottom, add excess dioctyl phthalate (hereinafter abbreviated as DOP), leave it for 30 minutes to allow DOP to permeate the resin, and then at 3000 rpm. After removing excess DOP by centrifugation, the weight of the resin was measured to calculate the amount of DOP absorbed per 100% by mass of the polymer. The larger the DOP absorption amount, the larger the porosity, the better the plasticizer absorption, and the better the molding processability. Further, the higher the plasticizer absorbency, the higher the porosity of the vinyl chloride polymer.

<Fish eye>
100 parts by mass of the obtained resin, 30 parts by mass of dioctyl phthalate, 1 part by mass of lead tribasic sulfate, 1.5 parts by mass of lead stearate, 0.2 parts by mass of titanium dioxide, and 0.1 part by mass of carbon black were added at 150 ° C. A sheet having a thickness of 0.3 mm was prepared by melt-kneading for 3 minutes, and the number of fish eyes (transparent particles of 0.4 mm or more) per 100 mm × 100 mm was visually measured. The amount of fish eyes is preferably small because it is a drawback of the molded product.

<Example 1>
(Synthesis of PVA-based polymer (B))
In a reaction vessel equipped with a stirrer, a condenser, a nitrogen gas inlet and an initiator inlet, 10 parts by mass of vinyl acetate, 67 parts by mass of methanol and 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile) were placed in advance. ) 0.02 parts by mass was charged into a polymerization can, and after nitrogen substitution, the temperature was raised to the boiling point. Then, 140 parts by mass of vinyl acetate was continuously added dropwise from the upper part of the polymerization can little by little over 13 hours. One hour after the completion of the dropping, the system was cooled when the polymerization rate reached 95%, and the polymerization was stopped.
Next, unreacted vinyl acetate was removed by a conventional method, and the methanol content was adjusted so that the concentration of polyvinyl acetate was 60%. To 100 parts by mass of the obtained polyvinyl acetate 60% methanol solution, 3 parts by mass of a 45% methanol solution of p-toluenesulfonic acid was added as a saponification catalyst and mixed well, and the saponification reaction was carried out at 50 ° C. to water. 6.5 parts by mass of a 5% methanol solution of sodium oxide was added to neutralize and the saponification reaction was stopped to obtain a solution of the PVA-based polymer (B). When the obtained solution was dried and analyzed, the saponification degree was 53.0 mol%, the average degree of polymerization was 230, and the block character was 0.70.

(Synthesis of PVA-based polymer (A))
To 100 parts by mass of the solution of the PVA-based polymer (B) obtained above, 2 parts by mass of water was added, and 0.35 parts by mass of achlorine was further added and mixed well, and then 1 mass of a 45% methanol solution of paratoluenesulfonic acid was added. Parts were added and the reaction was carried out at a temperature of 40 ° C. for 30 minutes. Then, a 5% aqueous sodium hydroxide solution was added until the pH of the system reached 7.1 to neutralize. Then, it was dried at 100 ° C. for 2 hours using a vacuum dryer to obtain a PVA-based polymer (A). The analytical values of this PVA-based polymer (A) were a saponification degree of 55.3 mol%, a degree of polymerization of 230, and a block character of 0.70. ^{Moreover, when 1} H-NMR measurement was carried out by dissolving it in d6-DMSO solvent, a signal derived from a double bond was observed at 5.8, 5.4 and 5.2 ppm. The amount of acrolein modified to the PVA-based polymer (A) determined from this signal intensity was 0.9 mol%.
Table 1 shows a summary of the production conditions of the PVA-based polymer (A) and the analysis results.

(Creation of aqueous liquid)
The PVA-based polymer (A) obtained as described above is put into water so as to contain 40% by mass as a solute, dissolved by stirring at 80 ° C. for 1 hour, and cooled to room temperature to dissolve the aqueous liquid. Got The evaluation results of the obtained aqueous liquid are shown in Table 1.
The pH of the obtained aqueous solution was 5.7. In addition, there was no precipitation or phase separation of the aqueous liquid, the fluidity was good, and the change in the amount of denaturation after the aqueous liquid was stored at room temperature for 1 month was less than 10%.

(Suspension polymerization of vinyl chloride (1) -formulation with a small proportion of dispersion aid used)
Using the aqueous solution of the PVA-based polymer (A) obtained above as a dispersion aid, suspension polymerization of vinyl chloride was carried out under the conditions shown below.
In a polymerization machine (pressure resistant autoclave) with an internal volume of 100 liters, 112.5 parts by mass of deionized water, 0.06 parts by mass of partially saponified polyvinyl alcohol (80 mol% saponification degree, 2500 degree of polymerization), partially saponified polyvinyl 0.02 parts by mass of alcohol (saponification degree 72 mol%, polymerization degree 800) was dissolved and charged. Further, 0.0625 parts by mass (0.025 parts by mass as the PVA-based polymer (A)) of the aqueous liquid of the present invention obtained above (content of PVA-based polymer (A) is 40%) was charged, and further. 0.05 parts by mass of t-butylperoxyneodecaate was added. Next, after degassing the inside of the polymerization machine to 40 mmHg, 100 parts by mass of a vinyl chloride monomer was charged and stirring was started. The polymerization temperature was 57 ° C., and this temperature was maintained until the completion of polymerization. The aqueous liquid of the present invention was used after being stored at room temperature for 1 month or longer.
The reaction was terminated when the polymerization conversion rate reached 80%, the unreacted monomer in the polymerization machine was recovered, and then the polymer slurry was taken out of the system and dehydrated and dried to obtain a vinyl chloride resin. The evaluation results of the vinyl chloride resin are shown in Table 2.

(Suspension polymerization of vinyl chloride (2) -formulation with a large proportion of dispersion aids used)
Using the aqueous solution of the PVA-based polymer (A) obtained above as a dispersion aid, suspension polymerization of vinyl chloride was carried out under the conditions shown below.
In a polymerizer (pressure resistant autoclave) with an internal volume of 100 liters, 112.5 parts by mass of deionized water, 0.04 parts by mass of partially saponified polyvinyl alcohol (80 mol% degree of polymerization, 2500 degree of polymerization), partially saponified polyvinyl An aqueous solution of the present invention obtained by dissolving 0.01 part by mass of alcohol (sakenization degree 72 mol%, polymerization degree 800) and further obtained above (content of PVA-based polymer (A) is 40%). 0.1 part by mass (0.04 part by mass as the PVA-based polymer (A)) was charged, and 0.05 part by mass of t-butylperoxyneodecaate was further added. Next, after degassing the inside of the polymerization machine to 40 mmHg, 100 parts by mass of a vinyl chloride monomer was charged and stirring was started. The polymerization temperature was 57 ° C., and this temperature was maintained until the completion of polymerization. The aqueous liquid of the present invention was used after being stored at room temperature for 1 month or longer.
The reaction was terminated when the polymerization conversion rate reached 80%, the unreacted monomer in the polymerization machine was recovered, and then the polymer slurry was taken out of the system and dehydrated and dried to obtain a vinyl chloride resin. The evaluation results of the vinyl chloride resin are shown in Table 3.

Stable polymerization is possible not only in formulations with a small usage ratio of dispersion aids, but also in formulations with a large usage ratio, there is no scale adhesion, there are no coarse particles, it has a very high porosity, and the amount of plasticizer absorbed. Was very high, and a good vinyl chloride resin with very few fish eyes was obtained. In any of the formulations, the vinyl chloride resin contained the PVA-based polymer (A).

<Examples 2 to 8>
Using the PVA-based polymer (A) synthesized in the same manner as in Example 1 except that the monoaldehyde having an olefin-based unsaturated double bond shown in Table 1 was used, an aqueous solution was prepared in the same manner as in Example 1. Then, suspension polymerization of vinyl chloride was carried out with two formulations in the same manner as in Example 1 to obtain a vinyl chloride resin. The evaluation results of the obtained vinyl chloride resin are shown in Tables 2 and 3.
In all cases, the obtained aqueous liquid was stable with no precipitation and phase separation, had good fluidity, and the change in the amount of denaturation after storing the aqueous liquid at room temperature for 1 month was less than 10%. ..

In addition, in all the examples, stable polymerization can be achieved with either a formulation with a small dispersion aid usage ratio or a formulation with a large dispersion aid usage ratio, especially with a formulation with a large dispersion aid usage ratio, and scale. A good vinyl chloride resin was obtained, which had no adhesion, no coarse particles, a very high porosity, a very high amount of plasticizer absorbed, and a very small amount of fish eyes. In any of the formulations, the vinyl chloride resin contained the PVA-based polymer (A).

<Examples 9 to 12>
The amount of methanol used for the polymerization of vinyl acetate so that the PVA-based polymer (A) having the degree of polymerization, the degree of saponification and the block character shown in Table 1 can be obtained, 2,2'-azobis (4-methoxy-2). , 4-Dimethylvaleronitrile) PVA-based polymer (B) synthesized in the same manner as in Example 1 except that the addition amount, reaction yield, saponification reaction time, and amount of neutralizing agent used were appropriately changed. And, using the PVA-based polymer (A) synthesized in the same manner as in Example 1 using the monoaldehyde having the olefin-based unsaturated double bond shown in Table 1, Table 1 shows in the same manner as in Example 1. An aqueous solution containing the PVA-based polymer (A) shown was prepared, and suspension polymerization of vinyl chloride was carried out with two formulations in the same manner as in Example 1 to obtain a vinyl chloride resin. The evaluation results of the obtained vinyl chloride resin are shown in Tables 2 and 3.
In all cases, the obtained aqueous liquid was stable with no precipitation and phase separation, had good fluidity, and the change in the amount of denaturation after storing the aqueous liquid at room temperature for 1 month was less than 10%. ..
In addition, in all the examples, stable polymerization can be achieved with either a formulation with a small dispersion aid usage ratio or a formulation with a large dispersion aid usage ratio, especially with a formulation with a large dispersion aid usage ratio, and scale. A good vinyl chloride resin was obtained, which had no adhesion, no coarse particles, a very high porosity, a very high amount of plasticizer absorbed, and a very small amount of fish eyes.

<Comparative example 1>
As shown in Table 1, an aqueous solution was prepared in the same manner as in Example 1 except that the PVA-based polymer (A) was used as it was as a dispersion aid instead of the PVA-based polymer (B). In the same manner, suspension polymerization of vinyl chloride was carried out using the two formulations to obtain a vinyl chloride resin.
The evaluation results of the obtained vinyl chloride resin are shown in Tables 2 and 3.
The formulation with a small proportion of the dispersion aid was not so different from the result of Example 1, but the formulation with a large proportion of the dispersion aid did not allow stable polymerization, had scale adhesion, and was coarse. Only vinyl chloride resin, which had particles, had a slightly low porosity and a little low plasticizer absorption, and had a lot of fish eyes, could be obtained.

<Reference Examples 1 and 2>
Using the PVA-based polymer (A) synthesized in the same manner as in Example 1 except that the saponification time was changed so as to have the saponification degree as shown in Table 1, the aqueous polymer (A) was used in the same manner as in Example 1. A liquid was prepared, and suspension polymerization of vinyl chloride was carried out with two formulations in the same manner as in Example 1 to obtain a vinyl chloride resin. The evaluation results of the obtained vinyl chloride resin are shown in Tables 2 and 3.

In Reference Example 1, as shown in Table 1, an attempt was made to obtain a 40% by mass aqueous solution in the same manner as in Example 1, but the saponification degree of the PVA-based polymer (A) was too low at 38.5 mol%. Therefore, the dispersibility in water was poor, and a uniform aqueous liquid could not be obtained. Therefore, the polymerization test of vinyl chloride was not performed.

In Reference Example 2, the degree of saponification of the PVA-based polymer (A) was too high at 66.5 mol%, so that the PVA-based polymer (A) did not have a sufficient effect as a dispersion aid, and Table 2 And as shown in Table 3, regardless of the formulation with a small usage ratio of the dispersion aid or the formulation with a large usage ratio of the dispersion aid, coarse particles are present and uniform polymer particles cannot be obtained, and stable polymerization is achieved with a large amount of scale adhesion. In addition, the porosity and the amount of plasticizer absorbed were not sufficient, and there were many fish eyes, so that a good vinyl chloride resin could not be obtained.

<Reference Examples 3 and 4>
The amount of methanol used for the polymerization of vinyl acetate so that the PVA-based polymer (B) having the degree of polymerization shown in Table 1 can be obtained, of 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile). A PVA-based polymer synthesized in the same manner as in Example 1 except that the PVA-based polymer (B) synthesized in the same manner as in Example 1 was used except that the addition amount and the reaction yield were appropriately changed. Using A), an aqueous solution was prepared in the same manner as in Example 1, and suspension polymerization of vinyl chloride was carried out with two formulations in the same manner as in Example 1 to obtain a vinyl chloride resin. The evaluation results of the obtained vinyl chloride resin are shown in Tables 2 and 3.

In Reference Example 3, the degree of polymerization was too low at 110, so the performance as a dispersion aid was insufficient, and in a formulation with a small proportion of the dispersion aid used, scale adhered, coarse particles were present, and fish eyes were present. Vinyl chloride resin with a large amount of dispersion aid, which cannot be polymerized stably, has scale adhesion, has coarse particles, has a slightly low void ratio and plasticizer absorption, and has many fish eyes. I could only get it.

In Reference Example 4, since the degree of polymerization was too high at 550, the fluidity of the aqueous liquid was very poor as shown in Table 1. Therefore, when it is added to the polymerization tank by suspension polymerization of vinyl chloride, it does not disperse well in the aqueous medium and a sufficient effect cannot be obtained. However, in both formulations with a large proportion of dispersion aids, the obtained vinyl chloride resin has coarse particles and cannot obtain uniform polymer particles, and the amount of scale adhesion is large and stable polymerization is not possible. In addition, the porosity and the amount of plasticizer absorbed were not sufficient, and there were many fish eyes, so that a good vinyl chloride resin could not be obtained.

<Reference example 5>
To obtain the PVA-based polymer (B) having the block character shown in Table 1, the saponification catalyst was 3 parts by mass of a 5% methanol solution of sodium hydroxide, and the neutralizing agent was 0.3 mass by mass of a 5% methanol solution of acetic acid. Example using a PVA-based polymer (A) synthesized in the same manner as in Example 1 except that a PVA-based polymer (B) synthesized in the same manner as in Example 1 was used except that it was changed to a part. An aqueous solution was prepared in the same manner as in Example 1, and suspension polymerization of vinyl chloride was carried out with two formulations in the same manner as in Example 1 to obtain a vinyl chloride resin. The evaluation results of the obtained vinyl chloride resin are shown in Tables 2 and 3.
Since the block character of the PVA-based polymer (A) was as low as 0.47, the fluidity of the aqueous liquid was poor. Therefore, when it is added to the polymerization tank by suspension polymerization of vinyl chloride, it does not disperse well in the aqueous medium and a sufficient effect cannot be obtained. In both the formulation and the obtained vinyl chloride resin, there are coarse particles and uniform polymer particles cannot be obtained, the amount of scale adhesion is large and stable polymerization is not possible, and the porosity and plasticizer The amount of absorption was not sufficient, and there were many fish eyes, so that a good vinyl chloride resin could not be obtained.

<Reference Examples 6 and 7>
The same method as in Example 1 was used, except that the same PVA-based polymer (A) as in Example 1 was used and only the content of the PVA-based polymer (A) was changed as shown in Table 1. An aqueous solution was prepared by the method, and suspension polymerization of vinyl chloride was carried out with two formulations in the same manner as in Example 1 to obtain a vinyl chloride resin. The evaluation results of the obtained vinyl chloride resin are shown in Tables 2 and 3.

In Reference Example 6, since the content of the PVA-based polymer (A) in the aqueous liquid was too low, the stability of the aqueous liquid was poor and separation and precipitation occurred. Therefore, in suspension polymerization of vinyl chloride, when it is added to the polymerization tank, it does not disperse well in water and a sufficient effect cannot be obtained. In both cases, the obtained vinyl chloride resin has coarse particles and cannot obtain uniform polymer particles, has a large amount of scale adhesion, and stable polymerization is not possible, and has a porosity and plasticity. The amount of the agent absorbed was not sufficient, and there were many fish eyes.

In Reference Example 7, since the content of the PVA-based polymer (A) in the aqueous liquid was too high, the fluidity of the aqueous liquid was very poor. Therefore, in suspension polymerization of vinyl chloride, when it is added to the polymerization tank, it does not disperse well in water and a sufficient effect cannot be obtained. In both cases, the obtained vinyl chloride resin has coarse particles and cannot obtain uniform polymer particles, has a large amount of scale adhesion, and stable polymerization is not possible, and the amount of plasticizer absorbed is also high. Not enough and there were many fish eyes.

<Reference example 8>
A PVA-based polymer obtained in the same manner as in Example 1 except that the amount of sodium hydroxide added for neutralizing the acetalization reaction used in an aldehyde having an olefin-based unsaturated double bond was changed to 2.0 parts by mass. Using (A), an aqueous solution was prepared by the same method as described in Example 1, and suspension polymerization of vinyl chloride was carried out with two formulations in the same manner as in Example 1 to obtain a vinyl chloride resin. The evaluation results of the obtained vinyl chloride resin are shown in Tables 2 and 3.
Since the acid catalyst used in the acetalization reaction of the monoaldehyde having an olefin unsaturated double bond was insufficiently neutralized, the pH of the obtained aqueous solution became as low as 2.8 as shown in Table 1. Oops. Therefore, the amount of denaturation of the monoaldehyde having an olefin-based unsaturated double bond after storage at room temperature for one month was 10% or more, which was greatly reduced. Therefore, the effect of the present invention was not sufficiently obtained, and as shown in Table 2, the results obtained in the formulation with a small usage ratio of the dispersion aid were not significantly different from those in Example 1, but as shown in Table 3, the dispersion aid was used. In the formulation with a large usage ratio, the obtained vinyl chloride resin has coarse particles and cannot obtain uniform polymer particles, has a large amount of scale adhesion, and stable polymerization is not possible, and also has a porosity and plasticity. The amount of agent absorbed was not sufficient, and there were many fish eyes.

<Reference Examples 9 to 10>
As shown in Table 1, a PVA-based polymer (A) was synthesized in the same manner as in Example 1 except that an aliphatic dialdehyde was used instead of the monoaldehyde having an olefin-based unsaturated double bond.
In Reference Examples 9 and 10, since the aliphatic dialdehyde was used, the obtained PVA-based polymer was insolubilized, and an aqueous solution could not be obtained as shown in Table 1. Therefore, the polymerization test of vinyl chloride could not be performed. The degree of acetalization was determined from the amount of unreacted aldehyde.

Even when the dispersion aid of the present invention is used in a large amount to obtain a high porosity, a stable and good polymer can be obtained with little scale adhesion to the polymerization tank, and there are no coarse particles, which is very high. It is extremely useful industrially because it is possible to obtain a vinyl chloride-based resin having a porosity and excellent plasticizer absorbability.

Claims (18)

Polyvinyl alcohol-based weight having an acetal group (a) having an olefin-based unsaturated double bond, a degree of saponification of 45 to 58.5 mol%, an average degree of polymerization of 120 to 400, and a block character of 0.5 or more. A dispersion aid for suspension polymerization containing the coalescence (A). Polyvinyl alcohol type having an acetal group (a) having an olefin-based unsaturated double bond, a degree of saponification of 45 to 60 mol%, an average degree of polymerization of 120 to 400, and a block character of 0.6 to 0.9. A dispersion aid for suspension polymerization containing the polymer (A). Polyvinyl having an acetal group (a) having an olefin-based unsaturated double bond, a degree of saponification of 45 to 58.5 mol%, an average degree of polymerization of 120 to 400, and a block character of 0.6 to 0.9. A dispersion aid for suspension polymerization containing an alcohol-based polymer (A). The dispersion aid for suspension polymerization according to any one of claims 1 to 3, wherein the polyvinyl alcohol-based polymer (A) has an average degree of polymerization of 160 to 400. Claims 1 to 4 in which the amount of modification of the unit containing the acetal group (a) in the polyvinyl alcohol-based polymer (A) is 0.01 to 10 mol% per monomer unit of the polyvinyl alcohol-based polymer (A). The dispersion aid for suspension polymerization according to any one. The dispersion aid for suspension polymerization according to any one of claims 1 to 5, which is present in a polymerization system together with a water-soluble polymer to carry out suspension polymerization. The dispersion aid for suspension polymerization according to claim 6 , wherein the water-soluble polymer is a polyvinyl alcohol-based polymer having a saponification degree of 65 to 90 mol%. The dispersion aid for suspension polymerization according to any one of claims 1 to 7 , which is used for polymerizing a vinyl-based monomer. The dispersion aid for suspension polymerization according to claim 8, wherein the vinyl-based monomer contains vinyl chloride. An aqueous solution containing the dispersion aid for suspension polymerization according to any one of claims 1 to 9. The aqueous solution according to claim 10, which contains 30 to 50% by mass of the polyvinyl alcohol-based polymer (A). The aqueous solution according to claim 10 or 11 , which has a pH of 4.5 to 7. A method for producing a vinyl-based resin in which a vinyl-based monomer is suspended-polymerized in the presence of the dispersion aid for suspension polymerization according to any one of claims 1 to 9. The production method according to claim 13 , further comprising suspension polymerization in the presence of a water-soluble polymer. The production method according to claim 14 , wherein the water-soluble polymer is a polyvinyl alcohol-based polymer having a saponification degree of 65 to 90 mol%. The production method according to any one of claims 13 to 15 , wherein the vinyl-based monomer contains vinyl chloride. A vinyl resin containing the polyvinyl alcohol-based polymer (A) according to any one of claims 1 to 5 as a polymerization component. The vinyl-based resin according to claim 17, which is a vinyl chloride-based resin.