JP7064318B2 - Polyvinyl alcohol resin and its manufacturing method - Google Patents

Description

The present invention relates to a novel polyvinyl alcohol resin (polyvinyl alcohol-based polymer) and a method for producing the same.

Polyvinyl alcohol (hereinafter abbreviated as PVA) is a hydrophilic synthetic resin, which is a polymerization suspending agent for vinyl chloride resin, a polarizing film, a raw material for butyral resin used as an interlayer film for laminated glass of automobiles, and a photosensitive printing plate. Raw materials for, fiber processing agents, paper surface sizing agents, emulsifying dispersants for emulsifying and polymerizing adhesives such as vinegar biemulsion and ethylene-vinegar biemulsion in water system, raw materials for vinylon fiber, water-soluble film, medical use It is used for various purposes such as binders for tablets such as oral medicines and coating agents.

PVA is mostly used as an aqueous solution, but the method of dissolving it in water is extremely complicated, and it cannot be completely dissolved without a dissolution facility dedicated to PVA.

As a method for dissolving PVA in water, for example, by gradually adding PVA to agitated cold water at 5 to 25 ° C., first, each PVA particle is dispersed in water so as to be separated. Then, there is a method of heating and dissolving at about 90 ° C. by raising the temperature while stirring.
As described above, in the dissolution of PVA, lumps (lumps) such as mamaco and dumplings are formed unless the dispersion procedure is surely carried out.

In addition, since PVA cannot be directly added to hot water at 40 to 100 ° C. for dissolution, not only does it require a long dissolution time, but it is also necessary to cool the dissolution tank once after dissolution, so that the dissolution operation is continuously performed. There was a problem such as not being able to do it.

The cause of the occurrence of such mamaco is that when PVA is put into water, the surface of the PVA particles immediately swells in the water and becomes semi-dissolved, and the PVA particles adhere to each other to form a large mass. Conceivable.

Once such a lump is formed, even if it is heated and stirred for a long time after that, the surface of the lump is only slightly dissolved and undissolved residue is formed, so that it cannot be completely dissolved.

In particular, when PVA is put into high-temperature water of 40 ° C. or higher, the degree of sacrifice of PVA is low (especially 90 mol% or less), the degree of polymerization is high (especially 1700 or higher), and the dissolution concentration is high. (For example, 10 to 20% or more), or when the PVA particles are fine, only the surface part of the lumpy substance is dissolved and the inside is liable to become a "dama" with no water permeation. , It becomes extremely difficult to dissolve.

Attempts are being made to improve such solubility. For example, Patent Document 1 discloses a method for improving solubility in PVA having a specific particle size distribution.

Further, Patent Document 2 discloses a method for facilitating dispersion and dissolution by having pores of 0.1 to 10 μm inside the PVA powder at a ratio of 0.05 to 0.4 cc / g.

However, in the methods described in these documents, only specific PVA can be used, and complicated operations are required. Therefore, it cannot be said that it is suitable as PVA as an industrial product.

Japanese Unexamined Patent Publication No. 2000-265026 Japanese Unexamined Patent Publication No. 9-316272

An object of the present invention is to provide a novel polyvinyl alcohol resin.

Another object of the present invention is to provide a polyvinyl alcohol resin having excellent solubility or dispersibility.

Still another object of the present invention is to provide a method for producing a polyvinyl alcohol resin as described above.

As a result of diligent research, the present inventor has been able to improve solubility or dispersibility by containing a surfactant in a polyvinyl alcohol resin (hereinafter, may be simply referred to as PVA resin, PVA, etc.). The present invention was completed after further diligent studies.

That is, the present invention relates to the following inventions and the like.
[1]
Polyvinyl alcohol resin containing a surfactant.
[2]
The resin according to [1], wherein the polyvinyl alcohol resin has a degree of polymerization of 500 or more.
[3]
The resin according to [1] or [2], wherein the polyvinyl alcohol resin has a saponification degree of 97 mol% or less and a polymerization degree of 1500 or more.
[4]
The resin according to any one of [1] to [3], wherein the surfactant comprises at least one selected from anionic surfactant and nonionic surfactant.
[5]
The resin according to any one of [1] to [4], wherein the ratio of the surfactant is 5% by mass or less.
[6]
The resin according to any one of [1] to [5], wherein the ratio of the surfactant is 1% by mass or less.
[7]
The resin according to any one of [1] to [6], wherein the surfactant contains a nonionic surfactant and the proportion of the surfactant is 0.0001 to 0.1% by mass.
[8]
The resin according to any one of [1] to [7], which is a resin particle that passes through a 10-mesh sieve.
[9]
The method for producing a resin according to any one of [1] to [8], wherein the polyvinyl alcohol resin and the surfactant are mixed.
[10]
The production method according to [9], wherein the polyvinyl alcohol resin is mixed with a mixed solution of a surfactant and a solvent.
[11]
The production method according to [10], wherein the solvent is a mixed solvent of water and alcohols.

The present invention can provide a novel polyvinyl alcohol resin.
Such a polyvinyl alcohol resin contains a surfactant and is excellent in solubility or dispersibility in water or the like.

In the present invention, unlike Patent Documents 1 and 2, it is not necessary to use a special polyvinyl alcohol resin, a general polyvinyl alcohol resin can be used, and the versatility is high.

Further, if the polyvinyl alcohol resin contains a foreign substance, it cannot be applied to applications that dislike the foreign substance, and the application may be greatly restricted. For example, depending on the type of foreign matter, it may be possible to use it only for a limited purpose such as washing glue.
On the other hand, in the present invention, a small amount of the surfactant is added to the polyvinyl alcohol resin (for example, 1 part by mass or less, 0.5 part by mass or less, 0.1 part by mass with respect to 100 parts by mass of the polyvinyl alcohol resin). Excellent solubility or dispersibility can be achieved by simply adding (in a ratio such as the following).
Therefore, the polyvinyl alcohol resin of the present invention can be applied not only to applications that dislike foreign substances but also to a wide range of applications or general applications.

The present invention can provide a method for producing the above-mentioned polyvinyl alcohol resin. In particular, in such a method, it can be contained by a simple method such as adding a surfactant.
As described above, the polyvinyl alcohol resin of the present invention is highly versatile, including its manufacturing method.

More specifically, the polyvinyl alcohol resin of the present invention has excellent solubility or dispersibility, and a liquid containing a PVA-based resin (particularly, a solution or dispersion containing at least water) can be easily prepared and is easy to handle. It is an excellent material.

The polyvinyl alcohol resin of the present invention is used as a reaction raw material and has various uses (for example, a polymerization suspending agent for vinyl chloride resin and a polarization used for a TV or a personal computer display) in which impurities are disliked. Raw materials for butyral resin used for films and interlayers of laminated glass for automobiles, raw materials for photosensitive printing plates, fiber processing agents, paper surface sizing agents, adhesives such as vinegar biemulsion and ethylene-vinegar biemulsion. It can be used without limitation even with an emulsifying dispersant for emulsifying and polymerizing in an aqueous system, a raw material for vinylon fiber, a water-soluble film, a binder for tablets such as oral medical drugs, and a coating agent).

In particular, a urea admixture that is directly charged as PVA powder in a high-temperature solution during a urea resin synthesis reaction or immediately after an emulsion polymerization reaction, a viscosity modifier for adding an emulsion, and PVA powder in a high-temperature solution during vinyl chloride suspension polymerization. It can be suitably used because PVA can be dissolved without becoming mamaco even by a method such as charging.

Further, in the case of producing a PVA film by an aqueous solution casting method, the concentration of the PVA aqueous solution is higher because the time and energy for drying and removing the water in the subsequent drying step are shorter when the concentration of the PVA aqueous solution is increased. It may be set as very high as 20 to 50%. When preparing such a high-concentration aqueous solution, the PVA added at the initial stage is gradually dissolved in order to charge a large amount of PVA into water, and the concentration and viscosity increase. Mamako is more likely to occur. Even in such a case, the PVA of the present invention does not produce mamaco and can be suitably used.

When dissolving PVA in water, lumps are likely to occur when the water temperature is high, the PVA powder is directly charged into a high-temperature reaction, the stirring capacity of the dissolution equipment is low, and high-concentration dissolution is performed. The PVA of the present invention can be suitably used even in such a case.

Further, since PVA of the present invention is difficult to form mamaco, PVA can be easily dissolved without a stirring facility, so that it can be suitably used for laundry glue used at home or a cement admixture used outdoors. ..

In the past, in order to use PVA for each purpose, it was usually carefully added in small amounts to cold water and dispersed by heating and then dissolved. Since the PVA aqueous solution can be adjusted, the dissolution work can be performed simply in a short time, and the productivity can be dramatically improved.

[Polyvinyl alcohol resin]
The polyvinyl alcohol resin (composition) of the present invention is composed of a polyvinyl alcohol resin (a base polyvinyl alcohol resin) and a surfactant.
Therefore, the polyvinyl alcohol resin (composition) of the present invention can also be said to be a composition (resin composition) containing a polyvinyl alcohol resin and a surfactant.

(Polyvinyl alcohol resin)
The polyvinyl alcohol resin (PVA, PVA resin) is usually a saponified product of a vinyl ester polymer (a polymer containing vinyl ester as a polymerization component).

The vinyl ester polymer contains at least vinyl ester as a polymerization component. The vinyl ester (vinyl ester-based monomer) is not particularly limited, and is, for example, a fatty acid vinyl ester [for example, vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl caprylate, vinyl versatic acid, vinyl monochloroacetate. C _1-20 fatty acid vinyl esters such as (eg, C _1-16 alkanoic acid-vinyl ester)], aromatic carboxylic acid vinyl esters [eg, allene carboxylic acid vinyl such as vinyl benzoate (eg C _7-12 ) Allene carboxylic acid-vinyl ester), etc.] and the like.

Vinyl esters may be used alone or in combination of two or more.

The vinyl ester preferably contains at least a fatty acid vinyl ester (for example, C _1-10 alkanoic acid-vinyl ester such as vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, etc.), and from an industrial point of view, it is preferable. In particular, vinyl acetate may be contained.

The polymerization component (polymerization component of the vinyl ester polymer) may contain at least vinyl ester, and may contain other monomers (monomers that can be copolymerized with vinyl ester), if necessary. Good (may be modified with other monomers).

The other monomer is not particularly limited, but is, for example, α-olefins (eg, ethylene, propylene, etc.), (meth) acrylic acid esters [eg, (meth) methyl acrylate, (meth) acrylic acid. (Meta) acrylic acid alkyl esters such as ethyl, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate], unsaturated amides [eg, (meth) acrylamide, diacetone acrylamide, N-methylol acrylamide, etc.] , Unsaturated acids {eg, unsaturated acids [eg, (meth) acrylic acid, crotonic acid, maleic acid, itaconic acid, fumaric acid, etc.], unsaturated acid esters [unsaturated acid esters other than (meth) acrylic acid, For example, alkyl (methyl, ethyl, propyl, etc.) esters, etc.], unsaturated acid anhydrides (maleic acid anhydride, etc.), unsaturated acid salts [eg, alkali metal salts (eg, sodium salts, potassium salts, etc.), ammonium. Salts, etc.], etc.}, glycidyl group-containing monomers [eg, allyl glycidyl ether, glycidyl (meth) acrylate, etc.], sulfonic acid group-containing monomers (eg, 2-acrylamide-2-methylpropanesulfonic acid, salts thereof, etc.] Etc.), acid group-containing monomers [eg, acid phosphooxyethyl (meth) acrylate, acid phosphooxypropyl (meth) acrylate, etc.], vinyl ethers (eg, alkyl vinyl ethers), allyl alcohol, etc. , In particular, but not limited to these.

Other monomers may be used alone or in combination of two or more.

The polyvinyl alcohol resin (vinyl ester polymer) may have a carbonyl group. Such a polyvinyl alcohol resin having a carbonyl group can be introduced into a copolymer by allowing aldehydes (for example, acetaldehyde, etc.) to coexist in the vinyl ester polymerization.
The polyvinyl alcohol resin having a carbonyl group can be used for PVC suspension polymerization and the like.

Further, in the polyvinyl alcohol resin, a part of the vinyl alcohol unit may be acetalized (formalized, butyralized, etc.). Specifically, it is also possible to react a polyvinyl alcohol resin with butyraldehyde, formaldehyde, or the like to modify a part of the vinyl alcohol into a butyral resin, a formal resin, or the like.

The degree of sacrifice of the polyvinyl alcohol resin can be selected depending on the use of the water-soluble and water-dispersible range of the degree of sacrifice, and is not particularly limited, but is, for example, 10 mol% or more (for example, 15 mol% or more), preferably. 20 mol% or more (for example, 25 mol% or more), more preferably 30 mol% or more (for example, 35 mol% or more), 40 mol% or more (for example, 45 mol% or more), 50 mol% or more (for example, 55 mol% or more). It may be 60 mol% or more (for example, 65 mol% or more), 70 mol% or more (for example, 75 mol% or more), and the like.

The degree of saponification of the polyvinyl alcohol resin is, for example, 100 mol% or less (for example, 99.9 mol% or less), 99.8 mol% or less, 99.7 mol% or less, 99.6 mol% or less, 99.5 mol. % Or less, 99 mol% or less, 98 mol% or less, 97 mol% or less, 96 mol% or less, 95 mol% or less, 94 mol% or less, 93 mol% or less, 92 mol% or less, 90 mol% or less, 89 mol % Or less, 88 mol% or less, 87 mol% or less, 86 mol% or less, 85 mol% or less, and the like.

An appropriate range may be set by appropriately combining these numerical values (for example, 10 to 99.8 mol%, 40 to 90 mol%, etc., the same applies to the description of the numerical values below).

In the present invention, good solubility or dispersibility can be obtained even with a polyvinyl alcohol resin having a relatively low saponification degree.

The degree of saponification is not particularly limited, but may be measured by, for example, the method specified in JIS K 6726.

The degree of polymerization (average degree of polymerization) of the polyvinyl alcohol resin can be selected depending on the intended use and is not particularly limited, but is, for example, 100 or more (for example, 120 or more), preferably 150 or more, and more preferably 200 or more. It may be 300 or more, 400 or more, 500 or more, 600 or more, 700 or more, 800 or more, 1000 or more, 1200 or more, 1500 or more, and the like.

The degree of polymerization (average degree of polymerization) of the polyvinyl alcohol resin is, for example, 10,000 or less (for example, 9000 or less), 8000 or less, 7000 or less, 6000 or less, 5000 or less, 4000 or less, 3000 or less, 2000 or less, 1500 or less, 1000 or less. , 800 or less, 700 or less, 600 or less, 500 or less, 400 or less, and the like.

Polyvinyl alcohol resins having a relatively high degree of polymerization (500 or more, especially 1500 or more) often have extremely poor solubility or dispersibility due to remarkable generation of mamaco, but in the present invention, such relatively high degree of solubility is achieved. Even with a polyvinyl alcohol resin having a degree of polymerization, good solubility or dispersibility can be obtained.

The degree of polymerization is not particularly limited, but may be measured by, for example, the method specified in JIS K 6726.

The viscosity of the 4% aqueous solution of the polyvinyl alcohol resin may be, for example, 2 mPa · s or more, preferably 3 mPa · s or more, more preferably 5 mPa · s or more, 10 mPa · s or more, 20 mPa · s or more, 50 mPa · s. It may be s or more.

The viscosity of the 4% aqueous solution of the polyvinyl alcohol resin may be, for example, 1000 mPa · s or less, 500 mPa · s or less, 200 mPa · s or less, 100 mPa · s or less, 50 mPa · s or less, 30 mPa · s or less.

The viscosity of the 4% aqueous solution is not particularly limited, but may be measured by, for example, the method specified in JIS K 6726.

(Surfactant)
Surfactants are usually amphipathic and often have a hydrophilic group (site) and a lipophilic group (site).
Such a surfactant is not particularly limited and may be any of an ionic surfactant (anionic surfactant, a cationic surfactant), a nonionic surfactant and the like, but in particular, Anionic surfactants and nonionic surfactants may be preferably used.

Examples of the anionic surfactant include a carboxylic acid type surfactant [for example, a carboxylic acid or a salt thereof (for example, a fatty acid salt such as potassium laurate, sodium myristate, sodium cocoyl glutamate), and a sulfo group-containing carboxylic acid ester. Or a salt thereof (eg, alpha sulfo fatty acid methyl ester salt, etc.)], a sulfate ester type surfactant [eg, a sulfate ester or a salt thereof (eg, an alkyl ester sulfate such as octyl sulfate or a salt thereof), etc.], a sulfonic acid. Type surfactant [eg, alkylarene sulfonic acid or a salt thereof (eg, alkylbenzene sulfonic acid such as dodecylbenzene sulfonic acid or a salt thereof), allene sulfonic acid or a salt thereof (eg, allene mono such as trisodium naphthalenetrisulfonate). Or polysulfonic acid or a salt thereof)] and the like.

Examples of the nonionic surfactant include ether type surfactants [for example, alkyl ether type surfactants (for example, polyoxyethylene lauryl ether, polyoxyethylene oleyl ether, polyoxyethylene polyoxypropylene lauryl ether, pentaethylene). Polyoxyalkylene alkyl ethers such as glycol monododecyl ethers), alkylaryl ether type (eg alkylphenyl ether type) surfactants (eg polyoxyethylene octylphenyl ethers, polyoxyalkylene alkyls such as polyoxyethylene alkyl phenyl ethers) Aryl ether), alkenylaryl ether type (eg, allylphenyl ether type) surfactants (eg, polyoxyalkylene allylaryl ethers such as polyoxyalkylene allylphenyl ether), etc.], ester type surfactants [eg, aliphatic Ether (eg, alkyl ester) type surfactant (eg, alkyl alcohol ethoxylate, higher alcohol propoxylate, alkyl alcohol ethoxylate propoxylate, polyoxyethylene laurate, glycerin monostearate, sucrose fatty acid ester, sorbitan fatty acid ester) Mono or polyol fatty acid esters such as)], amine-type (eg, alkylamine-type) surfactants (eg, polyoxyalkylene aliphatic amines such as polyoxyethylene laurylamino ether), amide-type (eg, alkylamides). Type) Surface active agent [eg, polyoxyalkylene fatty acid amide (eg, polyoxyethylene lauric acid amide, etc.)], alkanolamide type surfactant (eg, oleic acid diethanolamide, stearic acid diethanolamide, etc.), polypropylene glycol Ether-type surfactants [eg, polyoxyethylene polyoxypropylene glycol, polyoxyethylene polyoxypropylene ether (eg, alkyl ethers such as polyoxyethylene polyoxypropylene lauryl ether)], higher alcohols (eg, oleyl alcohol, etc.) Stearyl alcohol, etc.) and the like.

Surfactants may be expressed (or classified) as defoamers, emulsifiers, dispersants, penetrants, etc., depending on the intended use, but in the present invention, any of these (any of these uses). (Surfactant) can also be used.

Further, the surfactant may be a commercially available product, and such a commercially available product may contain other components (mineral oil, silica, etc.) or a portion thereof depending on the intended use.

The surfactant may be used alone or in combination of two or more.

In the present invention, at least one surfactant selected from anionic surfactants and nonionic surfactants may be preferably used, and in particular, at least nonionic surfactants [eg, ether type (alkyl). Ether type, etc.), polypropylene glycol ether type, etc.] may be used. The nonionic surfactant does not react with or adsorbs to PVA, or is difficult to adsorb, so that it is easy to obtain excellent solubility or dispersibility of PVA resin even in a small amount.

The content (ratio, amount of use) of the surfactant is not particularly limited, but is in the range of about 0.0001% by mass or more (for example, 0.0002% by mass or more) with respect to the polyvinyl alcohol resin (total). It may be selected, for example, 0.0005% by mass or more (for example, 0.0007% by mass), preferably 0.001% by mass or more (for example, 0.002% by mass or more), and more preferably 0.003% by mass. % Or more (for example, 0.004% by mass or more), 0.005% by mass or more (for example, 0.006% by mass or more), 0.007% by mass or more (for example, 0.008% by mass or more). ), 0.01% by mass or more.

The content of the surfactant is 20% by mass or less (for example, 18% by mass or less), 15% by mass or less, 10% by mass or less, 8% by mass or less, and 7% by mass or less with respect to the polyvinyl alcohol resin (total). , 6% by mass or less, 5% by mass or less, 4% by mass or less, 3.5% by mass or less, 3% by mass or less, 2% by mass or less, 1.5% by mass or less, 1.2% by mass or less, 1% by mass Hereinafter, it may be 0.8% by mass or less.

In particular, the content of the surfactant is 0.5% by mass or less (for example, 0.001 to 0.5% by mass), preferably 0.1% by mass or less (for example, for example) with respect to the PVA resin (total). 0.001 to 0.1% by mass), more preferably 0.05% by mass or less (for example, 0.0005 to 0.05% by mass), particularly 0.01% by mass or less (for example, 0.001 to 0% by mass). It may be about 01% by mass, 0.002 to 0.01% by mass, 0.005 to 0.01% by mass, etc.).

In the present invention, as described above, since solubility or dispersibility can be realized even in a relatively small amount, the composition and physical properties of the PVA resin are hardly changed, and the PVA resin can be used without any influence in any application. Therefore, it is preferable.

The content of the surfactant "X% by mass" may be the same as "X% by mass" in proportion to 100 parts by mass of the polyvinyl alcohol resin. For example, the content of the surfactant "0.1% by mass" may be the same as "0.1% by mass" with respect to 100 parts by mass of the polyvinyl alcohol resin (base polyvinyl alcohol resin).

In the PVA resin (composition) of the present invention, the content form of the surfactant is not particularly limited, but in particular, the interface is on at least the surface (or surface layer) of the base PVA resin (particularly the particulate PVA resin). It may be in the form in which the activator is present.

The PVA resin (or the base PVA resin) may usually be in the form of particles. The particulate PVA resin (PVA resin particles) is not particularly limited, and any shape and particle size such as fine powder, granules, powder, and coarse particles can be used.

In particular, the PVA resin particles are sieves of 10 mesh (# 10) or less (for example, 10 mesh, 14 mesh, 20 mesh, 30 mesh, 32 mesh, 42 mesh, 50 mesh, 60 mesh, 70 mesh, 100 mesh, etc.). It may be resin particles (or resin particles having a particle size of 10 mesh or less) that pass through the above. With such fine particles, the effect of improving dispersibility or solubility becomes more remarkable, and the effect of shortening the dissolution time becomes more remarkable.
The finer the PVA resin particles, the easier it is to improve the dispersibility or solubility by increasing the amount of the surfactant added.

(Production method)
The PVA resin of the present invention (PVA resin containing a surfactant) contains a surfactant in the PVA resin (in particular, it is contained so that the surfactant is present on the surface or surface layer of the PVA resin (particles)). Can be manufactured by.

As the PVA resin, a commercially available product may be used, or a synthetic one may be used.

The PVA resin is obtained by saponifying a vinyl ester polymer (including a copolymer) obtained by polymerizing vinyl esters such as vinyl acetate by various polymerization methods (solution, lump, suspension, emulsion polymerization, etc.). Obtainable.

The polymerization catalyst (polymerization initiator) used for polymerization or copolymerization can be selected depending on the polymerization method and the like. For example, 2-ethylhexyl peroxydicarbonate (Trigonox EHP), 2,2'-azobisisobuty. Lonitrile (AIBN), t-butylperoxyneodecanoate, bis (4-t-butylcyclohexyl) peroxydicarbonate, di-n-propylperoxydicarbonate, di-n-butylperoxydicarbonate, di-cetylperoxy Any initiator capable of generating free radicals, such as dicarbonate and di-s-butylperoxydicarbonate, can be used.

Further, in the step of saponifying a part or all of the obtained vinyl ester polymer, for example, there are a method of directly saponifying in the presence of a saponification catalyst and a method of alcoholizing in an organic solvent.
Examples of the saponification catalyst include alkaline catalysts such as caustic soda, caustic potash, sodium alcoholate, amines and sodium carbonate, and acid catalysts such as sulfuric acid, phosphoric acid and hydrochloric acid, preferably alkaline catalysts, more preferably caustic soda. It is suitable because of its high speed and excellent productivity.

Alcohol is preferable as the organic solvent. Examples of the alcohol include methanol, ethanol, propanol, ethylene glycol, propylene glycol, glycerin, diethylene glycol and the like, and among them, methanol is generally used industrially.

The method for saponifying the vinyl ester polymer is not particularly limited, and for example, a method of adding and mixing a saponification catalyst to a solution of the vinyl ester polymer, a method of adding and mixing a saponification catalyst to a system in which the vinyl ester polymer is dispersed, and the like. In either method, the saponification reaction can be carried out in an anhydrous system or a water-containing system. The saponification reaction can either saponify only part of the ester or completely saponify it. Further, it is also possible to add benzene or another solvent to the saponification solvent by a known method to arrange the vinyl alcohol units in a block shape or a random shape.

The saponified product of the vinyl ester polymer obtained by saponifying a part or all of the vinyl ester of the vinyl ester polymer is, for example, subjected to post-treatment such as neutralization, precipitation, washing, and filtration, if necessary, and then heated, reduced pressure, etc. It may be dried by the method of the above and obtained in the form of powder or granules.

Examples of the method for producing PVA, which is mainly carried out industrially, include the following methods.
First, vinyl acetate or vinyl acetate and various monomers are solution-polymerized in a lower alcohol solvent such as methanol using a radical polymerization initiator to obtain a polymerization reaction solution of a polyvinyl acetate copolymer. The obtained polymerization reaction solution is brought into contact with the vapor of a lower alcohol such as methanol to remove unreacted vinyl acetate and monomers. Next, a saponification catalyst such as caustic soda is added and mixed with the polymerization reaction solution from which this monomer has been removed (demonomerized) to obtain a slurry-like saponification product in which a solid solution is mixed, and excess caustic soda is neutralized.
A slurry of saponification containing PVA, methanol, and a by-product of the saponification reaction (methyl acetate, sodium acetate, etc.) is cut, crushed, and the solid and liquid are separated and filtered by a centrifuge, etc. to separate them with a high solid content concentration. Make it a cake.
The separated cake is heated and dried to obtain a powdery or granular PVA product.

The method for incorporating the surfactant into the PVA resin is not particularly limited, and examples thereof include a method of mixing the PVA resin (particularly the particulate PVA resin) and the surfactant. The timing of mixing is not particularly limited, and for example, the surfactant may be mixed (further dried) with the separated cake (separated cake before drying), or the PVA resin after drying (for example, after drying and grinding) (particularly). The particulate PVA resin) and the surfactant may be mixed.

The mixing method is not particularly limited, and examples thereof include a method of attaching or applying (coating) a surfactant to the surface (or surface layer) of the PVA resin (particles).

In mixing (or coating), the surfactant may be used as it is, or a mixed solution of the surfactant and the solvent (particularly a solution of the surfactant) may be used.

Examples of the solvent include organic solvents [eg, alcohols (eg, methanol, ethanol, etc.), esters (eg, methyl acetate, ethyl acetate, etc.), dimethyl sulfoxide (DMSO), etc.], water, and the like. These solvents may be used alone or in combination of two or more.

The solvent containing water may contain other solvents (the above-exemplified organic solvents such as methanol, ethanol, methyl acetate, ethyl acetate and DMSO).

In particular, it is preferable to use at least a mixed solvent of water and alcohols (particularly at least alcohols containing methanol) as the solvent. Such a solvent is suitable because it is easy to prepare a high-concentration solution, although it depends on the type of the surfactant.

In addition, the mixed solution may contain other components or additives (for example, sodium acetate, PVA resin, etc.).

In the mixed solution (solution), the concentration of the surfactant is not particularly limited, and may be, for example, 1 to 90% by mass, preferably 3 to 80% by mass, and more preferably 5 to 70% by mass. From the viewpoint of uniform coating while suppressing the granulation of PVA particles, the concentration of the surfactant may be relatively high (for example, 10% by mass or more, 30% by mass or more, 50% by mass or more). ..

The equipment (mixing means) used for mixing the PVA resin and the surfactant is not particularly limited as long as it can mix the surfactant with the PVA resin (particles). For example, as a general blending equipment, there is no particular limitation. , Blenders and mixers for powders such as kneader type mixers, surfactant mixers, and drum blenders can be used. Furthermore, it is not originally a blender such as rotary kilns, various crushers, crushers, screw conveyors, rotary valves, and air pump lines, but is used for equipment and equipment used for particle size adjustment, drying, powder transportation, etc. The equipment may be such that a fixed amount of the activator is continuously added by a pump or the like.

The mixing temperature is not particularly limited, and may be, for example, at room temperature or under heating (high temperature).

Examples of mixing under heating include an example in which a surfactant is mixed (for example, sprayed or dropped) with PVA having a high temperature of about 40 to 120 ° C. in a dryer in the PVA manufacturing process. Be done.

Further, a surfactant may be added and mixed in the PVA manufacturing process. That is, the surfactant may be added so as to be coated on the surface of the PVA resin (particles).

The PVA resin (particles) after mixing may or may not be dried. For example, when the concentration of the surfactant is high and the mixing amount is small, the amount of the solvent (particularly water or methanol) contained in the PVA resin is very small, and it can be used as it is without drying. sell.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

(Example 1)
PVA (manufactured by Nippon Vinegar Bi-Poval Co., Ltd., variety name J-Poval JP-18: volatile content 3.7%, sodium 0.5% by mass, vinyl acetate polymerized and saponified PVA, degree of polymerization 1810, 100 g of particles obtained by pulverizing a saponification degree of 88.05 mol%, 4% aqueous solution viscosity of 28.5 mPa · s) to a particle size of # 14 or less, and a surfactant [manufactured by Sannopco, SN Deformer 444, nonionic surfactant) / water / Place 0.005 g (0.0025 g of pure surfactant) in a 50% by mass solution of surfactant prepared by dissolving methanol (mass ratio = 50/25/25) in a plastic bottle and seal the plastic bottle tightly. PVA particles whose surface was coated with a surfactant were prepared by shaking (adding 0.0025% by mass to PVA as a surfactant).
In addition, the obtained particles kept the particles in a free-flowing state even if they were not dried.

Then, 405 g of hot water at 50 ° C. is put into a 500 cc hard glass beaker, and 45 g of the PVA particles prepared above are charged at once while stirring by rotating a two-bladed propeller stirring blade having a length of 20 mm at 300 rpm. When the dispersion test was performed, the particles were uniformly dispersed in warm water at 50 ° C., and no mamaco or dango-like lumps were generated.

(Reference example 1)
PVA particles were prepared and a dispersion test was conducted in the same manner as in Example 1 except that 0.005 g of water was used instead of 0.005 g of a 50% by mass solution of the surfactant in Example 1. A large mamaco with a diameter of 15 to 30 mm was formed, and even if stirring was continued for a long time, the mamaco could not be completely dissolved and the mamaco remained.

(Reference example 2)
PVA particles in the same manner as in Example 1 except that 0.005 g of water / methanol (mass ratio = 50/50) was used instead of 0.005 g of the surfactant 50% by mass solution in Example 1. Was prepared.
When the same dispersion test as in Example 1 was performed on the obtained PVA particles, a large number of large mamaco having a diameter of 15 to 30 mm were formed, and even if stirring was continued for a long time, the mamaco could not be completely dissolved and the mamaco was found. The remaining.

(Examples 2 to 6)
In Example 1, PVA particles were prepared in the same manner as in Example 1 except that the addition amount of 0.005 g of the surfactant 50% by mass solution was changed and the addition amount of the surfactant was as shown in the table below. It was prepared and subjected to a dispersion test.

The table below shows the amount of surfactant added and the results of the dispersion test.

(Examples 7 to 9 and reference examples 3 to 4)
In Example 1, PVA particles were prepared and subjected to a dispersion test in the same manner except that the surfactant was changed to the additive shown in the table below.

The table below shows the types of additives, the results of the dispersion test, and remarks.

(Examples 10 to 12)
Example 3 (addition amount) except that the surfactant 50% by mass solution [water / methanol = 50/50 (mass ratio) mixed solution] was changed to the surfactant solution shown in the table below in Example 1. PVA particles were prepared and subjected to a dispersion test in the same manner as in 0.0025% by mass vs. PVA).

The table below shows the types of surfactant solutions, the amount added, and the results of the dispersion test.

(Example 13)
PVA for PVC suspension polymerization (manufactured by Nippon Vinegar Bi Poval Co., Ltd., product name J-Poval JL-25E: volatile content 4.1%, sodium 0.2% by mass, vinyl acetate polymerized and saponified PVA , Polymerization degree 2560, sacrifice degree 80.26 mol%, 4% aqueous solution viscosity 46.5 mPa · s) # 20 pulverized particles 1000 g were placed in a small tabletop kneader type mixer and stirred with a surfactant (manufactured by Sannopco). 0.01 g of SN deformer 777, a nonionic surfactant) was added to prepare PVA particles in which the surface of the PVA particles was coated with the surfactant (0.001% by mass vs. PVA added as a pure content).

Then, 405 g of water at 20 ° C. is put into a 500 cc hard glass beaker, and 45 g of the PVA particles prepared above are put in at once while stirring by rotating a two-bladed propeller stirring blade having a length of 20 mm at 300 rpm. When the dispersion test was carried out, the particles were uniformly dispersed in water at 20 ° C., and no mamaco or dango-like lumps were generated.

On the other hand, when the same dispersion test was performed using the original # 20 pulverized particles not coated with the surfactant, the whole was floated on the water surface with a large mass of mamaco, and then stirring was continued for 24 hours or more. However, the lumps remained until the end and could not be completely dissolved.

(Example 14)
Maleic acid-modified PVA (volatile content 4.6%, sodium acetate 2.1% by mass, vinyl acetate / maleic acid ester polymerized and sacrificed PVA, saponification degree 89.14 mol%, 4% aqueous solution viscosity 29.2 mPa · s , Maleic acid denaturation degree 3.8 mol%) # 150 crushed particles 100 g and surfactant (manufactured by Sannopco, SN deformer 1312, silicone defoamer) 0.02 g are put in a plastic bag, sealed and hand-made. PVA particles were prepared by mixing and coating the surface of the particles with an antifoaming agent.

Then, 405 g of hot water at 50 ° C. is put into a 500 cc hard glass beaker, and 45 g of the PVA particles adjusted above are charged at once while stirring by rotating a two-bladed propeller stirring blade having a length of 20 mm at 300 rpm. When the dispersion test was performed, it was uniformly dispersed in warm water at 50 ° C., and a uniform aqueous solution completely dissolved without heating was obtained by stirring for 10 minutes without generating any mamaco or dango-like lumps. Was completed.

On the other hand, when the same dispersion test was performed using # 150 pulverized particles not coated with a surfactant, a large mamaco having a diameter of 10 to 30 mm was formed, and even if heating was continued and stirring was continued, it was completely completed. Could not dissolve in.

(Example 15)
PVA (manufactured by Nippon Vinegar Bi-Poval Co., Ltd., product name J-Poval JP-24S: volatile content 3.5%, sodium 0.5% by mass, vinyl acetate polymerized and saponified PVA, degree of polymerization 2450, 100 g of # 100 pass crushed particles with a saponification degree of 88.15 mol% and a 4% aqueous solution viscosity of 46.2 mPa · s) and 0.06 g of a surfactant (manufactured by Sannopco, SN deformer 485, polyether defoaming agent) in a plastic bag. PVA was prepared by putting it in, sealing it, mixing it by hand, and coating the surface of the particles with a surfactant (0.06% by mass vs. PVA was added as a surfactant).

Then, 405 g of hot water at 60 ° C. is put into a 500 cc hard glass beaker, and 45 g of the PVA particles adjusted above are put in at once while stirring by rotating a two-bladed propeller stirring blade having a length of 20 mm at 300 rpm. When the dispersion test was carried out, the particles were uniformly dispersed in hot water at 60 ° C., and no mamaco or dango-like lumps were generated.

On the other hand, when the same dispersion test was carried out using # 100 pass pulverized particles not coated with a surfactant, the whole became a large mamaco and could not be dissolved at all even if stirring was continued for a long time. ..

(Example 16)
PVA (manufactured by Nippon Vinegar Bi-Poval Co., Ltd., product name J-Poval JC-40: PVA obtained by polymerizing and saponifying with 3.8% volatile content, 0.2% by mass of sodium acetate, and vinyl acetate. , Polymerization degree 4120, saponification degree 99.51 mol%, 4% aqueous solution viscosity 235 mPa · s) # 14 pulverized particles 100 kg were placed in a screw conveyor, and glycerin fatty acid ester / water as a surfactant / water (mass ratio = 25/75). ) 200 g of a 25% by mass aqueous solution was continuously added dropwise and mixed to prepare PVA particles coated with a surfactant (0.05% by mass vs. PVA was added as a pure surfactant).

Then, 80 kg of hot water at 80 ° C. was put into a 100 L dissolution tank, and a dispersion test was conducted in which 20 kg of PVA particles prepared above were charged at once while stirring by rotating a three-bladed propeller stirring blade at 150 rpm. However, it was uniformly dispersed in hot water at 80 ° C., no mamaco or dango-like lumps were generated, and the temperature was further raised to 95 ° C. to obtain a homogeneous aqueous solution.

On the other hand, when the same dispersion test was carried out using # 14 pulverized particles not coated with a surfactant, a large number of dango-like lumps having a diameter of 5 to 10 mm were formed and heated to 95 ° C. 5 Even after stirring for a while, very small undissolved dango particles of 0.5 to 3 mm remain, and even if this aqueous solution is poured and dried, a smooth and homogeneous film can be obtained for the undissolved dango particles. There wasn't.

(Reference example 5)
In Reference Example 1, the dispersion test was carried out in the same manner as in Reference Example 1 except that 0.0005 g of a 50 mass% surfactant solution (0.0025 g of pure surfactant) was added together with 405 g of warm water at 50 ° C. As a result, a large mamaco having a diameter of 15 to 30 mm was formed, and even if stirring was continued for a long time, the mamaco could not be completely dissolved and the mamaco remained.
That is, even if the surfactant was not mixed with the PVA particles and the surfactant was mixed at the time of mixing with water, the solubility or dispersibility could not be improved.

According to the present invention, it is possible to provide a novel PVA resin containing a surfactant. Such a PVA resin has excellent dispersibility or solubility in water and the like, and can be applied to various uses.
In particular, in the present invention, a sufficient effect can be obtained even if the amount of the surfactant added is relatively small. Therefore, in the present invention, it is possible to provide a material having excellent solubility or dispersibility while being substantially equivalent to a PVA resin, which is extremely useful.

Claims (10)

A polyvinyl alcohol resin containing a surfactant, wherein the surfactant contains a nonionic surfactant, the ratio of the surfactant is 0.0001 to 0.1% by mass with respect to the polyvinyl alcohol resin, and 10 meshes are used. Polyvinyl alcohol resin, which is a resin particle that passes through the sieve. The resin according to claim 1, wherein the polyvinyl alcohol resin has a degree of polymerization of 500 or more. The resin according to claim 1 or 2, wherein the polyvinyl alcohol resin has a saponification degree of 97 mol% or less. The resin according to any one of claims 1 to 3, wherein the polyvinyl alcohol resin has a saponification degree of 70 to 95 mol%. The resin according to any one of claims 1 to 4, wherein the polyvinyl alcohol resin has a saponification degree of 70 to 95 mol% and a polymerization degree of 500 to 5000. The resin according to any one of claims 1 to 5, wherein the nonionic surfactant comprises at least one selected from an ether type surfactant, an ester type surfactant, and a polypropylene glycol ether type surfactant. The resin according to any one of claims 1 to 6 , wherein a surfactant is present on at least the surface of the polyvinyl alcohol resin. The method for producing a resin according to any one of claims 1 to 7 , wherein the polyvinyl alcohol resin and the surfactant are mixed. The production method according to claim 8 , wherein the polyvinyl alcohol resin is mixed with a mixed solution of a surfactant and a solvent. The production method according to claim 9 , wherein the solvent is a mixed solvent of water and alcohols.