JP6479381B2 - Method for producing water-resistant composition - Google Patents

Description

  The present invention relates to a water-resistant composition containing a vinyl alcohol polymer and oxide particles, a production method thereof, and an antifogging agent.

  Conventionally, vinyl alcohol polymers (hereinafter, vinyl alcohol polymers may be abbreviated as PVA) are widely used as various binders, adhesives, surface treatment agents, and the like. PVA is known to have excellent performance that does not allow other water-soluble resins to follow in terms of film-forming properties and strength. However, since PVA is water-soluble, it has a drawback that it is low in water resistance, particularly when it is dried at a low temperature. Therefore, various methods for improving this defect have been studied (see Non-Patent Document 1). For example, a method of crosslinking PVA with glyoxal, glutaraldehyde, dialdehyde starch, a water-soluble epoxy compound, a methylol compound or the like is known. However, in order to make the PVA sufficiently water resistant by this method, it is necessary to perform heat treatment for a long time at a high temperature of 100 ° C. or higher, particularly 120 ° C. or higher. It is also known that a strong acid condition of, for example, pH 2 or lower may be used for water resistance by low temperature drying. However, in this case, the viscosity stability of the PVA aqueous solution is poor and gelation may occur during use. Moreover, there exists a problem that PVA color | colors by making it such a severe condition, and the external appearance of the membrane | film | coat obtained is impaired.

  In addition, as a method of using an inorganic crosslinking agent, (1) a method of imparting water resistance by blending titanium lactate into an aqueous composition containing PVA (see JP-A-49-94768), (2) aluminum, A method for imparting water resistance by blending a water-insoluble inorganic substance containing silicon, magnesium or calcium element (see Japanese Patent Publication No. 3-75561) has been studied. However, in the method of (1), when the substrate is coated with the composition and then treated at a relatively low temperature around room temperature, sufficient water resistance cannot be imparted, for example, the obtained film disintegrates in boiling water. Moreover, the low temperature storage stability (aqueous solution viscosity stability) of the PVA aqueous solution blended with titanium lactate is also low. On the other hand, according to the method (2), although high water resistance is expressed, the aqueous solution viscosity stability of the composition is difficult and the transparency of the resulting film is low. Therefore, the applicable range of use is limited.

Latest technological trends and industrial applications of water-soluble and water-dispersible polymer materials, published by Nippon Chemical Information Co., Ltd., 2001, pp. 567-589

JP-A-49-94768 Japanese Patent Publication No. 3-75561

  The present invention has been made on the basis of the circumstances as described above, and is excellent in aqueous solution viscosity stability. Even when dried at a relatively low temperature such as near room temperature, it is not limited to cold water but also to hot water and hot water. Another object of the present invention is to provide a water-resistant composition having excellent water resistance and high transparency. Another object of the present invention is to provide a method for producing such a water-resistant composition and an antifogging agent containing the water-resistant composition.

The invention made to solve the above problems is
A vinyl alcohol polymer (A), and metal oxide particles (B) having a coordination number of 6 or more,
The oxide particles (B) have an average dispersed particle size of 50 nm or less,
The water-resistant composition having a mass ratio (A / B) of the vinyl alcohol polymer (A) to the oxide particles (B) of 30/70 or more and 90/10 or less.

  The reason why the water-resistant composition can exhibit excellent water resistance and the like is not clear, but for example, the following reasons can be considered. The oxide particles (B) contained in the water-resistant composition are formed from a metal oxide having a small particle size and a high coordination number. For this reason, since the metal in the oxide particles (B) has a high surface exposure rate and can be highly coordinated, it can efficiently form a coordinate bond with the hydroxyl group of PVA (A). Therefore, the water-resistant composition can exhibit excellent water resistance even when dried at a relatively low temperature such as around room temperature. Moreover, by using such an oxide particle (B), aqueous solution viscosity stability is also high and it is excellent also in transparency. The “metal coordination number” refers to the coordination number when the metal (atom) serves as a central atom to form a complex.

  The saponification degree of the vinyl alcohol polymer (A) is preferably 85 mol% or more and 99.99 mol% or less. By using PVA (A) having a saponification degree within the above range, water resistance and the like can be further improved.

  The average dispersed particle size of the oxide particles (B) is preferably 20 nm or less. Thus, water resistance, transparency, etc. can be improved more by using the oxide particle (B) with a smaller particle diameter.

The oxide constituting the oxide particles (B) may be zirconium oxide (ZrO ₂ ) and / or titanium oxide (TiO ₂ ). By using these metal oxides, the above performances can be efficiently exhibited.

The method for producing the water-resistant composition of the present invention comprises:
A step of preparing a mixed liquid in which a vinyl alcohol polymer (A) and a metal oxide particle (B) having an average dispersed particle diameter of 50 nm or less and a coordination number of 6 or more are mixed with water as a dispersion medium. And removing water from the mixed solution,
The mass ratio (A / B) of the vinyl alcohol polymer (A) to the oxide particles (B) is from 30/70 to 90/10. According to the method for producing a water-resistant composition, a water-resistant composition excellent in water resistance and transparency can be efficiently obtained.

  Moreover, the antifogging agent of this invention contains the said water-resistant composition. The antifogging agent can form a film having excellent water resistance and transparency, and can exhibit excellent antifogging performance.

  As described above, the water-resistant composition of the present invention can exhibit excellent aqueous solution viscosity stability, water resistance and transparency by including the specific oxide particles (B). Moreover, according to the manufacturing method of the water-resistant composition of this invention, the water-resistant composition excellent in water resistance and transparency can be obtained efficiently. The antifogging agent of the present invention can form a film having excellent water resistance and transparency, and can exhibit excellent antifogging performance.

  Hereinafter, embodiments of the water-resistant composition, the production method thereof and the antifogging agent of the present invention will be described in detail.

(Water resistant composition)
The water-resistant composition of the present invention contains PVA (A) and specific oxide particles (B). Here, the water-resistant composition is a composition that can exhibit water resistance when molded or cured into a film shape, a layer shape, a sheet shape, an indeterminate shape, or other shapes, or has water resistance. A molded or cured composition. That is, the state of the water-resistant composition is not particularly limited, and may be in the form of powder, or in the form of a liquid (solution or slurry) dispersed or dissolved in a dispersion medium such as water. Further, it may be a solid state (molded body such as a film) obtained by drying the liquid state.

(PVA (A))
As PVA (A), a polymer produced by a conventionally known method, that is, a polymer produced by saponifying a vinyl ester polymer generally obtained by polymerizing a vinyl ester monomer can be used. .

  The said vinyl ester polymer will not be specifically limited if it is a polymer obtained by superposing | polymerizing by a conventionally well-known method using 1 type, or 2 or more types of vinyl ester monomers. The vinyl ester polymer may be a copolymer of one type or two or more types of vinyl ester monomers and other monomers copolymerizable therewith, or using only vinyl ester monomers. The obtained polymer may be sufficient.

  Examples of the vinyl ester monomers include vinyl formate, vinyl acetate, vinyl propionate, vinyl valelate, vinyl laurate, vinyl stearate, vinyl benzoate, vinyl pivalate, vinyl versatate, and the like. Of these, vinyl acetate is preferred.

Examples of other monomers copolymerizable with the vinyl ester monomers (hereinafter also referred to as “other monomers”) include, for example, olefins having 2 to 10 carbon atoms such as ethylene, propylene, 1-butene, and isobutene;
Acrylic acid or a salt or ester thereof;
Methacrylic acid or a salt or ester thereof;
Acrylamide derivatives such as acrylamide, N-methyl acrylamide, N-ethyl acrylamide, N, N-dimethyl acrylamide, diacetone acrylamide, acrylamide propane sulfonic acid or its salt, acrylamide propyl dimethylamine or its salt, N-methylol acrylamide or its derivative ;
Methacrylamide derivatives such as methacrylamide, N-methyl methacrylamide, N-ethyl methacrylamide, methacrylamide propane sulfonic acid or salts thereof, methacrylamide propyl dimethylamine or salts thereof, N-methylol methacrylamide or derivatives thereof;
N-vinylamides such as N-vinylformamide, N-vinylacetamide, N-vinylpyrrolidone;
Vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, i-propyl vinyl ether, n-butyl vinyl ether, i-butyl vinyl ether, t-butyl vinyl ether, dodecyl vinyl ether, stearyl vinyl ether;
Vinyl cyanides such as acrylonitrile and methacrylonitrile;
Vinyl halides such as vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride;
Allyl compounds such as allyl acetate and allyl chloride;
Maleic acid, maleate, maleic ester or maleic anhydride;
Itaconic acid, itaconic acid salt, itaconic acid ester or itaconic anhydride;
Vinylsilyl compounds such as vinyltrimethoxysilane;
And isopropenyl acetate.
Among these, in order to further improve the water resistance by stabilizing the crosslinked structure, a copolymerizable monomer having a functional group capable of multidentate coordination with a metal atom is preferably used.
Carboxylic acid-containing monomers such as acrylic acid and its salts, methacrylic acid and its salts, maleic acid and its salts, maleic acid monoester, itaconic acid and its salts, itaconic acid monoester;
Sulfonic acid-containing monomers such as vinyl sulfonic acid and its salt, allyl sulfonic acid and its salt, methallyl sulfonic acid and its salt, isoprene sulfonic acid and its salt, 2-acrylamido-2methylpropane sulfonic acid and its salt;
Preferred are phosphonic acid-containing monomers such as vinylphosphonic acid and salts thereof, and allylphosphonic acid and salts thereof.

  The proportion in the case where the structural unit derived from the other monomer in the vinyl ester polymer is contained is 0.01 mol% or more and 15 mol% or less with respect to all the structural units constituting the vinyl ester polymer. It is preferably 10 mol% or less.

  The saponification method of the said vinyl ester polymer is not specifically limited, A well-known saponification method is employable. Examples include saponification reactions (including alcoholysis reactions) using basic catalysts such as sodium hydroxide, potassium hydroxide, sodium methoxide, and acidic catalysts such as p-toluenesulfonic acid.

Although there is no restriction | limiting in particular as a polymerization degree of PVA (A), From viewpoints, such as water resistance, it is preferable that it is 500 or more, It is more preferable that it is 1,000-5,000, 1,200-3 More preferably, it is 1,000. Here, the polymerization degree means an average polymerization degree measured according to the description of JIS K6726-1994. After re-saponifying and purifying PVA (A), the intrinsic viscosity measured in water at 30 ° C. [η ] (Unit: liter / g).
Degree of polymerization = ([η] × 10 ⁴ /8.29) ^{(1 / 0.62)}

  The lower limit of the degree of saponification of PVA (A) is, for example, 80 mol%, but from the viewpoint of water resistance and the like, 85 mol% is preferable, 90 mol% is more preferable, 95 mol% is still more preferable, and 98 mol% Is even more preferable. On the other hand, the upper limit of the saponification degree is preferably 99.99 mol%, more preferably 99 mol% from the viewpoint of aqueous solution viscosity stability and the like. Here, the degree of saponification of PVA (A) refers to the number of vinyl alcohol units relative to the total number of moles of structural units (typically vinyl ester monomer units) and vinyl alcohol units that can be converted to vinyl alcohol units by saponification. The ratio (mol%) occupied by the number of moles. The degree of saponification of PVA (A) can be measured according to the description of JIS K6726-1994.

  PVA (A) may consist of only one type of PVA, or may be a blend of two or more types of PVA polymers having different degrees of polymerization, saponification, and modification.

(Oxide particles (B))
The oxide particles (B) are metal oxide particles having a coordination number of 6 or more. The oxide particles (B) are insoluble in water. The oxide particles (B) are mainly (substantially) composed of two types of atoms, ie, a metal atom having a coordination number of 6 or more and an oxygen atom, and can exhibit the effects of the present invention. Other atoms may be included in the range.

  As a metal having a coordination number of 6 or more, a metal having a coordination number of 6, such as Ni (II), Cr (III), Fe (III), Co (III), Rh (III), Ti (IV), etc. Examples thereof include metals having a coordination number of 8 such as Mo (IV) and Zr (IV) and metals having a coordination number of 10 or more such as La (III) and Ce (III). This metal is preferably a transition element (Group 3 to Group 11 element) from the viewpoint that multi-coordination is possible, and more preferably Group 4 elements (Ti, Zr, Hf, Rf) of the periodic table. Ti (titanium) and Zr (zirconium) are more preferable. These metals are presumed to be particularly well coordinated with PVA (A), and the water resistance, transparency and the like can be improved more effectively.

  The average dispersed particle size of the oxide particles (B) is 50 nm or less, preferably 20 nm or less. By using the oxide particles (B) having a small particle size, the water resistance and appearance when formed into a film (colorless or transparent) can be improved. On the other hand, the lower limit of the average dispersed particle size of the oxide particles (B) is, for example, 0.5 nm, 1 nm, or 10 nm. The average dispersed particle diameter is an average particle diameter measured in a state where each primary particle is dispersed, and is a value measured by a transmission electron microscope (TEM).

  Commercially available oxide particles (B) can be used as appropriate. Moreover, oxide particle (B) can be used individually by 1 type or in mixture of 2 or more types.

  As mass ratio (A / B) of PVA (A) and oxide particle (B), they are 30/70 or more and 90/10 or less, and 40/60 or more and 80/20 or less are preferable. By making mass ratio (A / B) of PVA (A) and oxide particle (B) into such a range, coexistence with water resistance, intensity | strength, etc. can be aimed at.

  The water-resistant composition can contain other components as needed in addition to PVA (A) and oxide particles (B). Examples of other components include a solvent (dispersion medium), various additives, other water-soluble resins, and a polymer aqueous dispersion. The solvent is generally water, but various alcohols, ketones, dimethylformamide, dimethyl sulfoxide, and other solvents can be used in combination. Examples of additives include surfactants, pH adjusters, or fillers such as calcium carbonate, clay, talc, and wheat flour. Examples of water-soluble resins include cellulose derivatives such as carboxymethylcellulose and hydroxyethylcellulose, (meth) acrylic polymers such as poly (meth) acrylic acid, polyhydroxy (meth) acrylate, and polyacrylamide, polyvinylpyrrolidone, and polyvinylacetamide. It is done. Examples of the polymer aqueous dispersion include acrylic polymers, ethylene-vinyl acetate copolymers, vinyl ester polymers, styrene-butadiene copolymers, and the like.

  The water-resistant composition makes use of properties such as water resistance, and is a coating agent for organic and inorganic materials such as paper and resin, an antifogging agent, a coating layer for a recording material, an adhesive, a binder, a vehicle for paint, a hydrogel. It can be used for a substrate for use. The antifogging agent will be described in detail later.

(Method for producing water-resistant composition)
The method for producing the water-resistant composition of the present invention comprises:
A step of preparing a mixed liquid in which a vinyl alcohol polymer (A) and a metal oxide particle (B) having an average dispersed particle diameter of 50 nm or less and a coordination number of 6 or more are mixed with water as a dispersion medium. (I), and step (II) of removing water from the mixture
Have The mass ratio (A / B) of the vinyl alcohol polymer (A) to the oxide particles (B) is from 30/70 to 90/10. According to the method for producing a water-resistant composition, a water-resistant composition such as a film having excellent water resistance and transparency can be efficiently obtained.

  In the case where the water-resistant composition is sold or distributed in a liquid state, only the step (I) is required only during production, and the step (II) is further performed when used as a coating agent or the like. By passing through process (II), the water resistant composition as a molded object (film shape etc.) excellent in water resistance etc. can be obtained.

  In step (I), for example, PVA (A) and oxide particles (B) may be dissolved or dispersed in water to obtain a mixed solution, or an aqueous solution of PVA (A) and oxide particles ( B) may be mixed with a dispersion dispersed in water to obtain a mixed solution.

  In step (II), for example, the mixture obtained in step (I) is coated on a substrate and dried at a low temperature around room temperature, for example, so that it can be used not only in cold water but also in warm water and boiling water. In contrast, a dry water-resistant composition having sufficient water resistance can be obtained. Note that drying or heat treatment may be performed at a high temperature for drying in a short time or for improving water resistance.

(Anti-fogging agent)
The antifogging agent of this invention contains the said water resistant composition. The said anti-fogging agent can contain another component other than PVA (A) and oxide particle (B) as needed. Examples of the other components include those exemplified as other components that may be contained in the water-resistant composition. The antifogging agent may be in the form of a powder composed of PVA (A) and oxide particles (B), or may be in the form of liquid (slurry) in which PVA (A) is dissolved in water, It may be a solid after application (drying).

  The antifogging agent (waterproof composition) can obtain a film excellent in water resistance and transparency, and the obtained film can exhibit excellent antifogging performance. Therefore, it can be suitably used as a coating agent (antifogging agent) for optical lenses, glasses, vehicle window glass, and the like that require transparency and antifogging properties.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples. In the examples, unless otherwise specified, “%” and “part” mean “% by mass” and “part by mass”, respectively. Each evaluation was performed by the following methods.

(Measurement of average dispersed particle size by transmission electron microscope)
The average dispersed particle size of the oxide particles in the sheet-like materials prepared in Examples and Comparative Examples was measured using a transmission electron microscope (TEM) (JEOL JEM-2100) under the following conditions. The obtained sheet was embedded by photopolymerization using a resin (Aronix). Next, this was trimmed by 5 μm using a microtome. Further, the surface was chamfered by 1 μm, and TEM observation was performed using a transmission electron microscope JEM-2100 (manufactured by JEOL) as a measurement sample obtained by cutting into a 20 nm ultrathin section. The maximum diameter of the oxide particles dispersed in the sheet was measured from the obtained TEM image. Fifty oxide particles were measured, and the average value was defined as the average dispersed particle size.

(Aqueous solution viscosity stability of water-resistant composition)
A 4% aqueous solution of the water-resistant composition prepared in Examples and Comparative Examples was prepared and left in a constant temperature bath at 20 ° C. The viscosity immediately after the temperature of this aqueous solution reached 20 ° C. and the viscosity after standing at 20 ° C. for 7 days were measured. A value obtained by dividing the viscosity immediately after this by 7 days (viscosity after 7 days / viscosity immediately after) was determined as the thickening ratio (times) and determined according to the following criteria. The lower the thickening factor, the better the water-soluble viscosity stability.
○: Less than 2.5 times △: 2.5 times or more and less than 3.5 times ×: 3.5 times or more

(Swelling degree and dissolution rate of sheet (water resistant composition))
Samples obtained by cutting out the sheet-like materials obtained in Examples and Comparative Examples into 5 cm squares were prepared, and the degree of swelling and dissolution rate were calculated as follows.
Swelling degree (times) = b / (a × e / d)
Elution rate (%) = [{(a × e / d) −c} / (a × c / d)] × 100
a: Mass (g) of the sheet before immersion
b: Mass (g) of the sheet-like material pulled up after being immersed in 20 ° C. water for 24 hours
c: Mass (g) after being dipped in water at 20 ° C. for 24 hours and then pulled up and dried at 105 ° C. for 24 hours.
d: Mass of sheet-like material cut out separately (g)
e: Mass after the sheet-like material cut out at d is dried at 105 ° C. for 24 hours.

(Water resistance of sheet-like material against hot water)
The sheet was immersed in hot water in a boiling water bath for 1 hour. It pulled up after immersion and observed the swelling state of the sheet-like material visually. The swelling state and the state that could not be pulled up were evaluated in the following points.
◎: Swelling and shape retention ○: Swelling is large but shape retention △: Cannot be pulled up (collapse)
×: Completely collapsed

(Anti-fogging property of test piece)
The test piece which provided the coating film on the glass plate produced by the Example and the comparative example was used. The mouth of a 200 ml beaker containing 100 ml of 40 ° C. warm water was covered with the side of the test piece provided with the coating film, and left in a 40 ° C. atmosphere for 24 hours. After standing, the adhesion of water droplets on the coat surface was visually observed.
○: Water uniformly adheres to the surface of the coat surface, and no cloudiness is observed.
Δ: Partial or slight cloudiness was observed.
X: Water droplets adhered, and significant clouding was observed.

<Synthesis of PVA-1>
A 6L reactor equipped with a stirrer, nitrogen inlet, additive inlet and initiator inlet was charged with 2250 g of vinyl acetate and 750 g of methanol, heated to 60 ° C. and then purged with nitrogen by nitrogen bubbling for 30 minutes. did. The temperature in the reaction vessel was adjusted to 60 ° C., and 0.9 g of 2,2′-azobis (isobutyronitrile) was added to initiate polymerization. The polymerization temperature was maintained at 60 ° C. during the polymerization. After 4 hours, when the polymerization rate reached 50%, the polymerization was stopped by cooling. Next, unreacted vinyl acetate was removed under reduced pressure to obtain a methanol solution of polyvinyl acetate (hereinafter sometimes abbreviated as PVAc). The concentration of the PVAc methanol solution was adjusted to 25%, and the NaOH methanol solution (10% concentration) was adjusted so that the alkali molar ratio (number of moles of NaOH / number of moles of vinyl ester units in PVAc) was 0.007. Added and saponified at a temperature of 40 ° C. The obtained vinyl alcohol copolymer was washed with methanol. The saponification degree of PVA-1 obtained by the above operation was 84.0 mol%. It was 1650 when the average degree of polymerization of PVA was measured according to JIS K6726 (1994) of a conventional method.

<Synthesis of PVA-2 to 6>
PVA 2 to 6 were synthesized in the same manner as PVA-1, except that the saponification conditions were changed to the saponification conditions shown in Table 1.

<Synthesis of PVA-7>
A 100 L pressure reactor equipped with a stirrer, nitrogen inlet, ethylene inlet and initiator addition port was charged with 59.2 kg of vinyl acetate and 6.2 kg of methanol, heated to 60 ° C., and then nitrogen bubbling for 30 minutes. The inside was replaced with nitrogen. Next, ethylene was introduced and charged so that the reactor pressure was 0.6 MPa. A 2.8 g / L solution having 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile) dissolved in methanol as an initiator was prepared, and nitrogen substitution was performed by bubbling with nitrogen gas. After adjusting the temperature inside the reaction vessel to 60 ° C., 66 mL of the initiator solution was injected to initiate polymerization. During the polymerization, ethylene was introduced to maintain the reactor pressure at 0.6 MPa, the polymerization temperature at 60 ° C., and the above initiator solution was continuously added at 200 mL / hr. After 4 hours, when the polymerization rate reached 40%, the polymerization was stopped by cooling. The reaction vessel was opened and deethylene removed, and then nitrogen gas was bubbled to completely remove ethylene. Subsequently, the unreacted vinyl acetate monomer was removed under reduced pressure to obtain a PVAc methanol solution. The ethylene modification amount determined from ¹ H-NMR measurement of this PVAc was 4.5 mol%. The methanol solution of PVAc was adjusted to 20%, and the NaOH methanol solution (10% concentration) was adjusted so that the alkali molar ratio (number of moles of NaOH / number of moles of vinyl ester units in PVAc) was 0.05. Added and saponified at a temperature of 40 ° C. The degree of saponification of the obtained modified PVA (PVA-7) was 98.4 mol%. It was 1550 when the average degree of polymerization of PVA-7 was measured according to JIS K6726 (1994) of the conventional method.

<Synthesis of PVA-8>
A 6 L reaction vessel equipped with a stirrer, a nitrogen inlet, an additive inlet and an initiator inlet was charged with 2250 g of vinyl acetate, 750 g of methanol and 0.15 g of itaconic acid, and the inside of the system was maintained for 30 minutes while bubbling nitrogen. Replaced with nitrogen. Further, a comonomer solution having a concentration of 1% by dissolving itaconic acid in methanol was prepared as a delay solution, and nitrogen substitution was performed by bubbling nitrogen gas. The temperature in the reaction vessel was adjusted to 60 ° C., and 0.5 g of 2,2′-azobisisobutyronitrile was added to initiate polymerization. During the polymerization, the temperature in the reaction vessel was maintained at 60 ° C., and the delay solution was added dropwise so that the monomer composition (ratio of vinyl acetate and itaconic acid) in the polymerization solution was constant. After 2.5 hours, when the polymerization rate reached 40%, the polymerization was stopped by cooling. The total amount of the comonomer solution (sequentially added solution) added until the polymerization was stopped was 97 g. Next, unreacted vinyl acetate was removed under reduced pressure to obtain a methanol solution of itaconic acid-modified PVAc. The amount of itaconic acid modification determined from ¹ H-NMR measurement of this PVAc was 0.1 mol%. Adjust the concentration of the PVAc methanol solution to 25% and add NaOH methanol solution (10% concentration) so that the alkali molar ratio is 0.02 (number of moles of NaOH / number of moles of vinyl ester units in PVAc). And saponified at a temperature of 40 ° C. The degree of saponification of the obtained modified PVA (PVA-8) was 98.6 mol%. It was 1870 when the average degree of polymerization of PVA-8 was measured according to JIS K6726 (1994) of the conventional method.
The degree of polymerization, the degree of saponification, and the amount of modification of each PVA obtained are listed again in Table 1.

[Example 1]
PVA-1 (polymerization degree 1650, saponification degree 84 mol%) was dissolved in water to prepare a 4% aqueous solution. To 100 parts of this PVA aqueous solution (4 parts of PVA), 13 parts of a 30% dispersion of zirconium oxide particles (SZR-W, Sakai Chemical Co., Ltd., average particle diameter 5 nm, coordination number 8) (of which zirconium oxide particles 4 Part) was added to prepare a water-resistant composition (4% aqueous solution). This solution was cast and dried at 20 ° C. to obtain a colorless and transparent sheet (sheet-like water-resistant composition: thickness 50 μm). The appearance of the obtained sheet was colorless and transparent. As a result of TEM observation in the sheet-like material, the average dispersed particle size of the oxide particles was 5 nm. Subsequently, when the obtained sheet-like material was immersed in water (20 ° C.) for 24 hours, the degree of swelling and the elution rate were measured. The degree of swelling was 7.9 times, and the elution rate was 21.6%. Furthermore, when it was pulled up after being immersed in hot water in a boiling water bath for 1 hour, the sheet-like material was swollen but maintained a firm shape, and there was no slickness on the surface. Further, even after the aqueous solution of the composition prepared above was allowed to stand at 20 ° C. for 1 week, the aqueous solution maintained fluidity, and its viscosity increase factor was 1.9 times. Further, a separately prepared 10% aqueous solution of the composition was applied on a glass plate so that the thickness of the coating film after drying was 2 μm, and dried at 20 ° C. to prepare a test piece for antifogging evaluation. did. When the above-described evaluation of the antifogging property was carried out using this test piece, no fogging occurred on the test piece.

[Examples 2 to 6]
Except that the PVA type (component (A)) and metal oxide fine particles (component (B)) used in Example 1 were changed as shown in Table 2, the same procedure was performed as in Example 1. . The results are shown in Table 2.

[Comparative Example 1]
PVA-4 (polymerization degree 1650, saponification degree 99 mol%) was dissolved in water to prepare a 4% aqueous solution. In 100 parts of this PVA aqueous solution (4 parts in PVA), zirconia ammonium carbonate ((NH ₄ ) ₂ ZrO (CO ₃ ) ₂ ) aqueous solution (Zircozol AC-7 manufactured by Daiichi Elemental Chemical Co., Ltd., zirconium oxide content 13%) Of 3.4 parts (of which 0.44 parts of zirconium oxide) was added to prepare a water resistant composition (4% aqueous solution). This solution was cast and dried at 20 ° C. to obtain a colorless and transparent sheet (thickness 50 μm). The appearance of the obtained sheet was colorless and transparent. As a result of TEM observation in the sheet-like material, oxide particles were not observed. Subsequently, when the obtained sheet-like material was immersed in water (20 ° C.) for 24 hours, the degree of swelling and the elution rate were measured. The degree of swelling was 6.0 times and the elution rate was 51.3%. However, the sheet was completely dissolved when immersed in hot water in a boiling hot water bath for 1 hour. Moreover, when the aqueous solution of the composition prepared above was left at 20 ° C. for 1 week, the solution gelled within 1 week. Furthermore, a 10% aqueous solution of this composition prepared separately was applied on a glass plate so that the thickness of the coating film after drying was 2 μm, and dried at 20 ° C. to prepare a test piece for antifogging evaluation. did. When the above-described evaluation of the antifogging property was carried out using this test piece, some fogging was observed on the surface of the test piece.

[Comparative Examples 2 to 5]
Except that the PVA type (component (A)) and the metal oxide particles (component (B)) used in Example 1 were changed as shown in Table 2, the same as in Example 1. went. The results are shown in Table 2.

  As shown in Table 2, the water-resistant composition of each example can be applied not only to cold water but also to hot water after film formation or after coating on a substrate and drying at a relatively low temperature such as around room temperature. Water resistance was good. Moreover, it turned out that it is excellent also in viscosity stability, transparency, and anti-fogging property.

  In Comparative Examples 1 and 2, ammonium zirconium carbonate (water-soluble zirconium oxide) was used as the component (B). In Comparative Example 1, the obtained sheet-like material was colorless and transparent, the degree of swelling after being immersed in water (20 ° C.) for 24 hours was 6.0 times, and the elution rate was 51.3%. Moreover, when immersed in hot water in a boiling hot water bath for 1 hour, the sheet was completely dissolved. When the prepared aqueous solution of the composition was allowed to stand at 20 ° C. for 1 week, the solution gelled within 1 week and lacked viscosity stability. In Comparative Example 2, gelation occurred during preparation of the aqueous solution of the composition. Therefore, evaluation as a water resistant composition is not carried out.

In Comparative Examples 3 and 4, the component ratio (A / B) is outside the range of the present invention (A / B = 99/1 or 10/90). In Comparative Example 3, since the ratio of the oxide particles (B) was low, the obtained sheet-like material was colorless and transparent, but collapsed by being immersed in water (20 ° C.). Moreover, the evaluation of antifogging property was inferior.
On the other hand, in Comparative Example 4, since the ratio of the oxide particles (B) was high, the obtained sheet-like material did not have flexibility and strength, and it was impossible to perform water resistance evaluation as a sheet-like material. .

  In Comparative Example 5, the average particle diameter (average dispersed particle diameter) of the oxide particles exceeds 50 nm and is 70 nm. The obtained sheet-like material was white and lacked transparency, and collapsed by being immersed in water (20 ° C.). Moreover, the evaluation of antifogging property was inferior.

In Comparative Examples 6 and 7, the metal coordination number of the oxide particles (B) is less than 6. In Comparative Example 6, the obtained sheet was colorless and transparent, 13.2 times after being immersed in water (20 ° C.) for 24 hours, and the elution rate was 55.3%. Moreover, when immersed in hot water in a boiling hot water bath for 1 hour, the sheet was completely dissolved. Further, even after the composition (aqueous solution) was allowed to stand at 20 ° C. for one week, the aqueous solution maintained fluidity, and the viscosity increasing ratio was 1.2 times.
In Comparative Example 7, the obtained sheet-like material was light blue and transparent, the swelling degree after being immersed in water (20 ° C.) for 24 hours was 10.8 times, and the elution rate was 40.2%. Moreover, when immersed in hot water in a boiling hot water bath for 1 hour, the sheet was completely dissolved. Even after the composition (aqueous solution) was allowed to stand at room temperature (around 20 ° C.) for one week, the aqueous solution maintained fluidity and the thickening factor was 1.7 times.

As described above, the water-resistant composition of the present invention is excellent in aqueous solution viscosity stability, water resistance and transparency, and can be suitably used for anti-fogging agents, other coating agents, adhesives, binders and the like. .

Claims (1)

A mixture of a vinyl alcohol polymer (A) and a metal oxide particle (B) having an average dispersed particle diameter of 50 nm or less and a coordination number of 6 or more with water as a dispersion medium (zirconyl chelate And a step of removing water from the mixed solution,
The mass ratio (A / B) of the vinyl alcohol polymer (A) to the oxide particles (B) is 30/70 or more and 90/10 or less,
The vinyl alcohol polymer (A) having a saponification degree of 99 mol% or less than 88 mol%, average polymerization degree Ri der 1,000 to 5,000,
The manufacturing method of the water-resistant composition whose oxide which comprises the said oxide particle (B) is a zirconium oxide .