JP2003105028A - Vinyl alcohol based polymer and its production method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vinyl alcohol based polymer which can be obtained by an industrially advantageous process, has excellent integrity to a silica compound, and is useful in the application capable of improving performance by this improvement of the integrity, and a process for producing the same. SOLUTION: The silanol-containing vinyl alcohol based polymer can be obtained by reacting a fatty acid vinyl ester copolymer having a diacetoneacrylamide unit with a silane coupling agent having an amino group and saponifying the resulting polymer or reacting a saponified product of a diacetoneacrylamide-fatty acid vinyl ester copolymer with a silane coupling agent having an amino group, and its production process is also disclosed.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a vinyl alcohol polymer having a high binding property with a silica compound and a method for producing the same.

[0002]

BACKGROUND OF THE INVENTION Polyvinyl alcohol (hereinafter abbreviated as PVA) type resins have high film forming properties, excellent adhesive properties, and excellent gas barrier properties, and are therefore widely used in films, coating films, binders and the like. It is used. For example, a laminated film obtained by forming a coating film of a PVA-based resin on a thermoplastic film having a silica vapor deposition layer has high gas barrier properties, and has the advantage that no toxic gas is generated when it is incinerated, In recent years, as interest in the environment has increased, attention has been paid to it. However, the adhesion between the vapor-deposited silica layer and the PVA coated film is not high, and there is a problem that the vapor-deposited silica layer and the PVA coated film peel off when used under high humidity. Further, a particulate silica is used as an ink absorbent in a substrate for an ink jet printer, and a PVA-based resin is used as a binder thereof, but there is a problem that the obtained substrate has insufficient surface strength. .
It is considered that the problems in any of the uses are due to insufficient binding force between the PVA-based resin and the silica compound, and can be solved by introducing a silanol group into PVA.

PVA having such silanol groups introduced
Regarding the resin, in JP-A-58-59203 and JP-A-58-164604, a vinyl-based monomer having an alkoxysilyl group and vinyl acetate are copolymerized,
A production method for saponification is disclosed, and the silanol group-containing PVA-based resin obtained by this method has a high binding property with a silica compound, and in a use using the silica compound and the PVA-based resin, an effect of improving performance is obtained. It has been seen.

However, when a monomer having an alkoxysilyl group and a fatty acid vinyl ester such as vinyl acetate are copolymerized, a large amount of an unreacted monomer having an alkoxysilyl group remains after the polymerization, and the removal thereof is difficult. Difficult,
There is a problem that additional equipment must be newly installed in the existing production equipment to remove it. Further, there is a problem that the monomer having an alkoxysilyl group is expensive and the cost of the obtained silanol group-containing PVA resin is high. Therefore, a silanol group-containing PVA-based resin obtained by an industrially advantageous method has been demanded.

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned drawbacks of the prior art, is obtained by an industrially advantageous method, and has an excellent binding property with a silica compound. , Whose performance can be improved by improving this binding property, for example, a vinyl alcohol polymer useful for applications such as a coating agent for a thermoplastic film having a silica vapor deposition layer, a binder for an ink jet printer substrate, and the like. It is intended to provide a manufacturing method thereof.

[0006]

Means for Solving the Problems The present invention achieves the above object, and in a copolymer having a vinyl alcohol structural unit as a main component, the structural unit represented by the following chemical formula 2 is 0.1 It is a vinyl alcohol polymer characterized by containing ˜15 mol%, and a method for producing the same.

[0007]

[Chemical 2] (An integer of x = 0 to 3, y = 0 to 1, z = 1 to 5, R ₁ ..
R ₂ represents a hydrogen atom, a methyl group or an ethyl group, and R ₃ represents a hydrogen atom, a hydroxyl group, a methyl group, an ethyl group, a methoxy group or an ethoxy group. )

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.

The vinyl alcohol polymer of the present invention is mainly composed of a vinyl alcohol structural unit and contains 0.1 to 15 mol% of a structural unit represented by the following chemical formula 3. Can include unsaponified vinyl ester units, diacetone acrylamide units, and the like.

[0010]

[Chemical 3] (An integer of x = 0 to 3, y = 0 to 1, z = 1 to 5, R ₁ ..
R ₂ represents a hydrogen atom, a methyl group or an ethyl group, and R ₃ represents a hydrogen atom, a hydroxyl group, a methyl group, an ethyl group, a methoxy group or an ethoxy group. )

The vinyl alcohol-based polymer of the present invention is prepared by first preparing a diacetone acrylamide-fatty acid vinyl ester copolymer and then, in the presence of a methanol solvent, a silane coupling agent having an amino group in the copolymer. Or saponification of diacetone acrylamide-fatty acid vinyl ester copolymer, followed by reaction with a silane coupling agent having an amino group in the presence of a methanol solvent. In any case, the vinyl alcohol polymer of the present invention can be obtained by reacting the amino group of the silane coupling agent with the diacetone acrylamide unit.

Examples of the fatty acid vinyl ester used for the production of the above-mentioned diacetone acrylamide-fatty acid vinyl ester copolymer include vinyl formate, vinyl acetate, vinyl propionate, vinyl versatate, etc. Among them, vinyl acetate is industrially used. Most preferred.

As the copolymerization method of diacetone acrylamide and fatty acid vinyl ester, various polymerization methods such as bulk polymerization, solution polymerization, emulsion polymerization, suspension polymerization and the like which are conventionally known in the production method of vinyl ester-based polymers can be used. It can be used, and among them, solution polymerization using methanol as a solvent is industrially preferable.

The diacetone acrylamide-fatty acid vinyl ester copolymer used in the present invention can be copolymerized with diacetone acrylamide or a fatty acid vinyl ester, for example, crotonic acid, acrylic acid, etc., within a range that does not impair the effects of the present invention. Unsaturated monocarboxylic acids such as methacrylic acid and their esters, salts, anhydrides, amides, nitriles, unsaturated dicarboxylic acids such as maleic acid, itaconic acid, fumaric acid and their salts, monomethyl maleate, monomethyl itaconate, etc. Unsaturated dibasic acid monoalkyl esters, C2-C30 α-olefins, alkyl vinyl ethers, vinylpyrrolidones, 3- (meth) acrylamidopropyltrimethoxysilane, 3-
(Meth) acrylamidopropyltriethoxysilane,
3- (meth) acrylamidopropyltri (β-methoxyethoxy) silane, 3- (meth) acrylamidopropyl (N-methylaminoethoxysilane), 2- (meth) acrylamidoethyltrimethoxysilane, 1-
(Meth) acrylamidomethyltrimethoxysilane, 2
-(Meth) acrylamido-2-methylpropyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane and the like copolymerized with a monomer having an alkoxysilyl group, Is also good.

The content of diacetone acrylamide unit in the diacetone acrylamide-fatty acid vinyl ester copolymer is 0.1 to 15 mol%, preferably 1 to 10 mol%. When the amount of diacetone acrylamide unit is less than 0.1 mol%, the amount of the silane coupling agent having an amino group to be added becomes small, and the vinyl alcohol polymer finally obtained has a low binding property to a silica compound. On the other hand, if the amount exceeds 15 mol%, the binding property to the silica compound does not change, which is disadvantageous in that the manufacturing cost increases.

As a method of reacting the diacetone acrylamide-fatty acid vinyl ester copolymer with a silane coupling agent having an amino group before saponification, a silane coupling agent having an amino group in a methanol solution of the copolymer is used. And a method of stirring and mixing at room temperature or high temperature.

Examples of the silane coupling agent having an amino group used herein include, for example, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane,
N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-
Aminopropylmethyldiethoxysilane and the like,
These can be used alone or in combination of two or more.

The addition amount of the silane coupling agent having an amino group is an amount corresponding to 0.1 to 15 mol% with respect to the diacetone acrylamide-fatty acid vinyl ester copolymer, preferably 1 to It is an amount corresponding to 10 mol%. When the addition amount of the silane coupling agent having an amino group is small and less than 0.1 mol% with respect to the copolymer, the binding property of the vinyl alcohol polymer finally obtained to the silica compound is low, On the other hand, 15
Even if the amount exceeds more than mol%, the binding property to the silica compound does not change, which is disadvantageous in that the manufacturing cost increases. Further, the addition amount of the silane coupling agent having an amino group is more than the content of the diacetone acrylamide unit in the above-mentioned copolymer, the binding property to the silica compound is not improved, and the manufacturing cost is increased. It is disadvantageous in that respect.

The method of saponifying a polymer obtained by reacting a diacetone acrylamide-fatty acid vinyl ester copolymer with a silane coupling agent having an amino group is carried out by conventional saponification of a fatty acid vinyl ester copolymer. Further, an acid saponification method can be applied, and among them, a method of adding an alkali hydroxide to a methanol solution of a polymer or a mixed solution of methanol and water, methyl acetate, benzene and the like to effect alcoholysis is industrially preferable.

On the other hand, as a method of reacting a saponified product of diacetone acrylamide-fatty acid vinyl ester copolymer with a silane coupling agent having an amino group,
Without adding a silane coupling agent having an amino group to the diacetone acrylamide-fatty acid vinyl ester copolymer, saponification by the above-mentioned saponification method of the fatty acid vinyl ester polymer, crushed, and then immersed in a methanol solvent A method of adding a silane coupling agent having an amino group and stirring at room temperature or high temperature can be used.

At this time, the above-mentioned silane coupling agent having an amino group can be used, and the addition amount is 0.1 to the saponified product of diacetone acrylamide-fatty acid vinyl ester copolymer, as described above. An amount corresponding to 15 mol%.

The degree of polymerization and the degree of saponification of the vinyl alcohol polymer obtained by reacting the silane coupling agent having an amino group before and after the saponification are not particularly limited, but the degree of saponification is 80 mol% or more, The degree of polymerization is preferably 50 to 4000.

Even when a silane coupling agent having an amino group is reacted before and after saponification, methanol must be present in the reaction system, and the reaction is extremely slow in a solvent other than methanol. It is not possible to easily obtain a vinyl alcohol polymer.
During the reaction, a solvent other than methanol, for example, water, ethanol, ether, benzene or the like may coexist, but the higher the ratio of methanol in the solvent, the higher the rate of the reaction, which is preferable.

The vinyl alcohol polymer of the present invention is water-soluble and is prepared as an aqueous solution before use. The preparation method is not particularly limited, when preparing an aqueous solution of the vinyl alcohol polymer of the present invention, if necessary, starch, methyl cellulose, a cellulose derivative such as carboxymethyl cellulose, a polyacrylic acid derivative,
Other natural polymer such as gelatin, synthetic polymer, clay, kaolin, talc, silica, inorganic filler such as calcium carbonate, plasticizer such as glycerin and sorbitol, surfactant, defoaming agent, antistatic agent, chelate Agents, cross-linking agents and the like can be added within a range that does not impair the effects of the present invention.

[0025]

EXAMPLES Next, the present invention will be described in detail with reference to examples. The vinyl alcohol-based polymers obtained in Examples or Comparative Examples were evaluated by the following methods.

.. Evaluation of Adhesion to Silica Vapor Deposition Film A 5% by mass aqueous solution of the obtained vinyl alcohol polymer was prepared and cast onto a vapor deposition surface of a polyethylene terephthalate film (thickness 12 μm) which was subjected to silica vapor deposition treatment,
Dry at 0 ℃ and 65% RH for 24 hours,
A coating film having a thickness of m was formed. A silica vapor deposition film having a coating film of the above vinyl alcohol polymer is 100 mm
It was cut into a size of 20 mm, and the peel strength between the coating film having a width of 20 mm and the silica vapor deposition film was measured with a Toyo Seiki strograph.

.. Evaluation of Binder Strength for Particulate Silica A 5% by mass aqueous solution of the obtained vinyl alcohol-based polymer was prepared, and 20 parts by mass of particulate silica and 50 parts by mass of pure water were added to 100 parts by mass of the aqueous solution, followed by homomixer (stirring). (Speed: 10000 rpm), and stirred at room temperature for 5 minutes to prepare a coating liquid. The above coating liquid was applied to a copy paper (Ricoh, My Recycle Paper New) No. Four
Approximately 10 g / m ² (solid content) using a 0 bar coater
And apply it to a drum dryer at 105 ° C.
And dried for 120 seconds. A Nichiban cellophane adhesive tape (width: 18 mm) was attached to the obtained coated paper, the peel strength was measured with a Toyo Seiki strograph, and the binder strength of the coating layer was evaluated.

.. Comprehensive Evaluation The respective evaluation results of the adhesion to the silica vapor deposition film and the binder force to the particulate silica were comprehensively evaluated, and the binding property to the silica compound was evaluated according to the following criteria. ⊚: The binding property to the silica compound is very excellent. ◯: Excellent binding property with respect to silica compound and at a practical level. X: The binding property to the silica compound has not reached a practical level.

Synthesis Example of Diacetone Acrylamide-Vinyl Acetate Copolymer Synthesis Example 1 672 parts by mass of vinyl acetate, 10 parts by mass of diacetone acrylamide, and a flask equipped with a stirrer, a thermometer, a dropping funnel and a reflux condenser. Methanol 178
After mass parts were charged and the system was replaced with nitrogen, the internal temperature was adjusted to 6
The temperature was raised to 0 ° C. A solution of 1 part by weight of 2,2'-azobisisobutyronitrile in 50 parts by weight of methanol was added to this system to initiate polymerization. After initiation of the polymerization, a solution prepared by dissolving 55 parts by mass of diacetone acrylamide in 35 parts by mass of methanol was added dropwise at a constant rate over 5 hours.
After 6 hours, the mixture was cooled and the polymerization was stopped. Polymerization yield is 78%
Met. The residual vinyl acetate was distilled off while adding methanol vapor to the obtained reaction mixture to obtain a vinyl acetate-based polymer containing a diacetone acrylamide copolymer component.
A 0 mass% methanol solution was obtained. As shown in Table 1, the content of diacetone acrylamide units in this resin is
It was 5.0 mol% by elemental analysis, and the degree of polymerization was 16
It was 80.

Synthetic Examples 2-3, Comparative Synthetic Examples 1-2 According to the above-mentioned method, vinyl acetate and diacetone acrylamide are copolymerized, and three kinds of vinyl acetate having different contents of diacetone acrylamide unit and degree of polymerization are copolymerized. One type of unmodified polyvinyl acetate was obtained which did not use a polymer and diacetone acrylamide. Table 1 shows data on the degree of modification and the degree of polymerization of these resins.

[0031]

[Table 1]

Example 1 Vinyl acetate polymer obtained in Synthesis Example 1 (degree of polymerization: 16
80, modification degree: 5.0 mol%) to 50 parts of 50% methanol solution, 5.0 parts by mass of γ-aminopropyltrimethoxysilane (5.0 mol% based on vinyl acetate polymer) was added. After mixing and stirring at room temperature, 1 part by mass of a 4 mass% methanol solution of sodium hydroxide was added and mixed well, and a saponification reaction was carried out at 40 ° C. The obtained gel-like material was pulverized, washed well with methanol and then dried to obtain a vinyl alcohol polymer having a saponification degree of 98.5 mol%.

Using the aqueous solution of the obtained vinyl alcohol polymer, the adhesion to a silica vapor deposition film and the Hinder force for particulate silica were evaluated. As shown in Table 2, the adhesiveness and the Hinder force were high, and the binding property to the silica compound was high.

Example 2 The vinyl acetate polymer obtained in Synthesis Example 1 (degree of polymerization: 16)
80, modification degree: 5.0 mol%) in 100 parts by mass of a 50% by mass methanol solution, 3.7 parts by mass of N-β (aminoethyl) γ-aminopropyltrimethoxysilane (3 with respect to the vinyl acetate polymer). 0.0 mol%) was added and mixed and stirred at room temperature, and then a 4% solution of sodium hydroxide in methanol 1
The mass part was added and mixed well, and the saponification reaction was performed at 40 ° C. The obtained gel-like material was pulverized, washed well with methanol and then dried to obtain a vinyl alcohol polymer having a saponification degree of 98.4 mol%.

Using the obtained aqueous solution of the vinyl alcohol polymer, the adhesion to the silica vapor deposition film and the binder force to the particulate silica were evaluated. As shown in Table 2, the adhesiveness and the binder strength were high, and the silica compound showed a high binding property.

Example 3 The vinyl acetate polymer obtained in Synthesis Example 2 (degree of polymerization: 14
90, modification degree: 10.5 mol%) in 100 parts by mass of a 50% by mass methanol solution, 10.9 parts by mass of N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane (10 to vinyl acetate polymer). 0.0 mol%),
After mixing and stirring at room temperature, 1.5 parts by mass of a 4 mass% methanol solution of sodium hydroxide was added and mixed well, and the mixture was mixed at 40 ° C.
The saponification reaction was carried out. The obtained gel-like product was crushed, washed well with methanol and then dried to give a saponification degree of 98.
A 4 mol% vinyl alcohol polymer was obtained.

Using the aqueous solution of the obtained vinyl alcohol polymer, the adhesion to a silica vapor deposition film and the binder force for particulate silica were evaluated. As shown in Table 2, the adhesiveness and the Hinder force were high, and the binding property to the silica compound was high.

Example 4 Vinyl acetate polymer obtained in Synthesis Example 2 (degree of polymerization: 14
90, modification degree: 10.5 mol%) in 100 parts by mass of 50% by mass methanol solution, 5.6 parts by mass of N-β (aminoethyl) γ-aminopropyltriethoxysilane (4 with respect to vinyl acetate polymer 0.0 mol%), and mixed and stirred at room temperature, 1.0 part by mass of a 4 mass% methanol solution of sodium hydroxide was added and mixed well, and a saponification reaction was carried out at 40 ° C. The obtained gel-like product was crushed, washed well with methanol and then dried to give a saponification degree of 88.4 mol%.
To obtain a vinyl alcohol polymer.

Using the obtained aqueous solution of the vinyl alcohol polymer, the adhesion to the silica vapor deposition film and the binder force to the particulate silica were evaluated. As shown in Table 2, the adhesiveness and the binder strength were high, and the silica compound showed a high binding property.

Example 5 The vinyl acetate polymer obtained in Synthesis Example 3 (degree of polymerization: 65)
0, modification degree: 1.2 mol%) to 100 parts by mass of a 50% by mass methanol solution, 1.0 part by mass of γ-aminopropyltrimethoxysilane (1.0 mol% based on vinyl acetate polymer) was added. Then, after mixing and stirring at room temperature, 1.0 part by mass of a 4 mass% methanol solution of sodium hydroxide was added and mixed well, and a saponification reaction was carried out at 40 ° C. The obtained gel-like material was pulverized, washed well with methanol and then dried to obtain a vinyl alcohol polymer having a saponification degree of 98.5 mol%.

Using the aqueous solution of the obtained vinyl alcohol polymer, the adhesion to the silica vapor deposition film and the binder force to the particulate silica were evaluated. As shown in Table 2, the adhesiveness and the binder strength were high, and the silica compound showed a high binding property.

Example 6 The vinyl acetate polymer obtained in Synthesis Example 1 (degree of polymerization: 16)
A 4% methanol solution of sodium hydroxide was added to 100 parts by mass of a 50% by mass methanol solution (80, modification degree: 5.0 mol%) and mixed well, and a saponification reaction was carried out at 40 ° C. The obtained gel-like substance was pulverized, washed well with methanol and then dried to obtain a saponified product of diacetone acrylamide-vinyl acetate copolymer having a saponification degree of 98.5 mol%.

50 parts of the above-mentioned diacetone acrylamide-vinyl acetate copolymer saponified product was added to 200 parts by weight of methanol.
A mass part was added and it was made to immerse. Further, 8.8 parts by mass of γ-aminopropyltrimethoxysilane (5.0 mol% based on the vinyl acetate polymer) was added, and methanol was evaporated in a dryer at 60 ° C. to give a vinyl alcohol polymer. Obtained.

Using the obtained aqueous solution of the vinyl alcohol polymer, the adhesion to the silica vapor deposition film and the binder force to the particulate silica were evaluated. As shown in Table 2, the adhesiveness and the binder strength were high, and the silica compound showed a high binding property.

Example 7 Vinyl acetate polymer obtained in Synthesis Example 1 (degree of polymerization: 16
A 4% methanol solution of sodium hydroxide was added to 100 parts by mass of a 50% by mass methanol solution (80, modification degree: 5.0 mol%) and mixed well, and a saponification reaction was carried out at 40 ° C. The obtained gel-like material was pulverized, washed well with methanol and then dried to obtain a saponified product of diacetone acrylamide-vinyl acetate copolymer having a saponification degree of 88.0 mol%.

50 parts of the above-mentioned diacetone acrylamide-vinyl acetate copolymer saponified product was added to 200 parts by weight of methanol.
A mass part was added and it was made to immerse. Further, 4.0 parts by mass of γ-aminopropyltriethoxysilane (2.0 mol% with respect to the vinyl acetate polymer) was added, and methanol was evaporated in a dryer at 60 ° C. to obtain a vinyl alcohol polymer. Obtained.

Using the aqueous solution of the obtained vinyl alcohol polymer, the adhesion to the silica vapor deposition film and the binder force to the particulate silica were evaluated. As shown in Table 2, the adhesiveness and the binder strength were high, and the silica compound showed a high binding property.

Example 8 Vinyl acetate polymer obtained in Synthesis Example 2 (degree of polymerization: 14
90, denaturation degree: 10.5 mol%) was added to 100 parts by mass of a 50% by mass methanol solution and mixed well, and a saponification reaction was carried out at 40 ° C. The obtained gel-like material was pulverized, washed well with methanol and then dried to obtain a saponified product of diacetone acrylamide-vinyl acetate copolymer having a saponification degree of 95.5 mol%.

50 parts of the above-mentioned diacetone acrylamide-vinyl acetate copolymer saponified product was added to 200 parts by weight of methanol.
In addition to the mass part, it was made to soak. Furthermore, 0.8 parts by mass of γ-aminopropyltrimethoxysilane (0.5 mol% based on the vinyl acetate polymer) was added, and methanol was evaporated in a dryer at 60 ° C. to give a vinyl alcohol polymer. Obtained.

Using the obtained aqueous solution of the vinyl alcohol polymer, the adhesion to the silica vapor deposition film and the binder force to the particulate silica were evaluated. As shown in Table 2, the adhesiveness and the binder strength were high, and the silica compound showed a high binding property.

Example 9 Vinyl acetate polymer obtained in Synthesis Example 2 (degree of polymerization: 14
90, 10.5 mol%) 50 mass% methanol solution 1
A 4% methanol solution of sodium hydroxide was added to 00 parts by mass and mixed well, and a saponification reaction was carried out at 40 ° C. The obtained gel-like substance was pulverized, washed well with methanol and then dried to obtain a saponified product of diacetone acrylamide-vinyl acetate copolymer having a saponification degree of 98.5 mol%.

50 parts of the above diacetone acrylamide-vinyl acetate copolymer saponified product was added to 200 parts by weight of methanol.
A mass part was added and it was made to immerse. Further, 16.3 parts by mass of γ-aminopropyltriethoxysilane (8.5 mol% based on vinyl acetate-based polymerization) was added, and methanol was evaporated in a dryer at 60 ° C. to obtain a vinyl alcohol-based polymer. It was

Using the aqueous solution of the obtained vinyl alcohol polymer, the adhesion to the silica vapor deposition film and the binder force for the particulate silica were evaluated. As shown in Table 2, the adhesiveness and the binder strength were high, and the silica compound showed a high binding property.

Comparative Example 1 A vinyl alcohol polymer was prepared in the same manner as in Example 1 except that γ-aminopropyltrimethoxysilane was not used, and the aqueous solution thereof was used to obtain adhesion to a silica vapor deposition film and particle shape. The binder strength on silica was evaluated. As shown in Table 2, adhesiveness and binder strength are low,
The binding property to the silica compound did not reach a practical level.

Comparative Example 2 A vinyl alcohol polymer was prepared in the same manner as in Example 6 except that γ-aminopropyltrimethoxysilane was not used, and the aqueous solution thereof was used to provide adhesion to a silica vapor deposition film and particle shape. The binder strength on silica was evaluated. As shown in Table 2, adhesiveness and binder strength are low,
The binding property to the silica compound did not reach a practical level.

Comparative Example 3 The amount of γ-aminopropyltrimethoxysilane added was 5.
A vinyl alcohol-based polymer was prepared in the same manner as in Example 1 except that the content was changed from 0 part by mass to 0.05 part by mass (0.05 mol% with respect to the vinyl acetate-based polymer). , The adhesion to the silica vapor deposition film, and the binder force to the particulate silica were evaluated. As shown in Table 2, as compared with the examples, the adhesiveness and the binder force are low,
The binding property to the silica compound did not reach a practical level.

Comparative Example 4 Instead of the vinyl acetate polymer obtained in Synthesis Example 1, the vinyl acetate polymer obtained in Comparative Synthesis Example 1 (degree of polymerization: 171)
(0, modification degree: 0.05 mol%) except that the vinyl alcohol polymer was prepared in the same manner as in Example 1 and the aqueous solution thereof was used to obtain the adhesion to the silica vapor deposition film and to the particulate silica. The binder strength was evaluated. As shown in Table 2, the adhesiveness and the binder strength were low as compared with the examples, and the binding property to the silica compound did not reach the practical level.

Comparative Example 5 Instead of the vinyl acetate polymer obtained in Synthesis Example 1, the unmodified polyvinyl acetate obtained in Comparative Synthesis Example 2 (degree of polymerization: 16
90, modification degree: 0 mol%) except that a vinyl alcohol polymer was prepared in the same manner as in Example 1 and the aqueous solution thereof was used to provide adhesion to a silica vapor deposition film and a binder force for particulate silica. Was evaluated. As shown in Table 2, the adhesiveness and the binder strength were low, and the binding property to the silica compound did not reach the practical level.

Comparative Example 6 Vinyl alcohol was used in the same manner as in Example 1 except that γ-glycidoxypropyltrimethoxysilane (silane coupling agent having no amino group) was used in place of γ-aminopropyltrimethoxysilane. A polymer was prepared, and its aqueous solution was used to evaluate the adhesiveness to the silica vapor deposition film and the binder force to the particulate silica. As shown in Table 2, the adhesiveness and the binder strength were low, and the binding property to the silica compound did not reach the practical level.

[0060]

[Table 2]

[0061]

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to obtain a silanol group-containing vinyl alcohol polymer having an excellent binding property with a silica compound by an industrially advantageous method, and obtain the obtained silanol group. The containing polymer is practically useful as a coating agent for a thermoplastic film having a silica vapor deposition layer capable of improving the performance by increasing the binding property with a silica compound, a binder for an inkjet printer substrate, and the like. It can be effectively applied to various uses.

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Claims (3)

[Claims] 1. A vinyl alcohol-based polymer characterized by containing 0.1 to 15 mol% of a constitutional unit represented by the following chemical formula 1 in a copolymer mainly composed of vinyl alcohol structural units. [Chemical 1] (An integer of x = 0 to 3, y = 0 to 1, z = 1 to 5, R ₁ ..
R ₂ represents a hydrogen atom, a methyl group or an ethyl group, and R ₃ represents a hydrogen atom, a hydroxyl group, a methyl group, an ethyl group, a methoxy group or an ethoxy group. ) 2. A fatty acid vinyl ester copolymer having a diacetone acrylamide unit and a silane coupling agent having an amino group are reacted in a methanol solvent,
A method for producing a vinyl alcohol-based polymer, which comprises saponifying. 3. A method for producing a vinyl alcohol-based polymer, which comprises reacting a saponified product of diacetone acrylamide-fatty acid vinyl ester copolymer with a silane coupling agent having an amino group in a methanol solvent.