JP2002275338A - Resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a PVA resin composition containing a silanol group which is excellent in a binding property with a silica compound and obtained by an industrially advantageous method. SOLUTION: This resin composition comprises (A) a PVA resin, (B) a polyvalent metal salt such as aluminum sulfate, etc., and (C) a silane coupling agent having an epoxy group. The PVA resin is desirably a partially saponified polyvinyl alcohol having a degree of saponification of 85-90 mole % and a saponified product of a diacetone acrylamide-aliphatic acid vinyl ester copolymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition having excellent binding properties with a silica compound.

[0002]

2. Description of the Related Art Polyvinyl alcohol (hereinafter abbreviated as PVA) resins have high film-forming properties, and are excellent in binding properties and gas barrier properties, so that they can be used in a wide range of applications such as films, coating films and binders. Is used, for example, a laminated film obtained by forming a coating film of a PVA-based resin on a thermoplastic resin film having a silica vapor deposition layer,
It has advantages such as high gas barrier properties and no generation of toxic gas when incinerated and discarded. In recent years, attention has been paid to environmental issues as well. However, since the adhesion between the silica-deposited layer and the PVA coating film is not high, the silica-deposited layer and the PVA
There is a problem that the coating film peels off. In addition, although a particulate silica is used as an ink absorbent and a PVA-based resin is used as a binder for an ink jet printer substrate, there are problems such as insufficient surface strength of the obtained substrate. . These problems are caused by insufficient binding force between the PVA-based resin and the silica compound in any application, and are considered to be solved by introducing silanol groups into PVA.

[0003] PVA into which such silanol groups are introduced
Regarding the series resin, JP-A-58-59203 and JP-A-58-164604 disclose a production method in which a vinyl monomer having an alkoxysilyl group and vinyl acetate are copolymerized and saponified. It has been disclosed that the silanol group-containing PVA-based resin obtained by this method has a high binding property with a silica compound, and an effect of improving the performance is seen in applications using the silica compound and the PVA resin.

However, since the polymerization rate at the time of copolymerizing a monomer having an alkoxysilyl group with a fatty acid vinyl ester such as vinyl acetate is low, the production rate is low and the unreacted alkoxysilyl group after polymerization is reduced. There is a problem that removal of the monomer is difficult because a large amount of the monomer remains. Further, the alkoxysilyl group is expensive, and there is a problem that the cost of the obtained silanol group-containing PVA-based resin is high. Therefore, a PVA-based resin containing a silanol group obtained by an industrially advantageous method has been demanded.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned drawbacks of the prior art, has excellent binding properties with silica compounds, and can be obtained by an industrially advantageous method. It is another object of the present invention to provide a PVA-based resin composition useful as a coating material for a thermoplastic film having a silica vapor-deposited layer, a binder for a substrate for an inkjet printer, and the like.

[0006]

SUMMARY OF THE INVENTION The present invention achieves the above object and comprises (A) a PVA-based resin, (B) a polyvalent metal salt and (C) a silane coupling agent having an epoxy group. Wherein the polyvalent metal salt is desirably aluminum sulfate, and the PVA-based resin is partially saponified PVA having a saponification degree of 85 to 90 mol% or It is preferably a saponified product of an acetone acrylamide-fatty acid vinyl ester copolymer.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

[0008] PV used as component (A) of the present invention
Examples of the A-based resin include known unmodified PVA and various modified PVA.
A and the like, and are produced by saponifying a polymer obtained by polymerizing a fatty acid vinyl ester, and a copolymer obtained by copolymerizing a fatty acid vinyl ester and an ethylenically unsaturated monomer. be able to.

Examples of the fatty acid vinyl ester used in the above polymerization or copolymerization include vinyl formate, vinyl acetate, vinyl propionate and vinyl pivalate. Of these, vinyl acetate is industrially preferable and known bulk polymerization is used. It can be produced by various polymerization methods such as solution polymerization, suspension polymerization and emulsion polymerization. Among them, solution polymerization using methanol as a solvent is industrially preferable.

The ethylenically unsaturated monomers used in the copolymerization include unsaturated monocarboxylic acids such as crotonic acid, acrylic acid and methacrylic acid, and esters, salts, anhydrides, amides and nitriles thereof, and maleic acid. , Itaconic acid
Unsaturated dicarboxylic acids such as fumaric acid and salts thereof, monoalkyl esters of unsaturated dibasic acids such as monomethyl maleate and monomethyl itaconate, α- having 2 to 30 carbon atoms
Examples thereof include olefins, alkyl vinyl ethers, and vinyl pyrrolidones, and among them, a saponified diacetone acrylamide-fatty acid vinyl ester copolymer is preferable because it has a large effect of improving the binding property to a silica compound.

As a method for saponifying the obtained polymer or copolymer, known alkali saponification and acid saponification methods can be applied. Among them, a methanol solution of the polymer or methanol and water, acetic acid and acetic acid can be used. Industrially preferable is a method of adding an alkali hydroxide to a mixed solution of methyl, benzene, etc. to carry out alcoholysis.
Alternatively, a modified PVA-based resin obtained by post-modifying copolymerized modified PVA by acetalization, urethanization, etherification, grafting, phosphoric esterification, acetoacetylation, or the like may be used.

Although the degree of polymerization and the degree of saponification of the PVA-based resin are not particularly limited, unmodified PVA has a degree of saponification of 85 to 90.
The use of mol% of partially saponified PVA is preferable because the effect of improving the binding property to the silica compound is large.

Examples of the polyvalent metal salt used as the component (B) of the present invention include salts of aluminum, titanium, zirconium, magnesium and the like. More specifically, aluminum sulfate, ammonium aluminum sulfate, acetic acid Aluminum, aluminum chloride, aluminum fluoride, aluminum hydroxide, aluminum lactate, aluminum laurate, aluminum nitrate, aluminum oxide, aluminum perchlorate, aluminum phosphate,
Aluminum salts such as potassium aluminum sulfate, sodium aluminum sulfate, aluminum stearate, aluminum thiodiglycolate, aluminum trifluoride, trimethyl aluminum, aluminum isopropoxide, aluminum ethoxide, etc., and acidic aqueous solutions of aluminum, titanium chloride, and 2 boron Titanium iodide, titanium silicide, titanium ethoxide, titanium 2-ethyl-1-hexanolate, titanium hydride, titanium iodide, titanium oxide, potassium titanium fluoride, titanium potassium oxalate,
Titanium salts such as titanium sulfate, tetrabutoxytitanium and titanium tetraisopropoxide, and acidic aqueous solutions of titanium, zirconium chloride, zirconium carbide, zirconium diboride, zirconium chloride oxide, zirconium acetylacetonate, zirconium disilicide, and hydrogenated Zirconium salts such as zirconium, zirconium oxide, zirconium iodide, zirconium oxychloride, zirconium n-propoxide, zirconium oxychloride, zirconium tetrachloride, zirconium nitrate, and acidic aqueous solutions of zirconium, magnesium acetate, magnesium bromide, magnesium carbonate, Magnesium chloride, magnesium citrate, magnesium ethoxide, magnesium fluoride, magnesium hydroxide, magnesium lactate, magnesium myristate, Magnesium, magnesium oxalate, magnesium oxide, magnesium perchlorate,
Examples include, but are not limited to, magnesium salts such as magnesium phosphate, magnesium sulfate, magnesium silicate, and acidic aqueous solutions of magnesium. Among them, a water-soluble polyvalent metal salt has a high effect, and aluminum sulfate is particularly preferred.

As the silane coupling agent having an epoxy group used as the component (C) of the present invention, β-
(3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ
-Glycidoxypropylmethyldiethoxysilane and the like, and these can be used alone or in combination of two or more.

The amount of the polyvalent metal salt (B) to be added to the PVA resin (A) is preferably at least 0.1 part by mass, more preferably from 0.2 to 50 parts by mass, per 100 parts by mass of the PVA resin. Parts by mass, more preferably 0.5 to 2 parts by mass.
0 parts by mass. Further, the blending amount of the silane coupling agent (C) having an epoxy group is desirably 0.05 parts by mass or more based on 100 parts by mass of the PVA-based resin.
Preferably it is 0.1-50 mass parts, More preferably, it is 0.2-20 mass parts. In the present invention, it is important that both the polyvalent metal salt (B) and the silane coupling agent (C) having an epoxy group are blended with the PVA resin (A). If not, there is no effect.

The resin composition of the present invention is prepared and used as an aqueous solution or an aqueous dispersion. The preparation method is not particularly limited. For example, an aqueous solution or aqueous dispersion of a polyvalent metal salt and an undiluted solution, aqueous solution or aqueous dispersion of a silane coupling agent having an epoxy group are added to an aqueous solution of a PVA-based resin prepared in advance. A method of adding a liquid and stirring at room temperature or heating, or a method of adding a polyvalent metal salt and a silane coupling agent having an epoxy group when dissolving the PVA-based resin in water.
The order of adding the polyvalent metal salt and the silane coupling agent having an epoxy group to the A-based resin is not particularly limited, and the effect is not changed.

When preparing an aqueous solution or aqueous dispersion of the resin composition of the present invention, if necessary, cellulose derivatives such as starch, methylcellulose, carboxymethylcellulose, polyacrylic acid derivatives, other natural polymers such as gelatin, Synthetic polymers, clay, kaolin, talc, silica, inorganic fillers such as calcium carbonate, glycerin, plasticizers such as sorbitol, surfactants, defoamers, antistatic agents, chelating agents, crosslinking agents, etc. It can be blended within a range that does not impair the effect.

Although the reason why the resin composition of the present invention exhibits a high binding property to a silica compound has not been sufficiently elucidated, the reaction between the hydroxyl group of the PVA-based resin and the epoxy group of the silane coupling agent has not been elucidated. In the above, it is considered that the reaction proceeds at room temperature or in the presence of water due to the polyvalent metal salt acting as a reaction accelerator, and a silanol group is added to the PVA-based resin.

[0019]

Next, the present invention will be described specifically with reference to examples. In addition, the evaluation about the obtained resin composition was performed by the following method.

[0020] Evaluation of Adhesion to Silica-Deposited Film A 5% by mass aqueous solution of a PVA-based resin composition was cast on a deposition surface of a polyethylene terephthalate film (thickness: 12 μm) that had been subjected to a silica deposition treatment, and the conditions were 20 ° C. and 65% RH For 24 hours to form a coating film having a thickness of about 50 μm.
The silica-deposited film having the PVA-based resin composition coating film was cut into a size of 100 mm × 20 mm, and the peel strength between the 20-mm-wide coating film and the silica-deposited film was measured with a strograph manufactured by Toyo Seiki.

[0021] Evaluation of Binder Strength for Particulate Silica To 100 parts by weight of a 5% by weight aqueous solution of a PVA-based resin composition, 20 parts by weight of particulate silica and 50 parts by weight of pure water were added, and the mixture was stirred at room temperature using a homomixer (stirring speed: 10,000 rpm). For 5 minutes to prepare a coating solution. No. on copy paper (Ricoh, My Recycled Paper New) About 10 g / m ^{2 of the} above-mentioned coating solution was applied using a bar coater No. 40.
(Solid content) and dried at 105 ° C. for 120 seconds using a drum dryer. After sticking a Nichiban cellophane adhesive tape (width: 18 mm) to the coated paper thus obtained, the peel strength was measured with a stryograph manufactured by Toyo Seiki.

[0022] Comprehensive evaluation The evaluation results of the adhesion to the silica-deposited film and the binder power to the particulate silica were comprehensively determined as the binding property to the silica compound, and evaluated according to the following criteria. A: Very good binding to silica compounds. ：: Excellent in binding to silica compound, at practical level. X: The binding property to the silica compound has not reached a practical level.

Example 1 As shown in Table 1, the degree of polymerization was 1780 and the degree of saponification was 88.0.
100 parts by mass of a 10% by mass aqueous solution of 10% by mass of unmodified PVA, 10 parts by mass of 2% by mass aqueous solution of aluminum sulfate,
0.5% by mass of glycidoxytrimethoxysilane and pure water were added to prepare a 5% by mass aqueous solution of a PVA-based resin composition. About the obtained PVA-based resin composition aqueous solution,
When the adhesion of the silica-deposited layer film and the binder power to the particulate silica were evaluated, as shown in Table 2, it was excellent in adhesion and binder power, and showed high binding properties to the silica compound.

Examples 2 to 9 Types of PVA resin (degree of polymerization, degree of saponification, presence or absence of modification,
Degree of modification), a 5% by mass aqueous solution of a PVA-based resin composition in the same manner as in Example 1 except that the type and amount of the polyvalent metal salt, the type and the amount of the silane coupling agent were changed as shown in Table 1. Was prepared. When the adhesiveness to the silica vapor-deposited film and the binder power to the particulate silica were evaluated, as shown in Table 2, each of them was excellent in adhesiveness and binder power, and showed high binding properties to the silica compound. .

Comparative Example 1 As shown in Table 1, a 5% by mass aqueous PVA solution was prepared in the same manner as in Example 1 except that aluminum sulfate and γ-glycidoxytrimethoxysilane were not used. When the adhesiveness to the silica-deposited film and the binder power to the particulate silica were evaluated, as shown in Table 2, the adhesiveness and the binder power were inferior, and the binding property to the silica compound did not reach a practical level.

Comparative Example 2 As shown in Table 1, 5% by mass was obtained in the same manner as in Example 1 except that γ-glycidoxytrimethoxysilane was not used.
Of a PVA-based resin composition aqueous solution was prepared. When the adhesiveness to the silica-deposited film and the binder power to the particulate silica were evaluated, as shown in Table 2, the adhesiveness and the binder power were inferior, and the binding property to the silica compound did not reach a practical level.

Comparative Example 3 As shown in Table 1, a 5% by mass aqueous solution of a PVA-based resin composition was prepared in the same manner as in Example 1 except that aluminum sulfate was not used. Adhesion to silica deposited film,
When the binder for the particulate silica was evaluated, as shown in Table 2, the adhesiveness and the binder strength were inferior,
The binding property to the silica compound did not reach a practical level.

Comparative Example 4 As shown in Table 1, γ-aminopropyltrimethoxysilane (a silane coupling agent having no epoxy group) was used in place of γ-glycidoxytrimethoxysilane. In the same manner as in Example 1, a 5% by mass aqueous solution of a PVA-based resin composition was prepared. When the adhesiveness to the silica-deposited film and the binder power to the particulate silica were evaluated, as shown in Table 2, the adhesiveness and the binder power were inferior, and the binding property to the silica compound did not reach a practical level.

[0029]

[Table 1]

[0030]

[Table 2]

[0031]

According to the present invention, it is possible to obtain a silanol group-containing PVA-based resin composition which is excellent in binding property with a silica compound and which can be obtained by an industrially advantageous method. Can be suitably used, for example, as a coating agent for a thermoplastic film having a silica vapor-deposited layer, a binder for a substrate for an inkjet printer, and the like.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J002 BE021 DB01 DD03 DD07 DD08 DE06 DE07 DE09 DE14 DE19 DE23 DF03 DG046 DH04 DJ00 DK00 EC07 EE04 EG03 EG04 EG05 EV06 EX067 EZ00 GH00

Claims (4)

[Claims] 1. A resin composition comprising (A) a polyvinyl alcohol resin, (B) a polyvalent metal salt, and (C) a silane coupling agent having an epoxy group. 2. The resin composition according to claim 1, wherein the polyvalent metal salt is aluminum sulfate. 3. The resin composition according to claim 1, wherein the polyvinyl alcohol resin is a partially saponified polyvinyl alcohol having a saponification degree of 85 to 90 mol%. 4. The polyvinyl alcohol-based resin is a saponified product of a diacetone acrylamide-fatty acid vinyl ester copolymer.
The resin composition as described in the above.