JP2007269882A - Water-resistant composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water-resistant composition that can give a film having excellent water resistance and transparency and retains excellent storage stability. <P>SOLUTION: The water-resistant composition comprises a polymer (A) including at least 5 wt.% of a vinyl monomer unit bearing acetoacetyl group and a polymer (B) of vinyl alcohol wherein the weight ratio of (A)/(B) is 2/100 to 200/100, and a water-resisting agent (b) is added to the water-based resin including (A) bonding to (B) in an amount of more than 50% based on the total weight of (A) or its aqueous dispersion (a). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a water-resistant composition that can provide a film excellent in water resistance and transparency even when dried at room temperature and has excellent storage stability.

  Conventionally, vinyl alcohol polymers (hereinafter, vinyl alcohol polymers may be abbreviated as PVA) have been widely used as various binders, adhesives, or surface treatment agents. It is known to have excellent performance that does not allow the following water-soluble resin to follow. However, since PVA is water-soluble, there is a drawback that water resistance, particularly when it is dried at a low temperature (room temperature), is low, and various methods have been studied in order to improve this drawback. . As one of the methods, for example, a method of crosslinking PVA with glyoxal, glutaraldehyde or 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 a heat treatment for a long time at a high temperature of 100 ° C. or higher, particularly 120 ° C. or higher. In addition, in order to make PVA water resistant by low temperature drying, it is also known to use strongly acidic conditions such as pH 2 or lower. However, in this case, the viscosity stability of the PVA aqueous solution is deteriorated, and during use. It has the disadvantage that it causes gelation and the like, and furthermore, the water resistance is insufficient. Furthermore, a method of crosslinking a carboxyl group-containing PVA with a polyamide epichlorohydrin resin is also known, but this method also has problems such as insufficient water resistance and poor viscosity stability of the PVA aqueous solution. .

A method of crosslinking an acetoacetyl group-containing PVA obtained by reacting a diketene with a hydroxyl group of PVA with a polyvalent aldehyde compound such as glyoxal is also known (Patent Document 1), but the reaction conditions with diketene are limited. Or the stability of the resulting acetoacetyl group-containing PVA aqueous solution is poor. For the purpose of solving these problems, for example, a method for controlling the iron content in the acetoacetyl group-containing PVA (Patent Document 2), a method for controlling the acetate and acetic acid content (Patent Document 3), etc. Although it has been proposed, it is hard to say that both methods are sufficiently satisfactory.
Japanese Patent Application Laid-Open No. 55-157441 JP-A-9-77948 JP-A-9-124874

  An object of the present invention is to provide a water-resistant composition that eliminates the drawbacks of the above-described prior art, provides a film that is excellent in water resistance even when dried at room temperature, and is excellent in storage stability. Is.

  The above-mentioned problem consists of a polymer (A) containing at least 5% by weight of a vinyl monomer unit having an acetoacetyl group and a vinyl alcohol polymer (B), and the weight ratio (A) / (B) is 2/100 to 200/100, and the weight ratio of (A) bound to (B) is 50% or more based on the total weight of (A), or a water-resistant agent (b) ) To achieve the water-resistant composition.

  According to the present invention, a film having excellent water resistance and transparency can be obtained even when drying at room temperature, and a water resistant composition having excellent storage stability can be obtained.

  In the present invention, examples of the vinyl monomer having an acetoacetyl group include acetoacetoxyethyl (meth) acrylate, acetoacetoxyethyl (meth) acrylamide, acetoxyethyl allyl ether, acetoxyethyl vinyl ether, and particularly acetoacetoxyethyl (meth). Acrylate is preferably used.

  In the present invention, it is necessary to use a polymer (A) containing at least 5% by weight of the above-mentioned vinyl monomer unit having an acetoacetyl group with respect to all monomers. If it is less than 5% by weight, a film excellent in water resistance cannot be obtained even in the intended drying at room temperature. The preferred content of vinyl monomer units having an acetoacetyl group is 10 to 100% by weight, optimally 20 to 100% by weight. The monomer copolymerized with a vinyl monomer having an acetoacetyl group is not particularly limited as long as it is copolymerizable with a vinyl monomer having an acetoacetyl group, and α such as ethylene, propylene, n-butene, isobutylene, etc. -Olefin; acrylic acid and salts thereof, methyl acrylate, ethyl acrylate, n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, i-butyl acrylate, t-butyl acrylate, acrylic acid 2 Acrylic esters such as ethylhexyl, dodecyl acrylate, octadecyl acrylate; methacrylic acid and its salts, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, i-propyl methacrylate, n-butyl methacrylate, methacryl I-Butyl acid, methacrylic acid t Methacrylic acid esters such as butyl, 2-ethylhexyl methacrylate, dodecyl methacrylate, octadecyl methacrylate; acrylamide, N-methyl acrylamide, N-ethyl acrylamide, N, N-dimethyl acrylamide, diacetone acrylamide, acrylamide propane sulfonic acid and Acrylamide derivatives such as salts thereof, acrylamidopropyldimethylamine and salts thereof or quaternary salts thereof, N-methylolacrylamide and derivatives thereof; methacrylamide, N-methylmethacrylamide, N-ethylmethacrylamide, methacrylamidepropanesulfonic acid and the like Salts, methacrylamidopropyldimethylamine and salts thereof or quaternary salts thereof, N-methylol methacrylamide and derivatives thereof, etc. Methacrylamide derivatives of; 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; acrylonitrile, methacrylo Nitriles such as nitriles, vinyl halides such as vinyl chloride and vinyl fluoride, vinylidene halides such as vinylidene chloride and vinylidene fluoride; allyl compounds such as allyl acetate and allyl chloride; maleic acid and its salts or esters thereof; vinyl Examples include vinylsilyl compounds such as trimethoxysilane; isopropenyl acetate and the like.

  There is no restriction | limiting in particular about the saponification degree of PVA (B) used in this invention, Usually, it is 80 mol% or more, Preferably it is 85 mol% or more, More preferably, it is 88 mol% or more. When the degree of saponification is less than 80 mol%, the effect of improving the water resistance of the target film may not be exhibited. Moreover, there is no restriction | limiting in particular also about the polymerization degree of PVA (B), Usually, it is 100-8000, Preferably it is 200-3000, More preferably, it is 250-2500. When the degree of polymerization of PVA is less than 100, the characteristics of PVA as a dispersion stabilizer may not be exhibited, and PVA exceeding 8000 may be accompanied by difficulty in industrial production.

  In the present invention, PVA (B) can be obtained by polymerizing a vinyl ester monomer and saponifying the resulting polymer by a conventional method according to a conventionally known method. As a method for polymerizing the vinyl ester monomer, conventionally known methods such as a solution polymerization method, a bulk polymerization method, a suspension polymerization method, and an emulsion polymerization method can be employed. As the polymerization catalyst, an azo-based catalyst, a peroxide-based catalyst, a redox-based catalyst, or the like is appropriately selected according to the polymerization method employed. The saponification reaction may employ alcoholysis or hydrolysis using a conventionally known alkali catalyst or acid catalyst. Specifically, methanol is used as a solvent and the saponification reaction is performed in the presence of a NaOH catalyst. Is simple and most preferred.

  Examples of vinyl ester monomers include vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl versatate, vinyl caproate, vinyl caprylate, vinyl laurate, and palmitic acid. Examples thereof include vinyl, vinyl stearate, vinyl oleate, vinyl benzoate and the like, and vinyl acetate is particularly preferable.

  Moreover, PVA (B) used in this invention may contain another monomer unit in the range which does not impair the main point of this invention. Examples of such a monomer include monomers similar to those exemplified as the monomer copolymerized with the above-described vinyl monomer having an acetoacetyl group, such as α-olefin.

As PVA (B), it is preferable to use a vinyl alcohol polymer (sometimes abbreviated as α-olefin-modified PVA) containing 1 to 20 mol% of an α-olefin unit having 4 or less carbon atoms in the molecule. It is one of. By using the α-olefin-modified PVA, the water resistance of the aqueous resin or the aqueous dispersion (a) used in the present invention is further improved. The α-olefin-modified PVA can be obtained by saponifying a copolymer of a vinyl ester and an α-olefin having 4 or less carbon atoms. Here, examples of the α-olefin unit having 4 or less carbon atoms include units derived from ethylene, propylene, butylene, isobutylene and the like, and among these, ethylene units are preferably used.
The content of α-olefin units represented by ethylene units is preferably 1 to 20 mol%, more preferably 1.5 mol% or more, still more preferably 2 mol% or more, and preferably Is 15 mol% or less, more preferably 12 mol% or less. When α-olefin-modified PVA having an α-olefin unit typified by an ethylene unit in this range is used, an aqueous resin having excellent water resistance or an aqueous dispersion (a) thereof can be obtained.

Furthermore, in the present invention, it is also preferable to use PVA having a 1,2-glycol bond amount of 1.9 mol% or more (sometimes abbreviated as high 1,2-glycol bond-containing PVA) as PVA. One. By using high 1,2-glycol bond-containing PVA, the proportion of (A) bound to (B) increases.
There is no restriction | limiting in particular as a manufacturing method of high 1, 2- glycol bond containing PVA, A well-known method can be used. As an example, a method in which vinylene carbonate is copolymerized with a vinyl ester so that the 1,2-glycol bond amount is within the above range, and the vinyl ester is added at a temperature higher than normal conditions, for example, 75 to 200 ° C. Examples include a method of polymerizing under pressure. In the latter method, the polymerization temperature of the vinyl ester is preferably 95 to 190 ° C, particularly preferably 100 to 180 ° C. Moreover, it is important to select the pressurizing condition such that the polymerization system is lower than the boiling point, preferably 0.2 MPa or more, and more preferably 0.3 MPa or more. Moreover, the upper limit of pressurization is preferably 5 MPa or less, and more preferably 3 MPa or less. Polymerization of the vinyl ester can be carried out by any method such as bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization in the presence of a radical polymerization initiator, but solution polymerization, particularly methanol as a solvent. A solution polymerization method is preferred. High vinyl 1,2-glycol bond-containing PVA is obtained by saponifying the vinyl ester polymer thus obtained by a conventional method. The 1,2-glycol bond amount of PVA is preferably 1.9 mol% or more, more preferably 1.95 mol% or more, further preferably 2.0 mol% or more, and optimally 2.1. More than mol%. The amount of 1,2-glycol bonds is preferably 4 mol% or less, more preferably 3.5 mol% or less, and most preferably 3.2 mol% or less. Here, the amount of 1,2-glycol bonds of PVA can be determined by analyzing the NMR spectrum.

  In the present invention, the weight ratio (A) / (B) of the polymer (A) having a vinyl monomer unit having an acetoacetyl group and PVA (B) needs to be 2/100 to 200/100, It is preferably 5/100 to 150/100, more preferably 8/100 to 120/100, and most preferably 10/100 to 100/100. When the weight ratio (A) / (B) is less than 2/100, sufficient water resistance cannot be imparted to the composition. On the other hand, when the weight ratio of (A) and (B) is 200/100 or more, the storage stability of the resulting water-resistant composition is lowered.

  In the present invention, the ratio of the polymer (A) having a vinyl monomer unit having an acetoacetyl group bonded to PVA (B) {the weight ratio of (A) bonded to (B) to the total weight of (A) } (Hereinafter referred to as the bond ratio of (A)) is also required to be 50% or more, preferably 60% or more, more preferably 70% or more, and most preferably 80% or more. When the binding ratio of (A) is less than 50%, sufficient water resistance cannot be imparted to the composition, and the storage stability is not sufficiently excellent. Here, the bonding ratio of (A) is measured by the method described in Example 1 described later.

  The aqueous resin used in the water-resistant composition of the present invention is used as an aqueous solution or an aqueous dispersion, but when used as an aqueous dispersion, the particle diameter of the aqueous resin is measured by a dynamic light scattering method. The thickness is preferably 500 nm or less, preferably 400 nm or less, more preferably 300 nm or less, and most preferably 200 nm or less. When the particle diameter exceeds 500 nm, there is a concern that the storage stability of the resulting water-resistant composition is lowered. The lower limit of the particle diameter of the aqueous resin is not particularly limited, but is preferably 20 nm or more, and more preferably 50 nm or more. The measurement by the dynamic light scattering method can be performed using, for example, a laser zeta electrometer ELS-8000 manufactured by Otsuka Electronics Co., Ltd. The particle diameter of the aqueous resin is the weight ratio of (A) and (B), and further the production conditions of the aqueous resin (polymerization temperature, polymerization time, monomer, polymerization initiator, addition timing of dispersant, chain transfer agent It can be adjusted by appropriately selecting the amount used).

  The method for producing the aqueous resin or the aqueous dispersion (a) thereof used in the water-resistant composition of the present invention is not particularly limited. For example, an aqueous solution of PVA (B) is used as a dispersant, and a vinyl monomer having an acetoacetyl group is used. Examples of the method include emulsion polymerization by adding a polymerization initiator such as peroxide such as hydrogen peroxide, ammonium persulfate, or potassium persulfate, temporarily or continuously. The polymerization initiator may be used as a redox system in combination with a reducing agent. In that case, hydrogen peroxide is usually used together with tartaric acid, sodium tartrate, L-ascorbic acid, Rongalite and the like. Ammonium persulfate and potassium persulfate are used together with sodium hydrogen sulfite, sodium hydrogen carbonate and the like. Among them, hydrogen peroxide is preferably used because the above-mentioned (A) binding ratio increases when a vinyl monomer having an acetoacetyl group is emulsion-polymerized using the hydrogen peroxide.

There is no restriction | limiting in particular as a water-proofing agent (b) used for the water-resistant composition of this invention, The at least 1 sort (s) of water-proofing agent chosen from a hydrazide compound, an amine compound, and a polyvalent metal compound is suitable. Of these, hydrazide compounds are preferably used from the viewpoints of safety and water resistance of the composition.
Examples of the hydrazide compound include adipic acid dihydrazide, oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, azelaic acid dihydrazide, sebacic acid dihydrazide, dodecanedioic acid dihydrazide, maleic acid dihydrazide, diglycolic acid dihydride diglycolic acid Examples thereof include dihydrazide compounds such as malic acid dihydrazide, isophthalic acid dihydrazide, and terephthalic acid dihydrazide.
Examples of amine compounds include ethylenediamine, 1,2-propylenediamine, 1,3-propylenediamine, 1,4-butylenediamine, hexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, diethylenetriamine, dipropylenetriamine, Aliphatic polyamines such as ethylenetriamine, tetraethylenepentamine, dipropylenetriamine, dimethylaminopropylamine, diethylaminopropylamine; mensendiamine, 1,3-bis (aminomethyl) cyclohexane, isophoronediamine, N-3-amino Propylcyclohexylamine, 1,4-diaminocyclohexane, 2,4-diaminocyclohexane, bis (aminocyclohexyl) methane, 1,3-bis (aminocyclohexylpropane), Cycloaliphatic polyamines such as s (3-methyl-4-aminocyclohexyl) methane and 1,4-bis (ethylamino) cyclohexane; m-xylylenediamine, p-xylylenediamine, 4- (1-aminoethyl) ) Aniline, metaphenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, bis (3-ethyl-4-amino-5-methylphenylmethane), 1,4-bis [2- (3,5-dimethyl-4-aminophenyl) ) Propyl] aromatic polyamines such as benzene; polyamine-based curing agents such as heterocyclic polyamines such as N-aminoethylpiperazine and 1,4-bis (3-aminopropyl) piperazine; these polyamines and dimer acid, etc. Polyamine curing agent obtained by reacting the dicarboxylic acid of Etc., and the like.
Examples of the polyvalent metal compounds include ammonium zirconium carbonate, zirconium oxychloride, zirconium sulfate, zirconium nitrate, zirconium acetate, zirconium carbonate, zirconium stearate, zirconium octylate, zirconium silicate and the like, and titanium lactate and part thereof or completely Japanese products (eg, titanium lactate monoammonium salt, titanium lactate diammonium salt, titanium lactate monosodium salt, titanium lactate disodium salt, titanium lactate monopotassium salt, titanium lactate dipotassium salt), dihydroxytitanium bislactate, diisopropoxytitanium bis (Triethanolaminate), di-n-butoxytitanium bis (triethanolaminato), diisopropoxytitanium bis ( Acetylacetonate), titanium tetrakis (acetylacetonate), and an organic titanium compound such Porichitanbisu (acetylacetonate).

  There is no particular limitation on the weight ratio [(a) / (b)] (in terms of solid content) of the aqueous resin or its aqueous dispersion (a) and the water-resistant agent (b), and usually 99.9 / 0.00. It is 1-50 / 50, Preferably it is 99.5 / 0.5-70 / 30. When (a) / (b) exceeds 99.9 / 0.1, the resulting water-resistant composition may not exhibit the effect of improving water resistance. There is a concern that the storage stability of the composition may decrease.

  The water-resistant composition of the present invention may contain a solvent, various additives, other water-soluble resins, polymer aqueous dispersions, and the like as necessary. As the solvent, water is preferably used, and various alcohols, ketones, dimethylformamide, dimethyl sulfoxide and the like can be used in combination, and the additives include various antifoaming agents, various dispersing agents, nonionic or anionic. Surfactants, silane coupling agents, pH adjusters, and fillers such as calcium carbide, clay, talc, and flour. Examples of water-soluble resins include cellulose derivatives such as carboxymethyl cellulose and hydroxyethyl cellulose, poly (meth) acrylic acid, polyhydroxy (meth) acrylate or copolymers thereof, (meth) acrylic polymers such as polyacrylamide, polyvinylpyrrolidone or the like A copolymer etc. are mentioned. Examples of the high molecular weight aqueous dispersion include aqueous dispersions such as acrylic polymers or copolymers, ethylene-vinyl acetate copolymers, vinyl ester polymers or copolymers, and styrene-butadiene copolymers.

  The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. In the following examples, “%” and “part” mean “% by weight” and “part by weight” unless otherwise specified.

Example 1
In a glass polymerization vessel having a capacity of 2 liters equipped with a reflux condenser, a thermometer, and a nitrogen inlet, 900 g of ion-exchanged water, polyvinyl alcohol (PVA-1: polymerization degree 1700, saponification degree 98.5 mol%: Corporation) 100% of Kuraray PVA-117) was charged, and PVA was completely dissolved in water at 95 ° C. The PVA aqueous solution thus obtained was cooled and replaced with nitrogen, and then the temperature was adjusted to 60 ° C. while stirring at 130 rpm, and 25 g of acetoacetoxyethyl methacrylate and 5 g of a 10% aqueous solution of sodium tartrate were charged. . Thereafter, 50 g of 0.5% aqueous hydrogen peroxide was continuously added dropwise over 3 hours to carry out emulsion polymerization. After 3 hours, an aqueous resin dispersion having a solid content of 11.96% (acetoacetoxyethyl methacrylate polymerization rate of 99.7%) was obtained.
A water-resistant composition was prepared by adding 9.8 parts by weight of adipic acid dihydrazide as a water-resistant agent to 100 parts by weight of the solid content of the aqueous resin dispersion.
The aqueous resin and the water resistant composition were evaluated by the following methods. The results are shown in Table 1.

(1) Measurement of particle diameter The aqueous resin was diluted to 0.05% with ion-exchanged water, and the DLS average particle diameter was measured using ELS-8000 manufactured by Otsuka Electronics.
(2) Bonding ratio of component (A) The aqueous resin was cast on a PET film at 20 ° C. and 65% RH, and dried for 7 days to obtain a film having a thickness of 500 μm. A sample obtained by punching out this film into a disk shape having a diameter of 2.5 cm was used as a sample, soxhlet extracted with acetone for 24 hours, and the binding ratio of the component (A) was determined from the extract according to the following formula.
(A) Component binding ratio (%) = {1− (absolute dry weight of extract / total weight of component (A) in film sample)} × 100
* Absolute dry weight of the extract: The weight of the extract dried at 105 ° C. for 4 hours.
(3) Storage stability of water-resistant composition The water-resistant composition was allowed to stand at 40 ° C for 1 week, visually observed for changes in viscosity, and evaluated according to the following criteria.
○: No change in viscosity, △: Fluidity but slightly thickening, X: Gelation (4) Water resistance of the film of the water resistant composition The water resistant composition is 20 ° C and 65% RH, The film was cast on a polyethylene terephthalate (hereinafter abbreviated as PET) film and dried at room temperature for 7 days to obtain a 500 μm film. A sample obtained by punching this film into a disk shape having a diameter of 2.5 cm was used as a sample, and the water absorption rate and elution rate of the film when immersed in water at 40 ° C. for 24 hours were determined according to the following equations.
Water absorption rate (%): {(water absorption weight of the film after immersion / absolute dry weight of the film before immersion) -1} × 100
Elution rate (%): {1- (absolute dry weight of film after immersion / absolute dry weight of film before immersion)} × 100
* Absolutely dry weight of film before immersion: Weight of film before immersion (water content)-{weight of film before immersion (water content) x moisture content of film (%) / 100}
* Moisture content of the film: The film (a sample different from the sample immersed in water at 20 ° C.) is completely dried at 105 ° C. for 4 hours, and the moisture content of the film is obtained in advance.
* Absolutely dry weight of the film after immersion: The weight of the film after immersion completely dried at 105 ° C. for 4 hours.
* Water absorption weight of the film after immersion: After lifting the film after immersion from the water, wipe the moisture on the film with gauze and weigh.
(5) Transparency of film of water-resistant composition A film having a thickness of 500 μm was obtained in the same manner as (4) described above. The transparency of the film was visually evaluated according to the following criteria.
○: Transparent, △: Slightly cloudy, ×: Cloudy

Example 2
An aqueous resin dispersion and a water-resistant composition were prepared and evaluated in the same manner as in Example 1 except that PVA-2 was used instead of PVA-1 used in Example 1. The results are shown in Table 1.
PVA-2 was synthesized by the following method.
(Synthesis of PVA-2)
Into an autoclave having a capacity of 5 liters, 2238 g of vinyl acetate and 753 g of methanol were added and replaced with nitrogen, and then nitrogen in the system was replaced with ethylene. After replacing with ethylene, the internal temperature was adjusted to 60 ° C., and the pressure in the system was adjusted to 0.62 MPa by pressurizing with ethylene. After adjusting the pressure, 11.7 ml of a methanol solution of 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile) adjusted to a concentration of 0.5 g / liter as a polymerization initiator was fed to the autoclave. The polymerization was started. After the start of polymerization, the above-mentioned polymerization initiator solution was sequentially added at a rate of 37 ml / hour until the end of the polymerization. The polymerization was stopped when the solid content concentration in the system reached 29.3% 4 hours after the start of the polymerization. During this time, the pressure in the system was sequentially adjusted, and the pressure when the polymerization was stopped was 0.53 MPa. By passing methanol vapor through the obtained ethylene-vinyl acetate copolymer solution, the remaining vinyl acetate was completely removed, and an ethylene-vinyl acetate copolymer methanol solution with a solid content concentration of 30% was obtained. Obtained.
50 g of methanol was added to 333 g of the obtained ethylene-vinyl acetate copolymer methanol solution to adjust to 40 ° C., and then 16.3 g of 10% sodium hydroxide methanol solution was added to carry out a saponification reaction. One hour after adding the sodium hydroxide methanol solution after pulverizing the obtained gel-like substance, a large excess of methyl acetate was added to stop the saponification reaction, followed by washing with methanol and 1 at 65 ° C. By drying day and night, PVA-2 (polymerization degree 1000, saponification degree 99.2 mol%, ethylene content 7 mol%) was obtained.

Example 3
An aqueous resin dispersion and a water resistant composition were prepared and evaluated in the same manner as in Example 1 except that PVA-3 was used instead of PVA-1 used in Example 1. The results are shown in Table 1.
PVA-3 was synthesized by the following method.
(Synthesis of PVA-3)
An autoclave with a capacity of 5 liters was charged with 2850 g of vinyl acetate and 150 g of methanol and replaced with nitrogen, and then the internal temperature was adjusted to 120 ° C. and the pressure was adjusted to 0.45 MPa. Polymerization was initiated by feeding 3 ml of a methanol solution of 1,1′-azobis (cyclohexane-1-carbonitrile) adjusted to a concentration of 0.1% as a polymerization initiator to an autoclave. After the start of polymerization, the above-mentioned polymerization initiator solution was sequentially added at a rate of 12.7 ml / hour until the end of the polymerization. The polymerization was stopped when the solid content concentration in the system reached 14.14% 2.2 hours after the start of the polymerization. By passing methanol vapor through the vinyl acetate polymer solution, the remaining vinyl acetate was completely removed to obtain an ethylene-vinyl acetate copolymer methanol solution with a solid content concentration of 30%.
57 g of methanol was added to 333 g of the obtained ethylene-vinyl acetate copolymer methanol solution to adjust to 40 ° C., and then 9.3 g of 10% sodium hydroxide methanol solution was added to carry out a saponification reaction. One hour after adding the sodium hydroxide methanol solution after pulverizing the obtained gel-like substance, a large excess of methyl acetate was added to stop the saponification reaction, followed by washing with methanol and 1 at 65 ° C. By drying day and night, PVA-3 (polymerization degree 1700, saponification degree 98.5 mol%, 1,2-glycol bond amount 2.2 mol%) was obtained.

Example 4
In Example 1, PVA-4 (polymerization degree 1700, saponification degree 88 mol%: PVA-217 manufactured by Kuraray Co., Ltd.) was used instead of PVA-1, and acetoacetoxyethyl methacrylate added to the PVA aqueous solution was used. A water-based resin dispersion was prepared and evaluated in the same manner as in Example 1 except that the amount was changed from 25 g to 50 g. Further, a water-resistant composition was prepared and evaluated in the same manner as in Example 1 except that the amount of adipic acid dihydrazide added to the obtained aqueous resin dispersion was changed from 9.8 parts by weight to 16.3 parts by weight. did. The results are shown in Table 1.

Comparative Example 1
In Example 1, an aqueous resin dispersion and composition were prepared and evaluated in the same manner as in Example 1 except that acetoacetoxyethyl methacrylate was not used at all. The results are shown in Table 1.

Comparative Example 2
In Example 2, an aqueous resin dispersion and composition were prepared and evaluated in the same manner as in Example 2 except that acetoacetoxyethyl methacrylate was not used at all. The results are shown in Table 1.

Comparative Example 3
In Example 3, an aqueous resin dispersion and composition were prepared and evaluated in the same manner as in Example 3 except that acetoacetoxyethyl methacrylate was not used at all. The results are shown in Table 1.

Comparative Example 4
In Example 4, an aqueous resin dispersion and composition were prepared and evaluated in the same manner as in Example 4 except that no acetoacetoxyethyl methacrylate was used. The results are shown in Table 1.

Example 5
In Example 1, a water-resistant composition was prepared and evaluated in the same manner as in Example 1 except that 3.4 parts by weight of ethylenediamine was added as a water-resistant agent to the aqueous resin dispersion. The results are shown in Table 1.

Example 6
In Example 1, a water-resistant composition was prepared and evaluated in the same manner as in Example 1 except that 14.7 parts by weight of dihydroxytitanium bislactate was added as a water-resistant agent to the aqueous resin dispersion. The results are shown in Table 1.

Comparative Example 5
A water-based resin dispersion was prepared and evaluated in the same manner as in Example 1 except that the amount of acetoacetoxyethyl methacrylate used was changed from 25 g to 250 g. Further, a composition was prepared and evaluated in the same manner as in Example 1 except that the amount of adipic acid dihydrazide added to the obtained aqueous resin dispersion was changed from 9.8 parts by weight to 98 parts by weight. The results are shown in Table 1.

Comparative Example 6
A glass polymerization vessel having a capacity of 2 liters equipped with a reflux condenser, a thermometer, and a nitrogen inlet is charged with 900 g of ion-exchanged water and 1 g of nonionic emulsifier (Nonion K-220 manufactured by Nippon Oil & Fats Co., Ltd.). After replacing this aqueous solution with nitrogen, the temperature was adjusted to 60 ° C. while stirring at 130 rpm, and 100 g of acetoacetoxyethyl methacrylate and 5 g of a 10% aqueous solution of sodium tartrate were charged. Thereafter, 50 g of 0.5% aqueous hydrogen peroxide was continuously added dropwise over 3 hours to carry out emulsion polymerization. After 3 hours, a polyacetoacetoxyethyl methacrylate dispersion having a solid content of 9.94% (polymerization rate of acetoacetoxyethyl methacrylate of 99.7%) was obtained. 25.15 g of this dispersion was added to 100 g of a 10% aqueous solution of PVA-1 separately prepared by dissolving PVA to obtain a mixed dispersion of polyacetoacetoxyethyl methacrylate and PVA.
A composition was prepared by adding 9.8 parts by weight of adipic acid dihydrazide as a waterproofing agent to 100 parts by weight of the solid content of the obtained mixed dispersion.
The mixed dispersion and composition were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 7
With reference to Example 1 described in JP-A-9-124874, the reaction between PVA and diketene was carried out, and acetoacetyl group-containing PVA (PVA-5: saponification degree 99.4 mol%, polymerization degree 1200, aceto The degree of acetylation was 6.0 mol%). The obtained PVA-5 was dissolved by heating to prepare a 10% aqueous solution.
A composition was prepared by adding 11.8 parts by weight of adipic acid dihydrazide as a waterproofing agent to 100 parts by weight of the solid content of the obtained aqueous solution.
The aqueous solution and composition were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 7
In Example 1, instead of using 25 g of acetoacetoxy methacrylate, an aqueous resin dispersion was prepared in the same manner as in Example 1 except that 10 g of acetoacetoxy methacrylate and 40 g of methyl methacrylate were used. A water resistant composition was prepared in the same manner as in Example 1 except that the amount of adipic acid dihydrazide added to the dispersion was changed from 9.8 parts by weight to 3.2 parts by weight. Table 1 shows the results of the evaluation of the aqueous resin dispersion and the water-resistant composition.

Comparative Example 8
In Example 1, instead of using 25 g of acetoacetoxy methacrylate, an aqueous resin dispersion was prepared in the same manner as in Example 1 except that 2 g of acetoacetoxy methacrylate and 48 g of methyl methacrylate were used. A composition was prepared in the same manner as in Example 1 except that the amount of adipic acid dihydrazide added to the dispersion was changed from 9.8 parts by weight to 3.2 parts by weight. The results of evaluating the aqueous resin dispersion and composition are shown in Table 1.

  By comparing the results of Examples 1 to 4 with the results of Comparative Examples 1 to 4, by blending the aqueous resin satisfying claim 1 or an aqueous dispersion thereof (a) and a water-resistant agent (b), It can be seen that a water-resistant composition excellent in storage stability, water resistance of the film, and transparency of the film can be obtained. When the weight ratio (A) / (B) of the polymer (A) composed of a vinyl monomer unit having an acetoacetyl group and the vinyl alcohol polymer (B) exceeds 200/100, the water-resistant composition is stored. Stability and transparency of the film are reduced (Comparative Example 5). When the weight ratio of (A) bound to (B) is less than 50% with respect to the total weight of (A), the storage stability of the water-resistant composition, the water resistance of the film, and the transparency of the film (Comparative Example 6). In addition, the water-resistant composition of the present invention is remarkably superior in storage stability as compared with a composition (Comparative Example 7) containing an acetoacetyl group-containing PVA obtained by a conventionally known reaction between PVA and diketene. ing. The water-resistant composition (Example 7) comprising as a component a polymer (A) containing 5% by weight or more of vinyl monomer units having an acetoacetyl group has a content of vinyl monomer units having an acetoacetyl group of 5 Compared to a water resistant composition (Comparative Example 8) containing a polymer of less than% by weight as a component, the film is remarkably excellent in water resistance.

The water-resistant composition of the present invention has excellent storage stability, and even a film obtained by drying at room temperature is excellent in water resistance and transparency. It is suitably used for thermal paper overcoat agents that cannot be applied. Further, the water-resistant composition of the present invention comprises an inorganic or organic adhesive such as an adhesive for secondary processing of plywood, a binder for ceramics, a dispersant for dispersing a pigment, a polymerization stabilizer for a crosslinkable emulsion, a gelatin blend or It can also be used effectively for image forming materials such as photosensitive resins, base materials for hydrogels such as bacterial cell-fixed gels or enzyme-fixed gels, paint vehicles, treatment agents for inorganic materials or organic materials, such as surface coating agents. In addition, it can be used in a wide range of applications where water-soluble resins have been conventionally used. Furthermore, the water-resistant composition of the present invention can be processed into a molded product such as a film, a sheet, or a fiber.

Claims (5)

  It consists of a polymer (A) containing at least 5% by weight of a vinyl monomer unit having an acetoacetyl group and a vinyl alcohol polymer (B), and the weight ratio (A) / (B) is 2/100 to 200/100. A water-resistant agent (b) is blended with an aqueous resin or an aqueous dispersion (a) in which the weight ratio of (A) bound to (B) is 50% or more with respect to the total weight of (A). Water resistant composition.   The vinyl alcohol polymer (B) is a vinyl alcohol polymer containing 1 to 20 mol% of α-olefin units having 4 or less carbon atoms in the molecule and having a saponification degree of 80 mol% or more. Water resistant composition.   The water-resistant composition according to claim 2, wherein the α-olefin unit is an ethylene unit.   The water-resistant composition according to claim 1, wherein the vinyl alcohol polymer (B) is a vinyl alcohol polymer having a 1,2-glycol bond amount of 1.9 mol% or more and a saponification degree of 80 mol% or more. object. The water-resistant composition according to any one of claims 1 to 4, wherein the water-resistant agent (b) is at least one water-resistant agent selected from a hydrazide compound, an amine compound, and a polyvalent metal compound.