JP2014118540A - Aqueous emulsion composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aqueous emulsion composition containing a vinylalcohol-based polymer capable of exhibiting excellent emulsion polymerization stability when used as a polymerization stabilizer, balancing water resistance and viscosity shelf stability of a coating film of the obtained emulsion, and balancing water resistance and viscosity shelf stability of the coating film even when used as a post addition treatment agent after emulsion polymerization.SOLUTION: An aqueous emulsion composition contains a vinylalcohol polymer containing a monomer unit having a group represented by the formula (1) and satisfying the formula (I), and a vinyl-based polymer. It is preferable that the vinylalcohol polymer satisfies further formulae (II) and (III). 370≤P×S≤6,000 (I). 200≤P≤4,000 (II). 0.1≤S≤10 (III). where P:a viscosity-average polymerization degree, S:a percentage content of the monomer unit (mol%).

Description

  The present invention relates to an aqueous emulsion composition.

  A vinyl alcohol polymer represented by polyvinyl alcohol (hereinafter sometimes abbreviated as “PVA”) is known as a water-soluble synthetic polymer, and is a raw material for vinylon which is a synthetic fiber, a paper processing agent. It is widely used for applications such as fiber processing agents, adhesives, stabilizers for emulsion polymerization and suspension polymerization, inorganic binders and films. In particular, PVA is known as a protective colloid for emulsion polymerization of vinyl ester monomers typified by vinyl acetate. Using this as a stabilizer for emulsion polymerization, an aqueous vinyl ester emulsion obtained by emulsion polymerization, Alternatively, this PVA is used as a post-treatment agent after emulsion polymerization, and a vinyl ester aqueous emulsion obtained by post-addition to a base vinyl ester emulsion is used for various adhesives for paper, woodwork, plastics, and impregnated paper. Widely used in the fields of various binders, admixtures, jointing materials, paints, paper processing, fiber processing, etc. for use and non-woven products.

  When such PVA is used as a stabilizer for emulsion polymerization, it is required to exhibit polymerization stability that suppresses aggregation of the emulsion during emulsion polymerization. Further, when such PVA is used as a stabilizer for emulsion polymerization or a post-treatment agent after emulsion polymerization, PVA is water-soluble, so that the water resistance of the emulsion film obtained by emulsion polymerization is lowered. Furthermore, in the case where such PVA is used as a stabilizer for emulsion polymerization or a post-treatment agent after emulsion polymerization, the resulting emulsion has little change in viscosity with standing, that is, it has excellent viscosity standing stability. It is requested.

  As PVA excellent in water resistance of a film obtained from a PVA aqueous solution, the product (P × S) of the viscosity average polymerization degree (P) and the content of monomer units having a silyl group (S: mol%) is 20 < A silyl group-containing PVA in which P × S <370 has been proposed (see JP-A-2004-43644). However, when such silyl group-containing PVA is used as a stabilizer for emulsion polymerization or a post-addition treatment agent after emulsion polymerization, the resulting aqueous emulsion composition may lack water resistance for use as various adhesives. .

JP 2004-43644 A

  The present invention has been made based on the circumstances as described above, and can exhibit excellent emulsion polymerization stability when used as a stabilizer for emulsion polymerization. A vinyl alcohol polymer that can achieve both standing stability and can achieve both water resistance and viscosity standing stability of the resulting emulsion film even when used as a post-treatment agent after emulsion polymerization. It is an object to provide an aqueous emulsion composition containing

（式（１）中、Ｒ^１は、水素原子又は炭素数１〜５のアルキル基である。Ｒ^２は、アルコキシル基、アシロキシル基又はＯＭで表される基である。Ｍは、水素原子、アルカリ金属又はアンモニウム基である。Ｒ^３及びＲ^４は、それぞれ独立して、水素原子又はアルキル基である。Ｒ^１〜Ｒ^４で表されるアルキル基、アルコキシル基及びアシロキシル基が有する水素原子は、酸素原子又は窒素原子を含有する置換基で置換されていてもよい。ｍは、０〜２の整数である。ｎは、３以上の整数である。Ｒ^１〜Ｒ^４がそれぞれ複数存在する場合、複数存在する各Ｒ^１〜Ｒ^４は、独立して上記定義を満たす。）
３７０≦Ｐ×Ｓ≦６，０００ ・・・（Ｉ）
Ｐ：粘度平均重合度
Ｓ：上記単量体単位の含有率（モル％） The invention made to solve the above problems is
A vinyl alcohol polymer containing a monomer unit having a group represented by the following formula (1) and satisfying the following formula (I), and an aqueous emulsion composition containing the vinyl polymer.

(In Formula (1), R ¹ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. R ² is an alkoxyl group, an acyloxyl group, or a group represented by OM. M is a hydrogen atom, R ³ and R ⁴ are each independently a hydrogen atom or an alkyl group, each of which represents an alkyl group, an alkoxyl group or an acyloxyl group represented by R ^{1 to} R ^4. May be substituted with a substituent containing an oxygen atom or a nitrogen atom, m is an integer of 0 to 2. n is an integer of 3 or more, and there are a plurality of R ^{1 to} R ⁴ , respectively. In the case, a plurality of each R ^{1 to} R ⁴ independently satisfy the above definition.)
370 ≦ P × S ≦ 6,000 (I)
P: Viscosity average degree of polymerization S: Content of the monomer unit (mol%)

  The PVA contained in the aqueous emulsion composition includes a monomer unit having a group represented by the above formula (1), and a structure in which a silyl group is connected to a main chain via an alkylene group having 3 or more carbon atoms. have. For this reason, even if the amount of modification of the silyl group of the PVA is increased, the aqueous emulsion composition has high water solubility in the neutral region, so that it is excellent in handleability, high in viscosity stability, and high in emulsion polymerization stability. Become. According to the aqueous emulsion composition, since the product (P × S) of the viscosity average polymerization degree (P) of the contained PVA and the content (S) of the monomer unit is in the above range, the silyl group modification The amount can be increased, emulsion polymerization stability can be improved, and an emulsion having excellent water resistance and viscosity standing stability can be obtained.

The PVA preferably further satisfies the following formulas (II) and (III).
200 ≦ P ≦ 4,000 (II)
0.1 ≦ S ≦ 10 (III)
P: Viscosity average degree of polymerization S: Content of the monomer unit (mol%)

  Thus, the PVA contained in the aqueous emulsion composition is used as a stabilizer for emulsion polymerization by setting the viscosity average polymerization degree (P) of the PVA and the content (S) of the monomer units in the above ranges. In this case, it is possible to exhibit better emulsion polymerization stability. When such PVA is used as a stabilizer for emulsion polymerization or a post-addition treatment agent after emulsion polymerization, the water resistance and the viscosity standing stability of the resulting emulsion film are both obtained. Can be further improved.

  In the above formula (1), n is preferably an integer of 6 to 20. By setting the value of n within the above range, various performances of the aqueous emulsion composition can be further enhanced.

（式（２）中、Ｒ^１〜Ｒ^４、ｍ及びｎは、式（１）と同義である。Ｘは、直接結合、２価の炭化水素基又は酸素原子若しくは窒素原子を含む２価の有機基である。Ｒ^５は、水素原子又はメチル基である。） The monomer unit is preferably represented by the following formula (2).

(In the formula (2), R ^{1 to} R ⁴ , m and n have the same meanings as in the formula (1). X is a direct bond, a divalent hydrocarbon group, a divalent hydrocarbon group containing an oxygen atom or a nitrogen atom. (It is an organic group. R ⁵ is a hydrogen atom or a methyl group.)

  When the monomer unit has a structure represented by the formula (2), various performances of the aqueous emulsion composition can be further enhanced.

X in the above formula (2) is preferably represented by the following formula (3).
-CO-NR ^6- * (3)
(In the formula (3), R ⁶ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. * Indicates a bonding position with the group represented by the above formula (1).)

  Thus, the various performances of the aqueous emulsion composition can be further improved by having the amide structure at a position where the monomer unit is separated from the silyl group.

R ⁶ in the above formula (3) is a hydrogen atom, and n in the above formula (2) is preferably an integer of 3 to 12. By setting the monomer unit to such a structure, various performances of the aqueous emulsion composition can be effectively enhanced, and the production of the PVA can be easily performed.

  The aqueous emulsion composition of the present invention is produced by polymerizing a vinyl monomer using the vinyl alcohol polymer as a stabilizer for emulsion polymerization.

  The aqueous emulsion composition of the present invention can also be produced by adding the vinyl alcohol polymer to an aqueous emulsion containing a vinyl polymer.

  As described above, the aqueous emulsion composition of the present invention contains PVA capable of exhibiting excellent emulsion polymerization stability when used as a stabilizer for emulsion polymerization. The aqueous emulsion composition of the present invention containing specific PVA as a stabilizer for emulsion polymerization or a post-addition treatment agent after emulsion polymerization achieves both the water resistance of the resulting emulsion film and the viscosity standing stability. be able to. Therefore, the aqueous emulsion composition is suitably used for various adhesives for paper, woodwork, plastics and the like.

  Hereinafter, embodiments of the aqueous emulsion composition of the present invention will be described in detail.

<Aqueous emulsion composition>
The aqueous emulsion composition of the present invention contains PVA and a vinyl polymer detailed below.

<PVA>
The PVA includes a monomer unit having a group represented by the formula (1). That is, the PVA is a copolymer containing a monomer unit having a group represented by the formula (1) and a vinyl alcohol unit (—CH ₂ —CHOH—), and further another monomer unit. You may have.

In the above formula (1), ^{R 1} is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, and a propyl group.

R ² is a group represented by an alkoxyl group, an acyloxyl group, or OM. M is a hydrogen atom, an alkali metal, or an ammonium group ( ⁺ NH ₄ ). Examples of the alkoxyl group include a methoxy group and an ethoxy group. Examples of the acyloxyl group include an acetoxy group and a propionyloxy group. Examples of the alkali metal include sodium and potassium. Among these groups represented by R ² , an alkoxyl group or a group represented by OM is preferable, an alkoxyl group having 1 to 5 carbon atoms, and a group represented by OM in which M is a hydrogen atom or an alkali metal. More preferably, a methoxy group, an ethoxy group, and a group represented by OM in which M is sodium or potassium are more preferable.

R ³ and R ⁴ are each independently a hydrogen atom or an alkyl group. Examples of the alkyl group include the above-described alkyl groups having 1 to 5 carbon atoms. R ³ and R ⁴ are preferably a hydrogen atom or a methyl group.

The hydrogen atom which the alkyl group, alkoxyl group, and acyloxyl group represented by R ^{1 to} R ⁴ have may be substituted with a substituent containing an oxygen atom or a nitrogen atom. Examples of the substituent containing an oxygen atom include an alkoxyl group and an acyloxyl group. In addition, examples of the substituent containing a nitrogen atom include an amino group and a cyano group.

In ^the case where R 1 to R ⁴ is present in plural, each ^R 1 to R ⁴ that there are two or more, independently meets the above definition. Here, “independently satisfy the above definition” means that the above definition may be the same or different.

m is an integer of 0 to 2, and 0 is preferable. When m is 0, that is, the monomer unit has three R ² groups, the effect of modification can be further enhanced.

n is an integer of 3 or more. The upper limit of n is not particularly limited, but 20 is preferable, 15 is more preferable, and 12 is more preferable. As a lower limit of n, 4 is preferable, 6 is more preferable, and 8 is more preferable. The PVA has a structure in which n in the formula (1) is 3 or more, that is, the silyl group is connected to the main chain via an alkylene group having 3 or more carbon atoms, so that the amount of modification of the silyl group can be reduced. Even if it raises, the fall of water solubility etc. is suppressed. The reason why such an effect is not fully elucidated has been elucidated, but for example, an alkylene group having 3 or more carbon atoms exhibiting hydrophobicity reduces the hydrolysis rate of Si—R ² in an aqueous solution, thereby causing a reaction. It is presumed to be for inhibiting.

  The specific structure of the monomer unit is not particularly limited as long as it has a group represented by the above formula (1), but is preferably represented by the above formula (2).

Wherein ^(2), R 1 ^{to R} 4, m and n are as defined for formula (1). The same applies to these preferred groups or numerical ranges.

  X is a direct bond, a divalent hydrocarbon group, or a divalent organic group containing an oxygen atom or a nitrogen atom. When the monomer unit has a structure represented by the formula (2), various performances of the aqueous emulsion composition can be further enhanced.

  Examples of the divalent hydrocarbon group include a divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms and a divalent aromatic hydrocarbon group having 6 to 10 carbon atoms. Examples of the aliphatic hydrocarbon group having 1 to 10 carbon atoms include a methylene group, an ethylene group, and a propylene group. A phenylene group etc. are mentioned as said C6-C10 bivalent aromatic hydrocarbon group. Examples of the divalent organic group containing an oxygen atom include ether groups, ester groups, carbonyl groups, amide groups, and groups in which these groups are connected to a divalent hydrocarbon group. Examples of the divalent organic group containing a nitrogen atom include an imino group, an amide group, and a group in which these groups are connected to a divalent hydrocarbon group.

X in the formula (2) is preferably a divalent organic group containing an oxygen atom or a nitrogen atom, more preferably a group containing an amide group, and even more preferably a group represented by the formula (3). . Thus, when the monomer unit has a polar structure, preferably an amide structure, at a position away from the silyl group, water solubility and the like can be further improved while maintaining the performance derived from the silyl group. In addition, as R < ⁶ > in the said Formula (3), a hydrogen atom is preferable from the point which can raise the said function more or can manufacture the said PVA easily.

R ⁵ is a hydrogen atom or a methyl group.

  As said monomer unit, what is represented by following formula (4) is still more preferable.

In the formula (4), R ¹ , R ² , R ⁵ , X and m are as defined in the above formula (2). The same applies to these preferred groups or numerical ranges.

In the above formula (4), R ³ ′ and R ⁴ ′ are each independently a hydrogen atom or an alkyl group. As this alkyl group, the C1-C5 alkyl group mentioned above is mentioned. R ³ ′ and R ⁴ ′ are preferably a hydrogen atom or a methyl group, and more preferably a hydrogen atom. The hydrogen atom contained in the alkyl group represented by R ³ ′ and R ⁴ ′ may be substituted with a substituent containing an oxygen atom or a nitrogen atom. Examples of the substituent containing an oxygen atom include an alkoxyl group and an acyloxyl group. In addition, examples of the substituent containing a nitrogen atom include an amino group and a cyano group. When there are a plurality of R ³ ′ and R ⁴ ′, a plurality of R ³ ′ and R ⁴ ′ satisfy the above definition independently.

  In the above formula (4), n ′ is an integer of 1 or more. The upper limit of n 'is not particularly limited, but 18 is preferable, 13 is more preferable, and 10 is more preferable. As a lower limit of n ′, 2 is preferable, 4 is more preferable, and 6 is more preferable.

When the monomer unit is represented by the above formula (4), various functions of the aqueous emulsion composition can be expressed more effectively. The reason for this is not clear, but it is presumed that the above-described function of reducing the hydrolysis rate of Si—R ² and inhibiting the reaction in the aqueous solution is more effectively exhibited.

The PVA satisfies the following formula (I).
370 ≦ P × S ≦ 6,000 (I)
P: Viscosity average degree of polymerization S: Content of the monomer unit (mol%)

The viscosity average degree of polymerization (P) is measured according to JIS-K6726. That is, when the saponification degree of the PVA is less than 99.5 mol%, the saponification degree is re-saponified to 99.5 mol% or more, and after purification, the intrinsic viscosity [η] measured in water at 30 ° C. (unit: (Deciliter / g) can be obtained by the following equation.
P = ([η] × 1000 / 8.29) ^{(1 / 0.62)}

The content of the monomer unit (S: mol%) can be obtained from proton NMR of the vinyl ester polymer before saponification. Here, when the proton NMR of the vinyl ester polymer before saponification is measured, the vinyl ester polymer is purified by reprecipitation with hexane-acetone, and the monomer having an unreacted silyl group is contained in the polymer. The body is sufficiently removed and then dried at 90 ° C. under reduced pressure for 2 days, and then dissolved in CDCl ₃ solvent for analysis.

The product (P × S) of the viscosity average degree of polymerization (P) and the content (S) of the monomer units corresponds to the number (average value) of the monomer units per 100 molecules. When this product (P × S) is less than the above lower limit, the water resistance of the resulting emulsion film may be insufficient. Conversely, if this product (P × S) exceeds the above upper limit, the water solubility of the PVA, the viscosity standing stability of the resulting emulsion, and the like may decrease. The product (P × S) preferably satisfies the following formula (I ′), and more preferably satisfies the following formula (I ″).
400 ≦ P × S ≦ 3,000 (I ′)
500 ≦ P × S ≦ 2,000 (I ″)

The PVA preferably further satisfies the following formulas (II) and (III).
200 ≦ P ≦ 4,000 (II)
0.1 ≦ S ≦ 10 (III)
P: Viscosity average degree of polymerization S: Content of the monomer unit (mol%)

  Thus, by setting the viscosity average degree of polymerization (P) and the content of the monomer units (S) in the above ranges, the emulsion polymerization stability is further improved when the PVA is used as a stabilizer for emulsion polymerization. When the PVA is used as a stabilizer for emulsion polymerization or a post-addition treatment agent after emulsion polymerization, the water resistance and viscosity standing stability of the resulting emulsion film can be further improved.

Furthermore, in the viscosity average polymerization degree (P), it is more preferable to satisfy the following formula (II ′), and it is more preferable to satisfy the following formula (II ″).
500 ≦ P ≦ 3,000 (II ′)
1,000 ≦ P ≦ 2,400 (II ″)

  When the viscosity average degree of polymerization (P) is less than the above lower limit, the water resistance of the resulting emulsion film may be lowered. Conversely, when the viscosity average degree of polymerization (P) exceeds the above upper limit, the emulsion polymerization stability and water solubility of the PVA, and the viscosity standing stability of the resulting aqueous emulsion composition may decrease.

Moreover, in the content rate of the said monomer unit, it is more preferable to satisfy | fill following formula (III '), and it is still more preferable to satisfy | fill following formula (III'').
0.25 ≦ S ≦ 6 (III ′)
0.5 ≦ S ≦ 5 (III ″)

  When the content rate (S) of the monomer unit is less than the lower limit, the water resistance and the like of the resulting emulsion film may be lowered. On the other hand, when the content (S) of the monomer unit exceeds the upper limit, the emulsion polymerization stability, water solubility, and viscosity standing stability of the resulting aqueous emulsion composition may be reduced. is there.

  Although there is no restriction | limiting in particular as the saponification degree of the said PVA, 80 mol% or more is preferable, 90 mol% or more is more preferable, 95 mol% or more is more preferable, 97 mol% or more is especially preferable. When the degree of saponification of the PVA is less than the above lower limit, the water resistance of the resulting emulsion film may be lowered. The upper limit of the saponification degree of the PVA is not particularly limited, but is 99.9 mol%, for example, in consideration of productivity. Here, the degree of saponification of PVA refers to a value measured according to the method described in JIS-K6726.

<Method for producing PVA>
Although it does not specifically limit as a manufacturing method of the said PVA, For example, a copolymer obtained by copolymerizing a vinyl ester monomer and the monomer which has group represented by the said Formula (1) ( It can be obtained by saponifying a vinyl ester polymer).

  Examples of the vinyl ester monomers include vinyl formate, vinyl acetate, vinyl propionate, vinyl valelate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl benzoate, vinyl pivalate, vinyl versatate and the like. Can be mentioned. Among these, vinyl acetate is preferable.

  In addition, for the purpose of adjusting the viscosity average polymerization degree (P) of the obtained PVA at the time of copolymerization of the monomer having a group represented by the above formula (1) and a vinyl ester monomer, Polymerization may be carried out in the presence of a chain transfer agent as long as the gist of the present invention is not impaired. Examples of the chain transfer agent include aldehydes such as acetaldehyde and propionaldehyde; ketones such as acetone and methyl ethyl ketone; 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-hydroxyethanethiol, n-dodecanethiol, Mercaptans such as mercaptoacetic acid and 3-mercaptopropionic acid; and halogenated hydrocarbons such as tetrachloromethane, bromotrichloromethane, trichloroethylene and perchloroethylene.

  As a monomer which has group represented by the said Formula (1), the compound represented, for example by following formula (5) is mentioned. By using a compound represented by the following formula (5), finally, a PVA containing a monomer unit having a group represented by the above formula (2) can be easily obtained.

In formula (5), R ^{1 to} R ⁵ , X, m, and n are as defined in formula (2). The same applies to these preferred groups or numerical ranges.

  Examples of the compound represented by the above formula (5) include 3- (meth) acrylamidopropyltrimethoxysilane, 4- (meth) acrylamidobutyltrimethoxysilane, 6- (meth) acrylamidehexyltrimethoxysilane, 8- ( (Meth) acrylamide octyltrimethoxysilane, 12- (meth) acrylamide dodecyltrimethoxysilane, 18- (meth) acrylamide octadecyltrimethoxysilane, 3- (meth) acrylamidepropyltriethoxysilane, 3- (meth) acrylamidepropyltributoxy Silane, 3- (meth) acrylamidopropylmethyldimethoxysilane, 3- (meth) acrylamidopropyldimethylmethoxysilane, 3- (meth) acrylamide-3-methylbutyltrimethoxysilane, 4- (Meth) acrylamide-4-methylbutyltrimethoxysilane, 4- (meth) acrylamide-3-methylbutyltrimethoxysilane, 5- (meth) acrylamide-5-methylhexyltrimethoxysilane, 4-pentenyltrimethoxysilane, 5 -Hexenyltrimethoxysilane and the like.

  Examples of the method for copolymerizing the vinyl ester monomer and the monomer having the group represented by the formula (1) include a bulk polymerization method, a solution polymerization method, a suspension polymerization method, and an emulsion polymerization method. A well-known method is mentioned. In particular, when the polymerization temperature is lower than 30 ° C., an emulsion polymerization method is preferable, and when the polymerization temperature is 30 ° C. or higher, a bulk polymerization method performed without solvent or a solution polymerization method performed using a solvent such as alcohol is used. Usually adopted.

  In the case of the emulsion polymerization method, examples of the solvent include water, and lower alcohols such as methanol and ethanol may be used in combination. Moreover, a well-known emulsifier can be used as an emulsifier. As an initiator for copolymerization, a redox initiator using iron ions, an oxidizing agent and a reducing agent in combination is preferably used for controlling the polymerization. In the case of the bulk polymerization method or the solution polymerization method, the reaction can be carried out by either a batch method or a continuous method in carrying out the copolymerization reaction. When the copolymerization reaction is carried out using the solution polymerization method, examples of the alcohol used as the solvent include lower alcohols such as methanol, ethanol, and propanol. Examples of the initiator used for the copolymerization reaction in this case include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), 1,1′-azobis ( Azo initiators such as cyclohexane-1-carbonitrile) and 2,2′-azobis (N-butyl-2-methylpropionamide); peroxide initiators such as benzoyl peroxide and n-propyl peroxycarbonate And known initiators. Although there is no restriction | limiting in particular about the polymerization temperature at the time of performing a copolymerization reaction, The range of 5 to 50 degreeC is suitable.

  In the case of this copolymerization reaction, a copolymerizable monomer can be copolymerized as necessary as long as the gist of the present invention is not impaired. Examples of such a monomer include α-olefins such as ethylene, propylene, 1-butene, isobutene, and 1-hexene; carboxylic acids such as fumaric acid, maleic acid, itaconic acid, maleic anhydride, and itaconic anhydride; Derivatives thereof; acrylic acid or salts thereof, acrylic acid esters such as methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate; methacrylic acid or salts thereof, methyl methacrylate, ethyl methacrylate, n methacrylate -Methacrylic acid esters such as propyl and isopropyl methacrylate; Acrylamide derivatives such as acrylamide, N-methylacrylamide and N-ethylacrylamide; Methacrylamide derivatives such as methacrylamide, N-methylmethacrylamide and N-ethylmethacrylamide; Vinyl ethers such as til vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether; hydroxy group-containing vinyl ethers such as ethylene glycol vinyl ether, 1,3-propanediol vinyl ether, 1,4-butanediol vinyl ether; Allyl ethers; allyl ethers such as propyl allyl ether, butyl allyl ether, hexyl allyl ether; monomers having an oxyalkylene group; isopropenyl acetate; 3-buten-1-ol, 4-penten-1-ol, 5 -Hydroxyl-containing α-olefins such as hexen-1-ol, 7-octen-1-ol, 9-decen-1-ol, 3-methyl-3-buten-1-ol; vinyl sulfone , Monomers having a sulfonic acid group such as allylsulfonic acid, methallylsulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid; vinyloxyethyltrimethylammonium chloride, vinyloxybutyltrimethylammonium chloride, vinyloxyethyldimethylamine , Having a cationic group such as vinyloxymethyldiethylamine, N-acrylamidomethyltrimethylammonium chloride, N-acrylamidoethyltrimethylammonium chloride, N-acrylamidodimethylamine, allyltrimethylammonium chloride, methallyltrimethylammonium chloride, dimethylallylamine, allylethylamine And monomers. The amount of these monomers used varies depending on the purpose and application of use, but is usually 20 mol% or less based on all monomers used for copolymerization, % Or less is preferable.

  The vinyl ester polymer obtained by the copolymerization is then saponified in a solvent according to a known method and led to PVA.

  As the catalyst for the saponification reaction, an alkaline substance is usually used, and examples thereof include alkali metal hydroxides such as potassium hydroxide and sodium hydroxide, and alkali metal alkoxides such as sodium methoxide. The amount of the alkaline substance used is preferably in the range of 0.004 to 0.5 in terms of a molar ratio based on the vinyl ester monomer unit in the vinyl ester polymer. More preferably, it is in the range of 0.05. Further, this catalyst may be added all at once in the early stage of the saponification reaction, or a part thereof may be added in the early stage of the saponification reaction, and the rest may be added in the middle of the saponification reaction.

  Examples of the solvent that can be used for the saponification reaction include methanol, methyl acetate, dimethyl sulfoxide, diethyl sulfoxide, dimethylformamide, and the like. Of these solvents, methanol is preferred. Further, in the use of methanol, the water content in methanol is preferably adjusted to 0.001 to 1% by mass, more preferably 0.003 to 0.9% by mass, and particularly preferably 0.005 to 0.8% by mass. It is good to be.

  The saponification reaction is preferably performed at a temperature of 5 ° C to 80 ° C, more preferably 20 ° C to 70 ° C. The time required for the saponification reaction is preferably 5 minutes to 10 hours, more preferably 10 minutes to 5 hours. The saponification reaction can be carried out by either a batch method or a continuous method. After completion of the saponification reaction, the remaining saponification catalyst may be neutralized as necessary, and usable neutralizing agents include organic acids such as acetic acid and lactic acid, and ester compounds such as methyl acetate. .

  The PVA obtained by the saponification reaction can be washed as necessary. Examples of the cleaning liquid used in this cleaning include lower alcohols such as methanol, lower fatty acid esters such as methyl acetate, and mixtures thereof. A small amount of water, alkali, acid, or the like may be added to these cleaning liquids.

  The method for emulsion polymerization of the monomer using the PVA contained in the aqueous emulsion composition is not particularly limited. For example, the monomer is used in the presence of a conventionally known polymerization initiator using the PVA. Is added temporarily or continuously. Although it does not restrict | limit especially as the usage-amount of said PVA, It is 1-25 mass parts normally with respect to 100 mass parts of polymers of the ethylenically unsaturated monomer illustrated as a dispersoid mentioned later, and 2-15 mass parts Is preferred. In addition to the PVA, the aqueous emulsion composition may contain other components such as a conventionally known anionic, nonionic, and cationic surfactant, non-modified PVA, and hydroxyethyl cellulose, as long as the above-described effects are not impaired. Etc. may be contained.

<Aqueous emulsion composition>
The aqueous emulsion composition of the present invention contains the PVA and vinyl polymer described above. Therefore, the water-based emulsion composition can achieve both the water resistance of the resulting emulsion film and the viscosity standing stability. The aqueous emulsion composition includes the PVA, a vinyl polymer such as a dispersoid composed of a polymer formed by emulsion polymerization, and a dispersion medium such as water. The aqueous emulsion composition can also be obtained by emulsion polymerization of a vinyl polymer using the above-mentioned PVA as a stabilizer for emulsion polymerization, or base vinyl obtained by emulsion polymerization of a vinyl polymer. It can also be obtained by adding the PVA as an after-treatment agent to the ester emulsion. The amount of PVA added as a post-treatment agent is not particularly limited, but the PVA solid content is 1 to 20% by mass with respect to 100% by mass of the base vinyl ester emulsion solid content. It is preferable to add. The aqueous emulsion composition may be an emulsion itself obtained by emulsion polymerization, and may contain a crosslinking agent, a filler, a plasticizer and the like.

<Vinyl polymer (dispersoid)>
Examples of the polymer constituting the dispersoid of the aqueous emulsion composition include polymers derived from ethylenically unsaturated monomers and diene monomers. Examples of the ethylenically unsaturated monomer include olefins such as ethylene, propylene, and isobutylene; halogenated olefins such as vinyl chloride, vinyl fluoride, vinylidene chloride, and vinylidene fluoride; vinyl formate, vinyl acetate, vinyl propionate, Vinyl esters such as vinyl vinyl versatate; acrylic acid esters such as acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, 2-hydroxyethyl acrylate; methacrylic acid Methacrylic acid esters such as methyl, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, dodecyl methacrylate, 2-hydroxyethyl methacrylate; dimethylaminoethyl acrylate, methacrylic acid Acrylamide monomers such as dimethylaminoethyl and quaternized compounds thereof, acrylamide, methacrylamide, N-methylolacrylamide, N, N-dimethylacrylamide, acrylamide-2-methylpropanesulfonic acid and its sodium salt; styrene, α -Styrene monomers such as methyl styrene, p-styrene sulfonic acid and its sodium salt, potassium salt; N-vinyl pyrrolidone and the like. Examples of the diene monomer include butadiene, isoprene, chloroprene and the like. These monomers may be used alone or in combination of two or more.

  Of the above monomers, vinyl esters, methacrylic acid esters, styrene monomers, and diene monomers are preferable, vinyl esters and methacrylic acid esters are more preferable, and vinyl acetate is more preferable.

(Crosslinking agent)
The aqueous emulsion composition may contain a crosslinking agent. When the aqueous emulsion composition contains a crosslinking agent, the water resistance and water-resistant adhesive strength of the film obtained from the aqueous emulsion composition can be further increased.

  Examples of the crosslinking agent include aldehyde compounds such as glyoxal and glutaraldehyde, zirconium compounds such as ammonium zirconium carbonate, titanium compounds such as titanium lactate, epoxy compounds such as polyamidoamine epichlorohydrin, colloidal silica, tetramethoxysilane, and 3-glycidide. Examples thereof include silicon-containing compounds such as xylpropyltrimethoxysilane, 3-aminopropyltrimethoxysilane and oligomers which are hydrolysis condensates thereof, polyoxazoline, urea resin, melamine resin, and polyvalent metal salt.

  The crosslinking agent preferably contains at least one compound (B) selected from the group consisting of a silicon-containing compound, a titanium compound, and a zirconium compound. When the crosslinking agent contains the compound (B), the water resistance and water-resistant adhesive strength of the film obtained from the aqueous emulsion composition can be effectively increased. The content of the compound (B) is preferably 0.01 parts by mass or more and 900 parts by mass or less with respect to 100 parts by mass of the emulsion polymerization stabilizer.

(filler)
The aqueous emulsion composition may further contain an organic or inorganic filler (filler). When the aqueous emulsion composition further contains the filler, the water resistance, water-resistant adhesive strength, and the like of the resulting film are improved. Examples of the filler (filler) include clay, kaolin, talc, calcium carbonate, wood flour, wheat flour, and titanium oxide.

(Plasticizer)
The aqueous emulsion composition preferably contains a plasticizer for the purpose of adjusting the film forming temperature. As the plasticizer, dibutyl phthalate is preferable.

  In addition, in order to adjust the drying property, setting property, viscosity, film-forming property, etc., the aqueous emulsion composition has various organic solvents such as toluene, perchlene, dichlorobenzene and trichlorobenzene, and various structures such as glycol ethers. Various additives such as a film auxiliary, nonionic, anionic and cationic surfactants, antifoaming agents, antifreezing agents, antiseptics, and rust inhibitors may be contained.

  Hereinafter, the present invention will be described in more detail with reference to examples. In the following examples and comparative examples, unless otherwise specified, parts and% represent parts by mass and mass%, respectively.

In addition, the monomer (monomer A) which has the silyl group used by the Example and the comparative example is as follows.
MAmPTMS: 3-methacrylamideamidopropyltrimethoxysilane MAmPTES: 3-methacrylamideamidopropyltriethoxysilane MAmBTMS: 4-methacrylamidobutyltrimethoxysilane MAmOTMS: 8-methacrylamidooctyltrimethoxysilane MAmDDTMS: 12-methacrylamidododecyltrimethoxysilane MAmODTMS: 18-methacrylamidooctadecyltrimethoxysilane AMBTMS: 3-acrylamido-3-methylbutyltrimethoxysilane 4-PTMS: 4-pentenyltrimethoxysilane VMS: vinyltrimethoxysilane MAMTMTS: methacrylamidomethyltrimethoxysilane AMPTMS: 2 -Acrylamide-2-methylpropyltrimethoxysilane

[Synthesis of silyl group-containing PVA]
PVA is produced by the following method, the degree of saponification, the content of monomer units having a group represented by the above formula (1) (S) (in some examples, monomer units having a silyl group) Content) and viscosity average degree of polymerization (P). Moreover, according to the following evaluation methods, the performance of the emulsion produced using the emulsion which used PVA which has group represented by the said Formula (1) as an emulsion polymerization stabilizer, and a post-addition processing agent was evaluated.

[Analysis method of PVA]
Analysis of PVA was performed according to the method described in JIS-K6726 unless otherwise specified.

[Synthesis Example 1] Production of PVA1 Into a 6 L separable flask equipped with a stirrer, a reflux condenser, a nitrogen introduction tube, a comonomer dropping port and an initiator addition port, 1,500 g of vinyl acetate, 500 g of methanol, the above formula (1 ) MAmPTMS 1.87 g as a monomer (monomer A) having a group represented by) was charged, and the inside of the system was purged with nitrogen for 30 minutes while carrying out nitrogen bubbling. Further, a comonomer solution having a concentration of 8% was prepared by dissolving MAmPTMS in methanol as a delay solution, and nitrogen substitution was performed by bubbling nitrogen gas. The temperature of the reactor was increased, and when the internal temperature reached 60 ° C., 0.8 g of 2,2′-azobisisobutyronitrile (AIBN) was added to initiate polymerization. The delay solution was added dropwise to polymerize the monomer composition (ratio of vinyl acetate and monomer A (MAmPTMS)) in the polymerization solution at a constant rate for 2.7 hours at 60 ° C. and then cooled to stop the polymerization. . The total amount of comonomer solution (sequentially added solution) added until the polymerization was stopped was 99 g. Further, the solid content concentration when the polymerization was stopped was 29.0%. Subsequently, an unreacted vinyl acetate monomer is removed while sometimes adding methanol under reduced pressure at 30 ° C., and a methanol solution containing 40% of polyvinyl acetate (PVAc) having a group represented by the above formula (1) Got. Furthermore, a methanol solution containing 10% by mass of methanol and sodium hydroxide was added so that the molar ratio of sodium hydroxide to the vinyl acetate unit in PVAc was 0.04 and the solid content concentration of PVAc was 30% by mass. In this order, with stirring, the saponification reaction was started at 40 ° C. A gel was formed in about 5 minutes after the addition of the alkaline solution. This gel-like material was pulverized with a pulverizer and allowed to stand at 40 ° C. for 1 hour to allow saponification to proceed. Then, methyl acetate was added to neutralize the remaining alkali. After confirming the completion of neutralization using a phenolphthalein indicator, the mixture was filtered to obtain a white solid. Methanol was added thereto, and the mixture was allowed to wash at room temperature for 3 hours. After repeating the above washing operation three times, the white solid obtained by centrifugal drainage was left in a dryer at 65 ° C. for 2 days to obtain PVA1 having a group represented by the above formula (1). PVA1 had a viscosity average polymerization degree (P) of 1,700 and a saponification degree of 98.6 mol%.

The content of the monomer unit having the group represented by the above formula (1) of the obtained PVA1 (content of the monomer unit having a silyl group) is the proton NMR of PVAc which is a precursor of this PVA. I asked for it. Specifically, after reprecipitation purification of the obtained PVAc was sufficiently performed three times or more with n-hexane / acetone, drying was performed under reduced pressure at 50 ° C. for 2 days to prepare a PVAc for analysis. This PVAc was dissolved in CDCl ₃ and measured at room temperature using 500 MHz proton NMR (JEOL GX-500). From the peak α (4.7 to 5.2 ppm) derived from the main chain methine of the vinyl acetate unit and the peak β (3.4 to 3.8 ppm) derived from the methyl of the methoxy group of the monomer A unit, the following formula is obtained. The content (S) of the monomer unit having a group represented by the formula (1) was calculated. In PVA1, the content (S) was 0.5 mol%. The results of analyzing the obtained PVA are shown in Table 1.
Content of monomer unit having group represented by formula (1) (S: mol%)
= {(Peak area of β / 9) / (peak area of α + (peak area of β / 9))} × 100

[Synthesis Examples 2 to 21 and Comparative Synthesis Examples 1 to 15] Manufacture of PVA2 to PVA36 Polymerization conditions such as the amount of vinyl acetate and methanol, the type and addition amount of monomer A, the concentration of PVAc during saponification, and the vinyl acetate unit PVA2 to PVA36 were obtained in the same manner as in Synthesis Example 1 except that the saponification conditions such as the molar ratio of sodium hydroxide were changed as shown in Table 1. Table 1 shows the results of analysis for each obtained PVA. In Table 1, the content (S) of Comparative Synthesis Examples 1 to 15 is the content of monomer units having a silyl group other than the monomer unit having a group represented by Formula (1). Including.

  Hereinafter, each PVA obtained above was divided into <when used as a stabilizer for emulsion polymerization> and <when used as a post-addition treatment agent>, and each PVA and an aqueous emulsion composition containing the same were evaluated. .

<Evaluation when used as a stabilizer for emulsion polymerization>
[Emulsion polymerization stability of Synthesis Example 1 (PVA1)]
(Emulsion polymerization of vinyl acetate)
In a 1 L glass polymerization vessel provided with a reflux condenser, a dropping funnel, a thermometer, and a nitrogen blowing port, ion exchange water 350 g, PVA1 (content of monomer unit having silyl group (S) 0.5 mol%, 26.5 g of a saponification degree of 98.6 mol% and a polymerization degree of 1,700) were charged and completely dissolved at 95 ° C. Next, this aqueous PVA solution was cooled, purged with nitrogen, added with 35.3 g of vinyl acetate while stirring at 200 rpm, heated to 60 ° C., and then added with a hydrogen peroxide / tartaric acid-based redox initiator for polymerization. Started. From 15 minutes after the start of the polymerization, 318.1 g of vinyl acetate was continuously added over 3 hours, and then the polymerization was completed to obtain a polyvinyl acetate emulsion having a solid content concentration of 50.1% and a particle size of 2 μm. Table 2 shows the emulsion polymerization stability of the emulsion polymerization stabilizer. In Table 2, “◯” indicates that the obtained emulsion is not aggregated / gelled and the emulsion polymerization stability is good, and “×” indicates that the obtained emulsion is aggregated and emulsion polymerization is performed. Indicates that the stability was poor. In addition, “* 1” indicates that PVA was not completely dissolved in the aqueous solution and thus could not be evaluated.

[Emulsion polymerization stability of Synthesis Examples 2 to 21 and Comparative Synthesis Examples 1 to 15 (PVA2 to PVA36)]
Evaluation was performed in the same manner as in [Emulsion polymerization stability of Synthesis Example 1 (PVA1)] except that the PVA shown in Table 2 was used instead of the PVA1 used above, and the amount used was changed as shown in Table 2. did. The results are also shown in Table 2.

(Preparation of aqueous emulsion composition)
[Example 1]
An aqueous emulsion composition was prepared by adding 5 parts by mass of dibutyl phthalate as a plasticizer to 100 parts by mass of the solid content of the polyvinyl acetate emulsion obtained in [Emulsion polymerization stability of Synthesis Example 1 (PVA1)]. . The water resistance and viscosity storage stability (pot life) of the film of this aqueous emulsion composition were evaluated as follows. The evaluation results are shown in Table 3.

[Water resistance evaluation (1)]
(Water resistance of the film)
The prepared aqueous emulsion composition was cast on a PET film at 20 ° C. and 65% RH, and dried for 7 days to obtain a dry film having a thickness of 500 μm. The film was punched into a diameter of 2.5 cm, and the film was immersed in water at 20 ° C. for 24 hours, and the water absorption rate of the film [{(mass after immersion−mass before immersion) / mass before immersion} × 100] (%) and determined according to the following criteria.
S: Less than 20.0% A: 20.0% or more and less than 22.0% B: 22.0% or more and less than 26.0% C: 26.0% or more and less than 30.0% D: 30.0% or more Less than 35.0% E: 35.0% or more

[Water resistance evaluation (2)]
(Hot water resistant adhesion)
The aqueous emulsion composition prepared above was applied to a hook material (mesh) at a thickness of 150 g / m ² , and bonded together and pressed with a load of 7 kg / m ² for 16 hours. The pressure was then released and after curing at 20 ° C. and 65% RH for 5 days, after being immersed in water at 60 ° C. for 3 hours, cooled in water at room temperature, and measured for compressive shear strength in the wet state. Judgment was made according to criteria.
A: 25 kg / cm ² or more B: 20 kg / cm ² or more and less than 25 kg / cm ² C: 15 kg / cm ² or more and less than 20 kg / cm ² D: 10 kg / cm ² or more and less than 15 kg / cm ² E: Less than 10 kg / cm ²

[Viscosity storage stability (pot life)]
The prepared aqueous emulsion composition was allowed to stand in a thermostatic bath at 30 ° C., and the viscosity immediately after the temperature of the aqueous emulsion composition reached 30 ° C. and the viscosity after standing at 30 ° C. for 30 days were measured ( The viscosity was measured at 20 rpm using a BH viscometer). A value obtained by dividing the viscosity after 30 days by the viscosity immediately after the temperature of the aqueous emulsion composition became 30 ° C. (after 30 days / immediately) was determined, and this was determined as the viscosity ratio (times) according to the following criteria. . The results are shown in Table 3.
A: Less than 1.5 times B: 1.5 times or more and less than 2.0 times C: 2.0 times or more and less than 3.0 times D: 3.0 times or more but not gelled E: Fluidity Has lost its gel

[Examples 2 to 21 and Comparative Examples 1 to 15]
Instead of the polyvinyl acetate emulsion obtained in [Emulsion polymerization stability of Synthesis Example 1 (PVA1)], [Emulsion polymerization stability of Synthesis Examples 2 to 21 and Comparative Synthesis Examples 1 to 15 (PVA2 to PVA36)] An aqueous emulsion composition was prepared and evaluated in the same manner as in Example 1 except that the polyvinyl acetate emulsion obtained in 1 was used. In Table 3, “* 1” indicates that PVA was not completely dissolved in the aqueous solution and thus could not be evaluated, and “* 2” could not be measured because the obtained emulsion was agglomerated. It shows that.

  As shown in Table 2, it can be seen that the emulsion polymerization stabilizer used in Synthesis Examples 1 to 21 is excellent in emulsion polymerization stability. Furthermore, as Table 3 shows, it turns out that the aqueous | water-based emulsion composition prepared in Examples 1-21 is excellent in the water resistance of the membrane | film | coat obtained, the water-resistant adhesive force (to wood), and the viscosity standing stability. Here, if the viscosity storage stability is D or more, it is assumed that the viscosity storage stability is practically sufficient, and if the other two items are all C or more, both water resistance and viscosity storage stability are compatible. Assume that it is done. Furthermore, PVA viscosity average polymerization degree (P), saponification degree, monomer unit structure, content rate (S), and product of viscosity average polymerization degree (P) and content rate (S) (P × S) are specified. The aqueous emulsion compositions of Example 1, Example 9, and Examples 15 to 18 were particularly excellent in water resistance of the resulting films, water-resistant adhesive strength to wood, and viscosity storage stability (viscosity storage stability was high). B is an evaluation of B or higher, and all other two items are A or higher). In addition, it turns out that the water-based emulsion composition of Examples 12, 14 and 19 has a slight reduction in water resistance and water-resistant adhesive strength of the resulting film. This is thought to be due to a decrease in the viscosity average degree of polymerization (P), the degree of saponification, and the difference in the structure of the monomer units.

  On the other hand, when PVA does not satisfy the prescribed requirements (Comparative Synthesis Examples 1 to 15 and Comparative Examples 1 to 15), the emulsion polymerization stabilizer does not have sufficient emulsion polymerization stability, or prepared aqueous emulsion composition It can be seen that the water resistance of the resulting film, the water-resistant adhesion to wood and the viscosity storage stability are reduced.

<Evaluation when used as a post-addition treatment agent>
(Emulsion polymerization of base vinyl acetate emulsion)
In a 1 L glass polymerization vessel provided with a reflux condenser, a dropping funnel, a thermometer, and a nitrogen blowing port, ion-exchanged water 350 g, PVA-217 (manufactured by Kuraray Co., Ltd., saponification degree 88.0 mol%, polymerization degree 1, 700) 26.5 g was charged and completely dissolved at 95 ° C. Next, this aqueous PVA solution was cooled, purged with nitrogen, added with 35.3 g of vinyl acetate while stirring at 200 rpm, heated to 60 ° C., and then added with a hydrogen peroxide / tartaric acid-based redox initiator for polymerization. Started. After 15 minutes from the start of polymerization, 318.1 g of vinyl acetate was continuously added over 3 hours, and then the polymerization was completed to obtain a polyvinyl acetate emulsion having a solid content of 50.3% and a particle size of 1.8 μm.

(Preparation of aqueous emulsion composition)
[Example 22]
To 100 parts by mass of the solid content of the polyvinyl acetate emulsion obtained in the above (emulsion polymerization of the base vinyl acetate emulsion), 20 parts by mass of a 15% aqueous solution of PVA1 is added and mixed, and further 5 parts by mass of dibutyl phthalate as a plasticizer. An aqueous emulsion composition was prepared by addition and mixing. The water resistant adhesive strength of this aqueous emulsion composition was evaluated in the following manner. The evaluation results are shown in Table 4.

[Hot water resistant adhesive strength]
The aqueous emulsion composition prepared above was applied to a hook material (mesh) at a thickness of 150 g / m ² , and bonded together and pressed with a load of 7 kg / m ² for 16 hours. The pressure was then released and after curing at 20 ° C. and 65% RH for 5 days, after being immersed in water at 60 ° C. for 3 hours, cooled in water at room temperature, and measured for compressive shear strength in the wet state. Judgment was made according to criteria.
A: 20 kg / cm ² or more B: 15 kg / cm ² or more and less than 20 kg / cm ² C: 10 kg / cm ² or more and less than 15 kg / cm ² D: 5 kg / cm ² or more and less than 10 kg / cm ² E: Less than 5 kg / cm ²

[Viscosity storage stability (pot life)]
The prepared aqueous emulsion composition was allowed to stand in a thermostatic bath at 30 ° C., and the viscosity immediately after the temperature of the aqueous emulsion composition reached 30 ° C. and the viscosity after standing at 30 ° C. for 30 days were measured ( The viscosity was measured at 20 rpm using a BH viscometer). A value obtained by dividing the viscosity after 30 days by the viscosity immediately after the temperature of the aqueous emulsion composition became 30 ° C. (after 30 days / immediately) was determined, and this was determined as the viscosity ratio (times) according to the following criteria. . The results are shown in Table 4.
A: Less than 1.2 times B: 1.2 times or more and less than 1.5 times C: 1.5 times or more and less than 2.0 times D: 2.0 times or more but not gelled E: Fluidity Has lost its gel

[Examples 22 to 42 and Comparative Examples 16 to 30]
An aqueous emulsion composition was prepared and evaluated in the same manner as in Example 22 except that PVA shown in Table 4 was added and mixed instead of PVA1 added and mixed in Example 22.

  As shown in Table 4, it can be seen that the aqueous emulsion compositions prepared in Examples 22 to 42 are excellent in water-resistant adhesive strength (to wood) and viscosity standing stability. Here, if the viscosity storage stability is D or more, it is assumed that the viscosity storage stability is practically sufficient, and that the water-resistant adhesive strength is C or more can achieve both water resistance and viscosity storage stability. Assume that Furthermore, PVA viscosity average polymerization degree (P), saponification degree, monomer unit structure, content rate (S), and product of viscosity average polymerization degree (P) and content rate (S) (P × S) are specified. The aqueous emulsion compositions of Example 22, Example 30, Example 31, Example 34, Examples 36 to 39, Example 41, and Example 42 are particularly excellent in water-resistant adhesion to wood and viscosity standing stability. Excellent (viscosity storage stability is evaluated as C or higher, and water-resistant adhesive strength is A or higher). In addition, it turns out that the water-based adhesive strength of the aqueous emulsion composition of Example 33 falls a little. This is considered to be caused by a decrease in the viscosity average degree of polymerization (P) and the product (P × S) of the viscosity average degree of polymerization (P) and the content rate (S).

  On the other hand, when PVA does not satisfy the prescribed requirements (Comparative Examples 16 to 30), it can be seen that the water-based adhesive strength and viscosity storage stability with respect to the wood are reduced for the prepared aqueous emulsion compositions.

  The aqueous emulsion composition of the present invention can exhibit excellent emulsion polymerization stability when used as a stabilizer for emulsion polymerization, and can achieve both the water resistance of the resulting emulsion film and the viscosity standing stability. In addition, when it is used as a post-addition treatment agent after emulsion polymerization, it contains a vinyl alcohol polymer that can achieve both the water resistance and the viscosity standing stability of the resulting emulsion film. Therefore, the aqueous emulsion composition is suitably used for various adhesives for paper, woodwork, plastics and the like.

Claims (8)

A vinyl alcohol polymer containing a monomer unit having a group represented by the following formula (1) and satisfying the following formula (I), and an aqueous emulsion composition containing the vinyl polymer.

(In Formula (1), R ¹ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. R ² is an alkoxyl group, an acyloxyl group, or a group represented by OM. M is a hydrogen atom, R ³ and R ⁴ are each independently a hydrogen atom or an alkyl group, each of which represents an alkyl group, an alkoxyl group or an acyloxyl group represented by R ^{1 to} R ^4. May be substituted with a substituent containing an oxygen atom or a nitrogen atom, m is an integer of 0 to 2. n is an integer of 3 or more, and there are a plurality of R ^{1 to} R ⁴ , respectively. In the case, a plurality of each R ^{1 to} R ⁴ independently satisfy the above definition.)
370 ≦ P × S ≦ 6,000 (I)
P: Viscosity average degree of polymerization S: Content of the monomer unit (mol%) The aqueous emulsion composition according to claim 1, wherein the vinyl alcohol polymer further satisfies the following formulas (II) and (III).
200 ≦ P ≦ 4,000 (II)
0.1 ≦ S ≦ 10 (III)
P: Viscosity average degree of polymerization S: Content of the monomer unit (mol%)   The aqueous emulsion composition according to claim 1 or 2, wherein n in the formula (1) is an integer of 6 to 20. The aqueous emulsion composition according to claim 1, wherein the monomer unit is represented by the following formula (2).

(In the formula (2), R ^{1 to} R ⁴ , m and n have the same meanings as in the formula (1). X is a direct bond, a divalent hydrocarbon group, a divalent hydrocarbon group containing an oxygen atom or a nitrogen atom. (It is an organic group. R ⁵ is a hydrogen atom or a methyl group.) The stabilizer for emulsion polymerization according to claim 4, wherein X in the formula (2) is represented by the following formula (3).
-CO-NR ^6- * (3)
(In the formula (3), R ⁶ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. * Indicates a bonding position with the group represented by the above formula (1).) The aqueous emulsion composition according to claim 5, wherein R ⁶ in the formula (3) is a hydrogen atom, and n in the formula (2) is an integer of 3 to 12.   The method for producing an aqueous emulsion composition according to any one of claims 1 to 6, wherein the vinyl alcohol polymer is used as a stabilizer for emulsion polymerization and a vinyl monomer is polymerized.   The method for producing an aqueous emulsion composition according to any one of claims 1 to 6, wherein the vinyl alcohol polymer is added to an aqueous emulsion containing a vinyl polymer.