JPWO2016013220A1 - Aqueous emulsion - Google Patents

Abstract

In the present invention, an ethylenically unsaturated monomer (B) and a monomer (C) represented by the following formula (I) or (II) are copolymerized in the presence of the polyvinyl alcohol resin (A). It is related with the aqueous emulsion characterized by being obtained.

Description

  The present invention relates to an aqueous emulsion that provides a film having excellent heat resistance and water resistance, warm water resistance, and boiling water resistance.

  Conventionally, an aqueous emulsion containing a vinyl acetate polymer resin obtained by polymerizing vinyl acetate using polyvinyl alcohol (hereinafter sometimes abbreviated as PVA) as a protective colloid is used for paper processing, woodworking and fiber processing. Widely used in adhesives and paints. In particular, when water resistance and adhesiveness are required, PVA is used as a protective colloid and a carboxyl group-containing unsaturated monomer is widely used. However, the film obtained from the aqueous emulsion thus obtained has problems that the adhesion and water resistance are improved, but the heat resistance is poor, and the hot water resistance, boiling water resistance and the like are still insufficient. .

  Therefore, several solutions have been proposed to solve these problems. For example, Patent Document 1 proposes an emulsion adhesive containing a polyaldehyde capable of releasing an aldehyde group in an acidic medium. However, even with this method, water resistance is still insufficient. Patent Document 2 proposes an emulsion obtained by copolymerizing a vinyl acetate monomer and N-methylolacrylamide. However, this method has insufficient water resistance at low temperatures, and there is an environmental problem that formaldehyde is generated when used as an adhesive. Patent Document 3 discloses emulsion modification (co) polymerization of vinyl acetate or vinyl acetate and (meth) acrylates using a modified PVA containing ethylene (hereinafter simply referred to as “ethylene-modified PVA”) as a protective colloid. It has been proposed to do. However, although these techniques certainly improve heat resistance and hot water resistance to some extent, they are still insufficient, and no satisfactory results have been obtained in terms of final adhesion strength and boiling water resistance. Patent Document 4 proposes using ethylene-modified PVA as a protective colloid and using a (co) polymer of a carboxyl group-containing unsaturated monomer or amide-modified PVA together when vinyl acetate is polymerized. However, this method is still insufficient in heat resistance. Patent Document 5 proposes an aqueous dispersion composed of polymer particles having an acetal or aldehyde functional group. However, with this method, the strength of the resulting coating film is low and the heat resistance is still insufficient.

JP-A-8-60116 JP-A-10-121017 JP-A-11-106727 JP 2001-123138 A Special table 2003-517499 gazette

  Accordingly, an object of the present invention is to provide an aqueous emulsion that provides a film having excellent heat resistance and excellent water resistance, warm water resistance, and boiling water resistance. Another object of the present invention is to provide an aqueous emulsion having excellent coloration resistance of the film (particularly coloration resistance when the film is heated).

（式中、Ｒ¹は水素原子、炭素数１〜８の直鎖状のアルキル基又は−ＣＨ₂−ＣＯＯＭであり、ここでＭは水素原子、メチル基、アルカリ金属又はアンモニウム基であり、Ｒ²及びＲ³は同一又は異なって、炭素数１〜８のアルキル基又は炭素数２〜８のアルキルカルボニル基であり、Ｒ⁴は水素原子又は−ＣＯＯＭであり、ここでＭは水素原子、メチル基、アルカリ金属又はアンモニウム基であり、Ｘは−（ＣＨ₂）_n−、−ＣＯ−ＮＨ−（ＣＨ₂）_n−、−ＮＨ−ＣＯ−（ＣＨ₂）_n−、−ＣＯ−（ＣＨ₂）_n−、−ＣＯ−Ｏ−（ＣＨ₂）_n−、−Ｏ−ＣＯ−（ＣＨ₂）_n−、−ＮＲ⁵−ＣＯ−（ＣＨ₂）_n−、又は−ＣＯ−ＮＲ⁵−（ＣＨ₂）_n−であり、ここでＲ⁵は水素原子又は炭素数１〜４のアルキル基を意味し、ｎは０〜８の整数である。）

（式中、Ｒ¹、Ｒ⁴及びＸは、上記と同一意味を有し、Ｒ⁶は−（ＣＨ₂−ＣＨ₂）_m−であり、ｍは１〜３の整数である。）Therefore, as a result of intensive studies, the present inventors have represented an ethylenically unsaturated monomer (B) and the following formula (I) or (II) in the presence of the polyvinyl alcohol resin (A). The present inventors have found that an aqueous emulsion obtained by copolymerizing the monomer (C) can solve the above-mentioned problems, and has completed the present invention.

(In the formula, R ¹ is a hydrogen atom, a linear alkyl group having 1 to 8 carbon atoms or —CH ₂ —COOM, where M is a hydrogen atom, a methyl group, an alkali metal or an ammonium group; ² and R ³ are the same or different and are an alkyl group having 1 to 8 carbon atoms or an alkylcarbonyl group having 2 to 8 carbon atoms, R ⁴ is a hydrogen atom or —COOM, where M is a hydrogen atom, methyl X is — (CH ₂ ) _n —, —CO—NH— (CH ₂ ) _n —, —NH—CO— (CH ₂ ) _n —, —CO— (CH ₂ ) _N —, —CO—O— (CH ₂ ) _n —, —O—CO— (CH ₂ ) _n —, —NR ⁵ —CO— (CH ₂ ) _n —, or —CO—NR ⁵ — (CH ₂ ) _n- , wherein R ⁵ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and n is an integer of 0 to 8 .)

(Wherein R ¹ , R ⁴ and X have the same meaning as described above, R ⁶ is — (CH ₂ —CH ₂ ) _m —, and m is an integer of 1 to 3).

  According to the present invention, it is possible to provide an aqueous emulsion that is excellent in heat resistance and excellent in water resistance, warm water resistance, and boiling water resistance. Moreover, according to this invention, the aqueous emulsion which is excellent in the coloring resistance (especially coloring resistance at the time of heating a film) of a film | membrane can be provided.

  Hereinafter, the present invention will be described in detail. The aqueous emulsion of the present invention uses a polyvinyl alcohol resin (A) as a protective colloid, an ethylenically unsaturated monomer (B), and a monomer represented by the following formula (I) or (II) (C ) And a copolymer resin obtained by copolymerization. In this specification, (meth) acryl is a general term for acrylic and methacrylic, and the same applies to similar expressions.

（式中、Ｒ¹は水素原子、炭素数１〜８の直鎖状のアルキル基又は−ＣＨ₂−ＣＯＯＭであり、ここでＭは水素原子、メチル基、アルカリ金属又はアンモニウム基であり、Ｒ²及びＲ³は同一又は異なって、炭素数１〜８のアルキル基又は炭素数２〜８のアルキルカルボニル基であり、Ｒ⁴は水素原子又は−ＣＯＯＭであり、ここでＭは水素原子、メチル基、アルカリ金属又はアンモニウム基であり、Ｘは−（ＣＨ₂）_n−、−ＣＯ−ＮＨ−（ＣＨ₂）_n−、−ＮＨ−ＣＯ−（ＣＨ₂）_n−、−ＣＯ−（ＣＨ₂）_n−、−ＣＯ−Ｏ−（ＣＨ₂）_n−、−Ｏ−ＣＯ−（ＣＨ₂）_n−、−ＮＲ⁵−ＣＯ−（ＣＨ₂）_n−、又は−ＣＯ−ＮＲ⁵−（ＣＨ₂）_n−であり、ここでＲ⁵は水素原子又は炭素数１〜４のアルキル基であり、ｎは０、１、２、３、４、５、６、７又は８である。）

(In the formula, R ¹ is a hydrogen atom, a linear alkyl group having 1 to 8 carbon atoms or —CH ₂ —COOM, where M is a hydrogen atom, a methyl group, an alkali metal or an ammonium group; ² and R ³ are the same or different and are an alkyl group having 1 to 8 carbon atoms or an alkylcarbonyl group having 2 to 8 carbon atoms, R ⁴ is a hydrogen atom or —COOM, where M is a hydrogen atom, methyl X is — (CH ₂ ) _n —, —CO—NH— (CH ₂ ) _n —, —NH—CO— (CH ₂ ) _n —, —CO— (CH ₂ ) _N —, —CO—O— (CH ₂ ) _n —, —O—CO— (CH ₂ ) _n —, —NR ⁵ —CO— (CH ₂ ) _n —, or —CO—NR ⁵ — (CH ₂ ) _n- , wherein R ⁵ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and n is 0, 1, 2, 3 4, 5, 6, 7 or 8.)

（式中、Ｒ¹は水素原子、炭素数１〜８の直鎖状のアルキル基又は−ＣＨ₂−ＣＯＯＭであり、ここでＭは水素原子、メチル基、アルカリ金属又はアンモニウム基であり、Ｒ⁴は水素原子又は−ＣＯＯＭであり、ここでＭは水素原子、メチル基、アルカリ金属又はアンモニウム基であり、Ｘは−（ＣＨ₂）_n−、−ＣＯ−ＮＨ−（ＣＨ₂）_n−、−ＮＨ−ＣＯ−（ＣＨ₂）_n−、−ＣＯ−（ＣＨ₂）_n−、−ＣＯ−Ｏ−（ＣＨ₂）_n−、−Ｏ−ＣＯ−（ＣＨ₂）_n−、−ＮＲ⁵−ＣＯ−（ＣＨ₂）_n−、又は−ＣＯ−ＮＲ⁵−（ＣＨ₂）_n−であり、ここでＲ⁵は水素原子又は炭素数１〜４のアルキル基であり、ｎは０、１、２、３、４、５、６、７又は８であり、Ｒ⁶は−（ＣＨ₂−ＣＨ₂）_m−であり、ｍは１、２又は３である。）

(In the formula, R ¹ is a hydrogen atom, a linear alkyl group having 1 to 8 carbon atoms or —CH ₂ —COOM, where M is a hydrogen atom, a methyl group, an alkali metal or an ammonium group; ⁴ is a hydrogen atom or —COOM, wherein M is a hydrogen atom, a methyl group, an alkali metal or an ammonium group, and X is — (CH ₂ ) _n —, —CO—NH— (CH ₂ ) _n —, _{-NH-CO- (CH 2) n} -, - CO- (CH 2) n -, - CO-O- (CH 2) n -, - O-CO- (CH 2) n -, - NR 5 - CO— (CH ₂ ) _n —, or —CO—NR ⁵ — (CH ₂ ) _n —, wherein R ⁵ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and n is 0, 1, 2, 3, 4, 5, ⁶ , 7 or 8; R ⁶ is — (CH ₂ —CH ₂ ) _m —, and m is 1, 2 or 3.)

  By copolymerizing the ethylenically unsaturated monomer (B) and the monomer (C) represented by the above formula (I) or (II) using the polyvinyl alcohol resin (A) as a protective colloid. The aqueous emulsion of the present invention is obtained.

In the above formula (I), examples of the linear alkyl group having 1 to 8 carbon atoms in R ¹ include, for example, methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n- A hexyl group, n-heptyl group, and n-octyl group are mentioned, and a methyl group is preferable. Examples of the alkyl group having 1 to 8 carbon atoms in R ² and R ³ include, for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group N-pentyl group, isopentyl group, sec-pentyl group, neopentyl group, tert-pentyl group, 1-ethylpropyl group, n-hexyl group, isohexyl group, 1,1-dimethylbutyl group, 2,2-dimethylbutyl Group, 3,3-dimethylbutyl group, 2-ethylbutyl group, n-heptyl group, n-octyl group and the like. Among these, a group having 1 to 6 carbon atoms is preferable, and a group having 1 to 3 carbon atoms. Are more preferable, and a methyl group, an ethyl group, or an n-propyl group is more preferable. Examples of the alkali metal represented by M in R ¹ and R ⁴ include lithium, sodium, potassium, rubidium, cesium, and the like. Lithium, sodium, or potassium is preferable, and sodium or potassium is more preferable. Examples of the alkylcarbonyl group in R ² and R ³ include an acetyl group, a propanoyl group, a butanoyl group, a pentanoyl group, a hexanoyl group, a heptanoyl group, an octanoyl group, and the like. An acetyl group, a propanoyl group, a butanoyl group, a pentanoyl group Or a hexanoyl group is preferable. X in the above formula (I) is preferably — (CH ₂ ) _n —. N in the formula (I) is preferably 0, 1, 2, 3, 4, 5 or 6. Examples of the alkyl group having 1 to 4 carbon atoms in R ⁵ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and a tert-butyl group. .

In the above formula (II), the alkyl groups of R ¹ and R ⁵ , M and the alkali metal are the same as in the above formula (I). In the above formula (II), m of R ⁶ is preferably 1, 2, and more preferably 1. X in the formula (II) is preferably — (CH ₂ ) _n —. N in the formula (II) is preferably 0, 1, 2, 3, 4, 5 or 6.

The monomer (C) represented by the formula (I) or (II) is not particularly limited, and examples thereof include the following:
Acetalized products of (meth) acrolein such as (meth) acrolein dimethyl acetal, (meth) acrolein diethyl acetal, 2-vinyl-1,3-dioxolane, 2-isopropenyl-1,3-dioxolane, 3-methyl-3- Acetalized products of 3-methyl-3-butenal such as butenal dimethyl acetal, 3-methyl-3-butenal diethyl acetal, 2- (2-methyl-2-propenyl) -1,3-dioxolane, 3- Acetalized products of 3-butenal such as butenal dimethyl acetal, 3-butenal diethyl acetal, 2- (2-propenyl) -1,3-dioxolane, 4-pentenal dimethyl acetal, 4-pentenal diethyl acetal, 4-Pen such as 2- (3-butenyl) -1,3-dioxolane Acetalized product of nal, 5-hexenal dimethyl acetal, 5-hexenal diethyl acetal, acetalized product of 5-hexenal such as 2- (5-pentenyl) -1,3-dioxolane, 6-heptenal dimethyl acetal, 6-hept Acetalized products of 6-heptenal such as tenal diethyl acetal, 2- (6-hexenyl) -1,3-dioxolane, 7-octenal dimethyl acetal, 7-octenal diethyl acetal, 2- (1-heptenyl) -1 An acetalized product of an aliphatic aldehyde having an ethylenically unsaturated double bond, such as an acetalized product of 7-octenal such as 1,3-dioxolane, 2- (6-heptenyl) -1,3-dioxolane;
N- (2,2-dimethoxyethyl) (meth) acrylamide, N- (2,2-diethoxyethyl) (meth) acrylamide, N- (2,2-diisopropoxyethyl) (meth) acrylamide, N- (2,2-dibutoxyethyl) (meth) acrylamide, N- (2,2-di-t-butoxyethyl) (meth) acrylamide, N- (3,3-dimethoxypropyl) (meth) acrylamide, N- (3,3-diethoxypropyl) (meth) acrylamide, N- (3,3-diisopropoxypropyl) (meth) acrylamide, N- (3,3-dibutoxypropyl) (meth) acrylamide, N- ( 3,3-di-t-butoxypropyl) (meth) acrylamide, N- (4,4-dimethoxybutyl) (meth) acrylamide, N- (4,4-di Toxibutyl) (meth) acrylamide, N- (4,4-diisopropoxybutyl) (meth) acrylamide, N- (4,4-dibutoxybutyl) (meth) acrylamide, N- (4,4-di-t -Butoxybutyl) (meth) acrylamide, N-methyl-N- (2,2-dimethoxyethyl) (meth) acrylamide, N-methyl-N- (2,2-diethoxyethyl) (meth) acrylamide, N- Methyl-N- (2,2-diisopropoxyethyl) (meth) acrylamide, N-methyl-N- (2,2-dibutoxyethyl) (meth) acrylamide, N-methyl-N- (2,2- Dialkoxyalkyl (meth) acrylamide compounds such as di-t-butoxyethyl) (meth) acrylamide; 4-{(2,2-dimethoxyethyl) amino -4-oxo-2-butenoic acid, 4-{(2,2-diethoxyethyl) amino} -4-oxo-2-butenoic acid, 4-{(2,2-diisopropoxyethyl) amino}- Butenoic acids having a dialkoxy group such as 4-oxo-2-butenoic acid and 4-{(2,2-dibutoxyethyl) amino} -4-oxo-2-butenoic acid; 5,5-dimethoxy-3- Oxo-1-pentene, 5,5-diethoxy-3-oxo-1-pentene, 5,5-diisopropoxy-3-oxo-1-pentene, 5,5-dibutoxy-3-oxo-1-pentene, etc. Pentenes having a dialkoxy group: 3- [N- (2,2-dimethoxyethyl) carbamoyl] propenoic acid, 3- [N- (2,2-diethoxyethyl) carbamoyl] propenoic acid, 3- [N -(2,2-diisopropo 1 such as xylethyl) carbamoyl] propenoic acid, 3-[(N-2,2-dibutoxyethyl) carbamoyl] propenoic acid, 3- [N- (2,2-di-t-butoxyethyl) carbamoyl] propenoic acid Propenoic acid compound having two alkoxy groups in the molecule; 3- [N- (2,2-dimethoxyethyl) carbamoyl] methyl propenoate, 3- [N- (2,2-diethoxyethyl) carbamoyl] Methyl propenoate, methyl 3- [N- (2,2-diisopropoxyethyl) carbamoyl] propenoate, methyl 3- [N- (2,2-dibutoxyethyl) carbamoyl] propenoate, 3- [N- (2,2-di-t-butoxyethyl) carbamoyl] propenoic acid ester compound having two alkoxy groups in one molecule such as methyl propenoate; Dialkoxyalkyl (meta) such as methoxyethyl (meth) acrylate, 2,2-diethoxyethyl (meth) acrylate, 2,2-diisopropoxyethyl (meth) acrylate, 2,2-dibutoxyethyl (meth) acrylate ) Acetalized products of acrylate, etc .; or aliphatic compounds having unsaturated double bonds such as alkyl (meth) acrylamide compounds, acetalized products of butenoic acids, acetalized products of maleic acids, acetalized products of itaconic acids, acetalized products of pentenes, etc. Acetalized product of aldehyde. As carbon number of the said alkoxy group, 1-6 are preferable and 1-4 are more preferable. As carbon number of the alkyl group of the said alkyl (meth) acrylamide type compound or dialkoxyalkyl (meth) acrylate, 1-6 are preferable, 1-4 are more preferable, and 1-2 are more preferable.

  In the aqueous emulsion of the present invention, one or more of the unsaturated monomers (C) described above can be used.

  The monomer unit represented by the formula (I) or (II) is preferably 0.01 to 10% by mass with respect to the total amount of the ethylenically unsaturated monomer unit, and 0.05 to 5 More preferably, it is mass%. When the monomer unit represented by the formula (I) or (II) is 0.01% by mass or less, the heat resistance, water resistance, warm water resistance and boiling water resistance become insufficient, and 10% by mass or more. In this case, polymerization becomes difficult.

  In the present invention, the ethylenically unsaturated monomer (B) used for copolymerization with the monomer (C) represented by the above formula (I) or (II) does not impair the effects of the present invention. Although not particularly limited, for example, vinyl ester monomers, (meth) acrylic acid ester monomers, α, β-unsaturated mono- or dicarboxylic acid monomers, diene monomers, olefin monomers Monomer, (meth) acrylamide monomer, nitrile monomer, aromatic vinyl monomer, heterocyclic vinyl monomer, vinyl ether monomer, allyl monomer, multifunctional Examples include acrylate monomers. These may be used alone or in combination of two or more. Among these, at least one unsaturated monomer selected from the group consisting of vinyl ester monomers and diene monomers is preferable, and vinyl ester monomers are more preferable.

  The vinyl ester monomer is not particularly limited. For example, vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl versatate, vinyl cinnamate, vinyl crotonate, decane. Vinyl acetate, vinyl hexanoate, vinyl octoate, vinyl isononanoate, vinyl trimethyl acetate, vinyl 4-tert-butylbenzene, vinyl 2-ethylhexanoate, vinyl caproate, vinyl caprylate, vinyl laurate, vinyl palmitate , Vinyl stearate, vinyl oleate, vinyl benzoate and the like, and vinyl acetate is particularly preferable from an industrial viewpoint. Although it does not specifically limit as a (meth) acrylic-ester type monomer, For example, (meth) acrylic acid methyl, (meth) acrylic acid ethyl, (meth) acrylic acid n-propyl, (meth) acrylic acid i- Propyl, n-butyl (meth) acrylate, i-butyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, dodecyl (meth) acrylate, (meth) acrylic acid Examples include octadecyl, 2-hydroxyethyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, 2- (dimethylamino) ethyl (meth) acrylate, and the like. The α, β-unsaturated mono- or dicarboxylic acid-based monomer is not particularly limited, and examples thereof include (meth) acrylic acid, crotonic acid, isocrotonic acid, citraconic acid, itaconic acid, maleic acid, maleic anhydride, and fumaric acid. An acid etc. are mentioned. The diene monomer is not particularly limited, and examples thereof include conjugated dienes such as butadiene, isoprene and chloroprene.

  Although it does not specifically limit as an olefin type monomer, For example, monoolefin compounds, such as ethylene, propylene, 1-butene, and isobutene; Halogens, such as vinyl chloride, vinyl bromide, vinylidene chloride, vinyl fluoride, and vinylidene fluoride And olefinic compounds. Although it does not specifically limit as a (meth) acrylamide type monomer, For example, (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, diacetone, for example (Meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, N-methylol (meth) acrylamide and the like can be mentioned. The nitrile monomer is not particularly limited, and examples thereof include (meth) acrylonitrile. Although it does not specifically limit as an aromatic vinyl-type monomer, For example, styrene, (alpha) -methylstyrene, p-methylstyrene, chlorostyrene, (alpha) -butoxystyrene, vinyl naphthalene, vinyl biphenyl, 1-ethyl-2-vinyl Examples include benzene. Although it does not specifically limit as a heterocyclic vinyl type monomer, For example, vinylpyrrolidone etc. are mentioned. The vinyl ether monomer is not particularly limited, and examples thereof include methyl 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 and the like. Can be mentioned. The allylic monomer is not particularly limited, and examples thereof include allyl acetate, allyl chloride, allyl sulfonate, diallyl phthalate, triallyl cyanurate, and triallyl isocyanurate. Although it does not specifically limit as a polyfunctional acrylate-type monomer, For example, a pentaerythritol triacrylate, a pentaerythritol tetraacrylate, a pentaerythritol hexaacrylate, a trimethylol propane triacrylate etc. are mentioned. Furthermore, as the ethylenically unsaturated monomer, vinyl compounds such as vinyl phosphonic acid, vinyl sulfonic acid and salts thereof can be used. These may be used individually by 1 type, and 2 or more types may be mixed and used for them.

（式中、記号は、上記と同一意味を有する。）

（式中、記号は、上記と同一意味を有する。）The saponification degree of PVA (A) used as a protective colloid in the present invention is usually 70 to 99.9 mol%, preferably 75 to 99.5 mol%. When the degree of saponification is less than 70 mol%, the effect as a protective colloid is poor and a stable aqueous emulsion cannot be obtained. On the other hand, when the degree of saponification exceeds 99.9 mol%, the temperature dependency of the viscosity of the resulting aqueous emulsion increases, and the object of the present invention cannot be achieved. In addition, as long as the PVA has a saponification degree in the above range, those having different saponification degrees may be used in combination. The saponification degree is a value obtained by the method described in JIS K 6726 (1994). As long as the PVA has a saponification degree in the above range, it may be unmodified PVA or modified PVA. The modified PVA is not particularly limited. For example, anion-modified PVA such as sulfonic acid group-modified PVA and carboxylic acid group-modified PVA; cation-modified PVA such as quaternary amine group-modified PVA; amide-modified PVA (preferably Diacetone acrylamide-modified PVA); acetoacetyl group-modified PVA; ethylene-modified PVA; modified PVA having an aldehyde group in the side chain; modified containing the structural unit represented by the following formula (III) or (IV) in the main chain PVA etc. are mentioned.

(In the formula, the symbols have the same meaning as described above.)

(In the formula, the symbols have the same meaning as described above.)

  PVA (A) used as these protective colloids may be used alone or in combination of two or more. Among these, at least one PVA selected from the group consisting of anion-modified PVA such as unmodified PVA, ethylene-modified PVA, and carboxylic acid group-modified PVA is preferable. The content of the modifying group is not particularly limited, but may be 0.5 to 10 mol%. Moreover, although it does not specifically limit, As modified PVA used as a protective colloid, modified PVA which has an aldehyde group in a side chain may be excluded.

The viscosity average polymerization degree of the PVA (A) (hereinafter sometimes simply referred to as polymerization degree) may be in a range generally used for emulsion polymerization, and is preferably from 300 to 4000. When the degree of polymerization is 300 or more, sufficient stability at the time of emulsion polymerization is obtained, and when the degree of polymerization is 4000 or less, the solution viscosity at the time of emulsion polymerization does not become too high, and stirring and heat removal are easy. This is preferable because it can be performed. The degree of polymerization is a value determined by the method described in JIS K 6726 (1994). Specifically, when the saponification degree of PVA is less than 99.5 mol%, the intrinsic viscosity [η] (measured in water at 30 ° C.) for the saponified PVA until the saponification degree is 99.5 mol% or more ( Liter / g), the viscosity average degree of polymerization (P) can be determined by the following formula.
P = ([η] × 10 ⁴ /8.29) ^{(1 / 0.62)}

  The usage-amount of polyvinyl alcohol is 2-20 mass% normally with respect to the whole quantity of an ethylenically unsaturated monomer (for example, vinyl acetate), Preferably it is 3-10 mass%. If it is less than 2% by mass, sufficient stability during emulsion polymerization may not be obtained. If it exceeds 20% by mass, the water resistance, warm water resistance and boiling water resistance of the resulting film using the aqueous emulsion may be reduced. In some cases, the temperature dependency of viscosity increases.

  The aqueous emulsion of the present invention comprises the ethylenically unsaturated monomer (B) and the monomer (C) represented by the above formula (I) or (II) in the presence of the polyvinyl alcohol resin (A). It can manufacture by the manufacturing method which has the process of copolymerizing. The aqueous emulsion of the present invention can be produced, for example, by commonly performed emulsion polymerization. Although the temperature at the time of superposition | polymerization changes with the polymerization catalyst to be used, it is 20-100 degreeC normally, Preferably it is 40-90 degreeC, More preferably, it is 50-90 degreeC. The reaction time is not particularly limited and may be appropriately adjusted according to the blending amount of each component, the reaction temperature, and the like.

  The aqueous emulsion of the present invention may contain an alkali metal compound. The alkali metal compound is not particularly limited as long as it contains an alkali metal (sodium, potassium, rubidium, cesium), and may be an alkali metal ion itself or a compound containing an alkali metal.

  The content of alkali metal compound (in terms of alkali metal) can be appropriately selected according to the type of alkali metal compound used, but the content of alkali metal compound (in terms of alkali metal) is the emulsion (solid basis). Usually, it is 100-15000 ppm with respect to the total weight, 120-12000 ppm is more preferable, and 150-8000 ppm is the most preferable. When the content of the alkali metal compound is lower than 100 ppm, the emulsion polymerization stability of the aqueous emulsion may be lowered, and when it exceeds 15000 ppm, the film made of the aqueous emulsion may be colored, which is not preferable. Note that the content of the alkali metal compound may be a value measured by an ICP emission analyzer.

  Specific examples of the compound containing an alkali metal include weakly basic alkali metal salts (for example, alkali metal carbonates, alkali metal acetates, alkali metal bicarbonates, alkali metal phosphates, alkali metal sulfates, alkalis). Metal halide salts, alkali metal nitrates), strongly basic alkali metal compounds (for example, alkali metal hydroxides, alkali metal alkoxides) and the like. These alkali metal compounds may be used alone or in combination of two or more.

  Examples of weakly basic alkali metal salts include alkali metal carbonates (for example, sodium carbonate, potassium carbonate, rubidium carbonate, cesium carbonate), alkali metal bicarbonates (for example, sodium bicarbonate, potassium bicarbonate, etc.), alkalis Metal phosphates (sodium phosphate, potassium phosphate, etc.), alkali metal carboxylates (sodium acetate, potassium acetate, cesium acetate, etc.), alkali metal sulfates (sodium sulfate, potassium sulfate, cesium sulfate, etc.), alkali metals Examples thereof include halide salts (cesium chloride, cesium iodide, potassium chloride, sodium chloride, etc.) and alkali metal nitrates (sodium nitrate, potassium nitrate, cesium nitrate, etc.). Of these, alkali metal carboxylates, alkali metal carbonates, and alkali metal bicarbonates that can act as salts of weakly acidic strong bases during dissociation are preferably used from the viewpoint that the emulsion is basic, and alkali metal carboxylic acids. A salt is more preferred.

  By using these weakly basic alkali metal compounds to effect pH buffering in the aqueous emulsion polymerization system of the present invention, emulsion polymerization can be stably advanced.

  In the emulsion polymerization, a surfactant, a polymerization initiator, a reducing agent, a buffering agent, a polymerization degree adjusting agent, and the like may be appropriately used as long as the effects of the present invention are not impaired.

  As the surfactant, any of a nonionic surfactant, an anionic surfactant and a cationic surfactant may be used. The nonionic surfactant is not particularly limited. For example, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid ester, polyoxyalkylene alkyl ether, polyoxyethylene derivative, sorbitan fatty acid ester, Examples include polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, glycerin fatty acid ester and the like. The anionic surfactant is not particularly limited, and examples thereof include alkyl sulfates, alkylaryl sulfates, alkyl sulfonates, hydroxyalkanol sulfates, sulfosuccinates, alkyl and alkylaryl polyethoxyalkanol sulfates and phosphates, and the like. Is mentioned. Although it does not specifically limit as a cationic surfactant, For example, an alkylamine salt, a quaternary ammonium salt, polyoxyethylene alkylamine etc. are mentioned. It is preferable that the usage-amount of surfactant is 2 mass% or less with respect to the whole quantity of an ethylenically unsaturated monomer (for example, vinyl acetate). When the usage-amount of surfactant exceeds 2 mass%, since water resistance, warm water resistance, and boiling water resistance may fall, it is unpreferable.

  As the polymerization initiator, a catalyst that forms a radical usually used in emulsion polymerization can be used. Specific examples include hydrogen peroxide, potassium persulfate, ammonium persulfate, tertiary butyl hydroperoxide, azobis- (2-amidinopropane) hydride, lauroyl peroxide, 2,2′-azobisisobutyronitrile, Examples thereof include ketone hydroperoxide. These polymerization initiators can be used as a redox catalyst either alone or in an appropriate combination with a reducing agent.

  Reducing agents include amines, ferrous salts (eg, ferrous sulfate, ferrous ammonium sulfate, ferrous pyrophosphate, etc.), sodium thiosulfate, sodium sulfite, sodium hyposulfite, sodium formaldehyde sulfoxylate, tartaric acid And salts thereof, ascorbic acid and salts thereof, erythorbic acid and salts thereof, and the like. The usage-amount of a catalyst and the reducing agent added as needed is 0.001-10 mass% normally with respect to the whole quantity of an ethylenically unsaturated monomer (for example, vinyl acetate). As a method for adding the catalyst and the reducing agent, the whole amount may be added at the beginning of the polymerization, or a part of the catalyst and the reducing agent may be added as the polymerization proceeds.

  Examples of the buffer include acids such as acetic acid, hydrochloric acid and sulfuric acid; bases such as ammonia, amine cargo soda, cargo potassium and calcium hydroxide; or alkali carbonates, phosphates and acetates. Examples of the polymerization degree regulator include mercaptans and alcohols.

  The concentration of the copolymer resin contained in the aqueous emulsion may be appropriately set according to the use, but is preferably 30 to 60% by mass as a solid content.

  The aqueous emulsion of the present invention can be used for coating, fiber processing and the like, as well as bonding applications such as woodworking and paper processing. The aqueous emulsion obtained by the above method may be used as it is, and if necessary, an antifoaming agent, a pH adjusting agent, a solvent, a pigment, a dye, a preservative, a thickener, a crosslinking agent, a plasticizer, etc. may be added. May be used. In addition, an acid catalyst can be added to cause cross-linking by an acetal bond exchange reaction with the coexisting PVA and improve water resistance. In principle, the acid catalyst is not particularly limited. For example, mineral acids such as hydrochloric acid, sulfuric acid, phosphoric acid, and nitric acid; heteropolyacids such as phosphotungstic acid; paratoluenesulfonic acid, uric acid, barbituric acid, maleic acid, Organic acids such as citraconic acid; isopropyl triisostearoyl titanate, isopropyl tridodecylbenzenesulfonyl titanate, isopropyl tris (dioctyl pyrophosphate) titanate, bis (dioctyl pyrophosphate) oxyacetate titanate, bis (dioctyl pyrophosphate) ethylene titanate, diisopropyl bis (Dioctyl pyrophosphate) titanate, tetraisopropyl bis (dioctyl phosphite) titanate, tetraoctyl bis (ditridecyl phosphite) titanate, tetra (2,2 Diallyloxymethyl-1-butyl) bis (ditridecyl phosphite) titanate, isopropyl tridodecyl benzene sulfonyl titanate, isopropyl tris (dioctyl pyrophosphate) titanate, bis (dioctyl pyrophosphate) oxyacetate titanate, bis (dioctyl pyrophosphate) ethylene Titanate, diisopropylbis (dioctylpyrophosphate) titanate, tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, tetramethyl titanate, titanium acetylacetonate, titanium tetraacetylacetonate, polytitanium acetyl Acetonate, Titanium octylene glycolate, Titanium lactate an Organic titanium compounds such as nium salt, titanium lactate (titanium lactate), titanium triethanolamate, polyhydroxytitanium stearate; zirconium halides such as zirconium oxychloride, hydroxy zirconium chloride, zirconium tetrachloride, zirconium bromide; zirconium sulfate Zirconium salts of mineral acids such as zirconium nitrate; Zirconium salts of organic acids such as zirconyl acetate and zirconyl formate; Zirconium complex salts such as zirconium carbonate ammonium, zirconium zirconium sulfate, ammonium zirconium acetate, sodium zirconium oxalate, zirconium ammonium citrate, etc. Zirconium compounds; aluminum chloride and hydrates thereof; aluminum nitrate and hydrates thereof; aluminum compounds such as aluminum sulfate; Sulfonic acid type strongly acidic ion exchange resins such as Nmberlist (registered trademark), Amberlite (registered trademark) and Dowex (registered trademark); Sulfonic acid type fluorinated alkylene resins such as sulfonated tetrafluoroethylene resin; Mordenite, zeolite In addition, various conventionally known acids such as inorganic solid acids such as activated clay and acid clay can be used, and these acids may be used alone or in combination of two or more. Among these, sulfuric acid, a titanium lactate compound, an aluminum compound, and a solid acid are particularly preferable.

  In order to improve water resistance, a hydrazine compound may be added to the aqueous emulsion of the present invention. The hydrazine compound is not particularly limited, and includes hydrazine, hydrazine hydrard, hydrazine, hydrazine hydrard, hydrazine hydrochloric acid, sulfuric acid, nitric acid, sulfurous acid, phosphoric acid, thiocyanic acid, carbonic acid and other inorganic salts and formic acid, oxalic acid, etc. Organic salts, monosubstituted hydrazines such as methyl, ethyl, propyl, butyl, and allyl, and symmetric disubstituted ones such as 1,1-dimethyl, 1,1-diethyl, 4-n-butyl-metal, etc. Furthermore, as dihydrazine, oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, adipic acid dihydrazide, azelaic acid dihydrazide, sebacic acid dihydrazide, dodecanedioic acid dihydrazide, maleic acid dihydrazide, diglycolic acid dihydrazide, Tartaric acid dihydrazide Various known materials such as malic acid dihydrazide, isophthalic acid dihydrazide, terephthalic acid dihydrazide, dimer acid dihydrazide can be used, and these compounds may be used alone or in combination of two or more. Also good. Among these, adipic acid dihydrazide is particularly preferable. The aqueous emulsion of the present invention may contain a polyvalent isocyanate compound and an amine compound.

  As long as the effects of the present invention are exhibited, the present invention includes embodiments in which the above-described configurations are variously combined within the technical scope of the present invention.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited at all by these Examples. In the examples and comparative examples, “%” and “parts” represent “% by mass” and “parts by mass”, respectively, unless otherwise specified.

  The following method shows the content of alkali metal contained in the aqueous emulsion, emulsion polymerization stability of the aqueous emulsion, adhesiveness (normal, water resistant, warm water resistant, boiling water resistant), heat resistance, and colorability during heat treatment. It was evaluated with.

(1) Measurement of content of alkali metal contained in aqueous emulsion Sodium content was measured with an ICP emission analyzer (manufactured by Nippon Jarrell Ash, model number: IRIS-AP).

(2) Evaluation of emulsion polymerization stability 500 g of the aqueous emulsion obtained in Examples and Comparative Examples was filtered through a 60-mesh wire mesh, and the filtration residue was weighed and evaluated as follows.
○: Filtration residue is 1.0% or less Δ: Filtration residue is greater than 1.0% ×: Polymerization becomes unstable and cannot be filtered due to coarse particles

(3) Adhesive evaluation (evaluation of normal, water resistance, warm water resistance, boiling water resistance)
[Adhesion conditions]
Substrate: Tsuga / Tsuga (Masa eyes)
Application amount: 150 g / m ² (double-sided application)
Clamping conditions: 20 ° C., 24 hours, pressure 10 kg / cm ²
〔Measurement condition〕
The compression shear bond strength according to JIS K 6852 (1994) was measured.
Normal state: Measured as it was after curing at 20 ° C. for 7 days.
Water resistance: After being immersed in water at 30 ° C. for 3 hours, the measurement was performed in a wet state.
Hot water resistance: Measured in a wet state after being immersed in water at 60 ° C. for 3 hours.
Boiling water resistance: After curing at 20 ° C. for 7 days, the test piece is immersed in boiling water for 4 hours, then dried in air at 60 ° C. for 20 hours, further immersed in boiling water for 4 hours, and then in room temperature water. It was soaked until cooled and measured in the wet state.

(4) Heat resistance evaluation A sample similar to that for the adhesive evaluation was prepared and processed under the following conditions to measure the compression shear adhesive strength.
〔Measurement condition〕
Heat resistance: After curing at 20 ° C. for 7 days, after heating in a thermostatic bath at 105 ° C. for 5 hours, measurement was performed while still hot.

(5) Evaluation of anti-coloring property of film The aqueous emulsions obtained in Examples and Comparative Examples were cast on a PET film under the conditions of 20 ° C. and 65% RH. Then, it was made to dry by leaving still for 7 days, and it peeled from PET film, and obtained the 500-micrometer dry film. The film was fixed to a stainless steel metal frame (20 cm × 20 cm and 1 cm wide metal frame) with a clip and heat-treated at 120 ° C. for 3 hours in a gear oven. The street was evaluated.
○: Not colored Δ: Slightly colored ×: Colored yellow

Example 1
(Synthesis of Em-1)
In a 1 liter glass polymerization vessel equipped with a reflux condenser, a dropping funnel, a thermometer, and a nitrogen inlet, 300 g of ion exchange water, “PVA-117” (manufactured by Kuraray Co., Ltd., saponification degree 98.5 mol%, average polymerization) 1700) 19.5 g was charged and stirred at 95 ° C. for 2 hours to completely dissolve. Further, 0.2 g of sodium acetate (NaOAc) was added and mixed and dissolved. Next, this PVA aqueous solution was cooled, purged with nitrogen, heated to 60 ° C. while stirring at 200 rpm, and then 4.4 g of 10% aqueous solution of tartaric acid and 3 g of 5% aqueous hydrogen peroxide (total amount of initial charge) After adding 0.15) by mole ratio to the body, 26 g of vinyl acetate and 0.26 g of acrolein dimethyl acetal were charged to initiate polymerization. After 30 minutes from the start of polymerization, the completion of the initial polymerization was confirmed (the remaining amount of vinyl acetate was less than 1%). After adding shot of 0.9 g of 10% aqueous solution of tartaric acid and 3 g of 5% aqueous hydrogen peroxide, 234 g of vinyl acetate and 2.34 g of acrolein dimethyl acetal were continuously added over 2 hours, and the polymerization temperature was maintained at 80 ° C. Polymerization was completed, and a polyvinyl acetate emulsion having a solid content of 47.2% (1% by mass of acrolein dimethyl acetal based on the total amount of vinyl acetate) was obtained. 5 parts by mass of phenoxyethanol as a plasticizer was added to and mixed with 100 parts by mass (solid content) of the emulsion. When the polymerization stability of the obtained emulsion (Em-1) was evaluated, the filtration residue was 1.0% or less. At this time, the content of sodium atoms contained in Em-1 was 300 ppm with respect to the total amount of the emulsion.

(Em-1 evaluation)
Adhesion (normal, water resistant, warm water resistant, boiling water resistant) according to the above method using 100 parts by weight of the aqueous emulsion Em-1 with 1 part by weight of 10% sulfuric acid added as a pH adjuster Evaluation, heat resistance evaluation, and coloration resistance of the film were evaluated. The results are shown in Table 2.

(Example 2)
(Synthesis of Em-2)
In a 1 liter glass polymerization vessel equipped with a reflux condenser, a dropping funnel, a thermometer, and a nitrogen blowing port, ion-exchanged water 330 g, “PVA-217” (manufactured by Kuraray Co., Ltd., saponification degree 88.0 mol%, average polymerization) 1700) 17.4 g was charged and stirred at 95 ° C. for 2 hours to completely dissolve. Further, 0.2 g of sodium acetate (NaOAc) was added and mixed and dissolved. Next, this PVA aqueous solution was cooled, purged with nitrogen, heated to 60 ° C. while stirring at 200 rpm, 3.6 g of 10% aqueous solution of tartaric acid and 2.5 g of 5% aqueous hydrogen peroxide (total amount of initial charge) After adding 0.015) in a molar ratio with respect to each monomer, 23 g of vinyl acetate and 0.23 g of acrolein dimethyl acetal were charged and polymerization was started. After 30 minutes from the start of polymerization, the completion of the initial polymerization was confirmed (the remaining amount of vinyl acetate was less than 1%). Shot addition of 0.74g of 10% aqueous tartaric acid solution and 2.47g of 5% hydrogen peroxide solution, followed by continuous addition of 207g vinyl acetate and 2.07g acrolein dimethyl acetal over 2 hours to maintain the polymerization temperature at 80 ° C Thus, the polymerization was completed, and a polyvinyl acetate emulsion having a solid concentration of 42.0% (acrolein dimethyl acetal 1% by mass with respect to the total amount of vinyl acetate) was obtained. 5 parts by mass of phenoxyethanol as a plasticizer was added to and mixed with 100 parts by mass (solid content) of the emulsion. When the polymerization stability of the obtained emulsion (Em-2) was evaluated, the filtration residue was 1.0% or less. At this time, the content of sodium atoms contained in Em-2 was 300 ppm with respect to the total amount of the emulsion.

(Em-2 evaluation)
Adhesion (normal, water resistant, warm water resistant, boiling water resistant) according to the above method using 100 parts by weight of the aqueous emulsion Em-2 with 1 part by weight of 10% sulfuric acid added as a pH adjuster Evaluation, heat resistance evaluation, and coloration resistance of the film were evaluated. The results are shown in Table 2.

(Example 3)
(Synthesis of Em-3)
In a 1 liter glass polymerization vessel equipped with a reflux condenser, a dropping funnel, a thermometer, and a nitrogen inlet, 300 g of ion-exchanged water, ethylene-modified PVA (polymerization degree 1700, saponification degree 95 mol%, ethylene modification amount 5 mol%) 19.5 g was charged and stirred at 95 ° C. for 2 hours to completely dissolve. Further, 0.2 g of sodium acetate (NaOAc) was added and mixed and dissolved. Next, this PVA aqueous solution was cooled, purged with nitrogen, heated to 60 ° C. while stirring at 200 rpm, and then 4.4 g of 10% aqueous solution of tartaric acid and 3 g of 5% aqueous hydrogen peroxide (total amount of initial charge) After adding 0.15) by mole ratio to the body, 26 g of vinyl acetate and 0.26 g of acrolein dimethyl acetal were charged to initiate polymerization. After 30 minutes from the start of polymerization, the completion of the initial polymerization was confirmed (the remaining amount of vinyl acetate was less than 1%). After adding shot of 0.9 g of 10% aqueous solution of tartaric acid and 3 g of 5% aqueous hydrogen peroxide, 234 g of vinyl acetate and 2.34 g of acrolein dimethyl acetal were continuously added over 2 hours, and the polymerization temperature was maintained at 80 ° C. Polymerization was completed, and a polyvinyl acetate emulsion having a solid content of 47.2% (1% by mass of acrolein dimethyl acetal based on the total amount of vinyl acetate) was obtained. 5 parts by mass of phenoxyethanol as a plasticizer was added to and mixed with 100 parts by mass (solid content) of the emulsion. When the polymerization stability of the obtained emulsion (Em-3) was evaluated, the filtration residue was 1.0% or less. At this time, the content of sodium atoms contained in Em-3 was 300 ppm with respect to the total amount of the emulsion.

(Em-3 evaluation)
Using 100 parts by weight of the aqueous emulsion Em-3 with 1 part by weight of 10% sulfuric acid added as a pH adjuster, according to the above method, adhesion (normal state, water resistance, warm water resistance, boiling water resistance) Evaluation, heat resistance evaluation, and coloration resistance of the film were evaluated. The results are shown in Table 2.

Example 4
The amount of acrolein dimethyl acetal charged was changed to 2% by mass, the amount of sodium acetate added was adjusted, and the aqueous emulsion (Em- 4) was obtained. Table 1 shows the content of sodium atoms contained in Em-4 and the evaluation results of the polymerization stability. Using 100 parts by weight of the aqueous emulsion Em-4 with 1 part by weight of 10% sulfuric acid added as a pH adjuster, according to the above method, adhesion (normal state, water resistance, warm water resistance, boiling water resistance) Evaluation, heat resistance evaluation, and coloration resistance of the film were evaluated. The results are shown in Table 2.

(Example 5)
An aqueous emulsion (Em-5) was obtained in the same manner as in Example 1 except that 5% by mass of acrolein diethyl acetal was used instead of acrolein dimethyl acetal. Table 1 shows the content of sodium atoms contained in Em-5 and the evaluation results of the polymerization stability. Using 100 parts by weight of the aqueous emulsion Em-5 with 1 part by weight of 10% sulfuric acid added as a pH adjuster, according to the above method, adhesion (normal state, water resistance, warm water resistance, boiling water resistance) Evaluation, heat resistance evaluation, and coloration resistance of the film were evaluated. The results are shown in Table 2.

(Example 6)
An aqueous emulsion (Em-6) was obtained in the same manner as in Example 1 except that 8% by mass of N-2,2-dimethoxyethyl methacrylamide was used instead of acrolein dimethyl acetal. Table 1 shows the content of sodium atoms contained in Em-6 and the evaluation results of the polymerization stability. Using 100 parts by weight of the aqueous emulsion Em-6 with 1 part by weight of 10% sulfuric acid added as a pH adjuster, according to the above method, adhesion (normal state, water resistance, warm water resistance, boiling water resistance) Evaluation, heat resistance evaluation, and coloration resistance of the film were evaluated. The results are shown in Table 2.

(Example 7)
An aqueous emulsion (Em-7) was obtained in the same manner as in Example 3 except that 1% by mass of 2- (6-heptenyl) -1,3-dioxolane was used instead of acrolein dimethyl acetal. Table 1 shows the content of sodium atoms contained in Em-7 and the evaluation results of the polymerization stability. Using 100 parts by weight of the aqueous emulsion Em-7 with 1 part by weight of 10% sulfuric acid added as a pH adjuster, according to the above method, adhesion (normal state, water resistance, warm water resistance, boiling water resistance) Evaluation, heat resistance evaluation, and coloration resistance of the film were evaluated. The results are shown in Table 2.

(Example 8)
An aqueous emulsion (Em-8) was obtained in the same manner as in Example 3 except that 1% by mass of 2- (2-methyl-2-propenyl) -1,3-dioxolane was used instead of acrolein dimethyl acetal. Table 1 shows the content of sodium atoms contained in Em-8 and the evaluation results of the polymerization stability. Using 100 parts by weight of the aqueous emulsion Em-8 with 1 part by weight of 10% sulfuric acid added as a pH adjuster, according to the above method, adhesion (normal state, water resistance, warm water resistance, boiling water resistance) Evaluation, heat resistance evaluation, and coloration resistance of the film were evaluated. The results are shown in Table 2.

Example 9
An aqueous emulsion (Em-9) was obtained in the same manner as in Example 1 except that 11% by mass of arylidene diacetate was used instead of acrolein dimethyl acetal. Table 1 shows the content of sodium atoms contained in Em-9 and the evaluation results of the polymerization stability. Using 100 parts by weight of the aqueous emulsion Em-9 with 1 part by weight of 10% sulfuric acid added as a pH adjuster, according to the above method, adhesion (normal state, water resistance, warm water resistance, boiling water resistance) Evaluation, heat resistance evaluation, and coloration resistance of the film were evaluated. The results are shown in Table 2.

(Example 10)
(Synthesis of Em-10)
In a 1.5 liter stainless steel autoclave equipped with an irrigation type stirrer, 360 g of ion exchange water, polyvinyl alcohol “PVA-205” (manufactured by Kuraray Co., Ltd., saponification degree 88 mol%, average polymerization degree 500) 24.3 g And 2.9 g of “PVA-217” (manufactured by Kuraray Co., Ltd., saponification degree: 88 mol%, average polymerization degree: 1700) was stirred at 95 ° C. for 2 hours and completely dissolved. Further, 0.04 g of sodium acetate (NaOAc) was added. Next, 350 g of vinyl acetate and 7.29 g of acrolein dimethyl acetal were charged, and the air in the autoclave was sufficiently replaced with ethylene. Subsequently, 19.5 g of a 10% ascorbic acid aqueous solution was charged, and under stirring, the polymerization temperature was increased to 60 ° C., and the ethylene pressure was increased to 5.0 MPa. 100 g of 1% hydrogen peroxide solution was uniformly added over 8 hours, and 117 g of vinyl acetate and 2.44 g of acrolein dimethyl acetal were uniformly added over 6 hours. The ethylene pressure was maintained at 5.0 MPa until the end of the addition of vinyl acetate and acrolein dimethyl acetal. It cooled after completion | finish of catalyst addition, the antifoamer and the pH adjuster were added, and the aqueous emulsion was obtained. When the polymerization stability of the obtained emulsion (Em-10) was evaluated, the filtration residue was 1.0% or less. At this time, the content of sodium atoms contained in Em-10 was 300 ppm with respect to the total amount of the emulsion.

(Em-10 evaluation)
Using 100 parts by weight of the aqueous emulsion Em-10 with 1 part by weight of 10% sulfuric acid added as a pH adjuster, according to the above method, adhesion (normal state, water resistance, warm water resistance, boiling water resistance) Evaluation, heat resistance evaluation, and coloration resistance of the film were evaluated. The results are shown in Table 2.

(Examples 11-14)
Aqueous emulsions (Em-11 to Em-14) were obtained in the same manner as in Example 1 except that the amount of sodium acetate to be added was adjusted and the content of sodium atoms was changed to the contents shown in Table 2. Table 1 shows the content of sodium atoms contained in Em-11 to Em-14 and the evaluation results of the polymerization stability. Evaluation of adhesiveness (normal, water resistant, warm water resistant, boiling water resistant) according to the above method using 100 parts by weight of each aqueous emulsion with 1 part by weight of 10% sulfuric acid added as a pH adjuster , Heat resistance evaluation, and color resistance of the film were evaluated. The results are shown in Table 2.

(Comparative Example 1)
(Synthesis of Em-15)
In a 1 liter glass polymerization vessel equipped with a reflux condenser, a dropping funnel, a thermometer, and a nitrogen inlet, 300 g of ion exchange water, “PVA-117” (manufactured by Kuraray Co., Ltd., saponification degree 98.5 mol%, average polymerization) 1700) 19.5 g was charged and stirred at 95 ° C. for 2 hours to completely dissolve. Further, 0.2 g of sodium acetate (NaOAc) was added and mixed and dissolved. Next, this PVA aqueous solution was cooled, purged with nitrogen, heated to 60 ° C. while stirring at 200 rpm, and then 4.4 g of 10% aqueous solution of tartaric acid and 3 g of 5% aqueous hydrogen peroxide (total amount of initial charge) After adding 0.15) by mole ratio to the body, 26 g of vinyl acetate was charged and polymerization was started. After 30 minutes from the start of polymerization, the completion of the initial polymerization was confirmed (the remaining amount of vinyl acetate was less than 1%). Shot addition of 0.9 g of 10% aqueous tartaric acid solution and 3 g of 5% aqueous hydrogen peroxide followed by continuous addition of 234 g vinyl acetate and 2.6 g N-methylol acrylamide over 2 hours to maintain the polymerization temperature at 80 ° C. As a result, polymerization was completed, and a polyvinyl acetate emulsion having a solid content of 47.2% (containing 1% by mass of N-methylolacrylamide with respect to the total amount of vinyl acetate 100) was obtained. 5 parts by mass of phenoxyethanol as a plasticizer was added to and mixed with 100 parts by mass (solid content) of the emulsion. When the polymerization stability of the obtained emulsion (Em-15) was evaluated, the filtration residue was 1.0% or less. At this time, the content of sodium atoms contained in Em-15 was 300 ppm with respect to the total amount of the emulsion.

(Em-15 evaluation)
Using 100 parts by weight of the aqueous emulsion Em-15 with 1 part by weight of 10% sulfuric acid added as a pH adjuster, according to the above method, adhesion (normal state, water resistance, warm water resistance, boiling water resistance) Evaluation, heat resistance evaluation, and coloration resistance of the film were evaluated. The results are shown in Table 2.

(Comparative Example 2)
An aqueous emulsion (Em-16) was obtained in the same manner as in Example 1 except that acrolein dimethyl acetal was not used. Table 1 shows the content of sodium atoms contained in Em-16 and the evaluation results of the polymerization stability. Using 100 parts by weight of the aqueous emulsion Em-16 with 1 part by weight of 10% sulfuric acid added as a pH adjuster, according to the above method, adhesion (normal state, water resistance, warm water resistance, boiling water resistance) Evaluation, heat resistance evaluation, and coloration resistance of the film were evaluated. The results are shown in Table 2.

(Comparative Example 3)
An aqueous emulsion (Em-17) was obtained in the same manner as in Example 2 except that acrolein dimethyl acetal was not used. Table 1 shows the content of sodium atoms contained in Em-17 and the evaluation results of the polymerization stability. Using 100 parts by weight of the aqueous emulsion Em-17 with 1 part by weight of 10% sulfuric acid added as a pH adjuster, according to the above method, adhesion (normal, water resistant, warm water resistant, boiling water resistant) Evaluation, heat resistance evaluation, and coloration resistance of the film were evaluated. The results are shown in Table 2.

(Comparative Example 4)
An aqueous emulsion (Em-18) was obtained in the same manner as in Example 3 except that acrolein dimethyl acetal was not used. Table 1 shows the content of sodium atoms contained in Em-18 and the evaluation results of the polymerization stability. Using 100 parts by weight of the aqueous emulsion Em-18 with 1 part by weight of 10% sulfuric acid added as a pH adjuster, according to the above method, adhesion (normal state, water resistance, warm water resistance, boiling water resistance) Evaluation, heat resistance evaluation, and coloration resistance of the film were evaluated. The results are shown in Table 2.

(Comparative Example 5)
(Synthesis of Em-19)
In a 1 liter glass polymerization vessel equipped with a reflux condenser, a dropping funnel, a thermometer, and a nitrogen inlet, 300 g of ion-exchanged water, ethylene-modified PVA (polymerization degree 1700, saponification degree 95 mol%, ethylene modification amount 5 mol%) 15.2 g was charged and stirred at 95 ° C. for 2 hours to completely dissolve. Next, this PVA aqueous solution was cooled, and 21.7 g of a 20% aqueous solution of polyacrylic acid (trade name Jurimer AC20H (manufactured by Nippon Pure Chemical Co., Ltd.)) was added. Further, 0.2 g of sodium acetate (NaOAc) was added. This aqueous solution was purged with nitrogen, heated to 60 ° C. while stirring at 200 rpm, and then 4.4 g of a 10% aqueous solution of tartaric acid and 3 g of 5% hydrogen peroxide (molar ratio to the total amount of monomers initially charged). And 0.015) of each was added by shot, and then 26 g of vinyl acetate was added to initiate polymerization. After 30 minutes from the start of polymerization, the completion of the initial polymerization was confirmed (the remaining amount of vinyl acetate was less than 1%). After adding 0.9 g of 10% aqueous solution of tartaric acid and 3 g of 5% hydrogen peroxide solution, 234 g of vinyl acetate is continuously added over 2 hours, and the polymerization temperature is maintained at 80 ° C. to complete the polymerization. A polyvinyl acetate emulsion having a concentration of 47.2% was obtained. 5 parts by mass of phenoxyethanol as a plasticizer was added to and mixed with 100 parts by mass (solid content) of the emulsion. When the polymerization stability of the obtained emulsion (Em-19) was evaluated, the filtration residue was 1.0% or less. At this time, the content of sodium atoms contained in Em-19 was 300 ppm with respect to the total amount of the emulsion.

(Em-19 evaluation)
Using 100 parts by weight of the aqueous emulsion Em-19 with 1 part by weight of 10% sulfuric acid added as a pH adjuster, according to the above method, adhesion (normal state, water resistance, warm water resistance, boiling water resistance) Evaluation, heat resistance evaluation, and coloration resistance of the film were evaluated. The results are shown in Table 2.

(Comparative Example 6)
An emulsion was prepared according to the reference number 5.2 of Example 5 of JP-T-2003-517499. The obtained emulsion had 45% of methyl methacrylate / butyl acrylate / methacrylamide amidaldehyde dimethyl = 33 / 61.3 / 5.7 copolymer particles. The obtained emulsion was adjusted to pH 2 with 10% hydrochloric acid and evaluated for heat resistance. As a result, the adhesive strength was 7 kg / cm ² and the heat resistance was insufficient.

  The aqueous emulsion of the present invention is excellent in heat resistance, excellent in water resistance, warm water resistance, and boiling water resistance, and can be used for coating, fiber processing, etc., as well as adhesive applications such as woodworking and paper processing.

Claims (7)

Obtained by copolymerizing an ethylenically unsaturated monomer (B) and a monomer (C) represented by the following formula (I) or (II) in the presence of the polyvinyl alcohol resin (A). An aqueous emulsion characterized by that.

(In the formula, R ¹ is a hydrogen atom, a linear alkyl group having 1 to 8 carbon atoms or —CH ₂ —COOM, where M is a hydrogen atom, a methyl group, an alkali metal or an ammonium group; ² and R ³ are the same or different and are an alkyl group having 1 to 8 carbon atoms or an alkylcarbonyl group having 2 to 8 carbon atoms, R ⁴ is a hydrogen atom or —COOM, where M is a hydrogen atom, methyl X is — (CH ₂ ) _n —, —CO—NH— (CH ₂ ) _n —, —NH—CO— (CH ₂ ) _n —, —CO— (CH ₂ ) _N —, —CO—O— (CH ₂ ) _n —, —O—CO— (CH ₂ ) _n —, —NR ⁵ —CO— (CH ₂ ) _n —, or —CO—NR ⁵ — (CH ₂ ) _n- , wherein R ⁵ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and n is an integer of 0 to 8. is there.)

(Wherein R ¹ , R ⁴ and X have the same meaning as described above, R ⁶ is — (CH ₂ —CH ₂ ) _m —, and m is an integer of 1 to 3). In the formula (I) or (II), X is - (CH _{2) n} - an aqueous emulsion of claim 1.   The aqueous emulsion according to claim 1 or 2, wherein the ethylenically unsaturated monomer (B) is at least one selected from the group consisting of vinyl ester monomers and diene monomers. .   The amount of the monomer (C) represented by the formula (I) or (II) is 0.01 to 10% by mass with respect to the ethylenically unsaturated monomer (B). The aqueous emulsion according to any one of claims 1 to 3.   The aqueous emulsion according to any one of claims 1 to 4, comprising 100 to 15000 ppm of an alkali metal compound (in terms of alkali metal) with respect to the total weight of the emulsion (in terms of solid). In the presence of the polyvinyl alcohol-based resin (A), the method includes a step of copolymerizing the ethylenically unsaturated monomer (B) and the monomer (C) represented by the following formula (I) or (II). A method for producing an aqueous emulsion.

(In the formula, R ¹ is a hydrogen atom, a linear alkyl group having 1 to 8 carbon atoms or —CH ₂ —COOM, where M is a hydrogen atom, a methyl group, an alkali metal or an ammonium group; ² and R ³ are the same or different and are an alkyl group having 1 to 8 carbon atoms or an alkylcarbonyl group having 2 to 8 carbon atoms, R ⁴ is a hydrogen atom or —COOM, where M is a hydrogen atom, methyl X is — (CH ₂ ) _n —, —CO—NH— (CH ₂ ) _n —, —NH—CO— (CH ₂ ) _n —, —CO— (CH ₂ ) _N —, —CO—O— (CH ₂ ) _n —, —O—CO— (CH ₂ ) _n —, —NR ⁵ —CO— (CH ₂ ) _n —, or —CO—NR ⁵ — (CH ₂ ) _n- , wherein R ⁵ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and n is an integer of 0 to 8. is there.)

(Wherein R ¹ , R ⁴ and X have the same meaning as described above, R ⁶ is — (CH ₂ —CH ₂ ) _m —, and m is an integer of 1 to 3).   The amount of the monomer (C) represented by the formula (I) or (II) is 0.01 to 10% by mass with respect to the ethylenically unsaturated monomer (B). The method for producing an aqueous emulsion according to claim 6.