JP2002322335A - Aqueous emulsion composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an aqueous emulsion composition excellent in viscosity stability during standing, water resistance and adhesion in boiling water. SOLUTION: This aqueous emulsion composition is composed of an aqueous emulsion (A) and a hydrazine compound (B). In the emulsion (A), a vinyl alcohol-based polymer containing 1-20 mol% of an α-olefin unit having 4 or less carbons in the molecule and having a degree of saponification of 90 mol% or more is a dispersant and a polymer containing 0.1-10 pts.wt. of a monomer unit having a carbonyl group in the molecule per 100 pts.wt. of a vinyl ester monomer unit is a dispersoid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aqueous emulsion composition, and more particularly to an aqueous emulsion composition having excellent water resistance, boiling water resistance and storage stability.

[0002]

2. Description of the Related Art Conventionally, polyvinyl alcohol (hereinafter referred to as P
VA) is widely used as a protective colloid for emulsion polymerization of ethylenically unsaturated monomers, particularly vinyl ester monomers represented by vinyl acetate, and is used as a protective colloid. Vinyl ester aqueous emulsion obtained by emulsion polymerization is used for various adhesives for paper, woodworking and plastics, various binders for impregnated paper and non-woven products, admixtures, jointing materials, paints, paper processing And widely used in fields such as fiber processing. Such an aqueous emulsion generally has a low viscosity by adjusting the degree of saponification of the PVA-based polymer, has a viscosity close to a Newtonian flow, and has a relatively good water resistance. Since it has a high viscosity and relatively low temperature dependence of emulsion viscosity, it has been awarded for various uses. However, some of the aqueous emulsions lack fluidity (high-speed coating properties), have poor water resistance, have a large temperature dependence of emulsion viscosity, and have a marked increase in emulsion viscosity at low temperatures. It is known that it has drawbacks and that these properties largely depend on the PVA-based polymer used in the emulsion polymerization.

That is, PV as a dispersant for emulsion polymerization
A-type polymers generally include so-called "fully saponified PVA" having a saponification degree of about 98 mol% and "partially saponified PVA" having a saponification degree of about 88 mol%. Although the fluidity (high-speed coating property) is good, there is a disadvantage that the viscosity of the emulsion at the time of leaving at low temperature is remarkably increased and gelation is easily caused. On the other hand, when the latter PVA-based polymer is used, the emulsion has an improved viscosity at low temperatures and a tendency to gel at low temperatures, but has a disadvantage of poor water resistance. In order to improve such drawbacks, both PVA polymers are used in combination, and PVA polymers having an intermediate saponification degree between the two are used. Sex was not satisfied at the same time. Then, a vinyl alcohol-based polymer containing an ethylene unit was proposed, and the water resistance and the low-temperature storage stability were greatly improved. However, even if it has an ethylene unit, the requirement cannot be completely satisfied in an application requiring strict water resistance, for example, an application in which a boiling water immersion test must be cleared because of PVA. Was the current situation.

[0004]

SUMMARY OF THE INVENTION Under the above circumstances, the present invention provides an aqueous emulsion composition which is excellent in both water resistance and storage stability and furthermore has excellent boiling water adhesion. It is the purpose.

[0005]

Means for Solving the Problems The present inventors have conducted intensive studies to develop an aqueous emulsion composition having the above-mentioned preferable properties.
It contains 1 to 20 mol% of olefin units and has a saponification degree of 90.
Mol% or more of a vinyl alcohol polymer as a dispersant,
Aqueous emulsion (A) containing a polymer containing 0.1 to 10 parts by weight of a monomer unit having a carbonyl group in a molecule with respect to 100 parts by weight of a vinyl ester-based monomer unit, and a hydrazine compound (A) The present inventors have found that the aqueous emulsion composition comprising B) satisfies the object, and have completed the present invention.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION An α-olefin unit having 4 or less carbon atoms in a molecule used as a dispersant for the aqueous emulsion (A) used in the aqueous emulsion composition of the present invention has one to one.
A vinyl alcohol polymer containing 20 mol% and having a degree of saponification of 90 mol% or more can be obtained by saponifying a copolymer of a vinyl ester and an α-olefin having 4 or less carbon atoms. Here, the α-olefin unit having 4 or less carbon atoms includes ethylene, propylene, butylene, and isobutylene units, and ethylene units are preferable.

Examples of the vinyl ester include vinyl formate, vinyl acetate, vinyl propionate and vinyl pivalate. Vinyl acetate is economically preferable.

The content of the α-olefin unit having 4 or less carbon atoms must be 1 to 20 mol%,
Preferably it is 2 to 15%, more preferably 3 to 10%. When the content of α-olefin units having 4 or less carbon atoms is 1
If it is less than 20 mol%, an aqueous emulsion satisfying the above-mentioned water resistance and storage stability at the same time cannot be obtained.
If the ratio exceeds the above range, there is a concern that the water solubility decreases and a stable aqueous emulsion cannot be obtained.

[0009] Further, the molecule used for the dispersant contains 1 to 20 mol% of α-olefin units having 4 or less carbon atoms,
The vinyl alcohol polymer having a saponification degree of 90 mol% or more may be a copolymer of an ethylenically unsaturated monomer copolymerizable within a range not to impair the effects of the present invention. Such ethylenically unsaturated monomers include, for example, acrylic acid, methacrylic acid, fumaric acid, (anhydride) maleic acid,
Itaconic acid, acrylonitrile, methacrylonitrile,
Acrylamide, methacrylamide, trimethyl- (3
-Acrylamido-3-dimethylpropyl) -ammonium chloride, acrylamido-2-methylpropanesulfonic acid and its sodium salt, ethyl vinyl ether, butyl vinyl ether, N-vinyl pyrrolidone, vinyl chloride, vinyl bromide, vinyl fluoride, vinylidene chloride, Examples include vinylidene fluoride, tetrafluoroethylene, sodium vinyl sulfonate, sodium allyl sulfonate, and the like. Further, in the presence of a thiol compound such as thiolacetic acid or mercaptopropionic acid, a terminal modification obtained by copolymerizing a vinyl ester monomer such as vinyl acetate with an olefin having 4 or less carbon atoms and saponifying it. Things can also be used.

The vinyl alcohol polymer having 1 to 20 mol% of α-olefin units in the molecule used as a dispersant for the aqueous emulsion of the present invention and having a saponification degree of 90 mol% or more has a saponification degree of 90 mol% or more. And more preferably at least 92 mol%, further preferably at least 93 mol%. When the degree of saponification is less than 90 mol%, an aqueous emulsion composition having excellent water resistance cannot be obtained. The degree of polymerization of the vinyl alcohol polymer is 10
The range is preferably from 0 to 8000, and more preferably from 300 to 3000. When the degree of polymerization is less than 100, the characteristics as a PVA protective colloid are not exhibited, and when it exceeds 8,000, there is a problem in industrial production of the PVA-based polymer.

The vinyl ester monomer constituting the dispersoid in the aqueous emulsion constituting the aqueous emulsion composition of the present invention includes vinyl esters such as vinyl formate, vinyl acetate, vinyl propionate and vinyl versatate. However, vinyl acetate is preferably used.

In the present invention, it is essential to use a monomer having a carbonyl group in the molecule. Examples of the monomer having a carbonyl group in the molecule include diacetone acrylamide, diacetone acrylate, diacetone methacrylate, allyl acetoacetate, vinyl methyl ketone, vinyl ethyl ketone, among which diacetone acrylamide or allyl acetoacetate is included. It is preferably used.

In the present invention, the monomer unit having a carbonyl group in the molecule is a vinyl ester monomer unit.
It is important to contain 0.1 to 10 parts by weight with respect to 0 parts by weight, preferably 0.2 to 5 parts by weight, more preferably 0.25 to 3 parts by weight. When the amount of the monomer unit having a carbonyl group is less than 0.1 part by weight, the water resistance and the adhesive strength against boiling water are insufficient, and when it exceeds 10 parts by weight, the polymerization stability may be reduced.

In the present invention, other copolymerizable ethylenically unsaturated monomers can be used as long as the effects of the present invention are not impaired. Examples of such ethylenically unsaturated monomers include olefins such as ethylene, propylene and isobutylene, halogenated olefins such as vinyl chloride, vinyl fluoride, vinylidene chloride and vinylidene fluoride, acrylic acid, methacrylic acid and methyl acrylate. Acrylates such as ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, 2-hydroxyethyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, methacryl Methacrylic acid esters such as dodecyl acid, 2-hydroxyethyl methacrylate, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate and quaternary products thereof, furthermore, acrylamide, methacrylic acid Riruamido, N- methylolacrylamide, N, N- dimethylacrylamide, acrylamide-based monomers such as acrylamido-2-methylpropanesulfonic acid and its sodium salt, styrene, alpha-methyl styrene, p
-Styrene sulfonic acid and styrene monomers such as sodium and potassium salts, other N-vinylpyrrolidone and the like, and diene monomers such as butadiene, isoprene and chloroprene. Used as

The aqueous emulsion constituting the aqueous emulsion composition of the present invention is formed of the above-mentioned vinyl alcohol polymer having an α-olefin unit having 4 or less carbon atoms (hereinafter sometimes abbreviated as α-olefin-modified PVA). Using an aqueous solution as a dispersant, in the presence of a conventionally known polymerization initiator, a method of emulsion polymerization by temporarily or continuously adding the vinyl ester monomer and a monomer having a carbonyl group, A method in which an ester-based monomer and a monomer having a carbonyl group are emulsified in advance using an aqueous solution of an α-olefin-modified PVA, and then continuously added to the polymerization reaction system to carry out emulsion polymerization. A method in which the whole amount of the monomer having a carbonyl group is charged into the vinyl ester-based monomer to be charged and emulsion polymerization is carried out.
The amount of the α-olefin-modified PVA is not particularly limited, but is preferably 1 to 100 parts by weight of a polymer (dispersoid) of a vinyl ester monomer and a monomer having a carbonyl group. 30 parts by weight, more preferably 2-2
The range is 0 parts by weight. When the amount is less than 1 part by weight or more than 30 parts by weight, the polymerization stability may be reduced, and the initial adhesive strength and the water-resistant adhesive strength may be reduced. As the aqueous emulsion used in the present invention, the aqueous emulsion obtained by the above method can be used as it is,
If necessary, various conventionally known emulsions can be used in combination as long as the effects of the present invention are not impaired. Also,
As the dispersant in the aqueous emulsion used in the present invention, α-olefin-modified PVA is used. If necessary, conventionally known anionic, nonionic or cationic surfactants and other PVA and the like can be used. PVA
A system polymer, hydroxyethyl cellulose and the like can be used in combination.

The hydrazine compound (B) used in the present invention is not particularly restricted but includes hydrazine, hydrazine hydrate, monohydrate or salt of hydrazine, phenylhydrazine, methylhydrazine, ethylhydrazine, n-propylhydrazine, n-butylhydrazine,
Ethylene-1,2-dihydrazine, propylene-1,3
Aromatic or aliphatic hydrazines such as dihydrazine, butylene-1,4-dihydrazine and salts thereof, benzoic hydrazide, formic hydrazide, acetic hydrazide, propionic hydrazide, n-butyric hydrazide, isobutyric hydrazide, n-k Monocarboxylic acid hydrazide such as valeric acid hydrazide, isovaleric acid hydrazide, pivalic acid hydrazide, oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide,
Dicarboxylic acid dihydrazide such as glutaric acid dihydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, maleic acid dihydrazide, fumaric acid dihydrazide, itaconic acid dihydrazide and the like, and carbonic acid dihydrazine.

In the aqueous emulsion composition of the present invention, the amount of the hydrazine compound (B) to be added to the aqueous emulsion is not particularly limited, but is 0.01 to 100 parts by weight (solid content) of the aqueous emulsion (A). ~ 1
0 parts by weight is preferable, 0.02 to 7 parts by weight, and more preferably 0.03 to 5 parts by weight. When the blending ratio of the hydrazine compound (B) is less than 0.01 part by weight, the water resistance and the boiling water resistance are low, and when it exceeds 10 parts by weight, the viscosity stability of the aqueous emulsion composition may decrease. .

In the present invention, the addition of calcium carbonate further improves the water-resistant adhesive property. The amount of calcium carbonate is not particularly limited, but is preferably 1 to 200 parts by weight based on 100 parts by weight (solid content) of the aqueous emulsion.
Parts by weight, more preferably 3 to 150 parts by weight, even more preferably 5 to 130 parts by weight.

The aqueous emulsion composition of the present invention may contain various organic solvents such as toluene, perchrene, dichlorobenzene and trichlorobenzene in order to adjust the drying property, setting property, viscosity, film forming property and the like, if necessary. , Starch, modified starch, oxidized starch, sodium alginate,
Water-soluble polymers such as carboxymethylcellulose, methylcellulose, hydroxymethylcellulose, maleic anhydride / isobutene copolymer, maleic anhydride / styrene copolymer, maleic anhydride / methylvinyl ether copolymer, polyvinyl alcohol, and urea / formalin resin, Thermosetting resins such as urea / melamine / holimarin resins, phenol / formalin resins, fillers such as clay, kaolin, talc, and wood flour; extenders such as flour; pigments such as titanium oxide; and other plasticizers; It may contain various additives such as an antifoaming agent, a dispersant, an antifreezing agent, a preservative, and a rust inhibitor. Examples of the plasticizer include dibutyl phthalate, texanol, butyl carbitol acetate, diethylene glycol dibenzoate, propylene glycol dibenzoate, benzyl alcohol, and phenoxyethanol. The aqueous emulsion composition of the present invention is used in various applications such as woodworking adhesives, paperworking adhesives, paints, and fiber treatment agents, taking advantage of its high water resistance and high boiling water adhesion.

[0020]

Next, the present invention will be described in more detail with reference to Examples and Comparative Examples. In the following Examples and Comparative Examples, “parts” and “%” mean on a weight basis unless otherwise specified.

Production Example 1 of Aqueous Emulsion Ion-exchanged water was placed in a 1-liter glass polymerization vessel equipped with a reflux condenser, a dropping funnel, a thermometer and a nitrogen inlet.
g of PVA-1 (polymerization degree: 1000, saponification degree: 99 mol%, ethylene modification amount: 7 mol%), and the mixture was stirred at 95 ° C. for 2 hours and completely dissolved. Next, after cooling this PVA aqueous solution and replacing with nitrogen, stirring at 200 rpm,
After the temperature was raised to 60 ° C., 4.4 g of a 10% aqueous solution of tartaric acid was added.
And 3 g of a 5% aqueous hydrogen peroxide solution (0.015 in molar ratio with respect to vinyl acetate) were added by shot, and 26 g of vinyl acetate was added.
And 0.26 g of diacetone acrylamide were charged to initiate polymerization. 30 minutes after the start of the polymerization, completion of the initial polymerization was confirmed. After adding 0.9 g of a 10% aqueous solution of tartaric acid and 3 g of 5% aqueous hydrogen peroxide in a shot, 234 g of vinyl acetate and 2.34 g of diacetone acrylamide were continuously added over 2 hours to complete the polymerization, and the solid content concentration was reduced. 4
An 8.5% polyvinyl acetate emulsion (1 part by weight of diacetone acrylamide per 100 parts by weight of vinyl acetate unit) was obtained. To 100 parts by weight (solid content) of this emulsion, 5 parts of phenoxyethanol was added and mixed as a plasticizer (Em-1).

Production Example 2 of Aqueous Emulsion A 300 ml ion-exchanged water was placed in a 1-liter glass polymerization vessel equipped with a reflux condenser, a dropping funnel, a thermometer and a nitrogen inlet.
26 g of PVA-2 (polymerization degree: 1700, saponification degree: 95 mol%, ethylene modification amount: 5 mol%) was charged and stirred at 95 ° C. for 2 hours to completely dissolve. Next, the PVA aqueous solution was cooled, replaced with nitrogen, and then stirred at 200 rpm at 60 ° C.
After heating to 4.4 g, 4.4 g of a 10% aqueous solution of tartaric acid and 3 g of a 5% aqueous hydrogen peroxide solution (at a molar ratio of 0.015 with respect to vinyl acetate) were added, and then 26 g of vinyl acetate and 0.1 g of diacetone acrylamide were added. 26 g was charged and polymerization was started. 30 minutes after the start of the polymerization, completion of the initial polymerization was confirmed. After 0.9 g of a 10% aqueous solution of tartaric acid and 3 g of a 5% aqueous hydrogen peroxide solution were added in a shot, 234 g of vinyl acetate and 2.34 g of diacetone acrylamide were continuously added over 2 hours to complete the polymerization, and the solid content was increased. 4
An 8.5% polyvinyl acetate emulsion (1 part by weight of diacetone acrylamide per 100 parts by weight of vinyl acetate unit) was obtained. To 100 parts by weight (solid content) of this emulsion, 5 parts of phenoxyethanol was added and mixed as a plasticizer (Em-2).

Production Example 3 of Aqueous Emulsion In Production Example 1 of aqueous emulsion, PVA-3 (PVA-117 manufactured by Kuraray; polymerization degree 170) was used instead of PVA-1.
0, a saponification degree of 98.5 mol%), except that aqueous emulsion (E
m-3) was obtained.

Aqueous emulsion production example 4 Aqueous emulsion production example 1 except that diacetone acrylamide was not used in the aqueous emulsion production example 1.
In the same manner as in the above, an aqueous emulsion (Em-4) was obtained.

Aqueous Emulsion Production Example 5 An aqueous emulsion (Em-5) was obtained in the same manner as in the aqueous emulsion production example 1 except that allyl acetoacetate was used in place of the diacetone acrylamide used in the aqueous emulsion production example 1. .

Example 1 "Em-1" 1 obtained in Production Example 1 of an aqueous emulsion
An aqueous emulsion composition was prepared by mixing 1 part by weight of adipic dihydrazide with respect to 00 parts by weight (solid content). The film water resistance, boiling water adhesion and viscosity stability of the obtained aqueous emulsion composition were evaluated in the following manner. Table 1 shows the results.

(Evaluation of Emulsion) (1) Water Resistance of Film The obtained aqueous emulsion was cast on a polyethylene terephthalate (PET) film at 20 ° C. and 65% RH, dried for 7 days, and dried to a thickness of 500 μm. I got This film was punched out to a diameter of 2.5 cm, and the sample was immersed in boiling water for 4 hours to determine the water absorption and elution rate of the film. Dissolution rate (%): {1- (weight of dried film after immersion / weight of dried film before immersion)} × 100 Water absorption (%): 吸 (weight of absorbed water of film after immersion / weight of dried film before immersion) Weight) -1｝ × 100 * Absolute dry weight of film before immersion; Film weight (water content) before immersion-
皮膜 Coating weight before dipping (water content) x film water content (%) / 10
0｝ * Moisture content of the film: The film (sample different from the sample immersed in boiling water) is absolutely dried at 105 ° C. for 4 hours, and the moisture content of the film is determined in advance. * Weight of absolutely dried film after immersion: Weight of absolutely dried film after immersion at 105 ° C for 4 hours. * Water absorption weight of film after immersion: After the film after immersion was pulled out of water, water on the film was wiped off with gauze and weighed. (2) Adhesive strength to boiling water 150 g of the obtained aqueous emulsion was applied to Tsuga wood (straight grain).
/ M ² applied and bonded together with a load of 7 kg / m ² for 16
Time clamped. Then, after decompressing and curing for 5 days at 20 ° C. and 65% RH, it was immersed in boiling water for 4 hours, and the compressive shear strength was measured in a wet state. (3) Viscosity stability 30 minutes when the emulsion was left at 5 ° C. and 50 ° C.
The change in viscosity after a day was observed.

Example 2 A test was conducted in the same manner as in Example 1 except that 0.05 parts by weight of adipic dihydrazide was used. The results are shown in Table 1.

Example 3 A test was conducted in the same manner as in Example 1 except that 3 parts by weight of adipic dihydrazide was used. The results are shown in Table 1.

Comparative Example 1 A test was conducted in the same manner as in Example 1 except that no adipic dihydrazide was used. The results are shown in Table 1.

Example 4 The procedure of Example 1 was repeated, except that “Em-2” obtained in Aqueous Emulsion Production Example 2 was used instead of “Em-1” obtained in Aqueous Emulsion Production Example 1. The test was performed in the same manner. The results are shown in Table 1.

Comparative Example 2 The procedure of Example 1 was repeated, except that “Em-3” obtained in Aqueous Emulsion Production Example 3 was used instead of “Em-1” obtained in Aqueous Emulsion Production Example 1. The test was performed in the same manner. The results are shown in Table 1.

Comparative Example 3 The procedure of Example 1 was repeated, except that “Em-4” obtained in Aqueous Emulsion Production Example 4 was used instead of “Em-1” obtained in Aqueous Emulsion Production Example 1. The test was performed in the same manner. The results are shown in Table 1.

Comparative Example 4 A 1-liter glass polymerization vessel equipped with a reflux condenser, a dropping funnel, a thermometer and a nitrogen inlet was charged with 100 parts of ion-exchanged water.
Parts, acetoacetyl group-modified PVA (polymerization degree 1030, saponification degree 98.5 mol%, acetoacetyl group modification amount 5.0
Mol%) of vinyl alcohol-based polymer (5 parts).
Dissolved completely at ° C. Next, this PVA aqueous solution is cooled,
After replacing with nitrogen, vinyl acetate 1 was stirred at 140 rpm.
After charging 0 parts and heating to 60 ° C., polymerization was started in the presence of a hydrogen peroxide / tartaric acid redox initiator system. After 15 minutes from the start of the polymerization, 90 parts of vinyl acetate were continuously added over 3 hours to complete the polymerization. Solids concentration 55
% Polyvinyl acetate emulsion was obtained. To 100 parts by weight (solid content) of this emulsion, 5 parts of phenoxyethanol was added and mixed (Em-6). 40% based on 100 parts by weight (solid content) of the obtained “Em-6”
5 parts by weight of glyoxal aqueous solution (2 parts by weight in solid content)
An aqueous emulsion composition was prepared by blending. The film water resistance, the boiling water resistance and the viscosity stability of the obtained aqueous emulsion composition were evaluated in the same manner as in Example 1.
The results are shown in Table 1.

Example 5 A test was performed in the same manner as in Example 1 except that Em-5 obtained in Aqueous Emulsion Production Example 5 was used instead of Em-1 obtained in Aqueous Emulsion Production Example 1. Was done. The results are shown in Table 1.

Example 6 "Em-1" 1 obtained in Production Example 1 of aqueous emulsion
50 parts by weight (solid content) of 50% calcium carbonate
An aqueous emulsion composition was prepared by blending 1 part by weight of adipic dihydrazide with 1 part by weight of adipic acid. The film water resistance, the boiling water resistance, and the viscosity stability of the obtained aqueous emulsion composition were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0037]

[Table 1]

[0038]

Industrial Applicability The aqueous emulsion composition of the present invention has excellent standing viscosity stability, excellent water resistance and boiling water adhesion, and is used for woodworking adhesive, plywood adhesive, paper processing agent, and paint. Widely and suitably used for fiber processing agents and the like.

Claims (4)

[Claims] 1. A vinyl ester-based monomer unit containing 1 to 20 mol% of an α-olefin unit having 4 or less carbon atoms in a molecule thereof and a vinyl alcohol-based polymer having a saponification degree of 90 mol% or more as a dispersant. Aqueous emulsion composition comprising an aqueous emulsion (A) containing a polymer containing 0.1 to 10 parts by weight of a monomer unit having a carbonyl group in a molecule per 100 parts by weight and a hydrazine compound (B) object. 2. The aqueous emulsion composition according to claim 1, wherein the α-olefin unit having 4 or less carbon atoms is an ethylene unit. 3. The hydrazine compound (B) is added in an amount of 0.00.0 parts by weight based on 100 parts by weight (solid content) of the aqueous emulsion (A).
3. The aqueous emulsion composition according to claim 1, which is contained in a proportion of 1 to 10 parts by weight. 4. The composition according to claim 1, which contains calcium carbonate.
An aqueous emulsion composition according to any one of the above.