JP3441187B2 - Aqueous emulsion - Google Patents

Description

Detailed Description of the Invention

[0001]

INDUSTRIAL APPLICABILITY In the present invention, the dispersoid is selected from (meth) acrylic acid ester type monomer units, styrene type monomer units, diene type monomer units and vinyl halide type monomer units. It also relates to an aqueous emulsion containing at least one (co) polymer as a main component. More specifically, dispersoids having excellent water resistance and adhesive properties (especially initial adhesive strength) are (meth) acrylic acid ester-based monomer units, styrene-based monomer units, diene-based monomer units and vinyl halide-based The present invention relates to an aqueous emulsion containing, as a main component, at least one (co) polymer selected from monomer units.

[0002]

2. Description of the Related Art Conventionally, an aqueous emulsion containing a polymer as a dispersoid has been emulsified by using an anionic, nonionic, cationic or amphoteric surfactant as a dispersant or a protective colloid such as polyvinyl alcohol, cellulose ether or polyvinylpyrrolidone. It is usually produced by a polymerization method or a post-emulsification method, but the conventional dispersants as described above have a drawback that it lowers the water resistance of the aqueous emulsion film. On the other hand, in the solution type in which the polymer is dissolved in an organic solvent, the water resistance of the film is good, but it has an adverse effect on the environment, an adverse effect on the human body,
In addition to the risk of fire, the solution viscosity depends on the degree of polymerization of the polymer, so that there is a problem that it is difficult to increase the concentration as compared with an aqueous emulsion, and conversion to an aqueous emulsion is gradually made. Therefore, as a method of increasing the water resistance of the film with an aqueous emulsion type, soap-free emulsion polymerization without using a dispersant, a method in which a hydrophilic group such as an ionic group or a polyethylene glycol chain is introduced into a polymer as it is, or in an organic solvent After melting,
Various methods such as a method of self-emulsifying in water (self-emulsification method), a method of using a comonomer having a hydrophilic group such as an ionic group or a polyethylene glycol chain at the time of emulsion polymerization, a method using a so-called copolymerizable emulsifier have been investigated. At present, a balanced emulsion stability, cost, and water resistance have not yet been achieved. On the other hand, an aqueous emulsion using a water-soluble polymer such as a vinyl alcohol polymer as a protective colloid is more stable in emulsion than an aqueous emulsion using only a surfactant having an emulsifying action as an emulsion polymerization dispersion stabilizer. Good and excellent in miscibility with inorganic substances, etc., and many advantages such as being able to impart flow characteristics suitable for practical use in various applications relatively easily are recognized, and it is widely used in various applications such as adhesives and paints. It is used. However, when a conventional vinyl alcohol-based polymer is used as a protective colloid, the resulting aqueous emulsion has some problems. In some cases, a performance level that is not sufficiently satisfied with an aqueous emulsion using an alcohol polymer as a protective colloid is required. It is generally said that conventional aqueous emulsions using vinyl alcohol-based polymers as protective colloids have excellent adhesiveness and workability, but have poor water resistance of the film. It is known that this is largely due to the conventional vinyl alcohol polymer which is a dispersant. In addition, when an aqueous emulsion using a conventional vinyl alcohol polymer as a protective colloid is used for adhesion, it has a much larger initial adhesive force than an aqueous emulsion using a surfactant having emulsifying power as a dispersant. In the recent trend toward high-speed adhesion, even greater initial adhesion is required.

[0003]

DISCLOSURE OF THE INVENTION An object of the present invention is to use a conventional dispersoid as a (meth) acrylic acid ester monomer unit, a styrene monomer unit, a diene monomer unit and a vinyl halide. At least 1 selected from the system monomer units
Provided an aqueous emulsion having improved initial water resistance and improved water resistance, which was a drawback of the aqueous emulsion, without impairing various characteristics of the aqueous emulsion containing at least one (co) polymer as a main component. To do.

[0004]

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventors have found that the dispersoids are (meth) acrylic acid ester-based monomer units, styrene-based monomer units, The main component is at least one (co) polymer selected from diene monomer units and vinyl halide monomer units, the dispersant has a viscosity average degree of polymerization of 200 or more, and a weight average degree of polymerization. Vinyl having a ratio Pw / Pn of (Pw) to the number average degree of polymerization (Pn) of 4 or more and a peak position of the maximum molecular weight in the molecular weight distribution measured by GPC (gel permeation chromatography) is 3500 or more. The present invention has been completed by finding an aqueous emulsion composed of an alcoholic polymer. The vinyl alcohol polymer has a viscosity average degree of polymerization of 200 or more, Pw / Pn of 4 or more, and the peak position of the maximum molecular weight in the molecular weight distribution measured by GPC is 350.
It is necessary to simultaneously satisfy the three conditions of being 0 or more, and if even one condition is lacking, the excellent characteristics of the present invention will be lost.

The present invention will be described in detail below. In the first aspect of the present invention, the dispersoid is at least selected from a (meth) acrylic acid ester-based monomer unit, a styrene-based monomer unit, a diene-based monomer unit, and a vinyl halide-based monomer unit. The dispersant contained in the aqueous emulsion containing at least one (co) polymer as a main component has a viscosity average degree of polymerization of 2
00 or more, Pw / Pn is 4 or more, and the maximum molecular weight peak position of the molecular weight distribution measured by GPC is the degree of polymerization of 3
It is a vinyl alcohol polymer having a content of 500 or more. The vinyl alcohol polymer must contain the vinyl alcohol polymer in an amount of 0.1 to 50% with respect to the dispersoid. Here, the viscosity average degree of polymerization of the vinyl alcohol-based polymer is the viscosity average degree of polymerization obtained by the following formula from the intrinsic viscosity measured at 30 ° C. in acetone for polyvinyl acetate obtained by reacetylating the vinyl alcohol polymer. It is represented by. P = ([η] × 10 ³ /7.94) ^{(1 / 0.62)} The saponification degree of the vinyl alcohol polymer is preferably 50 to 100 mol%, more preferably 60 to 99 mol%.
The 1,2-glycol bond amount of the vinyl alcohol polymer is preferably 1.4 mol% or less, more preferably 1.2 mol% or less. The vinyl alcohol-based polymer can be contained in the aqueous emulsion by various methods, and the method is not particularly limited, but it is usually at least one selected from the above monomer group. Method of using as a dispersion stabilizer (protective colloid) at the time of emulsion (co) polymerization of the monomer of (1), (co) polymer obtained by a method other than emulsion (co) polymerization or (co) polymer aqueous solution It is also possible to post-add the vinyl alcohol polymer to an aqueous emulsion obtained by a method of using as a dispersant when emulsifying (forced emulsification or self-emulsification), or in some cases by emulsion (co) polymerization or post-emulsion method. is there.
However, the temperature during the post-addition is not particularly limited as long as it does not impair the stability of the emulsion.

In the second aspect of the present invention, the dispersoid is (meth)
As a main component, at least one or more (co) polymers selected from acrylate monomer units, styrene monomer units, diene monomer units and vinyl halide monomer units, The dispersant has a viscosity average degree of polymerization of 200 or more,
Ratio P of weight average degree of polymerization (Pw) and number average degree of polymerization (Pn)
An aqueous emulsion composed of a vinyl alcohol polymer having a w / Pn of 4 or more and having a maximum molecular weight peak position in the molecular weight distribution measured by GPC of 3500 or more and a mercapto group-containing vinyl alcohol polymer. . The vinyl alcohol-based polymer is the same as that used in the first invention, and the vinyl alcohol-based polymer needs to contain 0.1 to 50% of the vinyl alcohol-based polymer with respect to the dispersoid. Is. As the vinyl alcohol-based polymer having a mercapto group in the present invention, in addition to the terminal mercapto group, a functional group may be introduced into the main chain and side chain of the molecule, but a heavy chain having a mercapto group in the main chain of the molecule may be used. In the case of coalescence, the vinyl alcohol-based polymer itself may be insolubilized by forming a disulfide bond due to oxidation, so the vinyl alcohol-based polymer having a mercapto group only at one end of the molecule is insoluble. It is particularly preferable because there is no worry and it is easy to handle. The viscosity average polymerization degree of the vinyl alcohol-based polymer containing a mercapto group used in the present invention is 1
It is 10,000 or less, preferably less than 4000, particularly preferably 2000 or less. The saponification degree of the vinyl alcohol polymer varies depending on the type of other modifying groups, but is preferably 70 mol% or more from the viewpoint of water solubility. The vinyl alcohol-based polymer having a mercapto group used in the present invention,
Since it has an extremely active mercapto group in the radical reaction, it is more likely to be chemically bound to the dispersoid particles as compared with the conventional vinyl alcohol-based polymer having no mercapto group at the terminal, and therefore the effect of stabilizing the dispersoid is remarkable. improves.

In the present invention, the viscosity average degree of polymerization is 200.
Above, the weight average degree of polymerization (Pw) and the number average degree of polymerization (Pn)
Of the ratio (Pw / Pn) of 4 or more and the peak of the maximum molecular weight in the molecular weight distribution measured by GPC is 3500 or more and the vinyl alcohol polymer (A) and the vinyl alcohol polymer having a mercapto group at the end The blending ratio of (B) is not particularly limited, but usually 99/1 to 1/99
(Weight ratio), preferably 95/5 to 5/95. Further, the viscosity average degree of polymerization is 200 or more, and the ratio Pw / Pn of the weight average degree of polymerization (Pw) to the number average degree of polymerization (Pn) is 4
The amount of the vinyl alcohol polymer (A) having the maximum molecular weight peak in the molecular weight distribution measured by GPC measurement of 3500 or more is 0.2 to 100 parts by weight of the monomer. 40 parts by weight. The viscosity average degree of polymerization is 200 or more, the ratio Pw / Pn of the weight average degree of polymerization (Pw) to the number average degree of polymerization (Pn) is 4 or more, and GPC
When the vinyl alcohol polymer (A) having a maximum molecular weight peak in the molecular weight distribution measured by measurement of 3500 or more is less than 0.2 parts by weight, the stability of the dispersoid particles and the conventional vinyl alcohol polymer are The characteristics of the aqueous emulsion made into a protective colloid (characteristics such as mechanical stability, chemical stability, freeze-thaw stability, miscibility with inorganic substances) are
Although it can be secured by the vinyl alcohol-based polymer (B) having a mercapto group at the terminal used in combination, the effect of improving the adhesive property and coating property of the aqueous emulsion, which is the main object of the present invention, becomes small. The viscosity average degree of polymerization is 20
A weight average degree of polymerization (Pw) and a number average degree of polymerization (Pw) of 0 or more
The ratio Pw / Pn of n) is 4 or more, and the peak of the maximum molecular weight in the molecular weight distribution measured by GPC is the degree of polymerization of 350.
When the amount of the vinyl alcohol polymer (A) used, which is 0 or more, increases, the viscosity of the polymerization system may become too high, and the polymerization cannot proceed uniformly or the heat of polymerization is not sufficiently removed. It may be.

The vinyl alcohol polymer contained as a dispersion stabilizer in the aqueous emulsions of the first and second inventions is produced by hydrolysis or alcoholysis of polyvinyl ester. The vinyl ester-based polymer is a homopolymer of a vinyl ester-based monomer, a copolymer of two or more vinyl ester-based monomers, and a vinyl ester-based monomer and another ethylenically unsaturated monomer. Copolymers with the body are included.
Here, vinyl formate, vinyl acetate, vinyl propionate, vinyl versatate, vinyl pivalate and the like can be used as the vinyl ester, but among them, vinyl acetate which is industrially produced and inexpensive is generally used. The vinyl alcohol-based polymer used as a dispersion stabilizer in the aqueous emulsion of the present invention is substantially water-soluble, and other conditions are not limited as long as a stable emulsion can be obtained. It may be a copolymer having a main constituent unit or a block copolymer having polyvinyl alcohol as one component, and a polymer having a polymer terminal modified with a chain transfer agent may also be used. The dispersoid of the present invention is at least one kind selected from a (meth) acrylic acid ester-based monomer unit, a styrene-based monomer unit, a diene-based monomer unit and a vinyl halide-based monomer unit ( The vinyl alcohol polymer used as a dispersant for an aqueous emulsion containing a copolymer as a main component preferably has a viscosity average degree of polymerization of 200 to 30,000, more preferably 500.
˜20,000, particularly preferably 1,000 to 10,000, and less than 200 is not preferable from the viewpoint of initial adhesive strength and water resistance. When it is more than 30,000, it is not preferable from the viewpoint of obtaining the polymer.

Regarding the molecular weight distribution, Pw / Pn must be 4 or more, preferably 5 or more, more preferably 7 or more, and particularly preferably 10 or more. Until now, there has not been a vinyl alcohol polymer having a degree of polymerization of 3500 or more and a molecular weight distribution of 4 or more. When Pw / Pn is less than 4, the contribution on the polymer side becomes small and the initial adhesive strength and water resistance are not improved, which is not preferable. The larger the molecular weight distribution is, the more the effect of the present invention can be exhibited, but Pw / Pn is preferably 30 or less from the viewpoint of availability of a highly polymerized polyvinyl alcohol. Further, it is necessary to satisfy that the peak position of the maximum molecular weight in the molecular weight distribution measured by GPC, which is a major condition of the present invention, is a polymerization degree of 3500 or more. When measuring the degree of polymerization distribution of the vinyl alcohol-based polymer of the present invention by GPC, the vinyl alcohol-based polymer of the present invention can be measured by using an aqueous column from an aqueous solution of the vinyl alcohol-based polymer. Alternatively, it may be subjected to re-acetylation in pyridine to obtain polyvinyl acetate, and the measurement may be performed using an organic solvent-based GPC using an organic solvent, for example, tetrahydrofuran as a solvent. The peak position of the maximum molecular weight in the molecular weight distribution obtained by this measurement has a degree of polymerization of 3500 or more, preferably 5
000-30000, more preferably 6000-200
It must be 00. The peak position of the maximum molecular weight in the molecular weight distribution simply means the peak position of the maximum molecular weight when independent peaks of several peaks are obtained. It is often obtained in a form in which several single peak waveforms are superposed due to the spread of the waveform. In such a case, it is necessary to separate each peak and extract accurate values such as the peak position, height, and area. However, many methods that currently use a computer are used to separate this peak. , For example, Gauss-Newton method (GN method), Davi
don-Flecher-Powell (DFP method),
Simplex method, Damped-Least-Squ
ares (DLS method) and many improved methods thereof have been proposed, and any method can be used. It is necessary that the peak position of the maximum molecular weight among the peaks divided by these treatments has a degree of polymerization of 3500 or more. Further, the content of the vinyl alcohol-based polymer calculated from the area of the peak of the maximum molecular weight obtained by the division is not particularly limited, but preferably 5 weight% based on the total vinyl alcohol-based polymer. % Or more is preferable. That is, in the aqueous emulsion of the present invention, the vinyl alcohol-based polymer used as the dispersion stabilizer has a polymerization degree of 350.
It is necessary to contain 0 or more, and it is considered that this high molecular weight portion contributes to the improvement of initial adhesive strength and water resistance.

The method for producing the vinyl alcohol polymer to be contained as a dispersant for the aqueous emulsion of the present invention is not particularly limited, and any method may be used. For example, a method of preparing vinyl alcohol-based polymers having different degrees of polymerization in advance and blending them, a method of blending pastes of vinyl ester polymers separately polymerized to have different degrees of polymerization and then saponifying, vinyl ester A method of feeding back the polyvinyl ester solution, which has undergone polymerization during continuous polymerization using multiple polymerization tanks, to the previous polymerization layer once, and saponifying the resulting vinyl ester polymer, vinyl in the low molecular part. Examples include a method of using an alcohol-based polymer as an emulsion stabilizer, performing low-temperature emulsion polymerization of vinyl acetate, and then saponifying. A vinyl alcohol polymer having a high degree of polymerization of 3500 or more is difficult to produce by vinyl acetate polymerization at about 60 ° C. from a conventionally known methanol solution, and therefore it is difficult to produce it at a high concentration and at a low polymerization rate. It is produced by a method of polymerizing and stopping at a low polymerization rate, or in the production of PVA having a degree of polymerization of 8,000 or more, a method of performing bulk or emulsion polymerization at a room temperature region at several tens of degrees below freezing. As the aqueous emulsion in the present invention, a (meth) acrylic acid ester-based monomer unit, a styrene-based monomer unit, a diene-based monomer unit, and a vinyl halide-based monomer are used in a dispersion medium containing water as a main component. There is no particular limitation as long as it is a polymer dispersoid containing at least one (co) polymer as a main component selected from the units, and the average particle diameter of the dispersoid is usually in the range of 0.05 to 5 μm.

Examples of the (meth) acrylic acid ester-based monomer used in the present invention include acrylic acid ester or methacrylic acid ester, and specific examples thereof include methyl acrylate, ethyl acrylate, butyl acrylate, acrylic acid. 2-ethylhexyl, dodecyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, dodecyl methacrylate, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate and their quaternized products, ethylene glycol Dimethacrylate etc. are mentioned. Examples of the styrene-based monomer include styrene, α-methylstyrene, P-styrenesulfonic acid and its sodium and potassium salts. Examples of the diene-based monomer include butadiene, isoprene and chloroprene. Examples of the vinyl halide monomer include vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride and the like. Further, it is also possible to copolymerize a monomer copolymerizable with the above-mentioned monomer within a range that does not impair the effects of the present invention, and as these copolymerizable monomers, ethylene, propylene, 1-butene,
Olefinic monomers such as isobutene; vinyl ether monomers such as 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; acrylamide, N-methyl acrylamide, Acrylamide derivatives such as N-ethylacrylamide, N, N-dimethylacrylamide, diacetoneacrylamide, acrylamidopropanesulfonic acid and its salts, acrylamidopropyldimethylamine and its salts or quaternary salts thereof, N-methylolacrylamide and its derivatives; methacryl Amide, N-methyl methacrylamide, N-ethyl methacrylamide, methacrylamide propane sulfonic acid and its Methacrylamide derivatives such as methacrylamidopropyldimethylamine and its salts or quaternary salts thereof, N-methylolmethacrylamide and its derivatives; nitriles such as acrylonitrile and methacrylonitrile; allyl compounds such as allyl acetate and allyl chloride; Acid and its salt or its ester; itaconic acid and its salt or its ester; vinylsilyl compounds such as vinyltrimethoxysilane; isopropenyl acetate and the like.

In the present invention, it is necessary that the vinyl alcohol polymer is in the range of 0.1 to 50% with respect to the polymer dispersoid containing the monomer unit as a main component.
The range is preferably 0.2 to 30%, more preferably 0.5 to 10%. When the content of the vinyl alcohol polymer is less than 0.1%, the contribution of the vinyl alcohol polymer to the dispersion stabilizer of the aqueous emulsion becomes small, and in some cases, the dispersoid particles are bridged. As described above, it may be adsorbed to form a block and the dispersion stability of the aqueous emulsion cannot be sufficiently maintained. On the other hand, when the content of the vinyl alcohol-based polymer is more than 50% with respect to the polymer dispersoid, the viscosity of the aqueous emulsion becomes extremely high, which causes a problem in workability and the initial adhesive strength which is the object of the present invention. Also, water resistance is not sufficiently expressed. The saponification degree of the vinyl alcohol polymer used in the present invention varies depending on the type of other modifying groups, but is preferably 50 mol% or more, and 70 mol% from the viewpoint of water solubility.
The above is more preferable. If the degree of saponification is less than 50 mol%, the dispersion stability of the particles will be reduced, which is not suitable for the purpose of the present invention.

The dispersion stabilizer of the aqueous emulsion of the present invention may be, in some cases, other protective colloids within a range that does not impair the performance, for example, conventional polyvinyl alcohol; polyacrylic acid or polymethacrylic acid and salts thereof; polyvinyl alkyl ether; acetic acid. Vinyl and acrylic acid, methacrylic acid or maleic anhydride copolymers and saponified products thereof; lower alkyl vinyl ether-maleic anhydride copolymers; cellulose derivatives such as alkyl cellulose, hydroxyalkyl cellulose, alkyl hydroxyalkyl cellulose and carboxymethyl cellulose; alkyl Starch derivatives such as starch, carboxymethyl starch, and oxidized starch; gum arabic, tragacanth gum, and polyalkylene glycol may be contained. In addition, auxiliary agents such as liquidity modifiers, monohydric or polyhydric alcohols, plasticizers, defoaming agents and the like which have been conventionally used in emulsion polymerization may be used together during or after the polymerization. . As described above, in the aqueous emulsion of the present invention, the dispersoid is selected from (meth) acrylic acid ester-based monomer units, styrene-based monomer units, diene-based monomer units and vinyl halide-based monomer units. At least one (co) polymer as a main component, the dispersant has a viscosity average degree of polymerization of 200 or more, and the ratio Pw / Pn of the weight average degree of polymerization (Pw) to the number average degree of polymerization (Pn) is 4 Above, and the peak position of the maximum molecular weight of the molecular weight distribution measured by GPC is 3500 degree of polymerization.
It is an aqueous emulsion comprising the above vinyl alcohol polymer. The aqueous emulsion can further improve the initial adhesive strength of the conventional aqueous emulsion, and can dramatically improve the level of water resistance, which is a drawback.

[0014]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto. In addition, "%" and "part" in the examples represent "wt%" and "part by weight", respectively, unless otherwise specified. In addition, the initial adhesive strength is the adhesive strength tester ASM.
-01 (manufactured by Japan Tobacco Inc.) was used to measure the adhesive strength under the following measurement conditions. Base paper: Liner paper (Kopusaizu of 19g / m ^2/2 min) Measurement environment: 20 ℃, 65% RH adhesive coating weight: 60 g / m ² (wet coating amount) bonding temperature: 40 ° C. coating speed: 0 0.5 m / sec Leaving time after coating: 1 sec Pressing pressure: 3 kg Crimping time: 1 sec, 3 sec, 5 sec, 10 sec Leaving time after crimping: 1 sec Peeling speed: 200 mm / sec The evaluation was carried out by casting the aqueous emulsion on a Teflon sheet at 50 ° C., and drying the film for 2 weeks by immersing the film in water at 20 ° C. for 1 week to evaluate the dissolution rate (formula 1). Dissolution rate (%) = (1-weight of coating after immersion / weight of coating before immersion) x 100 (Equation 1)

Example 1 Ion-exchanged water 280 was placed in a 1 liter glass container equipped with a reflux condenser, a dropping funnel, a thermometer, and a nitrogen blowing port.
Part, polyvinyl alcohol (PVA-1: viscosity average degree of polymerization 2450, degree of saponification 88 mol%, molecular weight distribution measured by GPC gives Pw / Pn = 14.9, and this chart gives two independent peaks. The degree of polymerization at the peak position with a large molecular weight was 8100.) 15 parts were weighed and completely dissolved at 95 ° C. Then pH =
It was adjusted to 3.5. 250 parts of styrene was added with stirring at 140 rpm, the temperature was raised to 60 ° C., 10 parts of 5% ammonium persulfate was added, and after 5 hours the polymerization rate was 99.
It became 9% and cooled. After adjusting the pH of the generated emulsion to 6.8 with aqueous ammonia, the physical properties, water resistance and adhesive performance of the emulsion were measured. The results are shown in Table 1.

Example 2 To 290 parts of ion-exchanged water was added polyvinyl alcohol (PVA-
2: viscosity average degree of polymerization 1760, degree of saponification 90 mol%, G
When the molecular weight distribution was measured by PC, Pw / Pn = 19.
0, this chart gives two independent peaks, the degree of polymerization of the peak position of the high molecular weight is 17800, the polymer of the peak of the low molecular weight is polyvinyl alcohol having a mercapto group at the end) 12 parts 9
It was completely dissolved at 5 ° C., and it was placed in a pressure resistant autoclave equipped with a nitrogen blowing port and a thermometer. P with diluted sulfuric acid
After adjusting to H = 3.9, 165 parts of styrene and then 135 parts of butadiene were charged from a pressure resistance meter, and the temperature was adjusted to 70 ° C.
After the temperature was raised to 10 ° C., 10 parts of a 2% potassium persulfate aqueous solution was pressure-fitted to initiate polymerization. The internal pressure decreased from 4.8 kg / cm ² G as the polymerization progressed, and after 14 hours, 0.4 kg / c.
It was m ² G and the polymerization rate was calculated to be 99.2%. The obtained emulsion was pH = 6. With ammonia water.
It was set to 0 and the physical properties, water resistance and adhesive performance of the emulsion were measured. The results are shown in Table 1.

Example 3 A 1-liter glass container equipped with a reflux condenser, a dropping funnel, a thermometer and a nitrogen blowing port was charged with 280 deionized water.
Part, polyvinyl alcohol (PVA-1: viscosity average degree of polymerization 2450, degree of saponification 88 mol%, molecular weight distribution measured by GPC gives Pw / Pn = 14.9, and this chart gives two independent peaks. , The polymerization degree at the peak position having a large molecular weight was 8100) and polyvinyl alcohol having a mercapto group at the end (PVA-).
3: Viscosity average degree of polymerization 1000, degree of saponification 92 mol%, G
When the molecular weight distribution was measured by PC, Pw / Pn = 2.5
(The chart was a single peak) 17 parts were weighed out and completely dissolved at 95 ° C. Then, the pH was adjusted to 3.5 with dilute sulfuric acid. Then 180 parts of styrene and 120 parts of butyl acrylate with stirring at 140 rpm.
Then, 10 parts of 2% potassium persulfate was added to initiate polymerization. After 2 hours, 10 parts of a 2% aqueous solution of potassium persulfate was added, and the temperature was raised to 70 ° C.
After 5 hours, the polymerization rate became 99.9% and the mixture was cooled. The resulting emulsion was adjusted to pH = 6.5 with aqueous ammonia,
The physical properties, water resistance and adhesive performance of the emulsion were measured. The results are shown in Table 1.

Comparative Example 1 PVA-205 (viscosity average degree of polymerization: 175) was used as a dispersant.
0, saponification degree 88 mol%, manufactured by Kuraray Co., Ltd .; molecular weight distribution measured by GPC gives Pw / Pn = 2.5,
This chart had a single peak) (degree of polymerization 50
0, saponification degree 88.0 mol%, manufactured by Kuraray Co., Ltd. 15
The same procedure as in Example 1 was carried out except that some parts were used. The physical properties, water resistance and adhesive performance of the obtained emulsion were measured. The results are shown in Table 1.

Comparative Example 2 Sandet BL (anionic surfactant;
An emulsion was obtained in the same manner as in Example 1 except that 15 parts of Sanyo Kasei Co., Ltd. was used. The physical properties, water resistance and adhesive performance of the obtained emulsion were measured. The results are shown in Table 1.

Comparative Example 3 Example 1 except that 15 parts of nonipol 200 (nonionic surfactant; Sanyo Kasei Co., Ltd.) was used as a dispersant.
An emulsion was obtained in the same manner as in. The physical properties, water resistance and adhesive performance of the obtained emulsion were measured. The results are shown in Table 1.

Comparative Example 4 Ion-exchanged water 280 was placed in a 1 liter glass container equipped with a reflux condenser, a dropping funnel, a thermometer and a nitrogen blowing port.
Part, PVA-217 (viscosity average degree of polymerization 1700, degree of saponification 88 mol%, molecular weight distribution measured by GPC, P
w / Pn = 2.5, this chart was a single peak) 15 parts were weighed out and completely dissolved at 95 ° C. 300 parts of vinyl acetate was charged while stirring at 140 rpm, the temperature was raised to 60 ° C., and then polymerization was initiated using a hydrogen peroxide-Rongalit redox initiator. After 2 hours and 30 minutes, the polymerization rate became 99.6% and the system was cooled. The produced emulsion was adjusted to pH = 6.5 with aqueous ammonia, and the physical properties, water resistance and adhesive performance of the emulsion were measured. The results are shown in Table 1.

[0022]

[Table 1]

[0023]

[Table 2]

[0024]

[Table 3]

PVA-1: Viscosity average degree of polymerization 2450, saponification degree 88 mol%, molecular weight distribution measured by GPC gave Pw / Pn = 14.9, and this chart gave two independent peaks. The polymerization degree at the large peak position was 8100. PVA-2: viscosity-average degree of polymerization 1760, degree of saponification 90 mol%, molecular weight distribution measured by GPC Pw / Pn
= 19.0, the chart gives two independent peaks, and the degree of polymerization at the peak position of the higher molecular weight is 178.
The polymer having a low molecular weight peak was polyvinyl alcohol having a mercapto group at the terminal. PVA-3: viscosity average polymerization degree 1000, saponification degree 92 mol%, molecular weight distribution measured by GPC Pw / Pn
= 2.5, the chart was a single peak.

[0026]

As is apparent from the above examples, the present invention provides an aqueous emulsion having improved adhesive properties and water resistance as compared with conventional aqueous emulsions. The water-based emulsion of the present invention is effective as an adhesive, a paint as well as a paper and a Seny processing material which have not been heretofore,
The industrial utility value is extremely high.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-7-247400 (JP, A) JP-A-5-255410 (JP, A) JP-A-5-295010 (JP, A) JP-A-5- 295276 (JP, A) JP-A-5-345805 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08F 2/00-2/60 C08L 1/00-101/16

Claims (2)

(57) [Claims] 1. The dispersoid is at least one selected from (meth) acrylic acid ester-based monomer units, styrene-based monomer units, diene-based monomer units, and vinyl halide-based monomer units. The above-mentioned (co) polymer as a main component, the dispersant has a viscosity average degree of polymerization of 200 or more, and a weight average degree of polymerization (P
w) and the number average degree of polymerization (Pn) ratio Pw / Pn is 4 or more, and the peak position of the maximum molecular weight in the molecular weight distribution measured by GPC is a vinyl alcohol-based polymer having a degree of polymerization of 3500 or more. . 2. The dispersoid is at least one selected from (meth) acrylic acid ester-based monomer units, styrene-based monomer units, diene-based monomer units and vinyl halide-based monomer units. The above-mentioned (co) polymer as a main component, the dispersant has a viscosity average degree of polymerization of 200 or more, and a weight average degree of polymerization (P
w) and the number average degree of polymerization (Pn) ratio Pw / Pn is 4 or more, and the peak position of the maximum molecular weight of the molecular weight distribution measured by GPC is a vinyl alcohol polymer and a mercapto group having a degree of polymerization of 3500 or more. An aqueous emulsion comprising the vinyl alcohol polymer.