JP3076597B2 - Method for producing polymer latex - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a polymer latex capable of forming a film having excellent water repellency, pollution control, weather resistance, pigment dispersibility, gloss, water resistance and adhesion. And a method for producing the same. The polymer latex produced in the present invention is used for paints, adhesives, pressure-sensitive adhesives, paper processing agents, fiber processing agents, and the like, and is particularly useful for coatings.

[Problems to be solved by conventional technology and invention]

In the case of exterior paint, the paint film follows the opening and closing of the cracks in the concrete base due to temperature changes, etc. without breaking, and keeps the waterproof function to prevent concrete deterioration, or for metal In paint, flexibility of the film is required for post-bending workability. However, if importance is placed on flexibility, the film is contaminated with dust, soot, sand and the like. Conventionally, in order to compensate for the conflicting properties of film contamination control and flexibility, the
No. 9176 discloses a soft core-hard shell type layered latex, and a power feed type latex disclosed in Japanese Patent Publication No. 51-46555. However, there is a limit in compensating for the conflicting properties of suppressing the contamination of the film and flexibility, and these are required to be more advanced.

In order to solve the above problems, a polymer latex prepared by emulsion polymerization of an ethylenically unsaturated monomer, and an organopolysiloxane formed from a hydrolyzable silane compound in the copolymer contains As coexisting or chemically bonded latex or a method for producing the latex, there are methods disclosed in JP-A-60-181173, JP-A-26-267374 and JP-A-2-67324.
Since the ethylenically unsaturated monomer and the hydrolyzable silane are simultaneously introduced into the reaction system, the organopolysiloxane is relatively likely to be present on the surface of the latex particles, and the film exhibits contradictory properties of contamination control and flexibility. However, when the latex is used as a vehicle and a dispersant is added to be mixed with the inorganic pigment, the latex is agglomerated, or a film having excellent gloss cannot be obtained even if the latex can be mixed without being agglomerated. Was.

In JP-A-61-9463, JP-A-63-202630 and JP-A-63-202631, after emulsion polymerization of an ethylenically unsaturated monomer, a hydrolyzable silane is added to the reaction system. Since the polymer is introduced and polymerized, organopolysiloxane is present on the surface of the latex particles formed from the ethylenically unsaturated monomer, and the film can exhibit contradictory properties such as suppression of contamination and flexibility. However, it is difficult to stably obtain a high-concentration latex in industrial production because it also covers the dispersion-stable groups on the surface of the latex particles.Moreover, the latex is used as a vehicle and a dispersant is added. When mixed with an inorganic pigment, a latex aggregated or a film excellent in gloss could not be obtained even if the latex could be mixed without aggregation.

Further, Japanese Patent No. 905458 and JP-A-61-106614
In the gazette, the emulsion polymerization of the ethylenically unsaturated monomer after the emulsion polymerization of the silane compound first, so that the organopolysiloxane hardly exists on the surface of the latex particles,
The contradictory properties of suppressing contamination of the film and flexibility were not able to be exhibited.

[Means for solving the problem]

The present inventors have made intensive studies to solve the above problems, and have completed the present invention.

That is, the present invention provides, as a first step, (a) 0.5 to 50% by weight of an ethylenically unsaturated monomer having a carboxyl group and (b) an ethylenically unsaturated monomer having no carboxyl group in an aqueous medium. Emulsion polymerization of a monomer mixture consisting of 50 to 99.5% by weight yields a seed latex, and in the presence of the seed latex and a hydrolyzable silane, (c) 0.1 to 0.1% of an ethylenically unsaturated monomer having a carboxyl group. A second step of flowing in and polymerizing 10% by weight of a monomer mixture comprising (d) 90 to 99.9% by weight of an ethylenically unsaturated monomer having no carboxyl (d). It is a manufacturing method.

In the present invention, the seed latex obtained in the first step comprises (a) 0.5 to 50% by weight of an ethylenically unsaturated monomer having a carboxyl group, and (b) an ethylenically unsaturated monomer having no carboxyl group. It is preferable to carry out emulsion polymerization of a monomer mixture consisting of 50 to 99.5% by weight. The weight ratio of the seed latex obtained in the first step to the polymer formed from the ethylenically unsaturated monomer having a carboxyl group and other ethylenically unsaturated monomers in the second step is 5%. / 95 to 80/20 is preferred. Further, a polymer formed from an ethylenically unsaturated monomer having a carboxyl group and other ethylenically unsaturated monomers in the first and second steps, and an organopolysiloxane formed from a hydrolyzable silane Is 50
/ 50 to 99/1 is preferred.

If the requirements of the present invention are not met, the film cannot exhibit the contradictory properties of contamination suppression and flexibility as a film, or latex generates aggregates during pigment mixing, or the pigment mixed The coating has poor gloss and cannot produce a high-concentration latex stably.

In the present invention, the second step may be divided into two or more steps within the range satisfying the above requirements.

Examples of the ethylenically unsaturated monomer having a carboxyl group in the present invention include acrylic acid, methacrylic acid, itaconic acid, fumaric acid, maleic acid, and maleic anhydride.

In the present invention, the ethylenically unsaturated monomer refers to an ethylenically unsaturated monomer having no carboxyl group, and an aromatic monomer such as acrylic acid ester, methacrylic acid ester, styrene and vinyl toluene, and vinyl acetate. , Vinyl propionate, vinyl esters such as vinyl persatic acid,
There are vinyl cyanides such as (meth) acrylonitrile, vinyl halides such as vinyl chloride and vinylidene chloride, butadiene, etc., and various functional monomers such as (meth) acrylamide, diacetone acrylamide, vinylpyrrolidone, and the like. 2-hydroxyethyl (meth) acrylate, N-methylolacrylamide, N-butoxymethylacrylamide, acid phosphooxyethyl methacrylate, 3-chloro-2-acid phosphooxypropyl methacrylate, methylpropanesulfonic acid acrylamide, divinylbenzene, Methyl vinyl ketone, (poly) oxyethylene mono (meth) acrylate, (poly) propylene glycol (meth) acrylate, allyl (meth) acrylate, (poly) oxyethylene di (meth) acrylate Etc. trimethylolpropane tri (meth) acrylate.

Acrylic ester or methacrylic ester [hereinafter sometimes simply referred to as (meth) acrylic ester. ]
As, for example, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate,
There are 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, dodecyl (meth) acrylate and the like.

The hydrolyzable silane of the present invention is represented by the general formula (R ₁ ) _n -Si- (R ₂ ) _4-n (wherein R ₁ is an aliphatic hydrocarbon group having ₁ to 16 carbon atoms, an aryl group, A cycloalkyl group or a hydrogen atom, R ₂ is an organoalkoxysilane represented by an alkoxy group having 1 to 8 carbon atoms, an acetoxy group, a hydroxyl group, and n is a positive integer of 1 to 3, and R ₁ is 2 R ₁ when there are 3 or 3
May be the same or partially or entirely different. Further may be different partially or entirely be the same R ₂ are all when R ₂ is 2 or 3 are present. In the alkoxysilanes, R ₁ is particularly preferably a methyl group or a phenyl group. R ₂ is particularly preferably a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a methoxyethoxy group, or a hydroxyl group. Specific examples of alkoxysilanes include methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, isobutyltrimethoxysilane, Methylphenyldimethoxysilane and the like are particularly preferably used.

Examples of the alkoxysilanes other than the above formulas include vinyltris (β-methoxyethoxy) silane, vinyltriethoxysilane, vinylethoxysilane, γ-acryloxypropyltrimethoxysilane, and γ-copolymerizable with an ethylenically unsaturated monomer. Γ-glycidoxypropyltrimethoxysilane having other functional groups such as methacryloxypropyltrimethoxysilane, γ- (meth) acryloxypropyltriethoxysilane, γ- (meth) acryloxypropyldimethoxymethylsilane, N- β (aminoethyl) γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, tetramethoxysilane, tetraethoxysilane and the like can also be used.

Examples of chlorosilanes include methylchlorosilane,
Examples include methyldichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, phenyltrichlorosilane, diphenylchlorosilane, vinylchlorosilane, γ- (meth) acryloxypropyltrichlorosilane, and γ- (meth) acryloxypropyldichloromethylsilane.

As the cyclic silane, octamethylcyclotetrasiloxane, octaphenylcyclosiloxane, hexamethylcyclotrisiloxane, decamethylcyclopentasiloxane, tetramethyltetrabitylcyclotetrasiloxane, and the like can also be used.

One or two or more of these hydrolyzable silanes may be used in combination, and a hydrolyzable silane copolymerizable with an ethylenically unsaturated monomer having a carboxyl group and an ethylenically unsaturated monomer, Combination with other hydrolyzable silanes is particularly preferred.

In the practice of the present invention, a usual emulsion polymerization method can be adopted.
Radical polymerization catalysts are those that cause addition polymerization of ethylenically unsaturated monomers as radical decomposition by heat or a reducing substance, and include water-soluble or oil-soluble persulfates, peroxides, azobis compounds, and the like. Can be used. Examples thereof include potassium persulfate, sodium persulfate, ammonium persulfate, hydrogen peroxide, t-butyl hydroperoxide, t-butyl peroxybenzoate, 2,2
Azobisisobutyronitrile, 2,2-azobis (2-
Diaminopropa) hydrochloride, 2,2-azobis (2,4-dimethylpareronitrile) and the like, and particularly those which are water-soluble are preferably used. 0.1 to 1% by weight is blended. When it is desired to accelerate the polymerization rate and further perform polymerization at a low temperature, a reducing agent such as sodium bisulfite, ferrous chloride, ascorbate, or Rongalite is used in combination with a radical polymerization catalyst.

It is also possible to add a chain transfer agent for adjusting the molecular weight, such as dodecyl mercaptan, if desired.

In the present invention, hydrochloric acid, methanesulfonic acid, p-toluenesulfonic acid, β-naphthalenesulfonic acid, 2-mesitylenesulfonic acid, camphor-10-sulfonic acid, Boron fluoride or the like is used. Particularly, it is possible to use one having both functions of an acid catalyst such as hexylbenzenesulfonic acid, octylbenzenesulfonic acid, decylbenzenesulfonic acid, dodecylbenzenesulfonic acid, and cetylbenzenesulfonic acid, and a surfactant for emulsion polymerization. preferable.

In the present invention, conventional surfactants such as fatty acid soaps, alkyl sulfonates, alkyl sulfosuccinates, polyoxyethylene alkyl sulfates, polyoxyethylene alkyl aryl sulfates, p-styrene sulfonate and other anionic surfactants Surfactants and nonionic surfactants such as polyoxyethylene alkylaryl ether, polyoxyethylene sorbitan fatty acid ester, and oxyethylene oxypropylene block copolymer are used.

In the present invention, after the emulsion polymerization, as a curing catalyst at the time of film formation, for example, dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin diacetate, tin octylate, tin laurate, iron octylate, lead octylate,
Metal salts of organic acids such as tetrabutyl titanate and amine compounds such as n-hexylamine and 1,8-diazabicyclo [5,4,0] -7-undecene can be added to the polymer latex.

It is desirable that these curing catalysts be emulsified with a surfactant and water before use.

The pH of the polymer latex produced by the present invention is preferably adjusted to the range of 5 to 10 in order to maintain the long-term dispersion stability of the latex.

In the polymer latex produced according to the present invention, components usually added and blended in an aqueous paint or the like, for example, a thickener,
It is optional to mix an antifoaming agent, a pigment, a dispersant, a dye, a preservative, and the like.

〔Example〕

Next, the present invention will be specifically described with reference to examples and comparative examples. However, it is needless to say that the scope of the present invention is not limited only to these examples. In the examples, parts and percentages are by weight.

Example 1 In a reaction vessel equipped with a stirrer, a reflux condenser, a dropping layer and a thermometer, 8 parts of methacrylic acid, 52 parts of methyl methacrylate, 40 parts of butyl acrylate, 300 parts of water, and 40% of sodium dioctyl sulfosuccinate were used. Aqueous solution (Kao Corporation)
And 2 parts of Perex OTP-P), 1 part of a 25% aqueous solution of poeoxyethylene nonylphenyl ether (Emulgen 950, manufactured by Kao Corporation) and 1 part of dodecylbenzenesulfonic acid. After raising the temperature to 0.5 ° C., 0.5 part of ammonium persulfate is added and kept for 1 hour. This prepares the first stage seed latex.

Next, 3 parts of methacrylic acid and 207 of methyl methacrylate were used.
Parts, 190 parts of butyl acrylate, 330 parts of water, 25% aqueous solution of polyoxyethylene nonylphenyl ether (Kao Corporation)
A mixture of 5 parts of Emulgen 950) and 1.0 part of ammonium persulfate, and a mixture of 2.5 parts of γ-methacryloxypropyltrimethoxysilane, 25 parts of dimethyldimethoxysilane and 25 parts of methyltrimethoxysilane are placed in a reaction vessel. It is allowed to flow over 3 hours from separate dripping tanks. During the inflow, the temperature in the reaction vessel is maintained at 80 ° C. After the inflow is completed, the temperature in the reaction vessel is maintained at 85 ° C. for 6 hours. After cooling to room temperature
Adjust the pH to 8 by adding 25% aqueous ammonia and then
The mixture was filtered through a 100 mesh wire mesh. The dry weight of the filtered agglomerates was very low, 0.02% of the total monomer. The obtained latex has a solid content of 44.1% and a particle size of 980.
Was Å.

Next, a paint having the following composition was prepared from the obtained polymer latex.

Paint formulation Pigment dispersion Water 82.5 parts Poise 530 * 1 7.5 parts 5% aqueous solution of sodium tripolyphosphate 7.5 parts 3% aqueous solution of Daicel HEC SP-600 * 2 25.0 parts Nopco 1497VD * 3 2.5 parts TYPAKE R-930 * 4 375.0 Part Letdown polymer latex 1000.0 parts Ethylene glycol monobutyl ether 60.0 parts Ethylene glycol mono-2-ethylhexyl ether
10.0 parts Water 30.0 parts NOPCO 1497VD 1.0 part (Note) Note 1 Dispersant: manufactured by Kao Corporation Note 2 Thickener: manufactured by Daicel Chemical Industries, Ltd. Note 3 Antifoaming agent: manufactured by San Nopco, Inc. Note 4 rutile type Titanium oxide: manufactured by Ishihara Sangyo Co., Ltd. A 0.5 mm-thick coating film was obtained from this coating by drying at room temperature.
After drying at 2 ° C. for 2 days, a tensile test was performed using a dumbbell No. 2 at 20 ° C. and a humidity of 65%, and the tensile strength and the elongation between the marked lines were measured. When the tensile speed was 200 mm / min, the tensile strength was 90 kg / cm ² and the elongation was 260%. Further, this coating material was applied to a sulfated alumite plate using a wire coater No. 50, and dried at room temperature for 2 hours. The 60 ° -60 ° specular reflectance at that time was 77.5%. A further contamination test was performed. 50 specimens
After drying at 70 ° C for 2 days, kerosene is burned under the condition of 70 ° C, soot is adhered to the coating surface for 2 hours, and cooled to room temperature.
The whiteness (Y value) of the washed paint film was measured by a colorimeter (CR-230, manufactured by Minolta Camera Co., Ltd.), and the contamination recovery rate was measured by the following equation. As a result, the pollution recovery rate
87%. In addition, outdoor exposure (a direct exposure test with a 45 ° tilt angle facing south, location: night light in Kawasaki-ku, Kawasaki-city, Kanagawa Prefecture) was performed for three months (from June 11, 1990 to September 10, 1990), and the pollution recovery rate was similarly increased. It was 95% when measured.

Comparative Example 1 Polymerization was carried out in the same manner as in Example 1 except that γ-methacryloxypropyltrimethoxysilane, dimethyldimethoxysilane and methyltrimethoxysilane were excluded from the polymerization recipe of Example 1, and after cooling to room temperature, a 25% aqueous ammonia solution was used. Was added to adjust the pH to 8, followed by filtration through a 100-mesh wire mesh. The dry weight of the filtered agglomerates was very low, 0.01% of the total monomer. The obtained latex had a solid content of 43.8% and a particle size of 870 °.

Next, a coating material was prepared from the obtained polymer latex in the same manner as in Example 1, and a test similar to that in Example 1 was performed.
The tensile strength was 83 kg / cm ² and the elongation was 270%. 60 degrees -6
The specular reflectance at 0 degree was 77.0%, and the contamination recovery rate in the contamination test by burning kerosene was 76%. After three months of outdoor exposure, the pollution recovery rate was 84%.

Comparative Example 2 300 parts of water and a 40% aqueous solution of sodium dioctylsulfosuccinate (manufactured by Kao Corporation, Perex) were placed in a reaction vessel equipped with a stirrer, reflux condenser, dropping tank and thermometer.
OT-P) 2 parts, 25% aqueous solution of polyoxyethylene nonylphenyl ether (Emulgen 950, manufactured by Kao Corporation)
And 1 part of dodecylbenzene sulfonic acid, and the temperature in the reaction vessel was raised to 80 ° C.
Parts, 259 parts of methyl methacrylate, 230 parts of butyl acrylate
Parts, water 330 parts, 25% aqueous solution of polyoxyethylene nonylphenyl ether (Emulgen 950, manufactured by Kao Corporation) 5
, A mixed solution consisting of 1.0 part of ammonium persulfate and a mixed solution consisting of 2.5 parts of γ-methacryloxypropylmethoxysilane, 25 parts of dimethyldimethoxysilane, and 25 parts of methyltrimethoxysilane from a separate dropping tank into a reaction vessel for 3 hours. And let it flow in. During the inflow, keep the temperature in the reaction vessel at 80 ° C, and then set the temperature in the reaction vessel to 85 ° C after the inflow.
Keep time. After cooling to room temperature, a 25% aqueous ammonia solution was added to adjust the pH to 8, followed by filtration through a 100-mesh wire net. The dry weight of the filtered aggregate is 0.
It was slightly higher at 35%. The resulting latex solid is
44.0% and the particle size was 900 mm.

Next, a coating material was prepared from the obtained polymer latex in the same manner as in Example 1, and the same test as in Example 1 was carried out. As a result, the tensile strength was 89 kg / cm ² and the elongation was 270%. 60
The degree of specular reflectance of -60 degrees was 63.0%, and the contamination recovery rate in the pollution test by burning kerosene was 88%. After three months of outdoor exposure, the pollution recovery rate was 96%.

Comparative Example 3 300 parts of water and a 40% aqueous solution of sodium dioctylsulfosuccinate (manufactured by Kao Corporation, Perex Co., Ltd.) were placed in a reaction vessel equipped with a stirrer, reflux condenser, dropping tank and thermometer.
OT-P) 2 parts, 25% aqueous solution of polyoxyethylene nonylphenyl ether (Emulgen 950, manufactured by Kao Corporation)
Parts, dodecylbenzenesulfonic acid 1 part, γ-methacryloxypropyltrimethoxysilane 2.5 parts, dimethylmethoxysilane 25 parts, methyltrimethoxysilane 25 parts, P-
0.05 parts of tert-butyl catechol is added, and the temperature in the reaction vessel is raised to 80 ° C. and maintained for 3 hours. Next, methacrylic acid
11 parts, methyl methacrylate 259 parts, butyl acrylate 230
Parts, water 330 parts, 25% aqueous solution of polyoxyethylene nonylphenyl ether (Emulgen 950, manufactured by Kao Corporation) 5
And a mixture of 1.0 part of ammonium persulfate from the dropping tank.
Let it flow in over time. During the inflow, raise the temperature in the reaction vessel to 80.
Keep at ° C. After the inflow is complete, raise the temperature in the reaction vessel to 85 ° C
And hold for 6 hours. After cooling to room temperature, the pH was adjusted to 8 by adding a 25% aqueous ammonium solution, followed by filtration through a 100-mesh wire net. The dried amount of the filtered aggregate was very small at 0.02% based on the total monomers. The solid content of the obtained latex was 44.2%, and the particle diameter was 950 °.

Next, a coating was prepared from the obtained polymer latex in the same manner as in Example 1, and the same test as in Example 1 was carried out. As a result, the tensile strength was 87 kg / cm ² , and the elongation was 280%. 60
The degree of mirror reflection at -60 degrees was 62.0%, and the contamination recovery rate in the contamination test by burning kerosene was 77%. After three months of outdoor exposure, the pollution recovery rate was 89%.

Comparative Example 4 300 parts of water and a 40% aqueous solution of sodium dioctylsulfosuccinate (manufactured by Kao Corporation, Perex, Inc.) were placed in a reaction vessel equipped with a stirrer, reflux condenser, dropping tank and thermometer.
OT-P) 4.5 parts, 25% aqueous solution of polyoxyethylene nonylphenyl ether (Emulgen 950, manufactured by Kao Corporation)
1 part, the temperature in the reaction vessel was raised to 80 ° C., then 3 parts of methacrylic acid, 177 parts of methyl methacrylate, 213 parts of butyl acrylate, 300 parts of water, 25% aqueous solution of polyoxyethylene nonylphenyl ether ( Emulgen, manufactured by Kao Corporation
950) A mixed solution of 5 parts and 1.0 part of ammonium persulfate is allowed to flow from the dropping tank over 3 hours. During the inflow, the temperature in the reaction vessel is maintained at 80 ° C. The temperature in the reaction vessel is further raised to 80 ° C for 1 hour.
8 parts of methacrylic acid and 75 parts of methyl methacrylate
Parts, a mixture of 17 parts of butyl acrylate, and a 2% aqueous solution of ammonium persulfate in a separate dripping tank into a reaction vessel in a volume of 1%.
Let it flow in over time. During the inflow, raise the temperature in the reaction vessel to 80.
Keep at ° C. After the inflow is complete, raise the temperature in the reaction vessel to 85 ° C
And keep for 2 hours. After cooling to room temperature, a 25% aqueous ammonia solution was added to adjust the pH to 8, followed by filtration through a 100-mesh wire net. The dry weight of the filtered agglomerate was 0.20% based on the total monomer. The solid content of the obtained latex is
44.0% and the particle size was 900 mm.

Next, the obtained polymer latex was prepared into a coating material in the same manner as in Example 1, and the same test as in Example 1 was performed.
The tensile strength was 95 kg / cm ² and the elongation was 220%. 60 degrees -6
The 0 degree specular reflectance was 61.0%, and the contamination recovery rate in the pollution test by burning kerosene was 82%. After three months of outdoor exposure, the pollution recovery rate was 92%.

Comparative Example 5 300 parts of water and a 40% aqueous solution of sodium dioctylsulfosuccinate (manufactured by Kao Corporation, Perex) were placed in a reaction vessel equipped with a stirrer, a reflux condenser, a dropping tank, and a thermometer.
OT-P) 2 parts, 25% aqueous solution of polyoxyethylene nonylphenyl ether (Emulgen 950, manufactured by Kao Corporation)
And 1 part of dodecylbenzene sulfonic acid, and the temperature in the reaction vessel was raised to 80 ° C.
Parts, methyl methacrylate 252 parts, butyl acrylate 230
Parts, γ-methacryloxypropyltrimethoxysilane 2.
5 parts, water 330 parts, 25% aqueous solution of polyoxyethylene nonyl phenyl ether (Emulgen 950, manufactured by Kao Corporation)
And a mixture of 1.0 part of ammonium persulfate from the dropping tank.
Let it flow in over time. During the inflow, raise the temperature in the reaction vessel to 80.
Keep at ° C. One hour after the completion of the inflow, the temperature in the reaction vessel is set to 60 ° C., and a mixed solution composed of 25 parts of dimethyldimethoxysilane and 25 parts of methyltrimethoxysilane flows into the reaction vessel over 1 hour. Keeping the temperature at 60 ° C 6
Continue stirring for hours. The polymer aggregated as a whole, and a stable latex could not be obtained.

Example 2 15 parts of methacrylic acid, 30 parts of methyl methacrylate, 15 parts of styrene, 40 parts of 2-ethylhexyl acrylate, 40 parts of water, 300 parts of water were placed in a reaction vessel equipped with a stirrer, a reflux condenser, a dropping tank and a thermometer. 35% aqueous solution of sodium oxyethylene nonylphenyl ether sulfate (manufactured by Kao Corporation,
Emar NC) 1 part, 25% aqueous solution of polyoxythylene nonylphenyl ether (Emulgen 950, manufactured by Kao Corporation)
Charge 2 parts and 2 parts of dodecylbenzenesulfonic acid, raise the temperature in the reaction vessel to 78 ° C, and then add ammonium persulfate.
Add 0.5 part and keep for 1 hour. This prepares the first stage seed latex. Next, methacrylic acid 3
Parts, 117 parts of methyl methacrylate, 90 parts of styrene, 190 parts of 2-ethylhexyl acrylate, 330 parts of water, 5 parts of a 25% aqueous solution of polyoxyethylene nonylphenyl ether (Emulgen 950, manufactured by Kao Corporation), ammonium persulfate
1.0 part of a mixed solution, 5.0 parts of γ-methacryloxypropyltrimethoxysilane, 30 parts of dimethyldimethoxysilane,
A mixed solution comprising 10 parts of methyltrimethoxysilane is allowed to flow into the reaction vessel from separate dropping tanks over 3 hours. During the inflow, the temperature in the reaction vessel is maintained at 80 ° C. After the inflow is completed, the temperature in the reaction vessel is maintained at 85 ° C. for 6 hours. After cooling to room temperature, a 25% aqueous ammonia solution was added to adjust the pH to 8, followed by filtration through a 100 mesh wire mesh. The dry weight of the filtered agglomerates was very low, 0.02% of the total monomer. The solid content of the obtained latex was 44.0%, and the particle size was 860 °.

Next, a coating material was prepared from the obtained polymer latex in the same manner as in Example 1, and the same test as in Example 1 was carried out. As a result, the tensile strength was 92 kg / cm ² and the elongation was 230%. 60
The specular reflectance of -60 degrees was 82.0%, and the contamination recovery rate in the contamination test by burning kerosene was 87%. After three months of outdoor exposure, the pollution recovery rate was 96%.

Comparative Example 6 300 parts of water and 1 part of a 35% aqueous solution of sodium polyoxyethylene nonylphenyl ether sulfate (Ema NC, manufactured by Kao Corporation) were placed in a reaction vessel equipped with a stirrer, a reflux condenser, a dropping tank and a thermometer. , 2 parts of a 25% aqueous solution of polyoxyethylene nonylphenyl ether (Emulgen 950, manufactured by Kao Corporation) and 2 parts of dodecylbenzenesulfonic acid were added, and the temperature in the reaction vessel was raised to 80 ° C. Parts, methyl methacrylate 147 parts, styrene 105
Liquid, 230 parts of 2-ethylhexyl acrylate, 330 parts of water, 5 parts of a 25% aqueous solution of polyoxyethylene nonylphenyl ether (manufactured by Kao Corporation, Emulgen 950), 1.0 part of ammonium persulfate, and γ-methacryloxy. Propyltrimethoxysilane 5 parts, dimethyldimethoxysilane 30
And a mixed solution consisting of 10 parts of methyltrimethoxysilane are allowed to flow into the reaction vessel from separate dropping tanks over 3 hours. During the inflow, the temperature in the reaction vessel is maintained at 80 ° C. After the inflow is completed, the temperature in the reaction vessel is maintained at 85 ° C. for 6 hours.
After cooling to room temperature, 25% aqueous ammonia was added to adjust the pH to 8.
And then filtered through a 100 mesh wire mesh. The dry weight of the filtered agglomerate was as low as 0.30% based on all monomers. The solid content of the obtained latex was 44.0%, and the particle diameter was 910 °. Next, a coating material was prepared from the obtained polymer latex in the same manner as in Example 1, and the same test as in Example 1 was carried out. The tensile strength was 89 kg / cm ² , and the elongation was 290.
%Met. The 60 ° -60 ° specular reflectance was 61.0%, and the contamination recovery rate in the contamination test by burning kerosene was 86%. Also, 3
After months of outdoor exposure, the rate of contamination recovery was 95%.

Example 3 In a reaction vessel equipped with a stirrer, a reflux condenser, a dropping tank and a thermometer, 0.5 part of an aqueous solution of 26% aqueous solution of sodium polyoxyethylene nonylphenyl ether sulfate (manufactured by Kao Corporation, Levenol WZ), water Charge 150 parts, raise the temperature in the reaction vessel to 82 ° C, and then
Parts, 115 parts of methyl methacrylate, 122.5 parts of 2-ethylhexyl acrylate, 5 parts of 2-hydroxyethyl methacrylate, 150 parts of water, 25% aqueous solution of polyoxyethylene nonylphenyl ether (Emulgen 931 manufactured by Kao Corporation) 2
A mixture of 0 part and 1 part of sodium sulfate is allowed to flow into the reaction vessel over 2 hours. During inflow, the temperature in the reaction vessel is 82 ° C
To keep. After the inflow, keep it for one hour. Next, 1 part of acrylic acid, 124 parts of methyl methacrylate,
125 parts of ethylhexyl, 150 parts of water, 15 parts of a 25% aqueous solution of polyoxyethylene nonylphenyl ether (manufactured by Kao Corporation, Emulgen 931), 2 parts of dodecylbenzenesulfonic acid,
A mixture of 1 part of sodium persulfate and a mixture of 3 parts of γ-methacryloxypropyltriethoxysilane, 85 parts of dimethyldiethoxysilane and 15 parts of phenyltrimethoxysilane were introduced into a reaction vessel from separate dropping tanks. Let it flow in over time. During the inflow, the temperature in the reaction vessel is maintained at 82 ° C. After the inflow is completed, the temperature in the reaction vessel is kept at 82 ° C. for 6 hours. After cooling to room temperature, add 25% aqueous ammonia
After adjusting the pH to 8, the mixture was filtered through a 100-mesh wire mesh.
0.04% dry weight of filtered agglomerate based on total monomer
It was slight. The solid content of the obtained latex is 52.0
% And a particle diameter of 1560 °.

Next, a coating material was prepared from the obtained polymer latex in the same manner as in Example 1, and the same test as in Example 1 was performed. As a result, the tensile strength was 103 kg / cm ² and the elongation was 195%. 60
The degree of specular reflectance at -60 degrees was 79.0%, and the contamination recovery rate in the pollution test by kerosene combustion was 86%. After three months of outdoor exposure, the rate of recovery from contamination was 95%.

〔The invention's effect〕

According to the present invention, a polymer that forms a film with excellent gloss, when highly compatible with the contradictory properties of pollution control and flexibility, which could not be achieved by conventional manufacturing techniques, and when mixed with a pigment. Latex can be obtained.

Claims (1)

(57) [Claims] (1) In an aqueous medium, as a first step, (a) an ethylenically unsaturated monomer having a carboxyl group is used.
Emulsion polymerization of a monomer mixture consisting of 5 to 50% by weight and (b) 50 to 99.5% by weight of an ethylenically unsaturated monomer having no carboxyl group to obtain a seed latex, and the seed latex and a hydrolyzable silane (C) 0.1 to 10% by weight of an ethylenically unsaturated monomer having a carboxyl group,
(D) ethylenically unsaturated monomer having no carboxyl
A second step in which a monomer mixture of 90 to 99.9% by weight is introduced and polymerized.