JP2002155209A - Aqueous resin emulsion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an aqueous resin emulsion capable of forming a coating film having excellent durability of water resistance, weather resistance, etc., when used as a raw material for an aqueous coating, etc. SOLUTION: This aqueous resin emulsion is obtained by subjected a radically polymerizable unsaturated monomer to emulsion polymerization in an aqueous medium, hydrolyzing and condensing a non-radically polymerizable organosilicon compound represented by the formula (R1)n-Si-(R2)4-n [n is an integer of 1-3; R1 is a 1-16C alkyl group, cycloalkyl group or aryl group; R2 is a 1-8C alkoxy group or hydroxy group] and simultaneously adding a photostabilizer to the polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a radically polymerizable unsaturated monomer by emulsion polymerization in an aqueous medium, followed by hydrolytic condensation of a non-radical polymerizable organosilicon compound and addition of a light stabilizer. The present invention relates to an aqueous resin emulsion obtained by the above method, and more particularly to an aqueous resin emulsion useful as a resin for paints, especially as a resin for architectural exterior paints and coating materials for various building materials that require particularly high water resistance and weather resistance.

[0002]

2. Description of the Related Art In recent years, from the viewpoints of reducing environmental impact and improving safety and health, water-based paints for building exterior paints and exterior building materials have been accelerated at an accelerating pace. There has been a shift from conventional organic solvent-based resins to aqueous resin emulsions. Inevitably, a coating film exposed to the outdoors is required to have resistance to various external stimuli such as sunlight and rainwater, and the required performance of a water-based coating material has been considerably increased. One of the most important coating materials that influences this performance is an aqueous resin emulsion.

However, a coating film obtained from an aqueous resin emulsion or a coating material in which a pigment is blended with an aqueous resin emulsion, mainly a conventional acrylic emulsion, has low durability against various stimuli. In order to solve this problem, various techniques have been proposed to increase the durability of the aqueous resin emulsion by introducing silicone and a light stabilizer and / or an ultraviolet absorber, but they are not always satisfactory. Was.

For example, Japanese Patent Application Laid-Open No. 7-173404 proposes a method in which an ultraviolet absorber and / or a light stabilizer is dissolved or suspended in a film-forming aid component and then added to a silicone-modified acrylic emulsion. But
Because the aqueous resin emulsion contains a predetermined film-forming aid in advance, which limits the formulation of the coating composition, and because of rainwater during long-term outdoor exposure, ultraviolet absorbers and light stabilizers may flow out, The durability was insufficient.

In Japanese Patent Application Laid-Open No. Hei 10-120724, an ultraviolet absorber and / or a light stabilizer is dissolved in a radical polymerizable monomer to carry out a usual emulsion polymerization of an acrylic emulsion, followed by silicone modification. A method has been proposed. However, in normal emulsion polymerization, in which the polymerization proceeds as the monomer moves from the monomer droplets to emulsifier micelles or emulsion polymer particles via water, a substance having a high oil solubility and a relatively large molecular weight is used. Cannot perform such migration, and are not easily taken into the polymer particles.

Therefore, it is difficult to introduce a certain amount of an oil-soluble ultraviolet absorber or a light stabilizer as described in the above-mentioned publication, and as described in Examples, the total amount thereof is The limit is about 1% by weight in the solid content. For this reason, the weather resistance cannot be sufficiently improved.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide an aqueous resin emulsion capable of forming a coating film having excellent durability such as water resistance and weather resistance when used as a raw material of an aqueous paint or the like. To provide.

[0008]

As a result of intensive studies to obtain a highly durable aqueous resin emulsion, a radical polymerizable unsaturated monomer was emulsion-polymerized in an aqueous medium and then non-radical polymerizable. By adding a light stabilizer simultaneously with hydrolytic condensation of the organosilicon compound, it becomes possible to obtain an aqueous resin emulsion having excellent durability,
The present invention has been completed.

That is, the present invention provides: Emulsion weight of radical polymerizable unsaturated monomer in aqueous medium
After combining, the formula (R¹) _n-Si- (R^Two)_4-n[Where n is 1-3
Integer. R¹Is an alkyl group having 1 to 16 carbon atoms,
Kill group, aryl group,: R^TwoHas 1 to 8 carbon atoms
Non-radical polymerizable compound represented by
Light stabilizer at the same time as hydrolytic condensation of organosilicon compounds
Aqueous resin emulsion obtained by adding

[0010] 2. Formulation (R ¹ ) _n -Si- (R ² ) _{4-n in which a} radical stabilizer polymerizable unsaturated monomer was emulsion-polymerized in an aqueous medium and then a light stabilizer was dissolved, wherein n is 1 to An integer of 3. R ¹ is an alkyl group having ¹ to 16 carbon atoms, a cycloalkyl group, an aryl group, R ² is an alkoxy group having 1 to 8 carbon atoms,
An aqueous resin emulsion obtained by hydrolyzing and condensing a non-radical polymerizable organic silicon compound represented by the formula:

3. The aqueous resin emulsion according to the above 1 or 2, wherein the solid content of the non-radical polymerizable organic silicon compound is 1 to 50% by weight of the solid content in the aqueous resin emulsion,

4. The aqueous resin emulsion according to any one of the above 1 to 3, wherein the light stabilizer is 0.1 to 5% by weight of a solid content in the aqueous resin emulsion.

5. 30 to 30 radically polymerizable unsaturated monomers
It is an object of the present invention to provide the aqueous resin emulsion according to any one of the above items 1 to 4, wherein 70% by weight is an alkyl methacrylate having an alkyl group having 4 or more carbon atoms.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The non-radical polymerizable organosilicon compound used in the present invention includes (R ¹ ) _n -Si- (R ² ) _4-n (n is an integer of ^{1 to} 3; R ¹ is an alkyl group having ¹ to 16 carbon atoms; cycloalkyl group, an aryl group: R ² is not particularly limited as long as it is represented by an alkoxy group, a hydroxyl group) having from 1 to 8 carbon atoms, especially typical among them To illustrate only

Methyltrimethoxysilane, ethyltrimethoxysilane, isobutyltrimethoxysilane, n-hexyltrimethoxysilane, n-decyltrimethoxysilane, n-hexadecyltrimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, Ethyltriethoxysilane, n-hexyltriethoxysilane, n-octyltriethoxysilane, phenyltriethoxysilane, dimethyldimethoxysilane, diphenyldimethoxysilane, cyclohexylmethyldimethoxysilane, dimethyldiethoxysilane, diphenyldiethoxysilane, trimethylmethoxysilane , Trimethylethoxysilane and the like, and these can be used alone or in combination of two or more.

As the hindered amine light stabilizer used in the present invention, specifically, bis (1,
2,2,6,6-pentamethyl-4-piperidinyl) sebacate (manufactured by Sankyo Co., Ltd., product name: SANOL LS-76)
5), bis (1-octoxy-2,2,6,6-tetramethyl-4-piperidinyl) sebacate (manufactured by Ciba Specialty Chemicals Co., Ltd., product name: TINUVI)
N123), N-acetyl-3-dodecyl-1- (2,
2,6,6-tetramethyl-4-piperidinyl) pyrrolidine-2,5-dione (Clariant Japan K.K.)
Manufactured, product name: Sanduvor 3058)
These can be used alone or in combination of two or more.

The radical polymerizable unsaturated monomer used in the present invention can be used without particular limitation as long as it is generally used for emulsion polymerization. For example, acrylates such as methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate; methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate; Methacrylates such as isobutyl methacrylate, t-butyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate; crotonic esters such as methyl crotonate and ethyl crotonate;

Acrylic acid, methacrylic acid, maleic acid,
Carboxyl group-containing monomers such as fumaric acid, itaconic acid, mono-n-butyl maleate, mono-n-butyl fumarate, mono-n-butyl itaconate, crotonic acid; tertiary such as vinyl acetate and vinyl propionate Vinyl esters such as vinyl carboxylate; styrene, vinyl toluene, α-
Aromatic vinyl compounds such as methylstyrene; heterocyclic vinyl compounds such as vinylpyrrolidone; halogenated olefins such as vinyl chloride, vinylidene chloride, and vinylidene fluoride;

Monomers containing cyano group such as acrylonitrile and methacrylonitrile; vinyl ethers such as ethyl vinyl ether and isobutyl vinyl ether; vinyl ketones such as methyl vinyl ketone; α-olefins such as ethylene and propylene; butadiene and isoprene Dienes; Amide group-containing monomers such as acrylamide, methacrylamide, maleic amide, N-methylolacrylamide, N-methylolmethacrylamide, diacetoneacrylamide; glycidyl group-containing monomers such as glycidyl methacrylate and allyl glycidyl ether body;

Hydroxyl-containing monomers such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate and 2-hydroxypropyl methacrylate; monomers containing amino groups such as dimethylaminoethyl methacrylate and diethylaminoethyl methacrylate Vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, vinyltris (β-methoxyethoxy) silane, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane, vinyldimethylmethoxysilane, vinyldimethylethoxysilane,

Alkoxysilyl group-containing monomers such as 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, and 3-methacryloxypropylmethyldiethoxysilane; Examples thereof include monomers having two or more unsaturated bonds in one molecule, such as diallyl phthalate, divinylbenzene, allyl acrylate, and trimethylolpropane trimethacrylate.

As the emulsifier used in the present invention, any of anionic, cationic and nonionic emulsifiers can be used without particular limitation as long as they are generally used for emulsion polymerization. However, among these, only typical ones are exemplified. First, as the anionic emulsifier, higher alcohol sulfate, alkylbenzene sulfonate, polyoxyalkylene alkylphenyl ether sulfate, dialkyl succinate, etc. Sulfonic acid salts, alkyl diphenyl ether disulfonates, etc.
Examples of the nonionic emulsifier include polyoxyalkylene alkyl ethers and polyoxyalkylene alkyl phenyl ethers, and one or a mixture of two or more of them can be used.

The radical polymerization initiator used in the present invention is not particularly limited.
Among them, especially typical ones are exemplified, and potassium persulfate, sodium persulfate, ammonium persulfate, azobisisobutyronitrile or its hydrochloride, hydrogen peroxide, tertiary butyl hydroperoxide , Cumene hydroperoxide or benzoyl peroxide.

It is also possible to use a reducing agent together with the radical polymerization initiator described above. Only typical representative examples of the reducing agent that can be used at this time are sodium sulfoxylate formaldehyde, sodium pyrosulfite, L-ascorbic acid, and the like.

The solid content after hydrolysis and condensation of the non-radical polymerizable organic silicon compound used in the present invention is preferably in the range of 1% by weight to 50% by weight of the solid content in the aqueous resin emulsion. . Within this range, the production of the aqueous resin emulsion can be favorably performed, and the resulting aqueous resin emulsion coating film has excellent water resistance and weather resistance. It is more preferably in the range of 5% by weight or more and 30% by weight or less, and a coating film of an aqueous resin emulsion having further excellent water resistance and weather resistance can be obtained.

It is preferable that the amount of the light stabilizer used in the present invention is not less than 0.1% by weight and not more than 5% by weight of the solid content in the aqueous resin emulsion. Within this range, the compatibility between the aqueous resin emulsion and the light stabilizer will not be impaired, and the weather resistance of the resulting aqueous resin emulsion coating film will be excellent. More preferably 0.5
Weight% or more and 5 weight% or less,
It is more preferably in the range of 1% by weight or more and 5% by weight or less, still more preferably in the range of 2% by weight or more and 5% by weight or less. The resulting aqueous resin emulsion can be obtained.

Of the production methods according to the present invention, only typical ones will be exemplified, and the following methods are exemplified, but they are listed as particularly desirable methods.

That is, a mixture of radically polymerizable unsaturated monomers is added to ion-exchanged water in which an emulsifier is dissolved to obtain a pre-emulsion. Thereafter, ion-exchanged water is charged into the reaction vessel, and the temperature in the vessel is raised to 80 ° C. After the temperature is raised, a part of the pre-emulsion is charged, then a part of the aqueous solution of the radical polymerization initiator is added, and the mixture is stirred for 20 to 30 minutes. Thereafter, the rest of the pre-emulsion and the rest of the aqueous solution of the radical polymerization initiator are added dropwise over 2 to 5 hours. Stir for 1 to 2 hours after completion of the dropping. Thereafter, cooling and neutralization are performed. Then, a non-radical polymerizable organic silicon compound in which a light stabilizer is dissolved is dropped and stirred for 30 minutes to 2 hours to obtain a desired aqueous resin emulsion.

The aqueous resin emulsion of the present invention comprises:
It is useful as a resin for paints, especially as a paint for architectural exterior paints, which require particularly high water resistance and weather resistance, and as a coating material for various building materials.

[0030]

EXAMPLES The present invention will be described in detail with reference to examples below, but the present invention is not limited to the following examples. The following parts and percentages are all based on weight.

Examples 1-4, Comparative Examples 1-4 (1) Aqueous resin emulsion 150 parts of cyclohexyl methacrylate (hereinafter abbreviated as CHMA) and n-butyl methacrylate (hereinafter N)
Abbreviated as BMA. ), 115 parts of methyl methacrylate (hereinafter abbreviated as MMA), 125 parts of butyl acrylate (hereinafter abbreviated as BA), and 10 parts of acrylic acid (hereinafter abbreviated as AA). And A-17
4 (manufactured by Nippon Unicar Co., Ltd., 3-methacryloxypropyltrimethoxysilane) was mixed with 2.5 parts of a monomer mixture solution using Levenol WZ (manufactured by Kao Corporation, sodium polyoxyethylene nonyl phenyl ether sulfate). Active ingredient = 2
6%) and 2.5 parts of Neugen EA170S (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., polyoxyethylene nonylphenyl ether, active ingredient = 80%) are added to 100 parts of ion-exchanged water. To obtain a pre-emulsion.

Thereafter, 500 parts of ion-exchanged water is charged into a 2 liter reaction vessel equipped with a stirrer, a thermometer, a cooler and a dropping funnel, and the temperature in the kettle is raised to 80 ° C. while stirring while introducing nitrogen gas. did. After the temperature was raised, 5% of the pre-emulsion was charged, and then 20% of an aqueous ammonium persulfate solution in which 0.5 part of ammonium persulfate was dissolved in 30 parts of ion-exchanged water was added, followed by stirring at 80 ° C. for 20 minutes. Thereafter, 95% of the pre-emulsion and 80% of the aqueous ammonium persulfate solution were separately added dropwise over 4 hours. After completion of the dropwise addition, the mixture was stirred at 80 ° C. for 90 minutes. Thereafter, the mixture was cooled to 25 ° C. and neutralized with aqueous ammonia.

Next, 10 parts of SANOL LS-765 was dissolved in 100 parts of methyltrimethoxysilane, and this solution was added dropwise over 1 hour. Thereafter, the mixture was stirred for 1 hour to obtain a desired aqueous resin emulsion. The above aqueous resin emulsion exhibited the following properties. Solid content: 45.7%, viscosity: 680 mPa · s, pH: 8.4, volume average particle size:
123 nm. The particle size was measured using "Microtrack Particle Size Analyzer 9340-UPA" manufactured by Nikkiso Co., Ltd.

Assuming that the above is Example 1, the composition of the pre-emulsion, the non-radical polymerizable organosilicon compound and the light stabilizer were changed as shown in Tables 1 and 2 below. Emulsion polymerization was performed in the same manner as in Example 1 to synthesize an aqueous resin emulsion.

[0035]

[Table 1]

[0036]

[Table 2]

[0037]

[Table 3]

[0038]

[Table 4]

(2) Formulation of paint A water-based paint was obtained with the following formulation using the above-mentioned aqueous resin emulsion.

[0040]

[Table 5]

(3) Evaluation of paint The above water-based paint was applied to a slate plate by brush, and
A test plate was prepared by heating and drying for 0 minutes, and a water resistance test and a weather resistance test were performed. Table 5 shows the evaluation results. In addition, the evaluation method was performed by the following method.

Water resistance The test plate was immersed in tap water at 40 ° C. for 30 days, and evaluated visually by the following five steps. 5 points: no swelling and no glossiness 4 points: a little small swelling 3 points: small swelling, slight glossiness 2 points: medium swelling, glossiness 1 point:
Almost the entire surface is swollen and the gloss is large.

Weather resistance Sunshine weatherometer (manufactured by Suga Test Instruments Co., Ltd.)
The weather resistance test was performed for 4000 hours using S80), and
The 0 ° specular gloss value was measured. This specular gloss value after the test was divided by that before the test, and this value was calculated as a gloss retention. The test conditions are as follows. Black panel temperature: 63
° C, watering cycle: 18 min / 120 min.

[0044]

[Table 6]

[0045]

According to the present invention, it is possible to provide an aqueous resin emulsion which is useful as a resin for paints, especially as a resin for building exterior paints and various coating materials for building materials which require particularly high water resistance and weather resistance. .

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) C09D 133/10 C09D 133/10 157/00 157/00 183/04 183/04 F term (Reference) 4J002 BB02W BB11W BC02W BC08W BC09W BD03W BD10W BD14W BF01W BF02W BG01W BG03W BG04W BG05W BG07W BG10W BG12W BH00W BQ00W CP03X EU076 FD046 GH01 HA07 4J038 CA021 CA022 CB031 CB032 CB091 CB092 CC021 CC022 CC071 CC072 CD021 CD022 CD081 CD082 CD111 CD112 CE051 CE052 CF021 CF022 CG131 CG132 CG141 CG142 CG161 CG162 CG171 CG172 CH031 CH032 CH041 CH042 CH071 CH072 CH121 CH122 CH201 CH202 CK031 CK032 CL011 CL012 DL031 DL032 DL111 DL112 DL121 DL122 JB30 KA09 MA08 MA10 NA03 NA04 PA18 PB05 PC04 PC06

Claims (6)

[Claims] 1. An emulsion polymerization of a radically polymerizable unsaturated monomer in an aqueous medium, followed by the formula (R ¹ ) _n -Si- (R ² ) _{4-n wherein} n is an integer of 1 to 3 . R ¹ is an alkyl group having ¹ to 16 carbon atoms,
Cycloalkyl group, an aryl group,: R ² is in addition 1-8 alkoxy group having a carbon atom, a non-radical polymerizable organosilicon compound when the hydrolytic condensation simultaneously light stabilizer represented by a hydroxyl group] to obtain Aqueous resin emulsion. 2. A formula (R ¹ ) _n -Si- (R ² ) _{4-n wherein a} radical polymerizable unsaturated monomer is emulsion-polymerized in an aqueous medium and then a light stabilizer is dissolved. Where n is an integer of 1 to 3. R ¹ is an alkyl group having ¹ to 16 carbon atoms, a cycloalkyl group, an aryl group, R ² is an alkoxy group having 1 to 8 carbon atoms,
An aqueous resin emulsion obtained by subjecting a non-radical polymerizable organic silicon compound represented by the formula [hydroxyl group] to hydrolysis and condensation. 3. The aqueous resin emulsion according to claim 1, wherein the solid content of the non-radical polymerizable organic silicon compound is 1 to 50% by weight of the solid content in the aqueous resin emulsion. 4. The aqueous resin emulsion according to claim 1, wherein the light stabilizer is 0.1 to 5% by weight of the solid content in the aqueous resin emulsion. 5. The aqueous resin emulsion according to claim 1, wherein the light stabilizer is a hindered amine type. 6. The radical polymerizable unsaturated monomer of 30 to 7
The aqueous resin emulsion according to any one of claims 1 to 5, wherein 0% by weight is an alkyl methacrylate having an alkyl group having 4 or more carbon atoms.