JPH083418A - Water-based crosslinkable polymer latex and coating composition prepared using said latex - Google Patents

Abstract

PURPOSE:To provide a polymer latex improved in gloss, water resistance, etc., of a coating film thereof by previously polymerizing a monomer component having a larger total amt. of a carboxyl. group-contg. monomer and a hydroxyl. group-contg. monomer in production of a polymer latex through multistage polymn. CONSTITUTION:1-20%, ethylenically unsatd. monomer contg. a carboxyl group (e.g. acrylic acid) is mixed with 2-30% ethylenically unsatd. monomer contg. a hydroxyl group (e.g. hydroxyethyl. acrylate) and 97-50%, other ethylenically unsatd. monomer (e.g. styrene), provided that the total amt. thereof is 100%, whereby a monomer component A is prepd. Subsequently, the monomer component A is polymerized in a stage of polymn. other than the last stage. Subsequently, a monomer component B comprising an ethylenically unsatd. monomer contg. a carboxyl group and an ethylenically unsatd. monomer contg. a hydroxyl group, the total amt. of which is smaller than that of the monomer component A, is polymerized to obtain a polymer latex. This polymer latex is esp. useful for production of a crosslinkable coating which can be crosslinked using a crosslinking agent.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention is applicable to gloss, sharpness, water resistance,
The present invention relates to a method for producing a polymer latex capable of forming a coating film having excellent properties in coating film physical properties such as hardness, flex resistance, adhesion and impact resistance. The polymer latices produced according to the present invention are useful in paints, especially cross-linkable paints which can be cross-linked by the use of cross-linking agents.

[0002]

2. Description of the Related Art With the increasing demand for solvent-free paints, various water-based paints are being actively researched. Generally, in a cross-linking paint that reacts with a cross-linking agent under a baking condition, a hydrophilic organic solvent is used. A resin mainly composed of an aqueous resin obtained by neutralizing and polymerizing the resin polymerized in (1) is used. As compared with the aqueous resin, as the latex obtained by emulsion polymerization, a resin having a high molecular weight or a resin having a crosslinked structure in advance can be used, and therefore excellent physical properties are obtained for a coating film formed well. On the other hand, due to the fact that the resin is a heterogeneous substance that is dispersed in water in a certain size, even if it is reacted with a crosslinking agent, a dense and smooth coating film cannot be obtained or water resistance However, the pigment dispersibility was not sufficient, so the gloss and image clarity were poor, the balance between hardness and flex resistance was poor, and there were problems with the rheology of the paint.

[0003]

DISCLOSURE OF THE INVENTION The present invention solves the drawbacks of water-based paints containing such polymer latex as a main component, and provides gloss, sharpness, water resistance, hardness, flex resistance, adhesion and resistance. It is intended to provide a polymer latex excellent in impact resistance and rheology suitability.

[0004]

Means for Solving the Problems As a result of intensive studies by the present inventors, the above-mentioned problems were solved by imparting a polymer phase having a specific composition and physical properties to a polymer latex particle under specific conditions. The inventors have found that they can be solved and completed the present invention. That is, the present invention is a polymer latex produced by multistage polymerization, wherein the carboxyl group-containing ethylenically unsaturated monomer is 1 to 20%, the hydroxyl group-containing ethylenically unsaturated monomer is 2 to 30%, and other Polymerizing the monomer component [A] having 50 to 97% of the ethylenically unsaturated monomer (provided that the total amount of the monomers is 100% by weight) as an essential component as a polymerization step other than the last step, Then, the weight% of the carboxyl group-containing ethylenically unsaturated monomer and the hydroxyl group-containing ethylenically unsaturated monomer
The present invention relates to a polymer latex characterized by polymerizing a monomer component [B] having a total value smaller than that of the monomer component [A].

In addition, the total of the weight percentages of the carboxyl group-containing ethylenically unsaturated monomer and the hydroxyl group-containing ethylenically unsaturated monomer of the above monomer component [A] is the above monomer component [B]. 2. The polymer latex according to claim 1, which is 1.5 times or more of the total weight% of the carboxyl group-containing ethylenically unsaturated monomer and the hydroxyl group-containing ethylenically unsaturated monomer.

Further, it relates to a coating composition containing the above-mentioned latex and a crosslinking agent having reactivity with a carboxyl group and / or a hydroxyl group. Then, the present invention relates to a coating composition in which 2 to 50% of the water-soluble resin is mixed with the above-mentioned latex when the total of the latex and the water-soluble resin is 100% by weight. The production of the polymer latex in the present invention is carried out by so-called multistage polymerization in which a plurality of monomer components are polymerized in separate stages in emulsion polymerization. The monomer component [A] is, for example, two-stage polymerization. In the case of, the polymerization is conducted as the first stage, and in the case of three-stage polymerization, the polymerization is conducted as the first stage or the second stage. In this production method, so-called phase transfer polymerization is designed such that the polymer phase of the monomer component [A] is present near the surface of the latex particles after all the polymerization steps are completed.

In order to cause a phase transition in multistage polymerization, it is necessary that the difference in molecular weight and polarity between the polymer located on the surface of the particle and the polymer located inside the particle due to the phase transition is designed accordingly. In the invention, the total of the weight% of the carboxyl group-containing ethylenically unsaturated monomer and the hydroxyl group-containing ethylenically unsaturated monomer in the monomer component [A] is higher than that of the monomer component [A]. Of the carboxyl group-containing ethylenically unsaturated monomer and the hydroxyl group-containing ethylenically unsaturated monomer in the monomer component to be polymerized in the step of More than double. The total of the weight% of the carboxyl group-containing ethylenically unsaturated monomer and the hydroxyl group-containing ethylenically unsaturated monomer in the monomer component [A] is the carboxyl group-containing ethylene in the monomer component [B]. If the total amount of the unsaturated unsaturated monomer and the hydroxyl group-containing ethylenically unsaturated monomer is less than the total, it becomes difficult to cause the phase transfer polymerization.

Since the polymer phase of the monomer component [A] is present on the surface of the latex particles after polymerization, the monomer component [A]
It is generally practiced to produce a latex by using as a final stage in a multi-stage polymerization, but a latex is produced by a so-called phase transfer polymerization method in which the monomer component [A] is used as a polymerization stage other than the final stage. When used as a film, the water resistance is excellent. The ratio of the polymer obtained from the monomer component [A] is preferably 5% to 70%, and more preferably 10% to 50% when the weight of the total polymer is 100%.

The monomer component [A] is 1 to 20% of a carboxyl group-containing ethylenically unsaturated monomer, 2 to 30% of a hydroxyl group-containing ethylenically unsaturated monomer and other ethylenically unsaturated monomers. 50 to 97% (however, the total amount of monomers is 100% by weight), but preferably 2 to 15% of a carboxyl group-containing ethylenically unsaturated monomer,
Hydroxyl group-containing ethylenically unsaturated monomer 3-25%
And 60 to 95% of other ethylenically unsaturated monomers, more preferably 3 to 10% of carboxyl group-containing ethylenically unsaturated monomers, 5 to 20% of hydroxyl group-containing ethylenically unsaturated monomers, and It is composed of 70 to 92% of other ethylenically unsaturated monomers. When the carboxyl group-containing ethylenically unsaturated monomer is less than 1% or the hydroxyl group-containing ethylenically unsaturated monomer is less than 2%, the polymerization stability is lowered, or a coating film containing a pigment is prepared. In that case, the balance between gloss and sharpness, and hardness and bending resistance is reduced. Further, when the carboxyl group-containing ethylenically unsaturated monomer exceeds 20% or the hydroxyl group-containing ethylenically unsaturated monomer exceeds 30%, the polymerization stability is deteriorated, or when a coating film is formed. Weather resistance and water resistance decrease.

The polymer obtained from the monomer component [A] existing near the surface of the particles by the phase transition polymerization is swollen in water to an extent according to the design by neutralizing a part or all of the carboxyl groups. Alternatively, it takes a form in which it dissolves, which improves the rheological suitability of the coating material and improves the gloss and smoothness of the coating film and the balance between hardness and flex resistance. Further, also in the case of a coating composition containing a pigment, a coating composition having excellent gloss and sharpness can be obtained.

The carboxyl group-containing ethylenically unsaturated monomer used in the monomer component [A] is acrylic acid, methacrylic acid, itaconic acid, fumaric acid, maleic acid, crotonic acid, maleic anhydride, and Itaconic acid, maleic acid half ester, etc. can be used, and as the hydroxyl group-containing ethylenically unsaturated monomer, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, hydroxycyclohexyl (meth ) Acrylate, 4-hydroxybutyl vinyl ether, and a half ester of the above hydroxyl group-containing monomer and a cyclic acid anhydride such as succinic anhydride can be used.

Other ethylenically unsaturated monomers include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, dodecyl (meth) acrylate and cyclohexyl (meth). ) (Meth) acrylic acid esters such as acrylate, aromatic monomers such as styrene, α-methylstyrene and vinyltoluene, vinyl esters such as vinyl acetate, vinyl propionate and vinyl persate, ethyl vinyl ether, butyl vinyl ether , Vinyl ethers such as cyclohexyl vinyl ether, vinyl cyanides such as (meth) acrylonitrile, vinyl chloride, vinylidene chloride, vinylidene fluoride, tetrafluoroethylene, chlorotrifluoroethylene, hexa There are vinyl halides such as fluoropropylene, ethylenically unsaturated monomers having sulfonic acid groups or sulfuric acid ester groups such as styrene sulfonate and allyl sulfosuccinate, and butadiene. Body such as (meth) acrylamide, vinylpyrrolidone, acrolein, diacetone methacrylamide, methyl vinyl ketone, acid phosphooxyethyl methacrylate, 3-chloro-2-acid phosphooxyethyl methacrylate, (poly) oxyethylene mono (meth) Acrylate and diacetone methacrylate can be used. If necessary, a chain transfer agent such as dodecyl mercaptan can also be used. The various monomers exemplified above can be used alone or in combination of two or more.

The monomer constituting the polymerization stage other than the polymerization stage consisting of the monomer component [A] is a monomer component [A]
In addition to the carboxyl group-containing ethylenically unsaturated monomer, the hydroxyl group-containing ethylenically unsaturated monomer and the other ethylenically unsaturated monomer described as usable in the above, N-methylol acrylamide, N-butoxy Monomers with functional groups such as methyl acrylamide, (poly) propylene glycol (meth) acrylate, glycidyl (meth) acrylate, aryl glycidyl ether, vinylcyclohexene oxide, divinylbenzene, allyl (meth) acrylate, (poly) oxy One type or two or more types of crosslinkable monomers such as ethylene di (meth) acrylate and trimethylolpropane tri (meth) acrylate may be used in combination, if necessary. If necessary, a chain transfer agent such as dodecyl mercaptan can also be used.

The number of polymerization steps other than the polymerization step comprising the monomer component [A] may be one step depending on the target physical properties of the coating film, and the same or different single steps may be used to achieve a higher balance of physical properties. Two or more stages having a monomer composition can be used. For example, in the latex particles after the completion of all polymerization steps, by providing a relatively hard polymer phase inside the polymer phase composed of the monomer component [A] and further providing a soft polymer phase inside the polymer phase. It is possible to obtain a coating film having good hardness, flex resistance and impact resistance.

The production of the polymer latex by the multi-stage polymerization in the present invention can be carried out by a commonly used emulsion polymerization. Radical polymerization initiators are those that undergo radical decomposition by heat or reducing substances to cause addition polymerization of ethylenically unsaturated monomers, such as water-soluble or oil-soluble persulfates, peroxides, azobis compounds, etc. Is used. Specific examples include potassium persulfate, sodium persulfate, ammonium persulfate, hydrogen peroxide, t-butyl hydroperoxide, t-butyl peroxybenzoate, 2,2-azobisisobutyronitrile,
2,2-azobis (2-diaminopropane) hydrochloride, 2,2-azobis (2,4-dimethylvaleronitrile) and the like can be mentioned, and the amount thereof is usually the weight relative to the total amount of the monomers. 0.1% to 1%. When it is desired to accelerate the polymerization rate or to carry out the polymerization at a low temperature, a reducing agent such as sodium bisulfite, ferrous chloride, ascorbate, Rongalit or the like can be used in combination with the radical polymerization initiator.

As the surfactant, in addition to the ethylenically unsaturated monomer having a sulfonic acid group or a sulfuric acid ester group which is a reactive surfactant, ordinary fatty acid soap, alkyl sulfonate, alkyl sulfosuccinate, poly Anionic surfactants such as oxyethylene alkyl sulfate and polyoxyethylene alkylaryl sulfate, and nonionic surfactants and reactions such as polyoxyethylene alkylaryl ether, polyoxyethylene sorbitan fatty acid ester, and oxyethyleneoxypropylene block copolymer Nonionic surfactants copolymerizable with ethylenically unsaturated monomer called nonionic surfactants can be used alone or in combination of two or more. Considering water resistance when used as a coating film Reactive surface activity if Mainly it is preferable to use.

As a method of introducing the monomer components into the reaction system, each monomer or a mixture of each monomer can be directly introduced into the reaction system, or a homogenizer obtained by mixing with an aqueous medium and a surfactant. For example, a pre-emulsified product can be introduced. The average particle size of the polymer latex produced in the present invention is preferably smaller than 0.5 μ, more preferably smaller than 0.3 μ. When the average particle diameter is larger than 0.5 μ, it becomes difficult to improve the gloss when the pigment is mixed. The polymer latex obtained by the present invention has good dispersion stability without neutralizing the carboxyl group in the polymer latex, but in order to maintain dispersion stability for a long period of time, for example, ammonia, sodium hydroxide, It is preferable to adjust the pH within the range of 5 to 10 using potassium hydroxide or amines.

Examples of the cross-linking agent having reactivity with a carboxyl group and / or a hydroxyl group used in the present invention include melamine resins, blocked isocyanate compounds, polyepoxides, compounds having a plurality of oxazoline groups, and a plurality of aziridine groups. The compound or the like may be used alone or in combination of two or more, and the amount thereof is preferably 2 parts to 50 parts, more preferably 5 parts to 3 parts based on 100 parts by weight of the base resin.
5 copies. These cross-linking agents are usually added as one component of the coating composition when they are prepared, but it is also possible to add some or all of them to various monomers during the production of the polymer latex.

Examples of the water-soluble resin used in the present invention include water-soluble acrylic resins having a carboxyl group and / or a hydroxyl group, polyester resins, alkyd resins, etc., which can be produced by ordinary methods or are generally available. It is used to further improve the gloss, sharpness and smoothness of a coated film. The amount used is 2 to 50%, preferably 5% to 50%, based on the total weight of the polymer latex as 100%. When the amount of the water-soluble resin used is less than 2%, further improvement in gloss, image clarity and smoothness when formed into a coating film is insufficient, and when it exceeds 50%, the fluidity of the coating composition decreases. Among the water-soluble resins, acrylic resin is preferably used, and a silicone compound having an ethylenically unsaturated bond can be copolymerized to further improve weather resistance and stain resistance. Further, as the water-soluble acrylic resin, those produced by solution polymerization and made water-soluble can be used, and those produced by emulsion polymerization and made water-soluble can also be used.

In the coating composition of the present invention, the components usually added to the aqueous coating composition, such as a thickener, a defoaming agent, a film-forming aid,
It is optional to add a pigment, a dispersant, a wetting agent, a dye, a preservative and the like.

[0021]

EXAMPLES Next, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. In addition, "part" and "%" in the examples are based on weight unless otherwise stated. The coating film was prepared and evaluated by the following methods, and the evaluation results of the coating films prepared in the respective examples and comparative examples are summarized in Table 1. (Coating liquid formulation) Resin mixture (nonvolatile content 45%) 100 parts Texanol (Note 1) 2.25 parts Pigment dispersion (nonvolatile content 71%) 50 parts Thickener (nonvolatile content 10%, Note 2) 3.3 Part (Note 1) 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate (Note 2) UH-438 manufactured by Asahi Denka Kogyo Co., Ltd. (compounded with pigment dispersion) water 10.81 parts dispersant (Note 3) 1.06 parts 25% aqueous ammonia 0.06 parts Propylene glycol 2.43 parts Defoamer (Note 4) 0.15 parts Titanium oxide (Note 5) 35.49 parts (Note 3) Kao Corporation ) Poise 530 (Note 4) San Nopco SN-Defomemer3
82 (Note 5) Typake R-930 manufactured by Ishihara Sangyo Co., Ltd.

(Conditions for preparing coating film) After coating on various substrates with a 101μ applicator and predrying at 80 # C for 10 minutes, a system using melamine resin as a crosslinking agent was 130 # C,
The system using the blocked isocyanate compound was baked at 150 ° C for 30 minutes. (Gloss value) A coating film was formed on a glass plate having a thickness of 2 mm, and a value of 60 ° -60 ° was measured using a digital variable angle gloss meter manufactured by Suga Test Instruments Co., Ltd. (Hardness) Create a coating film on a glass plate with a thickness of 2 mm, and
Pendulum type hardness tester (BYK Chemi
Pendulum hardness test made by e
The König hardness was measured in r). (Bending resistance) A coating film was formed on a tin plate having a thickness of 0.1 mm, and a 2φ / 180 ° bending test was performed in a 20 ° C constant temperature room to visually evaluate the presence or absence of abnormalities. ○: crack,
No abnormalities in peeling, x: Abnormal. (Water resistance) Create a coating film on a glass plate with a thickness of 2 mm and
The sample was immersed in distilled water in a water tank for 30 days in a 0 # C thermostatic chamber, and the change in appearance was visually evaluated. ◯: No change in cloudiness or whitening, Δ: slight change, ×: obvious change.

[0023]

Example 1 This example is a two-stage polymerization. Water 4 in a reaction vessel equipped with a stirrer, reflux condenser, dropping tank and thermometer.
59.3 parts, 7.2 parts of 25% reactive surfactant (SE-1025N manufactured by Asahi Denka Co., Ltd.) aqueous solution were added, and the internal temperature was adjusted to 8
Styrene 13.5 as the first stage while adjusting to 0 # C
Parts, methyl methacrylate 94.5 parts, butyl acrylate 121.5 parts, 2-hydroxyethyl methacrylate 27.0 parts, methacrylic acid 13.5 parts, n-dodecyl mercaptan 2.4 parts, 25% reactive surfactant ( Asahi Denka Co., Ltd. SE-1025N) aqueous solution 12.2 parts, 25
% Nonionic surfactant (Emulgen 92 manufactured by Kao Corporation)
0) 4.0 parts, 2% ammonium persulfate aqueous solution 33.8
Parts and 110.8 parts of water preliminarily emulsified with a homomixer were added over 60 minutes (5% by weight of a carboxyl group-containing ethylenically unsaturated monomer in a monomer component, a hydroxyl group-containing ethylenically unsaturated Monomer 10% by weight). While adjusting the internal temperature to 80 ° C, 45 minutes later, as a second step, 344.0 parts of methyl methacrylate, 266.0 parts of butyl acrylate, 9.0 parts of 2-hydroxyethyl methacrylate, 11.0 parts of methacrylic acid, 1.2 parts of trimethylolpropane triacrylate, 25% reactive surfactant (SE-1025N manufactured by Asahi Denka Co., Ltd.) aqueous solution 34.
0 part, 25% nonionic surfactant (Emulgen 920 manufactured by Kao Corporation) 14.4 parts, 2% ammonium persulfate aqueous solution 99.5 parts, water 263.8 parts pre-emulsified with a homomixer for 130 minutes. Was added over (1.7 in the monomer component, the carboxyl group-containing ethylenically unsaturated monomer 1.7
% By weight, 1.4% by weight of hydroxyl group-containing ethylenically unsaturated monomer). After adjusting the internal temperature to 80 ° C. for 90 minutes, cooling was started and 60.0 parts of water was added. After cooling, it was filtered with a 325 mesh filter and various properties were measured. As a result, the nonvolatile content was 46.0%, the pH was 2.1, the average particle size was 0.12μ, and this was 25%.
The pH was adjusted to 8.5 with aqueous ammonia. 25 parts of a non-volatile content of a melamine resin (CYMEL 370 manufactured by Mitsui Cyanamid Co., Ltd.) was mixed with 100 parts of the non-volatile content of the latex obtained here to adjust the non-volatile content to 45%. A coating liquid was prepared as a resin mixture, and a coating film was prepared according to the above conditions.

[0024]

Example 2 A water-soluble acrylic resin having an acid value of 31, a hydroxyl value of 69, a weight average molecular weight of 5500, a calculated Tg of 50 #C and a pH of 8.5 was added to 80 parts of the nonvolatile content of the latex obtained in Example 1 as a nonvolatile content. 20 parts of the melamine resin used in Example 1 was mixed with 25 parts of the non-volatile content to adjust the non-volatile content to 45% to prepare a coating solution as a resin mixture in the above-mentioned coating solution formulation, which was applied according to the above conditions. The membrane was created.

[0025]

Example 3 This example is a three-stage polymerization. Water 4 in a reaction vessel equipped with a stirrer, reflux condenser, dropping tank and thermometer.
59.3 parts, 7.2 parts of 25% reactive surfactant (SE-1025N manufactured by Asahi Denka Co., Ltd.) aqueous solution were added, and the internal temperature was adjusted to 8
Styrene 13.5 as the first stage while adjusting to 0 # C
Parts, methyl methacrylate 94.5 parts, butyl acrylate 121.5 parts, 2-hydroxyethyl methacrylate 27.0 parts, methacrylic acid 13.5 parts, n-dodecyl mercaptan 2.4 parts, 25% reactive surfactant ( Asahi Denka Co., Ltd. SE-1025N) aqueous solution 12.2 parts, 25
% Nonionic surfactant (Emulgen 92 manufactured by Kao Corporation)
0) 5.0 parts, 2% ammonium persulfate aqueous solution 20.3
And 109.8 parts of water were pre-emulsified with a homomixer over 60 minutes (5% by weight of carboxyl group-containing ethylenically unsaturated monomer in the monomer component, hydroxyl group-containing ethylenically unsaturated Monomer 10% by weight). While adjusting the internal temperature to 80 ° C., 45 minutes later, as the second step, 218.4 parts of methyl methacrylate, 226.0 parts of butyl acrylate, 5.6 parts of methacrylic acid, 1.2 parts of trimethylolpropane triacrylate, 25% reactive surfactant (SE-1025N manufactured by Asahi Denka Co., Ltd.) aqueous solution 2
7.0 parts, 25% nonionic surfactant (Emulgen 920, manufactured by Kao Corporation) 14.4 parts, 2% ammonium persulfate aqueous solution 81.0 parts, water 152.6 parts pre-emulsified with a homomixer Added over 90 minutes (carboxyl group-containing ethylenically unsaturated monomer 1.
2% by weight, hydroxyl group-containing ethylenically unsaturated monomer 0% by weight). While adjusting the internal temperature to 80 ° C, 45 minutes later, as the third step, methyl methacrylate 125.6 was used.
Parts, butyl acrylate 40.0 parts, 2-hydroxyethyl methacrylate 9.0 parts, methacrylic acid 5.4 parts,
25% reactive surfactant (SE-102 manufactured by Asahi Denka Co., Ltd.)
5N) 6.0 parts of aqueous solution, 1.2 parts of 25% nonionic surfactant (Emulgen 920 manufactured by Kao Corporation), 32.0 parts of 2% ammonium persulfate aqueous solution, and 110.0 parts of water are pre-emulsified by a homomixer. Was added over 45 minutes (3% by weight of the carboxyl group-containing ethylenically unsaturated monomer and 5% by weight of the hydroxyl group-containing ethylenically unsaturated monomer in the monomer components). After adjusting the internal temperature to 80 ° C. for 90 minutes, cooling was started and 60.0 parts of water was added. After cooling, it was filtered through a 325 mesh filter and various properties were measured. As a result, the nonvolatile content was 46.0%, the pH was 2.2, and the average particle size was 0.12μ.
The pH was adjusted to 8.5 with aqueous ammonia. A coating solution was prepared under the same conditions as in Example 2 except that the latex obtained here was used, and a coating film was prepared according to the above conditions.

[0026]

Example 4 Instead of the melamine resin used in Example 3, a blocked isocyanate compound (T manufactured by Asahi Kasei Kogyo Co., Ltd.) was used.
A coating solution was prepared under the same conditions as in Example 3 except that (PA-B80E aqueous dispersion) was used, and a coating film was prepared according to the above conditions.

[0027]

Example 5 This example is a three-stage polymerization. Water 4 in a reaction vessel equipped with a stirrer, reflux condenser, dropping tank and thermometer.
59.3 parts, 7.2 parts of 25% reactive surfactant (SE-1025N manufactured by Asahi Denka Co., Ltd.) aqueous solution were added, and the internal temperature was adjusted to 8
While adjusting to 0 # C, as the first step, 218.4 parts of methyl methacrylate, 226.0 parts of butyl acrylate, 5.6 parts of methacrylic acid, 1.2 parts of trimethylolpropane triacrylate, 25% reactive surfactant. (SE-1025N manufactured by Asahi Denka Co., Ltd.) 27.0 parts of aqueous solution, 25%
Nonionic surfactant (Emulgen 92 manufactured by Kao Corporation)
0) 14.4 parts, 2% ammonium persulfate aqueous solution 81.
What was pre-emulsified with 0 part and 152.6 parts of water with a homomixer was added over 90 minutes (1.2% by weight of a carboxyl group-containing ethylenically unsaturated monomer in a monomer component, a hydroxyl group-containing ethylene. 0% by weight of unsaturated monomer). While adjusting the internal temperature to 80 ° C., 45 minutes later, 13.5 parts of styrene and 94.
5 parts, butyl acrylate 121.5 parts, 2-hydroxyethyl methacrylate 27.0 parts, methacrylic acid 1
3.5 parts, n-dodecyl mercaptan 2.4 parts, 25%
Reactive surfactant (SE-1025N manufactured by Asahi Denka Co., Ltd.)
Preliminary emulsification of 12.2 parts of an aqueous solution, 5.0 parts of 25% nonionic surfactant (Emulgen 920 manufactured by Kao Corporation), 20.3 parts of a 2% aqueous solution of ammonium persulfate, and 109.8 parts of water with a homomixer. Was added over 60 minutes (5% by weight of a carboxyl group-containing ethylenically unsaturated monomer and 10% by weight of a hydroxyl group-containing ethylenically unsaturated monomer in the monomer components). 45 while adjusting the internal temperature to 80 ℃
After 3 minutes, methyl methacrylate 125.
6 parts, butyl acrylate 40.0 parts, 2-hydroxyethyl methacrylate 9.0 parts, methacrylic acid 5.4
Part, 25% reactive surfactant (SE-1 manufactured by Asahi Denka Co., Ltd.
0.25N) 6.0 parts of aqueous solution, 1.2 parts of 25% nonionic surfactant (Emulgen 920 manufactured by Kao Corporation), 32.0 parts of 2% ammonium persulfate aqueous solution, and 111.0 parts of water are pre-emulsified with a homomixer. The obtained product was added over 45 minutes (3% by weight of a carboxyl group-containing ethylenically unsaturated monomer and 5% by weight of a hydroxyl group-containing ethylenically unsaturated monomer in the monomer components). After adjusting the internal temperature to 80 ° C. for 90 minutes, cooling was started and 60.0 parts of water was added. After cooling, filter with a 325 mesh filter,
When various properties were measured, nonvolatile content was 46.1%, pH
Is 2.2 and the average particle size is 0.11μ.
The pH was adjusted to 8.5 with aqueous ammonia. A coating solution was prepared under the same conditions as in Example 2 except that the latex obtained here was used, and a coating film was prepared according to the above conditions.

[0028]

Comparative Example 1 This example is a two-stage polymerization. Water 4 in a reaction vessel equipped with a stirrer, reflux condenser, dropping tank and thermometer.
59.3 parts, 7.2 parts of 25% reactive surfactant (SE-1025N manufactured by Asahi Denka Co., Ltd.) aqueous solution were added, and the internal temperature was adjusted to 8
While adjusting to 0 # C, as the first step, 344.0 parts of methyl methacrylate, 266.0 parts of butyl acrylate, 2
-Hydroxyethyl methacrylate 9.0 parts, methacrylic acid 11.0 parts, trimethylolpropane triacrylate 1.2 parts, 25% reactive surfactant (Asahi Denka Co., Ltd.)
SE-1025N) aqueous solution 34.0 parts, 25% nonionic surfactant (Kao Corporation Emulgen 920) 1
4.4 parts, 2% ammonium persulfate aqueous solution 108.0
And 263.8 parts of water, which had been pre-emulsified with a homomixer, were added over 130 minutes (1.7% by weight of a carboxyl group-containing ethylenically unsaturated monomer in a monomer component, a hydroxyl group-containing ethylenic Unsaturated monomer 1.4% by weight). While adjusting the internal temperature to 80 ° C., 45 minutes later, as the second step, 13.5 parts of ethylene, 94.5 parts of methyl methacrylate, 121.5 parts of butyl acrylate, 2-
27.0 parts of hydroxyethyl methacrylate, 13.5 parts of methacrylic acid, 2.4 parts of n-dodecyl mercaptan,
25% reactive surfactant (SE-102 manufactured by Asahi Denka Co., Ltd.)
5N) Aqueous solution 12.2 parts, 25% nonionic surfactant (Emulgen 920 manufactured by Kao Corporation) 4.0 parts, 2% ammonium persulfate aqueous solution 25.3 parts, and water 110.8 parts were pre-emulsified with a homomixer. The obtained product was added over 60 minutes (5% by weight of a carboxyl group-containing ethylenically unsaturated monomer and 10% by weight of a hydroxyl group-containing ethylenically unsaturated monomer in the monomer components). After adjusting the internal temperature to 80 ° C. for 90 minutes, cooling was started and 60.0 parts of water was added. After cooling, filter with a 325 mesh filter,
When various properties were measured, nonvolatile content was 45.9%, pH
Is 2.0 and the average particle size is 0.14μ.
The pH was adjusted to 8.5 with aqueous ammonia. A coating solution was prepared under the same conditions as in Example 2 except that the latex obtained here was used, and a coating film was prepared according to the above conditions.

[0029]

Comparative Example 2 This example is a one-step polymerization. Water 4 in a reaction vessel equipped with a stirrer, reflux condenser, dropping tank and thermometer.
59.3 parts, 7.2 parts of 25% reactive surfactant (SE-1025N manufactured by Asahi Denka Co., Ltd.) aqueous solution were added, and the internal temperature was adjusted to 8
While adjusting to 0 # C, styrene 13.5 parts, methyl methacrylate 438.5 parts, butyl acrylate 387.5
Parts, 2-hydroxyethyl methacrylate 36.0 parts,
Methacrylic acid 24.5 parts, trimethylolpropane triacrylate 1.2 parts, n-dodecyl mercaptan 2.
4 parts, 25% reactive surfactant (SE- manufactured by Asahi Denka Co., Ltd.
1025N) aqueous solution 46.2 parts, 25% nonionic surfactant (Emulgen 920 manufactured by Kao Corporation) 18.4 parts,
23.3% ammonium persulfate aqueous solution 133.3 parts, water 37
7.8 parts of which was pre-emulsified with a homomixer were added over 190 minutes (2.7% by weight of a carboxyl group-containing ethylenically unsaturated monomer in a monomer component, a hydroxyl group-containing ethylenically unsaturated monomer). 4% by weight). After adjusting the internal temperature to 80 ° C. for 90 minutes, cooling was started and 60.0 parts of water was added. After cooling, it was filtered with a 325 mesh filter and various properties were measured. As a result, the nonvolatile content was 45.8%, the pH was 2.1, the average particle size was 0.12μ, and the pH was adjusted to 8 with 25% ammonia water. Adjusted to .5. A coating solution was prepared under the same conditions as in Example 2 except that the latex obtained here was used, and a coating film was prepared according to the above conditions.

[0030]

Comparative Example 3 This example is a one-step polymerization. Water 4 in a reaction vessel equipped with a stirrer, reflux condenser, dropping tank and thermometer.
59.3 parts, 7.2 parts of 25% reactive surfactant (SE-1025N manufactured by Asahi Denka Co., Ltd.) aqueous solution were added, and the internal temperature was adjusted to 8
While adjusting to 0 # C, styrene 13.5 parts, methyl methacrylate 519.5 parts, butyl acrylate 306.5
Parts, 2-hydroxyethyl methacrylate 36.0 parts,
Methacrylic acid 24.5 parts, trimethylolpropane triacrylate 1.2 parts, n-dodecyl mercaptan 2.
4 parts, 25% reactive surfactant (SE- manufactured by Asahi Denka Co., Ltd.
1025N) aqueous solution 46.2 parts, 25% nonionic surfactant (Emulgen 920 manufactured by Kao Corporation) 18.4 parts,
23.3% ammonium persulfate aqueous solution 133.3 parts, water 37
7.8 parts of which was pre-emulsified with a homomixer were added over 190 minutes (2.7% by weight of a carboxyl group-containing ethylenically unsaturated monomer in a monomer component, a hydroxyl group-containing ethylenically unsaturated monomer). 4% by weight). After adjusting the internal temperature to 80 ° C. for 90 minutes, cooling was started and 60.0 parts of water was added. After cooling, it was filtered with a 325 mesh filter and various properties were measured. As a result, the nonvolatile content was 45.9%, the pH was 2.1, the average particle size was 0.11μ, and the pH was adjusted to 8 with 25% ammonia water. Adjusted to .5. A coating solution was prepared under the same conditions as in Example 2 except that the latex obtained here was used, and a coating film was prepared according to the above conditions.

[0031]

Comparative Example 4 This example is a two-stage polymerization. Water 4 in a reaction vessel equipped with a stirrer, reflux condenser, dropping tank and thermometer.
59.3 parts, 7.2 parts of 25% reactive surfactant (SE-1025N manufactured by Asahi Denka Co., Ltd.) aqueous solution were added, and the internal temperature was adjusted to 8
Styrene 13.5 as the first stage while adjusting to 0 # C
Parts, methyl methacrylate 104.1 parts, butyl acrylate 135.9 parts, 2-hydroxyethyl methacrylate 3.0 parts, methacrylic acid 13.5 parts, n-dodecyl mercaptan 2.4 parts, 25% reactive surfactant ( Asahi Denka Co., Ltd. SE-1025N) aqueous solution 12.2 parts, 25
% Nonionic surfactant (Emulgen 92 manufactured by Kao Corporation)
0) 4.0 parts, 2% ammonium persulfate aqueous solution 33.8
Parts and 110.8 parts of water preliminarily emulsified with a homomixer were added over 60 minutes (5% by weight of a carboxyl group-containing ethylenically unsaturated monomer in a monomer component, a hydroxyl group-containing ethylenically unsaturated Monomer 1.1% by weight). While adjusting the internal temperature to 80 ° C, 45 minutes later, as a second step, 344.0 parts of methyl methacrylate, 266.0 parts of butyl acrylate, 9.0 parts of 2-hydroxyethyl methacrylate, 11.0 parts of methacrylic acid, 1.2 parts of trimethylolpropane triacrylate, 25% reactive surfactant (SE-1025N manufactured by Asahi Denka Co., Ltd.) aqueous solution 3
4.0 parts, 25% nonionic surfactant (Emulgen 920 manufactured by Kao Corporation) 14.4 parts, 2% ammonium persulfate aqueous solution 99.5 parts, water 263.8 parts pre-emulsified with a homomixer The mixture was added over 130 minutes (1.7% by weight of carboxyl group-containing ethylenically unsaturated monomer and 1.4% by weight of hydroxyl group-containing ethylenically unsaturated monomer in the monomer components). After adjusting the internal temperature to 80 ° C. for 90 minutes, cooling was started and 60.0 parts of water was added. After cooling, it was filtered with a 325 mesh filter and various properties were measured. As a result, the nonvolatile content was 45.8%, the pH was 2.1, and the average particle size was 0.15μ.
The pH was adjusted to 8.5 with aqueous ammonia. A coating solution was prepared under the same conditions as in Example 2 except that the latex obtained here was used, and a coating film was prepared according to the above conditions.

[0032]

Comparative Example 5 This example is a two-stage polymerization. Water 4 in a reaction vessel equipped with a stirrer, reflux condenser, dropping tank and thermometer.
59.3 parts, 7.2 parts of 25% reactive surfactant (SE-1025N manufactured by Asahi Denka Co., Ltd.) aqueous solution were added, and the internal temperature was adjusted to 8
Styrene 13.5 as the first stage while adjusting to 0 # C
Parts, methyl methacrylate 64.5 parts, butyl acrylate 88.5 parts, 2-hydroxyethyl methacrylate 90.0 parts, methacrylic acid 13.5 parts, n-dodecyl mercaptan 2.4 parts, 25% reactive surfactant ( Asahi Denka Co., Ltd. SE-1025N) aqueous solution 12.2 parts, 25%
Nonionic surfactant (Emulgen 92 manufactured by Kao Corporation)
0) 4.0 parts, 2% ammonium persulfate aqueous solution 33.8
Parts and 110.8 parts of water preliminarily emulsified with a homomixer were added over 60 minutes (5% by weight of a carboxyl group-containing ethylenically unsaturated monomer in a monomer component, a hydroxyl group-containing ethylenically unsaturated 33% by weight of monomer). While adjusting the internal temperature to 80 ° C, 45 minutes later, as a second step, 344.0 parts of methyl methacrylate, 266.0 parts of butyl acrylate, 9.0 parts of 2-hydroxyethyl methacrylate, 11.0 parts of methacrylic acid, 1.2 parts of trimethylolpropane triacrylate, 25% reactive surfactant (SE-1025N manufactured by Asahi Denka Co., Ltd.) aqueous solution 34.
0 part, 25% nonionic surfactant (Emulgen 920 manufactured by Kao Corporation) 14.4 parts, 2% ammonium persulfate aqueous solution 99.5 parts, water 263.8 parts pre-emulsified with a homomixer for 130 minutes. Was added over (1.7 in the monomer component, the carboxyl group-containing ethylenically unsaturated monomer 1.7
% By weight, 1.4% by weight of hydroxyl group-containing ethylenically unsaturated monomer). After adjusting the internal temperature to 80 ° C. for 90 minutes, cooling was started and 60.0 parts of water was added. After cooling, it was filtered with a 325 mesh filter and various properties were measured. As a result, the nonvolatile content was 45.6%, the pH was 2.1, the average particle size was 0.11μ, and this was 25%.
The pH was adjusted to 8.5 with aqueous ammonia. A coating solution was prepared under the same conditions as in Example 2 except that the latex obtained here was used, and a coating film was prepared according to the above conditions.

[0033]

[Table 1]

[0034]

The coating composition using the polymer latex of the present invention has gloss, sharpness, water resistance, hardness, which cannot be provided by the conventional coating compositions using the polymer latex. It is possible to form a crosslinked coating film having excellent flex resistance, adhesion, impact resistance and the like.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Toyoaki Yamauchi Inventor, Toyoaki Yamazaki, Kawasaki-ku, Kanagawa Prefecture 1-3-1 Nocturnal Asahi Kasei Kogyo Co., Ltd.

Claims (4)

[Claims] 1. A polymer latex produced by multi-stage polymerization, comprising 1 to 20% of a carboxyl group-containing ethylenically unsaturated monomer, 2 to 30% of a hydroxyl group-containing ethylenically unsaturated monomer, and other Ethylenically unsaturated monomer 50-97% (however, the total weight of the monomers is 100
%)) As the essential component, and the monomer component [A] is polymerized as a polymerization step other than the last step, and then the carboxyl group-containing ethylenically unsaturated monomer and the hydroxyl group-containing ethylenically unsaturated monomer are added. A polymer latex characterized by polymerizing a monomer component [B] having a total weight% of the body smaller than that of the monomer component [A]. 2. The total of the weight% of the carboxyl group-containing ethylenically unsaturated monomer and the hydroxyl group-containing ethylenically unsaturated monomer of the monomer component [A] is the monomer component [B]. 2. The polymer latex according to claim 1, which is 1.5 times or more the total of the weight% of the carboxyl group-containing ethylenically unsaturated monomer and the hydroxyl group-containing ethylenically unsaturated monomer. 3. A coating composition containing the latex according to claim 1 or 2 and a crosslinking agent having reactivity with a carboxyl group and / or a hydroxyl group. 4. The latex according to claim 3, wherein the total amount of the latex and the water-soluble resin is 100% by weight,
The coating composition according to claim 3, which contains 2 to 50% of a water-soluble resin.