JP2001049151A - Production of polymeric emulsifier and production of emulsion using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing in high polymerization stability an emulsion excellent in storage stability and capable of giving coating films with high weatherability, and to obtain a polymeric emulsifier to be used in producing such an emulsion. SOLUTION: This polymeric emulsifier consists of an aqueous polymer having piperidine skeleton-contg. ultraviolet-stable group and an acid value of 0.4-7.0 meq/g with the acidic functional group in the polymer neutralized; more precisely, the aqueous polymer is composed of (A) 5-50 wt.% of piperidine skeleton- contg. ultraviolet-stable group-contg. monomer unit, (B) 3-60 wt.% of acidic functional group-contg. monomer unit, (C) 20-92 wt.% of hydrophobic monomer unit other than the unit A, and as necessary, furthermore <=50 wt.% of other monomer unit. The other objective emulsion is obtained by emulsion polymerization of a radical-polymerizable monomer in the presence of the above polymeric emulsifier.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing an emulsion having excellent polymerization stability and an emulsion capable of forming a film having excellent storage stability and excellent weatherability, and a method for producing the emulsion. It relates to a molecular emulsifier.

[0002]

2. Description of the Related Art An emulsion polymer having a monomer unit having a UV-stable group containing a piperidine skeleton as a constitutional unit is conventionally known as an emulsion for providing a film having excellent weather resistance (Japanese Patent No. 2637574). ). Further, as a coating composition for providing a coating having excellent weather resistance, an aqueous coating composition comprising a mixture of an aqueous dispersion and an emulsion having a monomer unit having a UV-stable group containing a piperidine skeleton as a constituent unit has been proposed. (Japanese Patent Laid-Open No. 7-31)
0041).

Furthermore, a monomer having an ultraviolet-stable group containing a piperidine skeleton obtained by emulsion-polymerizing a radical-polymerizable monomer in the presence of a polymer emulsifier comprising a polymer obtained by radical polymerization. A polymer having a unit as a constituent unit is known (JP-A-5-140240).

[0004]

However, Patent No. 26
The emulsion polymer disclosed in Japanese Patent No. 37574 and the coating composition described in Japanese Patent Application Laid-Open No. 7-310041 may have insufficient weather resistance under severe conditions of use and the like. Was restricted. Also, Japanese Unexamined Patent Publication No.
The polymer disclosed in JP-A-140240 may have insufficient stability, and depending on the conditions, the viscosity of the polymer dispersion during or after production may increase or the polymer may be gelled. Was limited. In addition, the polymer may have insufficient weather resistance depending on the use conditions.

The present invention has been made by focusing on the problems existing in the prior art as described above. The objective is to provide a method for producing an emulsion that has excellent storage stability and an emulsion capable of forming a film having excellent weather resistance, and a polymer emulsifier used for producing the emulsion. To provide.

[0006]

In order to achieve the above object, the polymer emulsifier according to the first aspect of the present invention has an ultraviolet light-stable group containing a piperidine skeleton and has an acid value of 0.4 to 0.4.
It is 7.0 meq / g and is made of an aqueous polymer in which acidic functional groups in the polymer are neutralized.

The polymer emulsifier according to claim 2 is characterized in that, in the invention according to claim 1, the aqueous polymer has an ultraviolet-stable group-containing monomer unit (A) 5 containing a piperidine skeleton.
50% by weight, acidic functional group-containing monomer unit (B) 3 to 60
% By weight and a hydrophobic monomer unit (C) 2 other than the above (A)
It is a neutralized polymer having a composition of 0 to 92% by weight.

The polymer emulsifier according to claim 3 is the polymer according to claim 2, wherein the polymer further contains 50% by weight of a monomer unit other than (A), (B) and (C).
The following are included.

According to a fourth aspect of the present invention, there is provided a method for producing an emulsion, wherein an emulsion polymerization of a radically polymerizable monomer is carried out in the presence of the high molecular emulsifier according to any one of the first to third aspects. It is.

[0010]

Embodiments of the present invention will be described below in detail. In the present specification, “acryl or methacryl” is referred to as (meth) acryl, “acrylate or methacrylate” is referred to as (meth) acrylate, and “acryloyl or methacryloyl” is referred to as (meth) acryloyl.

The polymer emulsifier has a UV-stable group containing a piperidine skeleton, and has an acid value of 0.4 to 7.0 meq / g.
And an aqueous polymer in which acidic functional groups in the polymer are neutralized. Acid value is 0.4 meq / g
In any case of less than 7.0 meq / g or less, the polymer emulsifier becomes insufficient in emulsifying power and 7.0 meq / g.
/ G, the coating formed from the emulsion described later has low water resistance.

The polymer is composed of 5 to 50% by weight of a monomer unit (A) having a UV-stable group containing a piperidine skeleton, 3 to 60% by weight of a monomer unit (B) having an acidic functional group, and (A) 20) to 92% by weight of a hydrophobic monomer unit (C) other than the above) and 50% by weight of another monomer unit if necessary.
It is desirable to have the following configuration.

The UV-stable monomer forming the UV-stable group-containing monomer unit (A) is a monomer having a piperidine skeleton and at least one polymerizable unsaturated group in the molecule. Is a hindered amine monomer having a polymerizable unsaturated bond represented by the following structural formula (1).

[0014]

Embedded image However, R ₁ is a hydrogen atom or a cyano group, R ₂ and R ₃ are each independently a hydrogen atom, a methyl group or an ethyl group, X is an imino group or an oxygen atom, Y is a hydrogen atom, and has 1 to 18 carbon atoms.
Or an alkyl group of —COCR ₂ ＣＲCR ₃ H (provided that R ₂
And R ₃ represent the same meaning as described above.
2,6,6-pentamethyl-4-piperidyl (meth) acrylate, 2,2,6,6-tetramethylpiperidyl (meth) acrylate, 4- (meth) acryloylamino-2,2,6,6-tetramethyl Piperidine, 4-
(Meth) acryloylamino-1,2,2,6,6-pentamethyl-4-piperidine, 4-cyano-4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 4-cyano- 4- (meth) acryloylamino-1,2,2,6,6-pentamethyl-4-piperidine, 4-crotonoylamino-2,2,6,6-tetramethylpiperidine, 4-crotonoylamino-1,
2,2,6,6-pentamethyl-4-piperidine and the like can be mentioned.

The content of the UV-stable monomer unit (A) is preferably in the range of 5 to 50% by weight. When the content is less than 5% by weight, a film formed from an emulsion described below obtained using a polymer emulsifier may have insufficient weather resistance. May be low, or may be prone to yellowing.

Next, examples of the acidic functional group-containing monomer that forms the acidic functional group-containing monomer unit (B) include a carboxyl group-containing monomer and a sulfonic acid group-containing monomer. Specifically, α, such as methacrylic acid, acrylic acid, maleic acid, maleic anhydride, itaconic acid, crotonic acid, etc.
β-monoethylenically unsaturated carboxylic acid, 2-acryloylamide-2-methylpropanesulfonic acid, styrenesulfonic acid and the like can be mentioned.

The content of the acidic functional group-containing monomer unit (B) is preferably in the range of 3 to 60% by weight. In any case where the content is less than 3% by weight or more than 60% by weight, the polymer emulsifier tends to have insufficient emulsifying power, and if it exceeds 60% by weight, a film formed from an emulsion described later has poor water resistance. It is easy to be low.

Next, the ultraviolet-stable monomer unit (A)
As the hydrophobic monomer forming the hydrophobic monomer unit (C) other than the above, a monomer having a solubility in 100 g of water of 2 g or less is preferable. Specific examples of such a monomer include methyl methacrylate, ethyl (meth) acrylate,
Isopropyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, (meth) acryl Alkyl (meth) acrylates such as 2-ethylhexyl acid, n-octyl (meth) acrylate, isooctyl (meth) acrylate, n-nonyl (meth) acrylate and isononyl (meth) acrylate, styrene, α-methyl Vinyl aromatic monomers such as styrene and vinyl toluene, and olefin monomers such as propylene, butylene, isobutylene, and pentene are used. Among these, n-butyl acrylate, 2-ethylhexyl acrylate,
Cyclohexyl (meth) acrylate and styrene are preferred.

The content of the hydrophobic monomer unit (C) is from 20 to
Desirably, it is 92% by weight. When the content is less than 20% by weight, the polymer emulsifier may have insufficient emulsifying power, and when the content exceeds 92% by weight, the monomer unit (A) having an ultraviolet light-stable group or the acid functional group-containing one. Since the content ratio of the monomer unit (B) is low, the film formed from the emulsion described later has insufficient weather resistance or the polymer emulsifier has insufficient emulsifying power. There are cases.

The other monomer units are units other than the above-mentioned UV-stable monomer unit (A), monomer unit containing acidic functional group (B) and hydrophobic monomer unit (C). Examples of the monomer forming the other monomer unit include, for example, basic unsaturated monomers other than those described above, polyfunctional (meth) acrylic esters, (meth) acrylamides, and unsaturated monomers containing an organic silicon group. For example, a monomer, an allyl (meth) acrylate, glycidyl methacrylate, an oxazoline group-containing monomer, an aziridine group-containing monomer, or the like is used.

Examples of the basic unsaturated monomer include dimethylaminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylamide, vinylpyridine, and vinylpyrrolidone. As the polyfunctional (meth) acrylates, esters of (meth) acrylic acid with polyhydric alcohols such as ethylene glycol, 1,3-butylene glycol, diethylene glycol, polyethylene glycol, and trimethylolpropane are used. As (meth) acrylamides, N-methylol (meth) acrylamide, N-butoxymethyl (meth) acrylamide and the like are used. Organic silicon group-containing unsaturated monomers include vinyltrimethoxysilane, γ- (meth)
Acryloxypropyltrimethoxysilane, allyltriethoxysilane and the like are used.

By using other monomers, the strength of the film formed by the emulsion obtained by using the polymer emulsifier can be improved, or a specific effect corresponding to the type of the monomer used can be obtained. Can be demonstrated.

The content of other monomer units is 50% by weight.
The following is preferred. The reason is that if this content exceeds 50% by weight, the above (A), (B) or (C)
This is because the content of each monomer unit becomes small, and it may be difficult to form an emulsion having excellent stability or a coating having excellent weather resistance.

Next, a polymer emulsifier is obtained by neutralizing the acidic functional group in the polymer obtained by subjecting each of the above monomers to radical polymerization. As the polymerization method, in addition to the solution polymerization method, a bulk polymerization method, an emulsion polymerization method, and the like are appropriately adopted. Known solvents can be used as the solvent in the case of performing the solution polymerization, but a solvent that dissolves the produced polymer emulsifier is preferable. Known radical polymerization initiators can be used. In radical polymerization, a chain transfer agent is used as needed.
Examples of the chain transfer agent include mercaptopropionic acid, mercaptoethanol, alkyl mercaptan, and alkyl thioglycolate.

The weight average molecular weight (Mw) of the polymer is preferably from 1,000 to 100,000. The reason is that when the weight average molecular weight is less than 1,000, a film formed from an emulsion described below may have low water resistance, durability, weather resistance, solvent resistance, and the like,
If it exceeds 100,000, it may be difficult to produce an emulsion.

The polymer emulsifier may be a reaction product of a radical polymer and a compound having a UV-stable group containing a piperidine skeleton other than those obtained by the above method. Examples of the radical polymer include a polymer having a carboxyl group or an acid anhydride group. Examples of the compound having an ultraviolet light stable group include a compound having an ultraviolet light stable group and a hydroxyl group or a compound having an ultraviolet light stable group and a primary or secondary compound.
And a compound having a secondary amino group. By reacting a carboxyl group or an acid anhydride group in the above polymer with a hydroxyl group or a primary or secondary amino group in the ultraviolet light-stable compound, a desired polymer emulsifier can be obtained. These reactions can be performed simultaneously with the production of the radical polymer. For example, a compound having a UV-stable group and a hydroxyl group,
A method in which a radical polymerizable monomer having a carboxyl group, other radical polymerizable monomers, and the like are charged into a reactor and reacted.

Next, a method for producing an emulsion using the above polymer emulsifier will be described. The emulsion is obtained by performing emulsion polymerization of a radically polymerizable monomer in the presence of the above-described polymer emulsifier. The radical polymerizable monomer is not particularly limited, but specific examples thereof include:
Methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl acrylate, cycloalkyl (meth) acrylate, hydroxyethyl (meth) acrylate, (meth)
Acrylic acid, glycidyl methacrylate, oxazoline group-containing monomer, aziridine group-containing monomer, alkoxysilyl group-containing monomer, N-methylolacrylamide, polyfunctional (meth) acrylate, divinylbenzene, styrene, vinyl acetate, etc. Can be The amount of the polymer emulsifier to be used is preferably 5 to 50 parts by weight based on 100 parts by weight of the polymerizable component other than the polymerizable emulsifier, ie, the radical polymerizable monomer component used for emulsion polymerization.

The emulsion obtained as described above is blended with 1 to 30% by weight of a polyfunctional compound (crosslinking agent) having a reactivity with an acidic functional group in the polymer emulsifier to prepare a curable composition. It may be prepared. As such a polyfunctional compound, an epoxy compound, an oxazoline compound, an aziridine compound, a carbodiimide, a methylol compound, or the like is used. The emulsion or curable composition is useful as a coating composition.

Other emulsions may optionally contain fillers such as calcium carbonate and titanium oxide, ultraviolet absorbers such as benzophenone compounds, ultraviolet stabilizers such as hindered amine compounds, antioxidants such as hindered phenol compounds, dioctyl phthalate. , A colorant, an organic solvent, and the like.

[0030]

The film formed from the obtained emulsion is
Excellent weather resistance can be exhibited. Although the reason cannot be determined, since the monomer unit (A) having a UV-stable group containing a piperidine skeleton is present at a high concentration in the hydrophilic portion of the emulsion, the degradation resistance in the hydrophilic portion which is susceptible to degradation is present. It is estimated that performance is improved.

On the other hand, in a conventional emulsion polymer having a monomer unit having a UV-stable group as a constitutional unit, the UV-stable monomer unit is present in a hydrophobic portion at a high concentration. It is considered that the deterioration of the steel cannot be completely prevented. Further, a film formed from a composition consisting of a mere mixture of an aqueous dispersion and an emulsion having a UV-stable group-containing monomer unit as a constituent unit, an emulsifier having no UV-stable group near the surface of the emulsion particles. Since the concentration is high, the emulsion particles are considered to be easily deteriorated by ultraviolet rays.

[0032]

EXAMPLES Hereinafter, reference examples, examples and comparative examples will be given.
The embodiment will be described more specifically. In each example, parts represent parts by weight. The meanings of the abbreviations in the table are as follows.

MMA: methyl methacrylate BA: butyl acrylate IBA: isobutyl acrylate CHMA: cyclohexyl methacrylate MAA: methacrylic acid HA: 2-ethylhexyl acrylate GMA: glycidyl methacrylate Revenol WZ: manufactured by Kao Corporation, sodium polyoxyethylene alkyl phenyl ether sulfate (Reference Example 1, Production of Polymer Emulsifier A) Isopropyl alcohol 7 was placed in a flask equipped with a stirrer, a cooling pipe and a thermometer.
Three parts were charged, and the inside temperature was set to 81 ° C. while setting in a water bath and blowing nitrogen. Next, 29 parts of methyl methacrylate, 50 parts of isobutyl acrylate, 11 parts of methacrylic acid, and ADK STAB LA-82 [trade name of Asahi Denka Kogyo Co., Ltd., 1,2,2,6,6-pentamethyl-4-piperidyl methacrylate] Azobisisobutyronitrile (AIBN) was used as a polymerization initiator in 10 parts.
20% of the monomer mixture in which 1 part was dissolved was charged to the flask. When the internal temperature returns to 81 ° C, AIBN0.
After charging 1 part, 80% of the monomer mixture was heated to an internal temperature of 81 ° C.
Over 4 hours to carry out polymerization.

After dropping, 0.3 parts of AIBN was charged,
Aged at an internal temperature of 81 ° C for 3 hours, acid value 1.28 meq /
g, piperidine concentration: 0.417 meq / g, weight average molecular weight: 5,804 [calculated as polystyrene by gel permeation chromatography (GPC)], glass transition temperature: 54
C. (measured value by differential scanning calorimetry (DSC)). The isopropyl alcohol was distilled off from the solution of the polymer A under heating and reduced pressure while appropriately adding aqueous ammonia, and then adjusted to pH 8 and a nonvolatile content of 20% using aqueous ammonia to obtain an aqueous solution of the polymer emulsifier A. Alternatively, an aqueous dispersion (hereinafter, referred to as an aqueous liquid) was obtained. In each example,
The non-volatile content means the ratio of components remaining after the sample is heated at 155 ° C. for 30 minutes to remove volatile components. The reaction temperature was controlled within a range of ± 1 ° C. (Reference Example 2, Production of Polymer Emulsifier B) As shown in Table 1, isopropyl alcohol was replaced with methyl ethyl ketone.
The same operation as in Reference Example 1 was carried out except that the amount of AIBN dissolved in the monomer mixture was changed to 0.5 part and the polymerization temperature was changed to 78 ° C, the acid value was 1.28 meq / g, and the piperidine group equivalent was 0.417 meq / g, weight average molecular weight 10,10
8. Polymer B having a glass transition temperature of 57 ° C. was obtained. further,
By the same operation as in Reference Example 1, the pH was 8 and the nonvolatile content was 20%.
The aqueous liquid of the polymer emulsifier B adjusted to the above was obtained. (Reference Example 3, Production of Polymer Emulsifier C) The same operation as in Reference Example 1 was carried out except that the monomer composition shown in Table 1 was changed.
Acid value 2.41 meq / g, piperidine group equivalent 0.417
Polymer C having a meq / g, a weight average molecular weight of 8,817 and a glass transition temperature of 50 ° C. was obtained. Further, by the same operation as in Reference Example 1, an aqueous liquid of the polymer emulsifier C adjusted to pH 8 and a nonvolatile content of 20% was obtained. (Reference Example 4, Production of Polymer Emulsifier D) The reference example was repeated except that the monomer composition was changed to that shown in Table 1 and that 2.0 parts of mercaptopropionic acid as a chain transfer agent was used for adjusting the molecular weight. Perform the same operation as in Example 1 to obtain an acid value of 4.47 meq.
/ G, weight average molecular weight 7663, glass transition temperature 46 ° C
Of Polymer D was obtained. Further, by the same operation as in Reference Example 1, an aqueous liquid of the polymer emulsifier D adjusted to pH 8 and a nonvolatile content of 20% was obtained. (Reference Example 5, Production of Polymer Emulsifier E) Except for changing the monomer composition shown in Table 1, the same operation as in Reference Example 4 was performed.
Polymer E having an acid value of 2.63 meq / g, a weight average molecular weight of 7463, and a glass transition temperature of 53 ° C was obtained. Further, by the same operation as in Reference Example 1, an aqueous liquid of the polymer emulsifier E adjusted to pH 8 and a nonvolatile content of 20% was obtained.

[0035]

[Table 1] (Example 1) Into a flask equipped with a stirrer, a condenser and a thermometer, 45 parts of ion-exchanged water and 125 parts of an aqueous liquid of the polymer emulsifier A (solid content 20%, pH 8) were charged and set in a water bath. The internal temperature was 82 while blowing nitrogen.
° C. After the internal temperature was stabilized at 82 ° C., 0.35 part of ammonium persulfate was dissolved in 2.5 parts of ion-exchanged water and 0.05 part of 25% aqueous ammonia and charged into the flask.
Five minutes later, 68 parts of methyl methacrylate and 2-
A monomer prepared by adding 35 parts of ion-exchanged water and 0.1 part of Emal 2F (trade name of Kao Corporation, 30% aqueous solution of sodium lauryl sulfate) to a monomer composition comprising 32 parts of ethylhexyl acrylate. 3 body emulsions
The solution was dropped uniformly while maintaining the internal temperature at 82 ° C. over time.

After completion of the dropwise addition, the internal temperature was maintained at 82 ° C. for 30 minutes, the internal temperature was lowered to 65 ° C., and 0.06 part of t-butyl hydroperoxide was diluted with 0.7 part of ion-exchanged water and added. 5 minutes later, Rongalit 0.06
A part thereof dissolved in 0.1 part of ion-exchanged water was added.
Thereafter, the internal temperature was maintained at 65 ° C. for 30 minutes, and then diluted and
The polymer dispersion (1) was obtained by filtration through a 00 mesh poly net. The polymerization stability was good. In addition, the filterability was good, and only a small amount of aggregate was filtered off from the polynet. The resulting aqueous polymer dispersion (1) had a nonvolatile content of 39.2%, a pH of 8.0, a viscosity of 30 cps, and a particle size of 356.
nm (measured by a laser light diffraction scattering particle size distribution analyzer). In addition, the glass transition temperature (DSC measured value) of the resin of (1) was 49 ° C. (Example 2) Polymer dispersion liquid (1) obtained in Example 1
Then, Epocross WS-500 (trade name, manufactured by Nippon Shokubai Co., Ltd., oxazoline-based cross-linking agent, nonvolatile content: 40%) was used in a ratio of 5 parts by nonvolatile content to 100 parts of nonvolatile content of polymer dispersion liquid (1). It was blended uniformly. No agglomerates were formed by the blending. Example 3 A polymer dispersion (2) was obtained in the same manner as in Example 1 except that the monomer composition was changed as shown in Table 2. The filterability was good and there was almost no aggregate. The resulting polymer dispersion (2) had a nonvolatile content of 40.0%.
%, PH 7.7, viscosity 80 cps, and particle diameter 87 nm. The glass transition temperature of the resin component of the polymer dispersion liquid (2) was 49 ° C. (Example 4) A polymer dispersion (3) was prepared in the same manner as in Example 1 except that the emulsifier was changed as shown in Table 2.
I got The filterability was good and there was almost no aggregate.
The resulting polymer dispersion (3) has a nonvolatile content of 39.5%,
H7.1, viscosity 30 cps, particle diameter 80 nm. Further, the glass transition temperature of the resin component of the polymer dispersion liquid (3) is 4
8 ° C. (Example 5) Polymer dispersion liquid (3) obtained in Example 4
Then, Epocloth WS-500 used in Example 2 was uniformly blended with the active ingredient at a ratio of 5 parts with respect to 100 parts of the solid content of the polymer dispersion (3). No agglomerates were formed by the blending. (Example 6) The polymer dispersion liquid (3) obtained in Example 4
Then, Denacol EX-313 (trade name, epoxy type crosslinking agent, 100% active ingredient, manufactured by Nagase Kasei Kogyo Co., Ltd.) was used in an amount of 5 parts by weight of the active ingredient with respect to 100 parts of the solid content of the polymer dispersion (3). It was blended uniformly in the ratio. No agglomerates were formed by the blending. (Example 7) A polymer dispersion (4) was obtained in the same manner as in Example 1, except that the emulsifier and the monomer composition were changed as shown in Table 2. The filterability was good and there was almost no aggregate. The resulting polymer dispersion (4) had a nonvolatile content of 39.7%, a pH of 7.3, a viscosity of 30 cps and a particle diameter of 80 n.
m. The glass transition temperature of the resin component of the polymer dispersion liquid (4) was 48 ° C. (Example 8) A polymer dispersion (5) was obtained in the same manner as in Example 1, except that the emulsifier and the monomer composition were changed as shown in Table 2. The filterability was good and there was almost no aggregate. The resulting polymer dispersion (5) had a nonvolatile content of 40.3%, a pH of 7.5, a viscosity of 20 cps, and a particle diameter of 83 n.
m. The glass transition temperature of the resin component of the polymer dispersion liquid (5) was 50 ° C. (Comparative Example 1) 68 parts of ion-exchanged water and 0.68 part of Emal 2F used in Example 1 were charged into a flask equipped with a stirrer, a cooling pipe and a thermometer, and set in a water bath while blowing nitrogen thereinto. The temperature was 82 ° C. After the internal temperature was stabilized at 82 ° C., 0.35 part of ammonium persulfate was dissolved in 2.5 parts of ion-exchanged water and 0.5 part of 25% aqueous ammonia and charged into the flask. After 5 minutes, a monomer composition comprising 67 parts of methyl methacrylate, 32 parts of 2-ethylhexyl acrylate and 1 part of methacrylic acid was added to 40 parts of ion-exchanged water and 0.6% of Emal 2F 0.6.
The monomer emulsion prepared by adding 8 parts was dropped uniformly over 3 hours while maintaining the internal temperature at 82 ° C.

After dropping, the internal temperature was maintained at 82 ° C. for 30 minutes, then the internal temperature was lowered to 65 ° C., and 0.06 part of t-butyl hydroperoxide was diluted with 0.7 part of ion-exchanged water and added. 5 minutes later, Rongalit 0.06
A part thereof dissolved in 0.1 part of ion-exchanged water was added.
Thereafter, the internal temperature was maintained at 65 ° C. for 30 minutes, and then diluted and
The mixture was filtered through a 00 mesh poly net to obtain a polymer dispersion liquid (6). The filterability was good and there was almost no aggregate. The resulting aqueous polymer dispersion (6) had a nonvolatile content of 45.1.
%, PH 8.3, viscosity 50 cps, particle size 88 nm. The glass transition temperature of the resin component of the aqueous polymer dispersion (6) was 50 ° C. Comparative Example 2 The same operation as in Comparative Example 1 was carried out except that the emulsifier and the monomer composition were changed as shown in Table 3, to obtain a polymer aqueous dispersion (7). The filterability was poor, and a large amount of aggregate was formed. The resulting polymer dispersion (7) had a nonvolatile content of 44.3%, a pH of 8.3, a viscosity of 20 cps, and a particle size of 8
6 nm. The glass transition temperature of the nonvolatile content of the polymer dispersion (7) was 46 ° C. (Comparative Example 3) The emulsifier and the monomer composition are the same as those of Comparative Example 2, but the LA-82 of the monomer component is separately stored without being initially added to the monomer emulsion, and the monomer amount is reduced in 2 hours. When half of the solid emulsion was dropped, the whole amount of LA-82 was quickly mixed with the remaining monomer emulsion, and then the emulsion was dropped over 2 hours. Otherwise, the same operation as in Comparative Example 2 was performed to obtain an aqueous polymer dispersion (8). The filterability was good, and almost no aggregate was formed. The resulting polymer dispersion (8) had a nonvolatile content of 45.4% and a pH of 8.0.
4. The viscosity was 20 cps and the particle diameter was 86 nm. The glass transition temperature of the nonvolatile component of the polymer dispersion liquid (8) is 47 ° C.
Met. (Comparative Example 4) The same operation as in Example 1 was carried out except that the emulsifier and the monomer composition were changed as shown in Table 3, and an attempt was made to synthesize a polymer aqueous dispersion (9). A large amount of aggregates are generated inside, and the amount of adhesion to the flask wall and thermometer is large,
Further, the liquid contained many agglomerates, clogged the polynet, and could not be filtered. Thus, the polymerization stability was extremely poor, and the subsequent evaluation was not performed. (Comparative Example 5) An aqueous polymer dispersion (10) was obtained in the same manner as in Example 1, except that the emulsifier and the monomer composition were changed as shown in Table 3. The filterability was good and there was almost no aggregate. The obtained polymer dispersion (10) had a nonvolatile content of 40.1%, a pH of 7.2, a viscosity of 35 cps and a particle diameter of 79 nm. The glass transition temperature of the nonvolatile content of the polymer dispersion liquid (10) was 49 ° C. (Comparative Example 6) Aqueous dispersion of polymer obtained in Comparative Example 1 (6)
A polymer emulsifier A (Reference Example 1, nonvolatile content 20%, pH
8) was uniformly blended at a ratio of 25 parts to 100 parts of the nonvolatile component of the aqueous polymer dispersion (6). No agglomerates were formed by the blending. (Comparative Example 7) Aqueous dispersion of polymer obtained in Comparative Example 1 (6)
A polymer emulsifier B (Reference Example 2, non-volatile content 20%, pH
8) was uniformly blended at a ratio of 25 parts to 100 parts of the nonvolatile component of the aqueous polymer dispersion (6). No agglomerates were formed by the blending. (Evaluation of weather resistance) Using the aqueous polymer dispersions obtained in Examples 1 to 8 and Comparative Examples 1 to 7, white paints having the following compositions were prepared.

Aqueous dispersion of polymer (as nonvolatile content) 100
Parts, 37 parts of ion-exchanged water, 0.3 parts of Emulgen L-40 [trade name of Kao Corporation], BYK-022 (BYK-022)
0.15 parts, BYK-190 (BYK).
5 parts, Proxel BDN (Zeneca) 0.3 part, titanium oxide CR-97 [trade name of Ishihara Sangyo Co., Ltd.] 50
Part, TPBN (manufactured by Dow Chemical Company) 13 parts, SN-13
38 (manufactured by San Nopco) and 1.0 part of RM-8 (manufactured by Rohm and Haas) (204.75 parts in total) The obtained paint was coated on an aluminum plate (JIS H4000.
A5052P Alodine 1000-treated plate) using a bar coater so that the film thickness after drying becomes about 40 μm, dried at 60 ° C. for 30 minutes, and further dried at 120 ° C. for 20 minutes.
A heat treatment was performed for 1 minute to prepare a test coated plate, and the weather resistance was evaluated under the following conditions. (Evaluation of weather resistance) Using a metal weather meter KU-R4 (manufactured by Dainippon Plastics Co., Ltd.), a light source metal halide lamp, light intensity of 80 mW / cm ³ , irradiation time 12
Time (63 ° C./50% RH), pause time 4 hours (63 ° C.
/ 90% RH), 8 hours of dew condensation (30 ° C / 90% R)
H) is repeated as one set, and 24 cycles are performed.
The gloss retention at 60 ° C. after 0 hour was measured.

The results are shown in Tables 2 to 5. In the table, the number of parts of the emulsifier and the post-additional crosslinking agent each represents the amount of nonvolatile components.

[0040]

[Table 2]

[0041]

[Table 3]

[0042]

[Table 4]

[0043]

[Table 5] As shown in Tables 2 to 5, Examples 1 to 8 all had good polymerization stability, and had a 60 ° C gloss retention of 87% or more and were excellent in weather resistance. On the other hand, Comparative Examples 1 to 7
As a result, the polymerization stability was poor, and the gloss retention was 68% or less and the weather resistance was low.

The technical idea grasped from the embodiment will be described below. An emulsion obtained by emulsion polymerization of a radically polymerizable monomer in the presence of the polymer emulsifier according to any one of claims 1 to 3, and an emulsion obtained by emulsion polymerization with an acidic functional group in the polymer emulsifier. 1 to 30% by weight of a reactive polyfunctional compound
A curable composition that is blended.

According to this curable composition, the resulting coating film can have high hardness, particularly good weather resistance, solvent resistance and water resistance. An emulsion obtained by emulsion polymerization of a radical polymerizable monomer in the presence of the polymer emulsifier according to any one of claims 1 to 3, or an emulsion obtained by subjecting the emulsion to an acidic function in the polymer emulsifier. A coating composition comprising 1 to 30% by weight of a polyfunctional compound having reactivity with a group.

According to this coating composition, the obtained coating film can be made to have a particularly good weather resistance, solvent resistance and water resistance and a high hardness, thereby improving the function as a coating. Can be.

[0047]

The present invention has the following effects because it is configured as described above. According to the polymer emulsifier of the first aspect of the present invention, since the acidic functional group in the aqueous polymer is neutralized and ionized, the storage stability is excellent, and the aqueous polymer contains a piperidine skeleton in the aqueous polymer. An emulsion capable of forming a film having excellent weather resistance based on the ultraviolet light stable group can be provided.

According to the polymer emulsifier of the second aspect of the invention, the effects of the first aspect of the invention can be reliably exhibited. According to the polymer emulsifier of the third aspect, in addition to the effect of the first or second aspect, the strength of the coating film is improved in accordance with the type of the other monomer used. And the like.

According to the method for producing an emulsion according to the fourth aspect of the present invention, an emulsion having excellent storage stability and capable of forming a film having excellent weather resistance can be produced with high polymerization stability.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Michihiro Kawai 1 at Funami-cho, Minato-ku, Nagoya-shi, Aichi 1 East Nagoya Co., Ltd. Nagoya Research Institute Co., Ltd. (72) Inventor Tsuguo Kimura Funami, Minato-ku, Nagoya-shi, Aichi No. 1 in the town Toagosei Co., Ltd. Nagoya Research Institute F-term (reference) 4D077 AA03 AB06 AC01 AC05 BA01 BA02 BA05 BA07 CA02 CA15 DC02Z DC39Z DC49Z DD17Y DD18Y DE02Y DE02Z DE16Y DE16Z 4J011 KA15 KA29 KB02 KB08 KB29 4J038 EA142 GA06 GA08 KA09 MA08 MA10 NA03 NA26 4J100 AA03R AA04R AA05R AA06R AA07R AB02R AB03R AB04R AB07Q AJ01Q AJ02Q AJ08Q AJ09Q AK32Q AL03R AL04R AL08P AL08R AL08S AL10S AL62S AL63S AL66S AL75S AM14P AM21P AM21Q AM21S AP16S AQ08S AQ12S BA02S BA03S BA04S BA08S BA31S BA40P BA56Q BA77S BC04R BC65P CA05 CA06 FA20 JA15

Claims (4)

[Claims] An aqueous polymer having an ultraviolet light-stable group containing a piperidine skeleton, an acid value of 0.4 to 7.0 meq / g, and an acidic functional group in the polymer being neutralized. Polymer emulsifier. 2. The aqueous polymer comprises 5 to 50% by weight of a UV-stable group-containing monomer unit having a piperidine skeleton (A), 3 to 60% by weight of an acidic functional group-containing monomer unit (B), and Hydrophobic monomer units other than (A) (C) 20 to 92
2. A neutralized product of a polymer having a weight percent composition.
The polymer emulsifier according to the above. 3. The polymer further comprises (A), (B),
3. The polymer emulsifier according to claim 2, which contains 50% by weight or less of a monomer unit other than (C). 4. A method for producing an emulsion, wherein emulsion polymerization of a radically polymerizable monomer is carried out in the presence of the polymer emulsifier according to any one of claims 1 to 3.