JP2003292507A - Method for producing emulsion polymerization latex - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing an emulsion polymerization latex by which a polymerizable monomer having ≤0.03 mass solubility in water at 20°C is subjected to emulsion polymerization in a high polymerization ratio. <P>SOLUTION: The method for producing the emulsion polymerization latex comprises dispersing a polymerizable monomer containing the polymerizable monomer having ≤0.03 mass solubility in water at 20°C into water by using a line mixer 30 and a homogenizer 40 to give an emulsion having ≤10.0 μm volume average liquid drop diameter and then polymerizing the polymerizable monomer in the emulsion. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an emulsion polymerization in which a polymerizable monomer containing a polymerizable monomer having a solubility in water at 20 ° C. of 0.03% by mass or less is emulsion-polymerized to obtain an emulsion-polymerized latex. The present invention relates to a method for producing latex.

[0002]

2. Description of the Related Art Conventionally, a polymerizable monomer is dispersed in water containing an emulsifier, and the polymerizable monomer is polymerized in a micelle having a layer of a molecule of the emulsifier formed on the surface of the polymer. An emulsion polymerization method for obtaining a polymer latex in which particles are dispersed (hereinafter referred to as emulsion polymerization latex) is known.

For example, a method for producing a polyorganosiloxane by emulsion-polymerizing an organosiloxane is disclosed in JP-A-60-88040 and JP-B-4-710.
97, JP-A-4-261454, JP-A-5
-194740, JP-A-8-259696, JP-A-10-025345, JP-A-11-2
It is disclosed in Japanese Patent No.

[0004]

However, in emulsion polymerization of an organosiloxane, the polymerization proceeds along with a ring-opening reaction and a condensation reaction and is an equilibrium reaction. Therefore, the polymer particles in the emulsion-polymerized latex obtained are obtained. Had a wide particle size distribution, and the polymerization rate of the polymerizable monomer was low. Also, in emulsion polymerization of a polymerizable monomer other than organosiloxane, in the case of a polymerizable monomer having a solubility in water at 20 ° C. of 0.03% by mass or less, the solubility of the polymerizable monomer in water From the low, the polymerization does not proceed because the transfer of the polymerizable monomer from the oil droplets of the polymerizable monomer dispersed in water to the micelle does not easily occur, or not emulsion polymerization in the micelle, but mere There is a problem that the polymerization rate of the polymerizable monomer does not increase because the polymerization proceeds in the oil droplets of the polymerizable monomer.

Therefore, an object of the present invention is to provide a method for producing an emulsion-polymerized latex capable of emulsion-polymerizing a polymerizable monomer having a solubility in water at 20 ° C. of 0.03% by mass or less at a high polymerization rate. To provide.

[0006]

That is, the method for producing an emulsion-polymerized latex of the present invention is a method for producing a polymerizable monomer containing a polymerizable monomer having a solubility in water at 20 ° C. of 0.03% by mass or less. , A line mixer and a homogenizer to disperse in water to obtain a volume average droplet diameter of 10.0.
It is characterized in that the polymerizable monomer in the emulsion is polymerized after obtaining the emulsion having a size of not more than μm.

Further, in the method for producing the emulsion-polymerized latex of the present invention, the homogenizer has a shearing force of 1
It is desirable to use one having a pressure of 0.0 kgf / cm ² or more. In addition, in the method for producing the emulsion-polymerized latex of the present invention, the polymerizable monomer has a solubility in water at 20 ° C. of 0.03% by mass or less, and organosiloxane, 2-ethylhexyl acrylate and It is particularly useful when it contains at least one selected from the group consisting of dodecyl methacrylate.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. FIG. 1 is a schematic configuration diagram showing an example of an apparatus for producing emulsion-polymerized latex. This emulsion-polymerized latex production apparatus comprises an emulsifying apparatus 11 for dispersing a polymerizable monomer containing a polymerizable monomer having a solubility in water at 20 ° C. of 0.03 mass% or less in water, and an emulsifying apparatus 11. The liquid holding tank 12 for temporarily storing the prepared emulsion, the reactor 13 for heating the emulsion to polymerize the polymerizable monomer in the emulsion, and the liquid discharged from the liquid holding tank 12 or the reactor 13. Liquid feed pump 14 for feeding liquid to the emulsifying device 11
And the flow paths 16, 17, 18, 19 and the flow paths 21, 22, 23, 24, 25, 26, 27 for sending the liquid discharged from the emulsifying device 11 to the liquid holding tank 12 or the reactor 13. It is provided with a schematic configuration.

The emulsifying device 11 is a combination of a line mixer 30 for dispersing a polymerizable monomer in water and a homogenizer 40.
The homogenizer 40 and the homogenizer 40 are connected by a flow path 28. The line mixer 30 allows two kinds of liquids, which are not mixed with each other, which are supplied to the pipe having the mixing element arranged therein, to proceed while being rotated by the action of the mixing element, and pass through the pipe while repeating division and merging. By doing so, the mixing / dispersion of these liquids proceeds.

A known mixer can be used as the line mixer 30, and for example, a conduit 3 as shown in FIG.
Within one, the opposite short sides of the rectangular metal plate are relatively
The right winding element 32 twisted to the right by 0 ° and the left winding element 33 twisted by 180 ° to the left on the opposite short side of the rectangular metal plate are arranged so that their short sides are orthogonal to each other. Mixing element 3 consisting of two or more connected alternately
One in which 4 is arranged is included.

The homogenizer 40 is a device for causing two kinds of liquids that are not mixed with each other to flow out from a narrow gap, atomize by shearing due to turbulent flow at that time, and uniformly disperse both liquids. As the homogenizer 40, a known one such as a high pressure homogenizer can be used. The homogenizer 40 has a shearing force of 10.0 k in order to uniformly mix the two kinds of liquids.
It is preferably gf / cm ² or more.

As the liquid-retaining tank 12 and the reactor 13, known tanks equipped with a stirrer, a jacket and the like are used. Further, as the stirring device, a rotary stirring device using a stirring blade such as a propeller blade, a turbine blade, a paddle blade, a three-way swept blade, and a disk blade is generally used.

Next, a method for producing the emulsion-polymerized latex of the present invention will be described with reference to the drawings. First, the liquid holding tank 1
2, water, solubility in water at 20 ℃ 0.03
A predetermined amount of a polymerizable monomer containing a polymerizable monomer of not more than mass% and an emulsifier are charged and stirred.

Then, the mixed liquid in the liquid holding tank 12 is passed through the flow path 1
The liquid is sent to the emulsifying device 11 via 7, 18, and 19 and is passed through the line mixer 30 and the homogenizer 40 in this order in the emulsifying device 11 to emulsify and disperse the polymerizable monomer in water to obtain an emulsion. The emulsion obtained by the emulsifying device 11 is
Liquid is sent to the reactor 13 via the flow paths 23 and 27.

A polymerization catalyst is added to the emulsion fed to the reactor 13, and the emulsion is heated while being stirred in the reactor 13 to polymerize the polymerizable monomer in the emulsion. An emulsion-polymerized latex dispersed in water is obtained.

In the present invention, a polymerizable monomer containing a polymerizable monomer having a solubility in water at 20 ° C. of 0.03% by mass or less is dispersed in water using a line mixer 30 and a homogenizer 40. The feature is that an emulsion having a volume average droplet diameter of 10.0 μm or less is obtained. Volume average droplet diameter of emulsion is 10.0 μm
When it exceeds, the solubility in water at 20 ° C is 0.0
Transfer of the polymerizable monomer from the oil droplets of the polymerizable monomer containing the polymerizable monomer of 3% by mass or less to the micelle hardly occurs, the polymerization does not proceed, or in the emulsion polymerization in the micelle. In some cases, the polymerization may proceed in the case of simple oil droplets of the polymerizable monomer.

Here, the volume average droplet diameter of the emulsion is measured by a laser diffraction / scattering type particle size distribution measuring device (LA-910, manufactured by Horiba, Ltd.).

Solubility in water at 20 ° C. is 0.0
Organosiloxane is mentioned as a polymerizable monomer which is 3 mass% or less. In the present invention, an organosiloxane-based mixture comprising an organosiloxane, a siloxane-based crosslinking agent, and a siloxane-based graft crossing agent,
A method of preparing an organosiloxane latex by adding an emulsifier and water, mixing this with an aqueous acid solution serving as an acid catalyst, and polymerizing the mixture is adopted.

Examples of the organosiloxane include various organosiloxane-based cyclic compounds having 3 or more membered rings, and among them, those having 3 to 6 membered rings are preferable. Specifically, hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane,
Dodecamethylcyclohexasiloxane, trimethyltriphenylcyclotrisiloxane, tetramethyltetraphenylcyclotetrasiloxane, octaphenylcyclotetrasiloxane and the like can be mentioned, and these can be used alone or in admixture of two or more.

As the siloxane-based crosslinking agent, a trifunctional or tetrafunctional silane-based crosslinking agent such as trimethoxymethylsilane, triethoxyphenylsilane, tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, Tetrabutoxysilane or the like is used. Particularly, a tetrafunctional crosslinking agent is preferable, and tetraethoxysilane is particularly preferable. The amount of the crosslinking agent used in the organosiloxane mixture is 0.1 to 30% by mass, preferably 0.5 to 10% by mass.

As the siloxane-based graft crossing agent, compounds capable of forming a unit represented by the following formula are used. ^{_{CH 2 = CR 2 -COO- (CH}} 2) p -SiR 1 n O (3-n) / 2 (I-1) CH 2 = CH-SiR 1 n O (3-n) / 2 (I-2 ) HS- (CH ₂₎ in _{^{p -SiR 1 n O (3-}} n) / 2 (I-3) ( each formula, R ¹ represents a methyl group, an ethyl group, a propyl group or a phenyl group, R ² is hydrogen Atom or methyl group, n is 0, 1 or 2, and p is a number of 1 to 6.)

A unit of formula (I-1) may be formed (meta).
Acryloyloxysiloxane has a high grafting efficiency and therefore can form an effective graft chain, and is advantageous in that it exhibits impact resistance. Methacryloyloxysiloxane is particularly preferable as the unit capable of forming the unit of the formula (I-1). Specific examples of methacryloyloxysiloxane include β-methacryloyloxyethyldimethoxymethylsilane, γ-methacryloyloxypropylmethoxydimethylsilane, γ-methacryloyloxypropyldimethoxymethylsilane, γ-methacryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropyl. Ethoxydiethylsilane, γ-methacryloyloxypropyldiethoxymethylsilane, δ-
Methacryloyloxybutyldiethoxymethylsilane and the like can be mentioned.

Examples of the unit capable of forming the unit of the formula (I-2) include vinyl siloxane, and specific examples thereof include:
Examples include tetramethyltetravinylcyclotetrasiloxane. As the unit capable of forming the unit of the formula (I-3), γ-mercaptopropyldimethoxymethylsilane, γ
-Mercaptopropylmethoxydimethylsilane, γ-mercaptopropyldiethoxymethylsilane and the like can be mentioned. The amount of the graft crossing agent used in the organosiloxane mixture is usually 0.05 to 10% by mass, preferably 0.1 to 5% by mass.

As the emulsifier, a usual anionic emulsifier or nonionic emulsifier is used. The anionic emulsifier is selected from sodium alkylbenzenesulfonate, sodium laurylsulfonate, sodium sulfosuccinate, sodium polyoxyethylenenonylphenyl ether sulfate, potassium alkenylcarboxylate, sodium N-lauroylsarcosine, potassium oleate and the like. Emulsifiers are used. Particularly, sulfonic acid-based emulsifiers such as sodium alkylbenzene sulfonate and sodium lauryl sulfate are preferable.
As the nonionic emulsifier, polyoxyethylene nonylphenyl ether, polyoxyethylene cetyl ether, polyoxyethylene lauryl ether and the like are used.

These emulsifiers are used in the range of 0.05 to 10% by mass based on the organosiloxane mixture. If it is less than 0.05% by mass, the dispersed state becomes unstable, and if it is used in excess of 10% by mass, the coloration of the graft polymer due to the emulsifier becomes undesirably great. The amount of water added to the organosiloxane-based mixture and the emulsifier is not particularly limited, but is usually preferably 10 times or less that of the organosiloxane-based mixed solution. If more water is added than this range, the concentration of the resulting polyorganosiloxane will decrease, making it unsuitable as a raw material for graft polymerization, and also having a large amount of water to be evaporated, making it unsuitable as a raw material for paints. .

As the acid catalyst used in the aqueous acid solution, an acid having no micelle forming ability can be used, and examples thereof include mineral acids such as sulfuric acid, hydrochloric acid and nitric acid. These acid catalysts may be used alone or in combination of two or more. The amount of the acid catalyst used in the acid aqueous solution is in the range of 0.01 to 5 mass% based on the organosiloxane mixture. If the amount of acid catalyst is less than this range, the polymerization rate and the polymerization rate will be small. Further, if the acid catalyst is used in a larger amount than this range, a large amount of alkali is required for neutralization, which is not preferable.

Polymerizable monomers other than organosiloxanes having a solubility in water at 20 ° C. of not more than 0.03% by mass include 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, Stearyl (meth) acrylate,
Examples thereof include cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, 1,6-hexanediol di (meth) acrylate, polybutylene glycol (meth) acrylate, heptadecafluorodecyl (meth) acrylate and the like. These alkyl (meth) acrylates may be used alone or in combination of two or more.

Solubility in water at 20 ° C. is 0.0
As the polymerizable monomer (copolymerization component) other than 3% by mass or less, styrene, p-methylstyrene, o
-Styrene-based monomers such as methylstyrene, p-chlorostyrene, o-chlorostyrene, p-methoxystyrene, o-methoxystyrene, 2,4-dimethylstyrene and α-methylstyrene; methyl (meth) acrylate, ethyl Alkyl (meth) acrylate monomers such as (meth) acrylate and butyl (meth) acrylate; vinyl cyanide monomer such as acrylonitrile and methacrylonitrile; vinyl ether monomers such as vinyl methyl ether and vinyl ethyl ether ; Vinyl carboxylate-based monomers such as vinyl acetate, vinyl butyrate; ethylene, propylene,
Olefin-based monomers such as isobutylene; butadiene,
Examples thereof include diene-based monomers such as isoprene and dimethylbutadiene. These monomers may be added to the 2
The polymerizable monomer having a solubility in water at 0 ° C. of 0.03% by mass or less can be used alone or in combination of two or more.

As the emulsifier and the dispersion stabilizer, any known anionic, nonionic or cationic surfactant can be used. Further, the mixture can be used if necessary, in which case,
It is preferable to use an emulsifier having a large micelle forming ability and a small emulsifier in combination. As the polymerization catalyst, any known polymerization catalyst can be used.

In the method for producing an emulsion-polymerized latex as described above, a liner mixer is used to prepare a polymerizable monomer containing a polymerizable monomer having a solubility in water at 20 ° C. of 0.03% by mass or less. And a homogenizer to disperse it in water to obtain an emulsion having a volume average droplet diameter of 10.0 μm or less, and therefore, a polymerizable monomer having a solubility in water at 20 ° C. of 0.03% by mass or less. Even if there is, the transfer of the polymerizable monomer from the oil droplets of the polymerizable monomer to the micelles easily occurs. Thereby, when the polymerizable monomer in the emulsion is polymerized, emulsion polymerization is facilitated and the polymerization rate of the polymerizable monomer is increased.

Further, in the method for producing the emulsion-polymerized latex of the present invention, the polymerizable monomer has a solubility in water at 20 ° C. of 0.03% by mass or less,
It is particularly useful when it contains at least one selected from the group consisting of organosiloxane, 2-ethylhexyl acrylate and dodecyl methacrylate.

In the method for producing the emulsion-polymerized latex of the present invention, a polymerizable monomer containing a polymerizable monomer having a solubility in water at 20 ° C. of not more than 0.03% by mass is passed through a line mixer and a homogenizer. It may be used by dispersing in water to obtain an emulsion having a volume average droplet diameter of 10.0 μm or less, and then polymerizing the polymerizable monomer in the emulsion. A method may be used in which a polymerizable monomer, an emulsifier, water and the like are charged, the mixture is emulsified and dispersed by the line mixer 30 and the homogenizer 40 to form an emulsion, and the emulsion is fed to the reactor 13 and then polymerized. .

The apparatus for producing emulsion-polymerized latex also comprises
The method using the manufacturing apparatus of the illustrated example is not limited, and, for example, as shown in FIG. 3, a mixing tank 15 for charging a polymerizable monomer, an emulsifier, water, etc. to obtain a mixed solution and a channel 29 are used. The emulsifying device 11 including a combination of the line mixer 30 and the homogenizer 40 connected to each other, the reactor 13 for polymerizing the polymerizable monomer in the emulsion, and the mixed liquid discharged from the mixing tank 15 are sent to the emulsifying device 11. The apparatus may be provided with a liquid sending pump 50 and a flow path 51 for liquid, and a flow path 52 for sending the emulsion discharged from the emulsifying device 11 to the reactor 13.

To obtain an emulsion, the mixed liquid may be first emulsified and dispersed by the line mixer 30 and then further homogenized and dispersed by the homogenizer 40. First, the mixed liquid may be emulsified and dispersed by the homogenizer 40 and then the line mixer. It may be further emulsified and dispersed at 30. However, from the viewpoint of the dispersion capacity of the apparatus, a method is preferred in which the mixed solution is first emulsified and dispersed by the line mixer 30 to obtain a stable dispersion, and then further homogenized and dispersed by the homogenizer 40.

As for the method of polymerizing the polymerizable monomer in the reactor 13, in addition to the method of collectively polymerizing the emulsion forcibly emulsified in the emulsifying device 11, a part of the emulsion is preliminarily polymerized A method of dropping the remaining emulsion and polymerizing the same can be mentioned.

[0036]

The present invention will be further described with reference to the following examples, but the present invention is not limited to these examples. Further, in the present examples, “parts” and “%” mean “parts by mass” and “mass%” unless otherwise specified.

[Volume Average Droplet Size of Emulsion] The particle size of the emulsion was measured by using a laser diffraction / scattering particle size distribution analyzer (LA-910, manufactured by Horiba, Ltd.) with a sample prepared by diluting the emulsion with distilled water. It was measured.

[Particle size of polymer in latex] The particle size of the polymer in latex was obtained by diluting the obtained latex with distilled water.
It was measured using a CHDF2000 type particle size distribution meter manufactured by ATEC. The measurement conditions were standard conditions recommended by MATEC. Using a dedicated capillary cartridge for particle separation and a carrier liquid, the liquid is almost neutral, the flow rate is 1.4 ml / min, the pressure is about 4000 psi, and the temperature is kept at 35 ° C. 0.1 ml of diluted latex sample was used for the measurement. As the standard particle size substance, monodisperse polystyrene having a known particle size manufactured by DUKE, Inc. in the United States was used in the range of 0.02 μm to 0.8 μm for a total of 12
Used points.

[Embodiment 1] Octamethylcyclotetrasiloxane 10 was placed in a liquid holding tank 12 equipped with a stirrer as shown in FIG.
Charge 0.0 part, 2 parts of tetraethoxysilane, 0.5 part of γ-methacryloyloxypropyldimethoxymethylsilane, and 150 parts of distilled water in which 1.34 parts of sodium dodecylbenzene sulfonate are dissolved, and mix uniformly by stirring. Made into liquid. This mixed solution was used as a line mixer 30 (manufactured by Tokushu Kika Kogyo Co., Ltd., model name: 2S) and a homogenizer 40 (high pressure homogenizer manufactured by GAULIN, model name: D2400, flow rate 3000 liter / hr, 20).
0 kgf / cm ² ) was emulsified and dispersed to obtain an emulsion, and the emulsion was stored in the reactor 13 equipped with a stirrer. The volume average droplet diameter of the emulsion was 0.40 μm.

With the emulsion heated to 80 ° C.,
A 0.40% sulfuric acid aqueous solution in which 0.20 parts of sulfuric acid and 50 parts of distilled water were mixed was added thereto, and the temperature was maintained for 7 hours and then cooled. Next, this reaction product was kept at room temperature for 12 hours and then neutralized with a 10% aqueous sodium hydroxide solution. The emulsion-polymerized latex obtained in this way is heated at 180 ° C.
The solid content was determined by drying for 30 minutes at 29.8%
Met. In addition, as a result of measuring the particle diameter, 351 nm
Had a peak at.

Example 2 Octamethylcyclotetrasiloxane 10 was placed in a reactor 13 equipped with a stirrer as shown in FIG.
0.0 parts, 2.0 parts of γ-methacryloyloxypropyldimethoxymethylsilane, and 310 parts of distilled water in which 0.67 parts of sodium dodecylbenzenesulfonate were dissolved were charged, and a uniform mixed solution was obtained by stirring. This mixed solution was used as a line mixer 30 (manufactured by Tokushu Kika Kogyo Co., Ltd., model name: 2S) and a homogenizer 40 (GAULIN
High pressure homogenizer manufactured by the company, model name: D2400, flow rate 3
It was emulsified and dispersed using 000 liter / hr and 200 kgf / cm ² ) to obtain an emulsion, and the emulsion was stored in a liquid holding tank 12 equipped with a stirrer. The volume average droplet diameter of the emulsion was 0.65 μm.

10.0 parts of dodecylbenzene sulfonic acid and 90 parts of distilled water were charged into the reactor 13, and the emulsion in the liquid holding tank 12 was dropped into the reactor 13 over 4 hours while the temperature was raised to 85 ° C. . The temperature was maintained for 1 hour and cooled. The reaction was then kept at room temperature for 12 hours,
It was neutralized with a 10% aqueous sodium hydroxide solution. The emulsion-polymerized latex thus obtained was dried at 180 ° C. for 30 minutes to determine the solid content, which was 18.5%. Also,
As a result of particle size measurement, it had a peak at 60 nm.

Comparative Example 1 An emulsion polymerized latex was obtained in the same manner as in Example 1 except that the line mixer 30 was not used during the first emulsion dispersion and only the homogenizer 40 was used. The volume average droplet diameter of the emulsion before polymerization is 0.6.
It was 0 μm. When the solid content of the obtained latex was determined, it was 26.3%. Further, as a result of measuring the particle size, it had a peak at 320 nm.

Comparative Example 2 Except that only the homogenizer 40 was used without using the line mixer 30 during emulsion dispersion.
An emulsion-polymerized latex was obtained in the same manner as in Example 2. The volume average droplet diameter of the emulsion before polymerization was 0.75 μm. When the solid content of the obtained latex was determined,
It was 16.9%. In addition, as a result of measuring the particle size,
It had a peak at 100 nm.

Comparative Example 3 An emulsion-polymerized latex was obtained in the same manner as in Example 1 except that the homogenizer 40 was not used during the first emulsion dispersion and only the line mixer 30 was used. The volume average droplet diameter of the emulsion before polymerization is 1.5.
It was 0 μm. When the solid content of the obtained latex was determined, it was 25.0%. Further, as a result of measuring the particle size, it had a peak at 163 nm.

(Comparative Example 4) Except that only the line mixer 30 was used without using the homogenizer 40 during emulsion dispersion.
An emulsion-polymerized latex was obtained in the same manner as in Example 2. The volume average droplet diameter of the emulsion before polymerization was 1.95 μm. When the solid content of the obtained latex was determined,
It was 14.3%. In addition, as a result of measuring the particle size,
It had a peak at 90 nm.

The above Examples 1-2 and Comparative Examples 1-4
The results are summarized in Table 1. It can be seen from Table 1 that when the line mixer and the homogenizer are not used as the emulsification / dispersion method, the polymerization rate is lowered and the particle size distribution is widened. In the table, dw is the weight average particle size, and dn
Is the number average particle size, and dw / dn is the particle size distribution.

[0048]

[Table 1]

[Embodiment 3] 2-ethylhexyl acrylate 99.5 was placed in the liquid holding tank 12 with a stirring device shown in FIG.
Parts, allyl methacrylate 0.5 parts, distilled water 195 parts,
Registered trademark Perex S sold by Kao Corporation
S-H (1 part as solid content) was charged, and the mixture was stirred to form a uniform mixed solution. This mixed solution is used as a line mixer 30.
(Manufactured by Tokushu Kika Kogyo Co., Ltd., model name: 2S) and homogenizer 40 (GAULIN high-pressure homogenizer, model name: D2400, flow rate 3000 liter / h)
r, 200 kgf / cm ² ) to obtain an emulsion by emulsification and dispersion, and the emulsion was stored in the reactor 13 equipped with a stirrer. The volume average droplet diameter of the emulsion is 1.60.
was μm.

With the emulsion heated to 50 ° C.,
To this, 0.5 parts of tert-butyl hydroperoxide was added, and further 0.002 parts of ferrous sulfate, 0.006 parts of ethylenediaminetetraacetic acid disodium salt, and 0.26 parts of Rongalit were dissolved in 5 parts of distilled water. The mixed solution was added. Then, it was left for 2 hours to complete the polymerization. The emulsion-polymerized latex obtained in this way was heated at 180 ° C. for 30 days.
When the solid content was obtained by drying for 3 minutes, it was 33.6%. In addition, as a result of particle size measurement, 196 nm and 68
It was a distribution of redispersion having a peak at 0 nm.

Comparative Example 5 An emulsion-polymerized latex was obtained in the same manner as in Example 3 except that the line mixer 30 was not used during the first emulsion dispersion and only the homogenizer 40 was used. The volume average droplet diameter of the emulsion before polymerization is 3.2.
It was 3 μm. When the solid content of the obtained latex was determined, it was 32.9%. Further, as a result of measuring the particle diameter, it had a peak at 190 nm.

[Comparative Example 6] An emulsion polymerized latex was obtained in the same manner as in Example 3 except that the homogenizer 40 was not used during the first emulsion dispersion and only the line mixer 30 was used. The volume average droplet diameter of the emulsion before polymerization is 9.1.
It was 6 μm. The solid content of the obtained latex was 32.8%. In addition, as a result of measuring the particle size, it had a peak at 193 nm.

[Comparative Example 7] 99.5 of 2-ethylhexyl acrylate was added to the reactor 13 equipped with a stirrer shown in FIG.
Parts, allyl methacrylate 0.5 parts, distilled water 195 parts,
Registered trademark Perex S sold by Kao Corporation
S-H (1 part as solid content) was charged, and the mixture was stirred to form a uniform mixed solution. 0.5 parts of tert-butyl hydroperoxide was added while the temperature of this mixed solution was raised to 50 ° C., and further 0.002 parts of ferrous sulfate, 0.006 parts of ethylenediaminetetraacetic acid disodium salt, and Rongalit 0. A mixed solution of 0.26 parts dissolved in 5 parts of distilled water was added.
After 30 minutes of induction, an exothermic heat of polymerization was observed and then left for 2 hours to complete the polymerization. The emulsion-polymerized latex thus obtained was dried at 180 ° C. for 30 minutes to determine the solid content, which was 31.6%. When the cullet at the time of polymerization was dried and weighed, it was 1.8 parts by weight. there were. Further, as a result of measuring the particle diameter, it had a peak at 190 nm.

The results of Example 3 and Comparative Examples 5 to 7 described above are summarized in Table 2. From Table 2, when the line mixer and the homogenizer were not used as the emulsion dispersion method, the particle size distribution was monodisperse. When neither was used, polymerization was delayed and a large amount of cullet was generated.

[0055]

[Table 2]

Example 4 80.0 parts of dodecyl methacrylate, 20 parts of methyl methacrylate, 195 parts of distilled water were added to the liquid holding tank 12 equipped with a stirring device shown in FIG. (1 part as solid content) was charged, and a uniform mixed solution was obtained by stirring. This mixed solution was used as a line mixer 30 (manufactured by Tokushu Kika Kogyo Co., Ltd., model name: 2S) and a homogenizer 40.
(GAULIN high pressure homogenizer, model name: D2
400, flow rate 3000 liters / hr, 200 kgf /
cm ² ) to obtain an emulsion by emulsification and dispersion, and the emulsion was stored in the reactor 13 equipped with a stirrer. The volume average droplet diameter of the emulsion was 0.41 μm.

With the emulsion heated to 50 ° C.,
To this, 0.2 part of isopropylbenzene hydroperoxide was added, and further 0.002 part of ferrous sulfate was added,
0.006 parts of ethylenediaminetetraacetic acid disodium salt,
A mixed solution prepared by dissolving 0.20 parts of L-+-ascorbic acid in 5 parts of distilled water was added. Then, the mixture was left for 2 hours to complete the polymerization. The emulsion-polymerized latex thus obtained was dried at 180 ° C. for 30 minutes to determine the solid content, which was 33.2%. Further, as a result of measuring the particle size, it had a peak at 140 nm.

[Comparative Example 8] An emulsion polymerized latex was obtained in the same manner as in Example 4 except that the line mixer 30 was not used during the first emulsion dispersion and only the homogenizer 40 was used. The volume average droplet diameter of the emulsion before polymerization is 1.2.
It was 7 μm. The solid content of the obtained latex was 32.8%. Further, as a result of measuring the particle diameter, it had a peak at 190 nm.

[Comparative Example 9] An emulsion polymerized latex was obtained in the same manner as in Example 4 except that the homogenizer 40 was not used during the first emulsion dispersion and only the line mixer 30 was used. The volume average droplet diameter of the emulsion before polymerization is 7.1.
It was 6 μm. When the solid content of the obtained latex was determined, it was 32.9%. Further, as a result of measuring the particle size, it had a peak at 230 nm.

[Comparative Example 10] In a reactor 13 equipped with a stirrer shown in FIG. 1, 80.0 parts of dodecyl methacrylate, 20 parts of methyl methacrylate, 195 parts of distilled water, and a registered trademark Perex OTP (trademark of Kao Corporation) were purchased. 1 part) was charged as a solid content, and a uniform mixed solution was obtained by stirring. 0.2 parts of isopropylbenzene hydroperoxide was added in a state where this mixed solution was heated to 50 ° C.,
Further, a mixed solution prepared by dissolving 0.002 part of ferrous sulfate, 0.006 part of ethylenediaminetetraacetic acid disodium salt and 0.20 part of L-+-ascorbic acid in 5 parts of distilled water was added. However, no exothermic heat of polymerization was observed even if left for 1 hour.

The results of Example 4 and Comparative Examples 8 to 10 described above are summarized in Table 3. From Table 3, when the line mixer and the homogenizer were not used as the emulsification / dispersion method, the particle size distribution was shifted to the larger side. When neither was used, the polymerization reaction did not start.

[0062]

[Table 3]

[0063]

As described above, the method for producing an emulsion-polymerized latex according to the present invention uses a polymerizable monomer containing a polymerizable monomer having a solubility in water at 20 ° C. of 0.03% by mass or less. , Volume mixer having a volume average droplet diameter of 10.0 μm
Since the polymerizable monomer in the emulsion is polymerized after obtaining the following emulsion, the polymerizable monomer having a solubility in water at 20 ° C. of 0.03 mass% or less is emulsified at a high polymerization rate. Polymerization is possible and polymer particles can be obtained in high yield.

If a homogenizer having a shearing force of 10.0 kgf / cm ² or more is used, it becomes easy to obtain an emulsion having a volume average droplet diameter of 10.0 μm or less. Such a method for producing an emulsion-polymerized latex, wherein the polymerizable monomer has a solubility in water at 20 ° C. of 0.03% by mass or less,
It is particularly useful when it contains at least one selected from the group consisting of organosiloxane, 2-ethylhexyl acrylate and dodecyl methacrylate.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an example of an apparatus for producing emulsion-polymerized latex.

FIG. 2 is a perspective view showing an example of a line mixer.

FIG. 3 is a schematic configuration diagram showing another example of an apparatus for producing emulsion-polymerized latex.

[Explanation of symbols]

30 line mixer 40 homogenizer

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kimihiko Hattori             20-1 Miyuki-cho, Otake-shi, Hiroshima Mitsubishi Rayo             Otake Office (72) Inventor Masahiro Osuka             20-1 Miyuki-cho, Otake-shi, Hiroshima Mitsubishi Rayo             Otake Office F-term (reference) 4J011 KB06 KB08 KB11 KB15 KB17                       KB29

Claims (3)

[Claims] 1. The solubility in water at 20 ° C. is 0.
A polymerizable monomer containing a polymerizable monomer of 03 mass% or less is dispersed in water using a line mixer and a homogenizer to obtain an emulsion having a volume average droplet diameter of 10.0 μm or less, A method for producing an emulsion-polymerized latex, which comprises polymerizing a polymerizable monomer in an emulsion. 2. A homogenizer having a shearing force of 1
2. The method for producing an emulsion-polymerized latex according to claim 1, wherein one having a weight of 0.0 kgf / cm ² or more is used. 3. The polymerizable monomer is selected from the group consisting of organosiloxane, 2-ethylhexyl acrylate and dodecyl methacrylate as the polymerizable monomer having a solubility in water at 20 ° C. of 0.03% by mass or less. The method for producing an emulsion-polymerized latex according to claim 1 or 2, which comprises at least one kind.