JP4627009B2 - Method for producing emulsion - Google Patents

Description

The present invention relates to an emulsion in which polymer fine particles are dispersed in an aqueous solvent. More specifically, the present invention relates to a polymer emulsion called latex or polymer colloid, in which polymer fine particles having ultraviolet absorbing ability are dispersed in an aqueous solvent.

Emulsions in which fine polymer particles are dispersed in an aqueous solvent are being studied for various uses. For example, they are used in a wide range of applications such as adhesives, coating agents, and water-based paints. It is also used as a component of diagnostic agents. In order to improve the usefulness of such a polymer emulsion, it has been studied to impart ultraviolet absorbing ability. As a result, it is possible to improve long-term weather resistance in the coating field, etc., to provide UV blocking ability, and to provide skin protection from UV rays in applications such as cosmetics and pharmaceuticals. Become. In this case, a polymer emulsion is prepared by adding an ultraviolet absorber to the emulsion or copolymerizing a polymerizable ultraviolet absorbing compound (monomer). However, the form in which the ultraviolet absorber is added to the emulsion has disadvantages such as volatilization and leakage of the ultraviolet absorber, so that there is a demand for practical use of a polymer emulsion prepared by copolymerizing a polymerizable ultraviolet absorbing compound. Yes.

As a polymer emulsion prepared by copolymerizing a conventional polymerizable ultraviolet absorbing compound, (meth) in the presence of a (meth) acryloyloxy group-containing benzotriazole-based polymerizable ultraviolet absorbing compound and a surfactant. An aqueous dispersion-type weather resistant resin composition obtained by emulsion copolymerization of a monomer mixture mainly composed of an acrylate monomer and / or a styrene monomer in an aqueous medium is disclosed. (For example, refer to Patent Document 1). For example, 2- (2'-hydroxy-5'-methacryloyloxyethylphenyl) -2H-benzotriazole is exemplified as a benzotriazole-based polymerizable ultraviolet absorbing compound. This compound (monomer) is a high melting point monomer. Yes, it is difficult to dissolve in other monomers to be copolymerized, and if it tries to dissolve, it will be in a slurry state, so the usual emulsion synthesis technique cannot be used. In Examples, after preparing and preparing a monomer emulsion by heating and emulsifying a benzotriazole-based polymerizable UV-absorbing compound in advance, polymerization is performed by dropping another monomer to be copolymerized, and an aqueous dispersion type weather resistant resin composition The product has been prepared. In this case, many surfactants are necessary for emulsification of the benzotriazole-based polymerizable UV-absorbing compound. For example, in the examples, 2- (2′-hydroxy-5′-methacryloyloxyethylphenyl)- 10.9 parts of polyoxyethylene nonylphenyl ether which is a surfactant is used with respect to 30 parts of 2H-benzotriazole.

However, in this water-dispersed weathering resin composition, the basic performance of the polymer emulsion cannot be sufficiently exhibited, and in the preparation process, a monomer, a monomer emulsion, a polymerization initiator, etc. are contained in the monomer emulsion. There was a problem that aggregates were easily formed when added. Furthermore, in the case of such a preparation method, since the monomer emulsion is first prepared, it is not applicable under the condition that the monomer remains in the monomer emulsion in a solid state. However, as in the examples, 2- (2′- When a high melting point monomer such as hydroxy-5'-methacryloyloxyethylphenyl) -2H-benzotriazole is used in a high ratio, solid content remains, and it is difficult to sufficiently polymerize this monomer. there were.

Accordingly, it is required to prepare a polymer emulsion in which polymer fine particles having ultraviolet absorbing ability are dispersed in an aqueous solvent by copolymerizing a polymerizable ultraviolet absorbing compound. However, there is room for improvement so that the polymer emulsion can be sufficiently copolymerized, and the prepared polymer emulsion can sufficiently exhibit basic performance suitable for various fields. In addition, when preparing a polymer emulsion by copolymerizing a polymerizable UV-absorbing compound, the polymer emulsion is useful in various fields as long as various monomers capable of imparting various properties to the polymer can be copolymerized. However, since it is difficult to copolymerize using a polymerizable ultraviolet absorbing compound, there is still room for improvement in this respect.
JP 2000-313705 A (1-2, p. 5)

The present invention has been made in view of the above-described situation, and is an emulsion capable of fully exhibiting the basic performance of polymer fine particles while being excellent in ultraviolet absorbing ability, and agglomeration in the polymerization step of a polymerizable ultraviolet absorbing compound. An object of the present invention is to provide a method for producing an emulsion capable of sufficiently copolymerizing monomers having various characteristics, such as the occurrence of problems.

The present inventor has made various investigations on emulsions in which polymer fine particles having ultraviolet absorbing ability are dispersed in an aqueous solvent, and those prepared by copolymerizing a polymerizable ultraviolet absorbing compound with other monomers are resistant to weathering. We focused on being able to demonstrate excellent characteristics such as persistence. And what was prepared as the emulsifier amount with respect to a monomer component being 2.5 mass% or less, Preferably it is 1.7 mass% or less can suppress the performance fall resulting from an emulsifier notably, and ultraviolet-absorbing ability It has been found that the basic performance of the polymer fine particles can be fully exhibited. That is, it has been found that when the amount of the emulsifier is within the above range, it is possible to remarkably suppress the performance degradation related to the basic performance of the ultraviolet absorption ability and the polymer fine particles. Further, the range of the emulsifier amount can be achieved by a production method characterized by dispersing a polymerizable ultraviolet absorbing compound in an aqueous solvent using a stirrer having a stepwise dispersion mechanism, In such a production method, the polymerization is carried out by dispersing and mixing in an aqueous solvent with a stirrer having a stepwise dispersion mechanism, or by a stirrer having a stepwise dispersion mechanism. By preparing an emulsion by continuously polymerizing the solution, problems such as the formation of aggregates in the polymerization process of the polymerizable UV-absorbing compound are suppressed, and monomers having various characteristics are sufficiently copolymerized. The present inventors have arrived at the present invention.

That is, the present invention provides the following general formula (1);

(In the formula, R ¹ represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms. R ² represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 8 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. Represents at least one selected from the group consisting of a cyano group and a nitro group, and R ³ represents a linear or branched alkylene group having 1 to 12 carbon atoms or —O—R ⁴ —. R ⁴ represents a linear or branched alkylene group having 2 or 3 carbon atoms, and R ⁵ represents a hydrogen atom or a methyl group. An emulsion obtained by polymerizing a polymerization solution containing components, wherein the emulsion is an emulsion prepared by setting the amount of emulsifier to 2.5% by mass or less based on the monomer component.
The present invention is described in detail below.

The present invention is an emulsion obtained by polymerizing a polymerization solution containing a monomer component essentially comprising the compound represented by the general formula (1).
Since the compound represented by the general formula (1), which is included as an essential component in the monomer component, has an ultraviolet absorbing ability of the benzotriazole group, the emulsion formed thereby exhibits an excellent ultraviolet shielding effect. Will do. The emulsion includes not only a polymerization solution and aqueous polymerization but also an emulsion obtained by phase conversion after solution polymerization.

The emulsion is prepared with the amount of the emulsifier with respect to the monomer component being 2.5% by mass or less, preferably 1.7% by mass or less. By setting the amount of the emulsifier within this range, the ultraviolet absorbing ability is excellent and the basic performance of the polymer fine particles can be sufficiently exhibited. In addition, when using an emulsion, the occurrence of problems such as foaming can be suppressed, handling becomes easy, and when used for applications such as a coating agent, the drying property and stability of the coating film are excellent. Can be.
The amount of the emulsifier is the amount of the emulsifier used in the emulsification of the monomer component in the emulsion preparation process. In addition, when prepared by emulsion polymerization, it is the amount of emulsifier used to emulsify and polymerize the monomer component, but when emulsifying after preparing the polymer to produce an emulsion , The amount of emulsifier used for emulsification of the polymer. As described above, the emulsion of the present invention includes not only a form prepared by emulsion polymerization but also a form in which an emulsion is prepared by emulsifying after preparing a polymer. In any case, the amount of the emulsifier in the present invention is indicated by the amount (% by mass) of the emulsifier used in the emulsion preparation step on the basis of 100% by mass of the monomer component.

In the case of the synthesis method of the present invention, the amount of emulsifier used can be reduced as compared with the conventional batch synthesis method. Therefore, when using an emulsifier, it is preferable to set it as 0.1-2.5 mass%, More preferably, it is 0.1-1.7 mass%. The use ratio of the emulsifier shown here is generally applicable in the case of a polymer emulsion having a solid content ratio of 40% or more. Depending on the monomer composition and the solid content ratio, the emulsifier can be used in the range of 0.1 to 1% by mass and more preferably in the range of 0.1 to 0.5% by mass in terms of reducing the amount of the emulsifier used. The range of the amount of emulsifier used here is a reactive emulsifier that reacts during polymer formation and becomes a constituent residue (element) of the polymer molecule, and does not cause a polymerization reaction during polymer formation and does not become a constituent residue of the polymer molecule Applicable to each normal emulsifier. Moreover, when using 2 or more types of emulsifiers, you may apply to the total usage-amount. In the case of using a reactive emulsifier and a normal emulsifier, the amount used can be 5% by mass or less or 3% by mass or less, etc., exceeding the range described in the previous paragraph. However, when these emulsifiers are used in a large amount, there is a concern about deterioration of the properties of the polymer emulsion. However, when a reactive emulsifier is used positively as a constituent residue of a polymer, it may be used beyond the scope of this paragraph and the previous paragraph.
In order to reduce the influence of the emulsifier, it is a preferable choice to use the reactive emulsifier in the range of 0.1 to 2.5% by mass or in the range of the lower ratio mentioned above. That is, when the polymer emulsion can be prepared, the ratio of the free reactive emulsifier is theoretically 0% by mass.
In the present invention, it is also a preferable choice to prepare an emulsion without using an emulsifier, and the amount of the emulsifier used is 0.1% by mass or less or equivalent to or less than the impurities in the monomer. It is also a preferred choice to prepare an emulsion with

Among the above-mentioned emulsifiers, for example, an anionic surfactant, a nonionic surfactant, a cationic surfactant, and an amphoteric surfactant are suitable as the normal emulsifier, and the reactive emulsifier is a reactive surfactant. Agents are preferred. Polymeric surfactants are also used, but can react or act as reactive or normal emulsifiers depending on the monomer composition. Usually, it is preferable to use one or more emulsifiers.
Examples of the anionic surfactants include alkyl sulfate salts such as sodium dodecyl sulfate, (sodium lauryl sulfate), ammonium dodecyl sulfate (ammonium lauryl sulfate); sodium dodecylbenzenesulfonate, ammonium dodecylbenzenesulfonate, dodecylnaphthalenesulfonate Alkyl aryl sulfonates such as sodium; polyoxyethylene alkyl sulfonate (commercially available, for example, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., product name: Hytenol 18E); polyoxyethylene alkyl aryl sulfonate ( Commercially available products include, for example, Daiichi Kogyo Seiyaku Co., Ltd., product name: Hytenol N-08, etc.); dialkyl sulfosuccinate; aryl sulfonic acid formalin condensate; ammonium dodecylate, stearic acid Thorium, potassium oleate, fatty acid salts such as castor oil potassium soap; and the like.

Examples of the nonionic surfactant include polyoxyethylene alkyl ether (commercially available, for example, Sanyo Kasei Kogyo Co., Ltd., product name: NAROACTY N-200); polyoxyethylene alkyl aryl ether (commercially available) For example, Sanyo Kasei Kogyo Co., Ltd., product name: Nonipol-200, etc.); polyethylene glycol and polypropylene glycol condensate; sorbitan fatty acid ester; polyoxyethylene sorbitan fatty acid ester; fatty acid monoglyceride; polyamide; A condensation product of an aliphatic amine; and the like.
Examples of the cationic surfactant include salts of alkylamines such as dodecyl ammonium chloride, coconut amine acetate, and stearyl amine acetate; quaternary ammonium such as lauryl trimethyl ammonium chloride, stearyl trimethyl ammonium chloride, and cetyl trimethyl ammonium chloride. Examples include salts.

Examples of the reactive surfactant include polyoxyethylene alkylpropenyl phenyl ethers (for example, Aqualon RNs, Patent 2651736 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and sulfuric acid thereof having various molecular weights (different number of moles of ethylene oxide added). Salt (for example, Aqualon HS manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., Aqualon BC Patent No. 2652459, Aqualon BC1025 used in Examples) and polyoxyethylene alkyl ether sulfates having an allyl (oxy) group introduced (For example, Aqualon KHs manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd. Patent 2596441), polyethylene glycol mono (meth) acrylate, polyoxyethylene / alkylphenol ether (meth) acrylic acid ester, 2- (meth) acryloyloxye Ammonium Rusuruhon acid, mono-maleic acid esters and derivatives thereof and polyoxyalkylene alkyl ether phosphate esters of polyoxyethylene glycol, and the like.
Examples of the amphoteric surfactant include alkylbetaines such as lauryl betaine, stearyl betaine, lauryl dimethylamine oxide, and alkylamine oxide type emulsifiers.
Examples of the polymer surfactant include poly (meth) acrylates such as sodium polyacrylate; polyvinyl alcohol; polyvinylpyrrolidone; polyhydroxyalkyl (meth) acrylates such as polyhydroxyethyl acrylate; or polymers thereof. A copolymer having one or more of the polymerizable monomers constituting the copolymer as a copolymer component; and the like, and “DM-1N” used in the examples is an example.

The emulsion is preferably prepared with a monomer component ratio in the polymerization solution of 40% by mass or more. That is, in the emulsion preparation step, the emulsion of the present invention has a monomer component ratio (monomer concentration) in the polymerization solution based on 100% by mass of the polymerization solution composed of the monomer component and the solvent. It is preferable to be prepared as described above. Thereby, for example, in coating applications, the drying property of the emulsion is improved, and even when thinly coated, the ratio of the polymer particles in the emulsion is large, and therefore, represented by the general formula (1). The ultraviolet absorbing ability by the compound is sufficiently exhibited. In addition, the characteristics of other polymer particles can be efficiently and sufficiently exhibited. More preferably, it is 40-60 mass%, More preferably, it is 45-60 mass%.

The molecular weight distribution of the emulsion tends to be relatively wide as measured by gel filtration chromatography (GPC). The ratio (Mw / Mn) between the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the emulsion is usually 2 or more even if it is unimodal on the GPC chart, and it is 3 or more depending on the monomer composition and reaction conditions. Some may show 10 or more, or even 50 or more. In the case of bimodality (multimodality), the molecular weight distribution as a whole often shows a value of 10 or more, or even 50 or more. It should be noted that since the molecular weight is high as in Example 1 (Mw 7 million, Mn 6.1 million) and Example 2 (Mw 73 million, Mn 64,000,000), it reaches the limit of the separation performance of the GPC column, so apparently Mw / Mn Sometimes near 1. Even in this case, since the slope of the peak of the GPC chart was gentle compared to the case of the molecular weight standard sample, it was confirmed that the molecular weight distribution was wide. When the molecular weight distribution of the emulsion is in the above range, the effects of the present invention are sufficiently exhibited, but may be in a range different from the above depending on the use of the emulsion.

(Gel filtration chromatography (GPC) measurement conditions)
The synthesized polymer emulsion was dissolved in tetrahydrofuran (THF) to a polymer concentration of 0.15 to 0.2%, filtered through a microfilter having a pore size of 0.45 μm, and analyzed by GPC. In this measurement, an HLC-8120GPC type apparatus equipped with a TSK-GEL G5000HXL or TSK-GEL CMHXL-L column manufactured by Tosoh Corporation was used, and THF was used as a solvent. The control of the apparatus and the analysis of the weight average molecular weight (Mw) and the number average molecular weight (Mn) were performed using GPC-8020 model II software and polystyrene as the molecular weight standard.

The emulsion is obtained by polymerizing a polymerization solution containing a monomer component essentially containing the compound represented by the general formula (1). Examples of the compound represented by the general formula (1) include 2- [2′-hydroxy-5 ′-(meth) acryloyloxymethylphenyl] -2H-benzotriazole, 2- [2′-hydroxy-5′- (Meth) acryloyloxyethylphenyl] -2H-benzotriazole, 2- [2′-hydroxy-5 ′-(meth) acryloyloxypropylphenyl] -2H-benzotriazole, 2- [2′-hydroxy-5′- (Meth) acryloyloxyhexylphenyl] -2H-benzotriazole, 2- [2′-hydroxy-3′-tert-butyl-5 ′-(meth) acryloyloxyethylphenyl] -2H-benzotriazole, and 2- [2′-hydroxy-5 ′-(β- (meth) acryloyloxyethoxy) -3′-tert-butylphenol L] -5-tert-butyl-2H-benzotriazole: 2- [2'-hydroxy-5 '-(methacryloyloxyethoxyethyl) phenyl] -2H-benzotriazole (UV absorbing monomer manufactured by Otsuka Chemical Co., Ltd.) Product name: RUVA-93 (hereinafter referred to as “RUVA-93”). 2- [2′-hydroxy-5 ′-(methacryloyloxyethoxyethyl) phenyl] -2H-benzotriazole (RUVA-93) is more preferable. These may be used alone or in combination of two or more.

As said monomer component, the compound represented by the said General formula (1) is included essential. As the ratio, it is preferable that it is 25 mass% or more with respect to all the monomer components. When the content is less than 20% by mass, an emulsion obtained by polymerizing a polymerization solution containing a monomer component essentially containing the compound represented by the general formula (1) cannot sufficiently exhibit an ultraviolet shielding effect. There is a fear. More preferably, it is 35 mass% or more, More preferably, it is 45 mass% or more.

The monomer component may contain other compounds as long as the compound represented by the general formula (1) is included as an essential component. By including other compounds, particularly various monomers that can be copolymerized, various properties can be imparted to the emulsion, and the polymer emulsion can exhibit useful properties in various fields.
Examples of the other compounds include (i) a compound having an ultraviolet absorption effect, (ii) a compound having an effect of capturing or erasing radicals generated by ultraviolet rays (hereinafter referred to as a monomer having an ultraviolet stabilizing group), (Iii) It is preferable that it is 1 type (s) or 2 or more types, such as another polymerizable monomer.
As the compound (i) having an ultraviolet absorption effect, the following general formula (2);

(Wherein, ^{R 1} and ^{R 5,} .R ⁶ is the same as ^{R 1} and ^{R 5} in the general formula (2) is 1 to 12 carbon atoms linear or branched chain alkylene R ⁷ represents a hydrogen atom or a hydroxyl group, and R ⁸ represents a hydrogen atom or an alkoxy group having 1 to 6 carbon atoms. The branched chain includes those in which the carbon-carbon bond is branched instead of being linear, and may be branched and branched.

The benzophenone compound represented by the general formula (2) is not particularly limited, and examples thereof include 2-hydroxy-4- [2- (meth) acryloyloxy] ethoxybenzophenone, 2-hydroxy-4- [2- ( (Meth) acryloyloxy] butoxybenzophenone, 2,2'-dihydroxy-4- [2- (meth) acryloyloxy] ethoxybenzophenone, 2-hydroxy-4- [2- (meth) acryloyloxy] ethoxy-4 '-( 2-hydroxyethoxy) benzophenone, 2-hydroxy-3-tert-butyl-4- [2- (meth) acryloyloxy] ethoxybenzophenone, and 2-hydroxy-3-tert-butyl-4- [2- (meta ) Acrylyloxy] butoxybenzophenone or more Can be.

As the compound (i) having an ultraviolet absorption effect, the following general formula (3);

(Wherein R ⁵ represents the same meaning as R ⁵ in the general formula (2). R ⁹ represents a direct bond, — (CH ₂ CH ₂ O) _n — or —CH ₂ CH (OH) —). Represents CH ₂ O—, n is an integer of 1 to 5. R ^{10 to} R ¹⁷ are the same or different and are a group consisting of a hydrogen atom, an alkoxy group having 1 to 10 carbon atoms, an alkenyl group, and an alkyl group. The compound represented by 1 or more types selected from more is preferable.

The triazine compound represented by the general formula (3) is not particularly limited, and examples thereof include 2,4-diphenyl-6- [2-hydroxy-4- (2-acryloyloxyethoxy)]-s-triazine, 2,4-bis (2-methylphenyl) -6- [2-hydroxy-4- (2-acryloyloxyethoxy)]-s-triazine and 2,4-bis (2-methoxyphenyl) -6- One type or two or more types such as [2-hydroxy-4- (2-acryloyloxyethoxy)]-s-triazine can be suitably used.

Although it does not specifically limit as said (ii) monomer which has a ultraviolet-ray stable group, For example, the monomer of piperidine represented by the following general formula (4) and (5) is mentioned preferably.

In the formula, R ¹⁸ represents a hydrogen atom or a cyano group. R ¹⁹ and R ²⁰ are the same or different and each represents a hydrogen atom or a methyl group. R ²¹ represents a hydrogen atom or a hydrocarbon group. R ²² represents an oxygen atom or an imino group.

^Wherein, R 18 ^{to R 20} and ^{R 22} are the same as ^R 18 ^{to R 20} and ^{R 22} in the general formula (5). R ²³ and R ²⁴ are the same or different and each represents a hydrogen atom or a methyl group.

The monomer represented by the general formula (4) is not particularly limited. For example, 4- (meth) acryloyloxy-2,2,6,6-tetramethylpiperidine, 4- (meth) acryloylamino-2 , 2,6,6-tetramethylpiperidine, 4- (meth) acryloyloxy-1,2,2,6,6-pentamethylpiperidine, 4- (meth) acryloylamino-1,2,2,6,6 -Pentamethylpiperidine, 4-cyano-4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 4-crotonoyloxy-2,2,6,6-tetramethylpiperidine, and 4 -One or more of crotonoylamino-2,2,6,6-tetramethylpiperidine and the like are preferable.

The monomer represented by the general formula (5) is not limited. For example, 1- (meth) acryloyl-4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 1- (Meth) acryloyl-4-cyano-4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine and 1-crotonoyl-4-crotonoyloxy-2,2,6,6-tetra Methyl piperidine and the like are preferable. These may be used alone or in combination of two or more.

As said (iii) other polymerizable monomer, what is necessary is just a monomer copolymerizable with the said General formula (1), and the 1 type (s) or 2 or more types of the following monomers are suitable. As such a monomer, monomers having a carboxyl group such as (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid and maleic anhydride, and metal salts thereof are preferable. Examples of the metal salt include Na salt, K salt, NH ₄ salt, Mg salt, Ca salt, Sr salt, Zn salt, Zr salt and Al salt. Specifically, sodium (meth) acrylate, ( (Meth) potassium acrylate, (meth) ammonium acrylate, (meth) magnesium acrylate, (meth) calcium acrylate, (meth) strontium acrylate, (meth) zinc acrylate, (meth) zirconium acrylate, (meta ) Aluminum acrylate, sodium itaconate, potassium itaconate, ammonium itaconate, magnesium itaconate, calcium itaconate, strontium itaconate, zinc itaconate, zirconium itaconate, aluminum itaconate, sodium maleate, potassium maleate, malein Ammonium acid, maleic acid Magnesium, calcium maleate, strontium maleate, zinc maleate, zirconium maleate, aluminum maleate, sodium fumarate, potassium fumarate, ammonium fumarate, magnesium fumarate, calcium fumarate, strontium fumarate, zinc fumarate, Zirconium fumarate and aluminum fumarate are preferred.

As the monomer, in addition to the monomer having a carboxyl group, one or more of the following monomers are preferable.
Acidic phosphate ester monomers such as 2- (meth) acryloyloxyethyl acid phosphate; 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate and hydroxyl-terminated flexible (meth) acrylate (for example, Daicel Monomers having a group having active hydrogen such as Chemical Industry Co., Ltd., product name: Plaxel FM); (meth) acrylamide, N, N-dimethylaminomethyl (meth) acrylate, imide (meth) acrylate and N-methylol Nitrogen-containing monomers such as (meth) acrylamide.

Monomers having two polymerizable double bonds such as ethylene glycol di (meth) acrylate; halogen-containing monomers such as vinyl chloride; aromatic monomers such as styrene and α-methylstyrene; vinyl ether; methyl 3-methoxyacrylate ( _{CH 3 O-CH = CHCOOCH 3} ); the following general formula (6);

(Wherein R ²⁵ represents a hydrogen atom or a methyl group; R ²⁶ represents a hydrocarbon group having 1 or more carbon atoms).

In the general formula (6), the substituent represented by R ²⁶ (hydrocarbon group having 1 or more carbon atoms) is not particularly limited, and for example, the substituents exemplified below are preferable.
An alicyclic hydrocarbon group having 4 or more carbon atoms such as cyclopentyl group, cyclohexyl group, methylcyclohexyl group and cyclododecyl group; methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, A linear or branched alkyl group having 4 or more carbon atoms such as 2-ethylhexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, pentadecyl group, hexadecyl group and octadecyl group.

Polycyclic hydrocarbon group having 4 or more carbon atoms such as bornyl group and isobornyl group; benzyl group, glycidyl group, tetrahydrofurfuryl group, furfuryl group, 2-hydroxyethyl group, 2-phenoxyethyl group, 2- (acetoacetoxy group) ) Aromatic rings and oxygen such as ethyl group, N, N-dimethylaminoethyl group, N, N-diethylaminoethyl group, 2-hydroxypropyl group, 3-hydroxypropyl group, 2-hydroxybutyl group and 4-hydroxybutyl group Hydrocarbon groups having a partial structure of atoms, nitrogen atoms, sulfur atoms, phosphorus atoms, etc .; Carbonizations having halogen atoms such as trifluoroethyl group, tetrafluoropropyl group, octafluoropentyl group and heptadodecafluorodecyl group in the partial structure A hydrogen group; and the like are preferable. Of these, an alicyclic hydrocarbon group, a branched alkyl group, and a linear alkyl group having 6 or more carbon atoms are more preferable.

Although it does not specifically limit as a monomer represented by the said General formula (6), For example, the compound illustrated below is suitable.
Methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) Acrylate, amyl (meth) acrylate, isoamyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, tert-butylhexyl (Meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, dodecyl (meth) acrylic Over DOO, pentadecyl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate and isostearyl (meth) acrylate of (meth) acrylic acid (lower, intermediate, higher) alkyl esters.

Benzyl (meth) acrylate, dicyclopentyl (meth) acrylate, bornyl (meth) acrylate, isobornyl (meth) acrylate, cyclohexyl (meth) acrylate, methylcyclohexyl (meth) acrylate, cyclododecyl (meth) acrylate, cyclopentyl (meth) acrylate 2-hydroxyethyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, 2-phenoxyethyl (meth) acrylate, 2- (acetoacetoxy) ethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) Acrylate, N, N-diethylaminoethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl Meth) acrylate, 4-hydroxybutyl (meth) acrylate.

Trimethylolpropane (meth) acrylate, glycidyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, furfuryl (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, tetraethylene glycol (meth) acrylate, tripropylene glycol (meth) acrylate 1,4-butanediol (meth) acrylate, 1,6-hexanediol (meth) acrylate, 1,9-nonanediol (meth) acrylate, neopentyl glycol (meth) acrylate, neopentyl glycol hydroxypivalate ester ( (Meth) acrylate, pentaerythritol tri (meth) acrylate, 2- (meth) acryloyloxypropyl hydrogen phthalate, trimethylol Lopanethoxytri (meth) acrylate, 2-propenoic acid [2- [1,1-dimethyl-2-[(1-oxo-2-propenyl) oxy] ethyl] -5-ethyl-1,3-dioxane -5-yl] methyl ester (manufactured by Nippon Kayaku Co., Ltd., trade name: KAYARAD R-604), trifluoroethyl (meth) acrylate, tetrafluoropropyl (meth) acrylate, octafluoropentyl (meth) acrylate and heptadodecafluoro Decyl (meth) acrylate and the like are preferable.

Among these, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate , Octyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, 2 -Hydroxypropyl (meth) acrylate and trimethylolpropane (meth) acrylate are more preferred. These may be used alone or in combination of two or more.

The ratio of the compound (i) having an ultraviolet absorption effect, (ii) the monomer having an ultraviolet stabilizing group, and (iii) other polymerizable monomer is as follows: Is preferably 0 to 30% by mass, (ii) is 0 to 15%, and (iii) is the balance.

Depending on the purpose of use, the emulsion may contain various additives as necessary.
Examples of the additives include curing agents such as polyfunctional isocyanates and polyfunctional hydrazines, film forming aids, pigments, dispersants, thickeners, preservatives, fillers, antistatic agents, and matting agents. Is mentioned. Further, since the emulsion contains water and organic matter, microorganisms such as mold may grow. In order to prevent quality deterioration due to microorganisms, various known bacteriostatic agents and bactericides may be used as the additive. Among the hydrophilic organic solvents described above, there are those having bacteriostatic action and bactericidal action such as ethyl alcohol, so such hydrophilic organic solvent is used for the whole of the aqueous solvent, for example, By blending 15 to 40% by weight, preferably 20 to 30% by weight, the same effect as when a bacteriostatic agent or the like is added can be obtained.
Moreover, you may perform washing | cleaning, solid content adjustment, viscosity adjustment, etc. with respect to the said emulsion.

The present invention is also a method for producing the emulsion, wherein the production method comprises a polymerization solution containing a monomer component essentially comprising the compound represented by the general formula (1) and an aqueous solvent, and an initiation. It is also a method for producing an emulsion, which comprises a step of preparing an emulsion with an agent as an essential component and using a stirrer equipped with a stepwise dispersion mechanism to disperse the compound represented by the general formula (1) in an aqueous solvent.
The advantages of the emulsion production method of the present invention will be described in contrast to the emulsion production method different from the present invention.

In the method for producing an emulsion, it is usually necessary to sufficiently emulsify the monomer in the preparation of the monomer emulsion in order to add the monomer emulsion after the initial reaction. However, when using a monomer having an ultraviolet absorbing ability such as the compound represented by the general formula (1), since the monomer has a high melting point and is hardly soluble in other monomers, The amount could not be reduced. Furthermore, since it was necessary to prepare the monomer emulsion first, it was not possible to apply conditions such that the monomer remained solid. Therefore, for example, when a high melting point monomer is used in a high ratio, it is difficult to polymerize because a solid content remains. In addition to these problems, a problem that aggregates are easily formed when a monomer, a monomer emulsion, a polymerization initiator, or the like is added to the polymerization solution is often observed.

When preparing a monomer emulsion by fully dispersing the compound represented by the general formula (1), for example, a method using a perforated plate cannot be used for a monomer mixture having a solid content. Moreover, when solid substance precipitates in a perforated plate, there is concern about the durability of the apparatus. When using a static mixer, it is difficult to disperse unless the flow velocity is increased. There is a possibility that the amount of energy input can be reduced, but it has been necessary to solve the problem that the apparatus becomes expensive because it flows through the flow path under high pressure conditions.

On the other hand, in the method for producing an emulsion of the present invention, a monomer emulsion can be prepared by sufficiently dispersing the compound represented by the general formula (1) to produce an emulsion. Problems such as the formation of aggregates in the polymerization step of the compound are suppressed, and in addition to the polymerizable UV-absorbing compound, monomers having various characteristics can be sufficiently copolymerized. These advantages are summarized as follows.

(1) As a feature of this method, since a high melting point monomer can be charged and dispersed with low energy (in the case of Examples, about 1 Whr / L), it is easy to use the high melting point monomer, and the aggregate Less precipitates.
(2) Emulsion synthesis using a high melting point monomer in a suspended state can be performed.
(3) In the method of preparing an emulsion using a high melting point monomer, the emulsion can be synthesized even under low surfactant conditions.

(4) As will be described later, when continuous synthesis is performed, scale-up becomes easy, which is advantageous as an industrial production method.
(5) Excellent in terms of safety. That is, as will be described later, when emulsion polymerization is performed using a tube (tubular reactor), a portion with particularly large heat generation is performed in the tube, so heat removal during polymerization is easy and reaction heat is generated. The volume of the large portion is limited and the reaction temperature can be easily controlled. As a result, it is possible to perform a stable operation equivalent to batch charging with a monomer concentration (NV) of, for example, 40 to 45% by mass.

The method for producing the emulsion includes a polymerization solution containing a monomer component essential to the compound represented by the general formula (1) and an aqueous solvent, and a step of preparing the emulsion essentially comprising an initiator. It is preferable.
Compared to common organic solvents, water has a large specific heat and heat of vaporization. For this reason, by using an aqueous solvent for the reaction, there is an advantage that the temperature rise due to the generation of reaction heat does not easily occur, and even if the generation of reaction heat becomes too large, a mild boiling level is sufficient. . The aqueous solvent is not particularly limited as long as it contains water, and a hydrophilic organic solvent or the like can be used in combination as necessary.

Examples of the hydrophilic organic solvent include lower monohydric alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, butyl alcohol and 2-butyl alcohol; ethylene glycol, diethylene glycol, propylene glycol, butanediol and glycerol. Lower divalent or lower polyhydric alcohols such as acetone; lower ketones such as acetone, methyl ethyl ketone, and cyclohexanone; ethers that can be mixed with water such as 1,2-dimethoxyethane, tetrahydrofuran, and dioxane at an arbitrary ratio; Species or two or more are preferred.

When the hydrophilic organic solvent is used in combination with water, the blending ratio of the hydrophilic organic solvent may be appropriately set according to the purpose of use of the obtained emulsion, and is preferably 90% by weight or less. If it exceeds 90% by weight, it should be practically handled as an organic solvent, and an aqueous emulsion may not be prepared. More preferably, it is 70 weight% or less, More preferably, it is 50 weight% or less, Most preferably, it is 30 weight% or less. Considering the characteristics as an aqueous solvent, it is preferably 50% by weight or less, and preferably 20% by weight or less for the purpose of use in which a small amount of volatile organic components is desired. In consideration of environmental aspects, it is particularly preferably 10% by weight or less, and most preferably not blended (0% by weight).

The usage-amount of an aqueous solvent can be suitably set depending on the monomer component to be used, an initiator, a polymerization solution, etc. Preferably, it is 70% by weight or less, preferably 60% by weight or less, and more preferably 60 to 40% by weight with respect to the polymerization solution (reaction mixture).
The polymerization solution may contain other components such as a chain transfer agent and an initiator as long as it contains the monomer component and the aqueous solvent.

The initiator is not particularly limited as long as it exhibits the effects of the present invention, and among them, a polymerization initiator is preferable. Examples of the polymerization initiator include 2,2′-azobis- (2-methylbutyronitrile), 2,2′-azobisisobutyronitrile, 2,2-azobis (2-diaminopropane) hydrochloride, and the like. Azo polymerization initiators; persulfates such as ammonium persulfate, sodium persulfate and potassium persulfate; hydrogen peroxide, ascorbate, tert-butylperoxy-2-ethylhexanoate, benzoyl peroxide and di- 1 type (s) or 2 or more types, such as normal radical polymerization initiators, such as redox type | system | group polymerization initiators, such as tert- butyl peroxide;

The usage-amount of the said polymerization initiator will not be specifically limited if it is the range which can prepare the emulsion of this invention suitably, For example, it is preferable that it is 0.05 to 2 weight% with respect to a monomer component. If the amount is less than 0.05% by weight, the polymerization rate becomes slow, and aggregates of polymer fine particles are likely to be formed. In addition, unreacted monomers may easily remain. In addition, the physical properties of the polymer fine particles may be adversely affected. More preferably, it is 0.1 to 1% by weight.

In the above polymerization reaction, if necessary, n-dodecyl mercaptan, tert-dodecyl mercaptan, n-butyl mercaptan, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropylmethyldiethoxy At least one chain transfer agent such as silane, (CH ₃ O) ₃ Si—S—S—Si (OCH ₃ ) ₃ , and (CH ₃ O) ₃ Si—S ₄ —Si (OCH ₃ ) ₃ is used. The molecular weight of the resulting polymer can also be adjusted within the range that does not impair the effects of the present invention. Similarly, known additives such as a pH buffering agent, a chelating agent, and a film forming aid may be used as long as the effects of the present invention are not impaired.

This invention is also a manufacturing method of the emulsion which disperse | distributes the compound represented by the said General formula (1) in an aqueous solvent using the stirrer provided with a stepwise dispersion mechanism. In such a dispersion step, the monomer component essentially comprising the compound represented by the general formula (1) is monodispersed as fine particles (droplets) in the aqueous solvent by stirring force. It is preferred to prepare a so-called monomer emulsion.
The stirrer having the stepwise dispersion mechanism has a function of dispersing the compound represented by the general formula (1) in an aqueous solvent through a plurality of steps, and the dispersion proceeds stepwise. It is preferable. By promoting the dispersion stepwise, the energy consumption can be reduced, the use of a high melting point monomer is facilitated, and there is an advantage that the precipitation of aggregates is reduced.

In the dispersion step, a monomer emulsion can be prepared from the monomer component using the stirrer. However, in the dispersion step of the monomer component, a known dispersion technique can be used in combination as necessary. it can. Examples of such a dispersion technique include a method of ejecting from a small hole or a small gap such as an orifice or a slit, a method of applying vibration by sound waves or ultrasonic waves, and a sphere such as glass, ceramic, metal and resin (small sphere). And beads).
The time of the dispersion step and the magnitude of the stirring force are appropriately set according to various methods so that the fine particles of the monomer component in the monomer emulsion to be prepared satisfy a desired range in the particle size and the like. There is no limitation.

When the monomer component is monodispersed in the aqueous solvent by the above stirring, as a method of mixing the aqueous solvent and the monomer component, for example, the monomer component is added to the aqueous solvent in advance before stirring. A method of mixing, a method of adding monomer components to a stirring aqueous solvent sequentially (continuous addition and / or intermittent addition), and a mixing of the aqueous solvent and the monomer components in a desired ratio. However, the method is not limited to these methods. In the production method of the present invention, it is preferable to use the above stirrer. In this case, a method in which the aqueous solvent and the monomer are separately added and mixed separately at a desired ratio may be applied.

The monomer component used in the stirrer having the above-described stepwise dispersion mechanism may be a state where the aqueous solvent and the monomer component are simply combined (a state of mutual separation). The monomer component may be preliminarily emulsified or coarsely emulsified so as to be fine particles having a desired particle diameter by an arbitrary method such as stirring, and the monomer component may be contained in the aqueous medium. It may be in a state where the liquid droplets are stirred to such an extent that they can be confirmed with the naked eye.

In the preparation of the monomer emulsion, the particle size of the monodispersed monomer component fine particles is not limited, and polymer fine particles having a desired particle size are synthesized in consideration of the use and physical properties of the polymer emulsion. What is necessary is just to set suitably, for example, 0.02-10 micrometers is preferable at an average particle diameter, More preferably, it is 0.05-5 micrometers, More preferably, it is 0.08-5 micrometers, Most preferably, it is 0.08- 2.5 μm. The coefficient of variation of the particle size of the monodispersed monomer component fine particles is not limited as in the case of the above particle size, but is preferably 30% or less, more preferably 20% or less, and still more preferably 15%. % Or less.

The method for producing an emulsion of the present invention is prepared by using a polymerization solution and an initiator as essential. The initiator may be allowed to coexist with the monomer emulsion in the monomer emulsion preparation process (dispersion step) or after the monomer emulsion preparation (after the dispersion step). Among these, it is preferable to make it coexist with a monomer emulsion in the preparation process (dispersion process) of a monomer emulsion. The polymerization reaction starts due to the presence of the initiator, but when the initiator is added during the dispersion step, the initiator is also sufficiently dispersed and mixed, so compared to the case where it is added after the dispersion step, The local concentration of the initiator can be lowered, and the possibility that the polymerization reaction proceeds at a portion where the initiator concentration is locally high can be reduced. Thus, the embodiment in which the production method is a method for producing an emulsion in which an initiator is dispersed in an aqueous solvent with a stirrer having a stepwise dispersion mechanism together with the compound represented by the general formula (1) is also provided. This is one of the preferred embodiments of the present invention.

The production method is preferably an emulsion production method in which an emulsion is prepared by continuously polymerizing a polymerization solution dispersed by a stirrer having a stepwise dispersion mechanism. When the polymerization is carried out continuously, it is easy to scale up, which is advantageous as an industrial production method. Continuous polymerization means that the polymerization is not directly mixed with the reaction mixture in which the polymerization reaction proceeds with the polymerization of the monomer emulsion following the preparation of the monomer emulsion or simultaneously with the polymerization of the monomer emulsion (polymerization reaction time 0). Refers to the reaction mode. In contrast, in a normal batch operation, the unpolymerized monomer emulsion is directly mixed with the reaction mixture in which the polymerization reaction has proceeded. Even in the case of batch type, the monomer emulsion is polymerized in the stirring device, and the reaction rate estimated from the state of generation of reaction heat is usually 25% or more, preferably 50% or more, more preferably 75% or more. It is. In the case of the example, it is estimated to be 80% or more. In addition, the presence or absence of stirring does not matter as long as the polymerization reaction is performed while the monodispersed state of the monomer component is maintained. The polymerization reaction conditions and the like may be appropriately selected from known polymerization methods and conditions according to the type of monomer used. Among these, the radical polymerization method is preferable because it is simple and efficient.

The polymerization reaction can be carried out in a stirrer equipped with a stepwise dispersion mechanism or in a reaction vessel connected to the stirrer. A reaction vessel for such a polymerization reaction may be any vessel that continuously polymerizes a dispersed polymerization solution to prepare an emulsion, and is basically a tube type. In an actual apparatus, the initial polymerization reaction stage to the late polymerization reaction (ripening) stage may be performed consistently in a tubular reactor as basic, but the initial polymerization reaction stage is performed in a stirrer for most reactions. An operation in which the late polymerization reaction is performed in a large-diameter reaction tube or reaction tank after heat is generated in a small-volume tubular portion is also possible. It is also preferable to attach a slight tubular reactor (reaction tube) to the stirrer and cause the polymerization reaction to be carried out in the tubular reactor, and to carry out an aging step in the reaction vessel in which a slight amount of remaining monomer is reduced to a predetermined amount. Is a choice. In any of these forms, not only is it easy to suppress the formation of aggregates, but also a polymerization reaction is carried out in the tube, so it is easy to remove the heat generated by the polymerization, and the amount of reaction heat generated is large. The volume is limited and the reaction temperature can be easily controlled, which is excellent in terms of safety. As a result, it is possible to perform operations equivalent to batch charging while increasing the monomer concentration to 40 to 45 mass%, for example.
The polymerization vessel is preferably a hollow tube, and other devices such as a static mixer for stirring the reaction mixture may be installed.

In the above polymerization reaction, the reaction temperature is preferably in the range of room temperature to 100 ° C. under normal pressure conditions. Considering the reaction rate, it is more preferably 70 to 100 ° C, and further preferably 85 to 100 ° C.

The polymerization reaction time means the time (holding time) from the start of polymerization to completion of ripening, and the polymerization reaction can be completed efficiently depending on the type and composition of the monomer used, the type of polymerization initiator, and the like. For example, it is realistic to set 0.1 to 8 hours from the start to the end of the polymerization. The shorter the holding time, the higher the productivity of the apparatus. Therefore, it is preferable to shorten the holding time, for example, 0.1 to 1 hour. In order to facilitate the polymerization at the time of the above polymerization, it is generally preferable to use a raw material such as a polymerization initiator, a monomer or water by deoxidizing under an inert gas atmosphere such as nitrogen or under reduced pressure, When the temperature of the aqueous medium is near its boiling point, almost no dissolved oxygen is present, so that the polymerization can be carried out without deoxygenation in advance.

Below, the suitable example of the apparatus (stirrer) which manufactures the emulsion of this invention is shown. The stirrer is composed of a plurality of stirring blades, a fixed shaft that fixes the stirring blades, and a motor that drives the stirring blades through the fixed shaft, and has a raw material supply port, an initiator supply port, and a discharge port. It is.
In the production method of the present invention, for example, the raw material containing the monomer and water is mixed and dispersed stepwise or continuously while passing the mixture containing the aqueous solvent and the monomer from one end of the stirrer to the other end. become. A “supply pipe” is connected to the raw material supply port, and the raw material is injected from a raw material tank or a pump attached to the “supply pipe”.

The stirrer is a stirrer provided with components having stirring ability inside a cylindrical container, and more specifically, a “cylindrical container” and a rotation provided along the central axis of the cylindrical container. A possible "fixed shaft" and a plurality of "stirring blades" fixed to the fixed shaft at a predetermined interval in the vertical direction, and the stirring blade rotates by rotating the fixed shaft This is a stirrer characterized by that. By passing a mixture containing an aqueous solvent and a monomer from one end to the other end of the cylindrical container, a liquid in which the monomer fine particles are monodispersed in the aqueous solvent (that is, a monomer emulsion) is continuously formed. Can get to.
As said supply piping, if it is piping which can supply the mixture containing an aqueous solvent and a monomer to one end (raw material supply port) of a stirrer, about the material and form (shape, length, etc.), what There is no limitation, and it can select and employ | adopt suitably. For example, a pipe made of a material having excellent thermal conductivity may be used so that the mixture can be easily heated in the pipe, or the aqueous solvent and the monomer may be supplied through different pipes, or the pipes may be connected in the middle. You may merge. Moreover, the said piping may be equipped with the apparatus etc. which can be heated from the outside, or a structure or a mechanism.

Specific examples of the agitator include the agitator shown in FIG.
In FIG. 1, the stirrer which has the raw material supply port 4 (one end) and the initiator supply port 5 is shown. In the stirrer, a plurality of stirring blades 3 are disposed in the cylindrical container 7 in a direction perpendicular to the central axis, with a predetermined distance from each other in the central axial direction of the cylindrical container 7 (the above-described agitator). The agitating blade 3 can be rotated by rotating the fixed shaft 2 by a motor 1 connected to the fixed shaft 2 so as to be disposed on a plane perpendicular to the central axis. . As an actual operation example, the stirrer is arranged (installed) in the vertical direction so that the raw material supply port 4 (one end) is at the top and the discharge port 6 (the other end) is at the bottom, and the stirring blade 3 is rotated. However, a mixture containing the aqueous solvent and the monomer is supplied from the raw material supply port 4 into the cylindrical container 7. The supplied mixture moves downward in the cylindrical container 7 while receiving stirring force by the rotation of each stirring blade 3, and finally a monomer emulsion is obtained from the discharge port 6. The polymerization initiator is injected from the initiator supply port 5, or as shown in FIG. 2 or 3, the polymerization initiator is injected from the polymerization initiator supply port 5 provided in the middle of the cylindrical container of the stirrer. Thus, a polymer emulsion or an emulsion in the middle of polymerization is obtained from the outlet 6. As described above, the stirrer is preferably arranged in the vertical direction with the raw material supply port 4 at the top and the discharge port 6 at the bottom, which is advantageous for preventing leakage of the mixture containing the aqueous solvent and the monomer. Therefore, the arrangement direction of the stirrer is not particularly limited as long as a measure for preventing the leakage is sufficiently performed, and can be arbitrarily set as appropriate.

In the stirrer, it is preferable that six or more stirring blades 3 are usually fixed to the fixed shaft 2. More preferably, the number is 9 or more, still more preferably 12 or more, and particularly preferably 15 or more. By providing a large number of stirring blades 3, it is possible to satisfactorily mix the aqueous solvent and the monomer and prepare the monomer emulsion. The shape of the stirring blade 3 is not limited, but may be, for example, a triangle, a quadrangle, a pentagon, a hexagon or a polygon more than that, a disk shape or a gear shape, and a rod shape. May be.
In the stirrer, the shape of the cylindrical container 7 is not particularly limited as long as it is a cylindrical shape capable of passing liquid, but a cylindrical shape (columnar shape) is preferable. In the case of a cylindrical shape, the ratio of the axial length to the diameter of the cross section perpendicular to the axial direction (inner diameter of the cylinder) “the length in the axial direction / diameter of the cross section” is appropriately within a range of 1/1 or more. What is necessary is just to set and although it does not limit, For example, 3/1 or more are preferable, More preferably, it is 6/1 or more, More preferably, it is 10/1 or more. The upper limit of the ratio is not limited, but is preferably about 100/1. More preferably, it is 50/1, and more preferably, it is 30/1.

In the preparation of a monomer emulsion using a stirrer, the particle size of the monomer fine particles can be made uniform by applying a relatively gentle stirring force in multiple stages. On the other hand, a dispersion (emulsification) machine often used conventionally has one stirring blade (one stage). Therefore, when continuously preparing a monomer emulsion, until the monomer droplets have a desired particle size. A sufficient stirring force cannot be applied, and even monomer droplets having a relatively large particle size are subjected to the polymerization reaction as they are, causing variations in the particle size of the polymer particles. Many equipment using an emulsifying and dispersing turbine has been developed, but the monomer is emulsified by a strong shearing force, so that sufficient stirring force until the monomer droplets have the desired particle size can be applied. Although it is possible, it cannot be said that it is advantageous in terms of achieving a uniform particle size.

By using the agitator, the particle size of the monomer droplets in the monomer emulsion can be made more uniform. Specifically, although depending on the kind and composition of the monomer and the polymerization reaction conditions, the coefficient of variation of the particle size can be usually about 30% or less, preferably 20% or less, more preferably 12%. Hereinafter, it can be more preferably 8% or less, particularly preferably 5% or less.

The stirrer is preferably a stirrer having the above-described configuration, but may further include a temperature adjusting device for adjusting the temperature of the stirrer. By allowing the temperature of the stirrer to be adjusted, it is possible to obtain a suitable temperature in the dispersion process, polymerization reaction, and the like inside the stirrer.
The agitator may also be provided with a heating tube for heating the reaction raw material at the raw material supply port. By heating the raw material to an appropriate temperature and supplying it to a stirrer, the compound represented by the general formula (1) can be suitably dispersed.

It is preferable that the agitator has a reaction tube installed at the discharge port. By installing the reaction tube, the polymerization solution dispersed by the stirrer can be continuously polymerized to prepare an emulsion. Since it is desirable to maintain a constant temperature (reaction temperature), the reaction tube preferably has a function as a heat exchanger. Therefore, for example, it is preferable to install in a water bath or oil bath set to a desired temperature. Moreover, you may install in the airflow maintained at desired temperature. In order to improve the heat exchange function of the reaction tube, a heat radiating plate (heat radiating fin), a heat pipe, or the like may be attached or a part of the heat pipe. As other reaction tube forms, the heat exchanger itself may be used as the reaction tube. The temperature adjusting method for the reaction tube described here may be considered as a specific method for adjusting the temperature of the agitator.

The reaction tube is preferably provided with a stirring action by setting a stirring coil in the tube. The stirring plate and / or coil may be left stationary or fixed and self-stirring may be performed by the reaction liquid flow, and operations such as rotation, vibration, and swinging may be performed using an electric motor or magnetic force. Also good.
As the reaction tube, a stainless steel cylindrical tube is preferable because it has an advantage of being easily connected to a stirrer and industrial availability. A single tube such as a square tube or an oval tube is also suitable. It is a preferable choice to ensure a heat exchange function by passing a heat medium through them. In this respect, a double tube structure or a multiple tube structure is also preferable. Further, two or more pipes may be used in parallel by branching the flow path instead of a single pipe.

FIG. 1 is an example of a possible basic form of the agitator. FIG. 4 is a photograph showing an example in which a reaction tube is attached to the stirrer of the type shown in FIG. A polymerization solution containing a monomer essentially containing the compound represented by the general formula (1) and an aqueous solvent is supplied from the raw material supply port 4. Next, the polymerization solution is stirred by the stirring blade 3 driven by the motor 1 and dispersed in contact with the plurality of stirring blades as it goes to the discharge port, and the dispersion proceeds stepwise. The initiator can be introduced from the initiator supply port 5. A reaction tube can also be installed at the discharge port 6 of the stirrer.

FIG. 2 is a preferred example of a possible basic form of the agitator. FIG. 5 is a photograph showing an example in which a reaction tube is attached to the stirrer of the type shown in FIG. In this stirrer, the initiator supply port 5 is provided at a suitable portion from the latter half of the stirring portion, that is, from the center to the last stage portion. The installation position of the initiator supply port can be determined in consideration of the reaction state and the like. This stirrer is preferable when the polymerization reaction rate is high and it is particularly necessary to pay particular attention to the removal of heat of reaction. Also in this stirrer, a reaction tube can be installed at the discharge port 6.

FIG. 3 is an important example of a possible basic form of the agitator. FIG. 7 is a photograph showing an example in which a reaction tube is attached to the stirrer of the type shown in FIG. In this stirrer, an initiator (solution) introduction pipe is attached to the first stage or the first half of the stirring part. This stirrer is a preferred configuration as a stirrer used for ordinary emulsion polymerization. In this case, since the polymerization reaction occurs simultaneously with the fine pulverization of the monomer droplets, an emulsion can be synthesized even with a raw material composition that cannot be synthesized due to, for example, intense fusion of monomer droplets in the usual emulsion synthesis method. Also in this stirrer, a reaction tube can be installed at the discharge port 6. The possible types of the stirring device are divided into FIG. 1 to FIG. 3, and as shown in FIG. 6, an initiator supply port is installed near the center and the configuration near the boundary between the types of FIG. 2 and FIG. It is also possible to do.

In the stirrer shown in FIG. 3, a part of the stirrer can be used as a reaction tube, and the length of the reaction tube can be shortened, or a form that apparently does not use the reaction tube can be adopted. FIG. 10 is a photograph showing an example of an apparatus configuration in which the stirrer of the type shown in FIG. 3 is directly set in the emulsion collection container (reservoir). In the schematic diagrams of FIGS. 1 to 3, the flow path near the discharge port is bent, but it can be used without bending the flow path near the discharge port as shown in FIG. By optimizing the reaction conditions such as the heating temperature of the reaction raw material mixture, the flow rate, the temperature of the stirrer, the volume and length of the stirrer, a part or all of the polymerization reaction of the polymer emulsion can be performed in the stirrer. It is. In this case, a part of the polymerization reaction of the polymer emulsion can be performed and a further polymerization reaction can be performed in a reaction vessel that can be installed following a stirrer, resulting in a semi-continuous polymerization method, and if all are performed, it is continuous. It becomes one mode of the polymerization method. In addition, when the heat is intensely generated during the polymerization reaction, it may be difficult to remove heat from the stirrer.However, if the reaction mixture boils due to generation of excessive reaction heat, the reaction liquid in the stirrer is discharged to the discharge port. It will be discharged | emitted, and the reaction heat generation amount (generation rate) in a stirrer will fall. Therefore, in order to exhibit such a preferable self-control characteristic for safe operation, the generation of reaction heat in the stirrer itself does not impair the safety of using the stirrer shown in FIGS. In addition, it is preferable to pay attention to the setting of heat removal and raw material supply rate so that the reaction mixture does not boil, and the safety can be further improved by installing the temperature control device in a stirrer.

When the stirrer of FIG. 3 is used, a semi-continuous polymerization method or a continuous polymerization method is used. However, since the monomer component proceeds in a micelle and / or monomer droplets, the monomer component is discharged from the stirrer. The resulting reaction mixture will be close to the final preparation polymer emulsion. On the other hand, in the simple batch method, the monomer emulsion charged and the polymer emulsion in the reaction vessel are clearly different from each other, and the polymer particles are mixed with simple monomer droplets. Due to this feature, the semi-continuous polymerization method is different from the batch synthesis method even though it is apparently a batch synthesis operation.

The emulsion having ultraviolet absorbing ability of the present invention is composed of the above-described composition, and has excellent ultraviolet absorbing ability, and can sufficiently exhibit basic performance possessed by polymer fine particles, and a polymerization step of a polymerizable ultraviolet absorbing compound. Is a method for producing an emulsion capable of sufficiently copolymerizing monomers having various characteristics, in which troubles such as formation of aggregates are suppressed.

The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to these examples. Unless otherwise specified, “part” means “part by weight” and “%” means “mass%”.

Example 1
A stirrer is equipped with a heating tube and a reaction tube for heating the reaction raw material, monomer (2EHA 54 g, CHMA 67.8 g, MMA 36 g, MAA 1 g, RUVA-93 67.8 g), water 240 g, concentrated aqueous ammonia 0.35 g, surfactant (lauryl) A slurry mixture consisting of 3.38 g of sodium sulfate was heated through a heating tube and introduced into a stirrer. At the same time, a polymerization initiator aqueous solution (1.52 g of ammonium persulfate, 30 g of water, 0.28 g of sodium lauryl sulfate) is supplied to the second liquid passing port of the stirrer, and the polymerization reaction is performed simultaneously with the fine pulverization of the monomer droplets. It was. At this time, the heating temperature of the heating tube and the reaction tube was 90 ° C. The initial reaction mixture discharged from the outlet of the reaction tube was removed, and the reaction mixture exhibiting the appearance of an emulsion was collected in a receiver.
The recovered emulsion was 379 g, and had a solid content ratio of 45.4%, a particle diameter of 65 nm (SD29%), and a weight average molecular weight of 7 million.

Example 2
A monomer (CHMA 67.8g, MAA 1g, LMA 39.8g, BMA 50.6g, RUVA-93 67.8g) was used in the same manner as in Example 1 to recover 420g of an emulsion. The solid content ratio was 44.7%, the particle diameter was 72 nm (SD27%), and the weight average molecular weight was 7,300,000.

Reference example 1
Monomers (styrene 167 g, MAA 0.83 g), water 300 g, concentrated aqueous ammonia 0.21 g, surfactant as reactive emulsifier (Aqualon BC1025 3.3 g, solid content 0.83 g), polymerization initiator aqueous solution ( Ammonium persulfate (1.5 g), water (15 g), the heating temperature of the heating tube and the reaction tube were set to 92 ° C., and operation was performed in the same manner as in Example 1 to recover 455 g of the emulsion. The solid content ratio was 31.7%, the particle diameter was 143 nm (SD 5.2%), and the weight average molecular weight was 149 k. The number average molecular weight was 51 k, and Mw / Mn was 2.9.

Example 3
Monomer (CHMA 80 g, MMA 40 g, MAA 0.5 g, Chisorb 568780 g), water 250 g, concentrated aqueous ammonia 0.1 g, surfactant as reactive emulsifier (Aqualon BC1025 28 g, solid content 7 g), polymerization initiator aqueous solution Ammonium sulfate (1.5 g), water (15 g), the heating temperature of the heating tube and the reaction tube was set to 92 ° C., and the same operation as in Example 1 was carried out to recover 401 g of the emulsion. The solid content ratio was 40.3%, the particle diameter was 68 nm (SD39%), and the weight average molecular weight was 2.2 million. The number average molecular weight was 873 and Mw / Mn was 2.5.

Example 4
A 1 L separable flask was equipped with a stirring blade, a thermometer, and a stirrer, and heated to 95 ° C. using a water bath to replace with nitrogen. A stirrer is equipped with a heating tube for heating the reaction raw material, monomer (2EHA132g, GMA1.4g, MMA68g, MAA1.8g, RUVA-93 200g), water 520g, concentrated ammonia water 0.9g, surfactant (polymer surface activity) The slurry mixture consisting of the agent DM-1N 50 g, solid content 10 g, manufactured by Nippon Shokubai Co., Ltd. was heated through a heating tube at 95 ° C. and introduced into a stirrer. At the same time, a polymerization initiator aqueous solution (ammonium persulfate 3.0 g, water 30 g) was supplied to the second liquid passing port of the stirrer, and the polymerization reaction was performed simultaneously with the fine pulverization of the monomer droplets. The reaction mixture discharged from the outlet of the stirrer was homogenized by a stirring blade in a separable flask. 986 g of emulsion was recovered. The solid content ratio was 41.5%, the particle size was 176 nm (SD 19%), and the aggregate generation ratio was 0.072%.

Example 5
The monomer was (2EHA 132 g, MMA 68 g, MAA 1.8 g, RUVA-93 200 g), water was 540 g, the surfactant was (reactive emulsifier Aqualon BC1025 32 g, solid content 8 g), and the heating temperature was 93 ° C., as in Example 5. Operated. 990 g of emulsion was recovered. The solid content ratio was 40.9%, the particle size was 172 nm (SD 7.7%), the weight average molecular weight was 44 k, and the aggregate generation ratio was 0.15%. The number average molecular weight was 22k, and Mw / Mn was 2.0.

Example 6
The monomer was (2EHA 76 g, MMA 124 g, MAA 1.8 g, RUVA-93 200 g), water was 540 g, the surfactant was (reactive emulsifier Aqualon BC1025 32 g, solid content 8 g), and the heating temperature was 92 ° C., as in Example 5. Operated. 992 g of the emulsion was recovered. The solid content ratio was 41.0%, the particle diameter was 178 nm (SD 13%), the weight average molecular weight was 66 k, and the aggregate generation ratio was 0.072%. The number average molecular weight was 29 k, and Mw / Mn was 2.3.

Reference example 2
The monomer is only 400 g of styrene, 550 g of water, no surfactant, 20 g of water and 1 g of ammonium persulfate are put in advance in a separable flask, and the heating temperature is 94-95 ° C. Was recovered. Solid content ratio 20.4%, particle size 330nm (SD39%), molecular weight distribution shows wide bimodality (multimodal), weight average molecular weight on the high molecular weight side is 1690k, number average molecular weight is 1010k, low molecular weight The weight average molecular weight on the side was 79 k, and the number average molecular weight was 31 k. As a whole, the weight average molecular weight was 742 k, the number average molecular weight was 51 k, and Mw / Mn was 14.5.

Reference example 3
A monomer (333 g of styrene, 1.67 g of MAA), 600 g of water, 0.42 g of concentrated aqueous ammonia, a surfactant (7 g of reactive emulsifier Aqualon BC1025, solid content 1.75 g), and a polymerization initiator aqueous solution (ammonium persulfate 2 0.5 g, 30 g of water), 38 g of water and 0.4 g of ammonium persulfate were charged in advance into a separable flask, and the operation was carried out in the same manner as in Example 5 at a heating temperature of 95-97 ° C. to recover 993 g of the emulsion. The solid content ratio was 33.2%, the particle diameter was 182 nm (SD 16%), and the weight average molecular weight was 133 k. The number average molecular weight was 47 k, and Mw / Mn was 2.8.

Example 7
First, 20 g of water, 0.1 g of concentrated ammonia water, and 5 g of surfactant DM-1N (solid content 1 g) were charged into the reaction flask, and the monomers (2EHA 107 g, CHMA 275 g, HEMA 6 g, LA-87 8 g, GMA 2 g), water Was 530 g, concentrated aqueous ammonia 1.33 g, the surfactant (DM-1N 30 g, solid content 6 g), the heating temperature was 70 ° C. and the same operation as in Example 5. 1009 g of the emulsion was recovered. The solid content ratio was 39.7%, the particle diameter was 200 nm (SD 7.3%), and the aggregate generation ratio was 0.10%.

Example 8
First, 20 g of water and 0.5 g of a surfactant sodium lauryl sulfate were charged into a reaction flask, monomers (CHMA 163 g, HEMA 28 g, MAA 1 g, LMA 125 g, styrene 84 g), water 550 g, concentrated ammonia water 0.5 g, and surface activity. The same procedure as in Example 5 was performed, except that the agent was 6 g of sodium lauryl sulfate and the heating temperature was 70 ° C. 1015 g of emulsion was recovered. The solid content ratio was 39.8%, the particle diameter was 72 nm (SD21%), the weight average molecular weight was 1590 k, and the aggregate generation ratio was 0.035%. The number average molecular weight was 158 k, and Mw / Mn was 10.1.

FIG. 1 is a schematic diagram showing an example of a stirrer according to the present invention. FIG. 2 is a schematic view showing an example of the stirrer of the present invention. FIG. 3 is a schematic view showing an example of the stirrer of the present invention. FIG. 4 is a photograph showing an example of an apparatus configuration in which a reaction tube is attached to the stirrer of the type shown in FIG. FIG. 5 is a photograph showing an example of an apparatus configuration in which a reaction tube is attached to the stirrer of the type shown in FIG. FIG. 6 is a photograph showing an example of a device configuration in which a reaction tube is attached to the stirrer of the type shown in FIG. 2 or FIG. 3 having an initiator supply port near the central portion of the stirring portion. FIG. 7 is a photograph showing an example of an apparatus configuration in which a reaction tube is mounted on the stirrer of the type shown in FIG. FIG. 8 is a photograph showing an example of an apparatus configuration in which a heating tube and a reaction tube for heating a reaction raw material are mounted on the stirrer of the type shown in FIG. FIG. 9 is a photograph showing an example of a device configuration in which a heating tube, a reaction tube, and an emulsion recovery container (reservoir) for heating a reaction raw material are attached to the stirrer of the type shown in FIG. An apparatus based on this configuration was used in Examples 1, 2, and 3 and Reference Example 1. FIG. 10 shows an example of an apparatus configuration in which a reaction tube is not attached apparently by attaching a heating tube for heating the reaction raw material to the stirrer of the type in FIG. 3 and allowing the polymerization reaction to proceed in the stirrer. It is a photograph. An apparatus based on this configuration was used in Examples 4, 5, 6, 7, 8, and Reference Examples 2 and 3.

Explanation of symbols

1: Motor 2: Fixed shaft 3: Stirring blade 4: Raw material supply port 5: Initiator supply port 6: Discharge port 7: Cylindrical container 8: Reaction tube 9: Triangular support 10: Reservoir connection silicone tube 11: Heating tube 12 for reaction raw material heating: emulsion recovery container (reservoir)

Claims (8)

A method for producing an emulsion comprising:
The emulsion has the following general formula (1):

(In the formula, R ¹ represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms. R ² represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 8 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. Represents at least one selected from the group consisting of a cyano group and a nitro group, and R ³ represents a linear or branched alkylene group having 1 to 12 carbon atoms or —O—R ⁴ —. R ⁴ represents a linear or branched alkylene group having 2 or 3 carbon atoms, and R ⁵ represents a hydrogen atom or a methyl group. It is prepared by polymerizing a polymerization solution containing components ,
The production method includes a polymerization solution containing a monomer component essentially containing the compound represented by the general formula (1) and an aqueous solvent, and a step of preparing an emulsion essentially containing an initiator,
A cylindrical container, a rotatable fixed shaft provided along the central axis of the cylindrical container, and a plurality of stirring blades fixed to the fixed shaft at a predetermined interval in the vertical direction. And the manufacturing method of the emulsion characterized by disperse | distributing the compound represented by this General formula (1) in an aqueous solvent using the stirrer which does not have a baffle plate. The method for producing an emulsion according to claim 1, wherein the emulsion is prepared with an emulsifier amount of 1.7% by mass or less with respect to 100% by mass of all monomer components. 3. The emulsion according to claim 1 or 2, wherein the emulsion is prepared with 25% by mass or more of the compound represented by the general formula (1) with respect to 100% by mass of all monomer components. A method for producing the emulsion as described. The emulsion production method of emulsion according to any one of claims 1-3, characterized in that the monomer component ratio of the polymerizable solution are those that will be prepared as a 40% by mass or more. The emulsion according to any one of claims 1 to 4, wherein the stirrer is provided with a raw material supply port at one end of a cylindrical container and a discharge port and an initiator supply port at the other end, respectively. Manufacturing method. The stirrer is provided with a raw material supply port at one end of a cylindrical container, a discharge port at the other end, and an initiator supply port on the discharge port side with respect to the axial center of the cylindrical container. The method for producing an emulsion according to claim 1, wherein the emulsion is a product. In the stirrer, a raw material supply port is provided at one end of the cylindrical container, a discharge port is provided at the other end, and an initiator supply port is provided on the raw material supply port side with respect to the axial center of the cylindrical container. The method for producing an emulsion according to any one of claims 1 to 4, wherein The manufacturing method according to, characterized in that said formula is also the initiator together with the compound represented by (1) polymerization solution dispersed in an aqueous solvent continuously polymerizing in the stirrer to prepare an emulsion Item 8. The method for producing an emulsion according to any one of Items 1 to 7 .

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