JP2007009025A - Emulsion having ultraviolet absorptive power - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an emulsion having excellent ultraviolet absorptive power and good coating film-forming properties. <P>SOLUTION: The polymer emulsion comprises polymer fine particles having a glass transition temperature of ≥40°C obtained by polymerizing a compound represented by formula (1) as an essential monomer component and polymer fine particles having a glass transition temperature of ≤30°C obtained by polymerizing the compound represented by formula (1) as an essential monomer component. <P>COPYRIGHT: (C)2007,JPO&INPIT

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.

The polymer emulsion is used, for example, as it is or as a main ingredient in adhesives, coating agents, water-based paints, and the like, and is further used in a wide range of applications such as cosmetic ingredients, pharmaceuticals, diagnostic agents, test agents and the like. The polymer emulsion can impart ultraviolet absorbing ability by forming polymer fine particles using an ultraviolet absorbent as a raw material component. As a result, it becomes possible to develop long-term weather resistance as a coating agent, and to protect a protected object from deterioration due to ultraviolet rays. In applications such as cosmetics and pharmaceuticals, the skin can be protected from UV damage.

  The present inventor has developed a method for synthesizing a polymer emulsion that can be used as a high-performance ultraviolet absorber (ultraviolet shielding agent) (see Patent Document 1). As a result, it is possible to practically synthesize emulsions containing fine polymer particles obtained by copolymerizing high-melting UV-absorbing monomers at a high ratio under low emulsifier use conditions. Absorbents can now be easily synthesized. The UV shielding property of the thin film formed using this polymer emulsion shows good properties depending on the type and quantity of the UV-absorbing monomer raw material used for the synthesis of the polymer fine particles. The usefulness of was confirmed.

  However, the water-based ultraviolet absorber of the invention exhibits the characteristic that the minimum film forming temperature (MFT) is higher by about 20 ° C. or more than the glass transition temperature of the polymer fine particles, as is generally seen in ordinary emulsions. It was a thing. This is a disadvantageous property for forming a coating film (coating film, coating film, coating film). In particular, when a coating film having a high glass transition temperature is required, application is impossible unless the object to be coated has heat resistance. As a method of solving the problem that the minimum film forming temperature is high, there is a case where a solution of lowering the glass transition temperature of polymer fine particles can be used. However, in general, it causes a new problem that the coat film becomes soft.

  In recent years, it has been recognized that long-wavelength ultraviolet light called UV-A causes skin aging, but has the property of transmitting through glass. Therefore, it is important to control the indoor environment of a building by applying an ultraviolet absorber to a glass plate for windows or daylighting to block long wavelength ultraviolet rays. The inventor tried to form an ultraviolet absorbing coating film having a film thickness of about 2 to 6 μm on the glass plate in consideration of this point. However, surprisingly, when the ultraviolet absorber was thinly applied, there was a problem that a good coat film might not be formed even when heated to a temperature considerably higher than the minimum film formation temperature or glass transition temperature.

  Regarding the above-mentioned problem of poor film formation characteristics, an appropriate organic solvent is mixed with a film formation aid as a normal countermeasure. As a result, the minimum film-forming temperature is lowered, and a coating film having a desired glass transition temperature is formed by volatilizing the film-forming aid after coating. Although this method is very effective, a volatile organic substance is released into the environment if the exhaust treatment after application is not properly performed.

Production method of polymer emulsion (Japanese Patent Application Laid-Open No. 2005-146150), Emulsion (Japanese Patent Application No. 2005-143308)

  The above-mentioned problem, that is, the problem to be solved, can be solved by improving the film-forming characteristics when thinly applied and by heating to a temperature around the glass transition point at the maximum so that a desired coat film is formed. The present invention has the basic performance of being excellent in ultraviolet absorbing ability, does not contain a volatile organic substance, and can easily form a desired coating film only by heating from the vicinity of the glass transition temperature to a slightly higher temperature after coating. It is intended to provide an aqueous UV absorber (emulsion).

  The inventor has intensively studied the improvement of the film forming characteristics of an aqueous UV absorber. As a result, the inventors have conceived that a polymer emulsion comprising polymer fine particles having a high glass transition temperature and polymer fine particles having a low glass transition temperature is an effective means for solving the above problems, and has reached the present invention.

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

(Wherein 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 group selected from the group consisting of nitrile group, R ³ is a linear or alkylene group having a carbon number of 1-12 with branched chain structure or -O-R ⁴ - represents a .R ⁴ Represents an alkylene group having a straight chain or branched chain structure and having 2 or 3 carbon atoms, R ⁵ represents a hydrogen atom or a methyl group.) Glass transition obtained by polymerizing a compound represented by as an essential monomer component A polymer comprising polymer fine particles having a temperature of 40 ° C. or higher and polymer fine particles having a glass transition temperature of 30 ° C. or lower obtained by polymerizing the compound represented by the general formula (1) as an essential monomer component. -Emulsion.
(2) The emulsion according to (1), wherein the ratio (mass ratio) of the polymer fine particles is 40% or more.
(3) The emulsion according to (1, 2), wherein the proportion (mass ratio) of the emulsifier is 2.5% or less.
It is about.

  The present invention is described in detail below.

  The present invention is an emulsion containing fine polymer particles obtained by polymerizing the monomer represented by the general formula (1) together with other monomers, and is characterized by containing fine polymer particles having different glass transition temperatures. To do. This characteristic realizes not only a good ultraviolet absorbing ability but also a favorable characteristic that it has a good coat film forming characteristic without containing a volatile organic substance such as a film forming aid.

  The ultraviolet absorbent (emulsion) of the present invention is characterized by containing fine polymer particles having different glass transition temperatures. As a synthesis method, polymer fine particles may be formed from two or three or more types of monomer droplets in the same reaction solution. In this case, for example, two or more cylindrical stirring devices as shown in “Production Method of Polymer Emulsion (Japanese Patent Laid-Open No. 2005-146150)” are used to generate monomer droplets with each stirring device, and suspension polymerization is performed. A method in which polymer fine particles are formed by introducing into the same aqueous polymerization medium while paying attention to the conditions can be applied.

  The present inventor further studied the emulsion synthesis method described in JP-A-2005-146150, and while supplying monomers to the agitator, at the same time, supplying a polymerization initiator to the agitator and generating monomer droplets safely and stably It was found that a polymerization reaction can be caused to occur (Japanese Patent Application No. 2005-143308). This should be a continuous polymerization method or a semi-continuous polymerization method. As an application of Japanese Patent Application Laid-Open No. 2005-146150 (Japanese Patent Application No. 2005-143308), monomers having different compositions are supplied to two or three or more stirrers, and at the same time, a polymerization initiator is supplied to the stirrer to form monomer droplets. The polymerization reaction can be caused to occur while being produced, but can be applied to the synthesis of the ultraviolet absorber of the present invention. Here, the reaction conditions for emulsion polymerization can also be used by selecting the operating conditions of the stirrer. That is, if most of the monomer is consumed by emulsion polymerization in the stirrer, polymer fine particles having different glass transition temperatures corresponding to the initially supplied monomer composition are stably formed. In particular, when the operation is performed under the condition that the monomers are uniformly mixed after they are consumed, it is equivalent to mixing two or three or more types of polymer emulsions separately prepared in advance.

  In the above method for synthesizing the ultraviolet absorbent of the present invention directly from raw materials such as monomers, water and emulsifier, the ratio of the total mass of monomers to the total mass of the raw materials is usually 30% (mass%) or more. Although it depends on the use conditions, if it is less than 20% by mass, the emulsion may not be able to exhibit the ultraviolet shielding effect sufficiently. The ratio of the total mass of monomers to the total mass of the raw material is preferably 35% by mass or more, more preferably 40% by mass or more.

  As a method for preparing the ultraviolet absorber of the present invention, it is technically easy to mix two or more types of polymer emulsions to obtain an emulsion containing polymer fine particles having different glass transition temperatures. In this case, it is possible to use a method prepared by the method disclosed in the above Japanese Patent Application Laid-Open No. 2005-146150, or the above-mentioned continuous polymerization method or semi-continuous polymerization method (Japanese Patent Application No. 2005-143308) improved. preferable. Further, an emulsion formed by phase conversion after solution polymerization can also be used.

  When an ultraviolet absorber (emulsion) is applied, it is generally preferable that the ratio (mass ratio) of the polymer fine particles is high. This is because when the proportion of the polymer fine particles is low, the amount of coating increases, which causes problems such as dripping and longer drying time. On the other hand, the proportion of polymer fine particles in both cases of directly synthesizing an ultraviolet absorber using two or more monomers or synthesizing a polymer emulsion as a raw material for preparing the ultraviolet absorber When it becomes high, it becomes difficult to synthesize. In this respect, the ratio of the polymer fine particles of the ultraviolet absorber (polymer emulsion) is limited. Usually, the ratio of the polymer fine particles of the ultraviolet absorber (polymer emulsion) is 30 to 60%, preferably 35 to 50%, more preferably 40 to 50%. Depending on the intended use of the UV absorber, it may be preferable that the proportion of polymer fine particles is higher, but it is possible to increase the proportion of polymer fine particles by a method such as concentration (evaporation of water) to 50 to 70%, for example. Is possible. In the synthesis of a practical polymer emulsion, the raw material monomer is almost completely converted into polymer fine particles. Since the amount of emulsifier used is small, the proportion (mass ratio) of the polymer fine particles described here is practically equal to the solid content (non-volatile content, also referred to as NV), and the total amount of synthetic raw materials such as water and monomers Equal to the ratio of the total mass of monomer to mass.

  When the ultraviolet absorber of the present invention is prepared by mixing two or more types of polymer emulsions, in order to satisfy the above-described ratio of polymer fine particles, at least one of the raw materials must have a ratio of polymer fine particles (mass ratio, NV) must be at least 30% by weight, usually 40% by weight or more. In this respect, the ultraviolet absorbent (emulsion) of the present invention has a glass transition temperature of preferably 40 ° C. or higher, more preferably a ratio of polymer fine particles (mass ratio, NV) of 50 ° C. or higher is 40% by mass or higher. An emulsion having a glass transition temperature of preferably 30 ° C. or lower, more preferably a glass transition temperature of 20 ° C. or lower, particularly preferably 10 ° C. or lower, and a ratio (mass ratio, NV) of 40% or higher. It is preferable to prepare by mixing. If the ratio (mass ratio, NV) of at least one polymer fine particle of the polymer emulsion used as the raw material is high, the ratio (mass ratio, NV) of the polymer fine particles of other polymer emulsions may be low depending on the mixing ratio of the raw materials. The ratio (mass ratio, NV) of the polymer fine particles as the ultraviolet absorber (polymer emulsion) can satisfy the above-described numerical values. Therefore, the ultraviolet absorbent (emulsion) of the present invention is characterized in that the ratio (mass ratio, NV) of polymer fine particles having a glass transition temperature of preferably 40 ° C. or higher, more preferably 50 ° C. or higher is 40% or higher. The emulsion may be prepared by mixing an emulsion containing fine polymer particles having a glass transition temperature of preferably 30 ° C. or lower, more preferably a glass transition temperature of 20 ° C. or lower, particularly preferably 10 ° C. or lower. Alternatively, an emulsion characterized by containing fine polymer particles having a glass transition temperature of preferably 40 ° C. or higher, more preferably 50 ° C. or higher, and a glass transition temperature of preferably 30 ° C. or lower, more preferably 20 ° C. or lower, particularly preferably May be a mixture of emulsions characterized in that the proportion (mass ratio, NV) of polymer fine particles of 10 ° C. or less is 40% or more.

  The glass transition temperature used in the above description or the following description and description can be an actual measured value of the glass transition temperature of the polymer fine particles in the raw material. However, in terms of practical simplicity, it is a preferable choice to use a calculated value calculated using the Fox equation based on the monomer composition used in the synthesis of the raw material emulsion.

  In order to impart high ultraviolet absorbing ability, any of the two or three or more kinds of polymer fine particles present in the ultraviolet absorber (emulsion) is represented by the following general formula (1);

(Wherein 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 group selected from the group consisting of nitrile group, R ³ is a linear or alkylene group having a carbon number of 1-12 with branched chain structure or -O-R ⁴ - represents a .R ⁴ Represents an alkylene group having a straight chain or branched chain structure and having 2 or 3 carbon atoms, R ⁵ represents a hydrogen atom or a methyl group, and the branched chain is a chain having a straight carbon-carbon bond. It may preferably be formed by polymerizing a compound represented by (2) which is branched and has a branched chain structure as an essential monomer component. However, depending on the required level of ultraviolet absorbing ability, at least one kind of polymer fine particles can be formed by polymerizing a compound represented by the general formula (1) as an essential monomer component. In this case, the other types of polymer fine particles may be selected from monomer raw materials that do not contain or contain a small amount of the compound represented by the general formula (1).

  The ultraviolet absorbing monomer represented by the general formula (1) can be selected depending on other monomer components. Accordingly, different raw materials may be used for the synthesis of the polymer fine particles to be mixed. Two or more kinds of ultraviolet absorbing monomers may be mixed in the same ratio or different ratios and used for synthesis.

  The ratio of the specific compound represented by the general formula (1), that is, the ratio to the total mass of monomers to be copolymerized (copolymerization rate) is preferably 25% by mass or more, more preferably 35% by mass or more. More preferably, it is 45 mass%. In particular, when a thin film is used, it can be 50% by mass or more, 60% by mass or more as described in Examples. The ratio shown here is preferably applied to the total amount of the compound represented by formula (1) when two or more compounds are used. In addition, two types or three or more types of polymer fine particles present in the ultraviolet absorber are synthesized by copolymerizing the compound represented by the general formula (1) at the ratio (copolymerization rate) shown here. It is preferable that However, if necessary, at least one of two or more types of polymer fine particles present in the ultraviolet absorber should satisfy the above ratio (copolymerization rate), and other types of polymer fine particles to be coexisted are generally It is also possible to polymerize a monomer that does not contain the ultraviolet absorbing monomer represented by the formula (1) or that contains a small amount. As a result, it is possible to prepare an ultraviolet absorber (emulsion) that exhibits good characteristics such as glass transition temperature and film forming characteristics.

  The specific benzotriazole compound represented by the general formula (1) is not limited. For example, 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) acryloyl (Luoxyethoxy) -3'-tert-butylphenyl] -5-tert-butyl-2H-benzotriazole, 2- [2'-hydroxy-5 '-(methacryloyloxyethyl) phenyl] -2H-benzotriazole ( Preferred examples include UV-absorbing monomers manufactured by Otsuka Chemical Co., Ltd., product name RUVA-93, hereinafter referred to as RUVA-93, and 100 ° C. in the calculation of the glass transition temperature according to the Fox formula. 2- [2'-hydroxy-5 '-(methacryloyloxyethyl) phenyl] -2H-benzotriazole (RUVA-93) is more preferable. These may be used alone or in combination of two or more.

  The monomer other than the general formula (1) used for the synthesis of the polymer emulsion includes (i) a compound having an ultraviolet absorption effect other than the general formula (1), and (ii) a property of capturing or erasing radicals generated by ultraviolet irradiation. It is preferable that it is 1 type, or 2 or more types of the compound which has (it is hereafter called the monomer which has an ultraviolet stable group), and (iii) other polymerizable monomers.

  The compound (i) having an ultraviolet absorption effect is represented by 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 (1) is a linear or branched chain alkylene group having 1 to 12 carbon atoms. 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 limited. For example, 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 And) acryloyloxy] butoxybenzophenone. These may be used alone or in combination of two or more.

  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 (1). R ⁹ represents a direct bond, —O (CH ₂ CH ₂ ) _n — or —OCH ₂ CH (OH) CH ₂ —). N is an integer of 1 to 5. R ^{10 to} R ¹⁷ are the same or different and are selected from the group consisting of a hydrogen atom, an alkoxy group having 1 to 10 carbon atoms, an alkenyl group, and an alkyl group. The triazine compound represented by the above group is preferred.

  The triazine compound represented by the general formula (3) is not limited. For example, 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- Preferred examples include [2-hydroxy-4- (2-acryloyloxyethoxy)]-s-triazine. These may be used alone or in combination of two or more, or may be used in combination with one or more benzophenone compounds represented by the general formula (2).

  Although it does not 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) or (5) is mentioned preferably.

(In the general formula (4), R ¹⁸ represents a hydrogen atom or a cyano group, R ¹⁹ and R ²⁰ are the same or different and represent a hydrogen atom or a methyl group, and R ²¹ represents a hydrogen atom or a hydrocarbon group. R ²² represents an oxygen atom or an imino group.)

(However, in the general formula (5), R ^18, R ^19, R ²⁰ and R ²² are as defined R ^18, R ^19, R ²⁰ and R ²² in the general formula (4), 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 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 Preferred is -crotonoylamino-2,2,6,6-tetramethylpiperidine. These may be used alone or in combination of two or more.

  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 Preferable examples include methylpiperidine. These may be used alone or in combination of two or more, or may be used in combination with a monomer having one or more kinds of ultraviolet-stable groups represented by the general formula (4).

The (iii) other polymerizable monomer may be any monomer that can be copolymerized with the monomer of the general formula (1), but one or more of the following monomers are preferable. Examples of such a monomer include monomers having a carboxyl group such as (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid, and crotonic acid. The metal salts of monomers having a carboxyl group, for example, Na salt, K salt, NH ₄ salt, Mg salt, Ca salt, Sr salt, Zn salt, Zr salts, also preferably including Al salts, specifically, ( (Meta) sodium acrylate, potassium (meth) acrylate, ammonium (meth) acrylate, magnesium (meth) acrylate, calcium (meth) acrylate, strontium (meth) acrylate, zinc (meth) acrylate, (meta ) Zirconium acrylate, aluminum (meth) acrylate, sodium itaconate, potassium itaconate, ammonium itaconate, magnesium itaconate, calcium itaconate, strontium itaconate, zinc itaconate, zirconium itaconate, aluminum itaconate, maleic acid Sodium, potassium maleate , Ammonium maleate, magnesium maleate, calcium maleate, strontium maleate, zinc maleate, zirconium maleate, aluminum maleate, sodium fumarate, potassium fumarate, ammonium fumarate, magnesium fumarate, calcium fumarate, fumarate Strontium acid, zinc fumarate, zirconium fumarate and aluminum fumarate, sodium crotonic acid, potassium crotonic acid, ammonium crotonic acid, magnesium crotonic acid, calcium crotonic acid, strontium crotonic acid, zinc crotonic acid, zirconium crotonic acid and aluminum crotonic acid Etc. can be exemplified.

As the above (iii) other polymerizable monomer, in addition to the monomer having a carboxyl group, one or more of the following monomers are preferable. Examples of such monomers include acidic phosphate ester monomers such as 2- (meth) acryloyloxyethyl acid phosphate; 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and hydroxyl-terminated flexibility ( Monomers having groups having active hydrogen such as (meth) acrylate (for example, product name: Plaxel FM, manufactured by Daicel Chemical Industries, Ltd.); (meth) acrylamide, N, N-dimethylaminomethyl (meth) acrylate, imide ( Nitrogen-containing monomers such as meth) acrylate and N-methylol (meth) acrylamide; Monomers having two polymerizable double bonds such as ethylene glycol di (meth) acrylate; Halogen-containing monomers such as vinyl chloride; Styrene and α- Fragrance such as methylstyrene Group monomer; vinyl ether; methyl 3-methoxyacrylate (CH ₃ O—CH═CHCOOCH ₃ ); the following general formula (6)

In the formula, R ²⁵ represents a hydrogen atom or a methyl group. R ²⁶ represents a hydrocarbon group having 1 or more carbon atoms). The substituent represented by R ²⁶ in the general formula (6) (hydrocarbon group having 1 or more carbon atoms) is not particularly limited, and for example, the substituents exemplified below are preferable.

  Cyclopentyl group, cyclohexyl group, methylcyclohexyl group, cyclooctyl group, cyclododecyl group and other alicyclic hydrocarbon groups having 4 or more carbon atoms; methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, Straight chain having 4 or more carbon atoms such as sec-butyl group, tert-butyl group, 2-ethylhexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, pentadecyl group, hexadecyl group, octadecyl group A branched or branched alkyl group; a polycyclic hydrocarbon group having 4 or more carbon atoms such as a bornyl group and an isobornyl group; a benzyl group, a glycidyl group, a tetrahydrofurfuryl group, a furfuryl group, a 2-hydroxyethyl group, 2- Phenoxyethyl group, 2- (acetoacetoxy) ethyl group, N, -Aromatic rings such as dimethylaminoethyl group, N, N-diethylaminoethyl group, 2-hydroxypropyl group, 3-hydroxypropyl group, 2-hydroxybutyl group, 4-hydroxybutyl group, oxygen atom, nitrogen atom, sulfur A hydrocarbon group having a partial structure such as an atom or a phosphorus atom; a hydrocarbon group having a partial structure such as a trifluoroethyl group, a tetrafluoropropyl group, an octafluoropentyl group or a heptadodecafluorodecyl group is preferred.

  Although it does not limit as a monomer shown by the said General formula (6), For example, 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) (Meth) acrylic acid (lower, intermediate, acrylate, etc.) such as acrylate, isodecyl (meth) acrylate, dodecyl (meth) acrylate, pentadecyl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate and isostearyl (meth) acrylate Higher) alkyl esters, benzyl (meth) acrylate, dicyclopentyl (meth) acrylate, bornyl (meth) acrylate, isobornyl (meth) acrylate, cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, methylcyclohexyl (meth) acrylate, Cyclooctyl (meth) acrylate, cyclododecyl (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 hydroxypivalic acid ester (meth) Acrylate, pentaerythritol tri (meth) acrylate, 2- (meth) acryloyloxypropyl hydrogen phthalate, trimethylolpropane ethoxytri (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 hepta dodecafluoro-decyl (meth) acrylate are preferably mentioned. Among them, 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, dodecyl (meth) acrylate, glycidyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, N, N -More preferred are dimethylaminoethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate and trimethylolpropane (meth) acrylate. These may be used alone or in combination of two or more.

  Since the ultraviolet absorbing monomer represented by the general formula (1) is used in a large amount, it is an important factor when determining the glass transition temperature of the polymer fine particles. However, the selection range is narrow in that the glass transition temperature of the polymer fine particles is determined. On the other hand, as the monomer other than the monomer represented by the general formula (1), the monomer represented by the general formula (6) is generally used in a large amount as a total amount, and the selection range is wide. In this respect, the selection of the monomer represented by the general formula (6) is important in determining the glass transition temperature of the polymer fine particles.

  The fine polymer particles present in the emulsion used in the present invention are roughly classified into those having a high glass transition temperature and those having a low glass transition temperature. When the glass transition temperature of the polymer fine particles is high, the glass transition temperature is preferably 40 ° C. or higher, and more preferably the glass transition temperature is 50 ° C. or higher. The glass transition temperature of the polymer fine particles is preferably low, and the glass transition temperature is preferably 30 ° C. or lower, more preferably 20 ° C. or lower. More preferably, the glass transition temperature is 10 ° C. or lower.

  The ultraviolet absorbing emulsion is often used for the purpose of finally forming a coating film. Therefore, considering the use state, it may be considered that the glass transition temperature is high or low with reference to the required glass transition temperature of the coating film (hereinafter referred to as the required glass transition temperature). In this case, the high glass transition temperature of the polymer fine particles is preferably higher by 10 ° C. or more, more preferably higher by 20 ° C. or more than the required glass transition temperature. Moreover, it is preferable that it is 10 degreeC or more lower than the request | required glass transition temperature that a polymer fine particle has a low glass transition temperature, and it is more preferable that it is 20 degreeC or more lower.

  Since it is generally preferable that the emulsion used as the ultraviolet absorber has a low emulsifier content, those synthesized by the method previously filed by the present inventors (Japanese Patent Application Laid-Open No. 2005-146150, Japanese Patent Application No. 2005-143308) are preferred. In general, it is recommended that the amount of emulsifier is 2.5% by mass or less, preferably 1.7% by mass or less based on the total amount of monomers. By setting the amount of the emulsifier within this range, the characteristics of the polymer fine particles are easily developed. In particular, since the synthesis method in which the synthesis method of JP-A-2005-146150 is semi-continuous or continuous is easy to reduce the amount of emulsifier, the amount of emulsifier used is preferably 0.1 to 2.5% by mass, more preferably Is 0.1 to 1.7% by mass. The amount of emulsifier used is generally applicable to the synthesis of a polymer emulsion having a solid content ratio of 40% or more. Depending on the monomer composition and solid content ratio, the amount of emulsifier used can be 0.1 to 1.0% by mass, and more preferably 0.1 to 0.5% by mass. When a reactive emulsifier is used as the emulsifier and the characteristics are positively used as a constituent residue of the polymer, the amount used can be exceeded.

  As the emulsifier, for example, an anionic surfactant, a nonionic surfactant, a cationic surfactant, an amphoteric surfactant, a polymer surfactant, a reactive surfactant and the like can be used. An emulsifier may be used independently or may use 2 or more types together.

  Examples of the anionic surfactant include alkyl sulfate salts such as sodium dodecyl sulfate (sodium lauryl sulfate) and ammonium dodecyl sulfate (ammonium lauryl sulfate); sodium dodecylbenzenesulfonate, ammonium dodecylbenzenesulfonate, sodium dodecylnaphthalenesulfonate Polyoxyethylene alkyl sulfonates (commercially available products, for example, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., product name: Hightenol 18E); polyoxyethylene alkyl aryl sulfonates (commercially available) In the product, for example, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., product name: Hytenol N-08, etc.); dialkylsulfosuccinate; arylsulfonic acid formalin condensate; ammonium dodecylate, Suitable are fatty acid salts such as sodium allate, potassium oleate, castor oil carikenken, and the like.

  Nonionic surfactants include, for example, polyoxyethylene alkyl ether (commercially available product, manufactured by Sanyo Chemical Industries, Ltd., product name: NAROACTY N-200, etc.); polyoxyethylene alkyl aryl ether (commercially available product) For example, Sanyo Kasei Kogyo Co., Ltd., product name: Nonipol-200, etc.); polyethylene glycol and polypropylene glycol condensates; sorbitan fatty acid ester; polyoxyethylene sorbitan fatty acid ester; fatty acid monoglyceride; polyamide; ethylene oxide and fat A condensed product of a group amine;

  Examples of the cationic surfactant include salts of alkylamines such as dodecyl ammonium chloride, coconut amine acetate and stearyl amine acetate, and quaternary ammonium salts such as lauryl trimethyl ammonium chloride, stearyl trimethyl ammonium chloride and cetyl trimethyl ammonium chloride. Etc.

  Examples of amphoteric surfactants include alkylbetaines such as lauryl betaine, stearyl betaine, lauryl dimethylamine oxide, and alkylamine oxide type emulsifier 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. And a copolymer having one or more polymerizable monomers as a copolymerization component.

  Examples of the reactive surfactant include polyoxyethylene alkylpropenyl phenyl ethers (for example, Aqualon RNs Patent 2651736 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and sulfates thereof having various molecular weights (different number of moles of ethylene oxide added). (For example, Aqualon HS manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., Aqualon BCs, Patent 2652459) and polyoxyethylene alkyl ether sulfate salts introduced with allyl (oxy) groups (for example, Aqualon KH manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) Patent No. 2,596,441), polyethylene glycol mono (meth) acrylate, polyoxyethylene alkylphenol ether (meth) acrylic acid ester, ammonium 2- (meth) acryloyloxyethyl sulfonate, polyoxyethylene glycol Such as mono-maleic acid ester and a derivative thereof and polyoxyalkylene alkyl ether phosphate ester Lumpur thereof.

  The mixing ratio (mass ratio) of the polymer fine particles having a high glass transition temperature and the polymer fine particles having a low glass transition temperature is 15 when the diameter of the fine particles is the same, assuming that one fine particle is surrounded by the other fine particles. : 1-1: 15 is considered to be the maximum range, but considering that each fine particle can be continuously contacted to some extent, approximately 4: 1 to 1: 4 is considered to be a practical range, and three-dimensionally continuously. Considering that contact is possible, it is preferable to select in a range of about 3: 1 to 1: 3. Experimentally, when the ratio was outside the range of 3: 1 to 1: 3, the characteristics of the polymer fine particles having a large mixing ratio became conspicuous, and the advantage of the film forming characteristics as an ultraviolet absorber tended to decrease. Since the present invention utilizes the characteristics of both particles and finally forms a uniform coat film, it is particularly preferable to mix in the range of 2: 1 to 1: 2. Most preferably, mixing at 1: 1 is considered, but considering the difference in average particle diameter and the measurement error at the time of blending, 1.3: 1 to 1: 1.3 is considered the most preferable mixing ratio for practical use. It is done. Technically, the composition of the monomer used as the raw material for the polymer fine particles can be changed as necessary. Therefore, when used as a coating agent, the mixing ratio is 1: 1 in principle for the purpose of fine-tuning the coating film forming characteristics. It is technically preferable to set the range of 1.5: 1 to 1: 1.5 or at most 2: 1 to 1: 2. Even when the diameters of the fine particles are not equivalent, the mixing ratio (mass ratio) may be applied. If one of the mixing ratios increases, the feature of containing two or three or more different kinds of polymer fine particles is reduced, so that the above 15: 1 to 1:15 are considered to be a reasonable maximum range. However, a slightly wider range such as 5: 1 to 1: 5, a more preferable range of 3: 1 to 1: 3, and a more preferable range of 2: 1 to 1: 2 may be used.

  The ultraviolet absorbent according to the present invention can be applied to a molded article or product made of a synthetic resin having a bar shape, a plate shape, a cylindrical shape, a lump shape, or a composite shape thereof by a method such as dipping, brushing or spraying. Moreover, it can apply | coat to materials and articles | goods, such as products, such as cloth, a woven fabric, a fiber, leather, a blade | wing, woodwork products, paper products, and a plant. You may apply | coat to a glass plate and a glass block material. Moisture evaporates by drying after coating, and a coat film (hereinafter referred to as a primary coat film) having an ultraviolet shielding ability is formed. In the description of the present invention, the term “primary coat film” refers to a polymer film in which an ultraviolet absorber contains different polymer fine particles. Therefore, a coat film (primary coat film) formed by adhering different polymer fine particles is a homogeneous polymer. This is because the coat film is clearly different from the coat film formed by adhering the fine particles.

  In order to clearly distinguish that the primary coating film is different from a dry product formed when a normal emulsion is applied at a glass transition temperature or lower, the characteristics were examined by the evaluation method of the reference example. In the evaluation method of the reference example, the state of the coat film or the dried product is identified by the electric resistance and the stability in water.

  First, the measurement method used will be described. The fine polymer particles have a charge derived from a surfactant, a raw material monomer, and a polymerization initiator on the surface. The charge derived from the monomer of the raw material here includes not only the original raw material but also the charge of the ionic impurities in the raw material and the charge of the monomer decomposition product that may be generated during the polymerization reaction. It does not matter. The primary coat film formed by applying the emulsion with these charges exhibits conductivity according to its structure. It is considered that as the primary coat film is homogenized, the voids between the polymer particles disappear, and the charges existing on the surface of the polymer particles are dispersed in the coat film to reduce the conductivity and increase the electric resistance. When the purpose is not to form a conductive coating film as in the present invention, the type and quantity of raw materials related to conductivity such as a surfactant, an ion-dissociable monomer in the raw material, and an ionic polymerization initiator are the same. If so, an increase in the electrical resistance of the coating film indicates an increase in the homogeneity of the coating film. Therefore, it is considered that the electrical resistance and water resistance of the primary coat film formed by aggregation and fusion of polymer fine particles can be used as an index for evaluating the characteristics of the primary coat film. The validity of this idea could be confirmed by the evaluation results of the film formation characteristics for samples T0 to T50 in Table 1. T0 gives a smooth coat film with high homogeneity at room temperature (23 ° C.), but the homogeneity of the coat film decreased as the glass transition temperature increased with T10 and T20. At the same time, the electrical resistance and the water resistance of the coating film decreased. Therefore, by comparing with the measurement results of the samples T0 to T50, the primary coating film formed from the polymer fine particles of the same system can be quantitatively evaluated.

  Using this evaluation method, the primary coat film formed by the ultraviolet absorbent according to the present invention was evaluated. The measured examples are shown in Table 1. From the result that T30 having a glass transition temperature of 30 ° C. has low electric resistance and no water resistance, it can be determined that a dry product is formed by coating at room temperature. On the other hand, the UV absorber 2 and UV absorber 3 having a calculated glass transition temperature of around 30 ° C. were comparable to T20 and T30 in terms of electrical resistance, but showed considerable water resistance. Converted to a glass transition temperature, it can be determined to be equivalent to 20 ° C., and it was confirmed that a primary coating film was formed. Furthermore, in the case of the ultraviolet absorber 1 having a calculated glass transition temperature of 35 ° C., a good primary coating film having a considerable transparency was formed, and when converted to the glass transition temperature, it could be determined to be equivalent to 10 ° C. Therefore, it was recognized that the ultraviolet absorber of the present invention has utility and inventive step in comparison with the ultraviolet absorber composed of one kind of polymer fine particles.

  The primary coating film formed by the ultraviolet absorbent according to the present invention may be a final coating film as long as it satisfies the required specifications in terms of transparency and mechanical strength. Since the primary coat film or the product on which the primary coat film is formed can be provided with functions that cannot be easily realized with conventional ultraviolet absorbers such as design and decoration, they will be separately described later. A general coat film equivalent to a coat film obtained when a conventional ultraviolet absorber is applied is formed by heat treatment of the primary coat film.

  The coating amount of the ultraviolet absorber of the present invention is generally in the range of 0.3 to 10 μm as the primary coating film or the coating film, and is used in the range of 0.3 to 100 μm depending on the purpose. May be. In normal use, the range of 0.5 to 10 μm is appropriate, and the range of 1 to 6 μm is preferable in view of the balance between the drying property during coating and the ultraviolet shielding ability. When forming a transparent ultraviolet shielding coating film, the range of 1 to 4 μm is more preferable. In the case of using an opaque primary coat film, it is also preferably in the range of 3 to 10 μm.

  When a general coat film is formed, it is preferable to heat-treat the primary coat film up to a calculated glass transition temperature or a high temperature of 10 ° C. If there is no problem in the heat resistance of the article to be coated such as a synthetic resin product, the primary coating film can be heat-treated to the calculated glass transition temperature, its 20 ° C. or higher temperature. This heat treatment is preferable as a general coating film because it is homogeneous in appearance, increased in transparency, and increased in mechanical strength. When the synthetic resin product exhibits thermoplasticity, the heat treatment temperature of the primary coating film is preferably low. Synthetic resin products exhibiting general thermoplasticity often have usable temperatures of around 80 to 120 ° C. In this respect, the minimum film formation temperature is preferably 120 ° C. or less at the highest, and the minimum film formation temperature is more preferably 80 ° C. or less as a general-purpose coating agent. The ultraviolet absorber of the present invention is preferable because it has a characteristic that the minimum film-forming temperature can be increased from the same as the calculated glass transition temperature to about 10 ° C. The calculated glass transition temperature here means the glass transition temperature calculated corresponding to the raw material monomer composition of the entire polymer fine particle mixture. In the case of a simple polymer emulsion, the minimum film formation temperature is often about 30 ° C. higher than the glass transition temperature. Therefore, the glass transition temperature of the polymer fine particles of a simple polymer emulsion must be 30 ° C. or more lower than the usable temperature of the article to be coated, and depending on the film forming characteristics, it has been necessary to lower it by 40 ° C. or more. As described above, when the glass transition temperature of the polymer fine particles, that is, the coating film is low, the coating film becomes soft, so that there is a concern that the coating film and other articles are bonded to each other. In the ultraviolet absorbent according to the present invention, the heat treatment temperature of the primary coating film can be made equal to the usable temperature of the article to be coated, and this temperature can be made near the calculated glass transition temperature. As a result, it is possible to form a coating film having a glass transition temperature that is usually 20 to 30 ° C., and in some cases 40 ° C. or more higher than that of a coating film formed from a simple polymer emulsion.

  The primary coating film formed by the ultraviolet absorbent according to the present invention can be provided with functions that cannot be easily realized by conventional ultraviolet absorbent coating films such as design and decoration. That is, the ultraviolet absorbent of the present invention has two or more types of polymer fine particles having a high glass transition temperature and polymer fine particles having a low glass transition temperature, but these characteristics are different in characteristics such as optical characteristics. Therefore, by adjusting the characteristics of the polymer fine particles, it is possible to impart a decorative property that is not found in a conventional ultraviolet shielding coating film using an ultraviolet absorber.

  The primary coating film can be white, translucent or transparent by selecting the composition and characteristics of the polymer fine particles. Therefore, for example, by applying the ultraviolet absorbent of the present invention to a synthetic resin plate such as a glass plate, an acrylic plate, a vinyl chloride plate, or a polystyrene plate as a paint or spray, the ultraviolet shielding ability, visible light scattering effect, An infrared scattering effect can be imparted and a blinding effect can be imparted.

  The primary coating film can be converted into a homogeneous or apparently uniform coating film by heat treatment, and can be made transparent. As the utilization of the characteristics, the transparency can be increased by heat-treating a specific portion, and a translucent or further transparent portion can be formed into a desired shape. Therefore, by controlling the heating area and temperature and time, for example, people, animals, plants, fungi, microorganisms, buildings, natural objects, landscapes, patterns, etc. can be formed on coated materials such as glass plates and synthetic resin plates. , It can also provide design, decoration, and artistic properties. In this case, since it is considered that light and dark due to differences in transparency and light scattering are likely to be formed, etching glass-like or ink-jet style designs and paintings are considered to be preferred usage.

  As a heat source for the heat treatment, warm air, hot air, or infrared rays (heating furnace) may be used when heating a wide area. When a design or painting is formed on a glass plate or a synthetic resin plate, warm air, hot air, or infrared rays may be used. It is also preferable to draw by heating with a laser or an infrared beam, or simply draw sunlight as a heat source by collecting sunlight with a lens or a reflecting mirror. In any of these cases, a desired design or painting can be formed by using a stencil or the like together. The drawing method shown here can be applied not only to a glass plate or a synthetic resin plate alone, but also to a glass plate or a synthetic resin plate already used as a building material or a decorative material.

  The UV absorber of the present invention can be applied not only to a glass plate or a synthetic resin plate alone as a paint or spray, but also to structures, buildings, articles such as glass windows and mirrors that have already been used. Can also be applied. As a result, not only can an existing glass window be provided with an ultraviolet shielding ability, but also a mural, a design as a painting, a decorative property and an artistic property can be imparted. In this case, it is considered that it is easy to form light and darkness due to transparency in the glass window. Furthermore, if the ultraviolet absorber of the present invention is used by mixing a dye, the fading of the dye can be reduced and used as a colored coating agent. Therefore, for example, it is considered that it is easy not only to impart ultraviolet shielding ability to glass windows and mirrors, but also to color them and to form designs and paintings.

  The emulsion having ultraviolet absorbing ability of the present invention is characterized by the presence of polymer fine particles having different glass transition temperatures. As a result, the formation characteristics of the coated film are good, and not only an apparently uniform coated film can be obtained by heating the protected article to near the glass transition temperature, but the protected article must not be heated to the glass transition temperature. Is also characterized in that a white or transparent coat film (primary coat film) can be obtained. Further, a white or low-coating coating film (primary coating film) can provide a visible light scattering effect and an infrared scattering effect, and can impart a blinding effect. In this case, since it can be converted into a transparent or highly transparent coating film by heating, not only the coating material can be provided with an ultraviolet shielding ability, but also a design and a painting can be formed, and design and decoration can be imparted.

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. Synthesis Examples 1 to 7 are examples in which 1 kg of emulsions each containing 40% of polymer fine particles (mass ratio) that can be used for the preparation of the ultraviolet absorber of the present invention were synthesized. The emulsion that can be used in the above is not limited to synthesis examples.
Synthesis example 1
An apparatus described in Patent Document 1 (Japanese Patent Laid-Open No. 2005-146150) improved so that a polymerization initiator can be simultaneously supplied to a cylindrical stirring apparatus was used. The temperature of the water bath used to heat the synthesizer was adjusted to 89-92 ° C. An aqueous solution in which 3 g of Aqualon BC1025 (Daiichi Kogyo Seiyaku Co., Ltd.) and 15 g of water were mixed was passed through to wet the wall surface of the synthesizer. Immediately thereafter, a monomer mixture containing 175 g of 2-ethylhexyl acrylate (hereinafter abbreviated as 2EHA), 25 g of methyl methacrylate (hereinafter abbreviated as MMA) and 200 g of RUVA-93, 33 g of reactive emulsifier Aqualon BC1025, methacrylic acid ( (Hereinafter abbreviated as MAA) 1.8 g, water 530 g, and an aqueous solution prepared by mixing 0.9 g of commercially available concentrated aqueous ammonia, together with an aqueous solution prepared through a heating tube, were supplied to a cylindrical stirring device. At the same time, an emulsion (Examples and etc.) was prepared under a synthesis condition close to a continuous synthesis method in which an aqueous solution obtained by dissolving 3.0 g of ammonium persulfate in 30 g of water as a polymerization initiator was supplied to cause a polymerization reaction in a cylindrical stirring apparatus. In the reference example, it was abbreviated as T0). The polymer fine particles had an average particle diameter of 138 nm and a weight average molecular weight of 40.7 k. Film formation characteristics were evaluated using the method described in the Reference Example. The evaluation results are shown in Table 1.
Synthesis example 2
Emulsion (abbreviated as T10 in Examples and Reference Examples) using a monomer mixture containing 110 g of 2EHA, 50 g of butyl acrylate (abbreviated as BA), 40 g of MMA, and 200 g of RUVA-93 by the same synthetic operation as in Synthesis Example 1. Was prepared. The average particle diameter of the polymer fine particles was 162 nm, and the weight average molecular weight was 43.1 k. Film formation characteristics were evaluated using the method described in the Reference Example. The evaluation results are shown in Table 1.
Synthesis example 3
An emulsion (Example) using a monomer mixture containing 1 g of Aqualon BC1025, 132 g of 2EHA, 68 g of MMA, and 200 g of RUVA-93 in an aqueous solution that first wets the wall of the synthesizer by the same synthesis operation as in Synthesis Example 1. And abbreviated as T20 in Reference Examples). The polymer fine particles had an average particle diameter of 171 nm and a weight average molecular weight of 49.8 k. Film formation characteristics were evaluated using the method described in the Reference Example. The evaluation results are shown in Table 1.
Synthesis example 4
Emulsion using a monomer mixture containing 1 g of Aqualon BC1025 in an aqueous solution that initially wets the wall of the synthesizer by the same synthetic operation as in Synthesis Example 1; 112 g of 2EHA; 88 g of MMA; and 200 g of RUVA-93 In the examples and reference examples, T30 was abbreviated). The polymer fine particles had an average particle size of 194 nm and a weight average molecular weight of 57.0 k. Film formation characteristics were evaluated using the method described in the Reference Example. The evaluation results are shown in Table 1.
Synthesis example 5
Emulsion using a monomer mixture containing 1 g of Aqualon BC1025 in an aqueous solution that initially wets the wall of the synthesizer by the same synthetic operation as in Synthesis Example 1; 93 g of 2EHA, 107 g of MMA, and 200 g of RUVA-93 In the examples and reference examples, T40 was abbreviated). The average particle diameter of the polymer fine particles was 183 nm, and the weight average molecular weight was 69.5 k. Film formation characteristics were evaluated using the method described in the Reference Example. The evaluation results are shown in Table 1.
Synthesis Example 6
First, the wall of the synthesizer is wetted by the same synthetic operation as in Synthesis Example 1, and water is used as an emulsion (76% 2EHA, 124 g of MMA, and 200 g of RUVA-93). (Abbreviated)) was prepared. The average particle diameter of the polymer fine particles was 178 nm, and the weight average molecular weight was 66.4 k. Film formation characteristics were evaluated using the method described in the Reference Example. The evaluation results are shown in Table 1.
Synthesis example 7
It is water that first wets the wall of the synthesizer by the same synthesis operation as in Synthesis Example 1, 90 g of cyclohexyl methacrylate (abbreviated as CHMA), 50 g of butyl methacrylate (abbreviated as BMA), 60 g of styrene, and RUVA-93. An emulsion (abbreviated as T80 in Examples and Reference Examples) was prepared using a monomer mixture containing 200 g. The average particle diameter of the polymer fine particles was 253 nm, and the weight average molecular weight was 473 k.
Example 1
An ultraviolet absorber 1 was prepared by mixing 2 parts of the T80 emulsion and 2 parts of the T0 emulsion. A bar coater (No. 6) was used to apply to a slide glass (length 76 mm, width 26 mm, plate thickness 1 mm) to form a primary coating film having a thickness of 3 μm. A portion of the slide glass was heated on a hot plate until clearing occurred. This state is shown in FIG. The UV transmittance of the primary coating film and the transparent coating film was examined, and the results are shown in FIG. Further, the primary coating film was evaluated by the method described in the reference example. The evaluation results are shown in Table 1.
Example 2
An ultraviolet absorber 2 was prepared by mixing 2 parts of the T50 emulsion and 2 parts of the T10 emulsion. The primary coat film was evaluated by the method described in Reference Example. The evaluation results are shown in Table 1.
Example 3
An ultraviolet absorber 3 was prepared by mixing 2 parts of the T50 emulsion and 1 part of the T0 emulsion. A bar coater (No. 6) was used to apply to a slide glass (length 76 mm, width 26 mm, plate thickness 1 mm) to form a primary coating film having a thickness of 3 μm. A portion of the slide glass was heated on a hot plate until clearing occurred. In addition, the other part of the primary coating film was heated so that the degree of heating was weakened in the center direction, but the degree of transmittance was observed corresponding to the strength of heating. This state is shown in FIG. The ultraviolet transmittance of the primary coat film and the transparent coat film was examined, and the results are shown in FIG. Further, the primary coating film was evaluated by the method described in the reference example. The evaluation results are shown in Table 1.

Example 4
The ultraviolet absorbent 3 prepared in Example 3 was applied to one side of a glass plate (length 150 mm, width 100 mm, plate thickness 1.5 mm) using a bar coater (No. 10) and dried to form a white primary coat film. I let you. A soldering iron trowel was applied as a heat source to the other surface (back surface) to heat a predetermined part. Depending on the degree of heating, the primary coating film was converted to a coating film with different transparency, and a design could be formed. FIG. 4 shows a reference example. In the present invention, the primary coating film was evaluated by the method of this reference example. The emulsion was applied to the surface of a copper plate (length 50 mm, width 30 mm, plate thickness 1 mm) with a No. 10 bar coater. A dried product (evaporation residue of emulsion or primary coating film) having a thickness of 5 μm obtained after drying at room temperature for 1 day was used as a sample coating film for measurement. On the sample coating film, a square filter paper having a side of 8 mm wetted with 30 μL of 1M aqueous copper sulfate solution as an electrolyte was placed, and a copper cylinder having a diameter of 8 mm was further placed to constitute a measurement cell. The sum of the Faraday resistance (generated between the copper plate and the electrolytic solution, between the copper column and the electrolytic solution) and the resistance of the coating film from the voltage generated when a weak current of 50 to 500 nA is passed between the copper plate and the bottom surface of the copper cylinder. Asked. The measured value 26Ω obtained without the sample coating film was taken as the Faraday resistance, but the resistance value of the coating film was obtained by subtracting it from the measured value which is the sum of the Faraday resistance and the resistance of the coating film. Although T20 became lower than T30, this cause seemed to be a measurement error resulting from the Faraday resistance being easily affected by the surface of the copper electrode (copper plate, copper cylinder).

  In the measurement of the resistance of the sample coat film, most of the prepared sample coat film remains unused. Therefore, the stability of the sample coat film was examined by rubbing the sample coat film used for the test with running fingers in running water for about 2 minutes. In this test method, the polymer fine particles are only loosely aggregated on the copper plate surface and are washed away unless the primary coat film is formed, and the polymer fine particles form the primary coat film and adhere (adhere) to the copper plate surface. It will not be washed away. The test result (sample coat film stability) is indicated as “-” when the sample coat film is completely washed away, “±” when the sample coat is partially washed away, and “+” when no runaway is seen. For the thing, the state of the part used for the electrical resistance measurement was observed and displayed in five levels as + when the color change was remarkable, + ± when the color change was considerably observed, and ++ when the degree of color change was small.

The schematic diagram of the primary coating film formed on the slide glass, and the coating film transparentized by heat processing. The portion with high transparency is shown in dark gray in the schematic diagram, and the brightness of gray is increased as the color becomes white. The example in which the ultraviolet absorber 1 described in Example 1 is applied is on the upper side, the example in which the ultraviolet absorber 3 described in Example 3 is applied is on the lower side, and the upper left and lower side portions in both the upper and lower examples are UV absorbers. Not applied.

When the ultraviolet absorbent 1 described in Example 1 was applied (upper side), the transparency of the primary coating film was high, so the primary coating film was shown in a slightly dark gray color. The primary coat film was clarified by heat treatment (the dark gray part on the right 1/4). When the ultraviolet absorbent 3 described in Example 3 was applied (lower side), the transparency of the primary coating film was low, and thus it was shown in light gray. The primary coat film was clarified by heat treatment (the dark gray part on the right 1/4). In this case, the degree of heating was changed to make it weakly heat-treated (slightly light gray part in the left inner quarter part of the figure, weakly heat-treated part and the part indicated by the arrow), but the transparency depends on the degree of heating. Different.
The ultraviolet-ray transmission spectrum (curve which shows low transmittance) of the primary coating film formed in Example 1 and the ultraviolet-ray transmission spectrum (curve which shows high transmittance) of the coating film clarified after the heat treatment. The ultraviolet transmission spectrum (curve which shows low transmittance) of the primary coating film formed in Example 3 and the ultraviolet transmission spectrum (curve which shows high transmittance) of the coating film which became transparent after heat treatment. FIG. 4 is a schematic view of a glass plate with an ultraviolet shielding coating film obtained in Example 4 of the present invention. The primary coat film is light gray because it has low transparency and reflects light rays. The portions heated to the letter shapes “U” and “V” are shown in black gray because the primary coating film became transparent. Regarding the shapes of “U” and “V” on the right side of the figure, the degree of heating was partially reduced. Although the transparency of the portion was low, it was shown as a gray outline blurring portion having a different brightness depending on the transparency.

Claims (3)

The following general formula (1);

(Wherein 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 group selected from the group consisting of nitrile group, R ³ is a linear or alkylene group having a carbon number of 1-12 with branched chain structure or -O-R ⁴ - represents a .R ⁴ Represents an alkylene group having a straight chain or branched chain structure and having 2 or 3 carbon atoms, R ⁵ represents a hydrogen atom or a methyl group.) Glass transition obtained by polymerizing a compound represented by as an essential monomer component It comprises polymer fine particles having a temperature of 40 ° C. or higher and polymer fine particles having a glass transition temperature of 30 ° C. or lower obtained by polymerizing the compound represented by the general formula (1) as an essential monomer monomer component. To Polymer emulsion. The emulsion according to claim 1, wherein the ratio (mass ratio) of the polymer fine particles is 40% or more. The emulsion according to claim 1 or 2, wherein the proportion (mass ratio) of the emulsifier is 2.5% or less.

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