JP2009091529A - Weather resistance improver for weak solvent paint and modified weak solvent paint - Google Patents

Abstract

（Ｒ₁は水素原子又は炭素数１〜２のアルキル基、Ｘは酸素原子又はイミノ基、Ｙは水素原子又は炭素数１〜２０のアルキル基又はアルコキシル基、Ｚは水素原子又はシアノ基を示す。）
【選択図】なしA weather resistance improver capable of imparting a high degree of weather resistance to a weak solvent paint and a weak solvent paint composition to which the improver is added.
0.1 to 50 parts by mass of an ethylenically unsaturated monomer (a) having a piperidyl group in the molecule of the general formula (I), and at least one alkyl (meth) acrylate having a C4 or higher alkyl group Seed monomer (b) 50-99.9 parts by mass and ethylenically unsaturated monomer (c) other than the monomer 0-20 parts by mass ((a), (b), (c) Is used as a weather resistance improver containing a copolymer (A) of an unsaturated monomer mixture consisting of 100 parts by mass.

(R ₁ is a hydrogen atom or an alkyl group having 1 or 2 carbon atoms, X is an oxygen atom or imino group, Y is a hydrogen atom or an alkyl group or alkoxyl group having 1 to 20 carbon atoms, and Z is a hydrogen atom or a cyano group. .)
[Selection figure] None

Description

  The present invention relates to a weather resistance improver for a weak solvent-based paint and a modified weak solvent-based paint. More specifically, the present invention is mainly used for the modification of a weak solvent-based paint and is added to the weak solvent-based paint. Thus, the present invention relates to a weather resistance improver and a modified coating composition that drastically improve the weather resistance performance of the paint.

  In recent years, in the paint field, from consideration of the global environment and painting work environment, so-called strong solvent-based paints using aromatic hydrocarbons such as toluene and xylene as media, aliphatic hydrocarbons such as mineral spirits, etc. Conversion to a weak solvent-based paint having a main component of the medium as a medium. Along with this, the required performance for weak solvent-based paints has become high, and the weather resistance performance of the coating film has recently been increasing as one of the most important performances. For this reason, the improvement is aimed at by various means, such as including high weather resistance components, such as silicone and fluorine.

On the other hand, the addition of a weather resistance improver such as an ultraviolet absorber, a hindered amine type radical scavenger (hereinafter HALS), and an antioxidant is used as an effective means for improving the weather resistance of various paints having different required performances. Among them, HALS is commercially available in various types due to its extremely high ability to improve weather resistance. However, since many of the commercially available HALS are of low molecular weight type, there is a problem that the water resistance of the coating film is lowered or the weathering performance requirement that is advanced by the bleed-out from the coating film cannot be satisfied. there were. In order to solve such a problem, a polymer obtained by copolymerizing a high concentration of reactive HALS having an unsaturated double bond capable of radical polymerization in the molecule is recovered in powder form and dissolved in a solvent-based paint to provide weather resistance. Has been proposed (Patent Document 1). However, all of the powder recovery polymers described in Patent Document 1 are soluble in strong solvents, but are insoluble in weak solvents, and cannot be used in weak solvent paints.
WO2006-126680

  The present invention has been made in view of the above circumstances, has a high anti-bleed out property, can provide a long-term weather resistance improving ability, and can be applied to weak solvent paints. An object of the present invention is to provide a weatherability improver and to provide a highly weather-resistant weak solvent-based paint to which the weatherability improver for the weak solvent-based paint is added.

  As a result of intensive studies aimed at solving the above problems, the inventors have obtained a copolymer obtained by polymerizing a monomer mixture obtained by mixing monomers having a specific structure within a specific ratio range. It has been found that those containing a polymer are soluble in a weak solvent paint and drastically improve the weather resistance of the weak solvent paint when a predetermined amount is added to the weak solvent paint. That is, the weak solvent type weather resistance improver of the present invention has 0.1 to 50 parts by mass of an ethylenically unsaturated monomer (a) having a piperidyl group in the molecule, and the alkyl group has 4 or more carbon atoms. 50 to 99.9 parts by mass of at least one monomer (b) selected from alkyl (meth) acrylates, and ethylenically unsaturated monomers (c) other than the monomers (a) and (b) A copolymer (A) obtained by polymerizing an unsaturated monomer mixture consisting of 0 to 20 parts by mass (however, the sum of (a), (b) and (c) is 100 parts by mass). This is a weather resistance improver for weak solvent paints.

(R ₁ is a hydrogen atom or an alkyl group having 1 to 2 carbon atoms, X is an oxygen atom or imino group, Y is a hydrogen atom or an alkyl group or alkoxyl group having 1 to 10 carbon atoms, and Z is a hydrogen atom or a cyano group. .)

  ADVANTAGE OF THE INVENTION According to this invention, the weak solvent type coating material which has the weather resistance improver for weak solvent type coating materials which improves the weather resistance of a weak solvent type coating material dramatically, and high weather resistance can be provided.

  The weather resistance improver for weak solvent paints of the present invention has 0.1 to 50 parts by mass of an ethylenically unsaturated monomer (a) having a piperidyl group in the molecule, and the alkyl group has 4 or more carbon atoms. 50 to 99.9 parts by mass of at least one monomer (b) selected from alkyl (meth) acrylates, and ethylenically unsaturated monomers (c) other than the monomers (a) and (b) A copolymer (A) obtained by polymerizing an unsaturated monomer mixture consisting of 0 to 20 parts by mass (however, the sum of (a), (b) and (c) is 100 parts by mass). This is a weather resistance improver for weak solvent paints.

(R ₁ is a hydrogen atom or an alkyl group having 1 to 2 carbon atoms, X is an oxygen atom or imino group, Y is a hydrogen atom or an alkyl group or alkoxyl group having 1 to 20 carbon atoms, and Z is a hydrogen atom or a cyano group. .)

  The copolymer (A) constituting the weather resistance improver (hereinafter referred to as weather resistance improver) for weak solvent paints according to the present invention has the ability to improve the weather resistance of the weak solvent paint to which the weather resistance improver is added. From the above, when the total monomer amount during polymerization is 100 parts by mass, the content of the unsaturated monomer (a) represented by the general formula (I) needs to be 0.1 to 50 parts by mass. is there. If the content of the monomer (a) is 0.1 parts by mass or more, sufficient weather resistance can be imparted within a range of the addition amount that does not significantly reduce one or more of the properties of the paint to be added. . Moreover, if the quantity of a monomer (a) is 50 mass parts or less, not only the solubility to a weak solvent can be ensured but the stability at the time of superposition | polymerization can also be ensured. As content of a monomer (a), 5-50 mass parts is preferable, and 10-50 mass parts is the most preferable.

  As the monomer (a), one having an ultraviolet light stabilizing function can be used. 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) acryloyloxy-2,2,6,6-tetramethylpiperidine and the like. Among the above monomers, a methacrylate monomer in which R1 = methyl group is preferred from the viewpoint of the ability of improving the weather resistance of the coating film containing the weather resistance improver of the present invention. These may be used alone or in combination of two or more as required.

  Further, the weather resistance improver of the present invention has an alkyl group having 4 carbon atoms as a copolymerization component of the monomer (a) from the viewpoint of solubility in a weak solvent paint to which the weather resistance improver is added. It is necessary to select at least one monomer (b) selected from the alkyl (meth) acrylates as described above and set the content thereof in the range of 50 to 99.9 parts by mass. If at least one monomer is selected as the monomer (b) and the content in the copolymer (A) is 50 parts by mass or more, sufficient solubility in a weak solvent can be secured. . When the amount of the monomer (b) exceeds 99.9 parts by mass, the amount of the monomer (a) is relatively decreased, which is not preferable. As content of a monomer (b), 50-95 mass parts is more preferable, and 50-90 mass parts is the most preferable.

Examples of the monomer (b) include n-butyl (meth) acrylate, i-butyl (meth) acrylate, t-butyl (meth) acrylate, normal hexyl (methacrylate), n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, t-octyl (meth) acrylate, cyclohexyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) Examples thereof include acrylate, pt-butylcyclohexyl (meth) acrylate, and isobonyl (meth) acrylate. Among these monomers, it contains at least one monomer selected from t-butyl methacrylate and cyclohexyl methacrylate as an essential component from the viewpoint of handling the solid content and improving the weather resistance of the added paint. It is particularly preferable that the content of these monomers is 50 parts by mass or more. Although the solubility parameter (Sp value) of the monomer (b) is not particularly defined, it is 20.10 ((J / cm ³ ) in terms of the Fedors Sp value in terms of the solubility of the copolymer (A) in a weak solvent. 1/2) or less is preferable. The said monomer can be used individually by 1 type or in combination of 2 or more type as needed.

  In addition, the weather resistance improver of the present invention may use a monomer (c) other than the monomers (a) and (b) as a copolymerization component as necessary, but the content thereof is 20 It must be less than or equal to parts by mass. If content of a monomer (c) is 20 mass parts or less, the solubility to a weak solvent is securable. As a monomer (c), 15 mass parts or less are preferable, and 10 mass parts or less are more preferable.

  Examples of the monomer (c) include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, i-propyl (meth) acrylate, methyl (eta) acrylate, and ethyl (eta) acrylate. , (Meth) acrylonitrile, 2-hydroxyethyl (meth) acrylate, 2- (3-) hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, glycerol mono (meth) acrylate, glycidyl (meth) acrylate, Tetrahydrofurfuryl (meth) acrylate, (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylate, dimethyl fumarate, diethyl fumarate, dibutyl fumarate, dimethyl itaconate, dimethyl maleate, di maleate Chill, dibutyl maleate, diethyl itaconate, dibutyl itaconate, vinyl pyridine, vinyl imidazole, (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylate, styrene, vinyl pyridine, vinyl imidazole vinyl chloride, vinylidene chloride, Examples thereof include vinyl fluoride, vinylidene fluoride, tetrafluoroethylene, styrene, α-methylstyrene, vinyl toluene, vinyl acetate, vinyl ether and the like.

  As the monomer (c), select a reactive antioxidant having a functional group containing an antioxidant ability such as reactive UVA having an unsaturated double bond and a UV-absorbing functional group in the molecule or hindered phenol. It is preferable because a higher ability to improve weather resistance is obtained. The said monomer (c) can be used individually by 1 type or in combination of 2 or more types.

  The “weak solvent” referred to in the present invention refers to a solvent having an aliphatic hydrocarbon content of 50% by mass or more in an organic solvent that dissolves a coating resin. As a single-component solvent, n- In addition to butane, n-hexane, n-heptane, n-octane, isononane, n-decane, n-dodecane, and the like, terpene oil and mineral spirits can be used. In addition to the above single-component solvents, mixed component solvent systems include “LAWS”, “HAWS” (manufactured by Shell Chemical Co., Ltd.), “Pegasol 3040”, “Pegasol AN45” (manufactured by Exxon Mobil Corporation), etc. Is mentioned.

  Further, the “weak solvent-based paint” in the present invention is a general term for a paint obtained by dissolving or dispersing a thermoplastic resin in the above weak solvent. As the thermoplastic resin, acrylic, fluorine-based, chlorine-based, urethane-based , Polyester-based, aromatic-based, and silicone-based thermoplastic resins. The said thermoplastic resin can be used individually by 1 type or in combination of 2 or more types.

  The polymerization method for obtaining the copolymer (A) constituting the weather resistance improver of the present invention is not particularly defined, and a known polymerization method such as emulsion polymerization, solution polymerization, suspension polymerization, bulk polymerization, etc. is used. Can be polymerized. In addition, when polymerization is performed using a polymerization method capable of obtaining a particle structure such as an emulsion polymerization method, a soap-free emulsion polymerization method, or a drop suspension polymerization method, the particle structure may be a single layer structure or a multilayer structure. However, in the case of multilayer structure particles, a three-layer structure or less is preferable from the viewpoint of economy.

  As the emulsifier when polymerizing the weather resistance improver of the present invention by emulsion polymerization, various conventionally known anionic or nonionic emulsifiers, polymer emulsifiers, and unsaturated double radicals capable of radical polymerization in the molecule. Examples thereof include a reactive emulsifier having a bond. As the emulsifier, trade names “New Coal 560SF”, “562SF”, “707SF”, “707SN”, “714SF”, “723SF”, “723SF”, “740SF”, “2308SF” manufactured by Nippon Emulsifier Co., Ltd. "Same 2320SN", "Same 1305SN", "Same 271A", "Same 271NH", "Same 210", "Same 220", "Same RA 331", "Same RA 332", Kao's trade name "Latemuru B-" Anionic emulsifiers such as “118E”, “Lebenol WZ”, “Neopelex G15”, trade name “Hytenol N08” manufactured by Daiichi Kogyo Seiyaku Co., Ltd., for example, “Nonipol 200”, “New Pole PE” manufactured by Sanyo Chemical Nonionic emulsifiers such as “-68” and the like. Examples of the polymer emulsifier include polyvinyl alcohol, polyhydroxyethyl (meth) acrylate, polyhydroxypropyl (meth) acrylate, and polyvinylpyrrolidone. Examples of reactive emulsifiers include trade names “Antox MS-60” and “MS-2N” manufactured by Nippon Emulsifier Co., Ltd., trade names “Eleminol JS-2” manufactured by Sanyo Chemical Co., Ltd., “Latemul S-120” manufactured by Kao Corporation, “S-180”, “S-180A”, “PD-104”, trade names “ADEKA rear soap SR-10”, “SE-10”, trade names made by Daiichi Kogyo Seiyaku Co., Ltd. Reactive anionic emulsifiers such as “Aqualon KH-05”, “Same KH-10”, “Same HS-10”, for example, trade names “Adekaria soap NE-10”, “Same ER-10” manufactured by ADEKA, “Same NE-20”, “Same ER-20”, “Same NE-30”, “Same ER-30”, “Same NE-40”, “Same ER-40”, trade names of Daiichi Kogyo Seiyaku Co., Ltd. “Aqualon RN-10”, “RN-20”, “RN” 30 ", such as reactive nonionic emulsifiers such as" the RN-50 ", and the like. As the emulsifier when the weather resistance improver of the present invention is obtained by emulsion polymerization, a reactive emulsifier is preferably used from the viewpoint of the weather resistance improving ability of the weak solvent-based paint containing the weather resistance improver of the present invention. These may be used alone or in combination of two or more as required. The unsaturated monomer of the present invention does not contain a reactive emulsifier.

  Examples of the solvent for polymerizing the copolymer (A) constituting the weather resistance improver of the present invention by a solution polymerization method include toluene, xylene, other aromatic solvents; ethyl acetate, butyl acetate. , Ester solvents such as cellosolve acetate; known organic solvents such as ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone may be used to recover solids after polymerization, or may be polymerized in weak solvents such as mineral spirits. The copolymer (A) solution may be used as it is as a weather resistance improver.

  Examples of the dispersion stabilizer used when the copolymer (A) constituting the weather resistance improver of the present invention is polymerized by the suspension polymerization method include calcium phosphate, calcium carbonate, aluminum hydroxide, and starch silica. Water-insoluble inorganic compounds, nonionic polymer compounds such as polyvinyl alcohol, polyethylene oxide, and cellulose derivatives, polyacrylic acid and salts thereof, polymethacrylic acid and salts thereof, and copolymers of methacrylic acid esters and methacrylic acid and salts thereof Anionic polymer compounds such as can be used. Among them, anionic polymer compounds can maintain dispersion stability in a very small amount and are very excellent as a dispersant for suspension polymerization. These dispersion stabilizers may be used alone or in combination of two or more.

  What is necessary is just to collect solid content by the method suitable for each polymerization method for the copolymer (A) which comprises the weather resistance improvement agent of this invention polymerized by various polymerization methods. For example, when polymerization is performed by emulsion polymerization, the resin content may be recovered by a method such as a spray drying method, a salting out coagulation method, a centrifugal separation method, or a freeze drying method. As a solid content recovery method by the spray drying method, an emulsion dispersion obtained by emulsion polymerization is spray-dried at an inlet temperature: 120 to 220 ° C. and an outlet temperature: 40 to 90 ° C. with a spray dryer, and powder is recovered. can do. The outlet temperature is preferably 40 to 80 ° C. from the viewpoint of the ability to disintegrate the recovered secondary particles into primary particles, and 40 to 70 ° C. is particularly preferable. As a recovery method by a coagulation method, the emulsified dispersion is brought into contact with a coagulant at 30 to 60 ° C., and coagulated with stirring to form a slurry, which can be dehydrated and dried to recover the powder. Examples of the coagulant used in the salting-out coagulation method include inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid, organic acids such as formic acid and acetic acid, and organic salts such as aluminum sulfate, magnesium sulfate, calcium acetate, and calcium sulfate. Although there is a risk of hindered amine group deactivation by an acid, when coagulation with an acid such as hydrochloric acid is performed, it is preferable to wash with a basic aqueous solution such as ammonia water after powder recovery. Moreover, when it superposes | polymerizes by solution polymerization, what is necessary is just to collect | recover by methods, such as a reprecipitation method and solvent volatilization removal method. When the polymerization is performed by suspension polymerization, filtration and recovery are the simplest.

  The copolymer (A) constituting the weather resistance improver of the present invention can be polymerized using the monomers (a), (b) and (c) and using a radical polymerization initiator. . As the polymerization initiator, those generally used for radical polymerization can be used. Specific examples thereof include persulfates such as potassium persulfate, sodium persulfate and ammonium persulfate; azobisisobutyronitrile. 2,2′-azobis (2-methylbutyronitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile) ), Oil-soluble azo compounds such as 2-phenylazo-4-methoxy-2,4-dimethylvaleronitrile; 2,2′-azobis {2-methyl-N- [1,1-bis (hydroxymethyl) -2 -Hydroxyethyl] propionamide}, 2,2′-azobis {2-methyl-N- [2- (1-hydroxyethyl)] propionamide}, 2,2′-azobis 2-methyl-N- [2- (1-hydroxybutyl)] propionamide}, 2,2′-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] and its salts, 2, 2′-azobis [2- (2-imidazolin-2-yl) propane] and its salts, 2,2′-azobis [2- (3,4,5,6-tetrahydropyrimidin-2-yl) propane] and Its salts, 2,2′-azobis {2- [1- (2-hydroxyethyl) -2-imidazolin-2-yl] propane} and its salts, 2,2′-azobis (2-methylpropionamidine) and Its salts 2,2'-azobis (2-methylpropyneamidine) and its salts, 2,2'-azobis [N- (2-carboxyethyl) -2-methylpropionamidine] and Water-soluble azo compounds such as salts thereof; organic peroxides such as benzoyl peroxide, cumene hydroperoxide, t-butyl hydroperoxide, t-butylperoxy-2-ethylhexanoate, t-butylperoxyisobutyrate Examples thereof include oxides. These initiators can be used alone or as a mixture of two or more. Further, when the polymerization is carried out by an emulsion polymerization method, it is advantageous to use a reducing agent such as sodium bisulfite, ferrous sulfate, ascorbate or the like in combination with a radical polymerization catalyst.

  The weight average molecular weight (hereinafter referred to as Mw) of the copolymer (A) constituting the weather resistance improver of the present invention is not particularly defined, but is preferably in the range of 5,000 to 200,000. If Mw is 5,000 or more, there will be no problem in the elution from a coating film, and the long-term weather resistance improvement ability will be expressed. On the other hand, if Mw is 200,000 or less, good solubility in a weak solvent can be secured. The range of Mw is more preferably 5,000 to 100,000, and particularly preferably 5,000 to 50,000. The method for adjusting Mw is not particularly defined, but it is also an effective means to use a chain transfer agent in addition to the method by adjusting the amount of initiator.

  Examples of the chain transfer agent include mercaptans such as n-dodecyl mercaptan, t-dodecyl mercaptan, n-octyl mercaptan, n-tetradecyl mercaptan, n-hexyl mercaptan, n-butyl mercaptan; carbon tetrachloride, ethylene bromide and the like. Halogen compound; a known chain transfer agent such as α-methylstyrene dimer may be used. What is necessary is just to change the usage-amount of a chain transfer agent according to the kind of chain transfer agent to be used, or the structural ratio of an unsaturated monomer. The said chain transfer agent can be used individually or in combination of 2 or more types.

  Moreover, although the glass transition temperature (Tg) of the copolymer (A) which comprises the weather resistance improving agent of this invention is not prescribed | regulated, it is preferable that it is 50 degreeC or more at the point of handling property. In particular, when the multilayer structure particles are formed using an emulsion polymerization method, it is preferable to form a copolymer layer having a Tg of 50 ° C. or more as the outermost layer. In addition, as said Tg, the calculated glass transition temperature calculated | required by the formula of Fox is used. The formula of Fox is a relational expression between the glass transition temperature (° C.) of the copolymer and the glass transition temperature (° C.) of the homopolymer obtained by homopolymerizing each of the copolymer monomers, as shown below. .

1 / (273 + Tg) = Σ (W _i / (273 + Tg _i ))
[Wherein W _i represents the mass fraction of monomer i, and Tg _i represents the Tg (° C.) of the homopolymer of monomer i. ]

  In addition, as Tg of a homopolymer, the value specifically described in "Polymer Handbook 3rd Edition" (A WILEY-INTERSCIENCE PUBLICATION, 1989) can be used.

  As the weather resistance improver of the present invention, the copolymer (A) having the same composition may be used alone, or two or more copolymers (A) having different compositions may be used in combination. Moreover, the weather resistance improver of the present invention may be used by directly adding to a weak solvent-based paint, or once dissolved in a weak solvent, the weak solvent solution is added to the weak solvent-based paint and used. Also good.

  In addition, the weather resistance improver of the present invention is preferably used in combination with an ultraviolet absorber (UVA) from the viewpoint of the ability to improve weather resistance. As UVA that can be used in combination with the weather resistance improver of the present invention, known UVAs such as benzophenone UVA, benzotriazole UVA, inorganic UVA, and hydroxyphenyltriazine UVA can be used. Of these UVAs, combined use with hydroxyphenyltriazine-based UVA is most preferred in terms of the ability to improve the weather resistance of the coating film. Examples of the benzophenone UVA include Sumitomo Chemical's trade name “Sumisorb 130”, BASF Japan's trade names “Uvinul 3049”, “Same 3050”, and the like. Examples of the benzotriazole UVA include Ciba Special. Trade names “Tenubin PS”, “99-2”, “109”, “384-2”, “900”, “928”, “1130”, products of Sumitomo Chemical Co., Ltd. Names “Sumisorb 200”, “250”, “300”, trade names “ULS-1935LH” manufactured by Yushi Kogyo Co., Ltd., “JF-77”, “78” 79 ”,“ 80 ”,“ 83 ”, and the like, and examples of the inorganic UVA include“ Nidolal W-100 ”manufactured by Taki Chemical Co., Ltd. Examples of the roxyphenyltriazine-based UVA include “Tinubin 400”, “405”, “460”, “477DW”, and “479” manufactured by Ciba Specialty Chemicals. These UVAs may be used alone or in combination of two or more. The amount of UVA added to the weak solvent-based paint containing the weather resistance improver of the present invention is not particularly defined, but the sum of the weather resistance improver, the solid content in the added weak solvent paint and UVA is 100 parts by mass. Is preferably 1.5 parts by mass or less from the viewpoint of the colorability of the coating film.

  The weather resistance improver of the present invention can be applied by a known coating method such as spray coating or roller coating after adding a predetermined amount to the weak solvent-based paint to be added. The addition amount of the weather resistance improver of the present invention is not particularly defined, but when the sum of the solid content in the weather resistance improver and the weak solvent-based paint to be added is 100 parts by mass, the range is 0.1 to 30 parts by mass. It is preferable to add in. When the added amount of the weather resistance improver of the present invention is less than 0.1 parts by mass, sufficient weather resistance improving ability may not be exhibited. Moreover, if the addition amount is 30 parts by mass or less, one or more of the characteristics of the added weak solvent-based paint will not be significantly reduced. In addition, various pigments, antifoaming agents, pigment dispersants, leveling agents, matting agents, flame retardants, UV absorbers are used to develop high performance in the weather resistance improver and weak solvent paints containing the same. Agents, antioxidants, heat resistance improvers, slip agents, preservatives, antibacterial agents and the like may be added.

  Moreover, you may use the weather resistance improver of this invention for various thermoplastic resin uses.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited at all by these. In the following description, “part” is based on mass.

<Measurement of weight average molecular weight (Mw)>
0.1 g of each of the weather resistance improvers of Examples 1 to 11 and Comparative Examples 1 and 2 is collected in a sample bottle, 10 g of tetrahydrofuran (THF) is added, and the mixture is allowed to stand overnight at room temperature. The prepared sample solution was measured under the following conditions using HLC-8120 manufactured by Tosoh Corporation, and the value converted to standard polystyrene was defined as the weight average molecular weight (Mw).

[GPC measurement conditions]
Column: TSK-gel TSL-gel SuperHM-M x 4 (6.0mmI.D. x 15cmL)
Eluent: THF
Flow rate: 0.6ml / min
Injection volume: 20μl
Column temperature: 40 ° C
Detector: Differential refractive index detector (RI)

<Weak solvent solubility test>
The weather resistance improvers of Examples 1 to 11 and Comparative Examples 1 to 3 are mixed with mineral spirit so that the solid content concentration is 5% by mass and stirred at 40 ° C. for 1 hour. Further, the state of the solution after standing at 40 ° C. for 3 days was visually judged according to the following criteria.

○: Transparent solution, judged to be soluble ×: Precipitate is present, or the solution is cloudy, judged to be insoluble or partially insoluble

  As a result of the weak solvent solubility test, the following test was conducted on the weather resistance improver judged to be soluble.

<Create a clear coated plate>
A weather resistance improver and mineral spirit are blended with acrylic resin “BR-118” (trade name, manufactured by Mitsubishi Rayon Co., Ltd.) as a base weak solvent paint resin in the proportions shown in Table 1. When it was confirmed that the resin component was sufficiently dissolved, filtration was performed using a 100 mesh nylon candy to obtain a clear paint for evaluation. The paint prepared above was applied to a zinc phosphate-treated steel plate (“Bonderite” # 100 treated steel plate, thickness 0.8 mm, 70 mm × 150 mm) with a bar coater so that the dry film thickness was 30 μm. After forcibly drying for 0.5 hour, the plate further dried overnight at 40 ° C. was used as a test coated plate for the weather resistance test.

<Accelerated weather resistance test>
The test coating plate prepared by the above method is put in an evaluation apparatus “Daipura Metal Weather” KU-R4-W type (trade name, manufactured by Daipura Wintes Co., Ltd.), and test cycle: irradiation 4 hours / condensation 4 hours, UV Intensity: 85 mW / cm ² , Black panel temperature: 63 ° C. during irradiation / 30 ° C. during condensation, Humidity: 50% RH during irradiation / 96% RH during condensation, 60 ° gloss retention after 300 hours Was determined according to the following criteria. The 60 ° gloss was measured using a polarization gloss meter “VG-2000 type” manufactured by Nippon Denshoku Industries Co., Ltd.

“6”: Gloss retention is 90% or more “5”: Gloss retention is 80% or more and less than 90% “4”: Gloss retention is 75% or more and less than 80% “3”: Gloss retention is 70% or more Less than 75% “2”: Gloss retention is 60% or more and less than 70% “1”: Gloss retention is less than 60%

<Water resistance test>
The test coated plate prepared by the above method was immersed in a 60 ° C. constant temperature water bath for 3 days, and the ΔL value immediately after the pulling was used as a water resistance index, and the determination was made according to the following criteria. The ΔL value was measured using a spectrocolor meter “SE-2000 type” manufactured by Nippon Denshoku Industries Co., Ltd.

“◯”: ΔL <3
“×”: ΔL ≧ 3

<Synthesis of Dispersant (a) for Suspension Polymerization>
165 g of 2-sulfoethyl sodium methacrylate, 25 g of potassium methacrylate, 30 g of methyl methacrylate and 2250 g of deionized water were heated to 50 ° C. with stirring in a nitrogen atmosphere in a separable flask equipped with a condenser having an internal volume of 3000 ml. Thereafter, 0.25 g of ammonium persulfate was added as a polymerization initiator, and the temperature was raised to 60 ° C. Meanwhile, simultaneously with the addition of the polymerization initiator, methyl methacrylate was continuously added dropwise at a rate of 0.4 g / min for 75 minutes. When stirring was continued at 60 ° C. for 6 hours, a transparent polymer solution having a viscosity of 1000 mPa · s was obtained. This was adjusted to 10% solids with deionized water, and used as Dispersant A used during suspension polymerization.

<Example>
Example 1
An emulsion blended in a flask equipped with a stirrer, a reflux condenser, a temperature controller, a dropping pump, and a nitrogen inlet tube, with 45 parts of deionized water and then 0.2 part of a 28% aqueous ammonia solution in the proportions shown in Table 1. Was added to a reaction vessel, the temperature inside the reaction vessel was replaced with nitrogen, and the temperature was raised to 75 ° C. Then, an initiator solution in which 0.1 part of ammonium persulfate (polymerization initiator) was dissolved in 5 parts of water was prepared. In addition, seed particles were formed. After measuring the temperature of the solution with a thermometer and confirming the exothermic peak, the remainder of the emulsion was added dropwise at an internal temperature of 75 ° C. over 4 hours, and further aged for 2 hours at an internal temperature of 75 ° C. for emulsion polymerization. To form an emulsified dispersion. The obtained emulsified dispersion was cooled to room temperature, and then sprayed at an inlet temperature of 170 ° C., an outlet temperature of 60 ° C., and an atomizer speed of 25,000 rpm using a spray dryer (manufactured by Okawahara Chemical Co., Ltd., type L-8). It was dried and solid was recovered as a weather resistance improver. It was confirmed that the obtained weather resistance improver was soluble by the solubility test method. For this reason, after preparing the coating composition at the ratio shown in Table 1, a test plate was prepared by the above-described method and subjected to a weather resistance test. The results are shown in Table 1.

(Examples 2 to 5)
Emulsion polymerization having the composition shown in Table 1 was carried out in the same manner as in Example 1, and the resulting emulsion dispersion was recovered as a solid by the spray drying method as in Example 1. Since the obtained weather resistance improver was soluble, a test composition was prepared after preparing a coating composition blended at the ratio shown in Table 1, and subjected to a weather resistance test. The results are shown in Table 1.

(Example 6)
A reaction vessel equipped with a stirrer and a thermometer was charged with 145 parts by weight of deionized water, 0.5 part by weight of Dispersant A, 0.1 part by weight of sodium sulfate, and 0.1 part by weight of 28% aqueous ammonia solution. And 0.6 part by weight of lauroyl peroxide as a polymerization initiator. While stirring the contents, the temperature was raised from 40 ° C. to 90 ° C. over 1 hour and 25 minutes, so that the temperature of the contents reached 90 ° C. After reaching 90 ° C., the mixture was further stirred for 1 hour 30 minutes and then cooled to obtain a suspension of polymer particles. The obtained suspension was filtered with a nylon filter cloth having a mesh opening of 45 μm, thoroughly washed with deionized water, and then dried at 50 ° C. for 24 hours to obtain a weather resistance improver. Since the obtained weather resistance improver was soluble, after preparing the coating composition blended at the ratio shown in Table 1, a test plate was prepared and subjected to a weather resistance test. The results are shown in Table 1.

(Example 7)
The suspension polymerization having the composition shown in Table 1 was performed in the same manner as in Example 6, and the resulting suspension was recovered in solid form by the same filtration method as in Example 6. Since the obtained weather resistance improver was soluble, a test composition was prepared after preparing a coating composition blended at the ratio shown in Table 1, and subjected to a weather resistance test. The results are shown in Table 1.

(Example 8)
180 parts by mass of “ENEOS Mineral Spirit A” (trade name, manufactured by Shin Nippon Oil Co., Ltd.) and a single amount shown in Table 1 in a flask equipped with a stirrer, a reflux condenser, a temperature controller, a dropping funnel and a nitrogen introduction tube The body mixture was charged, stirred while blowing nitrogen from a nitrogen introduction tube, and heated to 50 ° C. Thereafter, 0.5 part by mass of azobisisobutyronitrile (AIBN) dissolved in 20 parts by mass of “mineral spirit A” was added, the temperature was raised to 70 ° C. with stirring, the reaction was performed for 8 hours, and the solid content concentration A 33 mass% copolymer (A) solution was obtained. The cooled copolymer (A) solution is used as it is as a weak solvent-based weather resistance improver, and 92 parts by mass of acrylic resin (α) is dissolved in 184 parts by mass of “mineral spirit A”. 24 parts by mass of the copolymer (A) solution was added to obtain a weak solvent-based coating composition having a blending ratio shown in Table 1. A test plate was prepared using the obtained coating composition and subjected to a weather resistance test. The results are shown in Table 1.

(Examples 9 to 11)
A solution obtained by performing solution polymerization of the composition shown in Table 1 in the same manner as in Example 8, and blending the obtained weather resistance improver solution in the same manner as in Example 8 in the proportions shown in Table 1 After preparing the composition, a test plate was prepared and subjected to a weather resistance test. The results are shown in Table 1.

(Comparative Example 1)
Emulsion polymerization having the composition shown in Table 1 was carried out in the same manner as in Example 1, and the resulting emulsion dispersion was recovered as a solid by the spray drying method as in Example 1. Since the obtained weather resistance improver was insoluble in the dissolution test method, the weather resistance test was abandoned.

(Comparative Example 2)
The suspension polymerization having the composition shown in Table 1 was performed in the same manner as in Example 6, and the resulting suspension was recovered in solid form by the same filtration method as in Example 6. Since the obtained weather resistance improver was insoluble in the dissolution test method, the weather resistance test was abandoned.

(Comparative Example 3)
Using “Tinuvin-770” (trade name, manufactured by Ciba Specialty Chemicals) as a weather resistance improver, a coating composition was prepared at a ratio shown in Table 1, a test plate was prepared, and subjected to a weather resistance test. . The results are shown in Table 1.

(Comparative Example 4)
A weather resistance improver was not used, and after preparing a coating composition at a ratio shown in Table 1, a test plate was prepared and subjected to a weather resistance test. The results are shown in Table 1.

Abbreviations in the table are as follows.
HALS1: 4-methacryloyloxy-2,2,6,6-tetramethylpiperidine HALS2: 4-methacryloyloxy-1,2,2,6,6-pentamethylpiperidine HALS3: Tinuvin-770 (trade name, Ciba Specialty (Chemicals)
t-BMA: Tertiary butyl methacrylate CHMA: Cyclohexyl methacrylate n-BMA: Normal butyl methacrylate i-BMA: Isobutyl methacrylate n-BA: Normal butyl acrylate 2EHA: 2-ethylhexyl acrylate MMA: Methyl methacrylate St: Styrene 2HEMA: 2-hydroxyethyl methacrylate n-DM: normal dodecyl mercaptan emulsifier (1): “ADEKA rear soap SR-10” (trade name, manufactured by ADEKA Corporation)
Dispersant (a): 2-sulfoethyl sodium methacrylate / potassium methacrylate / methyl methacrylate copolymer 10% by mass aqueous solution acrylic resin (α): “BR-118” (trade name, manufactured by Mitsubishi Rayon Co., Ltd.)
Weak solvent 1: “ENEOS Mineral Spirit A” (trade name, manufactured by Nippon Oil Corporation)
UVA1: “Tinubin 400” (trade name, manufactured by Ciba Specialty Chemicals Co., Ltd.)
UVA2: “Tinubin 99-2” (trade name, manufactured by Ciba Specialty Chemicals Co., Ltd.)

  As can be seen from Table 1, the weather resistance improver of the present invention has excellent solubility in weak solvents, and can impart excellent weather resistance improving ability when added to weak solvent paints. On the other hand, the composition ratio of the monomers (a) and (b) in Comparative Example 1 and the composition ratio of the monomer (c) in Comparative Example 2 are not within the range specified in the present invention. Does not dissolve in weak solvents. In Comparative Example 3, a low molecular weight type weather resistance improver is used. However, the water resistance of the coating film is lowered, and the weather resistance improving ability is considered to be based on elution from the coating film of the weather resistance improving agent. Is insufficient. Therefore, it can be seen that the weather resistance improving agent of the present invention is extremely useful as a weather resistance improving agent for weak solvent paints.

  The weather resistance improver of the present invention includes cement mortar, slate board, gypsum board, extruded board, foamed concrete, metal, glass, porcelain tile, asphalt, wood, waterproof rubber material, plastic, calcium silicate base material, and the like. By adding to a weak solvent-based paint used for the surface finishing of the material, the weather resistance can be improved over a long period of time, which is extremely useful industrially.

Claims (4)

0.1 to 50 parts by mass of an ethylenically unsaturated monomer (a) having a piperidyl group in the molecule represented by the following general formula (I), and an alkyl (meta) having 4 or more carbon atoms in the alkyl group ) At least one monomer selected from acrylate (b) 50-99.9 parts by mass, and ethylenically unsaturated monomer (c) 0 other than the monomers (a) and (b) A weak solvent containing a copolymer (A) obtained by polymerizing an unsaturated monomer mixture comprising ˜20 parts by mass (provided that the total of (a), (b) and (c) is 100 parts by mass) Weathering improver for paints.

(R ₁ is a hydrogen atom or an alkyl group having 1 to 2 carbon atoms, X is an oxygen atom or imino group, Y is a hydrogen atom or an alkyl group or alkoxyl group having 1 to 20 carbon atoms, and Z is a hydrogen atom or a cyano group. .)   A weak solvent-based paint comprising the weather resistance improver according to claim 1.   Furthermore, the weak solvent type coating material of Claim 2 containing a ultraviolet absorber.   A highly weather-resistant coating film obtained by forming the weak solvent paint according to claim 2 into a film.