JP2016011417A - Binder for coating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a binder for coating, excellent in adhesiveness not only with a polypropylene-made substrate, but also a cycloolefin polymer-made substrate and light resistance.SOLUTION: There is provided a binder for coating containing a polyolefin resin and an aqueous medium, where the polyolefin resin contains an olefin component and an unsaturated carboxylic acid component as a copolymer component, the olefin component consists of propylene and butene, the mass ratio between the propylene and the butene (propylene/butene) is 60/40 to 95/5 and the content of the unsaturated carboxylic acid component as the copolymer component is 1 pts.mass or more based on 100 pts.mass of the olefin component and an unsaturated carboxylic acid monomer amount in a dry residue of the binder for coating is 10,000 ppm or less.

Description

  The present invention relates to a coating binder having excellent adhesion to a polyolefin resin substrate.

  Polyolefin resins such as polypropylene (PP) are excellent in electrical properties, mechanical properties, chemical properties, formability, hygiene, recyclability, etc., and are used in automobile parts, electrical / electronic parts, packaging materials, etc. . However, since a polyolefin resin generally has no polar group in the molecular chain, there is a problem that it is difficult to apply or adhere to a polyolefin resin.

  In order to improve the paintability and adhesion to the polyolefin resin, a pretreatment is performed in which the surface of the substrate made of the polyolefin resin is activated by plasma treatment or gas flame treatment in advance. However, this pretreatment method has a complicated process and involves a lot of equipment and time, and the surface treatment effect varies due to the complexity of the shape of the substrate and the influence of pigments and additives in the resin. Has the disadvantage of producing.

  In order to eliminate such drawbacks, there is a method of undercoating a primer on the surface of the substrate. For example, chlorinated polyolefin resin is often used as a primer for polypropylene bumpers of automobiles. However, since chlorinated polyolefin resin generates harmful substances such as acid gas when discarded by incineration, it has recently tended to be refrained from the viewpoint of environmental considerations. In addition, since the primer is coated on the substrate and then coated with the paint, there is a problem that the process is complicated.

  Recently, among polyolefin resins, cycloolefin polymer (COP), which has excellent properties such as low water absorption, high transparency, high heat resistance, low dielectric constant, and low dielectric loss tangent, has attracted attention. Use in various fields such as applications, automobile applications, packaging applications, and electronic member applications is being studied. However, the cycloolefin polymer has a problem that paintability and adhesion are inferior like other polyolefin resins, and a material for solving this problem has been desired.

  In view of the above background, a paint having excellent adhesion to a polyolefin resin substrate such as polypropylene or cycloolefin polymer has been developed without pretreatment or primer treatment. For example, Patent Document 1 discloses a technique for obtaining an acid-modified polyolefin resin aqueous dispersion without substantially using a surfactant. This acid-modified polyolefin resin aqueous dispersion uses a surfactant. Therefore, it is described that the coating film has excellent chemical resistance and can be suitably used as a binder for paints.

International Publication No. 2004/104090

However, when the acid-modified polyolefin resin aqueous dispersion disclosed in Patent Document 1 is used as a binder for paints, it adheres to a polypropylene substrate, but the cycloolefin polymer substrate may have poor adhesion. there were.
In addition, when the paint is applied to a substrate and used outdoors for a long period of time, the coating layer may fade and the color tone may change (it is inferior in light resistance), and there is room for improvement.

  The present invention eliminates the above-mentioned disadvantages of the prior art, and uses an acid-modified polyolefin resin aqueous dispersion finely and stably containing non-chlorine polyolefin resin fine particles having a specific composition in an aqueous medium. An object of the present invention is to provide a binder composition for paints that is excellent in adhesion to a substrate made of cycloolefin polymer as well as a substrate made of cycloolefin polymer, and excellent in light resistance of the coating film. .

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have used a paint binder having a specific configuration as the acid-modified polyolefin resin and having a monomer amount of the acid-modified component equal to or less than a specific amount. The present inventors have found that the problem can be solved and have reached the present invention.

That is, the gist of the present invention is as follows.
(1) A coating binder containing a polyolefin resin and an aqueous medium,
The polyolefin resin contains an olefin component and an unsaturated carboxylic acid component as a copolymer component,
The olefin component consists of propylene and butene,
The mass ratio of propylene to butene (propylene / butene) is 60/40 to 95/5,
The content of the unsaturated carboxylic acid component as the copolymer component is 1 part by mass or more with respect to 100 parts by mass of the olefin component, and
A binder for paint, wherein the amount of unsaturated carboxylic acid monomer in the dry residue of the binder for paint is 10,000 ppm or less.
(2) The binder for paints according to (1), which does not substantially contain a non-volatile aqueous agent.
(3) The paint binder according to (1) or (2), wherein the polyolefin resin has a weight average particle diameter of 0.15 μm or less.
(4) A paint comprising the paint binder according to any one of (1) to (3) above.
(5) A coating film obtained from the paint described in (4) above.

The binder for paints of the present invention is excellent in mixing stability with other paint materials such as pigments and inorganic particles, and is suitable as a binder for various paints.
The paint containing the binder for paint of the present invention has excellent adhesion to a cycloolefin polymer base material in addition to the conventional polyolefin resin base material, and has a very high industrial utility value. . Moreover, the coating material containing the binder for coating materials of the present invention suppresses fading when used outdoors for a long period of time, and is excellent in light resistance. Furthermore, the paint containing the binder for paint of the present invention is excellent in adhesion and water resistance during low-temperature baking.

Hereinafter, the present invention will be described in detail.
The binder for paints of the present invention comprises a polyolefin resin and an aqueous medium.

First, the polyolefin resin will be described.
The polyolefin resin in the present invention contains an olefin component and an unsaturated carboxylic acid component as copolymerization components.
The olefin component needs to contain propylene and butene (1-butene, isobutene, etc.). When other olefins are contained as the olefin component, the resulting coating material is a cycloolefin polymer substrate (hereinafter referred to as COP). It may be inferior in adhesion to a base material made of polypropylene (which may be referred to as a base material made of polypropylene) and inferior in adhesiveness at low temperature baking to a base material made of polypropylene (hereinafter sometimes referred to as a base material made of PP). There is.
In the present invention, the mass ratio of propylene to butene (propylene / butene) improves the adhesion of the coating film to the PP substrate or COP substrate in terms of reducing the dispersed particle diameter of the polyolefin resin particles. From the viewpoint, it is necessary to be 60/40 to 95/5, and preferably 60/40 to 80/20. When the proportion of propylene is less than 60% by mass, the adhesion to a PP substrate or a COP substrate is lowered. On the other hand, when it exceeds 95% by mass, the dispersed particle diameter of the polyolefin resin particles increases, and the resin It may be difficult to disperse in water.

  In the polyolefin resin, the copolymerization form of propylene and butene is not limited, and examples thereof include random copolymerization, block copolymerization, and graft copolymerization. From the viewpoint of ease of polymerization, the copolymerization may be random copolymerization. preferable.

  The polyolefin resin in this invention is resin which contains the said olefin component and unsaturated carboxylic acid component as a copolymerization component. From the viewpoint of dispersibility in an aqueous medium, the content of the unsaturated carboxylic acid component as the copolymerization component needs to be 1 part by mass or more with respect to 100 parts by mass of the olefin component composed of propylene and butene. 1 to 15 parts by mass, more preferably 1 to 10 parts by mass, still more preferably 1 to 8 parts by mass, and particularly preferably 1 to 7 parts by mass. Most preferably, it is 5-7 mass parts. When the content of the unsaturated carboxylic acid component is less than 1 part by mass, it becomes difficult to make the polyolefin resin water-based. On the other hand, when the content exceeds 15 parts by mass, it becomes easy to make the resin aqueous. Adhesion to a PP substrate or a COP substrate may be reduced.

As unsaturated carboxylic acid components, acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, aconitic acid, aconitic anhydride, fumaric acid, crotonic acid, citraconic acid, mesaconic acid, allyl succinic acid, etc. In addition, compounds having at least one carboxyl group or acid anhydride group in the molecule (in the monomer unit), such as unsaturated dicarboxylic acid half esters and half amides, can also be used. Among these, maleic anhydride, acrylic acid, and methacrylic acid are preferable, and maleic anhydride is more preferable from the viewpoint of easy introduction into a polyolefin resin containing propylene and butene (hereinafter referred to as an unmodified polyolefin resin). .
Therefore, in the present invention, it is preferable to use a propylene / butene / maleic anhydride terpolymer as the polyolefin resin.

The unsaturated carboxylic acid component may be copolymerized in the polyolefin resin, and its form is not limited. Examples thereof include random copolymerization, block copolymerization, and graft copolymerization.
In addition, the acid anhydride component introduced into the polyolefin resin tends to take an acid anhydride structure in a dry state, and a part or all of the ring is opened in an aqueous medium containing a basic compound described later, and the carboxylic acid or It tends to be its salt.

The method for introducing the unsaturated carboxylic acid component into the unmodified polyolefin resin is not particularly limited. For example, in the presence of a radical generator, the unmodified polyolefin resin and the unsaturated carboxylic acid component are heated above the melting point of the unmodified polyolefin resin. A method of melting and reacting, or a method in which an unmodified polyolefin resin and an unsaturated carboxylic acid component are dissolved in an organic solvent and then heated and stirred in the presence of a radical generator to react with the unmodified polyolefin resin. Examples thereof include a method of graft copolymerizing an unsaturated carboxylic acid component.
Examples of the radical generator used for graft copolymerization include di-tert-butyl peroxide, dicumyl peroxide, tert-butyl hydroperoxide, tert-butyl cumyl peroxide, benzoyl peroxide, dilauryl peroxide, Examples thereof include organic peroxides such as cumene hydroperoxide, tert-butyl peroxybenzoate, ethyl ethyl ketone peroxide, and di-tert-butyl diperphthalate, and azo compounds such as azobisisobutyronitrile. These may be appropriately selected and used depending on the reaction temperature.

The polyolefin resin in the present invention may contain other components other than those described above as necessary. Other components include (meth) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, and butyl (meth) acrylate, maleic acid such as dimethyl maleate, diethyl maleate, and dibutyl maleate. Acid esters, (meth) acrylic amides, alkyl vinyl ethers such as methyl vinyl ether and ethyl vinyl ether, vinyl esters such as vinyl formate, vinyl acetate, vinyl propionate, vinyl pivalate, vinyl versatate and vinyl esters Vinyl alcohol, 2-hydroxyethyl acrylate, glycidyl (meth) acrylate, (meth) acrylonitrile, styrene, substituted styrene, vinyl halides, vinylidene halides, carbon monoxide, Diacid Sulfur and the like, may be a mixture thereof.
In general, the content of these other components is preferably 10% by mass or less of the polyolefin resin.

  In the present invention, a commercially available polyolefin resin may be used. For example, Sumitomo Chemical's Tough Selenium Series, Mitsui Chemicals' Toughmer Series, REXtac's APAO Series (Amorphous Polyalphaolefin), Clariant's Ricocene PP Series, Evonik Degussa's Best For example, plast. Further, as the polyolefin resin, a commercially available unmodified polyolefin resin obtained by introducing an unsaturated carboxylic acid component by a known method may be used.

As will be described later, the amount of unsaturated carboxylic acid monomer in the dry residue is required to be 10,000 ppm or less in the coating material binder of the present invention.
According to the present inventors, the amount of unsaturated carboxylic acid monomer in the dry residue of the aqueous dispersion containing only the polyolefin resin as a solid component coincides with the amount of unsaturated carboxylic acid monomer measured with the polyolefin resin raw material before the aqueousization. It has been confirmed that
In the present invention, it is preferable to use a polyolefin resin having an unsaturated carboxylic acid monomer amount of 10,000 ppm or less, more preferably an unsaturated carboxylic acid monomer amount of 5,000 ppm or less, More preferably, it is 000 ppm or less, particularly preferably 500 ppm or less, and most preferably 100 ppm or less.

Usually, when an unsaturated carboxylic acid component is introduced into an unmodified polyolefin resin by the method as described above, an unreacted unsaturated carboxylic acid monomer remains in the polyolefin resin.
The method for reducing the unsaturated carboxylic acid monomer in the polyolefin resin is not particularly limited. For example, a method for distilling the polyolefin resin under reduced pressure, a method for separating the polyolefin resin by dissolving it in a solvent and reprecipitation, a powder or Examples thereof include a method of washing the pelletized polyolefin resin in water or an organic solvent, a method of removing by a Soxhlet extraction method, and the like. Among them, from the viewpoints of operability and reduction efficiency, a method of distilling from a polyolefin resin under reduced pressure, a method of separating a polyolefin resin by dissolving it in a solvent and reprecipitation, a polyolefin resin made into a powder or pellet form with water or an organic solvent The method of washing in is preferred.

  As a method for quantifying the unsaturated carboxylic acid monomer in the polyolefin resin, a known method can be used. As an example, an unsaturated carboxylic acid monomer can be extracted from a resin with an extraction solvent and quantified using liquid chromatography, gas chromatography, or the like. Moreover, when quantifying the acid anhydride of an unsaturated carboxylic acid monomer, you may quantify as a corresponding unsaturated carboxylic acid monomer by hydrolyzing with water.

  The polyolefin resin in the present invention preferably has a weight average molecular weight of 5,000 to 200,000, more preferably 10,000 to 150,000, and more preferably 20,000 to 120,000. More preferably, it is particularly preferably 30,000 to 100,000, and most preferably 35,000 to 80,000. When the weight average molecular weight of the polyolefin resin is less than 5,000, the adhesion with the substrate tends to be reduced, or the resulting coating film tends to be brittle, whereas, when the weight average molecular weight exceeds 200,000, It tends to be difficult to make the resin water-based. In addition, the weight average molecular weight of resin can be calculated | required on the basis of polystyrene resin using a gel permeation chromatography (GPC).

  The paint binder of the present invention contains the above-described polyolefin resin and an aqueous medium, and the polyolefin resin is dispersed or dissolved in the aqueous medium. In this invention, an aqueous medium is a liquid which has water as a main component, and may contain the basic compound and organic solvent which are mentioned later.

  Basic compounds include ammonia, triethylamine, N, N-dimethylethanolamine, isopropylamine, aminoethanol, dimethylaminoethanol, diethylaminoethanol, ethylamine, diethylamine, isobutylamine, dipropylamine, 3-ethoxypropylamine, 3- Diethylaminopropylamine, sec-butylamine, propylamine, n-butylamine, 2-methoxyethylamine, 3-methoxypropylamine, 2,2-dimethoxyethylamine, monoethanolamine, morpholine, N-methylmorpholine, N-ethylmorpholine, pyrrole , Pyridine and the like. The content of the basic compound is preferably 0.5 to 10 times equivalent, more preferably 0.8 to 5 times equivalent, and 0.9 to 3.0 times equivalent to the carboxyl group in the polyolefin resin. Is particularly preferred. If the amount is less than 0.5 times equivalent, the effect of adding a basic compound is not recognized, and if the amount exceeds 10 times equivalent, the drying time during coating formation may be prolonged, or the stability of the aqueous dispersion may be reduced. is there.

In the present invention, it is preferable to add a hydrophilic organic solvent at the time of aqueous formation in order to promote aqueousization of the polyolefin resin and reduce the dispersed particle size. The content of the hydrophilic organic solvent is preferably 50% by mass or less, more preferably 1 to 45% by mass, still more preferably 2 to 40% by mass, and particularly preferably 3 to 35% by mass with respect to the entire aqueous medium. preferable. When the content of the hydrophilic organic solvent exceeds 50% by mass, the hydrophilic organic solvent cannot be regarded as an aqueous medium substantially and does not deviate from one of the objects of the present invention (environmental protection). Depending on the case, the stability of the aqueous dispersion may decrease.
As the hydrophilic organic solvent, from the viewpoint of obtaining an aqueous dispersion having good dispersion stability, the solubility in water at 20 ° C. is preferably 10 g / L or more, more preferably 20 g / L or more, and more preferably 50 g / L. More than L is more preferable.
As the hydrophilic organic solvent, those having a boiling point of 150 ° C. or less are preferable from the viewpoint of efficiently removing them from the coating film in the course of film formation. A hydrophilic organic solvent having a boiling point exceeding 150 ° C. tends to be difficult to scatter from the coating film by drying, and particularly, the water resistance of the coating film at low temperature drying and the adhesion to the substrate decrease. There is.

Preferred hydrophilic organic solvents include, for example, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, n-amyl alcohol, isoamyl alcohol, sec-amyl alcohol, tert- Alcohols such as amyl alcohol, 1-ethyl-1-propanol, 2-methyl-1-butanol, n-hexanol, cyclohexanol, ketones such as methyl ethyl ketone, methyl isobutyl ketone, ethyl butyl ketone, cyclohexanone, tetrahydrofuran, dioxane, etc. Ethers, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, sec-butyl acetate, 3-methoxybutyl acetate, propion Esters such as methyl, ethyl propionate, diethyl carbonate, dimethyl carbonate, glycol derivatives such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol ethyl ether acetate, and 1-methoxy-2-propanol, 1-ethoxy-2-propanol, 3-methoxy-3-methyl-1-butanol, methoxybutanol, acetonitrile, dimethylformamide, dimethylacetamide, diacetone alcohol, ethyl acetoacetate, 1, Examples include 2-dimethyl glycerin, 1,3-dimethyl glycerin, and trimethyl glycerin.
Among them, ethanol, n-propanol, isopropanol, n-butanol, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, dioxane, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, and diethylene glycol monomethyl ether promote the aqueousization of polyolefin resins. More effective and preferable.
In the present invention, a plurality of these hydrophilic organic solvents may be mixed and used.

  In order to further promote the aqueous formation of the polyolefin resin, a hydrophobic organic solvent may be further added. As the hydrophobic organic solvent, a hydrophobic organic solvent having a solubility in water at 20 ° C. of less than 10 g / L and having a boiling point of 150 ° C. or lower is preferable for the same reason as described above. Examples of the hydrophobic organic solvent include olefin solvents such as n-pentane, n-hexane, n-heptane, cycloheptane, cyclohexane and petroleum ether, aromatic solvents such as benzene, toluene and xylene, Examples thereof include halogenated solvents such as carbon chloride, 1,2-dichloroethane, 1,1-dichloroethylene, trichloroethylene, 1,1,1-trichloroethane, and chloroform. The addition amount of these hydrophobic organic solvents is preferably 15% by mass or less, more preferably 10% by mass or less, and further preferably 5% by mass or less with respect to the aqueous dispersion. When the addition amount exceeds 15% by mass, gelation or the like may be caused.

  The particle diameter of the polyolefin resin particles dispersed in the paint binder of the present invention is not particularly limited, but from the viewpoint of low-temperature film-forming properties, denseness and transparency of the coating film, and mixing stability with other materials, The weight average particle diameter is preferably 0.15 μm or less, more preferably 0.10 μm or less, further preferably 0.05 μm or less, and particularly preferably 0.001 to 0.05 μm. . When the weight average particle diameter exceeds 0.15 μm, the adhesion at low temperature baking of the coating film may be inferior.

  In the present invention, the degree of dispersion (weight average particle diameter / number average particle diameter) relating to the particle size distribution of the polyolefin resin in the coating binder is preferably 2.6 or less, and particularly the smoothness of the coating film. From the viewpoint, it is preferably 2.0 or less, more preferably 1.5 or less, and further preferably 1.3 or less. When the degree of dispersion exceeds 2.6, the smoothness and adhesion of the coating film tend to decrease.

  The zeta potential in the binder for paints of the present invention is preferably −20 mV or less, and more preferably −30 mV or less. When the zeta potential is −20 mV or less, the paint binder is excellent in dispersion stability, and also in mixing stability when mixed with various additives.

  In the present invention, the content of the polyolefin resin in the coating binder can be appropriately selected according to the film forming conditions, the thickness of the coating film, the performance, etc., and is not particularly limited, but the viscosity of the coating binder is appropriately set. It is preferably 1 to 60% by mass, more preferably 3 to 55% by mass, and further preferably 5 to 50% by mass in terms of maintaining and exhibiting good coating film forming ability. It is particularly preferably 10 to 45% by mass.

In the present invention, the amount of the unsaturated carboxylic acid monomer in the dry residue of the coating binder is required to be 10,000 ppm or less, preferably 5,000 ppm or less, more preferably 1,000 ppm or less. Preferably, it is 500 ppm or less, more preferably 100 ppm or less.
As described above, unreacted unsaturated carboxylic acid monomer remains in the polyolefin resin. When the amount of the unsaturated carboxylic acid monomer contained in the drying residue of the paint binder exceeds 10,000 ppm, the resulting paint binder may be inferior in water resistance and light resistance. In particular, from the viewpoint of improving light resistance, the amount of unsaturated carboxylic acid monomer contained in the dry residue of the binder for paint is more preferably 5,000 ppm or less.
As a method of quantifying the unsaturated carboxylic acid monomer in the coating material binder, a known method can be used. As an example, a dry residue obtained by removing the liquid medium of the binder for paint can be prepared and quantified by the same method as the method for quantifying the unsaturated carboxylic acid monomer in the polyolefin resin described above.

  It is preferable that the binder for coating materials of the present invention does not substantially contain a nonvolatile aqueous agent. Although it does not exclude the use of a non-volatile aqueous additive in the coating binder of the present invention, the polyolefin resin can be made aqueous by using the production method exemplified in the present invention without using an aqueous additive. It can be finely and stably dispersed in the medium. For this reason, the coating film characteristic in low temperature drying, especially water resistance, and adhesiveness with a base material are excellent, and these performances hardly change in the long term.

  Here, the “aqueous additive” is a chemical or a compound added for the purpose of promoting aqueous formation or stabilizing in the production of a binder for paint, and “nonvolatile” means normal pressure. It means that it does not have a boiling point or has a high boiling point (for example, 300 ° C. or higher) at normal pressure.

  “Substantially free of non-volatile water-based auxiliary” means that such an auxiliary is not used at the time of production (resin aqueous), and the resulting coating binder does not contain this auxiliary. Means. Therefore, it is particularly preferable that the content of such an aqueous auxiliary agent is zero, but within a range not impairing the effects of the present invention, it is 5% by mass or less, preferably 2% by mass or less, and further, Preferably, it may be contained less than about 0.5% by mass.

  Examples of the non-volatile auxiliary agent used in the present invention include an emulsifier described later, a compound having a protective colloid action, a modified wax, an acid-modified compound having a high acid value, and a water-soluble polymer.

  Examples of the emulsifier include a cationic emulsifier, an anionic emulsifier, a nonionic emulsifier, and an amphoteric emulsifier. In addition to those generally used for emulsion polymerization, surfactants are also included. For example, anionic emulsifiers include higher alcohol sulfates, higher alkyl sulfonates, higher carboxylates, alkyl benzene sulfonates, polyoxyethylene alkyl sulfate salts, polyoxyethylene alkyl phenyl ether sulfate salts, vinyl sulfosuccinates. Nonionic emulsifiers include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyethylene glycol fatty acid ester, ethylene oxide propylene oxide block copolymer, polyoxyethylene fatty acid amide, ethylene oxide-propylene oxide. Compounds having a polyoxyethylene structure such as copolymers and sorbitan derivatives such as polyoxyethylene sorbitan fatty acid esters And examples of the amphoteric emulsifiers, lauryl betaine, lauryl dimethyl amine oxide, and the like.

  Compounds having protective colloid action, modified waxes, acid-modified compounds with high acid value, water-soluble polymers include polyvinyl alcohol, carboxyl group-modified polyvinyl alcohol, carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, modified starch, polyvinylpyrrolidone Polyacrylic acid and salts thereof, carboxyl group-containing polyethylene wax, carboxyl group-containing polypropylene wax, carboxyl group-containing polyethylene-propylene wax, and other acid-modified polyolefin waxes having a number average molecular weight of usually 5000 or less and salts thereof, acrylic acid-anhydride Maleic acid copolymer and salt thereof, styrene- (meth) acrylic acid copolymer, ethylene- (meth) acrylic acid copolymer, isobutylene-maleic anhydride A carboxyl group-containing polymer having an unsaturated carboxylic acid content of 10% by mass or more, such as an acid alternating copolymer, a (meth) acrylic acid- (meth) acrylic acid ester copolymer, and a salt thereof, polyitaconic acid and a salt thereof, amino Examples thereof include water-soluble acrylic copolymers having a group, gelatin, gum arabic, and casein, and compounds generally used as fine particle dispersion stabilizers.

The manufacturing method of the binder for coating materials is demonstrated.
A method for obtaining the binder for coating used in the present invention is not particularly limited, but the above-described components, that is, a polyolefin resin, an aqueous medium, an organic solvent, a basic compound, and the like as required, can be sealed in a container. The method of heating and stirring can be employed, and this method is most preferred.

  As a container, the apparatus used as a solid / liquid stirring apparatus or an emulsifier can be used, It is preferable to use the apparatus which can pressurize 0.1 Mpa or more. The stirring method and the rotation speed of stirring are not particularly limited, but may be stirring at a low speed such that the polyolefin resin is in a floating state in an aqueous medium. Therefore, high-speed stirring (for example, 1000 rpm or more) is not essential, and a paint binder can be produced with a simple apparatus.

  For example, raw materials such as a polyolefin resin and an aqueous medium are charged into the above apparatus, and the mixture is preferably stirred and mixed at a temperature of 40 ° C. or lower. Next, while maintaining the temperature in the tank at 70 to 240 ° C., preferably 100 to 220 ° C., more preferably 100 to 200 ° C., particularly preferably 110 to 190 ° C., preferably until there are no coarse particles (for example, Continue stirring (5 to 300 minutes). Here, when the temperature in the tank is less than 70 ° C., it becomes difficult to make the polyolefin resin water-based. On the other hand, when the temperature in the tank exceeds 240 ° C., the molecular weight of the polyolefin resin may decrease.

In this method, a basic compound, an organic solvent, and water may be added as appropriate, and the ratio at that time may be appropriately determined according to the desired solid content concentration, particle size, degree of dispersion, and the like. The method of adding a basic compound, an organic solvent, or water is not particularly limited, but a method of using a gear pump to add under pressure, a method of lowering the system temperature to normal pressure, and opening and adding, etc. There is. The total amount of the basic compound, organic solvent or water to be added is preferably adjusted so that the solid content concentration after mixing is 1 to 50% by mass, more preferably 2 to 45% by mass, An amount of 3 to 40% by mass is particularly preferred.
Moreover, after additional mixing, it heats again to the temperature of 80-240 degreeC, and stirs.
Thus, the weight average particle diameter of polyolefin resin can be made small by adding what comprises an aqueous medium, and heating and stirring again. Thus, it is preferable to make the resin aqueous by a two-stage process in order to adjust the dispersity of the particle size distribution within a preferable range.
In the above process, when the temperature in the tank is less than 80 ° C., it becomes difficult for the polyolefin resin to become water-based. On the other hand, when the temperature in the tank exceeds 240 ° C., the molecular weight of the polyolefin resin may decrease. .

When the above organic solvent is used during the production of the coating binder, a part of the organic solvent is distilled out of the system by a solvent removal process generally called “stripping” after the resin is made aqueous. The content may be reduced. By stripping, the content of the organic solvent in the aqueous dispersion can be 10% by mass or less, more preferably 5% by mass or less, and more preferably 1% by mass or less. In the stripping process, it is possible to distill off substantially all of the organic solvent used to make the aqueous solution, but it is necessary to increase the degree of vacuum of the equipment and lengthen the operation time. In consideration, the lower limit of the organic solvent content is preferably about 0.01% by mass.
Examples of the stripping method include a method in which the aqueous dispersion is heated with stirring at normal pressure or reduced pressure to distill off the organic solvent. In addition, since the solid content concentration is increased by distilling off the aqueous medium, for example, when the viscosity increases and workability decreases, water is added to the paint binder in advance. Also good.

  The solid content concentration of the paint binder can be adjusted by, for example, a method of distilling off the aqueous medium or a method of diluting with water.

  By adopting the above production method, it is possible to prepare a uniform liquid coating material binder in which a polyolefin resin is efficiently dispersed or dissolved in an aqueous medium. Here, the uniform liquid state means that the portion where the solid content concentration is locally different from other portions, such as precipitation, phase separation or skinning, is not found in the coating binder. Say.

  In order to further improve the performance according to the purpose, other polymers, tackifiers, crosslinking agents, and the like can be added to the paint binder of the present invention.

  In the present invention, other polymers and tackifiers added to the paint binder are not particularly limited. For example, polyvinyl acetate, ethylene-vinyl acetate copolymer, polyvinyl chloride, polyvinylidene chloride, ethylene- (meth) acrylic acid copolymer, ethylene- (meth) acrylic acid ester-maleic anhydride copolymer, styrene -Maleic acid resin, styrene-butadiene resin, butadiene resin, acrylonitrile-butadiene resin, polyurethane resin, poly (meth) acrylonitrile resin, (meth) acrylamide resin, chlorinated polyethylene resin, chlorinated polypropylene resin, polyester resin, modified nylon resin , Polyurethane resins, rosin and other tackifying resins, phenol resins, silicone resins, epoxy resins and the like, and a plurality of them may be mixed and used as necessary. These polymers may be used in the form of a solid, but it is preferable to use a polymer processed into an aqueous dispersion from the viewpoint of maintaining the stability of the binder for coatings. Among these, it is preferable to add a polyurethane resin from the viewpoints of adhesion to a substrate, chemical resistance, and heat resistance.

As the polyurethane resin, a polymer containing a urethane bond in the main chain can be used. For example, a polymer obtained by a reaction between a polyol compound and a polyisocyanate compound can be used.
The polyol component constituting the polyurethane resin is not particularly limited. For example, water, ethylene glycol, diethylene glycol, triethylene glycol, 1,3-butanediol, 1,4-butanediol, 1,2-propanediol, 1 , 3-propanediol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, methyl-1,5-pentanediol, 1,8-octanediol, 2-ethyl-1,3-hexane Low molecular weight glycols such as diol, diethylene glycol, triethylene glycol, and dipropylene glycol; low molecular weight polyols such as trimethylolpropane, glycerin, and pentaerythritol; and polyols having ethylene oxide and propylene oxide units. Le compounds, polyether diols, high molecular weight diols such as polyester diols, bisphenols such as bisphenol A, bisphenol F, dimer diol, and the like to the carboxyl group of the dimer acid was converted to hydroxyl groups.
Moreover, as a polyisocyanate component which comprises a polyurethane resin, the 1 type, or 2 or more types of mixture of well-known diisocyanate which belongs to aromatic, aliphatic, or alicyclic can be used. Specific examples of diisocyanates include tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,3-phenylene diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, 1,5-naphthalene diisocyanate, isophorone diisocyanate, dimethyl diisocyanate, lysine diisocyanate. Hydrogenated 4,4′-diphenylmethane diisocyanate, hydrogenated tolylene diisocyanate, dimerized isocyanate obtained by converting the carboxyl group of dimer acid to an isocyanate group, and adducts, biurets, and isocyanurates. As the diisocyanates, trifunctional or higher functional polyisocyanates such as triphenylmethane triisocyanate and polymethylene polyphenyl isocyanate may be used.
In this invention, a commercially available thing can be used as a water-based polyurethane resin suitable for adding to the binder for coating materials. Examples of commercially available water-based polyurethane resins include Takelac series (W-615, W-6010, W-511, etc.) manufactured by Mitsui Chemicals, Adekabon titer series (HUX-232, HUX-320, HUX- manufactured by Adeka). 380, HUX-401, etc.), Daiichi Kogyo Seiyaku Co., Ltd. Superflex series (500, 550, 610, 650, etc.), Dainippon Ink & Chemicals Hydran series (HW-311, HW-350, HW- 150) and the like.

As a crosslinking agent to be added to a coating binder, a crosslinking agent having a self-crosslinking property, a compound having a plurality of functional groups that react with an unsaturated carboxylic acid component in the molecule, a metal having a polyvalent coordination site, or the like is used. Can do.
Specific examples include isocyanate compounds, melamine compounds, urea compounds, epoxy compounds, carbodiimide compounds, oxazoline group-containing compounds, zirconium salt compounds, silane coupling agents, etc. Also good. Among them, it is preferable to add an oxazoline group-containing compound from the viewpoint of ease of handling. As the oxazoline group-containing compound, those having two or more oxazoline groups in the molecule can be preferably used. For example, 2,2'-bis (2-oxazoline), 2,2'-ethylene-bis (4,4'-dimethyl-2-oxazoline), 2,2'-p-phenylene-bis (2-oxazoline) , A compound having an oxazoline group such as bis (2-oxazolinylcyclohexane) sulfide, an oxazoline group-containing polymer, and the like. These 1 type (s) or 2 or more types can be used. Among these, an oxazoline group-containing polymer is preferable because it is easy to handle.
The oxazoline group-containing polymer is generally obtained by polymerizing an addition polymerizable oxazoline such as 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline. The oxazoline group-containing polymer may be copolymerized with other monomers as necessary. The polymerization method of the oxazoline group-containing polymer is not particularly limited, and a known polymerization method can be employed.
Examples of commercially available oxazoline group-containing polymers include EPOCROSS series manufactured by Nippon Shokubai Co., Ltd., for example, water-soluble type “WS-500”, “WS-700”; emulsion type “K-1010E”, “ K-1020E "," K-1030E "," K-2010E "," K-2020E "," K-2030E "and the like.
The addition amount of the crosslinking agent is preferably 0.01 to 80 parts by mass with respect to 100 parts by mass of the polyolefin resin from the viewpoint of improving the water resistance and solvent resistance of the coating film, and 0.1 to 50 parts by mass. More preferably, it is 0.5-30 mass parts. When the addition amount of the crosslinking agent is less than 0.01 parts by mass, the coating film performance may not be sufficiently improved, and when it exceeds 80 parts by mass, the workability may be deteriorated.

  Various agents such as leveling agents, antifoaming agents, anti-waxing agents, pigment dispersants, UV absorbers, thickeners, weathering agents, flame retardants, etc. can be added to the paint binder as needed. It is.

The paint can be easily obtained by mixing the binder for paint of the present invention with various paint materials.
By using the binder for paints of the present invention, a paint that adheres well to the base material without any pre-treatment or primer treatment on the base material, and particularly has excellent adhesion to a PP base material or a COP base material. Can be obtained. The coating film obtained from the paint is excellent in adhesion and water resistance during low-temperature baking.

  As paint components other than the binder for paint constituting the paint of the present invention, components used in general paints can be contained. Examples of such components include, in addition to coloring materials such as pigments and dyes, inorganic particles, leveling agents, antifoaming agents, anti-waxing agents, pigment dispersants, ultraviolet absorbers, thickeners, weathering agents, flame retardants. And various additives such as preservatives and surface tension modifiers.

  As the coloring material, a known coloring material can be used. For example, zinc white, lead white, lithopone, titanium dioxide, precipitated barium sulfate, red lead, iron oxide red, cinnabar, yellow lead, zinc yellow type 1, zinc 2 types of yellow, ocher, cobalt yellow, yellow complex oxide pigment, titanium yellow, vanadium zirconium yellow, vanadium tin yellow, bismuth vanadium yellow, praseodymium yellow, cadmium yellow, ultramarine blue, prussian blue, agate, rock group blue, blue Complex oxide pigment, cobalt pigment, manganese blue, green clay, rock patina, verdegli, fan ake green, chelé green, emerald green, cobalt green pigment, chrome green pigment, iron oxide purple, purple ultramarine blue, manganese purple, cobalt Inorganic pigments such as purple and carbon black, monoazo, disazo, condensed disazo, quinacridone, perylene, diketopyrrolo pillow , Anthraquinone, pyrazolone, benzimidazolone, quinoxaline, azomethine, quinophthalone, isoindolinone, isoindoline, metal complex, indigo, phthalocyanine, and other organic pigments, aluminum powder, bronze powder Metallic pigments such as gold powder, silver powder, copper powder, stainless steel powder and nickel powder, pearl pigments and dyes can be used. Moreover, you may use the dispersion liquid which melt | dissolved or disperse | distributed the said coloring material in arbitrary liquid media.

  Examples of the inorganic particles include metal oxides such as magnesium oxide, zinc oxide and tin oxide, inorganic particles such as calcium carbonate and silica, and layered inorganic compounds such as vermiculite, montmorillonite, hectorite, hydrotalcite and synthetic mica. It is done. The average particle diameter of these inorganic particles is preferably 0.005 to 10 μm, and more preferably 0.005 to 5 μm from the viewpoint of mixing stability. A plurality of inorganic particles may be mixed and used. Zinc oxide can be used for ultraviolet shielding, and tin oxide can be used for antistatic purposes.

  A known method can be used as a method for producing a paint composed of the above components. As an example, a method for dispersing a pigment is illustrated. First, a color material is added to an aqueous medium in which a color material dispersant and water are mixed, mixed and stirred, and then dispersed using a disperser such as a sand mill. And performing a centrifugal separation process as necessary to obtain a desired colorant dispersion. Next, the colorant dispersion and the coating material binder of the present invention are mixed and stirred, and if necessary, a water-soluble solvent or additives as mentioned above are added to form a coating material. Moreover, you may filter as needed.

Since the binder for paints of the present invention is excellent in adhesion to polypropylene and cycloolefin polymers, the substrate to which the paint of the present invention is applied is preferably made of a polyolefin resin such as polypropylene or cycloolefin polymers.
Examples of the cycloolefin polymer include cyclic rings in the main chain described in JP-A-10-120768, JP-A-11-43566, JP-A-2004-51949, JP-A-2004-156048, and the like. A thermoplastic olefin resin having an olefin skeleton may be mentioned. Examples of commercially available cycloolefin polymers include ARTON manufactured by JSR, ZEONOR and ZEONEX manufactured by Nippon Zeon, TOPAS manufactured by Polyplastics, and APEL manufactured by Mitsui Chemicals.

As the base material to which the paint of the present invention is applied, thermoplastic resins other than polyolefin resins and their films, metals and metal foils, paper, and the like can also be used.
Examples of thermoplastic resins other than polyolefin resins include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, and mixtures thereof; polycapronamide (nylon 6), polyhexamethylene adipamide (Nylon 66), poly-p-xylylene adipamide (MXD nylon), and polyamide resins such as mixtures thereof; polyolefin resins such as polyethylene, polypropylene, and mixtures thereof; polyvinyl chloride; polyvinyl alcohol; ethylene Examples thereof include random copolymers of vinyl alcohol.

As a method for applying the paint of the present invention, known methods such as spray coating, dip coating, brushing, gravure printing, offset printing, flexographic printing, screen printing, octopus printing, inkjet printing, gravure roll coating, Reverse roll coating, wire bar coating, lip coating, air knife coating, curtain flow coating, etc. can be employed.
The coating amount of the paint is appropriately selected depending on the application, and is preferably 0.01 to 100 μm, more preferably 0.1 to 70 μm, and further preferably 1 to 50 μm as a dry film thickness. If the film is formed so that the coating amount after drying is 0.01 to 100 μm, a coating film having excellent uniformity can be obtained.
In addition, in order to obtain a uniform coating film, it is preferable to use a paint whose concentration and viscosity are adjusted according to the apparatus and use conditions, in addition to appropriately selecting the apparatus used for application and use conditions thereof. .

As a heating device for drying and baking, a normal hot air circulation type oven, an infrared heater, or the like can be used.
The heating temperature and the heating time are appropriately selected depending on the characteristics of the substrate as an object to be coated and the addition amounts of the various materials described above that can be arbitrarily blended in the paint. As heating temperature, it is preferable that it is 10-250 degreeC, It is more preferable that it is 20-200 degreeC, It is further more preferable that it is 20-150 degreeC. On the other hand, the heating time is preferably 1 second to 60 minutes, more preferably 5 seconds to 40 minutes, and even more preferably 5 seconds to 30 minutes. In addition, when a crosslinking agent is included as an additive, the heating temperature and time depend on the type of the crosslinking agent in order to sufficiently advance the reaction between the polyolefin resin and other polymers, and the carboxyl group in the coloring material and the crosslinking agent. It is desirable to select appropriately.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.
Various characteristics were measured or evaluated by the following methods.

1. Polyolefin resin (1) Composition of resin other than unsaturated carboxylic acid component The mass ratio of propylene and butene was ¹ H-NMR, ¹³ C-NMR analysis (Varian) at 120 ° C. in orthodichlorobenzene (d ₄ ). Manufactured, 300 MHz). ^{In 13} C-NMR analysis, measurement was performed based on a gated decoupling method in consideration of quantitativeness.

(2) Unsaturated carboxylic acid component content The unsaturated carboxylic acid component content relative to the olefin component is determined by infrared absorption spectrum analysis (Perkin Elmer System-2000 Fourier transform infrared spectrophotometer, resolution 4 cm ^-1 ). It was.

(3) Unsaturated carboxylic acid monomer amount Weigh precisely about 0.05 g of a finely pulverized polyolefin resin pellet, and extract it at room temperature for 21 hours by continuous inversion mixing with 20 mL of methanol as the extraction solvent. It was. The filtrate obtained by filtering this extract with a disk filter (pore size: 0.45 μm) was subjected to high performance liquid chromatography (HP1100, manufactured by Hewlett Packard, column is Puresil 5 μm C18 120Å φ4.6 mm × 250 mm (40 ° C.) manufactured by Waters). Quantified.
When the amount of the unsaturated carboxylic acid monomer was less than 1000 ppm, the amount of polyolefin resin pellets was changed to 0.5 g, and the amount was similarly determined.
The calibration curve was prepared using an unsaturated carboxylic acid monomer standard sample with a known concentration.

(4) Weight average molecular weight The weight average molecular weight was measured using GPC analysis (HLC-8020 manufactured by Tosoh Corporation, and two KF-804L and one KF805L manufactured by SHODEX were connected to each other) and tetrahydrofuran was used as an eluent. The measurement was performed under the conditions of a flow rate of 1 mL / min and 40 ° C. About 10 mg of resin was dissolved in 5.5 mL of tetrahydrofuran and filtered through a PTFE membrane filter as a measurement sample. The weight average molecular weight was determined from a calibration curve prepared with a polystyrene standard sample. When it was difficult to dissolve in tetrahydrofuran, it was dissolved in orthodichlorobenzene.

2. Binder for paint
(1) Number average particle size, weight average particle size, and degree of dispersion of polyolefin resin particles Using a Nanotrac Wave-UZ152 particle size distribution measuring device manufactured by Nikkiso Co., Ltd., the number average particle size (mn), the weight average particle size (mw) ) Was measured. The refractive index of the resin was 1.5.
The degree of dispersion was calculated based on the following formula.
Dispersity = weight average particle diameter (mw) / number average particle diameter (mn)

(2) Viscosity The rotational dispersion (mPa · s) at a temperature of 20 ° C. was measured using a B-type viscometer (DVL-BII digital viscometer manufactured by Tokimec Co., Ltd.) for the aqueous dispersion after 300 mesh filtration.

(3) Amount of unsaturated carboxylic acid monomer in dry residue of paint binder By drying the paint binder, a dry residue as a solid content was obtained.
About 0.05 g of the residue obtained by freeze grinding and pulverizing the dried residue was precisely weighed, and 20 mL of ultrapure water was used as an extraction solvent, followed by extraction at room temperature for 20 hours by continuous inversion. The filtrate obtained by filtering this extract with a disk filter (pore size: 0.45 μm) was subjected to high performance liquid chromatography (HP1100, manufactured by Hewlett Packard, column is Puresil 5 μm C18 120Å φ4.6 mm × 250 mm (40 ° C.) manufactured by Waters). Quantified.
When the amount of unsaturated carboxylic acid monomer was less than 1000 ppm, the amount of the residue was changed to 0.5 g, and the amount was similarly determined.
The calibration curve was prepared using an unsaturated carboxylic acid monomer standard sample with a known concentration.

3. Paint (1) Stability The paint prepared by the method described below is allowed to stand at 40 ° C. for 30 days, the state of the paint is visually observed, filtered through a stainless steel filter (30 mesh, aperture 0.6 mm), Evaluation was made in three stages.
○: No aggregation or phase separation.
Δ: There is no phase separation, but there is a small amount of aggregate.
X: There are a large amount of aggregates or phase separation.

4). Coating (1) Adhesive The coating amount after drying on the PP molded piece (PP: Nippon Polypropylene, Novatec PP MA3) or COP molded piece (COP: Nippon Zeon, ZEONOR 1430R) Each sample was applied using a Mayer bar so as to have a thickness of about 10 μm, and dried at 120 ° C. for 30 minutes to obtain a coating film sample.
The coating film on the obtained molded piece was subjected to tape peeling (cross cut test) by the cross-cut method described in JIS K5400. That is, the coating film was cut into 100 sections by cross-cutting, and the adhesiveness was evaluated according to the following criteria by the number of coating film sections remaining after tape peeling.
A: 100 sections remaining.
○: 95 to 99 compartments remaining.
Δ: 90-94 compartments remaining.
X: Residue is 89 sections or less.

(2) Water resistance Each of the coating film samples prepared by the same method as in (1) was immersed in warm water at 40 ° C. for 24 hours.
With respect to the coating film on the molded piece, a cross-cut test was performed in the same manner as in (1) above, and water resistance was evaluated.
Moreover, the coating-film surface was observed visually and the external appearance was evaluated with the following parameters | indexes.
○: No change in coating film.
(Triangle | delta): Although a coating film has not peeled, whitening and a blister are confirmed.
X: The coating film is peeled off.

(3) Adhesiveness during low-temperature baking Application of the paint on a PP molded piece (PP: Nippon Polypropylene, Novatec PP MA3) or COP molded piece (COP: Nippon Zeon, ZEONOR 1430R) after drying Each was applied using a Mayer bar so that the amount was about 10 μm and dried at 90 ° C. for 30 minutes.
The coating film on the obtained PP molded piece and the coating film on the COP molded piece were evaluated in the same manner as in the above (1).

(4) Light resistance The coating film sample produced by the same method as in (1) above was radiated in accordance with ISO 787-15 using a xenon weather meter (Atlas Co., Ltd., Ci4000 type), with a black panel temperature of 50 ° C. and radiation. An irradiation test for 1000 hours was performed under the condition of an exposure amount of 550 W / m ² (no rain).
Here, based on JIS Z8722, using a spectral color difference meter (SE6000 manufactured by Nippon Denshoku Industries Co., Ltd.), the color difference ΔE of the coating film sample before and after the irradiation test is measured (light source: C-2), and the light resistance is measured. evaluated.
The color difference ΔE is practically preferably 5 or less, more preferably 3 or less.

Production Example 1: Polyolefin resin P-1
280 g of propylene-butene copolymer (mass ratio: propylene / 1-butene = 80/20) was dissolved in 470 g of xylene under a nitrogen atmosphere in a four-necked flask, and the system temperature was kept at 140 ° C. Under stirring, 40.0 g of maleic anhydride as an unsaturated carboxylic acid and 28.0 g of dicumyl peroxide as a radical generator were added over 2 hours, followed by reaction for 6 hours. After completion of the reaction, the obtained reaction product was put into a large amount of acetone to precipitate a resin.
The precipitated resin was washed once with an acetone solution of triethylamine (mass ratio: triethylamine / acetone = 1/4), and then washed with acetone to remove unreacted maleic anhydride, and then a vacuum dryer. Then, it was dried under reduced pressure to obtain polyolefin resin P-1.

Production Example 2: Polyolefin resin P-2
A polyolefin resin P-2 was obtained in the same manner as in Production Example 1 except that a propylene-butene copolymer having a mass ratio of propylene / 1-butene = 65/35 was used.

Production Example 3: Polyolefin resin P-3
In Production Example 1, a polyolefin resin P-3 was obtained in the same manner as described above except that the acetone washing step was omitted.

Production Example 4: Polyolefin resin P-4
A polyolefin resin P-4 was obtained in the same manner as in Production Example 1 except that the acetone solution of triethylamine was changed to acetone and the subsequent acetone washing was changed to methanol washing.

Production Example 5: Polyolefin resin P-5
After heating and dissolving 280 g of propylene-butene copolymer (mass ratio: propylene / 1-butene = 80/20) in 470 g of chlorobenzene under a nitrogen atmosphere in a four-necked flask, the system temperature was maintained at 130 ° C. Under stirring, 9.5 g of maleic anhydride as an unsaturated carboxylic acid and 10.0 g of dicumyl peroxide as a radical generator were added over 2 hours, respectively, and then reacted for 10 hours. After completion of the reaction, the obtained reaction product was put into a large amount of acetone to precipitate a resin and dried under reduced pressure in a vacuum dryer to obtain polyolefin resin P-5.

Production Example 6: Polyolefin resin P-6
In Production Example 1, the amount of maleic anhydride added was changed to 70.0 g instead of 40.0 g, the amount of dicumyl peroxide added was changed to 33.0 g instead of 28.0 g, and the washing step was washed twice with acetone. A polyolefin resin P-6 was obtained in the same manner as described above except for changing to.

Production Example 7: Polyolefin resin P-7
In Production Example 6, a polyolefin resin P-7 was obtained by performing the same operation except that the washing step was omitted.

Production Example 8: Polyolefin resin P-8
The same operation as in Production Example 1 was carried out except that the amount of maleic anhydride added was changed to 24.0 g instead of 40.0 g, and the amount of dicumyl peroxide added was changed to 18.5 g instead of 28.0 g. Thus, a polyolefin resin P-8 was obtained.

Production Example 9: Polyolefin resin P-9
In Production Example 1, the addition amount of maleic anhydride was changed to 70.0 g instead of 40.0 g, the addition amount of dicumyl peroxide was changed to 20.0 g instead of 28.0 g, and the washing step of the acetone solution of triethylamine and A polyolefin resin P-9 was obtained in the same manner as described above except that the acetone washing step was omitted.

Production Example 10: Polyolefin resin P-10
A polyolefin resin P-10 was obtained in the same manner as in Production Example 1, except that a propylene-butene copolymer having a mass ratio of propylene / 1-butene = 97/3 was used.

Production Example 11: Polyolefin resin P-11
A polyolefin resin P-11 was obtained in the same manner as in Production Example 1 except that a propylene-butene copolymer having a mass ratio of propylene / 1-butene = 50/50 was used.

Production Example 12: Polyolefin resin P-12
In Production Example 1, the same procedure was followed except that a propylene-ethylene copolymer (mass ratio: propylene / ethylene = 92/8) was used in place of the propylene-butene copolymer, and the polyolefin resin P- 12 was obtained.

Production Example 13: Polyolefin resin P-13
The same operation as in Production Example 1 except that a propylene-butene-ethylene copolymer (mass ratio: propylene / 1-butene / ethylene = 65/24/11) was used instead of the propylene-butene copolymer. And polyolefin resin P-13 was obtained.

Production Example 14: Polyolefin resin P-14
The same method as in Production Example 1 was carried out except that the amount of maleic anhydride added was changed to 2.0 g instead of 40.0 g, and the amount of dicumyl peroxide added was changed to 1.4 g instead of 28.0 g. Thus, a polyolefin resin P-14 was obtained.

  Table 1 shows the properties of the polyolefin resins obtained in Production Examples 1 to 14.

Example 1
Using a stirrer equipped with a 1 L glass container that can be sealed with a heater, 60.0 g polyolefin resin P-1, 99.0 g tetrahydrofuran, 11.6 g N, N-dimethylethanolamine (DMEA) and When 159.4 g of distilled water was charged into a glass container and stirred at a rotation speed of the stirring blade of 300 rpm, no resin precipitation was observed at the bottom of the container, confirming that it was in a floating state. Therefore, while maintaining this state, the heater was turned on and heated after 10 minutes. Then, the system temperature was maintained at 130 ° C. and further stirred for 60 minutes.
Then, after cooling to room temperature (about 25 ° C.) while stirring at an air-cooling speed of 300 rpm, 250 g of the aqueous dispersion and 120 g of distilled water were charged into a 0.5 L two-necked round bottom flask, A Liebig condenser was installed and the flask was heated in an oil bath to distill off the aqueous medium. When about 120 g of the aqueous medium was distilled off, heating was terminated and the mixture was cooled to room temperature. After cooling, the liquid component in the flask was subjected to pressure filtration (air pressure 0.2 MPa) with a 300-mesh stainless steel filter (wire diameter 0.035 mm, plain weave) to obtain a milky white uniform coating material binder E-1. At this time, almost no resin remained on the filter.
For the obtained binder for paint, various paints were prepared by the following method, the obtained paint was formed into a film, and the coating properties were evaluated.

(1) Magenta paint Pigment Red 122 as pigment, 30 g of polyolefin resin aqueous dispersion E-1 having a solid content of 40 g was predispersed with a disper and then filled with 1800 g of zirconia beads having a diameter of 0.5 mm and having a volume of 0.6 L Dispersion was performed for 2 hours using a dyno mill to obtain a pigment dispersion. To the pigment dispersion, 0.3 part by mass of proxel GXL (manufactured by Arch Chemicals), which is a preservative, is mixed with stirring with respect to 100 parts by mass of the solid content of the pigment dispersion, and the solid content concentration is 25 masses. % With purified water. A magenta paint was prepared by stirring until sufficiently uniform.

(2) Cyan paint A cyan paint was produced in the same manner as the magenta paint of (1) except that Pigment Blue 15: 3 was used instead of Pigment Red 122 as a pigment.

(3) White paint 30.0 g of titanium oxide (manufactured by Ishihara Sangyo Co., Ltd., CR-97) as a pigment, 1.5 g of SN Dispersant 5027 (manufactured by San Nopco) as a pigment dispersant, and FS Antifoam 013B (Dow) as an antifoaming agent Corning Co., Ltd.) 0.1 g of polyolefin resin aqueous dispersion E-1 having a solid content of 40 g was predispersed with a disper, and then 2 using a 0.6 L capacity dyno mill filled with 1800 g of zirconia beads having a diameter of 0.5 mm. Time dispersion was performed to obtain a pigment dispersion. 6 g of Texanol CS12 (manufactured by Chisso) as a film-forming aid and 0.4 g of SN thickener 612 (manufactured by San Nopco) as a thickener are mixed with the pigment dispersion while stirring, and the solid content is 25 mass. % With purified water. The mixture was stirred until it was sufficiently uniform to produce a white paint.

(4) Black paint An aqueous dispersion (Lion Paste W-376R, manufactured by Lion Corporation) and a polyolefin resin aqueous dispersion E-1 containing carbon black as a pigment are mixed with carbon black with respect to 100 parts by mass of the solid content of the polyolefin resin. Was blended so that the solid content would be 80 parts by mass to prepare a black paint.

Examples 2-8
It replaced with polyolefin resin P-1, and except having used the polyolefin resin of Table 2, operation similar to Example 1 was performed and the binders E-2 to E-8 for coating materials were obtained. In Examples 5 and 6, the amount of DMEA charged was 15.6 g. About the obtained binder for coating materials, the various coating materials were prepared by the method similar to Example 1, and the coating-film characteristic was evaluated.

Example 9
Using a stirrer equipped with a 1 L glass container that can be sealed with a heater, 60.0 g of polyolefin resin P-1, 99.0 g of tetrahydrofuran, 11.6 g of DMEA, and 159.4 g of distilled water were added to glass. When charged in the container and stirred at a rotational speed of the stirring blade of 300 rpm, no resin precipitation was observed at the bottom of the container, confirming that it was in a floating state. Therefore, while maintaining this state, the heater was turned on and heated after 10 minutes. Then, the system temperature was maintained at 130 ° C. and further stirred for 60 minutes.
And after cooling to room temperature (about 25 degreeC) stirring with air-cooling with the rotational speed of 300 rpm, the liquid component is pressure-filtered with a 300 mesh stainless steel filter (wire diameter 0.035 mm, plain weave) (pneumatic pressure 0. 2 MPa) to obtain a uniform white binder B-9 for paint. At this time, almost no resin remained on the filter.
About the obtained binder for coating materials, the various coating materials were prepared by the method similar to Example 1, and the coating-film characteristic was evaluated.

Example 10
60.0 g polyolefin resin P-1, 45.0 g ethylene glycol-n-butyl ether, 8.0 g DMEA and 137.0 g When distilled water was charged into a glass container and stirred at a rotation speed of 300 rpm, no resin precipitation was observed at the bottom of the container, confirming that it was in a floating state. Therefore, while maintaining this state, the heater was turned on and heated after 10 minutes. Then, the system temperature was kept at 160 ° C. and further stirred for 60 minutes.
Thereafter, it was cooled by air cooling until the internal temperature reached 80 ° C., opened, and 45.0 g of tetrahydrofuran, 5.0 g of DMEA and 30.0 g of distilled water were added. Thereafter, the mixture was sealed, and the stirring speed was 300 rpm, the system temperature was kept at 140 ° C., and the mixture was further stirred for 60 minutes.
Then, after cooling to room temperature (about 25 ° C.) while stirring at an air-cooling speed of 300 rpm, 250 g of the aqueous dispersion and 120 g of distilled water were charged into a 0.5 L two-necked round bottom flask, A Liebig condenser was installed and the flask was heated in an oil bath to distill off the aqueous medium. When about 120 g of the aqueous medium was distilled off, heating was terminated and the mixture was cooled to room temperature. After cooling, the liquid component in the flask was pressure filtered (air pressure 0.2 MPa) with a 300-mesh stainless steel filter (wire diameter 0.035 mm, plain weave) to obtain a milky white uniform coating material binder E-10. At this time, almost no resin remained on the filter.
About the obtained binder for coating materials, the various coating materials were prepared by the method similar to Example 1, and the coating-film characteristic was evaluated.

Comparative Examples 1-5
It replaced with polyolefin resin P-1, and except having used the polyolefin resin of Table 2, operation similar to Example 1 was performed and the binders E-11-E-15 for coating materials were obtained. In Comparative Example 1, the amount of DMEA charged was 15.6 g.
About the obtained binder for coating materials, the various coating materials were prepared by the method similar to Example 1, and the coating-film characteristic was evaluated.

Comparative Example 6
In Example 1, the same operation was performed except that P-14 was used in place of the polyolefin resin P-1, but it was difficult to make the polyolefin resin aqueous.

  Table 2 shows the properties of the coating binders obtained in Examples 1 to 10 and Comparative Examples 1 to 6. Moreover, the evaluation result of the coating material prepared using the obtained binder for coating materials is shown to Tables 3-6.

  As shown in Tables 3 to 6, the paints comprising the binder for paints of the present invention obtained in Examples 1 to 10 are excellent in paint stability when mixed with pigments, and the coating film is PP. It was excellent in adhesion, water resistance, adhesion at low temperature baking, and light resistance to the substrate made of COP and the substrate made of COP.

On the other hand, when the amount of the unsaturated carboxylic acid monomer contained in the coating binder exceeded the range specified in the present invention (Comparative Example 1), the resulting coating film was inferior in water resistance and light resistance.
The paint binder in which the mass ratio of propylene and butene (propylene / butene) constituting the polyolefin resin is outside the range defined in the present invention (Comparative Examples 2 and 3) is paint stability when a pigment is mixed. It was inferior to adhesiveness to the base material made from PP and the base material made from COP.
The binder for coating materials whose composition of the polyolefin resin is not defined in the present invention (Comparative Examples 4 and 5) is inferior in adhesion to the COP base material, and is also baked at low temperature on the PP base material. In some cases, the adhesion was poor.
Moreover, when there was less content of the unsaturated carboxylic acid component which comprises polyolefin resin than the range prescribed | regulated by this invention (comparative example 6), it was difficult to waterize polyolefin resin.

Claims (5)

A binder for a paint containing a polyolefin resin and an aqueous medium,
The polyolefin resin contains an olefin component and an unsaturated carboxylic acid component as a copolymer component,
The olefin component consists of propylene and butene,
The mass ratio of propylene to butene (propylene / butene) is 60/40 to 95/5,
The content of the unsaturated carboxylic acid component as the copolymer component is 1 part by mass or more with respect to 100 parts by mass of the olefin component, and
A binder for paint, wherein the amount of unsaturated carboxylic acid monomer in the dry residue of the binder for paint is 10,000 ppm or less.   The binder for paints according to claim 1, which is substantially free of non-volatile aqueous additive.   The binder for paint according to claim 1 or 2, wherein the polyolefin resin has a weight average particle diameter of 0.15 µm or less.   A paint comprising the binder for paint according to any one of claims 1 to 3. The coating film obtained from the coating material of Claim 4.