JP7680832B2 - Water dispersion composition and its uses - Google Patents

Description

The present invention relates to an aqueous dispersion composition and its uses.

Aqueous modified polyolefin resins modified with unsaturated carboxylic acids and/or their anhydrides are used as pretreatment agents for painting polyolefin resin substrates, which are poorly adherent substrates, or as adhesives (see, for example, Patent Document 1).

JP 2017-160375 A

However, when a conventional water-based resin is applied to a substrate as a primer, dried at low temperature (preheated), and then a water-based topcoat is applied, lifting (lifting of the coating film) may occur, and an improvement was required. The object of the present invention is to provide an aqueous dispersion composition that has good film-forming properties even under low-temperature drying conditions and can exhibit excellent adhesion and water resistance to poorly adhesive substrates such as polyolefin resin substrates.

The present invention provides the following [1] to [10].
[1] Component (A): a modified polyolefin resin in which at least one selected from an α,β-unsaturated carboxylic acid or an anhydride thereof is grafted onto a polyolefin resin;
Component (B): An aqueous dispersion composition containing at least a compound having a boiling point of 180° C. or higher and a solubility in water of 1.0 or lower, the compound being at least one selected from the group consisting of ethylene glycol 2-ethylhexyl ether, ethylene glycol monohexyl ether, 2-ethylhexanol, α-terpineol, 1-octanol, lauryl alcohol, cetyl alcohol, stearyl alcohol, oleyl alcohol, diethylene glycol dibutyl ether, and diethylene glycol mono 2-ethylhexyl ether, and preferably ethylene glycol 2- ethylhexyl ether, ethylene glycol monohexyl ether, and 2-ethylhexanol.
[2] The aqueous dispersion composition according to [1], wherein the content of component (B) is 0.01 to 10% by weight.
[3] The aqueous dispersion composition according to [1] or [2], wherein the polyolefin resin is one or more polyolefin resins selected from the group consisting of polypropylene, a propylene-butene copolymer, an ethylene-propylene copolymer, and an ethylene-propylene-butene copolymer.
[4] The aqueous dispersion composition according to any one of [1] to [3], wherein the weight average molecular weight of the modified polyolefin resin is 10,000 to 250,000.
[5] Component (C): The aqueous dispersion composition according to any one of [1] to [4], further comprising at least one compound having a boiling point of less than 180° C. and a solubility in water of more than 1.0, the compound being selected from the group consisting of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monoisobutyl ether, ethylene glycol mono-t-butyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, and 3-methyl-3-methoxybutanol.
[6] The aqueous dispersion composition according to any one of [1] to [5], wherein the content of component (C) is 0.01 to 10% by weight.
[7] A primer comprising the aqueous dispersion composition according to any one of [1] to [6].
[8] An adhesive comprising the aqueous dispersion composition according to any one of [1] to [6].
[9] A paint binder comprising the aqueous dispersion composition according to any one of [1] to [6].
[10] An ink binder comprising the aqueous dispersion composition according to any one of [1] to [6].

The present invention provides an aqueous dispersion composition that has good film-forming properties even under low-temperature drying conditions and exhibits excellent adhesion and water resistance to poorly adhesive substrates such as polyolefin resin substrates.

[(A) Modified polyolefin resin]
Component (A) is a modified polyolefin resin, which is a resin in which at least one selected from an α,β-unsaturated carboxylic acid and an anhydride thereof is grafted onto a polyolefin resin.

(Polyolefin resin)
Polyolefin resins are generally polymers containing olefin (α-olefin) structural units. In this specification, the term "olefin structural unit" refers to a structural unit derived from an olefin (α-olefin). Examples of α-olefins include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, styrene, and norbornene.

The polyolefin resin may be a single olefin polymer or a copolymer of two or more olefin polymers. When the polyolefin resin is a copolymer, the polyolefin resin may be a random copolymer or a block copolymer.

The polyolefin resin is preferably polypropylene (propylene homopolymer), ethylene-propylene copolymer, propylene-1-butene copolymer, or ethylene-propylene-1-butene copolymer, from the viewpoint of being able to exhibit sufficient adhesion to non-polar resin substrates such as polypropylene substrates.

Here, "polypropylene" refers to a polymer whose base unit is a structural unit derived from propylene. "Ethylene-propylene copolymer" refers to a copolymer whose base units are structural units derived from ethylene and propylene. "Propylene-1-butene copolymer" refers to a copolymer whose base units are structural units derived from propylene and butene. "Ethylene-propylene-1-butene copolymer" refers to a copolymer whose base units are structural units derived from ethylene, propylene and butene. As long as the amount does not significantly impair the inherent performance of the resin, these (co)polymers may contain small amounts of structural units derived from olefins other than the base units.

It is preferable that the polyolefin resin contains 50 mol % or more of propylene-derived structural units out of 100 mol % of structural units. If the propylene-derived structural units are contained in the above range, adhesion to non-polar resin substrates such as propylene resins can be maintained.

When the ethylene-propylene copolymer or propylene-1-butene copolymer is a random copolymer, preferably, out of 100 mol % of the structural units, the structural units derived from ethylene or the structural units derived from butene account for 3 to 50 mol % and the structural units derived from propylene account for 50 to 97 mol %.

The lower limit of the melting point of the polyolefin resin is preferably 50°C or higher, and more preferably 60°C or higher. When the melting point of the polyolefin resin is 50°C or higher, the modified polyolefin resin can exhibit sufficient coating strength when used for applications such as inks and paints. Therefore, adhesion to the substrate can be fully exhibited. Furthermore, when used as an ink, blocking during printing can be suppressed. The upper limit is preferably 120°C or lower, more preferably 110°C or lower, and even more preferably 100°C or lower. When the melting point of the polyolefin resin is 120°C or lower, the modified polyolefin resin can be prevented from becoming too hard when used for applications such as inks and paints. Therefore, the coating film can exhibit moderate flexibility.

In one embodiment, the melting point of the polyolefin resin is preferably 50 to 120°C, more preferably 60 to 110°C, and even more preferably 60 to 100°C.

(α,β-Unsaturated carboxylic acids and their anhydrides)
The α,β-unsaturated carboxylic acid and its anhydride are usually α,β-unsaturated carboxylic acid, its derivatives and their anhydrides, such as maleic acid, maleic anhydride, fumaric acid, citraconic acid, citraconic anhydride, mesaconic acid, itaconic acid, itaconic anhydride, aconitic acid, aconitic anhydride, himic anhydride, (meth)acrylic acid and (meth)acrylic acid esters. The (meth)acrylic acid esters are preferably esters of (meth)acrylic acid and a hydrocarbon group having 8 to 18 carbon atoms, such as lauryl (meth)acrylate, tridecyl (meth)acrylate, octyl (meth)acrylate and isodecyl (meth)acrylate. The α,β-unsaturated carboxylic acid and its anhydride are preferably maleic anhydride, taking into consideration the grafting property to polyolefin resins.

The graft weight of the α,β-unsaturated carboxylic acid and its anhydride is usually 0.1% by weight or more, preferably 0.2% by weight or more, and more preferably 0.3% by weight or more, based on the polyolefin resin. The upper limit is usually 10% by weight or less, preferably 5% by weight or less, more preferably 3% by weight or less, and even more preferably 1% by weight or less. The graft weight can be determined, for example, by alkali titration, and the graft weight of the (meth)acrylic acid ester can be determined by ^1H -NMR.

The polyolefin resin may be modified with at least one selected from α,β-unsaturated carboxylic acids and their anhydrides, or may be modified with a combination of two or more.

(Graft Modification)
Methods for modifying polyolefin resins with α,β-unsaturated carboxylic acids or their anhydrides include, for example, graft modification (introduction by graft copolymerization). The conditions for graft copolymerization are not particularly limited, and the polymerization may be carried out according to known methods such as a melting method or a solution method. In the case of the melting method, the operation is simple and the reaction can be carried out in a short time. In the case of the solution method, there are few side reactions and a uniform graft polymer is obtained.

In the melting method, for example, polyolefin is heated and melted (heated and melted) in the presence of a radical reaction initiator to cause a reaction. The temperature of heat melting may be equal to or higher than the melting point, and is preferably equal to or higher than the melting point and equal to or lower than 300°C. When heat melting, equipment such as a Banbury mixer, kneader, and extruder can be used. In the solution method, for example, polyolefin is dissolved in an organic solvent, and then heated and stirred in the presence of a radical reaction initiator to cause a reaction. As the organic solvent, aromatic solvents such as toluene and xylene are preferred. The temperature during the reaction is preferably 100 to 180°C. Examples of radical reaction initiators used in the melting method and solution method include organic peroxide compounds and azonitriles. Examples of organic peroxide compounds include di-tert-butyl peroxide, dicumyl peroxide, tert-butylcumyl peroxide, benzoyl peroxide, dilauryl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, cumene hydroperoxide, tert-butyl hydroperoxide, 1,1-bis(tert-butylperoxy)-3,5,5-trimethylcyclohexane, 1,1-bis(tert-butylperoxy)-cyclohexane, cyclohexanone peroxide, tert-butylperoxybenzoate, tert-butylperoxyisobutyrate, tert-butylperoxy-3,5,5-trimethylhexanoate, tert-butylperoxy-2-ethylhexanoate, tert-butylperoxyisopropyl carbonate, and cumyl peroxyoctoate. Examples of azonitriles include 2,2-azobis(2-methylbutyronitrile), 2,2-azobisisobutyronitrile, 2,2-azobis(2,4-dimethylvaleronitrile), and 2,2-azobis(4-methoxy-2,4-dimethylvaleronitrile).

(Chlorination)
The modified polyolefin may be chlorinated.
The chlorination method may include a method of blowing chlorine gas into the copolymer to introduce chlorine atoms. More specifically, the chlorination may be carried out by dispersing or dissolving the polyolefin or the polyolefin modified with another modifying agent in a solvent as necessary, and then blowing chlorine gas into the copolymer in the presence of a catalyst or under irradiation with ultraviolet light at a temperature range of 50 to 140°C under pressure or normal pressure. Examples of the solvent include water and chlorine-based solvents (e.g., chloroform, methylene chloride, carbon tetrachloride), and chlorine-based solvents are preferred. The chlorine-based solvent may be distilled off under reduced pressure or the like at the end of the chlorination, or may be replaced with another organic solvent. Examples of the catalyst include radical polymerization initiators. Examples of the radical polymerization initiator include organic peroxide compounds and azonitriles (e.g., 2,2-azobisisobutyronitrile). Examples of organic peroxide compounds include t-butyl peroxyoctoate, di-t-butyl peroxide, dicumyl peroxide, t-butylcumyl peroxide, benzoyl peroxide, dilauryl peroxide, cumene hydroperoxide, t-butyl hydroperoxide, 1,4-bis[(t-butylperoxy)isopropyl]benzene, 1,1-bis(t-butylperoxy)-3,5,5-trimethylcyclohexane, 1,1-bis(t-butylperoxy)-cyclohexane, Examples of the radical polymerization initiator include hexane, cyclohexanone peroxide, t-butyl peroxybenzoate, t-butyl peroxyisobutyrate, t-butyl peroxy-3,5,5-trimethylhexanoate, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxyisopropyl carbonate, cumyl peroxyoctoate, and combinations of two or more of these. Preferred are t-butyl peroxyoctoate, di-t-butyl peroxide, dicumyl peroxide, and dilauryl peroxide. The amount of radical polymerization initiator added is preferably 1% by weight or more, more preferably 10% by weight or more, based on the total amount (weight) of the other modifiers added. This allows a sufficient chlorine content to be maintained. The upper limit may be 100% by weight or less, more preferably 50% by weight or less. This allows the weight average molecular weight of the modified polyolefin to be prevented from decreasing.

When the modified polyolefin is chlorinated, the order of chlorination and modification with an α,β-unsaturated carboxylic acid or anhydride thereof is not particularly limited, but it is preferable to carry out chlorination later.
The chlorine content of the chlorinated polyolefin is not particularly limited, but examples are as follows: Usually, it is 15% by weight or more, preferably 20% by weight or more. The upper limit is not particularly limited, but it is usually 45% by weight or less, preferably 40% by weight or less. The chlorine content can be measured based on JIS-K7229. The chlorine content may be appropriately adjusted depending on conditions such as the type of polyolefin resin, the scale of the chlorination reaction, and the reaction apparatus used for chlorination, and can be adjusted by the amount or time of blowing in chlorine gas.

(Weight average molecular weight)
The weight average molecular weight of the modified polyolefin resin is preferably 200,000 or less, more preferably 180,000 or less, and even more preferably 150,000 or less. The lower limit is usually 10,000 or more, preferably 20,000 or more, and more preferably 30,000 or more. The weight average molecular weight can be determined from a standard polystyrene calibration curve by gel permeation chromatography (GPC).

The polyolefin resin component (A) may be a single type or a combination of multiple types.

[(B) High-boiling hydroxy compound]
Component (B) includes ethylene glycol 2-ethylhexyl ether, ethylene glycol monohexyl ether, 2-ethylhexanol, α-terpineol, 1-octanol, lauryl alcohol, cetyl alcohol, stearyl alcohol, oleyl alcohol, diethylene glycol dibutyl ether, and diethylene glycol mono 2-ethylhexyl ether, and is preferably a compound selected from the group consisting of ethylene glycol 2-ethylhexyl ether, ethylene glycol monohexyl ether, and 2-ethylhexanol, having a boiling point of 180° C. or higher and a solubility in water of 1.0 or lower. By adding component (B), the water resistance of the composition during low-temperature drying can be improved. It is presumed that the cause of lifting of the coating film during low-temperature drying is probably the absorption of moisture by the primer layer from the topcoat paint, and it is considered that such moisture absorption can be suppressed by adding component (B).

The above compound of component (B) has a boiling point of 180° C. or more and a water solubility of 1.0 or less. The upper limit of the boiling point is usually 300° C. or less, but is not particularly limited. As described above, the upper limit of the water solubility is preferably 1.0 or less, more preferably 0.5 or less, and even more preferably 0.3 or less. The lower limit of the water solubility is usually 0.05 or more, but is not particularly limited. In this specification, the water solubility refers to the weight (g) of component (B) that is completely dissolved when component (B) is added to 100 g of water at 20° C.
Compounds having a boiling point of 180° C. or higher and a solubility in water of 1.0 or less include ethylene glycol 2-ethylhexyl ether, ethylene glycol monohexyl ether, 2-ethylhexanol, α-terpineol, 1-octanol, lauryl alcohol, cetyl alcohol, stearyl alcohol, oleyl alcohol, diethylene glycol dibutyl ether, and diethylene glycol mono 2-ethylhexyl ether , and preferably ethylene glycol 2-ethylhexyl ether, ethylene glycol monohexyl ether, and 2-ethylhexanol.

[(C) Hydroxy compounds other than (B)]
Component (C) is a compound selected from the group consisting of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monoisobutyl ether, ethylene glycol mono-t-butyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, and 3-methyl-3-methoxybutanol, which has a boiling point of less than 180° C. and a solubility in water of more than 1.0. By using component (C), the effect of adding component (B) can be efficiently exhibited.

The hydroxy compound of component (C) has a boiling point of less than 180° C. and a water solubility of more than 1.0. The lower limit of the boiling point and the upper limit of the water solubility of the compound having a boiling point of less than 180° C. and a water solubility of more than 1.0 are not particularly limited, but the compound usually has a boiling point of 120° C. or more and less than 180° C., and a water solubility of 5.0 or more (easily soluble). Examples of such compounds include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monoisobutyl ether, ethylene glycol mono-t-butyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, and 3-methyl-3-methoxybutanol, and preferably ethylene glycol monobutyl ether.

〔composition〕
--Amount of component (B)--
The amount of component (B) is usually 0.01% by weight or more, preferably 0.05% by weight or more, more preferably 0.1% by weight or more, based on the aqueous dispersion composition. The upper limit is usually 10% by weight or less, preferably 5% by weight or less. Therefore, the amount is usually 0.01 to 10% by weight, preferably 0.05 to 5% by weight, more preferably 0.1 to 5% by weight.

--Amount of component (C)--
When component (C) is contained, the amount thereof is usually 0.01% by weight or more, preferably 0.05% by weight or more, more preferably 1% by weight or more, based on the aqueous dispersion composition. The upper limit is usually 10% by weight or less, preferably 5% by weight or less, more preferably 3% by weight or less. Therefore, the amount is usually 0.01 to 10% by weight, more preferably 0.1 to 5% by weight, more preferably 1 to 3% by weight.

--Amount of component (A) (solid content)--
The amount (solid content) of component (A) is usually 5% by weight or more, preferably 10% by weight or more, more preferably 15% by weight or more, based on the aqueous dispersion composition. The upper limit is usually 50% by weight or less, preferably 40% by weight or less, more preferably 35% by weight or less. Thus, it is usually 5 to 50% by weight, preferably 10 to 40% by weight, more preferably 15 to 35% by weight.

-Component (B) + (C)-
When both components (B) and (C) are contained, the total amount is usually 0.08 to 15% by weight, preferably 1 to 10% by weight.

-Component (B)/(C)-
When both components (B) and (C) are contained, the ratio of the amount of component (B) to the amount of (C) (B/C) is usually 0.05 to 3%, preferably 0.1 to 2%.

[Optional ingredients]
Examples of other components include unreacted raw materials of component (A) (unmodified polyolefin resin, α,β-unsaturated carboxylic acid or anhydride monomer thereof), resin components other than component (A), solvents other than (B) and (C), emulsifiers, stabilizers, basic substances, crosslinking agents, and additive components (e.g., lower alcohols, lower ketones, lower esters, metal salts, acids, preservatives, leveling agents, antioxidants, light stabilizers, ultraviolet absorbers, dyes, pigments, diluents, inorganic fillers, and the like), and can be selected according to the application.

-Other resin components-
Examples of the other resin component include urethane resin, epoxy resin, acrylic resin, phenol resin, alkyd resin, polyamide resin, polyimide resin, silicone resin, nitrocellulose, and combinations of two or more of these. These resins may be blended as aqueous products (e.g., aqueous acrylic resin, aqueous polyurethane resin). The ratio of the blending amount of component (A) and the other resin (total amount when the other resin is two or more) is usually modified polyolefin resin:other resin=1 to 99:99 to 1, preferably 10 to 90:90 to 10, more preferably 20 to 80:80 to 20, and even more preferably 30 to 70:70 to 30, calculated on solid basis.

-solvent-
The solvent is usually an aqueous solvent. The aqueous solvent is usually water, and may further include an alcohol solvent, a glycol solvent, a ketone solvent, or an ester solvent other than (B) and (C). A small amount of an organic solvent (e.g., toluene, xylene) may also be included.

- Emulsifier (surfactant) -
As the emulsifier (surfactant), either a nonionic surfactant or an anionic surfactant can be used. A nonionic surfactant is preferably used because it improves the water resistance of the resulting aqueous dispersion composition.

Nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkylene alkyl ethers, polyoxyethylene derivatives, polyoxyethylene fatty acid esters, polyoxyethylene polyhydric alcohol fatty acid esters, polyoxyethylene propylene polyols, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene hydrogenated castor oil, polyoxyalkylene polycyclic phenyl ethers, polyoxyethylene alkylamines, alkyl alkanolamides, and polyalkylene glycol (meth)acrylates. Among these, polyoxyethylene alkyl ethers, polyoxyethylene fatty acid esters, polyoxyethylene sorbitan fatty acid esters, and polyoxyethylene alkylamines are preferred.

Examples of anionic surfactants include alkyl sulfate ester salts, polyoxyethylene alkyl ether sulfate salts, alkylbenzene sulfonates, α-olefin sulfonates, methyl tauryl salts, sulfosuccinate salts, ether sulfonates, ether carboxylate salts, fatty acid salts, naphthalenesulfonate-formaldehyde condensates, alkylamine salts, quaternary ammonium salts, alkyl betaines, and alkylamine oxides. Among these, polyoxyethylene alkyl ether sulfate salts and sulfosuccinate salts are preferred.

It is preferable to add a small amount of surfactant or no surfactant at all. The reason for this is that adding a surfactant may reduce the performance of the coating when it is made, or may cause a plasticizing effect or bleeding phenomenon when it is dried, resulting in blocking.

-Neutralizing agent-
The aqueous dispersion composition may further contain a neutralizing agent. This can further enhance the dispersibility of the resin such as component (A) in the composition. Examples of the neutralizing agent include ammonia, methylamine, ethylamine, dimethylamine, diethylamine, triethylamine, propylamine, isopropylamine, dipropylamine, isobutylamine, hexylamine, octylamine, ethanolamine, propanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N,N-dimethylethanolamine, N,N-diethylethanolamine, N,N-dibutylethanolamine, 2-dimethylamino-2-methyl-1-propanol, 2-amino-2-methyl-1-propanol, and the like. N-propanol, 2-amino-2-ethyl-1,3-propanediol, 2-aminoethanol, 2-dimethylaminoethanol, 2-diethylaminoethanol, 3-ethoxypropylamine, 3-diethylaminopropylamine, sec-butylamine, n-butylamine, 2-methoxyethylamine, 3-methoxypropylamine, 2,2-dimethoxyethylamine, morpholine, N-methylmorpholine, N-ethylmorpholine, piperazines, pyrrole, pyridine, sodium hydroxide, potassium hydroxide, magnesium hydroxide, and other metal hydroxides. Among these, from the viewpoint of ease of emulsification and dispersion, morpholine, N,N-dimethylethanolamine, N,N-diethylethanolamine, and 2-amino-2-methyl-1-propanol are preferred.

The boiling point of the neutralizing agent at normal pressure is preferably 200°C or less. If the boiling point exceeds 200°C, for example, when the aqueous dispersion composition is used as a coating film, it may be difficult to remove the neutralizing agent by the drying treatment in the water removal process. As a result, the water resistance and moisture resistance of the coating film may deteriorate, especially when dried at low temperatures, or the adhesion to substrates such as non-polar resin molded products may deteriorate.

Neutralizing agents may be used alone or in combination of two or more. When two or more types are used in combination, the compounding ratio of each compound is not particularly limited.

In the aqueous dispersion composition, the content of the neutralizing agent is not particularly specified, but it is preferably 3.0 times equivalent or less relative to the carboxyl group in the graft modified product. This makes it possible to suppress an excessive increase in the pH of the aqueous dispersion composition. The lower limit is preferably 0.5 times equivalent or more. This makes it possible to suppress an excessive decrease in the pH of the aqueous dispersion composition.

-Stabilizer-
Examples of the stabilizer include compounds containing an epoxy ring, such as epoxy-based stabilizers. Examples of the epoxy-based stabilizer include epoxy compounds having an epoxy equivalent of about 100 to 500 and containing one or more epoxy groups in one molecule. More specifically, the following compounds may be mentioned: epoxidized soybean oil or epoxidized linseed oil obtained by epoxidizing a vegetable oil having a natural unsaturated group with a peracid such as peracetic acid; epoxidized fatty acid esters obtained by epoxidizing unsaturated fatty acids such as oleic acid, tall oil fatty acid, and soybean oil fatty acid; epoxidized alicyclic compounds typified by epoxidized tetrahydrophthalate; monoepoxy compounds typified by condensation of bisphenol A or polyhydric alcohol with epichlorohydrin, such as bisphenol A glycidyl ether, ethylene glycol glycidyl ether, propylene glycol glycidyl ether, glycerol polyglycidyl ether, and sorbitol polyglycidyl ether; butyl glycidyl ether, 2-ethylhexyl glycidyl ether, decyl glycidyl ether, stearyl glycidyl ether, allyl glycidyl ether, phenyl glycidyl ether, sec-butylphenyl glycidyl ether, tert-butylphenyl glycidyl ether, and phenol polyethylene oxide glycidyl ether. The stabilizer may be a compound that does not contain an epoxy ring, and examples of the stabilizer include metal soaps such as calcium stearate and lead stearate, which are used as stabilizers for polyvinyl chloride resins; organometallic compounds such as dibutyltin dilaurate and dibutyl maleate; and hydrotalcite compounds.

Stabilizers that do not contain epoxy rings may also be used, and examples of such stabilizers include metal soaps such as calcium stearate and lead stearate, which are used as stabilizers for polyvinyl chloride resins; organometallic compounds such as dibutyltin dilaurate and dibutyl maleate; and hydrotalcite compounds.

The content of the stabilizer is preferably 0.1% by weight or more, more preferably 1% by weight or more, and even more preferably 2% by weight or more, based on 100% by weight of the modified polyolefin resin. This allows the stabilizing effect to be well expressed. The upper limit is preferably 15% by weight or less, more preferably 12% by weight or less, and even more preferably 10% by weight or less. This allows the adhesiveness to substrates such as polyolefins to be well expressed.

[Physical Properties]
-viscosity-
The viscosity of the aqueous dispersion composition is preferably from 1 to 200 mPa·s, and more preferably from 1 to 100 mPa·s. In this specification, the viscosity is a value measured at 25° C. using a B-type viscometer.

-Average particle size-
The average particle size of the resin dispersed in the aqueous dispersion composition is preferably 300 nm or less, more preferably 200 nm or less. If it exceeds 300 nm, the storage stability of the aqueous dispersion composition and the compatibility with other resins may deteriorate. In addition, when a coating is formed, the physical properties of the coating, such as adhesion to the substrate, solvent resistance, water resistance, and blocking resistance, may decrease. The average particle size can be adjusted by conditions such as the composition of the modified polyolefin resin, the amount of the dispersion medium, the amount and type of the emulsifier added, and the stirring force during dispersion. In this specification, the average particle size is a value obtained by particle size distribution measurement using a light diffusion method. By increasing the amount of emulsifier added, the particle size can be made as small as possible. However, by increasing the amount of emulsifier added, the coating properties, such as adhesion to the substrate, water resistance, and gas hole resistance, tend to decrease.

-pH-
The pH of the aqueous dispersion composition is preferably 5 or more, more preferably 6 to 11. If the pH is less than 5, neutralization is insufficient, and the modified polyolefin resin may not disperse in water. Even if the modified polyolefin resin is dispersed, it may easily precipitate or separate over time, resulting in poor storage stability. On the other hand, if the pH is more than 11, problems may arise in compatibility with other components and operational safety. The pH can be adjusted by the amount of neutralizing agent added when preparing the aqueous dispersion composition.

--Melting point (Tm)--
The Tm of the aqueous dispersion composition is preferably 50°C or more and less than 120°C, more preferably 60°C or more and less than 110°C, and more preferably 60°C or more and less than 100°C. When the Tm is 50°C or more, sufficient water resistance under high temperature conditions can be further improved. On the other hand, when the melting point is less than 120°C, good film-forming properties can be ensured during coating baking. In this specification, the Tm of the dispersion composition can be measured by drying the dispersion composition at 40°C for 24 hours, using a DSC (manufactured by TA Instruments) in the same manner as the Tm of the modified polyolefin resin described above.

[Application]
The aqueous dispersion composition of the present invention can function as an intermediate medium for substrates that have poor adhesion and are difficult to coat with paint, such as non-polar resin molded products. For example, it is also useful as an adhesive between polyolefin substrates such as polypropylene and polyethylene that have poor adhesion, and can be used regardless of whether the substrate, such as a non-polar resin molded product, has been subjected to surface treatment such as plasma treatment or corona treatment.

In addition, the dispersion composition of the present invention can be laminated by hot melt onto the surface of a non-polar resin molded product such as a polyolefin-based substrate, and then a paint or the like can be applied on top of the laminate, thereby improving the adhesion stability of the paint.

It is also suitable for polar substrates such as polyesters such as polyethylene terephthalate, polyurethanes, and polyamides.

That is, the aqueous dispersion composition of the present invention can be suitably used as a primer, paint, ink, adhesive, etc.

[Method for producing aqueous dispersion composition]
The method for producing the aqueous dispersion composition is not particularly limited. For example, a method including at least blending and emulsifying components (A) to (B), preferably components (A) to (C), can be mentioned. By adding component (B) during emulsification, a high boiling point solvent can be encapsulated in the particles, and it is presumed that component (B) can be uniformly distributed in the coating film during film formation, and the water resistance effect of the resulting aqueous dispersion composition is expressed. After emulsification, if necessary, components (B) and (C) are distilled off except for a part, and then an aqueous solvent is usually added to the system and dispersed to obtain an aqueous dispersion composition. When a neutralizing agent is used, it is preferable to add the neutralizing agent when blending components (A) to (C). When the dispersion composition contains other resin components, it is preferable to blend the resin components after the above-mentioned dispersion step. For example, after the dispersion step, a resin component blending step may be performed in which the resin components are blended and the solid content is adjusted as necessary (for example, by adding a dispersion medium to dilute).

The present invention will be described in detail below with reference to examples. The following examples are provided to better explain the present invention and are not intended to limit the present invention. The methods for measuring physical properties are as described below unless otherwise specified.

[Example 1]
In a four-neck flask equipped with a stirrer, a cooling tube, a dropping funnel, and a thermometer, 100 g of component (A): propylene-butene random copolymer [P-B] (propylene component 70 mol%, butene component 30 mol%) modified with maleic anhydride [MAH] (weight average molecular weight [Mw] 150,000, Tm = 75 ° C.), 10 g of surfactant Emulgen 420 (polyoxyethylene oleyl ether, Kao Corporation), 45 g of toluene, 5 g of component (B): ethylene glycol 2-ethylhexyl ether, and 45 g of component (C): ethylene glycol monobutyl ether were added and kneaded for 60 minutes at an internal temperature of 95 ° C. Then, 4 g of 2-amino-2-methyl-1-propanol 90% aqueous solution [AMP-90] was added and kneaded for 30 minutes, and then 341 g of deionized water at 90 ° C. was added over 90 minutes. Subsequently, toluene and a portion of component (B): ethylene glycol 2-ethylhexyl ether and component (C): ethylene glycol monobutyl ether were removed under reduced pressure, and the mixture was cooled to room temperature with stirring, and the solid content was adjusted to 30% by weight with deionized water to obtain a modified polyolefin resin water dispersion composition. The average particle size of the modified polyolefin resin water dispersion composition obtained was 139 nm, and the viscosity was 14 mPa·s. Furthermore, the contents of component (B): ethylene glycol 2-ethylhexyl ether and component (C): ethylene glycol monobutyl ether in the modified polyolefin resin water dispersion composition were confirmed by gas chromatography, and were found to be 0.9% by weight and 2.07% by weight, respectively, relative to the modified polyolefin resin water dispersion composition.

[Example 2]
A modified polyolefin resin water dispersion composition was obtained in the same manner as in Example 1, except that component (B) was changed to ethylene glycol monohexyl ether. The average particle size of the obtained modified polyolefin resin water dispersion composition was 136 nm, and the viscosity was 16 mPa·s. The contents of component (B): ethylene glycol monohexyl ether and component (C): ethylene glycol monobutyl ether in the modified polyolefin resin water dispersion composition were confirmed by gas chromatography and found to be 1.09% by weight and 2.14% by weight, respectively, relative to the modified polyolefin resin water dispersion composition.

[Example 3]
A modified polyolefin resin water dispersion composition was obtained in the same manner as in Example 1, except that component (B) was changed to 2-ethylhexanol, the amount of component (C): ethylene glycol monobutyl ether added was changed to 40 g, and 5 g of isopropyl alcohol was added. The average particle size of the obtained modified polyolefin resin water dispersion composition was 159 nm, and the viscosity was 13 mPa·s. Furthermore, the contents of component (B): 2-ethylhexanol and component (C): ethylene glycol monobutyl ether in the modified polyolefin resin water dispersion composition were confirmed by gas chromatography, and were 0.12% by weight and 1.26% by weight, respectively, relative to the modified polyolefin resin water dispersion composition.

[Example 4]
A modified polyolefin resin water dispersion composition was obtained in the same manner as in Example 1, except that the amount of component (B): ethylene glycol 2-ethylhexyl ether was changed to 10 g, the amount of component (C): ethylene glycol monobutyl ether was changed to 40 g, and 5 g of isopropyl alcohol was further added. The average particle size of the obtained modified polyolefin resin water dispersion composition was 170 nm and 56 mPa·s. Furthermore, the contents of component (B): ethylene glycol 2-ethylhexyl ether and component (C): ethylene glycol monobutyl ether in the modified polyolefin resin water dispersion composition were confirmed by gas chromatography, and were 1.77% by weight and 0.98% by weight, respectively, relative to the modified polyolefin resin water dispersion composition.

[Example 5]
A modified polyolefin resin water dispersion composition was obtained in the same manner as in Example 4, except that the amount of component (B): ethylene glycol 2-ethylhexyl ether added was changed to 15 g. The average particle size of the obtained modified polyolefin resin water dispersion composition was 190 nm, and the viscosity was 85 mPa·s. Furthermore, the contents of component (B): ethylene glycol 2-ethylhexyl ether and component (C): ethylene glycol monobutyl ether in the modified polyolefin resin water dispersion composition were confirmed by gas chromatography, and were found to be 2.8% by weight and 2.2% by weight, respectively, relative to the modified polyolefin resin water dispersion composition.

[Comparative Example 1]
A modified polyolefin resin water dispersion composition was obtained in the same manner as in Example 1, except that component (B) was not used. The average particle size of the obtained modified polyolefin resin water dispersion composition was 143 nm, and the viscosity was 9 mPa·s. The content of component (C): ethylene glycol monobutyl ether in the modified polyolefin resin water dispersion composition was confirmed by gas chromatography, and was 0.89% by weight relative to the modified polyolefin resin water dispersion composition.

[Comparative Example 2]
A modified polyolefin resin water dispersion composition was obtained in the same manner as in Example 1, except that diethylene glycol monoethyl ether was used as the high boiling point solvent instead of component (B). The average particle size of the obtained modified polyolefin resin water dispersion composition was 166 nm, and the viscosity was 18 mPa·s. The contents of component (C): ethylene glycol monobutyl ether and other component: diethylene glycol monoethyl ether in the modified polyolefin resin water dispersion composition were confirmed by gas chromatography, and were 0.9% by weight and 0.9% by weight, respectively, relative to the modified polyolefin resin water dispersion composition.

[Average particle diameter (nm)]
The average particle size was measured using a Zetasizer Nano ZS (manufactured by Malvern Instruments), which is a measuring device that utilizes dynamic light scattering. The emulsifiability was evaluated according to the following evaluation criteria.
(Evaluation criteria: emulsification)
◯: average particle size less than 180 nm △: average particle size 180 to less than 250 nm ×: average particle size more than 250 μm or poor emulsification

[Viscosity measurement (mPa・s)]
The measurement was carried out using a Brookfield viscometer (manufactured by Toki Sangyo Co., Ltd.) at a measurement temperature of 25° C. and a rotor rotation speed of 60 rpm.

[Adhesion measurement]
<Preparation of test specimen>
The surface of the ultra-high rigidity polypropylene plate was degreased with isopropyl alcohol, and a modified polyolefin resin water dispersion composition (wetting agent was added at 1.5% relative to the surface) was spray-painted so that the dry film thickness was 15 to 20 μm, and preheated at 80 ° C for 5 minutes. After leaving it at room temperature for 10 minutes, a topcoat paint was mixed with a predetermined hardener and the viscosity was adjusted with a dedicated thinner, and then spray-painted on the coating film so that the dry film thickness was 100 μm. Next, a baking treatment was performed at 80 ° C for 30 minutes to prepare a test piece. The following tests were performed using this test piece.

<Adhesion measurement>
A Tensilon (RTG-1210, manufactured by Orientec Co., Ltd.) was used for measuring the adhesion strength. The coating film obtained by spray coating was cut into a width of 10 mm, and the adhesion strength to the substrate was measured. The peeling conditions were a peel angle of 180° and a peeling speed of 50 mm/min, and the results were evaluated according to the following evaluation criteria.
(Evaluation Criteria)
◯: 900 gf/cm or more ×: less than 900 gf/cm

[Water resistance test]
<Preparation of test specimen>
The surface of the ultra-high rigidity polypropylene plate was degreased with isopropyl alcohol, and a modified polyolefin resin water dispersion composition (wetting agent was added at 1.5% by mass) was spray-painted so that the dry coating film was 15 to 20 μm thick, and the plate was preheated at 60° C. for 5 minutes. After leaving the plate at room temperature for 10 minutes, the plate was baked at 60° C. or 70° C. for 30 minutes to prepare a test specimen. The following tests were carried out using the test specimen.

<Water resistance test>
About 0.1 ml of deionized water was dropped onto the test piece obtained by the spray coating, and the test piece was covered with a petri dish and held for 3 minutes, after which the ion-exchanged water was removed and the appearance of the coating film (presence or absence of blistering, etc.) was evaluated according to the following criteria. The test was performed twice.
(Evaluation criteria: coating appearance)
◯: No abnormality at baking temperatures of 60°C and 70°C △: Blisters occurred only at a baking temperature of 60°C ×: Blisters occurred at baking temperatures of 60°C and 70°C

As can be seen from Tables 1 and 2, the coating appearance after the water resistance test was better in the examples using component (B) than in Comparative Example 1, in which component (B) was not used, and Comparative Example 2, in which another component having a boiling point of 180°C or higher and a solubility in water of 1.0 or higher was used instead of component (B). These results show that the modified polyolefin resin water dispersion composition of the present invention can exhibit good adhesion to substrates such as polyolefin resin substrates even at low baking temperatures, and can also exhibit excellent water resistance, and can have good film-forming properties.

Claims (10)

Component (A): a modified polyolefin resin in which at least one selected from an α,β-unsaturated carboxylic acid or an anhydride thereof is grafted onto a polyolefin resin;
Component (B): at least one compound selected from the group consisting of ethylene glycol 2-ethylhexyl ether, ethylene glycol monohexyl ether, and 2-ethylhexanol, the compound having a boiling point of 180° C. or higher and a solubility in water of 1.0 or lower ;
Component (C): At least one compound selected from the group consisting of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monoisobutyl ether, ethylene glycol mono-t-butyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, and 3-methyl-3-methoxybutanol, which has a boiling point of less than 180° C. and a solubility in water of more than 1.0.
An aqueous dispersion composition comprising at least The aqueous dispersion composition according to claim 1, wherein the content of component (B) is 0.01 to 10% by weight. The aqueous dispersion composition according to claim 1 or 2, wherein the polyolefin resin is one or more polyolefin resins selected from the group consisting of polypropylene, propylene-butene copolymer, ethylene-propylene copolymer, and ethylene-propylene-butene copolymer. The aqueous dispersion composition according to any one of claims 1 to 3, wherein the weight average molecular weight of the modified polyolefin resin is 10,000 to 250,000. The aqueous dispersion composition according to any one of claims 1 to 4, wherein the ratio of the amount of component (B) to the amount of component (C) is 0.05 to 3%. The aqueous dispersion composition according to any one of claims 1 to 5, wherein the content of component (C) is 0.01 to 10% by weight. A primer comprising the aqueous dispersion composition according to any one of claims 1 to 6. An adhesive comprising the aqueous dispersion composition according to any one of claims 1 to 6. A paint binder comprising the aqueous dispersion composition according to any one of claims 1 to 6. An ink binder comprising the aqueous dispersion composition according to any one of claims 1 to 6.