JP2003041186A - Water-dispersed polyurethane composition for coating metallic material free from chrome finishing and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water-dispersed polyurethane composition suitable as a coating material for a metallic material free from chrome finishing and imparting the material with adhesivity to a substrate, alkali resistance and solvent resistance. SOLUTION: The water-dispersed polyurethane composition is composed of a polyisocyanate component at least containing an alicyclic polyisocyanate such as dicyclohexylmethane diisocyanate, a polyhydroxy component at least containing a polyhydroxy compound having an aromatic ring such as a polyester polyol derived from 3-methyl-1,5-pentanediol and terephthalic acid, melamine, a silane compound such as γ-aminopropyltriethoxysilane, a chain extender component at least containing a dicarboxylic acid dihydrazide such as adipic acid dihydrazide and water.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-dispersed polyurethane composition used for non-chromium-treated metal material coatings used in home appliances, building materials, etc. More specifically, it relates to a metal material not treated with chromium. The present invention relates to a water-dispersed polyurethane composition having a specific composition used for paints such as precoat paints, precoat primer paints and lubricating paints, and a method for producing the same.

[0002]

2. Description of the Related Art Metallic materials such as steel plates used for home appliances, building materials, automobiles, etc. are required to have corrosion resistance. Therefore, a primer should contain a chromium-based rust preventive pigment. Alternatively, a chromium treatment for applying a chromate treatment film is performed as a primer base treatment.
In particular, in the anticorrosive use of zinc-based plated steel sheets, a chromate-treated film is used as a corrosion resistance imparting film.

However, since hexavalent chromium may be eluted from the chromate-treated film and the organic film containing a chromium-based rust preventive pigment, recently, from the viewpoint of environmental pollution, occupational health and safety, non-chrome rust preventive treatment and non-chromium are recently used. The demand for organic coatings is increasing.

On the other hand, the paints for metal materials used for coating metals are also water-based paints from the viewpoints of environmental pollution, occupational health and safety. Various resin materials such as polyurethane and epoxy resin have been used as these resin components, but polyurethane is suitable because it has a good balance of physical properties such as elongation of the coating film and strength. For example,
JP-A-7-331160, JP-A-9-221629
No. 2000-73179, No. 2000-73179
The use of a water-dispersible polyurethane composition has been reported in Japanese Patent No. 107686.

However, the chromate treatment has the effect of increasing the adhesion of the coating layer to the underlying metal material,
For non-chromium metal materials not subjected to this, the above water-dispersible polyurethane composition has a problem that it does not impart sufficient adhesion to the coating material. In addition, the coated surface is required to have alkali resistance (alkali degreasing step) and solvent resistance (ethanol rubbing resistance) in the step after coating. Conventional water-dispersible polyurethane compositions have not been sufficient for these either.

Therefore, an object of the present invention is to provide a water-dispersible polyurethane composition which is suitable for a chromium-free metal coating material and which provides adhesion to a substrate, alkali resistance and solvent resistance.

[0007]

As a result of extensive studies, the inventors of the present invention found that a water-dispersed polyurethane composition obtained from a specific component and a compounding ratio can solve the above-mentioned problems. It came to completion.

That is, the first aspect of the present invention is a polyisocyanate component (a) containing an alicyclic polyisocyanate as an essential component and another polyisocyanate compound as an optional component, and a polyhydroxyl compound having an aromatic ring as an essential component. As a component, a polyhydroxyl compound component (b) containing another polyhydroxyl compound as an optional component, a melamine compound (c), a silane compound (d) represented by the following general formula (I), and a dicarboxylic acid dihydrazide compound. To provide a water-dispersible polyurethane composition for a chromium-free metal coating material obtained from water and a chain extender component (e) containing a diamine compound as an optional component.

[0009]

[Chemical 3]

(In the formula, X represents a hydrogen atom or 1 to 4 carbon atoms.
Represents an alkyl group of, 1 represents 0 or 1, and n represents
Represents 1, 2 or 3. R represents an alkyl group having 1 to 8 carbon atoms, Ram represents an organic group having an amino group or an NH group, Y represents a single bond, -O-, -S-, -N-, -NH.
Represents-, -NR'-, Z represents an alkylene group having 1 to 4 carbon atoms, m, Y represents a single bond, -O-, -S-, -NH.
In the case of-and -NR'-, it represents 1, when Y is -N-, it represents 2, and R'represents an organic group having 1 to 18 carbon atoms. ) A second aspect of the present invention is the chromium-free treatment according to the first aspect of the present invention, wherein the content of the polyhydroxyl compound containing an aromatic ring in the polyhydroxyl compound component (b) is 10 to 100% by mass. Provided is a water-dispersed polyurethane composition for metal material coating. A third aspect of the present invention is a water-dispersible type for non-chromium-treated metal material coating according to the first or second aspect of the present invention, wherein the polyhydroxyl compound having an aromatic ring is a polyester diol obtained from an aromatic dicarboxylic acid and a low molecular weight diol. A polyurethane composition is provided. Fourth of the present invention
Provides a water-dispersible polyurethane composition for non-chromium-treated metal material coating according to the first or second aspect of the present invention, wherein the polyhydroxyl compound containing an aromatic ring is a compound represented by the following general formula (II).

[0011]

[Chemical 4]

(In the formula, R ¹ and R ² each represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and A represents 2 to 4 carbon atoms.
Represents an alkylene group, and p and q represent 1 to 10. ) A fifth aspect of the present invention provides the water-dispersible polyurethane composition for a chromium-free metal coating according to any one of claims 1 to 4, wherein the polyhydroxyl compound component (b) contains an anionic group-introduced polyol. A sixth aspect of the present invention is the polyisocyanate component (a), the polyhydroxyl compound component (b), the melamine compound (c), which is the same as the first aspect of the present invention.
A method for producing a water-dispersible polyurethane composition for a non-chromium-treated metal coating by the following method (a), (b) or (c) using a silane compound (d) and a chain extender component (e). A prepolymer is synthesized from the polyisocyanate component (a), the polyhydroxyl compound component (b) and the melamine compound (c), and the prepolymer is synthesized in water with the silane compound (d).
And a method (a) of reacting with a chain extender component (e); a prepolymer is synthesized from a polyisocyanate component (a), a polyhydroxyl compound component (b), a melamine compound (c) and a silane compound (d), Method (b) of reacting this with a chain extender component (e) in water; polyisocyanate component (a), polyhydroxyl compound component (b), melamine compound (c), silane compound (d) and chain extender component A method (c) for synthesizing a polymer from (e) and feeding and dispersing the polymer in water is provided.
The seventh aspect of the present invention is a polyisocyanate component (a), a polyhydroxyl compound component (b), a melamine compound (c).
And synthesizing a prepolymer from the silane compound (d),
There is provided the production method according to the sixth aspect of the present invention, in which this is reacted with the chain extender component (e) in water.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below. The polyisocyanate component (a) according to the present invention comprises an alicyclic polyisocyanate which is an essential component and another polyisocyanate compound which is optionally used, and is not particularly limited by its blending and the like. Examples of the alicyclic polyisocyanate include isophorone diisocyanate and dicyclohexylmethane-
4,4'-diisocyanate, trans and / or cis-1,4-cyclohexane diisocyanate, norbornene diisocyanate and the like can be mentioned, and these may be used in the form of modified products such as carbodiimide modified, isocyanurate modified and biuret modified. Alternatively, it may be used in the form of a blocked isocyanate blocked with various blocking agents. If the content (mass%) of these alicyclic polyisocyanates in the component (a) is less than 50%, the water resistance may deteriorate, so 50% or more is preferable, and 70% or more is more preferable.

Further, in the above polyisocyanate component (a), other polyisocyanate compounds used as necessary include tolylene diisocyanate, diphenylmethane-4,4'-diisocyanate (MDI), p-phenylene diisocyanate, Aromatic diisocyanate compounds such as xylylene diisocyanate, 1,5-naphthylene diisocyanate, 3,3′-dimethyldiphenyl-4,4′-diisocyanate, dianisidine diisocyanate and tetramethylxylylene diisocyanate; 1,6-hexamethylene diisocyanate , 2,2,4 and / or (2,4,4) -trimethylhexamethylene diisocyanate, lysine diisocyanate and other aliphatic diisocyanate compounds; triphenylmethane triisocyanate, - methyl benzol -
Trifunctional or higher functional isocyanate compounds such as 2,4,6-triisocyanate, dimethyltriphenylmethanetetraisocyanate, and polymeric MDI having a high molecular weight of the above MDI are mentioned. These isocyanate compounds are carbodiimide-modified, isocyanurate-modified, biuret. It may be used in the form of a modified product such as a modification, or may be used in the form of a blocked isocyanate blocked with various blocking agents.

The polyhydroxyl compound component (b) according to the present invention comprises a polyhydroxyl compound having an aromatic ring as an essential component and another polyhydroxyl compound as an optional component, and these compounds are contained in the molecule. The hydroxyl group which reacts with the isocyanate group of the above polyisocyanate component (a) to form a urethane bond is 2
Have more than one.

Examples of the polyhydroxyl aromatic compound which is the above-mentioned essential component include, for example, catechol, resorcin, hydroquinone, 3-methylresorcin, 3-ethylresorcin, 3-propylresorcin, 3-butylresorcin, and 3-tert-butyl. Resorcin, 3-phenylresorcin, 3-cumylresorcin, 3-methylhydroquinone, 3-ethylhydroquinone, 3-propylhydroquinone, 3-butylhydroquinone, 3-tert-butylhydroquinone, 3-phenylhydroquinone, 3-
Cumyl hydroquinone 4,4'-dihydroxydiphenyl, 1,1-bis (4-hydroxyphenyl) -2,
4,4-trimethylcyclopentane, 1,1-bis (4
-Hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl) -3,3-dimethylcyclohexane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl)- 3,3,5-trimethylcyclohexane, 1,1
-Bis (4-hydroxy-3,5-dimethylphenyl)
Cyclohexane, 1,1-bis (4-hydroxyphenyl) cyclododecane, 1,1-bis (4-hydroxy-
3,5-Dimethylphenyl) cyclododecane, 1,1-
Bis (4-hydroxyphenyl) cyclododecane, 1,
4-bis (4-hydroxyphenylsulfonyl) benzene, 4,4-bis (4-hydroxyphenylsulfonyl) benzene, bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane (also known as bisphenol F), 1,2-bis (4-hydroxyphenoxy) ethane, 1,3-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxyphenyl) propane (also known as bisphenol A), 2,2
-Bis (3-chloro-4-hydroxyphenyl) propane, 2,2-bis (3,5-dichloro-4-hydroxyphenyl) propane, 2,2-bis (4-hydroxy-)
3,5-Dimethylphenyl) propane, 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, 2,2-bis (4-hydroxyphenyl-3-methylphenyl) propane, 2,2- Bis (4-hydroxyphenyl-3-cyclohexylphenyl) propane,
2,2-bis (4-hydroxy-3-tert-butylphenyl) propane, 2,2-bis (4-hydroxyphenyl-3-methoxyphenyl) propane, 1,1-bis (4
-Hydroxyphenyl) butane, 1,1-bis (4-hydroxyphenyl) isobutane, 2,2-bis (4-hydroxy) butane, 2,4-bis (4-hydroxyphenyl2-methyl) butane, and polys thereof. Examples thereof include ethylene oxide and / or propylene oxide adducts of hydroxyl aromatic compounds.

As the polyhydroxyl compound having an aromatic ring, a polyester diol obtained from an aromatic dicarboxylic acid and a low molecular diol in a low molecular polyol described later or a compound represented by the general formula (II) is obtained. The water-dispersed polyurethane composition to be used is preferable because it has good dispersion stability.

Examples of the above-mentioned optional polyol compound include low molecular weight polyols, polyether polyols, polyester polyols, polyester polycarbonate polyols, polycarbonate polyols, and the like, and ion group-introduced polyols described later.

Examples of the low molecular weight polyols include ethylene glycol, 1,2-propanediol,
1,3-propanediol, 2-methyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 1,4-butanediol, neopentyl glycol, 3-methyl-2, 4-pentanediol,
2,4-pentanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 2-methyl-2,4-pentanediol, 2,4-diethyl-
1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 3,5-heptanediol, 1,8-octanediol, 2-methyl-1,8
-Octanediol, 1,9-nonanediol, 1,1
Aliphatic diol compounds such as 0-decanediol, cyclohexanedimethanol, cyclohexanediol, alicyclic diol compounds such as hydrogenated bisphenol A, trimethylolethane, ditrimethylolethane, trimethylolpropane, ditrimethylolpropane, tetramethylolpropane, tetramethylolpropane, Examples thereof include trihydric or higher alcohol compounds such as hexitols, pentitols, glycerin, polyglycerin, pentaerythritol, and dipentaerythritol.

Examples of the polyether polyols include ethylene oxide adducts such as diethylene glycol and triethylene glycol, propylene oxide adducts such as dipropylene glycol and tripropylene glycol, and ethylene oxide and / or propylene of the above low molecular weight polyols. Examples thereof include oxide adducts and polytetramethylene glycol.

Examples of the polyester polyols include polyols such as the low molecular weight polyols exemplified above, and polyvalent carboxylic acids or their esters, anhydrides, and ester-forming derivatives such as halides in an amount smaller than the stoichiometric amount thereof, and And / or those obtained by a direct esterification reaction and / or transesterification reaction with a lactone or a hydroxycarboxylic acid compound obtained by hydrolytic ring opening thereof. Examples of the polycarboxylic acid include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, 2-methylsuccinic acid, and 2-methyladipic acid. , 3-methyladipic acid, 3-methylpentanedioic acid,
Aliphatic dicarboxylic acids such as 2-methyloctanedioic acid, 3,8-dimethyldecanedioic acid, 3,7-dimethyldecanedioic acid, dimer acid and hydrogenated dimer acid; alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid; Aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid and naphthalene dicarboxylic acid; tricarboxylic acids such as trimellitic acid, trimesic acid and trimer of castor oil fatty acid, and polycarboxylic acids such as tetracarboxylic acid such as pyromellitic acid Examples of the ester-forming derivative thereof include acid anhydrides of these polyvalent carboxylic acids; halides of the polyvalent carboxylic acids such as chloride and bromide; methyl esters, ethyl esters, propyl esters of the polyvalent carboxylic acids. , Isopropyl ester, butyl ester, isobutyl ester, amylue Lower aliphatic esters such as ether can be mentioned. Examples of the lactones include γ-caprolactone, δ-caprolactone, ε-caprolactone, dimethyl-ε-caprolactone, δ-valerolactone, γ
Examples include lactones such as valerolactone and γ-butyrolactone.

When the content (mass%) of the polyhydroxyl compound having an aromatic ring in the component (b) is 10 to 100%, the strength and water resistance of the resulting coating film will be good, which is preferable. -100% is more preferable.

The melamine-based compound (c) according to the present invention is not particularly limited, and well-known general melamine compounds and guanamine compounds used for polyurethane can be used. As the melamine compound, melamine, monomethylol melamine, dimethylol melamine,
Trimethylol melamine, tetramethylol melamine,
Examples include pentamethylol melamine, hexamethylol melamine, methylated methylol melamine, butylated methylol melamine, and melamine resin. Examples of the guanamine compound include guanamine, benzoguanamine, mono- or dimethylol compounds thereof, and guanamine resin. Melamine is preferred because it is particularly excellent in dispersibility of the water-dispersible polyurethane composition and adhesion of the coating film to the substrate.

The silane compound (d) represented by the general formula (I) according to the present invention is hydrolyzable at the terminal of the water-dispersible polyurethane by the reaction of the amino group or NH group of the compound with the isocyanate group. A silyl group and / or a silyl group hydrolyzed by this is introduced.

In the general formula (I), the alkyl having 1 to 8 carbon atoms represented by R is, for example, methyl, ethyl, propyl, isopropyl, butyl, sec-butyl,
Carbons represented by X include tert-butyl, isobutyl, amyl, isoamyl, tert-amyl, hexyl, cyclohexyl, heptyl, isoheptyl, tert-heptyl, n-octyl, isooctyl, tert-octyl, 2-ethylhexyl and the like. Examples of the alkyl groups of the numbers 1 to 4 include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl,
Examples thereof include tertiary butyl and isobutyl. It is preferable that R is methyl or ethyl and X is methyl because it is easily available and at low cost.

As Z, methylene, ethylene,
Propylene, 1-methylethylene, 2-methylethylene, butylene, 1-methylpropylene, 2-methylpropylene and the like can be mentioned, and as R ′, methyl, ethyl,
Propyl, isopropyl, butyl, sec-butyl, octyl, lauryl, stearyl, phenyl, naphthyl, 2-
Methylphenyl, 3-methylphenyl, 4-methylphenyl, 4-vinylphenyl, 3-isopropylphenyl, benzyl, phenethyl, 2-phenylpropane-2
-Yl, diphenylmethyl, triphenylmethyl, styryl, cinnamyl, vinyl, allyl and the like. Preferred are methyl, ethyl, propyl and isopropyl.

Examples of the organic group having an amino group or NH group represented by Ram include the groups represented by the following formulas.

[0028]

[Chemical 5]

(In the formula, R ⁴ is a hydrogen atom, an alkyl group,
It represents a cyclohexyl group or a phenyl group, and R ⁵ represents an alkylene group, a cycloalkanediyl group, an arylene group, a carbonyl group, an alkylenecarbonyl group or a (poly) oxyalkylene group. )

In the above formula, examples of the alkyl group represented by R ⁴ include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, isobutyl, amyl, isoamyl, tert-amyl and the like. Named
Examples of the alkylene group represented by R ⁵ include methylene, ethylene, propylene, methylethylene, butylene, 1-methylpropylene, 2-methylpropylene, 1,2-dimethylpropylene, 1,3-dimethylpropylene and 1-methylbutylene. , 2-methylbutylene, 3-methylbutylene, 4-methylbutylene, 2,4-dimethylbutylene,
1,3-dimethylbutylene, pentylene, hexylene,
Heptylene, octylene and the like, cycloalkanediyl groups include cyclobutane-1,3-diyl, cyclohexane-1,4-diyl and the like, and arylene groups include 1,2-phenylene, 1,3- Phenylene, 1,4-phenylene, 2,5-dimethyl-1,4-
Phenylene, diphenylmethane-4,4'-diyl,
2,2-diphenylpropane-4,4'-diyl and the like, and examples of the alkylenecarbonyl group include groups in which the above-exemplified alkylene group and carbonyl group are bonded,
Examples of the (poly) oxyalkylene group include oxyethylene, polyoxyethylene, oxypropylene, polyoxypropylene and the like.

Further specific examples of the silane compound (d) represented by the general formula (I) include those represented by the following formula.

[0032]

[Chemical 6]

[0033]

[Chemical 7]

(In the formula, R represents the same group as R in the general formula (II).)

The chain extender component (e) containing the dicarboxylic acid dihydrazide compound according to the present invention as an essential component and the diamine compound as an optional component means a dicarboxylic acid dihydrazide compound and a diamine compound optionally used. However, the composition is not particularly limited. Examples of the dicarboxylic acid dihydrazide which is an essential component include compounds of the dicarboxylic acid and hydrazine exemplified as the polyvalent carboxylic acid used in the above polyester polyol. Among them, the aliphatic dicarboxylic acid dihydrazide is preferable because the resulting coating film is less deteriorated by heat and the dispersion stability of the water-dispersible polyurethane composition can be maintained, and the adipic acid dihydrazide is more preferable. If the molar ratio (%) of dicarboxylic acid dihydrazide in the chain extender component is less than 5%, the use effect cannot be obtained, and if it exceeds 95%, the dispersion stability may decrease, so 5 to 95% is preferable. , 10 to 80%
Is more preferable.

Examples of the diamine compound used according to the above need include low molecular weight diamines obtained by substituting the alcoholic hydroxyl groups of the low molecular weight diols exemplified above such as ethylenediamine and propylenediamine with amino groups, and polyoxypropylene. Diamines, polyether diamines such as polyoxyethylenediamine, mensendiamine,
Isophorone diamine, norbornene diamine, bis (4
-Amino-3-methyldicyclohexyl) methane, diaminodicyclohexylmethane, bis (aminomethyl) cyclohexane, 3,9-bis (3-aminopropyl)
Alicyclic diamines such as 2,4,8,10-tetraoxaspiro (5,5) undecane, m-xylenediamine,
α- (m / p-aminophenyl) ethylamine, m-phenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, diaminodiethyldimethyldiphenylmethane, diaminodiethyldiphenylmethane, dimethylthiotoluenediamine, diethyltoluenediamine, α, α′-bis (4 And aromatic diamines such as -aminophenyl) -p-diisopropylbenzene. Among them, low molecular weight diamines are preferable because they are low in cost, and ethylenediamine and propylenediamine are more preferable.

The method for producing the water-dispersible polyurethane composition for coating a chromium-free metal material of the present invention is not particularly limited, and a well-known general method can be applied. As a production method, a prepolymer method in which a prepolymer is synthesized by reacting it in a solvent which is inert to the reaction and has a high affinity for water, and then fed and dispersed in water is preferable. For example, a prepolymer is synthesized from the polyisocyanate component (a), the polyhydroxyl compound component (b) and the melamine compound (c), and this is reacted with the silane compound (d) and the chain extender component (e) in water. Method (a): A prepolymer is synthesized from a polyisocyanate component (a), a polyhydroxyl compound component (b), a melamine compound (c) and a silane compound (d), and this is a chain extender component (e) in water. Method (b) of reacting with a polyisocyanate component (a), polyhydroxyl compound component (b), melamine compound (c), silane compound (d) and chain extender component (e) to synthesize polyurethane, A method (C) of feeding and dispersing the above in water is mentioned.

Of the above production methods, the method (a) or (b) is preferable because the composition and reaction can be easily controlled and good dispersibility can be obtained, and the method (b) is more preferable.

Examples of the solvent which is inert to the reaction and has a high affinity for water used in the above-mentioned preferred production method include:
Acetone, methyl ethyl ketone, dioxane, tetrahydrofuran, N-methyl-2-pyrrolidone and the like can be mentioned. These solvents are usually used in an amount of 3 relative to the total amount of the above-mentioned raw materials used for producing the prepolymer.
~ 100% by weight is used. Of these solvents, those having a boiling point of 100 ° C. or lower are preferably distilled off under reduced pressure after the prepolymer synthesis.

In the above manufacturing method, the compounding ratio is
There is no particular limitation. The compounding ratio can be replaced by the molar ratio of the isocyanate group at the stage of reacting at the time of production and the isocyanate reactive group of each component. Regarding the molar ratio, 1 isocyanate group to 0 isocyanate reactive group 3 to 2 is preferable, and 0.5 to
1.5 is more preferable. Moreover, regarding the compounding ratio of the polyhydroxyl compound component (b), the melamine compound (c), the silane compound (d), and the chain extender component (e), the molar ratio of the polyhydroxyl compound 1 to the melamine compound ( c) is 0.05 to 0.5, the silane compound (d) is 0.01 to 0.3, and the chain extender component (e) is 0.
The range of 01 to 1.0 is preferable.

Further, in the water-dispersed polyurethane composition for non-chromium-treated metal material coating of the present invention, the solid content is
There is no particular limitation, and any value can be selected. The solid content is preferably 1 to 60% by mass because the dispersibility and coatability are good, and more preferably 5 to 40% by mass.

Regarding the silicon content of the solid content of the polyurethane compound according to the present invention, an arbitrary value can be selected by changing the blending of the raw materials.
When the content is less than mass%, the silane group content becomes small, the effect of introducing a sufficient silane group may not be obtained, and the adhesiveness may not be improved, and when it exceeds 5.0 mass%, the dispersion stability of the composition is impaired. Therefore, 0.01 to 5.0 mass% is preferable.

The state of the water-dispersible polyurethane composition of the present invention is an emulsion, suspension, colloidal dispersion, aqueous solution or the like. As a method for obtaining these water-dispersible polyurethane compositions, an ionic method of introducing an anionic group or an ionic group of a cationic group into a polyurethane molecule, a nonionic method of introducing a nonionic group into a polyurethane molecule, and a surfactant Examples of the method include using an emulsifier such as an agent, and two or more of these may be used in combination.

As the above-mentioned ionic method, for example, a method of introducing an ionic group into the polyhydroxyl compound component (b) by using an ionic group-introduced polyol and neutralizing this with a neutralizing agent is easy and cost-effective Is also preferable because it is small. The amount of the polyol used to introduce the ionic group is
It is not particularly limited and can be appropriately selected. When the amount of the ionic group-introduced polyol compound is less than 1 in the total polyhydroxyl compound component (b) 100 in terms of molar ratio, the dispersion stability is lowered, and when it is more than 90, it is obtained from the water-dispersible polyurethane composition. Since the water resistance of the coating film and the like to be obtained may deteriorate, 1 to 90 is preferable, and 5 to 75 is more preferable.

The above-mentioned ionic group-introduced polyols include those that introduce an anionic group, for example, polyols containing a carboxyl group such as dimethylolpropionic acid, dimethylolbutanoic acid, dimethylolbutyric acid, and dimethylolvaleric acid. 1,4-butanediol-2-
Examples thereof include polyols containing a sulfonic acid group such as sulfonic acid, and examples of introducing a cationic group include N, N-dialkylalkanolamines, N-methyl-N, N-diethanolamine and N-butyl. -N,
Examples thereof include N-alkyl-N, N-dialkanolamines such as N-diethanolamine and trialkanolamines.

Examples of the anionic group neutralizing agent used in the above ion method include trialkylamines such as trimethylamine and triethylamine, N, N-dialkylalkanolamines, N-alkyl-N, N-dialkanols. 3 such as amines and trialkanol amines
Basic compounds such as secondary amines, ammonia, sodium hydroxide, potassium hydroxide, lithium hydroxide and the like can be mentioned. As the cationic group neutralizing agent, formic acid, acetic acid, lactic acid, succinic acid, glutaric acid, citric acid, etc. Organic carboxylic acids, paratoluene sulfonic acid, organic sulfonic acids such as alkyl sulfonate, hydrochloric acid, phosphoric acid, nitric acid, inorganic acids such as sulfonic acid,
In addition to epoxy compounds such as epihalohydrin, quaternizing agents such as dialkyl sulfuric acid and alkyl halides can be used. When the amount of these neutralizing agents used is too large or small with respect to 1 mol of the ionic group, physical properties such as water resistance, strength and elongation of the coating film obtained from the water-dispersible polyurethane composition are deteriorated. Therefore, 0.5 to 2.0 mol is preferable because
0.8-1.5 mol is more preferable.

The above nonionic method is a method of imparting water dispersibility by introducing a nonionic hydrophilic group such as an oxyethylene chain into the main chain or side chain of a polyurethane molecule. The hydrophilic group can be introduced by a method of incorporating a required amount of oxyethylene chain into the side chain and / or main chain of the urethane prepolymer.

As the above-mentioned emulsifier, well-known general anionic surfactants, nonionic surfactants, cationic surfactants, amphoteric surfactants, polymer surface active agents used in water-dispersible polyurethanes are used. Agents, reactive surfactants and the like can be used. Among them, anionic surfactants, nonionic surfactants or cationic surfactants are preferable because they are low in cost and good emulsification can be obtained.

Examples of the above-mentioned anionic surfactants include alkylsulfates such as sodium dodecyl sulfate, potassium dodecyl sulfate and ammonium dodecyl sulfate; sodium dodecyl polyglycol ether sulfate; sodium sulforicinolate; alkali metal of sulfonated paraffin. salt,
Alkyl sulfonates such as ammonium salts of sulfonated paraffins; fatty acid salts such as sodium laurate, triethanolamine oleate and toluethanolamine abiate; alkyl aryl sulfonates such as sodium benzene sulfonate and alkali metal sulphates of alkali phenol hydroxyethylene; high alkyl Naphthalene sulfonate; naphthalene sulfonic acid formalin condensate; dialkyl sulfosuccinate; polyoxyethylene alkyl sulfate salt; polyoxyethylene alkyl aryl sulfate salt and the like.

Examples of the above nonionic surfactants include ethylene oxide of alcohol having 1 to 18 carbon atoms and /
Or, a propylene oxide adduct, an ethylene oxide and / or a propylene oxide adduct of an alkylphenol, an ethylene oxide and / or a propylene oxide adduct of an alkylene glycol and / or an alkylenediamine, and the like can be mentioned.

Examples of the alcohol having 1 to 18 carbon atoms which constitutes the above nonionic surfactant include methanol, ethanol, propanol, 2-propanol, butanol, 2-butanol, tert-butanol, amyl alcohol, isoamyl alcohol, Examples include triamyl alcohol, hexanol, octanol, decane alcohol, lauryl alcohol, myristyl alcohol, palmityl alcohol, stearyl alcohol, and the like. As alkylphenol, phenol, methylphenol,
2,4-di-tert-butylphenol, 2,5-di-tert-butylphenol, 3,5-di-tert-butylphenol, 4-
(1,3-Tetramethylbutyl) phenol, 4-isooctylphenol, 4-nonylphenol, 4-tertiary octylphenol, 4-dodecylphenol, 2-
(3,5-Dimethylheptyl) phenol, 4- (3,3
5-dimethylheptyl) phenol, naphthol, bisphenol A, bisphenol F, and the like, and examples of the alkylene glycol include ethylene glycol, 1,2.
-Propanediol, 1,3-propanediol, 2-
Methyl-1,3-propanediol, 2-butyl-2-
Ethyl-1,3-propanediol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 2,
4-diethyl-1,5-pentanediol, 1,6-hexanediol and the like can be mentioned, and examples of the alkylenediamine include those in which the alcoholic hydroxyl group of these alkylene glycols is substituted with an amino group. Also,
The ethylene oxide and propylene oxide adduct may be a random adduct or a block adduct.

As the above-mentioned cationic surfactant, 1
Examples include primary to tertiary amine salts, pyridinium salts, and quaternary ammonium salts.

The amount of these emulsifiers to be used is not particularly limited, and any amount can be used, but if the weight ratio to the polyurethane compound 1 is less than 0.01, sufficient dispersibility can be obtained. It may not be possible, and 0.
If it exceeds 3, the physical properties such as water resistance, strength and elongation of the coating film obtained from the water-dispersible polyurethane composition may deteriorate, so 0.01 to 0.3 is preferable, and 0.05 to 0.3 is preferable.
0.2 is more preferable.

The dispersion method for obtaining the above water-dispersible polyurethane composition is appropriately selected depending on other components such as a rust preventive added to the chromium-free metal coating material. The anion method, in which an anionic group is introduced into the polyurethane molecule, is preferable because it has a good compatibility with the commonly used chromium-free anticorrosive agent.

Various well-known and commonly used additives may be used in the water-dispersible polyurethane composition of the present invention, if necessary. Examples of the additives include pigments, dyes, film-forming aids, curing agents, coupling agents, antiblocking agents, viscosity modifiers, leveling agents, defoamers, gelation inhibitors, dispersion stabilizers, and light stabilizers. Agents, antioxidants, ultraviolet absorbers, radical scavengers, heat resistance imparting agents, inorganic and organic fillers, plasticizers, lubricants, antistatic agents, reinforcing agents, catalysts, thixotropic agents, antibacterial agents, antifungal agents, Examples include antiseptic agents and hydrolyzable silyl group stabilizers. Further, when particularly strong adhesion to the substrate is required, colloidal silica, tetraalkoxysilane and its polycondensation product may be used.

The water-dispersible polyurethane composition of the present invention comprises
It is used for non-chromium non-chromium paints. Etching-based fluorides such as zinc fluoride, zinc hexafluorosilicate and hydrates thereof and rust preventives may be used in the paint, and it is preferable to contain a rust preventive. Examples of the rust preventive agent include phosphoric acid compounds,
Vanadium-based compounds, those obtained by firing and pulverizing a mixture containing one or both of a network-modifying ion source and a glass-like substance, Mg ₂ Si alloy powder having a surface plated, molybdate-based compounds And boric acid compounds such as barium metaborate.

Examples of the above phosphoric acid compounds include orthophosphoric acid, condensed phosphorus, orthophosphates or condensed phosphates of various metals, phosphorus pentoxide, phosphate minerals, commercially available complex phosphate pigments, and phosphoric acid. Ammonium or mixtures thereof may be mentioned. The orthophosphates mentioned here include monohydrogen salts (salts of HPO ₄ ^2- ) and dihydrogen salts (H ₂ P).
O ₄ ^- salt) including. The condensed phosphate also contains a hydrogen salt. The condensed phosphate also includes metaphosphate, and includes ordinary polyphosphate and polymetaphosphate. Specific examples of the phosphorus compound include phosphate minerals such as monetite, toluphyrite, witlockite, xenotime, starcolite, struvite, oranite, and commercially available complex phosphate pigments such as polyphosphate silica. , Complex phosphoric acid, such as pyrophosphoric acid, metaphosphoric acid, and complex phosphate, such as metaphosphate, tetrametaphosphate, hexametaphosphate, pyrophosphate, acidic pyrophosphate, tripolyphosphate, or mixtures thereof. Is mentioned. The metal species forming the phosphate is not particularly limited, and alkali metal,
Examples thereof include alkaline earth metals, metal species of other typical elements, and transition metals. Examples of preferred metal species include magnesium, calcium, strontium, barium,
Examples thereof include titanium, zirconium, manganese, iron, cobalt, nickel, zinc, aluminum, lead and tin.
In addition to these, oxo cations such as vanadyl, titanyl and zirconyl are also included, and calcium and magnesium are particularly preferable.

As the vanadium compound,
Vanadium is a compound having a valence of 0, 2, 3, 4 or 5 or two or more thereof, and these oxides, hydroxides, oxyacid salts of various metals, vanadyl compounds, halides, Examples thereof include sulfate and metal powder.
Among them, those containing a pentavalent vanadium compound as one component are preferable. Specific examples of the vanadium compound include vanadium oxide (II), vanadium hydroxide (II),
Vanadium (III) oxide, vanadium (IV) oxide, vanadyl halide, vanadium (V) oxide, orthovanadate of various metals, metavanadate or pyrovanadate, vanadyl halide, ammonium vanadide, or these A mixture may be mentioned. The metal species of vanadate may be the same as those shown for phosphate.

Examples of the chromium-free metal material according to the present invention include hot-rolled steel sheet, cold-rolled steel sheet, galvanized steel sheet, hot-dip galvanized steel sheet, galvannealed steel sheet,
Zinc alloy plated steel sheet, aluminum plated steel sheet, nickel plated steel sheet, copper plated steel sheet, zinc nickel plated steel sheet, zinc aluminum plated steel sheet, zinc iron plated steel sheet, tin plated steel sheet, and other plated steel sheets, stainless steel sheet, aluminum sheet, copper sheet, aluminum sheet Examples include alloy plates.

[0060]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. The abbreviations of the raw materials used are shown below. (Polyisocyanate) HMDI: Dicyclohexylmethane diisocyanate IPDI: Isophorone diisocyanate (polyhydroxyl compound) MPD / TPA: Polyester polyol of 3-methyl-1,5-pentanediol and terephthalic acid 1,6HD / TPA: 1,6-hexanediol / Polyester polyol of terephthalic acid 1,6HD / AA / IPA: 1,6-hexanediol, adipic acid and isophthalic acid (AA / IPA = 1/1 molar ratio) polyester polyol BPX (trade name: Asahi Denka Kogyo Co., Ltd.) Made by: propylene oxide adduct of bisphenol A, BPX
(Average molecular weight 360) is a 2 mol adduct of propylene oxide (about p = q = 1 in formula (II)), and BPX (average molecular weight 790) is an adduct of 10 mol of propylene oxide (about p = q = in formula (II)). 5) MPD / AA: polyester polyol PPG of 3-methyl-1,5-pentanediol and adipic acid PPG: polypropylene glycol (number average molecular weight 1,
000) (melamine compound) MM: melamine (silane compound) AS-1: γ-aminopropyltriethoxysilane AS-2: γ-aminopropyldiethoxymethylsilane (chain extender) EDA: ethylenediamine ADH: adipic dihydrazide ( Ionic group-introducing compound) DMPA: Dimethylolpropionic acid (neutralizing agent) TEA: Triethylamine

The water-dispersible polyurethane composition was evaluated as follows. (Adhesion evaluation) A steel plate not subjected to chromium treatment was coated with a water-dispersible polyurethane composition with a bar coater at 3 g / m ² and heated at 220 ° C. for 20 seconds to obtain a test piece with the coated surface facing outside. 180 degreeC bending processing was performed. The coating film of the processed portion was evaluated by observing cracks with a magnifying glass and pressing the cellophane tape and then peeling the coating film when the cellophane tape was peeled off. The appearance score criteria are as follows. ◯: No cracking or peeling. Δ: There is a crack. X: There is peeling. (Ethanol resistance evaluation) A cold rolled steel sheet not subjected to chromium treatment was coated with a bar coater at 3 g / m ² and heated at 220 ° C. for 20 seconds.
The rubbing was carried out with 20 reciprocations of cm ² and the coating film was evaluated by appearance. The appearance score criteria are as follows. 5: No change in appearance. 4: There is gloss on the surface. 3: There is stickiness on the surface. 2: There is peeling. 1: Melt or peel. (Evaluation of alkali resistance) 3 g / m ² was applied to a cold-rolled steel sheet not subjected to chrome treatment with a bar coater, and the temperature was 2 at 220 ° C.
The test piece obtained by heating for 0 second was immersed in a 2 mass% ammonium phosphate solution at 50 ° C. for 5 minutes to evaluate the coating film. The appearance score criteria are as follows. 5: No change in appearance. 4: Surface discoloration. 3: Surface melted. 2: There is peeling. 1: Total peeling or total dissolution.

[Manufacturing Example] Manufacture of Urethane Prepolymer By blending as shown in Tables 1 and 2, polyhydroxy compound component, polyisocyanate component, melamine compound: M
M, ionic group-introducing compound: DMPA, N-methyl-2
-Pyrrolidone (the amount of N-methyl-2-pyrrolidone is 30% by mass of the total reaction mass) and a silane compound were charged into a reaction flask, and the mixture was reacted under a nitrogen stream at 125 ° C for 2 hours and then neutralized. Agent; TEA was added, and the mixture was further stirred for 1 hour to obtain prepolymers PP-1 to PP-13 (Table 1) and prepolymers PP-14 to PP-17 (Table 2).

[0063]

[Table 1]

[0064]

[Table 2]

[Example 1] SE-2 silicone antifoaming agent
545 in which 0.2 g of 1 (manufactured by Wacker Silicone) was dissolved
400 g of PP-2 obtained above was added dropwise to 15 g of water in 15 minutes. Then, ethylenediamine and adipic acid hydrazide (ethylenediamine / adipic acid hydrazide (molar ratio) 1/4) were added as a chain extender component, and the mixture was stirred at 25 ° C for 30 minutes to obtain a water-dispersed polyurethane composition PU-1. In all Examples and Comparative Examples, the ratio of the number of moles of isocyanate-reactive groups in the chain extender component to the number of moles of isocyanate groups in the prepolymer was almost the same.
Excessive value is set.

Comparative Example 1 PP-14 instead of PP-2
The same procedure as in Example 1 was repeated except that Nos. 16 to 16 were used, and Comparative P, which was a comparative water-dispersed polyurethane composition, was used.
U-1 to 3 were obtained. Also, instead of PP-2, PP-2,
Comparative PU-4 to 7 were obtained in the same manner as in Example 1 except that the chain extender component was changed to ethylenediamine using 14, 15, and 16.

The above water-dispersible polyurethane composition was applied to a cold-rolled steel sheet that had not been treated with chromium and evaluated.
The results of comparison and evaluation of the components of Example 1 and Comparative Example 1 are shown in Table 3.
Shown in.

[0068]

[Table 3]

[Embodiment 2] PP-6 to PP-6 instead of PP-2
Water-dispersed polyurethane compositions PU-2 to 4 were obtained in the same manner as in Example 1 except that No. 8 was used.

[Comparative Example 2] PP-17 was used instead of PP-2.
Comparative PU-8, which is a water-dispersible polyurethane composition for comparison, was obtained by the same operation as in Example 1 except that was used. Comparative PU-9 was obtained by the same procedure as in Example 1 except that PP-17 was used instead of PP-2 and the chain extender component was changed to ethylenediamine.

The above water-dispersible polyurethane composition was applied to an electrogalvanized steel sheet not treated with chromium and evaluated. Table 4 shows the comparison and evaluation results of the components of Example 2 and Comparative Example 2.

[0072]

[Table 4]

Example 3 Water-dispersible polyurethane composition PU-was prepared in the same manner as in Example 1 except that urethane prepolymers shown in Table 5 were used instead of PP-2.
5-12 were obtained.

The above water-dispersible polyurethane composition was applied to an electrogalvanized steel sheet not treated with chromium and evaluated. The results of comparison and evaluation of the components of Example 3 are shown in Table 5.

[0075]

[Table 5]

[0076]

INDUSTRIAL APPLICABILITY The present invention can provide a water-dispersible polyurethane composition suitable for a chromium-free metal coating material, which provides adhesion to a substrate, alkali resistance and solvent resistance.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4J034 BA08 CA03 CA11 CA12 CA15                       CA17 CB02 CB03 CB04 CB05                       CC03 CC35 CD15 CE01 DA01                       DB03 DG02 HA01 HA07 HB08                       HC03 HC12 HC13 HC35 RA07                 4J038 DA161 DA162 DA171 DA172                       DG111 DG112 DG271 DG272                       DG301 DG302 DL081 DL082                       GA06 GA09 JB17 JC30 KA03                       KA05 KA09 LA02 NA04 NA12                       NA27 PA20 PC02

Claims (7)

[Claims] 1. A polyisocyanate component (a) comprising an alicyclic polyisocyanate as an essential component and another polyisocyanate compound as an optional component, and a polyhydroxyl compound having an aromatic ring as an essential component, and another polyisocyanate compound. A polyhydroxyl compound component (b) containing a hydroxyl compound as an optional component, a melamine compound (c), a silane compound (d) represented by the following general formula (I), and a dicarboxylic acid dihydrazide compound as essential components, and a diamine. A water-dispersible polyurethane composition for a chromium-free metal coating material obtained from a chain extender component (e) containing a compound as an optional component and water. [Chemical 1] (In the formula, X represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, l represents 0 or 1, n represents 1, 2 or 3, and R represents 1 to 8 carbon atoms. Represents an alkyl group, Ram
Represents an organic group having an amino group or an NH group, and Y represents
Single bond, -O-, -S-, -N-, -NH-, -NR '
Represents-, Z represents an alkylene group having 1 to 4 carbon atoms, and m
Y is a single bond, -O-, -S-, -NH-, -NR '.
In the case of-, 1 is represented, in the case of Y being -N-, 2,
R'represents an organic group having 1 to 18 carbon atoms. ) 2. The water dispersion for a chromium-free metal coating material according to claim 1, wherein the content of the polyhydroxyl compound containing an aromatic ring in the polyhydroxyl compound component (b) is 10 to 100% by mass. -Type polyurethane composition. 3. The water-dispersible polyurethane composition for non-chromium-treated metal material coating according to claim 1, wherein the polyhydroxyl compound having an aromatic ring is a polyester diol obtained from an aromatic dicarboxylic acid and a low molecular weight diol. 4. The water-dispersible polyurethane composition for a chromium-free metal coating material according to claim 1 or 2, wherein the polyhydroxyl compound having an aromatic ring is a compound represented by the following general formula (II). [Chemical 2] (In the formula, R ¹ and R ² are each a hydrogen atom or a carbon number of 1 to 4;
Represents an alkyl group, A represents an alkylene group having 2 to 4 carbon atoms, and p and q represent 1 to 10. ) 5. The water-dispersible polyurethane composition for a chromium-free metal coating composition according to claim 1, wherein the polyhydroxyl compound component (b) contains an anionic group-introduced polyol. 6. A polyisocyanate component (a), a polyhydroxyl compound component (b), a melamine compound (c), a silane compound (d) and a chain extender component (e) as set forth in claim 1 are used. A method for producing a water-dispersible polyurethane composition for a non-chromium-treated metal coating by the following method (a), (b) or (c). A method of synthesizing a prepolymer from a polyisocyanate component (a), a polyhydroxyl compound component (b) and a melamine compound (c), and reacting this with a silane compound (d) and a chain extender component (e) in water ( A); a prepolymer is synthesized from the polyisocyanate component (a), the polyhydroxyl compound component (b), the melamine compound (c) and the silane compound (d), and this is reacted with the chain extender component (e) in water. Method (b): a polymer is synthesized from the polyisocyanate component (a), the polyhydroxyl compound component (b), the melamine compound (c), the silane compound (d) and the chain extender component (e), and this is prepared in water. How to feed and disperse in (c). 7. A prepolymer is synthesized from a polyisocyanate component (a), a polyhydroxyl compound component (b), a melamine compound (c) and a silane compound (d), and this is prepared in water by a chain extender component (e). The manufacturing method according to claim 6, which is reacted with