JP5264363B2 - Surface treatment metal material and metal surface treatment agent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal surface treatment agent that solves problems of corrosion resistance, corrosion resistance after processing, adhesion of a finish coat painting, alkali resistance and solvent resistance by finding a polyurethane resin structure and an additive that can derive polyurethane resin characteristics to the utmost as the surface treatment agent substitutable for chromate treatment, and to provide a surface-treated metal material. <P>SOLUTION: This surface treatment agent includes polyurethane resin that contains a functional group (a) represented by general formula [1] (wherein R1, R2 and R3 are each independently alkoxy or hydroxy), and silicon oxide. The polyurethane resin further can contain a specific functional group (b) and a urea bond. The total amount of the functional groups (a) and (b), and the silicon oxide is within a specific range. The surface treatment agent can contain a specific crosslinking agent. The surface treated metal material is manufactured by coating the surface treatment agent on the surface of the metal material, baking and drying it. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a surface-treated metal material and metal surface-treating agent that do not contain hexavalent chromium, which has high environmental impact, and have extremely high corrosion resistance and post-processing corrosion resistance, as well as good topcoat paint adhesion, solvent resistance, and alkali resistance. It is about.

  In various fields such as home appliances, automobiles, and building materials, it is common to perform chromate treatment on steel sheets and surface-treated steel sheets for the purpose of imparting rust prevention or paint adhesion to the upper layer. However, since the chromate-treated film usually contains hexavalent chromium having a high environmental load, in recent years, there has been an increasing demand for this hexavalent chromium-free (hereinafter referred to as chromate-free). Some industries are moving toward complete abolition.

For these flows, various surface treatment methods not containing chromium have been devised.
Regarding a film mainly composed of an inorganic compound, for example, Patent Document 1 discloses a method of treating with a treatment liquid containing orthophosphoric acid, aluminum-based sol, and metal-based hydrosol, and Patent Document 2 discloses water glass, sodium silicate, and pyrazole. Patent Document 3 discloses a method of performing silicate coating.
However, such an inorganic film has a problem that wrinkles are easily generated during processing and molding, and the adhesiveness with the top coating is inferior, so that its application is limited. Further, for example, the corrosion resistance against sodium chloride has not yet been sufficiently satisfactory for chromate treatment.

  On the other hand, several coatings that can replace chromate coatings mainly composed of organic coatings have been studied. A film mainly composed of an organic compound has a feature of excellent formability in addition to the effect of blocking the corrosive environment by the film, and is promising as a chromate-free film. Among these, a film mainly composed of a polyurethane resin having tough properties as a film and good adhesion is particularly promising as a chromate-free film.

  So far, several techniques based on polyurethane resins have been disclosed. For example, Patent Document 4 discloses a technique of providing a film layer mainly composed of a composite material or mixed material of polyurethane resin and silicon dioxide as an example of excellent film adhesion after processing. Patent Document 5 discloses a technique for providing a resin film containing colloidal silica or a silane coupling agent and a specific metal phosphate on a polyurethane resin as an example of a film excellent in electrodeposition and weldability. Document 6 discloses a technique of a treatment liquid in which an aqueous polyurethane resin and an oxycarboxylic acid compound are mixed with a metal phosphate.

  However, as the use of such a polyurethane resin-based coating spreads to various applications, the required characteristics are becoming stricter. In the case of the techniques described in Patent Documents 4 to 6, the polyurethane resin described However, the resin structure has not been fully studied, and there is a concern that it will be difficult to ensure strict performance such as corrosion resistance after processing, solvent resistance, alkali resistance, etc. There is a concern that the solvent resistance cannot be sufficiently obtained and the solvent resistance is lowered.

  Moreover, as an example for the purpose of imparting rust prevention, Patent Document 7 discloses a film technology in which a silane coupling agent is added to a polyurethane resin into which a hydrophilic component is introduced, and Patent Document 8 discloses an aqueous polyurethane resin and an aqueous polyolefin resin. The technology of a rust preventive coating agent in which aqueous silica, a silane coupling agent, a thiocarbonyl group-containing compound, and a phosphate ion are mixed in a mixture of the above, Patent Document 9, and one or more types of silane coupling or a partially hydrolyzed condensate thereof, The technology of an aqueous coating composition mainly composed of an organic-inorganic composite resin aqueous dispersion containing a polyurethane resin containing a hydrolyzable silyl group or silanol group, Patent Document 10 discloses a reaction between an aqueous polyurethane resin and a silane coupling agent. The technique of the film | membrane containing the crosslinked resin matrix and inorganic rust preventive agent which were formed by this is disclosed.

  However, the techniques described in Patent Documents 7 to 10 also have a concern that it is difficult to ensure strict performance because the structure of the resin is not sufficiently studied as in Patent Document 4. Further, in the techniques of Patent Documents 7 to 10, since the silane coupling agent is mixed in the treatment agent, the reactivity of the treatment agent is unstable, and the performance depends on the production conditions, the time after production, and the influence of the environment. There was concern that it would vary. In addition, there is a problem that there is a concern that the solvent resistance necessary for wiping off dirt with a solvent may be inferior because neither of them can stably provide a sufficient crosslinking reaction.

  Patent Documents 11 to 13 disclose a coating technique in which a crosslinking agent is added to a polyurethane resin containing a silanol group and / or a siloxane bond in the molecule. However, the technology is that the reactivity of the treating agent is stable, but the structure design of the silanol group and / or siloxane bond, the design of the polyurethane resin structure, the cross-linking considering the corrosion resistance, solvent resistance, alkali resistance and other characteristics. Since additives such as additives and rust preventives are not designed, there is a concern that the performance as a rust preventive film will not be sufficiently exhibited.

Japanese Examined Patent Publication No. 53-47774 Japanese Patent Publication No.58-31390 JP-A-4-293789 Japanese Patent Publication No. 6-7950 Japanese Patent Publication No. 6-71579 JP 2001-181855 A JP 2001-59184 A JP 2001-164182 A JP 2003-147266 A JP 2005-281863 A Japanese Patent Laid-Open No. 2007-075777 JP 2007-038652 A JP 2008-025023 A

  Therefore, the present invention focuses on polyurethane resin as a component of a surface treatment agent that can be substituted for chromate treatment, and finds a polyurethane resin structure and additives that exhibit their characteristics to the maximum, thereby providing a highly environmentally friendly hexavalent chromium. In addition, the present invention provides a metal surface treating agent that can sufficiently withstand use in an actual environment by solving various problems such as corrosion resistance and post-processing corrosion resistance, top coating adhesion, solvent resistance, and alkali resistance. It aims at providing the surface treatment metal material obtained by apply | coating an agent and drying.

（式中、Ｒ１、Ｒ２及びＲ３は互いに独立に、アルコキシ基又は水酸基を表す。） In view of such problems, the present inventors have studied in detail the effects of the polyurethane resin structure and additives on the above-mentioned corrosion resistance and post-processing corrosion resistance, topcoat adhesion, solvent resistance, and alkali resistance of metal surface treatment agents. did.
As a result, in a practical environment, a polyurethane resin containing a functional group (a) represented by the following general formula [1] in the molecule and silicon oxide are mixed to form a metal surface treatment agent. It becomes a stable metal surface treatment agent without gelation, and when the treatment agent is baked and dried, a good crosslinking reaction can be obtained and a tough film can be formed. Excellent corrosion resistance and post-processing corrosion resistance, adhesion to top coating The present inventors have found that a surface-treated metal material that exhibits high resistance, solvent resistance, and alkali resistance can be obtained.

(In the formula, R1, R2 and R3 each independently represents an alkoxy group or a hydroxyl group.)

  Due to the alkoxy group or hydroxyl group contained in the functional group (a), the plurality of functional groups (a) may condense in the baking and drying process (form a siloxane bond) to give a crosslinked structure in the film. Is possible. As a result, it is possible not only to increase the crosslink density of the resin, but also to improve the film-forming property of the film, and to prevent rusting of the film (blocking effect of corrosive factors such as oxygen and water), alkali resistance and resistance. Various performances such as solvent resistance can be improved.

Similarly, the surface hydroxyl group of silicon oxide and the alkoxy group or hydroxyl group contained in the functional group (a) can form a siloxane bond, and the cross-linked structure of the film can be imparted more efficiently, and the corrosion resistance and adhesion are improved. be able to.
In addition, by adding silicon oxide, the toughness of the film itself can be increased, and the solvent resistance and alkali resistance of the film can be improved.
Furthermore, the surface hydroxyl group of the base metal and the alkoxy group or hydroxyl group contained in the functional group (a) form a bond, and the effect of improving the adhesion between the film and the base metal material can be obtained.

  In addition, by incorporating the functional group (a) in the molecule of the polyurethane resin, it is possible to improve the water dispersibility of the emulsion in water and make it a stable metal surface treatment agent that does not gel in a practical environment. It is. The functional group (a) containing three alkoxy groups or hydroxyl groups is selected from the siloxane bond between the plurality of functional groups (a), the siloxane bond with the surface hydroxyl group of silicon oxide, and the bond with the surface hydroxyl group of the base metal. Any one of the bonds can be formed at the maximum, the reaction rate of the bonds is excellent, and the water dispersibility is the best.

（式中、Ｒ４は水素原子、アルキル基、アリール基及びアラルキル基からなる群より選ばれる一価の有機残基、Ｒ５及びＲ６は互いに独立に、アルコキシ基又は水酸基を表す。） In addition, by further containing the functional group (b) represented by the following general formula [2] in the molecule of the polyurethane resin, various performances are further improved. It has been found that corrosion resistance can be obtained after processing.

(Wherein R4 represents a monovalent organic residue selected from the group consisting of a hydrogen atom, an alkyl group, an aryl group and an aralkyl group, and R5 and R6 each independently represents an alkoxy group or a hydroxyl group.)

  Similarly to the functional group (a), the functional group (b) is any one selected from a siloxane bond between the plurality of functional groups (a), a siloxane bond with the surface hydroxyl group of silicon oxide, and a bond with the surface hydroxyl group of the base metal. By forming a bond and improving water dispersibility, the corrosion resistance and post-processing corrosion resistance, adhesion of top coating, solvent resistance, and alkali resistance of the metal material are further improved. In particular, the functional group (b) causes steric hindrance due to the monovalent organic residue contained therein, and the reaction for forming the bond proceeds more slowly than the functional group (a). Even if it makes it, the outstanding stability can be ensured, and also after a crosslinking reaction, it is comparatively rich in flexibility, and can improve the corrosion resistance after processing of a film.

  Furthermore, the amount of the functional group (a), the amount of the functional group (b), the total amount of silicon oxide, the amount of urea bond, and the total amount of urethane bond contained in the molecule of the polyurethane resin are respectively appropriate. By designing the amount, it is possible to obtain a tough film excellent in corrosion resistance, alkali resistance, and solvent resistance, adhesion to a metal material and a top coating, and a well-balanced film including them even after processing.

  Further, by introducing an organic titanate as an additive for the metal surface treatment agent, in addition to the crosslinking reaction derived from the functional group (a), (b) or silicon oxide, a crosslinking reaction may be caused, The speed of the cross-linking reaction can be increased, and the film can be formed at a lower baking temperature, and a good film can be obtained in all of the corrosion resistance and post-processing corrosion resistance, top coating adhesion, solvent resistance, and alkali resistance. It is.

  In addition, in order to disperse the polyurethane resin in water, an appropriate amount of a carboxyl group is further contained in the molecule, and self-emulsification is performed using a specific neutralizing agent at the time of water dispersion, and a specific cross-linking agent is added as an additive. A surface-treated metal material having a film formed by applying a metal surface treatment agent obtained by containing a polyolefin resin in a certain ratio to a specific steel plate and drying it has extremely high corrosion resistance, post-processing corrosion resistance, and top coating. It has been found that it has paint adhesion, alkali resistance, and solvent resistance, and has completed the present invention.

（式中、Ｒ１、Ｒ２及びＲ３は互いに独立に、アルコキシ基又は水酸基を表す。）

（式中、Ｒ４は水素原子、アルキル基、アリール基及びアラルキル基からなる群より選ばれる一価の有機残基、Ｒ５及びＲ６は互いに独立に、アルコキシ基又は水酸基を表す。） That is, the gist of the present invention is as follows.
(1) It contains a polyurethane resin containing a functional group (a) represented by the following general formula [1] and a functional group (b) represented by the following general formula [2] in the molecule, and silicon oxide. Characteristic metal surface treatment agent.

(In the formula, R1, R2 and R3 each independently represents an alkoxy group or a hydroxyl group.)

(Wherein R4 represents a monovalent organic residue selected from the group consisting of a hydrogen atom, an alkyl group, an aryl group and an aralkyl group, and R5 and R6 each independently represents an alkoxy group or a hydroxyl group.)

( 2 ) The total amount of silicon derived from the functional group (a), silicon derived from the functional group (b), and silicon derived from the silicon oxide is expressed by the following formula with respect to the total mass of the nonvolatile solid content. The metal surface treatment agent according to (1 ), which is in a range.
1.6% by mass ≦ ((Sa + Sb + Sc) / S) × 100 ≦ 25% by mass
Where S: total mass of non-volatile solids
Sa: Mass of silicon derived from the functional group (a)
Sb: Mass of silicon derived from the functional group (b)
Sc: Mass of silicon derived from silicon oxide

( 3 ) The polyurethane resin contains a urea bond in the molecule, and the total amount of nitrogen derived from the urea bond and nitrogen derived from the urethane bond is the following with respect to the mass of the nonvolatile solid content of the polyurethane resin: The metal surface treating agent according to (1) or (2) , wherein the metal surface treating agent is in a range represented by a mathematical formula.
0.1% by mass ≦ (Ta + Tb) / T) × 100 ≦ 10% by mass
Where T: mass of nonvolatile solid content of polyurethane resin Ta: mass of nitrogen forming urea bond (—NH—CO—NH—) Tb: mass of nitrogen forming urethane bond (—NH—CO—O—) mass

( 4 ) The metal surface treating agent as set forth in any one of (1) to ( 3 ), which contains an organic titanate compound as a crosslinking agent for the polyurethane resin.
( 5 ) The metal surface treating agent according to any one of (1) to ( 4 ), wherein the polyurethane resin is water-dispersible or water-soluble and contains a carboxyl group in the molecule.
( 6 ) The metal surface treating agent according to ( 5 ), wherein the polyurethane resin has an acid equivalent of 1000 to 3000.
( 7 ) The metal surface treatment agent according to ( 5 ) or ( 6 ), wherein the boiling point of the neutralizing agent when the polyurethane resin is dispersed in water is 150 ° C. or less.
( 8 ) The metal surface according to any one of ( 5 ) to ( 7 ), wherein the neutralizing agent at the time of water dispersion of the polyurethane resin is at least one selected from alkylamines and alkanolamines. Processing agent.
( 9 ) The metal surface treating agent according to any one of ( 5 ) to ( 8 ), further comprising a carbodiimide compound or an oxazoline group-containing compound as a crosslinking agent for the polyurethane resin.
( 10 ) The metal surface treatment agent according to any one of (1) to ( 9 ), further comprising a polyolefin resin in an amount of 5% by mass to 50% by mass with respect to the total amount of nonvolatile solids.

( 11 ) A surface treatment method for a metal material, wherein the metal surface treatment agent according to any one of (1) to ( 10 ) is applied to the surface of the metal material and dried to form a film.

( 12 ) A surface-treated metal material comprising a film formed by using the surface treatment method according to claim ( 11 ).
( 13 ) The surface-treated metal material according to ( 12 ), wherein the metal material is a zinc-based plated steel plate or an aluminum-based plated steel plate.

  ADVANTAGE OF THE INVENTION According to this invention, the metal surface treating agent for obtaining the membrane | film | coat which combines the performance which does not use the hexavalent chromium with a high environmental load at all, and can replace conventional chromate also in performance can be provided. Therefore, the present invention is very promising as a future environmentally-friendly treatment agent and greatly contributes to each industrial field.

  Hereinafter, embodiments for carrying out the present invention will be described in detail.

（式中、Ｒ１、Ｒ２及びＲ３は互いに独立に、アルコキシ基又は水酸基を表す。） The metal surface treatment agent of the present invention contains a polyurethane resin and silicon oxide, and the polyurethane resin contains a functional group (a) represented by the following general formula [1] in the molecule.

(In the formula, R1, R2 and R3 each independently represents an alkoxy group or a hydroxyl group.)

The polyurethane resin is obtained by reacting an active hydrogen group-containing compound (A) having at least one functional group (a) in the molecule with a polyurethane prepolymer, and then dispersing or dissolving in water and hydrolyzing. Can be formed. The polyurethane prepolymer can be obtained by reacting a compound (C) having at least two active hydrogen groups per molecule with a compound (D) having at least two isocyanate groups per molecule.
Alternatively, the active hydrogen group-containing compound (A) having at least one functional group (a) in the molecule, the compound (C) having at least two active hydrogen groups per molecule, and at least 2 per molecule. You may react with the compound (D) which has an isocyanate group simultaneously.

  Examples of the active hydrogen group-containing compound (A) having at least one functional group (a) in the molecule include γ- (2-aminoethyl) aminopropyltrimethoxysilane and γ- (2-aminoethyl). ) Aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, etc., are effective for film formation. In terms of contribution, it is desirable to introduce a silanol group between molecules constituting the polyurethane resin, and a compound containing two or more active hydrogen groups is preferable.

（式中、Ｒ４は水素原子、アルキル基、アリール基及びアラルキル基からなる群より選ばれる一価の有機残基、Ｒ５及びＲ６は互いに独立に、アルコキシ基又は水酸基を表す。） In addition, the polyurethane resin further contains a functional group (b) represented by the following general formula [2] in the molecule, thereby further improving the stability of the treating agent and further forming a crosslinking reaction during baking and drying. Thus, the crosslinking density can be increased, and the corrosion resistance, post-processing corrosion resistance, solvent resistance, and alkali resistance can be improved.

(Wherein R4 represents a monovalent organic residue selected from the group consisting of a hydrogen atom, an alkyl group, an aryl group and an aralkyl group, and R5 and R6 each independently represents an alkoxy group or a hydroxyl group.)

  In order to contain the functional group (b), the active hydrogen group-containing compound (B) having one or more functional groups (b) in the molecule is used, and at least one functional group (a) is contained in the molecule. It can obtain by making it copolymerize at the time of reaction of the active hydrogen group containing compound (A) which has, and the said polyurethane prepolymer. Alternatively, an active hydrogen group-containing compound (B) having at least one functional group (b) in the molecule and an active hydrogen group-containing compound having at least one functional group (a) in the molecule ( A), the compound (C) having at least two active hydrogen groups per molecule, and the compound (D) having at least two isocyanate groups per molecule may be reacted at the same time.

  Examples of the active hydrogen group-containing compound (B) having at least one functional group (b) in the molecule include γ- (2-aminoethyl) aminopropyldimethoxysilane and γ- (2-aminoethyl). Examples include aminopropyldiethoxysilane, γ-aminopropyldimethoxysilane, γ-aminopropyldiethoxysilane, γ-mercaptopropyldimethoxysilane, γ-mercaptopropyldiethoxysilane, etc. In this respect, it is desirable to introduce a silanol group between molecules constituting the polyurethane resin, and a compound containing two or more active hydrogen groups is preferable.

The total amount of one or two functional groups (a) and (b) contained in the molecule of the polyurethane resin gives excellent cross-linking reactivity and performance to the polyurethane resin. On the other hand, 0.1 mass% or more and 5 mass% or less are preferable in conversion of silicon.
That is, the total amount of silicon mass Sa derived from the functional group (a) and the mass Sb of silicon derived from the functional group (b) is in the range represented by the following mathematical formula with respect to the total mass S of the nonvolatile solid content. It is preferable to do so.
0.1% by mass ≦ ((Sa + Sb) / S) × 100 ≦ 5% by mass
If the value of this formula is less than 0.1% by mass, it will not contribute properly to the crosslinking reaction, and the effect will be low. A more preferable range is 0.5 mass% or more and 3 mass% or less.

Examples of the compound (C) having at least two active hydrogen groups per molecule include compounds having an amino group, a hydroxyl group, and a mercapto group as compounds having an active hydrogen group. Considering the speed and mechanical properties after coating, a compound having a hydroxyl group is preferable because of its high reaction speed.
Further, the number of functional groups of the compound having an active hydrogen group is preferably 2 to 6 and particularly preferably 2 to 4 in terms of maintaining good mechanical properties of the coating film.
The molecular weight of the compound having an active hydrogen group is preferably from 200 to 10,000, and particularly preferably from 300 to 5,000, from the viewpoint of the content of urethane bonds given to the final coating film performance and the workability in production.

  Examples of the compound (C) having an active hydrogen group include polycarbonate polyol, polyester polyol, polyether polyol, polyester amide polyol, acrylic polyol, polyurethane polyol, and mixtures thereof.

  Examples of the compound (D) having at least two isocyanate groups per molecule include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,2- Butylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,6-diisocyanate methyl caproate, etc. Aliphatic isocyanates such as 1,3-cyclopentane diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, 3- Methyl-3,5,5-trimethylcyclohexyl isocyanate, 4,4'-methylenebis (cyclohexyl isocyanate), methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 1,2-bis (isocyanate) Naphthomethyl) cyclohexane, 1,4-bis (isocyanatomethyl) cyclohexane, 1,3-bis (isocyanatomethyl) cyclohexane and the like, for example, m-xylene diisocyanate, m-phenylene diisocyanate, p- Phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2, Aromatic diisocyanates such as 6-tolylene diisocyanate, 4,4′-toluidine diisocyanate, dianisidine diisocyanate, 4,4′-diphenyl ether diisocyanate, for example, ω, ω′-diisocyanate-1,3-dimethylbenzene, ω, aromatic aliphatic diisocyanates such as ω′-diisocyanate-1,4-dimethylbenzene, ω, ω′-diisocyanate-1,4-diethylbenzene, for example, triphenylmethane-4,4′-4 ″ -triisocyanate, Triisocyanates such as 1,3,5-triisocyanatebenzene and 2,4,6-triisocyanatetoluene, for example, 4,4′-diphenyldimethylmethane-2,2 ′, 5,5′-tetraisocyanate, etc. Polyisocyanate containing tetraisocyanate Nate monomer, polyisocyanate derivatives derived from dimer, trimer, burette, allophanate, carbodiimide derived from the above polyisocyanate monomer and the above polyisocyanate monomer, for example, ethylene glycol, propylene glycol, Adducts of low molecular weight polyols having a molecular weight of less than 200 such as butylene glycol to the above polyisocyanate monomers, and the above polyisocyanate single amounts such as polyester polyols, polyether polyols, polycarbonate polyols, polyester amide polyols, acrylic polyols, polyurethane polyols, etc. Examples include adducts to the body.

  In the present invention, the polyurethane resin can be polymerized by reacting a predetermined amount of the chain extender with the polyurethane resin, and the corrosion resistance, post-processing corrosion resistance, top coating adhesion, solvent resistance, and alkali resistance can be further enhanced.

  As said chain extension agent, a well-known polyamine compound etc. are used, for example. Examples of such polyamine compounds include ethylenediamine, 1,2-propanediamine, 1,6-hexamethylenediamine, piperazine, 2,5-dimethylpiperazine, isophoronediamine, 4,4′-dicyclohexyldiamine, 3,3. Diamines such as' -dimethyl-4,4'-dicyclohexylmethanediamine, 1,4-cyclohexanecyclohexanediamine, polyamines such as diethylenetriamine, dipropylenetriamine, triethylenetetramine, tetraethylenepentamine, hydroxyethylhydrazine, hydroxyethyl Examples thereof include compounds having an amino group and a hydroxyl group such as diethylenetriamine, 2-[(2-aminoethyl) amino] ethanol, and 3-aminopropanediol, hydrazines, and acid hydrazides. These polyamine compounds are used alone or in a mixture of two or more.

An active hydrogen group-containing compound (A) having at least one functional group (a) in the molecule and an active hydrogen group-containing compound having one or more functional groups (b) in the molecule (these chain extenders) A predetermined amount is mixed with the polyurethane prepolymer together with B).
At that time, it is desirable to control the composition ratio of the total amount of urea groups and urethane groups in the urethane resin in the total amount of the resin components to 0.1 mass% or more and 10 mass% or less in terms of nitrogen.
That is, the total amount of the mass Ta of nitrogen forming a urea bond (—NH—CO—NH—) and the mass Tb of nitrogen forming a urethane bond (—NH—CO—O—) is determined as the non-volatile solid content of the polyurethane resin. The mass T is in a range represented by the following mathematical formula.
0.1% by mass ≦ (Ta + Tb) / T) × 100 ≦ 10% by mass

  The chain extender is desirably mixed in a ratio of 0.1% by mass or more and 10% by mass or less in terms of nitrogen atom with respect to the total amount of the polyurethane prepolymer. If the mixing amount is less than 0.1% by mass, the target urea amount cannot be obtained, and solvent resistance, adhesion to the base metal material or top coating, corrosion resistance, and scratch resistance may decrease. If the mixing amount exceeds%, the film becomes too hard and the workability is lowered.

Further, by containing a cyclic compound, that is, a compound having an aliphatic ring or an aromatic ring in the polyurethane resin, the strength and solvent resistance of the film can be increased. Such a cyclic compound has both the case where it is couple | bonded as a substituent with the principal chain of a urethane resin, and the case where it couple | bonds as a side chain.
Examples of the compound having an aliphatic ring include a cyclohexanol group-containing compound, a cyclopentanol group-containing compound, an isophorone group-containing compound, a dicyclohexyl group-containing compound, and the like. Examples of the compound having an aromatic ring include a bisphenol group-containing compound, a cresol group-containing compound, and a diphenyl group-containing compound.
As for the content of the compound having an aliphatic ring or aromatic ring, the mass% of the total amount of the compound relative to the total solid content of the polyurethane resin is preferably 0.1% by mass or more and 30% by mass or less. If it is less than 0.1% by mass, the effect is poor, and if it exceeds 30% by mass, the film-forming property of the film is lowered, and the workability and the adhesion of the film itself may be lowered.

In addition, by containing a monomer having a branched structure in the polyol molecule constituting the polyurethane resin, the crosslinking reactivity at the time of film formation is further increased, the crosslinking density is increased, and the corrosion resistance, solvent resistance, and alkali resistance are increased. Can be improved.
Examples of the monomer having a branched structure include trimethylolpropane, pentaerythritol, castor oil, and the like. The amount to be blended is preferably 0.1% by mass to 30% by mass with respect to the total solid content of the polyurethane resin. If it is less than 0.1% by mass, the effect is poor, and if it exceeds 30% by mass, the hardness of the film becomes too high, and the workability and the adhesion of the film itself may deteriorate.

Further, in order to disperse the polyurethane resin in water, a hydrophilic group can be introduced into the polyurethane prepolymer. In order to introduce a hydrophilic group, for example, at least one active hydrogen group in the molecule and a hydrophilic group such as a carboxyl group, a sulfonic acid group, a sulfonate group, an epoxy group, or a polyoxyethylene group. What is necessary is just to copolymerize a containing compound (E) at the time of the said polyurethane prepolymer manufacture at least 1 or more types.
By selecting a carboxyl group as the hydrophilic group, it exhibits particularly excellent water dispersibility and stability of the emulsion in the treatment agent. Furthermore, it is preferable that content of a carboxyl group is 1000-3000 in an acid equivalent. If it is less than 1000, the stability of the emulsion is not sufficient, and the stability of the treating agent may be lowered. If it exceeds 3000, the alkali resistance and the solvent resistance may be lowered.

  Examples of the hydrophilic group-containing compound (E) include 2,2-dimethylolpropionic acid, 2,2-dimethylolbutyric acid, 2,2-dimethylolvaleric acid, dioxymaleic acid, and 2,6-dioxybenzoic acid. Carboxyl group-containing compounds such as 3,4-diaminobenzoic acid or derivatives thereof, or polyester polyols obtained by copolymerizing these, maleic anhydride, phthalic anhydride, succinic anhydride, trimellitic anhydride, pyrone anhydride A carboxyl group-containing compound obtained by reacting a compound having an anhydrous group such as merit acid and a compound having an active hydrogen group, or a derivative thereof, or a polyester polyol obtained by copolymerizing these, or at least 3 repeating units of ethylene oxide Containing at least 1% by mass, and at least one active hydrogen group in the polymer Polyethylene having a molecular weight of 300 to 10,000 which contain - nonionic group-containing compounds such as polyalkylene copolymer, or copolymerized with a polyether ester polyols obtained are mentioned these. In the copolymerization, these hydrophilic group-containing compounds are used alone or in combination of two or more.

In the polyurethane resin, a neutralizing agent is used in order to dissolve or disperse well in water.
Examples of neutralizing agents that can be used include tertiary amines such as ammonia, trimethylamine, triethylamine, triethanolamine, triisopropanolamine, and dimethylethanolamine, alkali metals such as sodium hydroxide, potassium hydroxide, and calcium hydroxide, Examples include basic substances such as hydroxides of alkaline earth metals. From the viewpoint of film-forming properties and surface treatment agent stability, alkylamines such as trimethylamine and triethylamine, or triethanolamine and dimethylethanolamine It is preferable to use at least one selected from alkanolamines.

  Further, the neutralizing agent preferably has a boiling point of 150 ° C. or lower. If the boiling point exceeds 150 ° C., a large amount of the neutralizing agent remains in the film after baking and drying, which may reduce the film-forming property of the film, and may decrease the corrosion resistance, alkali resistance, and solvent resistance. These neutralizing agents may be used alone or in a mixture of two or more. As a method for adding the neutralizing agent, it may be added directly to the polyurethane prepolymer, or may be added to water when it is dissolved or dispersed in water. The addition amount of the neutralizing agent is 0.1 to 2.0 equivalents, more preferably 0.3 to 1.3 equivalents with respect to a hydrophilic group such as a carboxyl group.

  In order to further improve the water solubility or dispersibility of the polyurethane prepolymer containing a hydrophilic group such as a carboxyl group, a surfactant may be used. Examples of such surfactants include nonionic surfactants such as polyoxyethylene nonylphenyl ether and polyoxyethylene-oxypropylene block copolymers, or anions such as sodium lauryl sulfate and sodium dodecylbenzenesulfonate. A surfactant is used. However, in view of performance such as corrosion resistance, alkali resistance, solvent resistance, etc., a soap-free type containing no surfactant is preferred.

  Self-emulsification without using a surfactant by selecting an alkanolamine having a carboxyl group in the polyurethane resin, an acid equivalent of 1000 to 3000, and a boiling point of 150 ° C. or less as a neutralizing agent at the time of water dispersion Water dispersion is possible, and the film-forming property of the film after baking and drying is most improved. That is, various performances such as corrosion resistance, alkali resistance, and solvent resistance can be most improved.

  Moreover, when synthesizing the polyurethane prepolymer, an organic solvent can be used. When an organic solvent is used, those having a relatively high solubility in water are preferable, and specific examples of such an organic solvent include acetone, ethyl methyl ketone, acetonitrile, N-methylpyrrolidone, and the like.

Further, a curing catalyst may be added in order to promote the reaction derived from the functional group (a) or (b) of the polyurethane resin of the present invention. In the polyurethane resin according to the present invention, a strongly basic tertiary amine specifically acts as a catalyst for forming a siloxane bond without deteriorating water resistance and solvent resistance when the polyurethane resin is coated. This makes it possible to efficiently introduce a crosslinked structure.
This strongly basic tertiary amine is characterized by a pKa of 11 or greater, in particular 1,8-diazabicyclo [5.4.0] undecene-7 (DBU) or 1,6-diazabicyclo [3. 4.0] Nonene-5 is preferably used. The strongly basic tertiary amine as the curing catalyst may be added during the synthesis of the polyurethane prepolymer, after the synthesis of the polyurethane prepolymer, or after the polyurethane prepolymer is dispersed or dissolved in water.

  In addition, a film-forming aid may be added to the polyurethane emulsion according to the present invention as necessary for the purpose of improving the film-forming property. Specific examples of such film-forming aids include, for example, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, hexanol, octanol, 2,2,4-trimethyl-1,3-pentanediol. Alcohols such as monoisobutyrate, cellosolve, ethyl cellosolve, butyl cellosolve, diethylene glycol monoethyl ether, ethylene glycol dimethyl ether, diethylene glycol monobutyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, dipropylene glycol monoisobutyl ether, tripropylene glycol Ethers such as monoethyl ether and tripropylene glycol monoisobutyl ether, butyl cellosolve acetate DOO, diethylene glycol monobutyl ether acetate, dipropylene glycol monobutyl ether acetate, glycol ether esters, such as tripropylene glycol mono isobutyl ether acetate, and the like. These film-forming aids are also used alone or in a mixture of two or more as required.

Moreover, in the surface treating agent in this invention, it is also possible to mix other resin other than a polyurethane resin. In this case, the total mass S of silicon derived from the functional group (a), the mass Sb of silicon derived from the functional group (b), and the mass of silicon Sc derived from silicon oxide is the total mass S of nonvolatile solids. On the other hand, it is a range represented by the following formula,
1.6% by mass ≦ ((Sa + Sb + Sc) / S) × 100 ≦ 25% by mass
In addition, as described above, the total amount of nitrogen that forms urea bonds and nitrogen that forms urethane bonds satisfies the condition of 0.1% by mass or more and 10% by mass or less with respect to the total amount of resin components in the solid content of the film. If so, an appropriate amount can be blended.

  Here, the above-mentioned “total amount of resin component” means the total amount of the polyurethane resin when the film contains only the polyurethane resin, and the total amount of the polyurethane resin and the other resin when other resins other than the polyurethane resin are included. To do. Moreover, as said other resin, an epoxy resin, an acrylic resin, polyolefin resin, polyester resin, polyether resin, etc. are illustrated. A polyolefin resin is preferable as the composite resin. Thus, when a polyurethane resin and a polyolefin resin are included in the film, a polyolefin resin having excellent corrosion resistance barrier properties and flexibility is added to the polyurethane resin having strong properties as a film and excellent adhesion. By including, in addition to the strength and adhesion of the film, it has the combined effect of further improving the corrosion resistance and workability of the film. The content of the polyolefin resin is preferably 5% by mass or more and 50% by mass or less. If it is less than 5% by mass, the above composite effect is poor, and if it exceeds 50% by mass, the characteristics of the polyurethane resin may not be sufficiently exhibited.

  Next, silicon oxide will be described. Examples of silicon oxide include silicon dioxide. Silicon oxide is not particularly limited as long as it is a compound that stably disperses in water and does not cause sedimentation. Among them, when colloidal silica is used, the effect of improving solvent resistance and corrosion resistance is remarkably exhibited. For example, commercially available colloidal silica particles such as “Snowtex O”, “Snowtex OS”, “Snowtex OXS”, “Snowtex N”, “Snowtex NS”, “Snowtex NXS” (all manufactured by Nissan Chemical Industries, Ltd.), Fibrous colloidal silica such as “Snowtex UP” and “Snowtex PS” (manufactured by Nissan Chemical Industries, Ltd.) can be used depending on the pH of the surface treatment agent.

  The silicon oxide content is preferably 1.5% by mass or more and 20% by mass or less in terms of silicon based on the solid content of the film. If it is less than 1.5% by mass, the effect is poor, and if it exceeds 20% by mass, the effect is saturated and uneconomical, and the workability and corrosion resistance may decrease. In the case of the surface-treated metal material, the total amount of silicon oxide, silicon derived from the functional group (a) and the functional group (b) is 1.6% by mass to 25% by mass with respect to the total solid content of the film. A preferable silicon content in the film is obtained.

Moreover, in the surface treating agent in this invention, additives, such as a crosslinking agent and a rust preventive agent other than a polyurethane resin, can be mixed.
Any crosslinking agent can be used as long as it is water-soluble or water-dispersible. Among them, the organic titanate compound that forms a crosslinked structure with an active hydrogen group such as a carboxyl group or a hydroxyl group is mainly mixed. The cross-linking reaction derived from the functional group (a), the functional group (b), and silicon oxide can be efficiently performed at a lower baking temperature. In addition, it is possible to crosslink hydrophilic groups contained in polyurethane resin molecules with other hydrophilic groups, dramatically improving the corrosion resistance, post-processing corrosion resistance, alkali resistance, and solvent resistance of the coating. To do.

  Examples of the organic titanate compound include olgatyx TC-300 (dihydrokisbis (ammonium lactate) titanium; manufactured by Matsumoto Pharmaceutical Co., Ltd.), TC-400 (diisopropoxytitanium bis (triethanolaminate); manufactured by Matsumoto Pharmaceutical Co., Ltd. And the like.

  Further, as the crosslinking agent, a carbodiimide group-containing compound or an oxazoline group-containing compound is further mixed with the surface treatment agent, thereby further reducing the crosslinking reaction derived from the functional group (a), the functional group (b), and silicon oxide. It can be carried out efficiently at the baking temperature, and it is further possible to crosslink the hydrophilic group contained in the molecule of the polyurethane resin with other hydrophilic groups.

  Examples of the carbodiimide group-containing compound include aromatic carbodiimide compounds and aliphatic carbodiimide compounds, and mainly form a crosslinked structure with active hydrogen groups such as carboxyl groups and hydroxyl groups. Examples thereof include Carbodilite V-02, V-02-L2, E-01, E-02, E-03A, and E-04 (manufactured by Nisshinbo Co., Ltd.).

  Examples of the oxazoline group-containing compound include Epocros K-2010E, K-2020E, K-2030E, WS-500, and WS-700 (manufactured by Nippon Shokubai Co., Ltd.). The oxazoline group-containing compound mainly reacts with a carboxyl group to form a crosslinked structure.

  The preferred addition amount of these crosslinking agents depends on the acid equivalent value of the resin, but from the balance of physical properties such as film curability, elongation, and hardness, it is based on the main resin (in the case of the present invention, polyurethane resin). 5 mass% or more and 50 mass% or less are preferable at solid content ratio of the crosslinking agent whole quantity.

The surface treatment agent of the present invention described above is applied to the surface of a metal material and dried to form a film. The metal material to be used is not particularly limited. For example, Al killed steel plate, ultra-low carbon steel plate to which Ti, Nb and the like are added, and high strength steel plate to which reinforcing elements such as P, Si and Mn are added, and Various materials such as materials obtained by plating them and Cr-containing steel typified by stainless steel can be applied.
Further, the present invention can be applied to metal materials other than Fe, such as other metal Al and Al alloy materials, metal Ti and Ti alloy materials, and Mg alloy materials.
Some of these are less necessary as a rust-proof coating, but can also be applied as a scratch-proof or design coating. Among them, the case of applying to a Zn-based plated steel sheet is particularly preferable.

  The coating layer of the steel material is not particularly limited, but in particular, Zn plating or Zn—Ni, Zn—Fe, Zn—Mg, Zn—Al, Zn—Cr, Zn—Ti, Zn—Mn, Zn—Al—Mg, Those plated with Zn-based alloys such as Zn—Al—Si and Zn—Al—Mg—Si exhibit the most excellent characteristics and can be replaced with chromate films. In addition, Al or an alloy composed of at least one of Al and Si, Zn, and Mg, for example, Al-based plating such as Al-Si alloy, Al-Zn alloy, Al-Si-Mg alloy, or Sn and Zn alloy It can also be applied to plating.

  In addition to the plate shape, the metal material should be applied to metal materials of various shapes such as tubular materials such as steel pipes, sheet pile materials such as steel sheet piles and H-shaped steel, and wire materials such as steel bars and wire rods. Is possible.

  The thickness of the film formed using the surface treating agent of the present invention is preferably 0.1 μm or more and 5 μm or less for normal use. If it is less than 0.1 μm, the contribution to the corrosion resistance is small. If it is 5 μm or more, the effect is saturated and uneconomical.

  In the formed film, for example, the total amount of silicon derived from the functional group (a), silicon derived from the functional group (b), and silicon derived from silicon oxide is 1.6 mass relative to the total mass of the nonvolatile solid content. % To 25% by mass, but the various components constituting the film as described above are mass spectrometry, X-ray fluorescence analysis, nuclear magnetic resonance spectroscopy, infrared spectroscopy, X-ray photoelectron spectroscopy, Quantitative analysis is possible by using or combining known methods such as an X-ray microanalyzer. Here, in the present invention, the “other functional group” means, for example, a dehydration condensation bond by reacting with a silanol group such as a hydroxyl group, an amino group, an isocyanate group, an imide group, an oxazoline group, an epoxy group, or an alkoxyl group. And a general term for functional groups that form crosslinks.

The surface treatment agent can be applied to the metal material by a known method such as spray coating, roll coating, bar coating, dipping or electrostatic coating.
Baking and drying may be performed by a known method using a hot air drying furnace, an induction heating furnace, a near-infrared furnace, a direct-fired furnace, or the like, or a combination thereof. Depending on the type of resin used, it can be cured by energy rays such as ultraviolet rays and electron beams. The heating temperature is preferably 100 ° C to 250 ° C in terms of the ultimate plate temperature. Below 100 ° C., drying for a long time is necessary for sufficient crosslinking, which is not practical. If it exceeds 250 ° C., thermal decomposition of the organic resin occurs, which adversely affects the corrosion resistance. Industrially, 130 to 200 ° C is more preferable.
Moreover, the cooling after heat drying is possible by well-known methods, such as water cooling and air cooling, or those combinations.

  In the present invention, before forming the film, by adding a chemical conversion treatment film such as a phosphate treatment film to the metal material, or by a two-stage treatment of the same film, further multi-layer treatment As a result, it is possible to further improve the corrosion resistance and impart functions as needed. In addition, as post-plating treatment, before chemical conversion treatment, zero spangle treatment that is uniform appearance after hot dipping, annealing treatment that is modification treatment of plating layer, temper rolling for adjustment of surface condition and material, etc. However, in the present invention, these are not particularly limited and can be applied.

  EXAMPLES Hereinafter, although the manufacture example and Example which concern on this invention are shown and this invention is demonstrated further in detail, this invention is not limited only to the following Example.

<Production Example 1: Polyurethane resin A>
In a four-necked flask equipped with a stirrer, Dimroth cooler, nitrogen inlet tube, silica gel drying tube, thermometer, 145.37 g of 1,3-bis (isocyanatomethyl) cyclohexane, 20.08 g of dimethylolpropionic acid, neopentyl glycol 15.62 g, polycarbonate diol 74.93 g having a molecular weight of 1000, and 64.00 g of acetonitrile as a solvent were added, and the mixture was heated to 75 ° C. and stirred for 3 hours under a nitrogen atmosphere. In this case, the content of urea group and urethane group is 3.3% by mass in terms of nitrogen atom.
After confirming that the predetermined amine equivalent had been reached, the temperature of the reaction solution was lowered to 40 ° C., and then 15.16 g of triethylamine (boiling point 89 ° C.) was added, and 1,8-diazabicyclo [5.4. 0] 0.25 g of undecene-7 (DBU) was added to obtain an acetonitrile solution of a polyurethane prepolymer.
Using a homodisper in an aqueous solution in which 32.82 g of this polyurethane prepolymer was dissolved in 25.38 g of KBM-603 (manufactured by Shin-Etsu Chemical Co., Ltd.) and 11.43 g of hydrazine monohydrate was dissolved in 700.00 g of water. By dispersing, chain extension reaction, emulsification, and further by distilling off the acetonitrile used in the synthesis of the polyurethane prepolymer under reduced pressure of 50 ° C. and 150 mmHg, the solvent substantially does not contain a solid content concentration of 30% by mass, A polyurethane resin emulsion A having a viscosity of 30 mPa · s (25 ° C.) and an acid equivalent of 2000 was obtained.

<Production Example 2: Polyurethane resin B>
327.82 g of the polyurethane prepolymer produced in the same manner as in Production Example 1, 11.78 g of KBM-602 (manufactured by Shin-Etsu Chemical Co., Ltd.), 12.69 g of KBM-603 (manufactured by Shin-Etsu Chemical Co., Ltd.), hydrazine Chain extension reaction, emulsified by dispersing with homodisper in an aqueous solution in which 11.43 g of monohydrate is dissolved in 700.00 g of water, and further used at the time of synthesizing polyurethane prepolymer under reduced pressure of 50 ° C. and 150 mmHg By distilling off the acetonitrile, a polyurethane resin emulsion B having a solid content concentration of 30% by mass, a viscosity of 30 mPa · s (25 ° C.), and an acid equivalent of 2000 was obtained.

<Production Example 3: Polyurethane resin C>
In a four-necked flask similar to Production Example 1, 1,3-bis (isocyanatomethyl) cyclohexane 143.57 g, dimethylolpropionic acid 21.56 g, neopentyl glycol 3.35 g, bisphenol A PO ₂ mol adduct 55 34.18 g of polycarbonate diol having a molecular weight of 1000 and 64.00 g of acetonitrile as a solvent were added, and the mixture was heated to 75 ° C. and stirred for 3 hours under a nitrogen atmosphere. In this case, the concentration of urea group and urethane group is 4.5% by mass in terms of nitrogen atom.
After confirming that a predetermined amine equivalent had been reached, the temperature of the reaction solution was lowered to 40 ° C., 16.25 g of triethylamine (boiling point 89 ° C.) was added, and 1,8-diazabicyclo [5.4. 0] 0.25 g of undecene-7 (DBU) was added to obtain an acetonitrile solution of a polyurethane prepolymer.
33.77 g of this polyurethane prepolymer, 10.67 g of KBM-602 (manufactured by Shin-Etsu Chemical Co., Ltd.), 11.50 g of KBM-603 (manufactured by Shin-Etsu Chemical Co., Ltd.), 10.34 g of hydrazine monohydrate By dispersing with a homodisper in an aqueous solution dissolved in 700.00 g of water to form a chain extension reaction and emulsification, and then distilling off the acetonitrile used during the synthesis of the polyurethane prepolymer under reduced pressure of 50 ° C. and 150 mmHg. A polyurethane resin emulsion C having a solid content concentration of 30% by mass, a viscosity of 30 mPa · s (25 ° C.), and an acid equivalent of 1900 was obtained.

<Production Example 4: Polyurethane resin D>
In the same four-necked flask as in Production Example 1, 139.35 g of 1,3-bis (isocyanatomethyl) cyclohexane, 21.39 g of dimethylolpropionic acid, 8.32 g of neopentyl glycol, 7.14 g of trimethylolpropane, and a molecular weight of 1000 79.81 g of the polycarbonate diol and 64.00 g of acetonitrile as a solvent were added, heated to 75 ° C. under a nitrogen atmosphere, and stirred for 3 hours. In this case, the concentration of urea group and urethane group is 2.3% by mass in terms of nitrogen atom.
After confirming that the predetermined amine equivalent was reached, the temperature of this reaction solution was lowered to 40 ° C., then 16.12 g of triethylamine (boiling point 89 ° C.) was added, and 1,8-diazabicyclo [5.4. 0] 0.25 g of undecene-7 (DBU) was added to obtain an acetonitrile solution of a polyurethane prepolymer.
314.58 g of this polyurethane prepolymer, KBN-602 (Shin-Etsu Chemical Co., Ltd.) 10.39 g, KBM-603 (Shin-Etsu Chemical Co., Ltd.) 11.20 g, hydrazine monohydrate 10.08 g By dispersing with a homodisper in an aqueous solution dissolved in 700.00 g of water to form a chain extension reaction and emulsification, and then distilling off the acetonitrile used during the synthesis of the polyurethane prepolymer under reduced pressure of 50 ° C. and 150 mmHg. A polyurethane resin emulsion D having a solid content concentration of 30% by mass, a viscosity of 30 mPa · s (25 ° C.), and an acid equivalent of 1900 was obtained.

<Production Example 5: Polyurethane resin E>
In a four-necked flask similar to Production Example 1, 145.37 g of 1,3-bis (isocyanatomethyl) cyclohexane, 20.08 g of dimethylolpropionic acid, 15.62 g of neopentyl glycol, 74.93 g of polycarbonate diol having a molecular weight of 1000, As a solvent, 64.00 g of acetonitrile was added, and the mixture was heated to 75 ° C. and stirred for 3 hours under a nitrogen atmosphere. In this case, the concentration of urea group and urethane group is 6.8% by mass in terms of nitrogen atom. After confirming that the predetermined amine equivalent was reached, the reaction solution was cooled to 40 ° C., 13.37 g of dimethylethanolamine (boiling point 135 ° C.) was added, and 1,8-diazabicyclo [5. 4.0] undecene-7 (DBU) 0.25 g was added to obtain an acetonitrile solution of a polyurethane prepolymer. 327.98 g of this polyurethane prepolymer, KBM-602 (Shin-Etsu Chemical Co., Ltd.) 11.85 g, KBM-603 (Shin-Etsu Chemical Co., Ltd.) 12.77 g, hydrazine monohydrate 11.49 g By dispersing with a homodisper in an aqueous solution dissolved in 700.00 g of water to form a chain extension reaction and emulsification, and then distilling off the acetonitrile used during the synthesis of the polyurethane prepolymer under reduced pressure of 50 ° C. and 150 mmHg. A polyurethane resin emulsion E having a solid content concentration of 30% by mass, a viscosity of 30 mPa · s (25 ° C.), and an acid equivalent of 2000 was obtained.

<Production Example 6: Polyurethane resin F>
In a four-necked flask equipped with a stirrer, a Dimroth cooler, a nitrogen inlet tube, a silica gel drying tube, and a thermometer, 155.87 g of 4,4′-methylenebis (cyclohexyl isocyanate), 27.36 g of dimethylolpropionic acid, neopentyl glycol 1.93 g, 4.39 g of 1,6-hexanediol, 111.38 g of a polyester polyol having a molecular weight of 1000 consisting of adipic acid, neopentyl glycol, and 1,6-hexanediol, and 130 g of N-methylpyrrolidone as a solvent, The mixture was stirred at 80 ° C. for 4 hours under a nitrogen atmosphere. In this case, the concentration of urea group and urethane group is 15% by mass in terms of nitrogen atom.
After confirming that the predetermined amine equivalent was reached, the reaction solution was cooled to 40 ° C., and 20.00 g of triethylamine (boiling point 89 ° C.) was added to carry out a neutralization reaction. A pyrrolidone solution was obtained.
The polyurethane prepolymer (436.41 g) was dispersed in an aqueous solution in which 7.77 g of hydrazine monohydrate was dissolved in 543.81 g of water by using a homodisper to form a chain extension reaction, which was emulsified. A polyurethane resin emulsion F having a mass%, a viscosity of 100 mPa · s (25 ° C.), and an acid equivalent of 1500 was obtained.

<Production Example 7: Polyurethane resin G>
In a four-necked flask equipped with a stirrer, Dimroth cooler, nitrogen inlet tube, silica gel drying tube, thermometer, 145.37 g of 1,3-bis (isocyanatomethyl) cyclohexane, 20.08 g of dimethylolpropionic acid, neopentyl glycol 15.62 g, polycarbonate diol 74.93 g having a molecular weight of 1000, and 64.00 g of acetonitrile as a solvent were added, and the mixture was heated to 75 ° C. and stirred for 3 hours under a nitrogen atmosphere. In this case, the content of urea group and urethane group is 3.3% by mass in terms of nitrogen atom.
After confirming that the predetermined amine equivalent had been reached, the temperature of the reaction solution was lowered to 40 ° C., and then 15.16 g of triethylamine (boiling point 89 ° C.) was added, and 1,8-diazabicyclo [5.4. 0] 0.25 g of undecene-7 (DBU) was added to obtain an acetonitrile solution of a polyurethane prepolymer.
This polyurethane prepolymer (327.82 g) was homogenized in an aqueous solution in which KBM-602 (Shin-Etsu Chemical Co., Ltd.) 23.55 g, 11.78 g, and hydrazine monohydrate 11.43 g were dissolved in 700.00 g of water. Dispersing with a disper, chain extension reaction, emulsified, and further distilled off acetonitrile used in the synthesis of polyurethane prepolymer under reduced pressure at 50 ° C. and 150 mmHg, so that the solid content concentration is substantially free of solvent. A polyurethane resin emulsion G having 30% by mass, a viscosity of 30 mPa · s (25 ° C.), and an acid equivalent of 2000 was obtained.

  A polyurethane resin Aa having an acid equivalent adjusted to 800, a polyurethane resin Ab having an acid equivalent adjusted to 3500, and a neutralizing agent triethylamine (boiling point 89) with exactly the same raw materials and manufacturing method as polyurethane resin A of Production Example 1 ° C.) to 2-amino-2-methyl-1-propanol (boiling point 165 ° C.) was changed to polyurethane resin Ac, and ammonia was changed to polyurethane resin Ad.

<Production and evaluation of metal surface treatment materials>
Using the various urethane resins described above, various additives were mixed to obtain a metal surface treating agent shown in Table 1.

The contents of the polyolefin resin, colloidal silica, and crosslinking agent in the treating agent shown in Table 1 are as follows.
Polyolefin resin: HYTEC S-3121 (manufactured by Toho Chemical Industry Co., Ltd.)
Colloidal silica F: Snowtex N (manufactured by Nissan Chemical Industries)
Colloidal silica G: Snowtex NS (manufactured by Nissan Chemical Industries)
Crosslinking agent H: Carbodiimide compound; Carbodilite E-03A (Nisshinbo Co., Ltd.)
Cross-linking agent J: oxazoline compound; Epocross WS-700 (manufactured by Nippon Shokubai Co., Ltd.)
Cross-linking agent K: organic titanate compound; Olgatics TC-400 (manufactured by Matsumoto Pharmaceutical Co., Ltd.)

The following metal materials were used as the metal plate.
L: electrogalvanized steel sheet; plate thickness 1.0 mm, plating adhesion 20 g / m ²
M: electrogalvanized-Ni alloy plated steel sheet; plate thickness 0.8 mm, plating adhesion 20 g / m ²
N: hot-dip galvanized steel sheet; plate thickness 0.9 mm, plating adhesion 50 g / m ²
P: hot dip zinc-iron alloy plated steel sheet; plate thickness 0.8 mm, plating adhesion 45 g / m ²
Q: Molten zinc-11% Al-3% Mg-0.2% Si; plate thickness 0.8 mm, plating adhesion 60 g / m ²
R: hot-dip zinc-55% Al; plate thickness 0.8 mm, plating adhesion 75 g / m ²
S: stainless steel plate; plate thickness 0.5 mm, ferritic stainless steel plate,
Steel component: C; 0.008 mass%, Si; 0.07 mass%, Mn; 0.15 mass%, P; 0.011 mass%, S; 0.009 mass%, Al; 0.067 mass% Cr: 17.3% by mass, Mo: 1.51% by mass, N: 0.0051% by mass, Ti: 0.22% by mass, balance Fe and inevitable impurities

  The metal plate was alkali degreased immediately before use, then washed with water and dried. Further, the surface treatment agent shown in Table 1 was applied with a bar coater, baked and dried in a hot air drying furnace, washed with water, and dried to obtain a test material. The oven temperature during baking and drying was 300 ° C., and the ultimate temperature was 150 ° C. as the ultimate plate temperature. Details of the specimens thus obtained are shown in Table 2.

The following evaluation was performed on the prepared specimens. The results are shown in Table 3.
(1) Film adhesion A 1 mm grid was placed on the film surface of the test material with a cutter knife, and further extruded 7 mm with an Erichsen tester so that the film surface was convex, and then a tape peeling test was performed. About the method of putting a grid, the extrusion method of Erichsen, and the method of tape peeling, it implemented according to the method of JIS-K5400.88.2 and JIS-K5400.88.5. Evaluation after tape peeling was performed by 10-point full scale evaluation by the example figure of evaluation of JIS-K5400.88.5.

(2) Adhesion of topcoat paint Melamine alkyd paint (Super Rack 100, manufactured by Nippon Paint Co., Ltd.) was applied to the surface of the test material with a bar coater to a dry film thickness of 20 μm, and baked at 120 ° C. for 25 minutes. Produced. Leave it for a whole day and night, then immerse it in boiling water for 30 minutes, take it out for a day, put 100 grid cuts with 1 mm spacing, and apply cellophane (registered trademark) tape (manufactured by Nichiban Co.) to the part. The film state after the observation was observed and evaluated according to the following criteria. About the method of putting a grid and peeling the tape, it implemented according to the method of JIS-K5400.88.2 and JIS-K5400.88.5.
5: Number of peels 0
4: Number of peels 5 or less
3: Number of peeled 10 or less
2: Number of peels 50 or less
1: Number of peels 51 or more

(3) Solvent resistance A rubbing test with ethyl methyl ketone was performed on the coating surface of the test material. The gauze was fixed to the tip of a 15 mmφ silicon rubber cylinder, 5 mL of ethyl methyl ketone was contained, and then slid 10 times under the condition of a load of 4.9N. The edge and the back surface of the test piece were tape-sealed, and a salt spray test (JIS-Z-2371) was performed. The occurrence of white rust after 72 hours was observed and evaluated according to the following criteria.
5: No white rust
4: White rust generation less than 1%
3: White rust generated 1% or more and less than 5%
2: White rust generation 5% or more and less than 20%
1: White rust generation 20% or more

(4) Alkali resistance After immersing the test material in a 2% by weight aqueous solution (pH 12.5) of an alkaline degreasing agent (Surf Cleaner 53, Nippon Paint Co., Ltd.) at 55 ° C. for 5 minutes, the edge and back surface of the test plate Was subjected to a salt spray test (JIS-Z-2371). The occurrence of white rust after 72 hours was observed and evaluated according to the following criteria.
5: No white rust
4: White rust generation less than 1%
3: White rust generated 1% or more and less than 5%
2: White rust generation 5% or more and less than 20%
1: White rust generation 20% or more

(5) Corrosion resistance (i) Flat part:
About the flat plate test piece which sealed the end surface and the back surface, the salt spray test (SST) prescribed | regulated to JIS-Z2371 was implemented, and it evaluated by the incidence rate of the white rust 240 hours afterward. Corrosion resistance evaluation criteria are shown below.
5: No white rust
4: White rust generation less than 1%
3: White rust generated 1% or more and less than 5%
2: White rust generation 5% or more and less than 20%
1: White rust generation 20% or more (ii) After processing:
For flat plate test pieces with end and back surfaces sealed, 7 mm Erichsen processing was applied to the center, and then the salt spray test (SST) specified in JIS-Z2371 was performed. The rate was evaluated. Corrosion resistance evaluation criteria are shown below.
5: No white rust
4: White rust generation less than 1%
3: White rust generated 1% or more and less than 5%
2: White rust generation 5% or more and less than 20%
1: White rust generation 20% or more

  No. 1 which is a comparative example of the present invention. 44 was found to be inferior in corrosion resistance, alkali resistance and solvent resistance because it does not contain functional groups (a) and (b). No. 44 was found to be inferior in corrosion resistance after processing because the amount of urea groups and urethane groups in the polyurethane resin was too large. No. 45 contained only the functional group (b), but was found to be inferior in alkali resistance and solvent resistance. No. No. 46 was found to be inferior in corrosion resistance because it contains no silicon oxide. No. In No. 41, the treatment agent gelled at room temperature for 7 days. Other No. No abnormal appearance was observed after 14 days at room temperature.

No. 3 to 13 , 15 to 17 , 19 to 21 , 23 to 25 , 27 to 29 , 31 to 33 , 35 to 37 , by using the film configuration of the examples of the present invention, extremely high corrosion resistance and post-processing corrosion resistance, and It was found that good topcoat paint adhesion, alkali resistance, and solvent resistance can be obtained.

  As mentioned above, although preferred embodiment of this invention was described, it cannot be overemphasized that this invention is not limited to this example. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

  The present invention is a surface-treated metal material and metal that do not contain hexavalent chromium having high environmental impact, have extremely high corrosion resistance and post-processing corrosion resistance, and have good topcoat paint adhesion, alkali resistance, and solvent resistance. Applicable to surface treatment agents.

Claims (13)

It contains a polyurethane resin containing a functional group (a) represented by the following general formula [1] and a functional group (b) represented by the following general formula [2] in the molecule, and silicon oxide. Metal surface treatment agent.

(In the formula, R1, R2 and R3 each independently represents an alkoxy group or a hydroxyl group.)

(Wherein R4 represents a monovalent organic residue selected from the group consisting of a hydrogen atom, an alkyl group, an aryl group and an aralkyl group, and R5 and R6 each independently represents an alkoxy group or a hydroxyl group.) The total amount of silicon derived from the functional group (a), silicon derived from the functional group (b), and silicon derived from the silicon oxide is in the range represented by the following formula with respect to the total mass of the nonvolatile solid content. The metal surface treatment agent according to claim 1, wherein
1.6% by mass ≦ ((Sa + Sb + Sc) / S) × 100 ≦ 25% by mass
Where S: total mass of non-volatile solids
Sa: Mass of silicon derived from the functional group (a)
Sb: Mass of silicon derived from the functional group (b)
Sc: Mass of silicon derived from silicon oxide The polyurethane resin contains a urea bond in the molecule, and the total amount of nitrogen derived from the urea bond and nitrogen derived from the urethane bond is represented by the following formula with respect to the mass of the nonvolatile solid content of the polyurethane resin. The metal surface treatment agent according to claim 1 or 2 , wherein the metal surface treatment agent is within a range.
0.1% by mass ≦ (Ta + Tb) / T) × 100 ≦ 10% by mass
Here, T: mass of non-volatile solid content of polyurethane resin
Ta: Mass of nitrogen forming a urea bond (—NH—CO—NH—)
Tb: mass of nitrogen forming a urethane bond (—NH—CO—O—) The metal surface treating agent according to any one of claims 1 to 3 , comprising an organic titanate compound as a crosslinking agent for the polyurethane resin. The metal surface treating agent according to any one of claims 1 to 4 , wherein the polyurethane resin is water-dispersible or water-soluble and contains a carboxyl group in the molecule. The metal surface treatment agent according to claim 5 , wherein an acid equivalent of the polyurethane resin is 1000 to 3000. The metal surface treatment agent according to claim 5 or 6 , wherein the boiling point of the neutralizing agent when the polyurethane resin is dispersed in water is 150 ° C or lower. The metal surface treatment agent according to any one of claims 5 to 7 , wherein the neutralizing agent at the time of water dispersion of the polyurethane resin is at least one selected from alkylamine and alkanolamine. The metal surface treatment agent according to any one of claims 5 to 8 , further comprising a carbodiimide compound or an oxazoline group-containing compound as a crosslinking agent for the polyurethane resin. Furthermore, 5 to 50 mass% of polyolefin resin is contained with respect to the total amount of non-volatile solid content, The metal surface treating agent in any one of Claim 1 to 9 characterized by the above-mentioned. On the surface of the metal material is coated with a metal surface treatment agent according to any one of claims 1 to 10, a surface treatment method for a metal material and forming a film by drying. A surface-treated metal material comprising a film formed by using the surface treatment method according to claim 11 . The surface-treated metal material according to claim 12, wherein the metal material is a zinc-based plated steel plate or an aluminum-based plated steel plate.