JP5364390B2 - Non-chromium aqueous rust preventive surface treatment agent for metal parts with zinc surface - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To impart satisfactory rust inhibitive performance by applying a chromium-free rust inhibitive surface treating agent on the surface of a metal member having a zinc surface to form a thin film. <P>SOLUTION: A chromium-free rust inhibitive surface rearing agent of an aqueous solution composed of an aqueous colloidal silica stabilized at pH of an acid side, a water soluble titanium chelate compound coordinated with an organic acid such as lactic acid, malic acid and tartaric acid, a silane coupling agent which is water soluble and exhibits no alkaline property and a mixed solvent of alcohol and water, is prepared and applied on the surface of the metal member having the zinc surface to form a thin silica film containing a titanium component and having 0.4 to 3 &mu;m thickness. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

The present invention forms a siliceous thin film on the surface of a metal member having a zinc surface such as a steel bolt, nut, steel plate, wire rod and zinc alloy die-cast member subjected to electrogalvanization or hot dip galvanization. The present invention relates to a non-chromium aqueous rust preventive surface treatment agent that can prevent the occurrence of white rust and red rust for a long time, and a metal member having a zinc surface that is rust-prevented with this non-chromium rust preventive surface treatment agent.

In the European ELV Directive (Waste Car Directive) and the RoHS Directive (Restriction Directive on the Use of Specific Chemical Substances Included in Electrical and Electronic Equipment), hexavalent chromium is designated as a specific chemical substance because of its toxicity and carcinogenicity. Chromate treatment using hexavalent chromium on the zinc surface is now regulated. For this reason, the surface treatment of the zinc surface using trivalent chromium is prevailing now. However, it is difficult to prevent a part of trivalent chromium from changing to hexavalent chromium due to an equilibrium reaction, and a hexavalent chromium is always included in a film that has been rust-prevented using a treatment liquid containing trivalent chromium. In some cases, hexavalent chromium containing chromium and having a concentration close to the current regulation value is detected in the film.

For this reason, there are many experts who think that the surface treatment agent using the trivalent chromium component which is now widely used is also shifted to the non-chromium surface treatment agent excluding the chromium component. The use of non-chromium rust preventive surface treatment agent that does not contain chromium components has the advantage of significantly reducing wastewater treatment costs. When newly installing galvanizing equipment, it accounts for a large portion of the capital investment. There is an advantage that the cost of waste water treatment equipment can be reduced.

The inventors of the present invention have an alcohol solution of an alkoxysilane oligomer having a specific weight average molecular weight, which can prevent the occurrence of white rust for a long time when a thin siliceous film is formed by coating on the surface of a metal member having a zinc surface. Invented a non-chrome anti-rust surface treatment agent consisting of
Patent Document 1). This rust preventive surface treatment agent forms a thin film of about 2μm and exhibits rust prevention performance comparable to chromate treatment and self-healing when the film is damaged, and also has excellent rust prevention performance to prevent white rust. ing.

Since this non-chromium rust preventive surface treatment agent does not contain a chromium component, when newly installing a galvanizing facility, the waste water treatment facility can be simplified, the equipment investment can be reduced, and the waste water treatment cost is also reduced. However, because the surface treatment agent uses an alcohol solvent, it is subject to restrictions in handling by the Fire Service Act as a flammable hazard in Japan. For this reason, when installing a large-scale surface treatment facility, notification to the fire department and permission are required. In addition, since galvanizing contractors are accustomed to using aqueous chromate treatment agents, there is a problem that hesitates to use unfamiliar surface treatment agents based on alcohol solvents.

The present inventors performed a non-chromium chemical conversion treatment on the surface of a metal member having a zinc surface,
The surface is coated with a non-chromium rust preventive surface treatment agent using a single solvent of alcohol or a mixed solvent of water and alcohol, and a thin siliceous film is formed to improve the rust prevention performance against white rust generation of metal parts. Invented a surface treatment method capable of stably imparting good rust prevention performance, and applied for a patent (Patent Document 2).

The inventors of the present invention invented a surface treatment agent containing an ultrafine powder of titanium oxide dispersed in an alcohol solution of an alkoxysilane oligomer for the purpose of improving rust prevention performance, and a metal having a zinc surface. Used for product surface treatment. However, after a long period of time after the formation of the siliceous film, the siliceous film on the zinc surface cracks and peels off, and it appears that white rust is generated by the powder of the peeled film, and the rust prevention performance deteriorates. Admitted. In addition, when the titanium oxide ultrafine powder contained in the siliceous film becomes agglomerated, there is a problem that the film looks whitish.

In order to overcome these problems, the present inventors have shown that the adhesion of the siliceous film to the zinc surface is good, and that the anti-chromium coating for zinc surface exhibits good rust prevention performance even when the formed film is thin. A rust surface treatment agent was invented and a patent application was filed (Patent Document 3). This non-chromium rust preventive surface treatment agent is composed of an alcohol solution of alkoxysilane oligomer molecules containing a titanium component by combining a titanium chelate compound with an alkoxysilane oligomer. Even if the siliceous film formed using this non-chromium antirust surface treatment agent has a thickness of less than 1 μm, it can impart good antirust performance to a metal member having a zinc surface. Furthermore, by forming a thin interdiffusion layer of about 30 nm at the boundary between the galvanized surface and the siliceous film, the adhesion between the galvanized surface and the siliceous film is significantly improved, and the film can be prevented from peeling off. Became.

As an aqueous non-chromium anti-rust surface treatment agent, it is coordinated to titanium or zirconium alkoxide compounds to inorganic-organic composites composed of water-dispersible silica such as colloidal silica and water-soluble or water-dispersible organic polymer resins. An aqueous metal surface treatment composition combining a chelate compound to which a compound is bonded has been developed 30 years ago (Patent Document 4).

Further, a treatment solution containing colloidal silica and lithium silicate so that Si / Li (molar ratio) is 36 to 66 is directly applied to a metal plate or a plated metal plate without performing chromate treatment, and then 200 ° C. The surface treatment metal plate which dried and formed the surface treatment film | membrane below is developed (patent document 5). In addition, a surface-treated steel sheet including a carboxyl group-containing resin and an inorganic silicate, and further having a coating of an inorganic silicate containing a titanium compound using a surface treatment agent containing a titanium compound has been developed (Patent Document 6).

In addition, an aqueous non-chromium chemical conversion treatment solution containing a water-soluble titanium compound, colloidal silica, and a cobalt compound that can be used for rust prevention on the zinc surface, and titanium, cobalt compound, and silica are bonded to the zinc surface treated with this chemical conversion treatment solution. An antirust treatment liquid containing a titanium component, colloidal silica, and a cobalt compound that forms a film has been developed (Patent Document 7). In addition, an aqueous non-chromium metal surface treatment agent containing a silane coupling agent or a hydrolysis polymer thereof, an aqueous silica sol, and either a zirconium compound or a titanium compound has been developed (Patent Document 8).
9).

JP 2005-264170 A JP 2006-225761 A WO2007 / 119812A1 JP 54-74236 A Japanese Patent No. 2953658 JP 2000-282254 A JP 2000-328271 A JP 2001-240979 A JP 2001-316845 A

Surface treatment agent for alcohol solution of alkoxysilane oligomer previously invented by the present inventors,
In particular, a non-chromium antirust surface treatment agent mainly composed of an alcohol solution of an alkoxysilane oligomer in which a titanium compound is bonded to an oligomer molecule is a surface treatment agent that forms a thin siliceous film of about 1 μm. This siliceous film can impart excellent rust prevention performance to metal parts when applied to metal parts having a zinc surface, exhibits good self-healing properties when the film is damaged, and has good adhesion to the zinc surface. good.

However, after changing the surface treatment agent of galvanized products from chromate treatment agents to trivalent chrome treatment agents, galvanizing contractors who have a short operation period are currently receiving non-chromium protection products when their trivalent chrome treatment products are accepted by users. I don't think about moving to surface treatment with rust surface treatment agents.
Furthermore, this non-chromium rust preventive surface treatment agent is restricted by the Fire Service Act when a mass production treatment facility is introduced into a factory because the solvent is a flammable alcohol. In addition, galvanizing contractors who are accustomed to aqueous chromate treatment agents tend to hesitate to introduce surface treatment agents using alcohol solvents.

The present invention aims to eliminate these problems, and can be used for rust prevention treatment of metal members having a zinc surface, and can provide rust prevention performance comparable to conventional chromate treatment using hexavalent chromium. In addition to providing a treating agent, an object of the present invention is to provide a metal member having a zinc surface having a practical level of rust prevention performance, which has been subjected to a rust prevention treatment with this non-chromium aqueous rust prevention surface treatment agent.

The inventors of the present invention have been working on the development of a non-chromium aqueous rust preventive surface treatment using water for forming a siliceous film as a solvent. However, when the galvanized member is surface-treated with a water-based non-chromium rust preventive surface treatment agent, the occurrence of red rust can be suppressed for a long time, but there is a problem that it is practically insufficient because the occurrence of white rust is early.

Subsequently, the inventors have found that when a titanium component is introduced into the siliceous film, the rust prevention performance for a metal member having a zinc surface is improved. Furthermore, based on the knowledge that it is possible to obtain better rust prevention performance by using an aqueous solvent mixed with an alcohol component, it is stabilized at an acidic pH with the property that it does not gel when mixed with alcohol. A surface treatment agent using aqueous colloidal silica as a silica component has been reached.

In addition, by blending a weakly acidic or neutral water-soluble titanium chelate compound into an aqueous surface treating agent solution containing water-based colloidal silica as a main raw material, the zinc surface has good antirust performance against the occurrence of white rust. The present inventors have found that a non-chromium aqueous rust preventive surface treatment agent that can be applied to a metal member is obtained.

The non-chromium aqueous rust preventive surface treatment agent for metal members having a zinc surface according to the present invention (hereinafter referred to as “surface treatment agent of the present invention”) is composed of an aqueous colloidal silica stabilized at an acidic pH, An aqueous solution containing a titanium chelate compound of an organic acid, a water-soluble silane coupling agent that is soluble in water and does not exhibit alkalinity, and a mixed solvent of alcohol and water, and is applied to the surface of a metal member having a zinc surface. It is used as a treating agent for forming a siliceous film.

In the surface treating agent of the present invention, the water-soluble organic acid is preferably lactic acid, malic acid or tartaric acid.

The surface treating agent of the present invention is an aqueous solution containing a mixed solvent of an alcohol component and water, and the concentration of the alcohol component in the mixed solvent is 15 in combination with the alcohol component generated when the silane coupling agent is hydrolyzed. It is preferably ˜40% by weight.

Surface treatment agent of the present invention, by converting the titanium component of the titanium chelate compounds in water-soluble organic acid to TiO _2, silica silica (SiO ₂₎ and the total amount of TiO ₂ in the in the film formed on the zinc surface,
Preferably it contains ₂ to 6% by weight of TiO2.

The surface treatment agent of the present invention preferably contains 0.3 to 4.0% by weight of an organic resin component in the aqueous solution.

In the surface treating agent of the present invention, the organic resin component is preferably polyacrylic acid, a water-soluble epoxy resin, a water-soluble polyvinyl butyral resin, or a water-soluble phenol resin.
The surface treatment agent of the present invention contains a high boiling alcohol having a boiling point of 100 ° C. or higher in the aqueous solution, and the proportion of the high boiling alcohol in the alcohol component is preferably 10 to 50% by weight.

The metal member having a zinc surface according to the present invention is characterized in that the surface treatment agent is applied and coated with a siliceous film having a thickness of 0.4 to 3 μm containing a titanium component.

The surface treatment agent of the present invention is a non-chromium antirust surface treatment agent. If this surface treatment agent is applied to a metal member having a zinc surface to form a thin siliceous film, white rust is generated in a salt spray test. Can be imparted with rust prevention performance that prevents the rust from being lost for 100 hours or more.

The surface treatment agent of the present invention includes an aqueous colloidal silica stabilized at an acidic pH, an alcohol solvent, a silane coupling agent that does not exhibit alkalinity when dissolved in water, and a titanium chelate of a water-soluble organic acid. The compound is mixed with an aqueous solution containing an alcohol solvent. Aqueous solutions in which various compounds are blended with aqueous colloidal silica often have problems with stability. If the balance is slightly lost, gelation will occur and sufficient pot life (
In many cases, the pot life cannot be secured. As the surface treating agent of the present invention, a composition having a practically sufficient pot life (for example, 3 months or more) has been selected as a result of various combinations of constituent components.

In the present invention, the siliceous film means that the ratio of the SiO ₂ component in the film is 60% by weight or more, preferably 65% by weight or more. If the proportion of the SiO ₂ component in the film is less than 60% by weight, the desired antirust effect cannot be imparted with a thin film. Moreover, by mix | blending a silane coupling agent, it is set as the stable aqueous solution containing the alcohol solvent by improving the affinity between the silica particle of water-system colloidal silica, and the titanium chelate compound of the organic acid mentioned later. The titanium component is introduced in order to improve the rust prevention performance to which the siliceous film can be applied. In the siliceous film, an organic component derived from the silane coupling agent and a titanium compound other than TiO ₂ may be contained as a residual component, but it does not affect the rust prevention performance.
The type and amount of these residual components vary depending on the baking temperature of the film.

The preferable amount of aqueous colloidal silica in the aqueous solution is preferably 65% by weight or more in terms of the silica component in the film. By using water-based colloidal silica as the main raw material for the surface treatment agent, a non-chromium aqueous rust-proof surface treatment agent can be prepared at a practical price. The other silica component contained in the surface treating agent of the present invention is derived from the silane coupling agent.

The stable pH range of the aqueous colloidal silica is on both the acidic side and the alkaline side, and the aqueous colloidal silica is commercially available in a state stabilized in any pH range. Aqueous colloidal silica gels immediately or outside of this stable pH range. Commercially available aqueous colloidal silica that is stabilized at an acidic pH has the property that it can be mixed with an alcohol solvent without gelling the solution.

By mixing alcohol with such aqueous colloidal silica and preparing an aqueous solution of a mixed solvent of water and alcohol, a composition of a stable surface treatment agent can be prepared, and the rust prevention performance of the surface-treated product can be improved. The present inventors have found that this is possible. Examples of commercially available aqueous colloidal silica that can be used as the surface treating agent of the present invention include Snowtex-O manufactured by Nissan Chemical Industries, Ltd. and Cataloid-SN manufactured by Catalyst Chemical Industries, Ltd.

When other components such as a titanium compound and a resin are added to the surface treatment agent, it is necessary to add a silane coupling agent. The formulation of the silane coupling agent serves to stabilize the aqueous solution of the surface treatment agent. If the amount of the silane coupling agent is small, the stability of the aqueous solution is impaired. The compounding amount of the silane coupling agent in the surface treatment agent of the present invention is S in the siliceous film.
It is preferably 10 to 30% by weight in terms of iO ₂ component amount. If the compounding amount of the silane coupling agent is small, the blended effect cannot be obtained, and if it is too much, the cost of the surface treatment agent increases for the obtained effect. A more preferable blending ratio of the silane coupling agent is 15 to 32% by weight in terms of the amount of SiO ₂ component in the film. It is not preferable to add a large amount of a relatively expensive silane coupling agent because it increases the cost of the surface treatment.

The silane coupling agent has a function of improving the affinity between the aqueous colloidal silica and the water-soluble titanium chelate compound or resin to help form a stable aqueous solution. As the silane coupling agent that can be used for this purpose, a water-soluble silane coupling agent that can be dissolved in water and exhibits neutrality when dissolved in water is used.

The water-soluble silane coupling agent that can be used in the surface treatment agent of the present invention includes a silane coupling agent having an epoxy functional group, and as a silane coupling agent having an epoxy functional group,
Examples include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, and 2- (3,4-epoxycyclohexylethyl) trimethoxysilane.

Since a commercially available titanium chelate compound of a water-soluble organic acid is relatively expensive, the treatment cost for the surface treatment increases for the effect obtained when blended in a large amount. For this reason, the amount of the water-soluble titanium chelate compound to be blended in the solution of the surface treatment agent of the present invention is converted to the TiO ₂ component in the siliceous film, and the total amount of silica (SiO ₂ ) and TiO _{2 in} the siliceous film The content is preferably 1 to 7% by weight. If it is less than 1% by weight, the effect of introducing the TiO ₂ component into the siliceous film is small, and if it is more than 7% by weight, the cost of the surface treatment increases for the obtained effect. TiO in siliceous film
The more preferable content of the _two components is 2 to 6% by weight.

Commercially available water-soluble titanium chelate compounds include those chelated with amine compounds and those chelated with organic acids. TC-400 (titanium diisopropoxytriethanolamate) manufactured by Matsumoto Fine Chemical Co., chelated with commercially available triethanolamine exhibits alkalinity when dissolved in water. When this titanium chelate compound solution is mixed with aqueous colloidal silica stabilized on the acidic side, it gels. Further, a solution in which TC-400 exhibiting alkalinity is mixed with colloidal silica stabilized on the alkali side,
When mixed with alcohol solvent, it does not gel and become a clear solution.

A titanium chelate compound in which an organic acid is coordinated (hereinafter referred to as “a titanium chelate compound of an organic acid”) is a titanium compound that can form an aqueous solution without being gelled when mixed with water. Organic acids are said to have a chelating function. However, organic acids that can be dissolved in a considerable amount in water to form a stable titanium chelate solution are limited. For example, an attempt to chelate with citric acid or succinic acid does not gel to form a transparent solution, but when lactic acid, malic acid or tartaric acid is used, an organic acid titanium chelate compound capable of forming an aqueous solution can be prepared.

Commercially available water-soluble titanium chelate compounds that can be preferably used in the surface treatment agent of the present invention include titanium lactate chelated with lactic acid and ammonium salt of titanium lactate (both are in a solution state). These are, for example, TC-310 (manufactured by Matsumoto Fine Chemical Co., Ltd.)
TC-300 (which is neutralized with ammonium and exhibits a neutral pH) can be obtained.

Although no commercial products are found, a water-soluble titanium chelate compound using malic acid or tartaric acid as a chelating agent can also be used. In order to prepare a water-soluble titanium chelate compound using an organic acid as a chelating agent, for example, it can be prepared by mixing tetraisopropoxy titanium in an isopropyl alcohol solution of an organic acid. Malic acid can be dissolved in isopropyl alcohol to a concentration of about 1 molar. On the other hand, tartaric acid is slightly less soluble in isopropyl alcohol.

The main component of the mixed solvent forming the surface treating agent of the present invention is water, but it contains an alcohol component as a subcomponent. Water is introduced from a solution of aqueous colloidal silica and a titanium chelate compound, but when using aqueous colloidal silica having a high silica concentration, water is appropriately blended.

The reason is not clear, but by using a surface treatment agent as a mixed solvent containing water and an alcohol component, the rust prevention performance that can be imparted by a film formed on the surface of a metal member having a zinc surface can be significantly improved. When the alcohol component is contained, foaming of the surface treatment agent is suppressed, and when the surface treatment agent is applied to a product, bubbles can be prevented from entering the coating film to make the siliceous film non-uniform. The alcohol component includes alcohol components such as ethanol and methanol generated by hydrolysis of the silane coupling agent in addition to the alcohol added as a solvent. The solution of the organic acid titanium chelate compound also contains isopropyl alcohol and the like.

The content of the alcohol component contained in the mixed solvent of the aqueous solution is 15 to 15 so that the siliceous film formed by the surface treatment agent of the present invention can impart good rust prevention performance to a metal member having a zinc surface.
It is preferably 40% by weight, more preferably 25 to 35% by weight. If the content of the alcohol component in the mixed solvent is less than 15% by weight, the rust prevention performance that can be imparted by the silica film is reduced,
Even if the blending amount is further increased beyond 40% by weight, the effect of improving the rust prevention performance is small. According to the Japanese Fire Service Law, in the case of a mixed solution having a flash point of less than 21 ° C., the specified quantity that can be handled is 400 liters, but if the flash point is 21 ° C. or more, the designated quantity that can be handled is 2000 liters. In the case of an ethanol aqueous solution, if the ethanol concentration is less than 60% by weight, the designated quantity according to the Fire Service Act is 2000 liters, and the installation of treatment equipment is easy. By using an aqueous surface treatment agent with a high flash point, the solvent is less evaporated and it is difficult to ignite so that it is easy to handle.

Examples of the alcohol component include low-boiling alcohols such as methanol, ethanol, n-propanol, and isopropanol, butanol, methyl cellosolve, ethyl cellosolve, propylene glycol monomethyl ether (PGME), butyl cellosolve, and ethylene glycol monotertiary butyl ether (ETB). High boiling alcohols such as diformaldehyde methoxyethanol can be used. It is preferable to blend a high-boiling alcohol such as PGME or ETB, since the wet coating immediately after coating is gradually dried and a siliceous coating with few defects such as cracks can be formed. The proportion of high-boiling alcohol having a boiling point of 100 ° C. or higher in the alcohol component contained in the aqueous solution of the surface treatment agent is preferably 15 to 55% by weight.

In the surface treatment agent of the present invention, an organic resin that is soluble in a mixed solvent of water and alcohol is preferably blended in a solution state. In the case of a powdery resin, it is dissolved in advance and blended in the form of a liquid resin solution. In addition to reducing the hardness of the siliceous film, the addition of organic resin to the surface treatment agent has the effect of reducing the friction coefficient of an excessively large siliceous film when a rust preventive film is formed on the surface of fastener parts such as bolts and nuts. is there.

In many cases, the compounding of the organic resin into the surface treatment agent of the present invention degrades the rust prevention performance, so that the compounding amount should not be too large. The blending ratio of the organic resin in the surface treatment agent of the present invention is from 0.3 to
It is preferably 4.0% by weight, more preferably 0.6 to 3.5% by weight. If the blending ratio is small, the effect obtained is small, and if it is too large, the rust preventive performance that the film can impart to the metal member is impaired. Examples of the organic resin that can be blended in the surface treatment agent of the present invention include a water-soluble phenol resin, a polyvinyl butyral resin, a polyacrylic acid resin, and a polyester resin.

When the object to be treated is a small object such as a bolt or nut, the surface treatment agent of the present invention is obtained by immersing a metal member having a zinc surface in a solution of the surface treatment agent and putting it in a basket attached to a centrifuge. It is preferable to employ a coating method in which the coating is carried out by dip-and-spin, which is shaken and the excess surface treatment agent attached to the surface is shaken off, dried at about 80 ° C. and then heated at 100 to 200 ° C.

At this time, the thickness of the siliceous film formed on the treated surface is more preferably 0.6 to 1.8 μm. When applying a surface treatment agent to a galvanized steel sheet, a method using a roll coater, a dip drain method in which the galvanized steel sheet is dipped in a surface treatment liquid, and a method of spray-coating the surface treatment agent can be adopted. When liquid sag occurs, it is preferable to apply means for removing excess surface treatment liquid with a roll or brush.

The metal member having a zinc surface of the present invention is characterized by being coated with a siliceous film having a thickness of 0.4 to 3 μm containing a titanium component, to which the surface treatment agent of the present invention described above is applied,
When put in a salt spray tester according to JIS Z 2371 and evaluate the rust prevention performance of the metal member, generation of white rust can be prevented over a long period of 100 to 200 hours. When the thickness of the siliceous film is less than 0.4 μm, practical rust prevention performance cannot be imparted, and even when the thickness exceeds 3 μm, the effect of further improving the rust prevention performance is small, and surface treatment per unit area is small. This is uneconomical because the required amount of surface treatment agent increases. A more preferable thickness of the siliceous film is 0.6.
˜1.8 μm.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated concretely, this invention is not limited to these Examples. The specifications of the chemicals used are as follows.

Colloidal silica A: (Snowtex-O), pH 2-4, manufactured by Nissan Chemical Industries, Ltd., containing 20 wt% silica component, and other components are water.
Colloidal silica B: (Cataloid-SN), pH 2-4, manufactured by JGC Catalysts & Chemicals Co., Ltd., containing 20 wt% silica component, and other components are water.
Colloidal silica C: (Snowtex-XS), pH 9-10, manufactured by Nissan Chemical Industries, Ltd., containing 20 wt% silica component, and other components are water.

Silane coupling agent A: (Z-6040), manufactured by Toray Dow Corning Co., Ltd., 3-glycidoxypropyltrimethoxysilane, Si containing 21.6 wt% in terms of SiO ₂ component.
Silane coupling agent B :) (Z-6043), manufactured by Toray Dow Corning Co., Ltd., 2- (3,4-
24.4wt epoxycyclohexylethyl) trimethoxysilane, and Si in the SiO ₂ component in terms
% Is included.
Silane coupling agent C: (Z-6011), manufactured by Toray Dow Corning Co., Ltd., aminopropyltriethoxysilane, and Si containing 21.6 wt% in terms of SiO ₂ component.

Titanium chelate compound solution A: (TC-300), titanium lactate ammonium salt solution, manufactured by Matsumoto Fine Chemical Co., Ltd., Ti is 11.3 wt% in terms of TiO ₂ component, water is 20 wt%, IP
Contains 38 wt% A.
Titanium chelate compound solution B: (TC-310), titanium lactate solution, manufactured by Matsumoto Fine Chemical Co., Ltd., containing 13.5 wt% of Ti in terms of TiO ₂ component, 16 wt% of water, and 40 wt% of IPA.
Titanium chelate compound solution C: (containing malic acid), a solution obtained by chelating 2 mol of isopropyl alcohol solution of malic acid to 1 mol of tetraisopropyl titanate, and containing 4.5 wt% of Ti in terms of TiO ₂ component.
Titanium chelate compound solution D: (with tartaric acid), 10 wt% isopropyl alcohol solution of tartaric acid in the same molar amount of tetrabutyl titanate (manufactured by Matsumoto Fine Chemical Co., Ltd., TA-25)
A solution containing 5.6 wt% of Ti in terms of TiO ₂ component.

Water-soluble epoxy resin solution: (Denacol EX-821), manufactured by Nagase ChemteX Corporation, contains 99 wt% or more of polyethylene glycol diglycidyl ether.
Polyacrylic acid aqueous solution: (AQUALIC HL), manufactured by Nippon Shokubai Co., Ltd., 45wt% of polyacrylic acid
% Aqueous solution.
Polyvinyl acetal resin solution: (ESREC KX-5), manufactured by Sekisui Chemical Co., Ltd., resin component
A solution containing 8 wt%, IPA 35 wt%, and water 57 wt%.
Water-soluble phenol resin solution: (Shonol BRL-120Z), Showa Polymer Co., Ltd., resin component
A solution containing water in addition to 71.6 wt%.

IPA: isopropyl alcohol ETB: ethylene glycol monotertiary butyl ether PGME: propylene glycol monomethyl ether

Tables 1 and 2 show the component compositions of the surface treatment agents of Examples 1 to 12 and Comparative Examples 1 to 9, the coating film thickness, salt spray test data, and the like, respectively. The total amount (parts by weight) of the alcohol is a value obtained by adding the alkoxy groups of the silane coupling agent and tetraalkoxytitanium as hydrolyzed to become alcohol. TiO ₂ / (TiO ₂ + SiO ₂ ) in the film is a ratio obtained by calculation by converting Ti in the siliceous film formed on the surface of the galvanized bolt into a TiO ₂ component. F20 Thin-Film A manufactured by Filmetrics Co., Ltd.
Measurement was performed using a narizer, and an average value was shown in Tables 1 and 2 together.

In Examples 1-12, as shown in Table 1, the film thickness of the siliceous film is 0.5 μm to 1.8 μm.
No cracks were observed on the film by microscopic observation, and white rust was the earliest occurrence of 144
After the time, red rust was observed at the earliest time after 396 hours.

From the results obtained in Examples 1 to 13, the surface treatment agent of the present invention consisting of a composition containing an aqueous colloidal silica, a silane coupling agent and an organic acid chelate titanium compound in an aqueous mixed solution containing an alcohol component. It can be seen that a good antirust performance can be imparted to a metal member having a zinc surface by thinly coating the metal member to form a siliceous film. Furthermore, an organic resin solution can be blended with the surface treatment agent, an organic resin component can be introduced into the siliceous film, and the hardness and friction coefficient of the siliceous film can be adjusted.

From the results shown in Comparative Examples 1 to 9, the range of the composition that can keep the composition of the surface treatment agent of the present invention in a stable solution state is limited, and in the composition outside the scope of the present invention, zinc It can be seen that the antirust performance that can be imparted to the metal member having the surface is inferior, or the composition becomes an unstable composition and gelation occurs, making it difficult to ensure the pot life.

50 parts by weight of colloidal silica A (Snowtex-O) was used as the aqueous colloidal silica. Colloidal silica A has a silica particle diameter of 10 to 20 nm, and has an acidic pH (2
It is stabilized in ~ 4).

As the silane coupling agent, 20 parts by weight of silane coupling agent A (Z-6040) was used. As a titanium chelate compound of an organic acid, a titanium chelate compound solution A (TC-
300) was used in an amount of 6 parts by weight. TC-300 is a solution containing 42% by weight of a titanium ammonium lactate salt which is neutral (pH about 7) and neutralized with ammonia, and contains IPA and water.
Furthermore, 10 parts by weight of isopropyl alcohol was used.

The aqueous surface treating agent of Example 1 contains 41.2 parts by weight of water and 20.4 parts by weight of alcohol in combination with water contained in the aqueous colloidal silica and the TC-300 solution. The proportion of the alcohol component is about 33.1% by weight.

Zincate bath (also called alkali bath) was plated with a thickness of about 7μm and dried without activation using a dilute nitric acid aqueous solution (referred to as "whitening") M8 x 45mm size steel Four half screw bolts were prepared. These four bolts were immersed in the surface treatment agent liquid of Example 1 to give vibration and wetted well with the surface treatment agent solution. Then, the bolts were taken out of the solution and put into a stainless steel mesh tea strainer. Then, the tea strainer containing the bolts was placed in a centrifuge, and the centrifuge was rotated for 2 seconds at a rotation radius of about 15 cm and a rotation speed of 700 RPM to shake off excess liquid adhering to the bolt surface ( Dip and spin method). The bolt coated with the surface treatment agent by this method was placed in a dryer, heated to 100 ° C., held for 15 minutes, and cooled.

Of the four bolts, three bolts were placed in a salt spray tester according to JIS Z 2371 to evaluate the rust prevention performance of the surface treatment agent. Rust prevention performance is evaluated by visual inspection every 24 hours to check the occurrence of rust on the bolt surface, and the time when white rust is observed in two of the three, and
The time when red rust occurred was recorded on two of the three, and the time was shown as antirust performance. The results are also shown in Table 1.

As in Example 1, except that 6 g of titanium chelate compound solution B (TC-310) was used as the titanium chelate compound of the organic acid, and 4 parts by weight of IPA and 6 parts by weight of ETB were blended as the alcohol component. did. TC-310 is a solution having a pH of about 1 containing 44% by weight of titanium lactate.

Since the aqueous surface treating agent of Example 2 contains 41.2 parts by weight of water and 20.5 parts by weight of alcohol contained in the aqueous colloidal silica and the TC-310 solution, the proportion of alcohol in the mixed solvent is about 33. .2% by weight. The antirust performance of this surface treatment agent was evaluated in the same manner as in Example 1. The results are shown in Table 1.

The same procedure as in Example 1 was conducted except that the surface treating agent of Example 1 was further mixed with 6 parts by weight of an aqueous polyacrylic acid solution (Aquaric HL). In the aqueous surface treating agent of Example 3, 44.5 parts by weight of water contained in the solution of colloidal silica A and TC-300 and 20.4% of alcohol were used.
The proportion of alcohol in the mixed solvent is about 31.4% by weight. The antirust performance of this surface treatment agent was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 1 except that the amount of the silane coupling agent A was reduced to 15 parts by weight, 10 parts by weight of the titanium chelate compound solution C (with malic acid) was added instead of TC-300, and half of the IPA was replaced with PGME. And so on. Since the aqueous surface treating agent of Example 4 contains 40 parts by weight of water and 24.6 parts by weight of the alcohol component contained in the aqueous colloidal silica, the proportion of alcohol in the mixed solvent is about 38.1% by weight. is there. The antirust performance of this surface treatment agent was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 1 was repeated except that the silane coupling agent A was replaced with silane coupling agent B (Z-6043). In the aqueous surface treating agent of Example 5, 41.2 parts by weight of water and 21 parts by weight of the alcohol component contained in the aqueous colloidal silica and titanium chelate compound solution and 21 parts by weight of the alcohol component were included, so the proportion of alcohol in the mixed solvent was about 33. 0.7% by weight. The antirust performance of this surface treatment agent was evaluated in the same manner as in Example 1. The results are shown in Table 1.

The procedure was the same as Example 1 except that colloidal silica A was replaced with colloidal silica B (Cataloid-SN). In the aqueous surface treating agent of Example 6, 41.2 parts by weight of water and 20.4 parts by weight of the alcohol component contained in the aqueous colloidal silica and titanium chelate compound solution are contained, so the proportion of alcohol in the mixed solvent is About 33.1% by weight. The antirust performance of this surface treatment agent was evaluated in the same manner as in Example 1. The results are shown in Table 1.

The amount of silane coupling agent A was reduced to 15 parts by weight, and the same procedure as in Example 1 was carried out except that 7 parts by weight of a polyvinyl acetal resin solution (ESREC KX-5) was blended as a resin component. In the surface treating agent of Example 7, 45.2 parts by weight of water and alcohol component contained in the aqueous colloidal silica A, the titanium chelate compound solution, and the polyvinyl acetal resin solution were added.
Since 0.8 weight part is contained, the ratio of the alcohol in a mixed solvent is about 31.5 weight%. The antirust performance of this surface treatment agent was evaluated in the same manner as in Example 1. The results are shown in Table 1.

The same procedure as in Example 1 was conducted except that the amount of the silane coupling agent A was reduced to 10 parts by weight and 4 parts by weight of a water-soluble phenol resin solution (Shonol BRL-120Z) was added as a resin component. Since the surface treatment agent of Example 8 contains 42.4 parts by weight of water and 16.3 parts by weight of an alcohol component contained in the aqueous colloidal silica A, the titanium chelate compound solution, and the water-soluble phenol resin solution, the mixed solvent The proportion of alcohol in it is about 27.8% by weight.
The antirust performance of this surface treatment agent was evaluated in the same manner as in Example 1. The results are shown in Table 1.

The amount of the titanium chelate compound solution (TC-300) was reduced to 3 parts by weight, and the same procedure as in Example 1 was performed except that 4 parts by weight of a water-soluble phenol resin solution (Shonol BRL-120Z) was added as a resin component. . In the surface treating agent of Example 9, aqueous colloidal silica A
In addition, 42.1 parts by weight of water and 19.3 parts by weight of an alcohol component contained in the titanium chelate compound solution and the water-soluble phenol resin solution are contained, so that the ratio of alcohol in the mixed solvent is about 31.
4% by weight. The antirust performance of this surface treatment agent was evaluated in the same manner as in Example 1. The results are shown in Table 1.

The same procedure as in Example 1 was carried out except that the amount of the silane coupling agent A was reduced to 10 parts by weight and 7 parts by weight of a polyvinyl acetal resin solution (S-REC KX-5) was added as a resin component. The surface treatment agent of Example 10 contains 45.2 parts by weight of water and 18.8 parts by weight of the alcohol component contained in the aqueous colloidal silica A, the titanium chelate compound solution, and the polyvinyl acetal resin solution. The proportion of alcohol in it is about 29.4% by weight. The antirust performance of this surface treatment agent was evaluated in the same manner as in Example 1. The results are shown in Table 1.

The procedure was the same as Example 1 except that 3 parts by weight of a water-soluble epoxy resin (Tenacol EX-821) was blended as the resin component. In the surface treating agent of Example 11, 41.2 parts by weight of water contained in the aqueous colloidal silica A and the titanium chelate compound solution and an alcohol component of 20.
Since 4 parts by weight is contained, the proportion of alcohol in the mixed solvent is about 33.1% by weight. The antirust performance of this surface treatment agent was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Instead of titanium chelate compound solution A (TC-300), 10 parts by weight of titanium chelate compound solution D containing tartaric acid is added, IPA is not blended, and 7 parts by weight of polyvinyl acetal resin solution (ESREC KX-5) is used as a resin component. The procedure was the same as Example 1 except for the addition. In the surface treating agent of this Example 12, 44 parts by weight of water and 19.2 parts by weight of alcohol components contained in the aqueous colloidal silica A and the polyvinyl acetal resin solution are contained, so the proportion of alcohol in the mixed solvent is About 30.4% by weight. The antirust performance of this surface treatment agent was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Instead of titanium chelate compound solution A (TC-300), 10 parts by weight of titanium chelate compound solution D containing tartaric acid was added, and a water-soluble phenol resin solution (Shonol B) was added as a resin component.
RL-120Z) was the same as Example 1 except that 4 parts by weight was added. In the composition of Example 13, the water contained in the aqueous colloidal silica A and the water-soluble phenol resin solution was changed into 41.
Since 1 part by weight and 26.8 parts by weight of the alcohol component are contained, the proportion of alcohol in the mixed solvent is about 39.5% by weight. The antirust performance of this surface treatment agent was evaluated in the same manner as in Example 1.
The results are shown in Table 1.
[Comparative Example 1]

The amount of silane coupling agent A in the composition of Example 1 was reduced to 10 parts by weight, and IPA
Was added in the same manner as Example 1 except that 15 parts by weight of water (ion-exchanged water) and 7 parts by weight of the polyvinyl acetal resin solution (S-REC KX-5) were added.

The surface treating agent of Comparative Example 1 contains water derived from aqueous colloidal silica, a titanium chelate compound solution and a polyvinyl acetal resin solution, and 60.2 parts by weight of water in total including added water, and the alcohol component is 8.8 wt. Therefore, the proportion of alcohol in the mixed solvent is 12.8% by weight.

Since the composition of Comparative Example 1 had a short pot life and a part of the solution gelled after a few days, it became unusable as a surface treatment agent, and thus the subsequent evaluation was omitted.
[Comparative Example 2]

Example 1 except that the titanium chelate compound solution (TC-300) blended in the composition of Example 1 was not blended, and 7 parts by weight of the polyvinyl acetal resin solution (S-REC KX-5) was blended.
And so on.

Since the surface treating agent of Comparative Example 2 contains 44 parts by weight of water derived from the aqueous colloidal silica and the polyvinyl acetal resin solution and 20.6 parts by weight of the alcohol component, the proportion of alcohol in the mixed solvent is 31.9. % By weight.

The antirust performance of this surface treatment agent was evaluated in the same manner as in Example 1. Microscopic observation did not show any cracks in the film, but since the titanium chelate compound was not blended in the composition, the rust prevention performance that could be imparted to the galvanized bolt was low.
[Comparative Example 3]

Without adding the silane coupling agent A compounded in the composition of Example 1, the compounding amount of the titanium chelate compound solution (TC-300) was increased to 9 parts by weight, and the polyvinyl acetal resin solution (ESREC KX-57) was 7 weights. The same procedure as in Example 1 was performed except that 20 parts by weight of ion exchange water was blended.

The surface treatment agent of Comparative Example 3 is composed of 65.8 parts by weight of water obtained by combining water derived from an aqueous colloidal silica, a titanium chelate compound solution, and a polyvinyl acetal resin solution and ion-exchanged water, and 5.9% by weight of an alcohol component. Therefore, the ratio of alcohol in the mixed solvent is 8.2% by weight.

Since the composition of Comparative Example 3 had a short pot life and a part of the solution gelled after a few days, it was not usable as a surface treatment agent, and thus the subsequent evaluation was omitted. This test result is
Since the blending ratio of alcohol is small and no silane coupling agent is blended, the stability of the composition solution is poor, and it is estimated that a part of the solution is gelled.
[Comparative Example 4]

The same procedure as in Example 1 was conducted except that colloidal silica C (Snowtex-XS) stabilized on the alkali side was blended in place of colloidal silica A blended in the composition of Example 1.

Since the surface treatment agent of Comparative Example 4 contains 41.2 parts by weight of water combined with water derived from the aqueous colloidal silica and the titanium chelate compound solution, and 20.4 parts by weight of the alcohol component,
The proportion of alcohol in the mixed solvent is 33.1% by weight.

Since the composition of Comparative Example 4 had a short pot life and a part of the solution gelled after a few days, it was not usable as a surface treatment agent, and thus the subsequent evaluation was omitted. This test result is
Since it is a composition in which colloidal silica C stabilized on the alkali side is blended as colloidal silica, the composition lacks stability, and it is estimated that a part of the solution is gelled.
[Comparative Example 5]

Instead of the silane coupling agent A blended in the composition of Example 1, 15 parts by weight of the silane coupling agent C having an amine group was used, and the alkali of the attached amine group was acetic acid (4.1 parts by weight) in the same molar amount. This was the same as Example 1 except that 7 parts by weight of a polyvinyl acetal resin solution (ESREC KX-5) was blended and the blending amount of IPA was increased to 15 parts by weight.

Since the surface treating agent of Comparative Example 5 contains 45.2 parts by weight of water combined with water derived from the aqueous colloidal silica and the titanium chelate compound solution, and 29.1 parts by weight of the alcohol component,
The proportion of alcohol in the mixed solvent is 39.2% by weight.

Although a small amount of gel remained in the surface treatment agent of Comparative Example 5 and was not a uniform solution, the rust prevention performance was evaluated in the same manner as in Example 1. Microscopic observation showed no cracks in the film. Although it is not bad in performance, the gel does not disappear even if it is well stirred, and it is not preferable as a surface treatment agent.
[Comparative Example 6]

In place of colloidal silica A blended in the composition of Example 1, colloidal silica C (Snowtex-XS) was used, and 1 of silane coupling agent C (Z-6011) having an amine group was obtained.
5 parts by weight is neutralized with the same amount of acetic acid (corresponding to 4.1 parts by weight) of the attached amine group alkali, and the titanium chelate compound solution is not blended. The blending amount of IPA is 15 parts by weight. The procedure was the same as in Example 1 except that the number was increased.

Since the surface treating agent of Comparative Example 6 contains 40 parts by weight of water derived from aqueous colloidal silica and 24.3 parts by weight of the alcohol component, the proportion of alcohol in the mixed solvent is 37.8% by weight.
It is.

The composition of Comparative Example 6 had a short pot life, and after several days, the solution gelled and became unusable as a surface treatment agent. Therefore, the subsequent evaluation was omitted. This test result is a composition in which colloidal silica C stabilized on the alkali side is blended as colloidal silica, and the solution lacks stability due to the use of a silane coupling agent having an amine group. Estimated.
[Comparative Example 7]

60 parts by weight of colloidal silica A blended in the composition of Example 1 is blended, 10 parts by weight of titanium chelate compound solution C (containing malic acid) is blended without using a silane coupling agent, and IPA
4 parts by weight of water-soluble phenol resin (Shonol BRL-120Z) was added.

Since the surface treating agent of Comparative Example 7 contains 49.1 parts by weight of water derived from aqueous colloidal silica and a water-soluble phenol resin and 8.5 parts by weight of an alcohol component, the proportion of alcohol in the mixed solvent is 14 .8% by weight.

In the composition of Comparative Example 7, a precipitate was generated in the solution, and the composition could not be used as a surface treatment agent. Therefore, the subsequent evaluation was omitted. From this test result, since no silane coupling agent is blended, it is presumed that the phenol resin component cannot be accommodated in the solution in the surface treatment agent, and the resin component is precipitated and precipitated.
[Comparative Example 8]

Increasing the amount of colloidal silica A blended in the composition of Example 1 to 60 parts by weight, blending 6 parts by weight of titanium chelate compound solution B (TC-310) without blending the silane coupling agent,
In addition to 5 parts by weight of IPA, 7 parts by weight of a polyvinyl acetal resin solution (ESREC KX-5) was blended.

In the surface treatment agent of Comparative Example 8, 52.9 parts by weight of water derived from an aqueous colloidal silica, a titanium chelate compound solution, and a polyvinyl acetal resin solution, and an alcohol component of 9.9
Since a part by weight is included, the ratio of the alcohol in the mixed solvent is 15.7% by weight.

In the composition of Comparative Example 8, a part of the solution gelled after 24 hours and became unusable as a surface treatment agent, and thus the subsequent evaluation was omitted. This test result is presumed that since the silane coupling agent was not blended, the polyvinyl acetal resin component could not be accommodated in the solution in the surface treatment agent, and the resin component was gelled.
[Comparative Example 9]

Increasing the amount of colloidal silica A blended in the composition of Example 1 to 60 parts by weight, blending 6 parts by weight of titanium chelate compound solution B (TC-300) without blending the silane coupling agent,
In addition to 5 parts by weight of IPA, 7 parts by weight of a polyvinyl acetal resin solution (ESREC KX-5) was blended.

In the surface treatment agent of Comparative Example 9, 53.2 parts by weight of water derived from aqueous colloidal silica, a titanium chelate compound solution, and a polyvinyl acetal resin solution, and an alcohol component of 9.7
Since a part by weight is contained, the proportion of the alcohol in the mixed solvent is 15.4% by weight.

In this Comparative Example 9 composition, a part of the solution gelled after several days and became unusable as a surface treatment agent, and thus the subsequent evaluation was omitted. This test result is presumed that since the silane coupling agent was not blended, the phenol resin component could not be accommodated in the solution in the surface treatment agent, and the resin component was precipitated and gelled.

The surface treatment agent of the present invention is an aqueous non-chromium antirust surface treatment agent. If the water-based surface treatment agent of the present invention containing more water than the alcohol component is used, the restrictions imposed by the Fire Service Act can be reduced as compared with the case of using a non-chromium antirust surface treatment agent using an alcohol solution. Therefore, even in a factory that mass-produces galvanized products that require the use of a large amount of treatment solution, the rust-proof surface treatment can be performed without any problem. Therefore, it is expected to be used as a new surface treatment agent in place of the surface treatment agent using a trivalent chromium component that is currently popular.

Claims (8)

An aqueous solution comprising an aqueous colloidal silica stabilized at an acidic pH, a titanium chelate compound of a water-soluble organic acid, a silane coupling agent that is soluble in water and does not exhibit alkalinity, and a mixed solvent of alcohol and water. A non-chromium aqueous rust preventive surface treatment agent for a metal member which is a solution and is used as a treatment agent which is applied to the surface of a metal member having a zinc surface to form a siliceous film. The non-chromium aqueous antirust surface treating agent for metal members according to claim 1, wherein the titanium chelate compound is a titanium chelate compound of an organic acid coordinated with an organic acid selected from lactic acid, malic acid, or tartaric acid. The non-chromium for a metal member according to claim 1 or 2, wherein the concentration of the alcohol component in the aqueous solution is 15 to 40% by weight in the mixed solvent of the alcohol component generated when the silane coupling agent is hydrolyzed. Aqueous anti-rust surface treatment agent. When the content of the titanium chelate compound of the organic acid contained in the aqueous solution is converted to TiO ₂ when the titanium component of the titanium chelate compound of the water-soluble organic acid is converted to TiO ₂ , the silica in the siliceous film formed on the zinc surface (SiO 2 ₂₎ and in the total amount of TiO _2, claim including TiO ₂ 1 to 7 wt% 1
4. The non-chromium aqueous rust preventive surface treatment agent for metal members according to any one of 3 above. The non-chromium aqueous rust preventive surface treatment agent for metal members according to any one of claims 1 to 4, further comprising 0.3 to 4.0% by weight of an organic resin component in the aqueous solution. The non-chromium aqueous rust preventive surface treatment agent for metal members according to claim 5, wherein the organic resin component is polyacrylic acid, water-soluble epoxy resin, water-soluble polyvinyl butyral resin, or water-soluble phenol resin. The metal member according to any one of claims 1 to 6, wherein the aqueous solution contains a high-boiling alcohol solvent having a boiling point of 100 ° C or higher, and the proportion of the high-boiling alcohol solvent in the alcohol solvent is 10 to 50% by weight. Non-chromium aqueous rust preventive surface treatment agent. A siliceous film having a thickness of 0.4 to 3 µm, which is coated with the non-chromium aqueous rust preventive surface treatment agent for metal members according to any one of claims 1 to 7 and contains a titanium component derived from a titanium chelate compound of an organic acid. A metal member having a zinc surface, characterized by being coated with: