JPH06145558A - Heat-resistant undercoating agent for metal - Google Patents

Abstract

PURPOSE:To provide the title agent which can give improved adhesion and long-term heat resistance by reacting a specified aminoalkylalkoxysilane hydrolyzate with a specified aqueous silicate solution. CONSTITUTION:The agent is obtained by reacting an aminoalkylalkoxysilane hydrolyzate of the formula wherein R<1> is a 1-4C bivalent hydrocarbon group; R<2> and R<3> are each a 1-4C monovalent hydrocarbon group; A is H or aminoalkyl; and m is 1 or 0 with an aqueous solution (of a Baume degree of 30-60 at 15 deg.C) of a silicate of an SiO2/M2O molar ratio of 0.5-4 wherein M is Li, Na or K in a weight ratio of 1/(20-10).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is applied to various metals such as iron, stainless steel, galvanized steel sheet, aluminum, copper, brass, etc., fluororesin type, polyimide type, polyamide imide type,
The present invention relates to a heat-resistant coating base adhesion-imparting agent for various metals capable of improving the adhesion of a so-called high temperature (260 ° C. or higher) baking type heat-resistant coating material such as ceramics and maintaining the heat resistance for a long period of time.

[0002]

2. Description of the Related Art When it is desired to coat various metals with a high temperature baking of 260 ° C. or higher, such as fluororesin type, polyimide type, polyamide imide type and ceramic type paints without impairing the adhesiveness (1) Chromate with chromic acid Method of performing treatment (2) Method of performing anchor effect treatment by sandblasting (3) Method of using titanium sulfate and sodium silicate described in JP-B-60-22068 (4) JP-B-56-33468 A method is known in which the described fluorides such as titanium and zirconium are used as a surface treatment agent.

However, the chromate treatment method with chromic acid has a difficulty in waste treatment due to the use of harmful substances, and the sandblast treatment has a difficulty in corrosion resistance after coating.
In the case of using the compounds (3) and (4), the treatment liquid conditions in a limited pH range are necessary, and it is difficult to easily obtain a stable heat-resistant coating base treatment system.

[0004]

Therefore, the inventor of the present invention
As a result of various studies on heat-resistant coating base treatment agents for heat-resistant coatings that are safe and non-toxic and can be easily used in building baths, a composition consisting of hydrolysis products of aminoalkylcoxysilane and various silicates The inventors have found that the drawbacks of the prior art can be overcome and have completed the present invention.

The object of the present invention is to provide various heat-resistant paints such as fluororesin-based, polyimide-based, polyamide-imide-based, ceramic-based, etc., which are used in high temperature firing at 260 ° C. or higher.
Maintains heat-resistant adhesion to various metals such as iron, stainless steel, aluminum, zinc plating, steel plate, copper, brass for a long time,
It is an object of the present invention to provide a heat-resistant coating base treatment agent having excellent safety.

[0006]

The heat-resistant coating base treatment agent for metal of the present invention comprises (a) the following general formula (I):

[0007]

[Chemical 2]

(Wherein R ¹ is a divalent hydrocarbon group having 1 to 4 carbon atoms, R ² R ³ is a monovalent hydrocarbon group having 1 to 4 carbon atoms, A 2
Is a hydrogen atom or an aminoalkyl group, and m is a number of 1 or 0), and (b) SiO ₂ / M ₂ O
(M represents a metal atom selected from lithium, sodium and potassium) A silicate aqueous solution having a molar ratio of 0.5 to 4, and (a) an aminoalkylalkoxysilane hydrolysis product, and (b) The weight ratio with the silicate is 1/20
It is composed of components that are synthetically reacted in the range of 10 to 10.

The hydrolysis product of aminoalkylalkoxysilane used in the present invention is represented by the following general formula (I).

[0010]

[Chemical 3]

(Wherein R ¹ is a divalent hydrocarbon group having 1 to 4 carbon atoms, R ² R ³ is a monovalent hydrocarbon group having 1 to 4 carbon atoms, A
Is a hydrogen atom or an aminoalkyl group, and m is a hydrolysis product of aminoalkoxysilane represented by 1 or 0), and the aminoalkylalkoxysilane is gradually added dropwise to hydrogen by stirring. Is synthesized.

Specific examples of aminoalkylalkoxysilanes include γ-aminopropyltrimethoxysilane and γ-aminopropyltrimethoxysilane.
Aminopropyltriethoxysilane, N- (β-aminoethyl) γ-aminopropyltrimethoxysilane, methyl (γ-aminopropyl) dimethoxysilane, methyl [N- (β-aminoethyl) γ-aminopropyl] dimethoxysilane, Examples thereof include methyl (γ-aminopropyl) dimethoxysilane.

The other component used in the present invention is an aqueous silicate solution containing at least one metal selected from lithium, sodium and potassium, and has a molar ratio of SiO ₂ / M _2.
O (M represents lithium, sodium, potassium)
It is a water-soluble compound in the range of 0.5 to 4, and specific examples include lithium silicates of ortho, sesqui, and meta, sodium, potassium, disodium disilicate, tetrasodium pentasilicate, disodium trisilicate, and disodium. An aqueous solution of tetrasilicate, dipotassium trisilicate, dipotassium tetrasilicate or the like can be mentioned, and it is usually provided at a Baume specific gravity concentration (15 ° C.) of about 30 to 60.

The weight ratio of the hydrolysis product of the aminoalkylalkoxysilane and the silicate is 1/2.
It is used in the range of 0-10, preferably 1 / 10-5. If the weight ratio is 1/20 or less, the adhesion to various heat-resistant paints, which is the main object of the present invention, cannot be improved, and if it is 10 or more, it becomes difficult to obtain a coating base material having excellent heat resistance.

For both, the required amount of aminoalkylalkoxysilane was dripped little by little into pure water or ion-exchanged water (may be city water) with stirring, and after hydrolysis, various silicate aqueous solutions were dripped little by little. And then synthesized.

[0016]

EFFECTS OF THE INVENTION A composition that imparts excellent heat resistance and adhesion to various metals of the present invention thus synthesized is diluted with a stock solution or water, and various degreasing agents or By immersing or spraying various metals such as iron, stainless steel, aluminum, zinc plating, steel plate, copper, brass whose surface has been cleaned by blasting, washing with water and drying, fluorine resin type, polyimide type, polyamide imide It can be used as an adhesion-improving coating base material having excellent heat resistance with various high-temperature baking type heat-resistant paints such as ceramics and ceramics.

The heat-resistant coating base treatment agent for metal of the present invention is
Improving heat resistance and adhesion between various heat-resistant paints of various high-temperature baking types and various metals, of course, it can be used as an epoxy / melamine, epoxy / phenol, acrylic /
General baking type paint such as melamine that is baked at a low temperature around 140 to 220 ° C. and iron, stainless steel, aluminum, zinc steel plate,
It can also be used as a base treatment agent for improving coating adhesion with various metals such as copper and brass, and as a base treatment agent for improving coating adhesion with various metals such as acrylic / urethane, polyester / urethane, and alkyd. It is a simple and non-polluting coating surface treatment agent that can be used as a coating surface treatment agent for various metals and can be widely used in the coating industry.

[0018]

EXAMPLES The present invention will be illustrated below with reference to various examples. Synthesis Example 1 40 g of γ-aminopropyltriethoxysilane was added dropwise to 200 ml of ion-exchanged water with stirring at 20 ° C. The hydrolysis reaction proceeded with heat generation, and a transparent γ-aminopropyltriethoxysilane hydrolysis product was obtained. Then, in this aqueous solution, 200 g of JIS sodium silicate No. 2 aqueous solution (SiO ₂ / Na ₂ O = 2.5) having a Baume specific gravity of 48 (15 ° C.)
Was stirred and dropped, and after completion of the dropping, stirring reaction was carried out at 70 ° C. for 2 hours to obtain a heat-resistant coating base treatment agent aqueous solution.

Synthesis Example 2 60 g of N- (β-aminoether) -γ-aminopropyltrimethoxysilane was added to 2000 ml of ion-exchanged water.
The mixture was added dropwise with stirring at 0 ° C. The hydrolysis reaction proceeded with exotherm, and a transparent hydrolysis product was obtained. After that, 40 g of JIS sodium silicate No. 3 aqueous solution (SiO ₂ / Na ₂ O = 3.1) having a Baume specific gravity of 40 (15 ° C.) was added dropwise to this aqueous solution with stirring. An aqueous coating base treatment agent solution was obtained.

Synthesis Example 3 Methyl (γ-aminopropyl) diethoxysilane 40 g
Was added dropwise to 2000 ml of ion-exchanged water with stirring at 20 ° C. The hydrolysis reaction proceeded with heat generation, and a transparent pale yellow methyl (γ-aminopropyl) diethoxycin hydrolysis product was obtained. After this, the Baume specific gravity of 30 is added to this aqueous solution.
Aqueous potassium silicate solution (15 ° C) (SiO ₂ / K ₂ O
= 2.5) 200 g with stirring and dropping, and after completion of dropping, 60 ° C. 3
Stirring reaction was carried out for a time to obtain a heat resistant coating base treatment agent.

Synthesis Example 4 30 g of γ-aminopropyltrimethoxycin was added dropwise to 2000 ml of deionized water at 20 ° C. with stirring. The hydrolysis reaction proceeded with generation of heat and a transparent hydrolysis product was obtained. After this, in this aqueous solution, the Baume specific gravity of 35 (15 ° C)
Lithium silicate aqueous solution (SiO ₂ / Li ₂ O = 3.
1) 30 g of the solution was stirred and dropped, and after completion of the dropping, the mixture was stirred and reacted at 80 ° C. for 4 hours to obtain a heat-resistant raw coating base treatment agent aqueous solution.

Example 1 and Comparative Example 1 An aluminum plate whose surface was cleaned by alkaline degreasing (JIS-
H-4000) with the heat-resistant coating base treatment agent according to the present invention of Synthesis Examples 1 to 4 at the treatment temperature and time shown in Table 1 after dipping treatment and drying, and then perfluoroalkyl ether type fluorine having a firing temperature of 280 ° C. Resin coating [Product name: Aflon Asahi Glass Co., Ltd.] is spray-coated and the initial temperature is 80 ° C 16
Table 1 shows the adhesiveness of goose stitches after being immersed in hot water for 5 hours and after being heat-deteriorated at 300 ° C. for 48 hours according to JIS-D-0202. As Comparative Example 1, the adhesiveness of the cross stitch using an aluminum plate that was only degreased under the same conditions was also shown.

[0023]

[Table 1]

Example 2 and Comparative Example 2 A stainless steel plate (S
US304) in a concentration of 10 wt% with the heat-resistant coating base treating agent of the present invention of Synthesis Examples 1 to 4 under the treatment conditions shown in Table 2 after dipping, drying, and firing at 260 ° C. CRM coat Okuno Seiyaku Kogyo Co., Ltd.] by spray coating and after initial immersion in warm water at 80 ° C. for 168 hours, heat resistance deterioration at 300 ° C. for 48 hours.
It was evaluated by IS-D-0202 and shown in Table 2. Comparative example 2
As a result, a blast-treated stainless plate was coated under the same conditions, and the adhesiveness of the eyelet eye was also described.

[0025]

[Table 2]

Example 3 and Comparative Example 3 A brass plate cleaned by alkaline degreasing had a concentration of 15 w.
t% of the heat-resistant coating base treating agent according to the present invention of Synthesis Examples 1 to 4 under the treatment conditions shown in Table 3 after dipping and drying, and at a firing temperature of 300 ° C., a polyamide-imide type coating [trade name S-6
100 Sun S Co., Ltd.] is spray coated,
After the initial deterioration of warm water at 80 ° C. for 168 hours and the deterioration of heat resistance at 300 ° C. for 48 hours after heat deterioration, the adhesiveness of each eyelet was evaluated according to JIS-D-0202 and shown in Table 3. As Comparative Example 3, a brass plate only degreased with alkali was coated under the same conditions, and the adhesiveness of the cross stitch was also described.

[0027]

[Table 3]

Example 4 and Comparative Example 4 An aluminum plate cleaned by alkaline degreasing (JIS-H-
4000) with a coating base treatment agent of the present invention of Synthesis Examples 1 to 4 having a concentration of 10 wt% under the treatment conditions shown in Table 4 after dipping treatment and drying at an calcination temperature of 180 ° C. at an epoxy / phenolic coating composition [trade name AC Coat, manufactured by Osaka Varnish Co., Ltd.] was spray coated, and the adhesiveness of each eyelet after the initial deterioration in hot water of 80 ° C. was evaluated according to JIS-D-0202, and shown in Table 4. As Comparative Example 4, an aluminum plate that had been only degreased with alkali was applied under the same conditions, and the adhesiveness of the cross stitch was also described.

[0029]

[Table 4]

Claims (1)

[Claims] 1. (a) The following general formula (I): (Wherein R ¹ is a divalent hydrocarbon group having 1 to 4 carbon atoms, R ² ,
R ³ is a monovalent hydrocarbon group having 1 to 4 carbon atoms, A is a hydrogen atom or an aminoalkyl group, and m is a number of 1 or 0) and a hydrolysis product of an aminoalkylalkoxysilane. , (B) SiO ₂ / M ₂ O (M represents a metal atom selected from lithium, sodium, and potassium) composed of an aqueous silicate solution having a molar ratio of 0.5 to 4,
A heat-resistant coating base treatment agent for metal, which comprises a synthetic reaction product of the aminoalkylalkoxysilane hydrolysis product (a) and the silicate (b) in a weight ratio of 1/20 to 10 .