ORGANOSILICON COMPOUND, METHOD FOR PRODUCING SAME AND METAL SURFACE TREATMENT AGENT USING SAME

Abstract

An organosilicon compound represented by general formula (1). The present invention is able to provide an organosilicon compound which has excellent adhesion during processing and high bonding strength, while exhibiting antirust corrosion resistance at high levels, and which is useful as a metal surface treatment agent.

##STR00001##

(In the formula, R represents a hydrolyzable group; R′ represents an alkyl group; A represents an alkylene group; R.sup.1 and R.sup.2, R.sup.2 and R.sup.3, or R.sup.3 and R.sup.4 among the R.sup.1, R.sup.2, R.sup.3 and R.sup.4 moieties may combine together to form an aliphatic or aromatic ring skeleton, and in cases where a ring skeleton is not formed, each one of the R.sup.1, R.sup.2, R.sup.3 and R.sup.4 moieties independently represents a hydrogen atom or an alkyl group; and m represents a number of 1-3.)

Claims

1. An organosilicon compound having the general formula (1): ##STR00017## wherein R is a hydrolyzable group, R′ is a C.sub.1-C.sub.4 alkyl group, A is a C.sub.1-C.sub.8 alkylene group, R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are each independently hydrogen or a C.sub.1-C.sub.6 alkyl group when they do not form a ring structure, or a pair of R.sup.1 and R.sup.2, R.sup.2 and R.sup.3, or R.sup.3 and R.sup.4 may bond together to form an aliphatic or aromatic ring structure, and m is an integer of 1 to 3.

2. The organosilicon compound of claim 1, having the general formula (2): ##STR00018## wherein R.sup.5 is a C.sub.1-C.sub.10 alkyl or C.sub.6-C.sub.10 aryl group, R.sup.1, R.sup.2, R.sup.3, R.sup.4 and m are as defined above, and Me is methyl.

3. A method for producing the organosilicon compound of claim 1 or 2, comprising the step of reacting an organosilicon compound having the general formula (3): ##STR00019## wherein R, R′, A and m are as defined above, with a benzotriazole compound having the general formula (4): ##STR00020## wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are as defined above.

4. A metal surface treating composition comprising the organosilicon compound of claim 1 or 2 as an active ingredient.

5. The metal surface treating composition of claim 4, further comprising an alkoxysilane having the general formula (13) or a partial hydrolytic condensate thereof,
R.sup.6.sub.xSi(OR.sup.7).sub.4-x  (13) wherein R.sup.6 is a substituted or unsubstituted, C.sub.1-C.sub.20 monovalent hydrocarbon group, R.sup.7 is a substituted or unsubstituted, C.sub.1-C.sub.8 monovalent hydrocarbon group, and x is an integer of 0 to 3.

6. The metal surface treating composition of claim 4, further comprising an organic titanate.

7. The metal surface treating composition of claim 4, further comprising water dispersible silica or organic solvent dispersible silica.

8. The metal surface treating composition of claim 4, further comprising a compound of at least one metal selected from the group consisting of Fe, Zr, Ti, V, W, Mo, Al, Sn, Nb, Hf, Y, Ho, Bi, La, Ce, and Zn.

9. The metal surface treating composition of claim 4, further comprising a thiocarbonyl-containing compound.

10. The metal surface treating composition of claim 4, further comprising a water soluble or water dispersible resin.

11. The metal surface treating composition of claim 4, further comprising a phosphate ion.

12. A method for the surface treatment of a steel member, comprising the step of treating a surface of a steel member with the metal surface treating composition of claim 4.

13. A method for preparing a coated steel member, comprising the steps of treating a steel member with the metal surface treating composition of claim 4 and forming an overcoat layer on the treated member.

14. A surface-treated steel member obtained by the surface treating method of claim 12.

15. A coated steel member obtained by the preparation method of claim 13.

Description

EXAMPLE

[0080] Examples and Comparative Examples are given below by way of illustration and not by way of limitation. In Examples, all parts are by weight, Me stands for methyl, and IR is an abbreviation of infrared spectroscopy.

Example 1

Method of Producing Organosilicon Compound (5)

[0081] A 1-L separable flask equipped with a stirrer, reflux condenser, dropping funnel and thermometer was charged with 118.1 g (1 mol) of benzotriazole and 200 g of toluene and heated at 40° C. To the flask, 205.3 g (1 mol) of 3-isocyanatopropyltrimethoxysilane was added dropwise. The contents were stirred at 100° C. for 1 hour. On IR analysis, the complete disappearance of absorption peaks assigned to an isothiocyanate group of the reactant was observed as the end of reaction. The solvent was then removed, yielding the reaction product as a yellow liquid. By gel permeation chromatography (GPC), the reaction product was identified to be a single compound having the following formula (5).

##STR00014##

Example 2

Method of Producing Organosilicon Compound (8)

[0082] A 1-L separable flask equipped with a stirrer, reflux condenser, dropping funnel and thermometer was charged with 133.2 g (1 mol) of 5-methylbenzotriazole and 200 g of toluene and heated at 40° C. To the flask, 205.3 g (1 mol) of 3-isocyanatopropyltrimethoxysilane was added dropwise. The contents were stirred at 100° C. for 1 hour. On IR analysis, the complete disappearance of absorption peaks assigned to an isothiocyanate group of the reactant was observed as the end of reaction. The solvent was then removed, yielding the reaction product as a yellow liquid. By GPC, the reaction product was identified to be a single compound having the following formula (8).

##STR00015##

Example 3

Method of Producing Organosilicon Compound (9)

[0083] A 1-L separable flask equipped with a stirrer, reflux condenser, dropping funnel and thermometer was charged with 133.2 g (1 mol) of 6-methylbenzotriazole and 200 g of toluene and heated at 40° C. To the flask, 205.3 g (1 mol) of 3-isocyanatopropyltrimethoxysilane was added dropwise. The contents were stirred at 100° C. for 1 hour. On IR analysis, the complete disappearance of absorption peaks assigned to an isothiocyanate group of the reactant was observed as the end of reaction. The solvent was then removed, yielding the reaction product as a yellow liquid. By GPC, the reaction product was identified to be a single compound having the following formula (9).

##STR00016##

Example 4

[0084] A metal surface treating composition was prepared by adding 10 g (as nonvolatile) of organosilicon compound (5) in Example 1 to a solvent mixture of 990 g of methanol and 10 g of water and stirring them at room temperature for 5 minutes. Onto a commercial hot dip galvanized steel plate of 70×150×0.4 mm (Nippon Testpanel Co., Ltd.) which had been degreased and dried, the metal surface treating composition was applied by a bar coater No. 20 so as to form a dry coating of 10 m thick. The treated plate was dried at a metal surface temperature of 105° C. for 10 minutes. A V/P pigmented non-chromate primer was applied onto the treated plate by a bar coater No. 16 so as to form a dry coating of 5 μm thick and dried at a metal surface temperature of 215° C. for 5 minutes. A topcoat Flexicoat 1060 (polyester topcoat material, Nippon Paint Co., Ltd.) was applied onto the primer-coated plate by a bar coater No. 36 so as to form a dry coating of 15 m thick and dried at a metal surface temperature of 230° C., obtaining a test plate. The test plate was evaluated for bend-following adhesion, deep drawing resistance, and corrosion resistance by the methods described below, with the results shown in Table 1.

Examples 5 and 6

[0085] Metal surface treating compositions were prepared as in Example 4 except that the compound in Example 1 was changed to the compounds in Examples 2 to 4. Using these metal surface treating compositions, test plates were fabricated as in Example 4, and similarly evaluated. The results are shown in Table 1.

Examples 7 to 13

[0086] Metal surface treating compositions were prepared as in Example 4 except that the compound in Example 1, the type and concentration of silane compound, and the concentrations of organic titanate, water dispersible silica, zirconium ion, thiocarbonyl-containing compound, water soluble resin and phosphate ion were combined as shown in Table 1. Using these metal surface treating compositions, test plates were fabricated as in Example 4, and similarly evaluated. The results are shown in Table 1.

Comparative Examples 1 to 3

[0087] Metal surface treating compositions were prepared as in Example 4 except that the compounds in Examples 1 to 3 were not used and the type and concentration of silane compound and the concentrations of organic titanate, water dispersible silica, zirconium ion, thiocarbonyl-containing compound, water soluble resin and phosphate ion were combined as shown in Table 1. Using these metal surface treating compositions, test plates were fabricated as in Example 4, and similarly evaluated. The results are shown in Table 1.

Comparative Example 4

[0088] A test plate was fabricated as in Example 4 except that a commercial chromate treating agent for coating use (resin-containing type) was applied and dried in a chromium coating weight of 20 mg/m.sup.2 instead of the metal surface treating composition, and a chromium-containing primer (a strontium chromate pigment-containing primer) was used. The test plate was similarly evaluated, with the results shown in Table 1.

[0089] Notably, the commercial products shown below were used as the silane compound, organic titanate, water dispersible silica, zirconium ion-providing compound, thiocarbonyl-containing compound, water soluble resin and phosphate ion-providing compound in Table 1.

[Silane Compound]

[0090] A: KBM-903 [0091] (γ-aminopropyltrimethoxysilane; Shin-Etsu Chemical Co., Ltd.)

[0092] B: KBM-403 [0093] (γ-glycidoxypropyltrimethoxysilane; Shin-Etsu Chemical Co., Ltd.)

[0094] C: reaction product of KBM-403 and benzotriazole [0095] (synthesized with reference to JP-A H06-279463)

[Organic Titanate]

[0096] Titanium tetraisopropoxide

[Water Dispersible Silica]

[0097] Methanol silica sol (Nissan Chemical Industries, Ltd.)

[Zirconium Ion-Providing Compound]

[0098] Zircosol AC-7

[0099] (ammonium zirconium carbonate; Daiichi Kigenso Kagaku Kogyo Co., Ltd.)

[Thiocarbonyl-Containing Compound]

[0100] Thiourea

[Water Soluble Resin]

[0101] Polyacrylate (weight average molecular weight 1,000,000)

[Phosphate Ion-Providing Compound]

[0102] Phosphoric acid

[Evaluation Methods]

[0103] In Examples 4 to 13 and Comparative Examples 1 to 4, bend-following adhesion, deep drawing resistance and corrosion resistance were evaluated in accordance with the following methods and criteria.

Bend-Following Adhesion

[0104] Using a conical mandrel tester in an environment of 20° C., the test plate was bent through 180° with interposition of a spacer of 2 mm in diameter. To the bent region, adhesive tape was applied and peeled 3 times. The degree of peeling was examined under a 20× magnifier loupe and rated according to the following criterion.

[0105] A: no cracks

[0106] B: cracks all over the bent region

[0107] C: peeled area is less than 20% of the bent region

[0108] D: peeled area is from 20% to less than 80% of the bent region

[0109] E: peeled area is at least 80% of the bent region

Deep Drawing Resistance

[0110] The cupping test was performed in an environment of 20° C. under conditions: drawing ratio 2.3, blank holding pressure 2 t, punch radius 5 mm, die shoulder radius 5 mm, and oil-free. The width of peeled film from the crosscut was measured and rated according to the following criterion.

[0111] A: blister width less than 1 mm

[0112] B: blister width from 1 mm to less than 2 mm

[0113] C: blister width from 2 mm to less than 3 mm

[0114] D: blister width from 3 mm to less than 5 mm

[0115] E: blister width 5 mm or more

Corrosion Resistance

(Crosscut)

[0116] A crosscut was scribed on the test plate, which was subjected to the salt spray test according to JIS Z 2371 for 500 hours. The width of blister on one side of the cut was measured and rated according to the following criterion.

[0117] A: blister width 0 mm

[0118] B: blister width from more than 0 mm to less than 1 mm

[0119] C: blister width from 1 mm to less than 3 mm

[0120] D: blister width from 3 mm to less than 5 mm

[0121] E: blister width 5 mm or more

(Edge)

[0122] The test plate was subjected to the salt spray test according to JIS Z 2371 for 500 hours. The width of blister at the upper burr edge was rated according to the same criterion as in the crosscut test.

TABLE-US-00001 TABLE 1 Formulation of metal surface treating composition Phos- Water ZR Thio- ophate Test results Silane dis- ion- carbonyl- Water ion- Corrosion coupling Silane Organic persible providing containing soluble providing Bend- Deep reistance agent compound titanite silica compound compound resin compound following drawing Cross- No. Type g/l Type g/l g/l g/l g/l g/l g/l g/l adhesion reistance Cut Edge Example 4 (5) 10 A B A A 5 (8) 10 A B A A 6 (9) 10 A B A A 7 (5) 10 A 3 A B A A 8 (5) 10 A 3 4 A B A A 9 (5) 10 A 3 4 1 A B A A 10 (5) 10 A 3 4 1 0.5 A B A A 11 (5) 10 A 3 4 1 0.5 2.5 A B A A 12 (5) 10 A 3 4 1 0.5 2.5 25 A A A A 13 (5) 10 A 3 4 1 0.5 2.5 25 0.5 A A A A Compar- 1 A 10 4 1 0.5 2.5 25 0.5 E E D D ative 2 B 10 4 1 0.5 2.5 25 0.5 E E D D Example 3 C 10 4 1 0.5 2.5 25 0.5 C C B B 4 chromate treating agent for coating use C C B C

[0123] The results of Examples and Comparative Examples demonstrate that the metal surface treating composition of the invention forms a coating which exhibits good rust prevention and tight adhesion to substrates.