JPH0577065A - Method for joining steel material for building - Google Patents

Abstract

PURPOSE:To increase the coefft. of friction to >=0.45 and to allow one coat finishing by previously coating joint surfaces with a specific coating material in the method for joining steel material members by a high strength bolt friction joining method. CONSTITUTION:The organo-alkoxysilane in which the polysiloxane as the constituting component of the coating material consists of 100: 0 to 40 ratios based on the weight of the compd. expressed by general formula RSi(OR')3 and the compd. expressed by R2Si(OR')2 is used in accordance with the conventional method. For example, this organo-alkoxysilane is formed by liberating alcohol by a hydrolysis reaction in an acidic aq. medium and inducing a polycondensation reaction so as to act as a binder. The coefft. of friction of the resulted coating film is maintained at >=0.45. Then, the colloidal silica and colloidal alumina improve the storage stability of the coating material and allow the coating to a larger thickness. A packing material is compounded with this coating material in order to obtain the coating film which is thick and is crackfree.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for joining steel members by a high-strength bolt friction joining method, and relates to a method for joining steel members in which a joint surface of the members is provided with a high friction coefficient by painting.

[0002]

2. Description of the Related Art Buildings are usually constructed by joining steel members by a high strength bolt friction joining method, a rivet joining method, a welding method, etc. The high-strength bolt friction welding method occupies the mainstream because a joint portion having high rigidity can be obtained. In this high-strength bolt friction welding method, steel members a and a'are tightened with high-strength bolts 1, nuts 2 and washers 3 and 3'as shown in FIG. This is a joining method in which stress is transmitted by frictional force. Therefore, the high strength bolt friction joint surface is usually required to have a friction coefficient of 0.45 or more.

By the way, in order to obtain a friction coefficient of 0.45 or more, a method of forcibly rusting after blasting the joint surface of a conventional steel member, and a method of coating an inorganic zinc rich paint (b) The method (c) of spraying zinc was adopted. However, in the method (a), it is necessary to apply a normal anticorrosive paint to the entire surface after joining and assembling the steel members for the purpose of rust prevention, and there is a problem that the workability of painting is poor.

In the method (b), the inorganic zinc-rich paint is usually applied to the entire surface including the joint surface of the steel member in advance. However, the zinc-rich paint film has white rust and has a finished appearance. Because it is bad, after joining the steel members and assembling,
Furthermore, there is a problem that it is necessary to apply an organic topcoat paint, the number of painting processes is increased, and the workability of painting is poor. It is inappropriate to apply an organic paint using an organic binder to the joint surface before joining the steel members, because the friction coefficient of the high strength bolt friction joint surface will drop to about 0.2.

Further, the method (c) has the same problem as the method (b) because white rust is likely to occur on the sprayed coating.
In view of such a situation, the present invention makes it possible to set the friction coefficient to 0.45 or more, and does not require the application of the organic top-coat paint after joining and assembling the steel members, that is, a one-coat finish. The purpose is to provide a possible method.

[0006]

As a result of earnest research, the present inventors have found that the above object can be achieved by pre-painting a specific coating on the joint surface, and have completed the present invention.
That is, the present invention relates to a method for joining a steel member for construction by a high-strength bolt friction joining method, in which (a) (i) the general formula RSi (OR ') ₃ (wherein R is an organic group having 1 to 8 carbon atoms, R'is 1 to 8 carbon atoms
5 is an organic group. ) And a compound of the general formula R ₂ Si (OR ′) ₂ (wherein R and R ′ are as defined above) (100: 0-40) (weight Polysiloxane having a weight average molecular weight of 500 to 50,000 (calculated as organoalkoxysilane) obtained by condensing organoalkoxysilane having a ratio of (standard).
0 parts by weight, (b) colloidal silica and / or colloidal alumina (as solid content) 5 to 50 parts by weight (c) filler 5 to 800 parts by weight, and (d) coating material consisting of the balance of solvent It is characterized by the joining method of steel members for construction.

The present invention will be described in detail below. Polysiloxane which is a component of the paint used in the present invention the general formula RSi (OR ') a compound represented by ₃ and R ₂ Si (OR') ₂
An organoalkoxysilane having a ratio of (100: 0 to 40) (weight basis) with a compound represented by the following formula is used to liberate an alcohol by a hydrolysis reaction in an acidic aqueous medium and to cause a polycondensation reaction. It is formed, acts as a binder, and keeps the friction coefficient of the obtained coating film at 0.45 or more.

In the above general formula, R is an organic group having 1 to 8 carbon atoms, such as an alkyl group such as a methyl group, an ethyl group, an n-propyl group, an i-propyl group, or a γ-chloropropyl group. , Vinyl group, 3,3,3-trifluoropropyl group, γ-glycidoxypropyl group, γ-methacryloxypropyl group, γ-mercaptopropyl group, phenyl group, 3,4-epoxycyclohexylethyl group, γ
A typical example is an aminopropyl group.

R'in the above general formula is an organic group having 1 to 5 carbon atoms, such as methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, sec-butyl group,
Examples thereof include tert-butyl group and acetyl group. Particularly in the present invention, those containing CH ₃ Si (OR ′) ₃ as a main component are preferable. Further, the organoalkoxysilane has the general formula RSi
The compound represented by (OR ') ₃ may be used alone, but in order to improve the crack resistance and thick film resistance, the compound represented by the general formula R ₂ Si (OR') ₂
The compound shown by can be used together within the above range.
If it exceeds this range, the drying property is lowered, the hardness of the obtained coating film is lowered, and the friction coefficient is lower than 0.45, which is not preferable. The weight average molecular weight of polysiloxane (calculated as organoalkoxysilane) is preferably 500 to 50,000 in terms of polystyrene.
If the molecular weight is smaller than the above range, the adhesiveness of the resulting coating film is deteriorated. On the other hand, if it is too large, the storage stability is deteriorated due to gelation of the paint and the adhesiveness of the coating film is also deteriorated.

Colloidal silica and colloidal alumina, which are constituents of the paint used in the present invention, improve the storage stability of the paint and enable thickening, and the hardness and heat resistance of the resulting coating film. To improve the composition. Colloidal silica is a dispersion in which silicic acid anhydride is dispersed in a hydrophilic organic solvent, and usually has an average particle size of about 5 to 30 m.
μ, solid content of about 10 to 40% by weight, water content 4
It is preferably less than or equal to wt%. As commercially available products, organosilica sol IPA-ST, organosilica sol ETC-
ST, organosilica sol Snowtex 30 (all manufactured by Nissan Chemical Industry Co., Ltd.), Oscar (manufactured by Catalysts & Chemicals Industry Co., Ltd.) and the like can be mentioned.

Colloidal alumina has a pH of water as a solvent.
It is an alumina sol of 2.5 to 6 and contains about 5 to 25% by weight of alumina, boehmite and the like, and an acid such as nitric acid, hydrochloric acid or acetic acid is used as a stabilizer.
It is 200 mμ. As commercial products, alumina sol-100, alumina sol-200, alumina sol-52
0 (above manufactured by Nissan Chemical Industries, Ltd.), aluminum oxide C (manufactured by Degussa) and the like.

The amount of colloidal silica and / or colloidal alumina is 5 to 100 parts by weight of polysiloxane (calculated as organoalkoxysilane) in terms of solid content.
It is suitable to add 50 parts by weight. If the blending amount is less than the above range, the storage stability of the coating composition becomes poor, it becomes difficult to form a thick film, the hardness of the obtained coating film becomes insufficient, and cracks easily occur. On the other hand, when the amount is more than the above range, the viscosity is increased, the drying property is deteriorated, and cracks are more likely to occur.

The filler, which is a constituent of the paint used in the present invention, is added in order to obtain a thick film free from cracks. Titanium oxide, valve stem, iron oxide yellow, iron oxide black. , Color pigments typified by carbon black, cobalt oxide, zinc oxide, etc .; zinc molybdate, condensed aluminum phosphate, zinc phosphate, potassium chromate, zinc chromate, rust-preventive pigments typified; calcium carbonate, silica, Fillers such as extender pigments typified by zirconia, alumina, aluminum hydroxide, diatomaceous earth and the like can be mentioned as representative ones, and these can be used alone or as a mixture of two or more kinds.

The amount of the filler to be blended is appropriately 5 to 800 parts by weight per 100 parts by weight of polysiloxane (calculated as organoalkoxysilane). As a solvent which is a constituent of the paint used in the present invention, a mixed solvent of water for a hydrolysis reaction and alcohols effective for preventing gelation during hydrolysis is suitable. Further, these solvents also serve as a dispersion medium for colloidal silica, colloidal alumina and filler.

The alcohols include methanol,
Representative examples include ethanol, n-propyl alcohol, i-propyl alcohol, sec-butyl alcohol, ethylene glycol, ethylene glycol monobutyl ether, and ethylene glycol monoethyl ether acetate. The amount of these solvents is usually in the range of 10 to 70 in terms of the solid content of the coating in consideration of the coating workability and the reactivity.
It is suitable to mix them in such a manner that the weight% is obtained.

The paint used in the present invention contains the above-described components as essential constituents, and if necessary, the pH of the paint.
Acid, organic acid, other surfactants, silane coupling agents, titanium coupling agents,
It comprises various additives such as alkali metal salts, amines and organic tin compounds. Next, the method of the present invention will be described.

The steel member for construction referred to in the present invention is a steel member applied to small buildings such as warehouses, private houses and shops, and the surface of the steel member before being joined by the high strength bolt friction joining method. Surface treatment, if necessary, and after applying a primer to the parts other than the joint, surface treatment such as pre-plast treatment, pickling treatment (and zinc phosphate treatment if necessary),
Further, if necessary, a primer is applied to a portion other than the joint surface, and then the above-mentioned paint is applied to the entire surface of the steel member. Only the joints of the steel members may be painted, but it is necessary to join the steel members, assemble them, and then paint separately.
Before joining the steel members, it is desirable to coat the entire surface including the joints.

That is, since the coating material used in the present invention is a coating film having a high friction coefficient similar to that of the zinc-rich coating film, white rust is not generated unlike the zinc-rich coating film, and the coating film has a good appearance. By coating the entire surface of the steel material, the above 1
The coat finish is possible, and the painting after assembling can be omitted. As a coating method for steel members, usual methods such as brush coating, roller coating, air spray coating, airless spray coating and electrostatic spray coating can be adopted.
A cured coating film can be formed at a temperature of room temperature to 300 ° C. The coating is applied to a dry film thickness of 5 to 200 μm, preferably 30 to 150 μm.

According to the present invention, a coating film having a coefficient of friction of 0.45 or more is thus formed on at least the joint surface of the steel member.
Desirably, after the entire surface is applied, the steel members can be joined and assembled by the high-strength bolt friction joining method to construct a building.

[0020]

According to the method of the present invention, when the steel members are joined by the high-strength bolt friction joining method, the joining surface of the members can be made to have a friction coefficient of 0.45 or more. White rust does not occur unlike the used inorganic zinc rich paint and zinc spraying, and the appearance of the coating film is good. Therefore, if the steel members are pre-painted not only on the joint surface but on the entire surface, After joining and assembling, there is no need to apply a top coat, so the work process can be shortened.

[0021]

EXAMPLES The present invention will now be described in more detail with reference to examples. In the examples, "parts" and "%" are shown by weight. Preparation of coating composition In a reactor equipped with a reflux condenser and a stirrer, 100 parts of methyltrimethoxysilane, 100 parts of isopropyl alcohol-dispersed colloidal silica (solid content 20%), 30 parts of water and 150 parts of isopropyl alcohol were added. Mix, 70 ℃, 2
After reacting for a period of time, a coating composition (A) containing a polysiloxane having a weight average molecular weight of 1200 and colloidal silica was prepared.

By the same procedure as described above, coating compositions (B) to (G) were prepared by substituting organoalkoxysilane, colloidal silica, colloidal alumina, water and isopropyl alcohol as shown in Table 1.

[0023]

[Table 1]

Note 1) "Isopropanol silica sol"
(Manufactured by Nissan Chemical Industries, Ltd.), isopropanol dispersion liquid with a solid content of 20% Note 2) "Alumina sol-100" (manufactured by Nissan Chemical Industries, Ltd.), aqueous dispersion liquid with a solid content of 20% Examples 1-5 and Comparative Examples 1- 4 The paints shown in Table 2 were shot-blasted steel plates (rust grade Sa 2.5, surface roughness average (Ra) 50μ, maximum (Rmax) 8
0 μ) was air-spray coated to a dry film thickness of 50 μm and baked at 150 ° C. for 30 minutes. Comparative Examples 5 to 6 As Example 1, except that a commercially available epoxy resin-based paint (“Eponics # 20” manufactured by Dainippon Paint Co., Ltd.) and an inorganic zinc-rich paint (“Zettar OL” manufactured by Dainippon Paint Co., Ltd.) were used. It was coated in the same manner and naturally dried for 7 days.

The test plates and the uncoated test plates obtained in Examples 1 to 5 and Comparative Examples 1 to 6 were subjected to friction coefficient measurement, adhesion test and salt spray test (48 hours), and the results are shown in Table 2.
It is shown in the bottom row.

[0026]

[Table 2]

As is clear from the test results shown in Table 2, the friction coefficient of the test plate obtained by the method of the present invention is 0.45.
In addition, the adhesiveness and corrosion resistance were good, and the film had a good appearance without cracks. On the other hand, Comparative Example 1 using a coating material containing an excessive amount of filler had poor corrosion resistance and adhesion.

Comparative Example 2 using a coating material containing a large amount of tetraethoxysilane represented by the general formula Si (OR) ₄ as the organoalkoxysilane, and Comparative Example using a coating material containing no colloidal silica or alumina. No. 4 did not form a film and had no practical value. Further, Comparative Example 3 which uses a coating material in which dimethyldimethoxysilane represented by the general formula R ₂ Si (OR ′) ₂ is used in excess is poor in drying property and sticky to the coating film and has no practical value. there were.

Further, Comparative Example 5 using the organic paint had a small friction coefficient and was not suitable for the high strength bolt friction welding method. In Comparative Example 6 using the inorganic zinc-rich paint, the coefficient of friction was satisfied, but white rust was generated and top coating was required.

[Brief description of drawings]

FIG. 1 shows a high strength bolt friction joint.

[Explanation of symbols]

 a, a'Steel material 1 High-strength bolt 2 Nut 3, 3'Washer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mami Emi 10-31-1-308 Hattakitamachi, Sakai City, Osaka Prefecture (72) Inventor Hiroyuki Mishima 3-chome, Kaida 3-chome, Nagaokakyo, Kyoto Prefecture Roy Yal Heights Fujita (72) Inventor Teruyuki Takahashi 2-2-1024 Wakaba-cho, Ashiya City, Hyogo Prefecture (72) Inventor Makoto Nagamine 1225 Uenohira, Nakazai-ji, Gino-cho, Gamo-gun, Shiga Prefecture Daifuku Shiga Works, Ltd. (72) Shigeru Kagayama, Tokyo 2-14-5 Shiba, Minato-ku Daifuku Co., Ltd. Tokyo Head Office (72) Inventor Tokio Takeyama 2-14-5 Shiba, Minato-ku Shiba Co., Ltd. Tokyo Head Office (72) Inventor Ken Sasaki Shiga 1225 Kaminohira, Nakazai-ji, Hino-cho, Gamo-gun, Fukushima Prefecture Daifuku Shiga Works

Claims (1)

[Claims] 1. A method for joining steel members by a high-strength bolt friction joining method, wherein at least a joining surface of the members is
In advance, (a) (i) the general formula RSi (OR ′) ₃ (wherein R is an organic group having 1 to 8 carbon atoms, R ′ is 1 to 1 carbon atoms).
5 is an organic group. ) And a compound represented by the general formula R ₂ Si (OR ′) ₂ (wherein R and R ′ are as defined above) (100: 0-40) (weight Polysiloxane having a weight-average molecular weight of 500 to 50,000 (calculated as organoalkoxysilane) obtained by condensing an organoalkoxysilane having a ratio of (standard)
100 parts by weight, (b) colloidal silica and / or colloidal alumina (as solid content) 5 to 50 parts by weight (c) filler 5 to 800 parts by weight, and (d) coating material consisting of the balance of solvent A method for joining steel members for construction, which is characterized in that