JPH11209661A - Tar-epoxy coating composition and method for visual recognition of coating film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a tar-epoxy coating compsn. which enables the boundaries between repaired and unrepaired parts of a coating film to be recognized by incorporating. into the same, a fluorescent dye which is invisible in visible rays but emits light by ultraviolet rays. SOLUTION: A fluorescent dye which is invisible in visible rays but emits light by ultraviolet rays (e.g. 2,5-bis[5'-t-butylbenzoxazolyl (2)]thiophene) pref. in an ant. of 0.1-20 pts.wt. is incorporated into 100 pts.wt. tar-epoxy coating compsn. comprising 15-50 wt.% tar pitch having a softening point of 60 deg.C or lower, 7-25 wt.% epoxy resin, 10-40 wt.% inorg. powder (e.g. a silica powder), 15-50 wt.% high-boiling tar oil freed from crystals and mainly comprising a heavy oil having a b.p. of 250 deg.C or higher, and 0.5-10 wt.% curing agent or cure accelerator (e.g. an amine or a phenol). Thus obtd. coating compsn. enables repaired parts to be effectively recognized when a repair work is continued for a long term or when partial repair works are done at intervals of some years.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tar epoxy coating composition and a method for visually confirming a coating film. The present invention relates to a tar epoxy coating composition capable of distinguishing a boundary with an unrepaired portion and a method for visually confirming a coating film.

[0002]

2. Description of the Related Art In a repair work for a place where a tar epoxy paint is coated, a repair work is often performed for a long time or many days, or a partial repair is often performed every several years. In such a case, after repairing a part of the surface coated with tar epoxy paint, peel off and repair other than the repaired part, or peel off the repaired part several years later and repair it It is necessary to repeat such repair, but in such a case, it is difficult to distinguish the boundary between the repaired portion and the unrepaired portion. Especially,
In repairs performed under illumination, such as repairing ductile segments in subways or cast iron frames in tunnels, the boundaries between black coatings can be distinguished with the naked eye in bright outdoor conditions. It was almost impossible to identify because it was difficult to obtain bright lighting like outdoors.

[0003]

In the case of repair work for a place where tar epoxy paint is coated, when the repair work is performed for a long time or for many days, or when the repair is partially performed every several years, Before the break, it is necessary to identify the boundary between the part repaired the day before or several years ago and the unrepaired part.

[0004] The present invention provides a tar epoxy coating composition capable of identifying a repaired portion of a tar epoxy coating film, and thus a boundary between a repaired portion and an unrepaired portion, and It is an object of the present invention to provide a method for visually recognizing a coating film obtained using such a coating composition.

[0005]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, the above-mentioned problems are solved by adding a specific fluorescent dye to the tar epoxy paint. Thus, the present invention has been completed.

That is, the tar epoxy coating composition of the present invention is characterized by containing a fluorescent dye which is invisible under visible light but emits light by ultraviolet light. Further, the method for visually confirming a coating film of the present invention is characterized in that a coating film formed by applying the above-described tar epoxy coating composition containing a fluorescent dye is irradiated with ultraviolet light to cause the coating film to emit light. .

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The tar epoxy paint used in the present invention (in the present specification, when no fluorescent dye is contained, is described as a tar epoxy paint, and when it contains a fluorescent dye, is described as a tar epoxy paint composition), Alternatively, it is obtained by blending an inorganic powder or the like with a composition comprising pitch, an epoxy resin, and a curing agent, and is widely used as a heavy-duty anticorrosive paint.

[0008] Such a tar epoxy paint is preferably 15 to 50% by weight of soft pitch, epoxy resin 7
25 to 25% by weight, inorganic powder 10 to 40% by weight, high boiling tar oil 15 to 50% by weight, hardener or hardening accelerator 0.5 to
And those containing 10% by weight.

The above soft pitch is a tar pitch having a softening point of 60 ° C. or less, and this soft pitch provides long-term corrosion protection. As the above epoxy resin, an epoxy resin such as a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a phenol novolak type epoxy resin and the like can be used.

As the above-mentioned inorganic powder, talc powder, titanium oxide powder, zinc oxide powder, silica powder and the like can be used. As the above high boiling tar oil, tar heavy oil having a boiling point of 250 ° C or more as a main component, or heavy oil having a boiling point of 250 ° C or more when decomposing pitch, coal tar, coal, or the like is used. A tar oil as a main component can be used, but it is preferable to use a decrystallized oil which does not precipitate crystals even when cooled to room temperature to about 0 ° C.

As the above-described curing agent or curing accelerator, those commonly used as curing agents or curing accelerators for epoxy resins can be used. For example, amines such as triethylenetetramine and phenols such as 2,4,6-tri (dimethylaminomethyl) phenol can be used. The type and amount of the curing agent or the curing accelerator to be used affect the curing time. When a curing agent or a curing accelerator and an epoxy resin are mixed, curing starts, so that both are mixed immediately before use.

The present invention is not limited to the above-mentioned tar epoxy paint, but is disclosed in JP-A-56-1107.
No. 63, an epoxy resin, a bituminous substance,
Glass flakes, those comprising a filler and a solvent, epoxy resins described in JP-A-56-4662,
Tar epoxy paints usually used as anticorrosive paints, such as those comprising an epoxy resin curing agent and a coal tar based bituminous substance or a non-coal tar based polymeric substance and a solvent, can be used.

The fluorescent paint which is invisible under visible light but emits by ultraviolet light used in the present invention is a dye which is activated by ultraviolet light to emit light. The fluorescent paint used in the present invention may be in the form of a powder as long as it can be dissolved in the tar epoxy paint, and can dissolve a dye such as a solvent (methyl ethyl ketone, methyl alcohol, ethyl alcohol, toluene, xylene, etc.). ) May be dissolved. Furthermore, even if it is insoluble in tar epoxy paint or pigment-like insoluble in solvent, as long as the hiding power is weak, the content of the fluorescent dye after coating film drying is not visually recognized and there is no problem. .

Examples of the fluorescent paint include Lumogen L Blue (diethyl 2,5-dihydroxyterephthalate) having the chemical formula shown in Table 1 and Lu having the chemical formula shown in Table 1
mogen Water Blue (dixanthene), Lumogen L Yellow
(9,10-dianilinoanthracene), Lumogen Yellow Orange (salicylaldazine) having the chemical formula shown in Table 1, Lumogen Bright Yellow (2-oxynaphthoaldazine), Lumogen Br having the chemical formula shown in Table 1
illiant Green [1,4-bis (β-cyano-) obtained by condensation of terephthalaldehyde and ethyl cyanoacetate
β-carbethoxyvinyl) benzene], Lumogen L Red Orange (anthrapyridine derivative) having the chemical formula shown in Table 1, urea formaldehyde; CI Fluorescen
t Brightening Agent 14, 24, 30, 32, 52,
54, 69, 79, 84, 85, 86, 87, 90, 1
04, 112, 113, 114, 119, 121, 13
4, 135, 152, 166, 167, 168, 16
9, 191, 192, 201, 204, 214, 21
6, 217, 218, 223, 226, 229, 23
4,236,239,240,242,257,26
0, 271, 290, 310, 311, 312, 31
3, 314, 315; CI Basic Red 1, 1-1;
CI Basic Violet 10, 11: 1; CI Basic Yel
low 35, 40, 95; CI Basic Blue 7; P-
Quarterphenyl; P-terphenyl; 2,5-diphenyloxazole; 2- (1-naphthyl) -5-
Phenyloxazole; 2-phenyl-5- (4-biphenyl) -1,3,4-oxadiazole; 3-phenyl-7- (1,2-2H-naphthotriazolyl)-
Coumarin; 3,7-bis (diethylamino) phenoxazonium nitrate; 2,5-bis [5'-t-butylbenzoxazolyl (2)] thiophene; europium-thenoyltrifluoroacetone chelate; -Ropium-benzoyltrifluoroacetone chelate, and the like, but is not limited thereto.

[0015]

[Table 1]

The tar epoxy coating composition of the present invention preferably contains 0.1 to 20 parts by weight of the above fluorescent dye based on 100 parts by weight of the above tar epoxy coating.
When the content of the fluorescent dye is less than 0.1 part by weight, the amount of emitted light is small even when irradiated with ultraviolet light, and it tends to be difficult to identify the coating film. Conversely, if the amount exceeds 20 parts by weight, the repaired portion tends to be discolored after the coating film is dried, and the appearance tends to be impaired.

The tar epoxy coating composition of the present invention may contain additives such as pigments, resins, etc. which are commonly added to coatings. Furthermore, in the present invention, in order to uniformly dissolve or disperse the fluorescent dye in the tar epoxy paint, a solvent or a resin that is usually used in paint production, a resin,
You may use together a dispersing agent, an additive, etc.

The method for visually recognizing a coating film according to the present invention is a method for applying a tar epoxy coating composition containing a fluorescent dye, which is invisible under visible light but emits by ultraviolet light, on a substrate to be coated. This is a method of irradiating the coating film with ultraviolet light to visually recognize the coating film by emitting light, whereby the portion formed of the tar epoxy coating composition containing a fluorescent dye, that is, the repaired portion and the unrepaired portion Can be identified.

The objects to be coated with the tar epoxy coating composition of the present invention include cast iron frames in ductile segments and tunnels of subways, plumbing facilities such as gas and water pipes, and fluid raw materials in industrial areas. Examples of such pipes include transportation pipes, steel pipe piles for building foundation work, and iron pipes or steel pipes.

[0020]

EXAMPLES The present invention will be described below more specifically based on examples and comparative examples. Example 1, Example 2, and Comparative Example 1 Preparation of Composition A Tar epoxy paint “KUBOTA COAT # 1001ZEX-
12 "(trade name, manufactured by Dai Nippon Paint Co., Ltd.) and 15 parts by weight of 2,5-bis [5'-t-butylbenzoxazolyl (2)] thiophene which is a fluorescent dye. Composition A was prepared.

Preparation of Composition B Tar epoxy paint "KUBOTA COAT # 1001ZEX-
Composition B was prepared by mixing 100 parts by weight of No. 12 and 13 parts by weight of urea formaldehyde as a fluorescent dye. Preparation of Composition C Tar epoxy paint “KUBOTA COAT # 1001ZEX-
12 "alone was used as composition C.

Blast processing of three iron plates (ISO SI
S2 _^1/2 near white metal) and, after preheated at 60 ° C., the composition C to a half of one surface of each steel plate was spray-coated, the above compositions as shown in Table 2 in the other half A, B or C was spray-coated and air-dried, and the following evaluation was performed on those coating films. The results were as shown in Table 2.

<Appearance of coating film> ○ indicates that it is impossible to visually discriminate under visible light the coating film surface of each half of each painted iron plate, and indicates that it can be visually discriminated under visible light. Is indicated by x. <Luminescence> National UV lamp for excitation
Using BP-642, the distance between the coating film and the ultraviolet lamp was set to 5 cm, and the case where the emission intensity level of the sample at the time of excitation was identifiable by visual judgment was evaluated as 、, and the case where it was not identifiable by visual judgment was evaluated as ×.

[0024]

As is apparent from Table 2, a coating film obtained using the tar epoxy coating composition of the present invention containing a fluorescent dye which is invisible under visible light but emits by ultraviolet light, and a fluorescent dye The coating obtained using the tar epoxy coating composition containing no difference is not recognized under visible light, but a clear difference is recognized under irradiation of ultraviolet light, the tar epoxy coating composition of the present invention The utility is obvious.

[0026]

By using the tar epoxy paint composition of the present invention and adopting the method for visually confirming the coating film of the present invention, it is possible to perform repair work for a portion where the tar epoxy paint is coated for a long time or a long time. Even if it lasts for days, or if it is partially repaired every few years,
It is possible to identify the location repaired the previous day or years ago, and thus identify the boundary between the repaired location and the unrepaired location.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takayuki Sato 6-34-510 Gokencho, Nishinasuno-cho, Nasu-gun, Tochigi Prefecture 510

Claims (2)

[Claims] 1. A tar epoxy coating composition comprising a fluorescent dye which is invisible under visible light but emits light by ultraviolet light. 2. A method for visually recognizing a coating film, comprising irradiating the coating film formed by applying the tar epoxy coating composition according to claim 1 with ultraviolet light to cause the coating film to emit light.