JPH0776278B2 - Prepreg coating method using multilayer primer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a prepreg coating method for applying a heavy anticorrosion coating to a wet and dry alternating part of a marine steel structure and the like, and a prepreg coating material used therefor.

[Conventional technology and problems] Conventionally, tar epoxy resin paints, thick film polyurethane paints, thick film epoxy resin paints, etc. have been used as anticorrosion coatings for submerged parts, wet and dry alternating parts, and splash parts of marine steel structures. ing.

However, although the tar epoxy resin coating has a relatively good anticorrosion property, it is extremely inferior in impact resistance, and as a result, the coating film is easily damaged and the anticorrosion property is likely to be deteriorated. Further, the strength and hardness of the coating film are low, and the steel structure is liable to be broken during transportation or installation of the steel structure, and tar has odor, carcinogenicity, and other sanitary problems from the viewpoint of composition, which is not preferable.

Further, the thick-film polyurethane coating is inferior in terms of anticorrosion property and coating workability, and also has a problem that it lacks reliability in adhesion.

Further, the thick film epoxy resin coating composition has the problems of poor workability and impact resistance, and it is difficult to obtain a uniform thick film.

[Means for Solving Problems] The inventors of the present invention have conducted extensive studies to solve the problems found in conventional anticorrosion coatings for marine steel structures, and as a result, have developed a novel prepreg coating material using a specific prepreg coating material. It was found that these problems can be solved by using various coating methods, and the present invention has been completed.

Thus, according to the present invention, (i) an epoxy resin primer composition having a polyamine as a curing agent and curable at room temperature is applied to the surface of a steel material, and then an epoxy resin having a polythiol as a curing agent and curable at room temperature is used. A resin-based primer composition is applied and cured until the initial adhesive force with the following prepreg coating layer as an upper layer becomes 0.5 g / cm or more to form an adhesive multilayer primer layer, (ii) the adhesive primer On the layer, a prepreg coating layer obtained by impregnating a fiber processing reinforcement material with a liquid resin composition that is reactively curable at room temperature and curing it until it becomes a solid state that exhibits permanent deformable plasticity is attached, and then ( iii) A prepreg coating method is provided, which comprises completely adhering and curing both the adhesive multilayer primer layer and the prepreg coating layer.

Hereinafter, the present invention will be specifically described.

The epoxy resin-based primer composition, which is used as a curing agent for the first layer of the adhesive multilayer primer layer in the method of the present invention and is curable at room temperature, is a conventionally known two-component epoxy resin-based primer composition. A composition is used. Examples of the epoxy resin include bisphenol A type, bisphenol F type, bisphenol AD type and novolak type, and examples of the curing agent include modified aliphatic amine,
A conventionally known modified amine-based curing agent such as a modified aromatic amine is used.

The epoxy resin-based primer composition, which is used as a curing agent for the second layer of the adhesive multilayer primer layer in the method of the present invention and is curable at room temperature, is a conventionally known two-component epoxy resin-based primer composition. A composition is used. As the epoxy resin, any of those used for the first layer of the multilayer primer layer can be used. As the curing agent, a polythiol-based curing agent having an average of 2 or more, preferably 2 to 3 thiol groups per molecule is used. For example, a curing agent having thiol groups at both ends of polyalkylene oxide, thioglycol and diisocyanate are used. Conventionally known agents such as a curing agent added to a polyol via a curing agent and a curing agent added to a polyepoxide with curing hydrogen are used.

The reason why the adhesive primer has multiple layers is that the epoxy resin-based primer that uses a polyamine curing agent has excellent adhesion to the steel plate substrate and corrosion resistance, but it is effective in the initial stage with the prepreg coating layer during the dry curing process. The period of exhibiting adhesion is short, and there is no margin in the timing of pasting the prepreg. On the other hand, an epoxy resin-based primer using a polythiol curing agent has a large initial adhesion to the prepreg coating layer during the drying and curing process and can be attached to a curved steel material having a small radius of curvature. As described above, since the initial adhesion is maintained for a long time, there are few restrictions on the timing of attaching the prepreg, but on the other hand, the adhesion to the steel sheet substrate and the corrosion resistance are slightly inferior.

In the present invention, by combining the above-mentioned two types of primer compositions to form a multilayer primer layer, the drawbacks of both are covered and the characteristics thereof are utilized.

The adhesive multilayer primer composition is generally applied to the surface of the steel material in order in a dry film thickness range of 10 to 100 μm, and the initial adhesive strength with the prepreg coating layer to be applied as the upper layer is 0.
The adhesive primer layer is formed by reacting and curing at room temperature until it becomes 5g / cm or more. Here, if the cured state of the primer layer deviates from the above conditions, that is, if the primer layer does not dry or cure too much, or if it has progressed too much, the initial adhesion to the prepreg coating layer is insufficient, and sticking There are problems such as displacement during work, slipping of the prepreg coating layer on a vertical surface, and peeling of the prepreg coating layer on a curved surface due to rebound. The adhesive multilayer primer composition is applied →
It has the characteristics that it takes a long time to exhibit tackiness in the process of drying and curing, reacts and cures at room temperature, and has excellent adhesion to the steel base material and the upper prepreg coating layer and excellent corrosion resistance.

When it is necessary to further improve the strength and anticorrosion properties of the primer layer, it can be achieved by dispersing various known fillers such as flake pigments and rust preventive pigments in the primer composition.

Next, the heavy-duty anti-corrosion prepreg coating material that is bonded to the above-mentioned adhesive primer layer to form a prepreg coating layer is a fiber processing reinforcing material having a two-dimensional spread (hereinafter,
A "surface reinforcement" is impregnated with a liquid reaction curable liquid resin composition at room temperature to a certain thickness within a range of 0.5 to 5 mm to form a solid form that exhibits a permanently deformable plasticizer. It is a cured product.

The above-mentioned sheet-like reinforcing material has a role of helping the uniform film thickness moldability of the reaction curable liquid resin composition, preventing the coating film from being damaged by the impact of drifting matter in the ocean, and reinforcing the coating film and improving the bending resistance. Complete

As the material of the sheet-like reinforcing material, conventionally known organic fibers and inorganic fibers are used. Examples of the organic fibers include natural fibers such as cotton, hemp, wool, and silk, and synthetic fibers such as acetate, acrylic, polyether, polyurethane, polyolefin, polyamide, and polyimide, and examples of the inorganic fibers include glass, carbon·
Examples thereof include fibers such as boron, alumina, silicon carbide, silicon nitride, and stainless steel. These are used in the form of mesh-shaped molded products such as woven fabrics, non-woven fabrics, papers, mats and the like processed from long fibers or short fibers, and porous films and sheets.

The reaction curable liquid resin composition impregnated into the planar reinforcing material,
The main component is a two-pack type epoxy, polyurethane, an unsaturated polyester resin, etc., which is reactively cured at room temperature.

As the two-pack type epoxy resin composition, bisphenol A type, bisphenol F type, bisphenol AD type, novolac type such as phenol and cresol, modified epoxy resin such as acrylate modified, urethane modified, and polybutadiene rubber modified can be used. Has a low viscosity, excellent adhesion to the substrate, anticorrosion, impact resistance, burnability, and other characteristics.

These epoxy resins are cured by reaction with an amine-based curing agent having characteristics such as impact resistance, burnability, and water resistance.
For example, various known amine-based curing agents such as modified aliphatic amines, modified aromatic amines, heterocyclic diamines, polyamine Mannich derivatives, and aliphatic polyamine Michael adducts are used.

The polyurethane resin composition is solvent-free as a polyol component and is excellent in impact resistance, stress relaxation property, abrasion resistance, weather resistance, water resistance and the like, for example, alkoxylated bisphenol A.
Castor oil fatty acid ester, epoxy modified polyol, etc. are used, and as the isocyanate-based curing agent component, monomers such as tolylene diisocyanate, diphenylmethane diisocyanate, and meta-xylene diisocyanate,
Alternatively, it is a mixture of multimers such as biuret, allophanate, isocyanurate, and urethane adduct.

The unsaturated polyester-based resin composition includes an unsaturated dibasic acid such as (anhydrous) maleic acid, fumaric acid, and itaconic acid,
Polyester or acrylic acid or methacrylic acid mainly composed of polyhydric alcohols such as ethylene glycol, diethylene glycol, glycerin and propylene glycol, and partially mixed with saturated polybasic acids such as phthalic anhydride, isophthalic acid and adipic acid. Unsaturated acids such as acids,
Vinyl ester resin made by reacting epoxy resin,
It is dissolved in vinyl monomers such as styrene, vinyltoluene, and acrylic ester.

In order to further improve the impact resistance, abrasion resistance, anticorrosion property, stress relaxation property and the like of the above-mentioned reaction curable liquid resin composition, various known fillers are blended as necessary.

For example, as the fine powder filler, modified polyethylene fine powder, crosslinked phenol resin fine powder, polyphenylene sulfide fine powder, phenoxy resin fine powder, and the like, and as balloon filler, glass balloon, shirasu balloon, plastic balloon, etc. Examples of the filler include titanium flakes, aluminum flakes, stainless flakes, chrome flakes, and mica flakes. Examples of extender pigments include talc, mica, tankar, barita, and silica.

The above-mentioned reaction curable liquid resin composition is impregnated into the sheet-like reinforcing material, but a low viscosity is desirable for impregnating workability, and it is desirable that the amount of solvent is small from the viewpoint of securing the film thickness and safety and hygiene. . Further, it is also possible to use a low-viscosity reactive or non-reactive diluent as required during low temperature operation.

Examples of the impregnation method include the following methods.

(1) The impregnated resin composition is cast to a certain thickness, and the sheet-like reinforcing material is sunk from above.

(2) The sheet-like reinforcing material is immersed in a container filled with the impregnated resin composition, and an excess resin composition is scraped off and pulled up.

(3) The sheet-like reinforcing material is sandwiched between two pieces of release paper, the impregnating resin composition is filled therebetween, and two rolls having a certain clearance are passed through while squeezing.

As described above, the sheet-like reinforcing material is impregnated with the impregnated resin composition, and the mixture is reacted and cured at room temperature, and then cured until it becomes a solid that exhibits permanent deformable plasticity to prepare a prepreg coating material. The prepreg coating material is attached to the adhesive primer layer, but the prepreg coating material needs to be in the above-described cured state. If this is not the case, for example, when the liquid is not cured so much, the attaching work is very difficult, and further, the occurrence of distortion due to the volatilization of the solvent or the curing of the resin after attaching becomes large, and the coating system The durability cannot be expected, and conversely, if the hardening proceeds too much, the plasticity of the prepreg is lost and it becomes difficult to cover the steel structure other than the plan shape.

[Operations and Effects] In the present invention, the adhesive primer layer is formed of a plurality of layers, so that the prepreg can be attached with sufficient margin, and the adhesive layer has excellent adhesion and anticorrosion properties. A completely cured film obtained by laminating a prepreg coating material on it and completely curing it by adhesion can be used as a heavy anticorrosion coating layer. Its functions are: (i) impact resistance and toughness (ii) Barrier of steel corrosion factors (O ₂ , H ₂ O, Cl, etc.) (iii) Excellent adhesion to the lower layer (primer), and protects the lower corrosion-prevention layer (primer layer) from the environment ( iv) There is an effect that the long-term durability of the above (i) to (iii) is also excellent.

[Examples] Hereinafter, the present invention will be specifically described based on Examples. "Parts" in the examples means "parts by weight".

Examples 1 and 2 The coating primer composition shown in Table 1 was applied on the surface of a 300A steel material so as to have a thickness of 25 µm (dry film thickness), dried at room temperature for various times, and then on Table 1 The prepreg coating material having a thickness of 1.5 mm shown in (3) was attached and completely cured. The state of adhesion and corrosion resistance of the thus obtained completely cured film to the steel pipe were evaluated, and the results shown in Table 1 were obtained.

Comparative Examples 1 to 3 As the adhesive primer, each primer composition shown in Table 1 was used in a single layer.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technology display location B29L 9:00 (72) Inventor Takaaki Uedera 1-5-26 Motokakasaka, Minato-ku, Tokyo Hojin Japan Paint Industry Association (72) Inventor Tahito Nishimura 1-5-26 Moto-Akasaka, Minato-ku, Tokyo Hojin Nippon Paint Industry Association (72) Inventor Shunichi Sano 1-chome Moto Akasaka, Minato-ku, Tokyo No. 5 26 Japan Society of Painters (72) Inventor Toru Saiga 603-2 221, Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa

Claims (1)

[Claims] 1. An (i) epoxy resin primer composition having a polyamine as a curing agent and a reaction curable epoxy resin primer composition at room temperature, and then a polythiol as a curing agent which is a reaction curable epoxy resin primer composition at a room temperature. The initial adhesive strength with the following prepreg coating layer, which is the upper layer, is 0.5g / c.
The adhesive multi-layer primer layer is formed by curing until it becomes m or more, and (ii) the reaction-curable liquid resin composition at room temperature is impregnated into the fiber processing reinforcing material on the adhesive multi-layer primer layer. hand,
A prepreg coating layer that has been cured until it becomes a solid that exhibits permanent deformable plasticity is attached, and then (iii) complete adhesion and curing of both the adhesive multilayer primer layer and the prepreg coating layer. A characteristic prepreg coating method.