JPH0428531A - Prepreg coating method using double-layer primer - Google Patents

Abstract

PURPOSE:To obtain a corrosion-proof coating layer having excellent shock resistance and toughness by successively coating the surface of a steel material with polyamine having reactive curing property at normal temperature and an epoxy resin composition using polythiol as a curing agent and fast sticking and curing a permanently deformable prepreg coating layer. CONSTITUTION:The surface of a steel material is coated with an epoxy resin primer composition employing polyamine as a curing agent and having reactive curing property at normal temperature, and an epoxy resin primer composition using polythiol as the curing agent and having reactive curing property at normal temperature is applied and cured, thus forming an adhesive double-layer primer layer. A fiber working reinforcing material is impregnated with a liquid resin composition having reactive curing property at normal temperature on the primer layer, a prepreg coating layer cured up to a solid shape in which permanently deformable plasticity appears is cured is laminated, and both layers are fast stuck and cured completely. The primer layer must be cured until initial tackiness with the prepreg coating layer is brought to 0.5g/cm or more. Accordingly, a double-layer primer layer is formed, thus covering both defects.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a prepreg coating method for applying a heavy corrosion protection coating to a wet/dry alternating section of a marine steel structure, etc., and a prepreg coating material used therein.

[Prior art and problems] Conventionally, tar epoxy resin paints, thick film polyurethane paints, thick film epoxy resin paints, etc. have been used as anti-corrosion coatings for submerged parts, dry/wet alternating parts, splash parts, etc. of marine steel structures. ing.

However, although tar epoxy resin paints have relatively good corrosion resistance, they have extremely poor impact resistance, and as a result, the coating film is easily damaged and the corrosion resistance is likely to deteriorate. In addition, the strength and hardness of the coating film is low, making it difficult to break during transportation or installation of steel structures, and tar is undesirable because it has hygienic problems such as odor and carcinogenicity due to its composition.

Further, thick film polyurethane paints are inferior in terms of corrosion resistance and painting workability, and also have the problem of lacking M roughness in terms of adhesion.

Further, thick film epoxy resin paints have problems in workability, such as poor coating workability and impact resistance, and difficulty in obtaining a uniform thick film.

[Means for Solving the Problems] In order to solve the problems found in conventional anti-corrosion coatings for marine steel structures, the inventors of the present invention have conducted intensive studies and have developed a method using a specific prepreg coating material. We have discovered that these problems can be solved by using a new coating method, and have completed the present invention.

Thus, according to the present invention, (i) an epoxy resin primer composition that is reactively curable at room temperature and uses a polyamine as a hardening agent is completely coated on the surface of the steel material, and then an epoxy resin primer composition that is reactively curable at room temperature and uses polythiol as a hardener is coated on the surface of the steel material; A resin-based primer composition is applied, and the initial adhesive strength with the upper prepreg coating layer shown below is 0. ! M/alI
(ii) on the adhesive primer layer, impregnating the fiber processing reinforcing material with a liquid resin composition that is reactively curable at room temperature; A prepreg coating layer that has been cured to a solid state exhibiting permanently deformable plasticity is bonded together, and then (iii) both the adhesive multilayer primer layer and the prepreg coating layer are completely bonded and cured. A featured prepreg coating method is provided.

The present invention will be specifically explained below.

The epoxy resin primer composition, which is reactively curable at room temperature and uses polyamine as a curing agent, used to form the second layer of the adhesive multilayer primer layer in the method of the present invention is a conventionally known two-component engineered epoxy resin primer composition. A composition is used. Epoxy resins include bisphenol A type, bisphenol F type, bisphenol AD type, novolac type, etc., and curing agents include, for example, modified aliphatic amines,
Conventionally known modified amine curing agents such as modified aromatic amines are used.

The epoxy resin primer composition, which is reactively curable at room temperature and uses polythiol as a curing agent, used to form the second layer of the adhesive multilayer primer layer in the method of the present invention is a conventionally known two-component engineered poxy resin. based compositions are used. As the epoxy resin, all those used in the M1 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 thiol groups, 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 is diisocyanate. Conventionally known curing agents can be used, such as a curing agent added to a polyol via a curing agent, and a curing agent added to a polyepoxide with curing hydrogen.

The reason for using multiple layers of adhesive primers is that epoxy resin primers using polyamine hardeners have excellent adhesion and corrosion resistance to steel sheet substrates, but they do not have an effective initial bond with the prepreg coating layer during the drying and curing process. The period during which adhesive strength is exerted is short, and there is no margin for timing when applying the prepreg. On the other hand, an epoxy resin-based primer using a polythiol curing agent has a large initial adhesive strength with the prepreg coating layer during the drying and curing process, and it is also possible to attach the prepreg to a curved steel material with a small radius of curvature. Since the initial adhesion force is maintained for a long time as described above, there are few restrictions on the timing of attaching the prepreg, but on the other hand, the adhesion to the steel plate base and corrosion resistance are somewhat inferior.

In the present invention, by combining the two types of primer compositions described above to form a multilayer primer layer, the drawbacks of both can be covered and their characteristics can be utilized.

The above-mentioned adhesive multilayer primer composition is sequentially applied to the surface of the steel material, generally in a dry film thickness in the range of 10 to 100 μm, and has an initial adhesive strength of 0.5j9/am or more with the prepreg coating layer pasted as an upper layer. to form an adhesive primer layer. Here, if the curing state of the primer layer deviates from the above conditions, that is, if the drying and curing of the primer layer does not proceed much or has proceeded too much, the initial adhesion with the prepreg coating layer will be insufficient, and the adhesion will be difficult. Problems include misalignment during work, slippage of the prepreg coating layer on vertical surfaces, and peeling of the prepreg coating layer due to rebound on curved surfaces. The adhesive multilayer primer composition has a long adhesive time during the application → drying → curing process,
It reacts and hardens at room temperature, and has excellent adhesion to the steel base and the upper prepreg coating layer, as well as excellent corrosion resistance.

Further, if it is necessary to further improve functions such as strength and corrosion resistance of the primer layer, this can be achieved by dispersing various known fillers such as flake pigments and antirust pigments in the primer composition.

Next, the heavy-duty anti-corrosion prepreg coating material, which is bonded to the adhesive primer layer described above to form a prepreg coating layer, is applied to a two-dimensionally expanded fiber processed reinforcement material (hereinafter referred to as "planar reinforcement material") at room temperature. It is impregnated with a reaction-curable liquid resin composition to a constant thickness in the range of 0.5 to 5 g, and is cured until it becomes a solid state in which a permanently deformable plasticizer is expressed. .

The planar reinforcing material helps form the reaction-curable liquid resin composition into a uniform film thickness, prevents damage to the coating film due to impact from objects floating in the ocean, reinforces the coating film, and improves bending resistance. fulfill one's role.

Conventionally known organic fibers and inorganic fibers are used as the material for the planar reinforcing material. Examples of organic fibers include natural fibers such as cotton, hemp, wool, and rope; synthetic fibers such as acetate, acrylic, polyether, polyurethane, polyolefin, polyamide, and polyimide; examples of inorganic fibers include glass, Examples include fibers such as carbon, boron, alumina, silicon carbide, silicon nitride, and stainless steel. These are mesh-like molded products such as woven fabrics, non-woven fabrics, paper, and mats made from long or short fibers, porous films, and
Used in the form of sheets, etc.

The reaction-curable liquid resin composition impregnated into the planar reinforcing material is
The main ingredients are two-component epoxy, polyurethane, unsaturated polystyl resin, etc., which react and harden at room temperature.

As the two-component poxy resin composition, bisphenol Aff, bisphenol F type, bisphenol AD,
Modified epoxy resins such as novolac type such as phenol and cresol, acrylate modified, urethane modified, and polybutadiene rubber modified can be used, and these have low viscosity, adhesion to the substrate, corrosion resistance, impact resistance, flammability, etc. It is characterized by excellent performance.

These epoxy resins are cured by reaction with an amine-based curing agent that has characteristics such as impact resistance, sinterability, and water resistance.
For example, various known amine 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 a polyol component that is solvent-free and has excellent impact resistance, stress relaxation properties, abrasion resistance, weather resistance, water resistance, etc., such as alkoxylated bisphenol A.
Using castor oil fatty acid ester, epoxy-modified polyol, etc., monomers such as tolylene diisocyanate, diphenylmethane diisocyanate, metaxylene diisocyanate, etc. as incyanate curing agent components,
or biuret, allophanate, incyanuret,
It is made by blending a multimer such as urethane adduct.

The unsaturated polyester resin composition contains an unsaturated dibasic acid such as (anhydrous) maleic acid, fumaric acid, and itaconic acid,
Polyester, acrylic acid, and methacrylic acid synthesized by mainly containing polyhydric alcohols such as ethylene glycol, diethylene glycol, glycerin, and propylene glycol, and partially blending 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, corrosion resistance, stress relaxation properties, etc. of the above-mentioned reaction-curable liquid resin composition, various known fillers may be added as necessary.

For example, fine powder fillers include modified polyethylene fine powder, crosslinked phenol resin fine powder, polyphenylene sulfide fine powder, phenoxy resin fine powder, etc.; balloon fillers include glass balloons, shirasu balloons, plastic balloons, etc. Examples of the flake filler include titanium flakes, aluminum flakes, stainless steel flakes, chrome flakes, and mica flakes. Examples of extender pigments include tartar, mica, tancal, barida, and silica.

The above reaction-curable liquid resin composition is impregnated into the planar reinforcing material, but a low viscosity is desirable for impregnation workability, and a small amount of solvent is desirable from the viewpoint of ensuring film thickness and safety and hygiene. . Furthermore, it is also possible to use a low-viscosity reactive or non-reactive diluent, if necessary, such as when working at low temperatures.

Examples of impregnation methods include the following methods.

(1) The impregnated resin composition is cast to a certain thickness, and the planar reinforcing material is sunk thereon.

(2) The planar reinforcing material is immersed in a container filled with the impregnated resin composition, and pulled up while scraping off the excess resin composition.

(3) The planar reinforcing material is sandwiched between two pieces of release paper, the impregnated resin composition is filled between them, and the material is passed through two rolls having a certain clearance while being squeezed.

As described above, the planar reinforcing material is impregnated with the impregnated resin composition, and is reacted and cured at room temperature until it becomes a solid state that exhibits plasticity capable of being permanently deformed, thereby producing a prepreg covering material. This prepreg covering material is pasted on the adhesive primer layer, but the cured state of the prepreg covering material needs to be in the above-described state. If this is not the case, for example, if it is a liquid that has not progressed much in curing, it will be very difficult to paste it, and moreover, it will be more likely that distortion will remain due to volatilization of the solvent and hardening of the resin. The durability of the coating system cannot be expected, and conversely, if hardening progresses too much, the prepreg loses its plasticity, making it difficult to coat steel structures other than planar shapes.

[Functions and Effects 1] In the present invention, since the adhesive primer layer is made into multiple layers, the prepreg can be attached with ease, and has excellent adhesion and anticorrosion properties.

It becomes a primer layer. A prepreg coating material is laminated on top of the prepreg coating material and the completely cured film obtained by completely adhering and curing can be used as a heavy corrosion protection coating layer, and its functions are: (i) Impact resistance and toughness (ii) Excellent barrier properties against steel corrosion factors (02, H, O, CQ, etc.) (iii) and adhesion to the lower layer (primer), etc.
It has the effect of protecting the lower anticorrosion layer (primer layer) from the environment and (iv) having excellent long-term durability as described in (i) to (iii) above.

[Example] Hereinafter, the present invention will be specifically explained based on an example. "Parts" in the examples mean "parts by weight."

Examples 1 to 2 The coating primer composition shown in Table 1 was applied to the surface of 30OA steel to a thickness of 25 μITl (dry film thickness), dried at room temperature for various times, and then coated with the coating primer composition shown in Table 1. A prepreg covering material having a thickness of 1.5 mm as shown in Figure 1 was bonded and completely cured.

The adhesion state 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 Each primer composition shown in Table 1 was used as an adhesive primer in a single layer.

Claims (1)

[Claims] 1. (i) Apply an epoxy resin primer composition that is reactively curable at room temperature using polyamine as a curing agent to the surface of the steel material, and then apply an epoxy resin primer composition that is reactively curable at room temperature and uses polythiol as a curing agent. Apply the resin primer composition and have an initial adhesive strength of 0.5 g/cm with the upper prepreg coating layer below.
(ii) on the adhesive multilayer primer layer, a liquid resin composition that is reactively curable at room temperature is impregnated into the fiber processing reinforcing material; , bonding a prepreg coating layer that has been cured to a solid state that exhibits permanently deformable plasticity, and then (iii) completely adhering and curing both the adhesive multilayer primer layer and the prepreg coating layer. A prepreg coating method characterized by: