JPS6364739A - Colored polyurethane elastomer coated heavy-duty corrosion-resistant steel material - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] <Industrial Application Fields> The present invention is applicable to port and river construction, as well as forest management and maintenance.
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+aanor@::Relates to colored polyurethane elastomer-coated heavy corrosion-resistant steel materials with excellent corrosion resistance and corrosion resistance, which are used for bale sheet piles, steel pipe piles, H-section steel, etc.

<Conventional technology and its problems> Most of the conventional heavy corrosion-resistant steel materials such as steel sheet piles, steel pipe sheet piles, and H-beams are black, which is incongruous with the surrounding environment of the structure, and coloring is also a problem from a safety perspective. It is becoming demanded. Coloring of other structures, especially development of environmentally harmonious colors, is required. Examples of this include power transmission towers, lighting poles, and lighting towers, where galvanized coatings are increasingly being painted.

By the way, as a colored heavy corrosion-resistant steel material using conventional technology,
There is Japanese Patent Application Laid-Open No. 60-92521, in which colored polyolefin sheets are bonded together using an adhesive, which is similar to the technique for bonding polyethylene sheets (black). However, it is difficult to adhere colored heavy corrosion-resistant steel materials using this method to complex shapes. Furthermore, since black additives such as carbon black are used, the range of coloring is limited. Furthermore, there was a problem that reducing the addition of carbon black was likely to cause a drop in performance compared to the previous one.

In addition, in recent years, heavy-duty anti-corrosion coated steel materials in which steel materials are coated with polyurethane elastomers have been disclosed, for example, in Japanese Patent Laid-Open No. 61-26675. However, these polyurethane elastomer coating materials for heavy corrosion protection require mechanical strength, so they are made from aromatic diisocyanates and polyols, and when exposed to sunlight, polyurethane gradually turns yellow, deteriorates in physical properties, and becomes brittle. cause a change. As a result, reduction in gloss and whitening of the paint film are observed, and cracks appear on the paint film surface. This includes, for example, MDI (diphenylmethane-4), which is an aromatic diisocyanate in the polyurethane main chain.
, 4'-diisocyanate) and a polyol.

- Compositions obtained by reacting universal aliphatic or alicyclic polyisocyanates with polyols do not discolor and have excellent weather resistance because aliphatic urethanes cannot form quinoid structures that cause yellowing. However, (1) the reaction rate between the aliphatic or alicyclic polyisocyanate and the polyol is slow and it is difficult to obtain a 17-layer coating such as a heavy anticorrosion coating; (2) the mechanical properties of the resulting polyurethane elastomer composition. (3) aliphatic or alicyclic The adhesion of the polyurethane elastomer composition obtained from the group polyisocyanate to the steel material and the water resistance of the coated steel material are inferior to those of the polyurethane elastomer composition obtained from the aromatic polyisocyanate; (4) aliphatic or alicyclic polyisocyanate; Because group polyisocyanates are expensive, they are not suitable for heavy-duty corrosion protection applications.

<Object of the Invention> The object of the present invention was made in view of the above-mentioned circumstances, and provides a heavy corrosion-resistant steel material coated with a colored polyurethane elastomer that solves the above-mentioned problems and has excellent weather resistance, corrosion resistance, and good mechanical properties. This is what we intend to provide.

<Structure of the Invention> The present invention provides the following methods: a. aromatic polyisocyanate and aliphatic and/or alicyclic polyisocyanate in a weight ratio (95 to 5):
It is coated with a polyurethane elastomer layer containing a polyisocyanate mixed in a ratio of (5 to 95), b) a polyol, a C0 colored pigment, and a d9 metal-based fatty acid salt of group Ⅰ of the periodic table. To provide a heavy corrosion protection material coated with a colored polyurethane elastomer.

Hereinafter, the colored polyurethane elastomer-coated heavy duty corrosion-resistant steel material of the present invention will be explained in more detail.

Steel materials lined in the present invention include structural steel,
Steel pipe piles made of high-tensile copper, weather-resistant steel, anti-magnetic P# bamboo steel, etc.
Examples include steel pipe sheet piles, steel sheet piles, and H-shaped piles. After descaling and cleaning the anti-corrosion surface of the steel material by blasting such as shot blasting, grid blasting or sandblasting, or by pickling with sulfuric acid or hydrochloric acid,
A colored polyurethane elastomer is coated via a chemical conversion treatment layer, an adhesive layer, etc. to obtain a heavy corrosion-resistant steel material coated with a colored polyurethane elastomer. In the present invention, in order to improve the adhesion between the polyurethane elastomer layer and the surface of the steel material, it is preferable to use a chemical conversion treatment layer, a layer of organic resin brimer as an adhesive, or a multilayer system using a combination of these.

The chemical conversion treatment used in this invention is preferably a phosphate treatment, a chromate treatment, or a combination thereof. Examples of the phosphate treatment include iron phosphate, zinc phosphate, zinc calcium phosphate, and the like. The amount of iron phosphate applied is 0.2 to 1.
．． 0 g/ln2, zinc phosphate and zinc calcium phosphate preferably range from 1.0 to 3.0 g/m2. If the amount exceeds these amounts, the film will be brittle and the adhesion and impact resistance of the coating will be reduced. Also, if it is less than these amounts,
Water resistance decreases.

Reactive chromate, electrolytic chromate, and coated chromate can be used for chromate treatment, but coated chromate is superior in terms of workability. As for the amount of coating, the total amount of chromium is 20mg/rr? ~5“001IIg/
If the amount of chromium is less than 20 mg/rn', there is no effect on water resistance, and if it exceeds 500 mg/rf, the impact resistance of the coating will decrease.

In the case of paint-on type chromate, apply the treatment solution to the steel material by applying it, spraying it, or splashing it and drying it. The preferred method for drying the chromate-coated steel is thermal drying such as electric furnace high-frequency induction heating. The heating temperature is in the range of 60 to 300°C, preferably 80 to 120°C. The coating type chromate treatment liquid preferably has an Or''/Cr'+ of 115 to 2/3, and the binder is an inorganic polymer such as silka sol, alumina sol, or alkyl silicate, or polyvinyl alcohol, polyacrylic acid, or polyacrylic acid ester. Additives such as water-soluble polymers may be added to the chromic acid aqueous solution.

In the present invention, although phosphate treatment and chromic acid treatment alone provide excellent water resistance, a combined treatment of phosphate treatment followed by chromic acid treatment may be performed.

Further, as described above, it is preferable to use an organic resin brimer as the adhesive, and the organic resin brimer is the colored polyurethane elastomer coating material of the present invention, which is made of an epoxy resin, a phenol resin, a phenoxy resin, or a urethane resin, alone or in combination. A material with excellent adhesion to the surface is used. When applying these organic resin brimers to steel materials, apply 10 to 10 ml of organic resin brimer to the steel material.
0 micron, preferably about 20 to 50 micron, using a coating method such as a roll coater, bar coater, airless spray, brush coating, or ironing to achieve a uniform film thickness, and then heat the adhesive. harden.

Aromatic, aliphatic and/or alicyclic polyisocyanates used as curing agents in the mixed polyisocyanate of the present invention include phenylene diisocyanate, trirezisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, and trimethylpropane. Aromatic polyisocyanates such as 3 mole tolylene diisocyanate adduct, ethylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, heptamethylene diisocyanate, hexamethylene diisocyanate to 1 mole of trimethylpropane 3
These are aliphatic polyisocyanates such as molar adducts, and representative examples of alicyclic polyisocyanates include 1,4-cyclohexane diisocyanate.

The mixing ratio of aromatic polyisocyanate and aliphatic and/or alicyclic polyisocyanate is 95 to 5:
It is 5-95. The stability of polyurethane elastomers with aliphatic or polyurethane elastomers to light is poor, and when the content exceeds 95%, the physical properties of the polyurethane elastomers are poor.

Polyols as main ingredients include polyether polyols, polyester polyols, and polycaprolactones having an average molecular weight of 100 to 10,000, which are used as raw materials for polyurethane elastomers. If the average molecular weight of the polyol is less than 100 or more than 10,000, the physical properties of the polyurethane elastomer will be poor.

In addition, the metal-based fatty acid salts of group Ⅰ of the periodic table used as catalysts include formic acid, acetic acid, enanthic acid, capric acid, lauric acid, valmitic acid, stearic acid, oleic acid of magnesium, calcium, barium, zinc, cadmium, and mercury. Acids include oxalic acid, succinic acid, and tartrate. The amount of the metal fatty acid salt of Group 1 of the periodic table to be used is 0.001 to 10 wt%, preferably 0.002 to 2 wt%, based on the polyurethane elastomer.

The reason for this is to increase the stability of the polyurethane elastomer against light, and although the reason is not clear, the presence of metal fatty acid salts from group Ⅰ of the periodic table stabilizes the urethane bonds. I think that the.

The method for producing polyurethane elastomer in the present invention is a two-component reaction between a mixed polyisocyanate as a curing agent and a polyol as a main ingredient, and the mixed polyisocyanate is reacted in excess with the polyol to form a urethane prepolymer having NGO groups at the terminals. The polyurethane elastomer may be obtained by either a method of obtaining a polyurethane elastomer by further reacting the polyisocyanate with a polyol, or a method of obtaining a polyurethane elastomer from a mixed polyisocyanate as a curing agent and a polyol as a main ingredient at once. In this case, the time of addition of the metal-based fatty acid of group Ⅰ of the periodic table may be such that it is added to the curing agent or the main agent, or it may be added at the time of mixing the main agent and the curing agent.

The reaction temperature between mixed polyisocyanate and polyol is
By using a metal fatty acid belonging to Group 1 of the periodic table, the temperature is lower than in the case of no catalyst, which is 20 to 200°C, preferably 20 to 120°C.

The coloring pigment added to the polyurethane elastomer composition may be a coloring pigment containing any of known heat-resistant inorganic or organic pigment components. As pigment components,
For example, for white pigments, titanium white (rutile type titanium, anatase type titanium, etc.), zinc white, lithopone, lead white, and for green pigments, chromium oxide, chromium green (yellow and navy blue (potassium iron ferrocyanide)) Zinc green (mixture of zinc yellow and navy blue), chlorinated copper phthalocyanine green, phthalocyanine green, naphthol green, dibenzanthurone, malachite green lake, etc.

In addition, for blue pigments, ultramarine blue (natural products, synthetic products), navy blue, copper phthalocyanine blue, cobalt blue, phthalocyanine blue, fosto sky blue, indanthremble-1 red pigments, red lead, red iron oxide, basic chromium. Acid zinc, chromium permillion red, cadmium red, rose red, brilliant carmine (condensed azo tea world), brilliant scarlet, quinacridone red, lysole red, vermilion, thioindigo red, mingamya red, for yellow pigments, yellow lead , zinc yellow, yellow iron oxide,
Examples include titanium yellow, first yellow, Hansa yellow, auramine lake, penjijinero, and indanthrene yellow.

As for the pigment used in the polyurethane elastomer composition of the present invention, it is appropriate that the above-mentioned pigment component is contained in the polyurethane elastomer resin in an amount of 1 to 50% by weight. Coloring pigments are not appropriate if the addition ratio is too small because the coloring will not be vivid, and if the addition ratio is too large, the strength of the coating layer will be lowered, so it is not suitable.

In addition, the polyurethane elastomer composition of the present invention may contain fillers, fluorescent whitening agents, ultraviolet rays, etc., if necessary. ++Iv
*Place package 1 in IM I-R#+>'tAhn1.
ii. ←The method for applying the 2A polyurethane elastomer composition to steel materials via an adhesive etc. is as follows: (1) Precisely place the polyol, mixed polyisocyanate, coloring pigment, metal fatty acid salt, and other ingredients in a suitable container. (2) Spray painting using a two-component mixing spray paint machine.

The coating composition used in the present invention is preferably applied relatively thickly, for example to a thickness of 1 mm or more, and if the desired thickness cannot be achieved with two coats, multiple coats may be applied.

<Example> Next, the present invention will be explained in more detail based on examples.

[Example 1] ■-shaped copper sheet pile with a length of 5 m (dimensions: 400° x 130' x
13. After grid-blasting the concave surface of the Ota+m) and applying a paint-on chromate treatment agent (chromic acid compound), the steel sheet pile was heated to 100°C, and an amine-curing epoxy primer was applied by airless spray painting to a thickness of approximately 30°. When the brimer hardens due to the heat retained by the steel material and the temperature of the steel sheet pile reaches 60°C, 100 parts of polyester polyol as the main ingredient and 10 parts of chromium oxide as a green pigment are added.
1 part, A mixture containing 1 part of calcium tartrate as a metal fatty acid salt of group Ⅰ of the periodic table, and diphenylmethane-4,4'-diisocyanate and hexamethylene diisocyanate as hardening agents in a ratio of 7:3. A concave polyurethane elastomer-coated steel sheet pile having a film thickness of 2.5 11 va and colored green was obtained by spray-coating the steel sheet pile with 30 parts of Solution B using a two-component mixing spray paint machine.

[Example 2] Diphenylmethane-4,4'- was used instead of a mixture of diphenylmethane-4,4'-diisocyanate and hexamethylene diisocyanate in a ratio of 7=3 as a curing agent.
A concave polyurethane elastomer-coated steel sheet pile was obtained under exactly the same conditions as in Example 1, except that Solution B consisting of 30 parts of a 3-niar mixture of diisocyanate and hexamethylene diisocyanate was used.

[Example 3] A concave polyurethane elastomer-coated steel sheet pile was obtained under exactly the same conditions as in Example 1, except that 10 parts of yellow lead was used instead of chromium oxide as the pigment.

[Comparative Example 1] Diphenylmethane-4,4'-diisocyanate and hexamethylene diisocyanate were used in place of a 7:3 mixture of diphenylmethane-4,4'-diisocyanate as a curing agent.
A concave polyurethane elastomer-coated steel sheet pile was obtained under exactly the same conditions as in Example 1, except that liquid B consisting only of diisocyanate was used.

[Comparative Example 2] Completely the same as Example 1 except that liquid B consisting only of hexamethylene diisocyanate was used instead of a 7:3 mixture of diphenylmethane-4,4'-diisocyanate and hexamethylene diisocyanate as a curing agent. Concave polyurethane elastomer coated steel sheet piles were obtained under the same conditions.

[Comparative Example 3] A concave polyurethane elastomer-coated sheet pile was obtained under exactly the same conditions as in Example 1, except that calcium tartrate, which is a metal fatty acid salt of Group Ⅰ of the periodic table, was not used.

The following properties of the colored polyurethane elastomer-coated steel sheet pile thus obtained were evaluated, and the results are shown in Table 1.

(1) Vertical adhesive strength A vertical tensile test was conducted at room temperature using a tensile tester at a speed of 0.5 cm/sec.

(2) Impact strength Gardner set impact test at room temperature #Jfi (i-core 5/8”,
The impact S strength was determined using an impact body (5 kg). Cracks and peeling of the coating were checked using a pinhole detector.

(3) Hot water immersion test: 60°C, 3% NaCl, coating after immersion in solution for 30 days.

(4) Cathode peeling resistance The test material from which the 5 mm diameter coating material was removed was diluted with 3% Cf at room temperature.
The specimen was immersed in L solution, a voltage of 3.3 V was applied, and the specimen was left to stand for 30 days, and the distance from the initial hole to which the coating was removed was determined.

(5) Weather resistance An accelerated weather resistance test for up to 6,000 hours was conducted using a sunshine weather meter to investigate changes in color tone of the coloring material and conventional material. For color tone measurement, Suga Test Instruments Co., Ltd. 5
M-3 was used.

As is clear from Table 1, the colored polyurethane elastomer-coated copper material according to the present invention has impact resistance, hot water resistance, and cathode peeling resistance comparable to conventional coating materials, and weather resistance compared to conventional coating materials. It is easy to understand that the colored polyurethane elastomer-coated steel material of the present invention has great effects.

<Effects of the Invention> The steel material of the present invention is a heavy-duty anti-corrosion steel material that has mechanical properties as good as those of conventional products and is extremely excellent in colorability and uniformity.

Claims (1)

[Claims] (1) Aromatic polyisocyanate and aliphatic and/or alicyclic polyisocyanate are added to the surface of the steel material via a chemical conversion treatment layer and/or an adhesive layer at a weight ratio (95 to 5):
It is coated with a polyurethane elastomer layer containing a polyisocyanate mixed in a ratio of (5 to 95), b) a polyol, c) a coloring pigment, and d) a metal fatty acid salt of group II of the periodic table. A heavy corrosion-resistant steel material coated with a colored polyurethane elastomer.