JPH02160880A - Corrosion-resistant coating and composition - Google Patents

Abstract

PURPOSE:To reduce foaming and to improve long-term corrosion resistance, etc., by compounding an active hydrogen component consisting of a polyol and polyamines which are two specified arom. diamines and an org. polyisocyanate compd. as a two packing type. CONSTITUTION:A polyamine (b) is obtd. by compounding an arom. diamine (i) having one long-chain alkyl substituent at least at the ortho position to the amino group (e.g. 1-methyl-3,5-diethyl-2,4-diaminobenzene) with an arom. diamine (ii) wherein at least one position ortho to the amino groups of polyphenyl-polymethylene-polyamineamine with a wt. ratio of the component (i) to the component (ii) is substd. by chlorine group (e.g. 2,6,2'6'-tetrachloro-4,4'- diaminodiphenylmethane). An active hydrogen-contg. component (A) consisting of 30-70wt.% polyol (a) which is pref. a polyether polyol or a castor oil polyol and the component (b) and an org. polyisocyanate compd. (B) wherein the equivalent ratio of the sum of amino group and OH group of the component A to free NCO group is 0.9-1.5:1 are compounded as a two-package type.

Description

[Detailed description of the invention] [Industrial application fields] The present invention relates to anticorrosive coatings and compositions.

[Prior Art] For the purpose of anti-corrosion protection of iron structures, there are two-component solvent-free polyurethane resin paints that have good drying properties and are made of polyether polyol or polyester polyol and polyisocyanate.

[Problems to be Solved by the Invention] However, this two-component solvent-free polyurethane resin paint has a problem that it tends to foam.

Also, is this paint resistant in environments exposed to very low temperatures? There are problems in that the Jr 2'l properties are insufficient and the f1 properties are also insufficient for long-term anticorrosion performance.

[Means for Solving the Problems] The present inventors have conducted intensive studies to find an anticorrosion coating and an x1 product that has extremely low foaming, is strong, has excellent performance at low temperatures, and has excellent long-term corrosion resistance. As a result, the present invention was achieved. That is, the present invention provides a two-component anticorrosive coating agent consisting of an active hydrogen-containing component consisting of a polyol and a polyamine and an organic polyisocyanate compound, in which the polyamine has one linear alkyl substitution at at least the ortho position to 7 amino groups. An anticorrosion coating agent characterized by using an aromatic diamine (a) having a group and an aromatic diamine (b) in which at least one ortho position to an amino group of a polyphenyl-polymethylene polyamine is substituted with a chlorine group. , and an anticorrosive coating composition comprising a combination of a silicone epoxy primer and the above anticorrosive coating agent.

In the present invention, the aromatic diamine (a) includes phenylene diamine, naphthylene diamine and the general formula (wherein, X is a C+ to C4 alkylene group, -0--C-
-S Oa- or a direct bond) and an alkyl substituted product at the ortho position of a polyphenylpolymethylene polyamine (preferably an alkyl substituted product of phenylenediamine).

Such amines have at least one (preferably two) alkyl substituents at ortho positions to one amine group and two alkyl substituents at ortho positions to the other amino group. Examples include aromatic diamines having groups.

The alkyl lit substituent of the above amine has 1 to 1 carbon atoms.
8 alkyl substituents, such as methyl, 1, ethyl, propyl, isopropyl, and butyl groups, preferably straight chain alkyl groups having 1 to 3 carbon atoms.

Specific examples of such aromatic diamine (a) include l
, 3-diethyl-2,4-diaminobenzene, 1-methyl-3,5-diethyl-2,G-diaminobenzene, I
-Methyl-3,5-diethyl-2,4-diaminobenzene, l-methyl-2,4-diethyl-3,5-diaminobenzene,! -Methyl-2,4-diethyl-3,6-diaminobenzene,! , 3°5-triethyl-2,6-diaminobenzene, and mixtures of two or more thereof. Preferred among these are 1-methyl-3,5-diethyl-2°-diaminobenzene, 1-methyl-3,5-diethyl-2°4-diaminobenzene, and mixtures thereof.

The aromatic diamine (b) is an aromatic diamine in which at least one (preferably two) positions ortho to the amine group of a polyphenyl-polymethylene polyamine obtained by condensation of aniline-formaldehyde is substituted with a chloro group. can be mentioned.

Specific examples of such aromatic diamines (b) include 2
．． 2'-dichloro-4,4'-diaminodiphenylmethane, 2,3.3'-)lichloro-4,4'-diaminodiphenylmethane, 2,3.2',3'-tetrachloro-
4,4'-diaminodiphenylmethane, 2. G, 2',
Examples include 6'-tetrachloro-441-diaminodiphenylmethane.

Among these, preferred are 2,3.2',3'-tetrachloro-4,4'-diaminodiphenylmethane, 2
, 8.2'B + -tetrachloro-4,4'-diaminodiphenylmethane and mixtures thereof.

Examples of polyols include polyether polyols, castor oil polyols, polyester polyols, polymer polyols, polybutadiene polyols, and these two.
Includes mixtures of more than one species.

As polyether polyols, low molecular polyols (
Ethylene glycol, propylene glycol, 1.4-
Trifunctional polyols such as butanediol and 1,3-butanediol; glycerin, trimethylolpropane,
pentaerythritol, trifunctional or higher functional Q polyols such as sucrose, etc.), azines (alkanolamines such as triethanolamine, N-methyljetanolamine, aliphatic polyamines such as ethylenediamine,
Alkylene oxides of compounds containing at least two active hydrogen atoms (alkylene oxides having 2 to 4 carbon atoms, such as ethylene oxide, propylene, etc.) oxide,
butylene oxide, etc.), ring-opening polymers of alkylene oxides (ring-opening polymerization of tetrahydrofuran, polytetramethylene ether glycol, etc. produced by hydrolysis), etc. Castor oil-based polyols include those whose main component is ricinoleic acid. , general industrial castor oil, refined castor oil and its derivatives, such as castor oil fatty acid diglycerides, monoglycerides and mixtures thereof; polyester polyols include 1 polycarboxylic acids (aliphatic polycarboxylic acids such as adipic acid, maleic acid, di- Polyester polyols, lactone polyesters (such as polycaprolactone) obtained by the condensation of polyols (low-molecular-weight polyols or polyether polyols as mentioned above) with phosphoric acids, aromatic polycarboxylic acids such as phthalic acid; polymer polyols Examples of polyols include those obtained by polymerizing vinyl nitride (acrylonitrile and/or styrene, etc.) in polyols (polyether polyols, polyester polyols, etc.); polybutadiene polyols include those obtained by polymerizing butadiene with a radical initiator containing hydroxyl groups. and those obtained by adding a compound that forms a hydroxyl group, such as ethylene oxide, to an active terminal polymer obtained by polymerizing butadiene using an anionic polymerization catalyst such as sodium or lithium. etc.

Among these polyols, polyether polyols and castor oil-based polyols are preferred, and particularly preferred are polyether polyols and castor oil-based polyols having a molecular fi of 800 to 5,000.

The weight ratio of aromatic diamine (a) and aromatic diamine (b) used is usually (a): (b) = I:l ~ 5:1
Preferably 2:! ~3:! It is. (a) of (b)
If the weight ratio exceeds 5, the pot life will be extremely short when mixed with the organic polyisocyanate compound, and the coating material formed will also be hard and brittle, resulting in a decrease in impact resistance. In addition, if the weight ratio of (a) to (b) is less than 1, the stability of the active hydrogen-containing component itself will deteriorate, crystals may precipitate, and the coating material formed by mixing with the organic polyisocyanate compound may not be sufficient. It does not exhibit sufficient hardness and is insufficient for the desired performance.

The content of polyol, aromatic diamine (
a), the total weight of aromatic diamine (b) usually contains 30 to
70% by weight, preferably 40-60% by weight. When the polyol content is less than 30% by weight, the fluidity of the resin decreases, resulting in poor workability.

When the amount is more than 70% by weight, the resulting coating film becomes extremely soft and insufficient for the desired performance.

Next, as the organic polyisocyanate compound, those conventionally used in the production of polyurethane can be used. Such an incyanate compound has a carbon number (NG
Excluding the carbon in the O group <) 2-18 aliphatic isocyanates, such as hexamethylene diisocyanate (HDI)
, lysine diylene ananate: Alicyclic incyanate having 4 to 15 carbon atoms, such as inphorone isocyanate, dicyclohexylmethane isocyanate: Isocyanate, such as γ-isocyanatepropyltrimethoxysilane, γ-incyanatepropylmethyl Jetoxysilane, γ-Isocyanate Propyltrimethoxysilane (E I S) Aroaliphatic incyanates having 8 to 15 carbon atoms [e.g. xylylene diisocyanate] Aromatic isocyanates having 6 to 20 carbon atoms [e.g. / or 2.6-tolylene diisocyanate) (
TDI), crude TDI, 2,4'- and/or 4,4'
- diphenylmethane diisocyanate (MDI), crude MDI (crude diaminophenylmethane (condensation product of formaldehyde and aromatic amines (anilines) or mixtures thereof: diaminophenylmethane and small amounts (e.g.
~20% by weight) of trifunctional or higher functional polyamine>
Phosgenate: polyallyl polyisocyanate CP
API) 1 etc.]: and modified products of these incyanates (urethane group, carbodiimide group, allophanate group, urea group, biuret group, uretdione group, uretonimine group, isocyanurate group, oxazolidone group-containing modified products, etc.): and Examples include isocyanates other than those described in Japanese Patent Application No. 1991/1991 and mixtures of two or more thereof. Among these, preferred are aliphatic incyanates and modified products thereof.

The organic polyisocyanate compound may be used as an organic polyisocyanate component having a terminal isocyanate group by reacting it with a polyol and/or an aromatic diamine (a) or an aromatic diamine (b), or it may be reacted with a polyol and/or an aromatic diamine (b) in advance. /Or aromatic diamine (a) 1 It may be reacted with aromatic diamine (b) and used as an active hydrogen-containing component having a terminal active hydrogen group.

The anticorrosive coating of the present invention comprises polyol, aromatic diamine (
It consists of two liquids: an active hydrogen-containing component consisting of a) and an aromatic diamine (b), and an organic polyisocyanate compound. The mixing ratio of the two liquids is such that the equivalent ratio of the sum of amino groups and hydroxyl groups to the free incyanate groups of the active hydrogen component is usually (L9:1 to 1.5:1, preferably I:1 to 1.5:1).
3:l.

Other components can be added to the anticorrosive coating of the present invention as required. Other ingredients include inorganic fillers (calcium carbonate, barium sulfate, talc, clay, silica powder, etc.)
Reinforcing agents (carbon black, white carbon, colloidal silica, etc.), colorants (titanium white, cobalt green, red iron, etc.), catalysts (lead octylate, dibutyltin dilaurate, stannath octoate, triethylamine, triethylenediamine, etc.), resins Modifier (silane coupling agent, organopolysiloxane, etc.),
Examples include water absorbing agents (synthetic zeolite, quicklime, soluble anhydrite, etc.), antisettling agents, and antiaging agents.

The amount of other components is usually 100% in the case of an inorganic filler based on the total weight of the active hydrogen-containing component and the organic polyisocyanate.
% or less, preferably 10-90%, for reinforcing agents usually 0-10%, preferably 2-5%, for colorants usually 100% or less, preferably 1-90%, for catalysts usually 1% or less, preferably 0.5% or less, resin modifiers usually 3% or less, preferably 0-1%1, water-absorbing agents usually 10% or less, preferably 1-5%, sedimentation In the case of inhibitors, it is usually 10% or less, preferably 1 to 5%, and in the case of anti-aging agents, it is usually 3% or less, preferably 1% or less.

When applying the anticorrosive coating of the present invention to iron, it is necessary to first apply a silicone epoxy primer to the iron and then apply the anticorrosive coating onto the primer surface.

The above-mentioned primer is composed of an epoxy resin having two or more epoxy groups in one molecule, an aminoalkoxysilane, a monoepoxy compound, and if necessary a lysocyanate compound (Japanese Patent Application No. 1983-2493 GO).
and epoxy resins having two or more epoxy groups in one molecule, amine compounds, monoepoxysilanes, and if necessary monoepoxy compounds and/or incyanate compounds (Japanese Patent Application No. 333018/1982)
can be given.

The primer is usually used in the form of a solution, and when used as a primer for steel materials, metal powder is used to improve corrosion resistance. Metal powders include aluminum powder,
Examples include zinc powder. Most preferred is zinc powder. Examples of the zinc powder include metal zinc powder and metal zinc alloy bundles (Zn/At alloy powder, Zn/AI/Mg alloy powder, etc.) which are usually used in zinc-rich primers, and metal zinc powder is preferred. The particle size of zinc powder is usually 1 to 5 microns, and its shape is usually spherical.

The amount of zinc powder used or blended is usually 40% in the dry coating film.
-80% by weight, preferably 50-70% by weight.

Pigments may also be used with zinc powder. Typically used pigments include talc, mica, barium sulfate, glass powder, titanium oxide, red iron oxide, lead cyanamide, and zinc chromate. These pigments are preferably surface-treated with a silane coupling agent in advance. This treatment has many advantages, such as less water adsorbed on the surface of the pigment, better compatibility with the brimer, less increase in viscosity even when a high pigment content is added, improved workability, and low cost.

Application of the coating composition of the present invention to iron is as follows.

First, if necessary, a silicone epoxy primer containing 50 to 70% by weight of zinc powder is applied to the sandblasted iron surface. Brimer can be applied by brushing, roller, spraying, etc.

Allow the applied brimer to dry thoroughly at room temperature.

Preferred drying conditions are 3 hours to 24 hours at 5°C to 50°C.
time, preferably 8 hours to 12 hours.

The film thickness of the brimer after drying is usually 5μ to 200μ, preferably 1Oμ to 100μ.

A coating according to the invention is then applied onto the brimer surface.

The mixing ratio of the two liquids of the active hydrogen-containing component and the organic polyisocyanate compound is such that the equivalent ratio of the sum of free incyanate groups, amine groups, and hydroxyl groups is usually 0.9:I-1.
, 5:l preferably l:I~! , 3:1.

The coating method involves thoroughly stirring and mixing a predetermined amount of an active hydrogen-containing component and an organic polyisocyanate compound, degassing if necessary, and then applying the mixture to the brimer surface to form a uniform resin color.

In the case of the present invention, since the time required to reach gelation after mixing the two components of the active hydrogen-containing component and the organic polyisocyanate compound is short, the application of the coating material to the brimer surface is
Application by a two-liquid one-head gun airless spray or a two-liquid two-gun airless spray is more preferred.

The above-mentioned airless spray machine is not subject to any particular restrictions on its usability, and is equipped with a mixer that mixes two liquids, each of which is separately metered and fed at the same time, of an active hydrogen-containing component and an organic polyisocyanate compound, and discharges the mixture as one liquid. Prepare,
Any device that can mix and spray two liquids in a short period of time, or one that has two spray nozzles and can mix the two liquids in the form of a mist at the tip may be used.

The respective temperatures of the active hydrogen-containing component and the Yoki polyisocyanate compound affect the gelation time, but can be arbitrarily changed as long as the gelation time does not interfere with the work.

The thickness of the cured coating can be arbitrarily changed depending on the use and application environment, but in severe environments where the anticorrosive coating and composition of the present invention are to be applied,
Usually 500μ to 200μ, preferably 700μ to 15
Used in 00μ.

[Examples] The present invention will be further explained below with reference to Examples, but the present invention is not limited thereto. Parts in the examples are parts by weight.

The various test methods used in the Examples and Comparative Examples are as follows:
It is as follows.

(a) Paint film appearance-1 (foaming property) The appearance of the finished paint film was observed under a microscope with a magnification of 50 times, and the relative degree of foaming was compared.

Judgment: ○---- Almost no foaming, no pinholes △---~- Foaming is observed ×-- 1-- Significant foaming (b) Paint film appearance - 2 (smoothness) Visually inspect the appearance of the finished paint film. Observations were made and relative comparisons were made regarding smoothness.

Judgment: Very smooth △－－－－Slightly poor smoothness ×----not smooth (c) Adhesiveness (I) Primary adhesion Adhege 3 tester in dry condition Vertical tension by (Elzmeter) Tests were conducted and relative comparisons were made.

(t+) After immersing the secondary adhesion test pieces in warm salt water (50°C, 3% salt water) for one month, a vertical tensile test was performed using an adhesion tester (Elcometer) for relative comparison.

Judgment: O-111 Good adhesion Δ--- Adhesion slightly poor ×-111 Poor adhesion (d) Impact resistance - A DuPont drop impact test was conducted at 60 DEG C. for relative comparison.

Judgment O----Good impact resistance Δ---- Impact resistance slightly poor ×-----Poor impact resistance A tensile test was conducted to measure the ice accretion force and relative comparisons were made.

Judgment O - Ice can be removed with a weak force Δ - - Ice can be removed with a moderately strong force × - 111 Ice cannot be removed without a fairly strong force (f) Corrosion resistance test test piece placed in salt water Immersion anti-corrosion coating tester (Shindenshi Kogyo)
The changes over time in the alternating current electrical resistance of the coating films were measured and compared relative to each other.

Judgment 〇----Electric resistance does not change much Δ----
Production example 1 with a large decrease in electrical resistance. Epikote 828 (bisphenol A type epoxy resin, epoxy equivalent: about 185, manufactured by Yuka Shell) 370 was added to the reaction pot.
parts, 120 parts of ethylenediamine, KBM-402 (γ-
992 parts of glycidoxypropyl methyljethoxysilane (Shin-Etsu Chemical Co., Ltd.) and 250 parts of methyl ethyl ketone were added and reacted at 50°C for 5 hours. Next, after cooling to room temperature, 25 parts of ethanol was added and diluted to obtain a silicone epoxy primer.

Add 35 parts of this silicone epoxy primer to 60 parts of zinc powder.
5 parts of methyl ethyl ketone were kneaded in a closed kneader.
1 part, and mixed and diluted to obtain a silicone epoxy primer containing zinc dust.

Example 1 80 parts of alkylene oxide adduct of glycerin (molecular weight too, hydroxyl value 1 [i8) as polyol, DETDAC main component as aromatic diamine (a), l-
30 parts of methyl-3,5-diethyl-2,4-diaminobenzene and I-methyl-3,5-diethyl-2,6-diaminobenzene (manufactured by Ethyl Corporation), as the aromatic diamine (b), 2. 10 parts of G,2',8''-tetrachloro-4,4'-diaminodiphenylmethane were weighed and mixed and heated to 130''C to mix. Then, it was cooled to 60°C and dibutyltin dilaurate was added to 0.
After adding 1 part and stirring uniformly, it was further cooled to 30°C, and 40 parts of barium sulfate, 40 parts of talc, 5 parts of titanium oxide, 5 parts of red iron oxide, and 2 parts of synthetic zeolite were added and mixed uniformly to obtain an active hydrogen-containing component. .

To 100 parts of this active hydrogen-containing component, 110 parts of an organic polyisocyanate compound (Deerane) TPA-100 (hexamethylene diisocyanate-based polyisocyanate, manufactured by Asahi Kasei Industries, Ltd.) was mixed and cured to obtain the anticorrosive coating of the present invention.

Example 2 Diglyceride of castor oil fatty acid (
The anticorrosive coating of the present invention was prepared in the same manner as in Example 1, except that URICH-53 (manufactured by Ito Oil Co., Ltd.) was used.

Example 3 Alkylene oxide adduct of glycerin (molecular weight to
oo, 47 parts of hydroxyl value 1 (i8) were charged into the reaction vessel,
Dehydration was carried out for 1 hour by heating to 110° C. under reduced pressure of 3 mmHg. Next, 53 parts of inphorone diisocyanate was added to the mixture, and the mixture was reacted at 100°C for 3 hours under a nitrogen stream to obtain a prepolymer. 150 parts of Duranate TPA-100 (hexamethylene diisocyanate-based polyisocyanate, Asahi Kasei Kogyo) was added to this prepolymer at 70°C.
The mixture was stirred for 1 hour to obtain an organic incyanate-containing component. The NGO content of the prepolymer was 19%.

100 parts of the active hydrogen-containing component of Example 1 was mixed with 134 parts of this organic polyisocyanate compound and cured to obtain the anticorrosive coating of the present invention.

Comparative Example 1 The same procedure as in Example 1 was carried out except that the aromatic diamine (a) of Example 1 was not used at all.

Comparative Example 2 Instead of the aromatic diamine (a) of Example 1, an alkylene oxide adduct of ethylenediamine (molecular negative 300
, hydroxyl value 748) was used in the same manner as in Example 1.

Table 1 Example 4 On a sandblasted iron plate, the zinc powder-containing silicone epoxy primer obtained in Production Example 1 was applied with a brush.
It was dried at room temperature for 8 hours. Primer dry film thickness is 50μ
Met. Next, the anticorrosive coating obtained in Example 1 was applied for 10 minutes using a two-part mixing spray device (manufactured by Toshi Engineering).
The anti-corrosion coating composition of the present invention was prepared by spraying so that the coating thickness was 0.00 μm. The performance test results are shown in Table-2.

Example 5 An anticorrosive coating composition of the present invention was prepared in the same manner as in Example 4, except that the anticorrosive coating obtained in Example 2 was used as the anticorrosive coating. The performance test results are shown in Table-2.

Comparative Example 3 A coating film was formed in the same manner as in Example 5, except that the coating material obtained in Comparative Example 2 was used as the anticorrosive coating material.

The performance test results are shown in Table-2.

Comparative Example 4 A coating film was formed using the anticorrosive coating obtained in Example 1 without using any primer. The performance test results are shown in Table-2.

Table-2 By using it, long-term corrosion protection performance can be expected.

4. Due to foaming (...), the surface of the coating is smooth and the coefficient of friction is lowered, which weakens the adhesion of water and the like, allowing it to be used as a thinner for ice and sea.

5. Since the curing process is extremely fast, it is possible to shorten the time required for the next process, resulting in excellent workability.

6. Excellent curability at low temperatures.

[Effects of the Invention] The anticorrosive coating and composition of the present invention have the following effects.

1. It solves the problem of foaming that was a concern with conventional two-component solvent-free urethane anticorrosive paints.

2. The coating film formed is extremely tough and exhibits excellent impact resistance even at low temperatures.

3. Since the above effects are achieved in combination with a silicone epoxy primer, the anticorrosive coating and composition of the present invention can be applied to steel structures such as buildings, machinery, storage tanks,
Corrosion protection for a variety of applications including bridges, land structures on steel roads, sea berths, offshore oil drilling rigs, quay cranes, marine structures such as offshore bridges, water gates, ships operating in icy areas, various vibrating lines, and steel pipe piles. Can be used as a coating.

Patent applicant: Ishikawajima-Harima Heavy Industries Co., Ltd. Nippon Paint Co., Ltd. Sanyo Chemical Industries, Ltd.

Claims (1)

[Scope of Claims] 1. A two-component anticorrosion coating comprising an active hydrogen-containing component comprising a polyol and a polyamine and an organic polyisocyanate compound, in which the polyamine has at least one linear chain at the ortho position to the amino group. Aromatic diamine (a) having an alkyl substituent, and aromatic diamine (b) in which at least one ortho position to the amino group of polyphenyl-polymethylene polyamine is substituted with a chlorine group.
An anticorrosion coating characterized by using. 2. The anticorrosive coating according to claim 1, wherein the polyol is a polyether polyol or a castor oil polyol. 3. An anticorrosive coating composition comprising a silicone epoxy primer and the coating material according to claim 1 or 2 in combination. 4. After applying the silicone epoxy primer, in a two-component anti-corrosion coating consisting of an active hydrogen-containing component consisting of a polyol and a polyamine and an organic polyisocyanate compound, as the polyamine, at least one ortho position with respect to the amino group is added. Applying an anti-corrosion coating consisting of an aromatic diamine (a) having a linear alkyl substituent and an aromatic diamine (b) having at least one ortho position to the amino group of a polyphenyl-polymethylene polyamine substituted with a chlorine group. Anti-corrosion coating method.