JP2000281940A - Urethane resin composition for heavy corrosionproof coating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a urethane resin composition for a heavy corrosionproof coating excellent in adhesion to a metallic material such as a steel plate and a steel stock and resistance to adhesion deterioration under corrosion accelerating circumstances, and to provide heavy corrosion-proof coating materials excellent in cathode peeling resistance and crosscut peeling resistance in steel plates on effecting electric anticorrosion by utilizing this heavy corrosionproof coating urethane resin composition. SOLUTION: A heavy corrosion-proof coating urethane resin composition comprises (a), as its major agent, a polyol, (b), as a curing agent, a polyisocyanate, and (c), as a modifier, an alkylphenol, as its essential components, or (a), as its major agent, a polyol, (b'), as a modifying curing agent, an addition reaction product of (i) a polyisocyanate and (ii) an alkylphenol as the essential components. A heavy corrosionproof coating material is obtained by incorporating a pigment component into this heavy corrosionproof coating urethane resin composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a urethane resin composition for heavy duty anticorrosion paint. More specifically, the present invention relates to a urethane resin composition for heavy duty anticorrosion paint which has excellent adhesiveness to metal materials such as steel plates and steel materials, and particularly has excellent adhesive deterioration resistance under a corrosion-promoting environment. The present invention also relates to a heavy-duty anticorrosion paint using the composition, which is excellent in cathodic peeling resistance particularly during cathodic protection and also excellent in crosscut peeling resistance.

[0002]

2. Description of the Related Art Generally, urethane resins are produced by polyaddition of an isocyanate compound and a compound having active hydrogen (for example, polyol). Such urethane resin can be thermoplastic or thermosetting by appropriately selecting the specific composition of the isocyanate compound and the compound having active hydrogen, or by changing the ratio of both compounds, and can be hard or hard. It can be soft, solid or foamy. Because of its excellent elasticity, toughness, abrasion resistance, electrical insulation, chemical resistance, low-temperature properties, etc., it is widely used for foams such as heat insulating materials, molded products such as insulating materials, elastomers, paints, adhesives, etc. Applied to the application.

In this case, since the isocyanate compound has high reactivity and may hinder handling, it has long been practiced to temporarily protect and block the isocyanate-reactive group. For example, modifiers such as amides and phenols are used for the purpose of the block.
For example, it is described in the literature, Ang. Chem., 59, 257 (1947).
Examples of using alkylphenols as blocking agents include:
In polyurethane sealant applications, an example in which nonylphenol is used as a blocking agent for the purpose of imparting storage stability has already been known, and is described in Examples in JP-A-2-86614.

Further, as a urethane resin coating composition, particularly as an inner coating for waterworks, in order to supplement water resistance in an environment where a temperature gradient exists inside and outside a water pipe and to improve adhesion to a substrate, A method of blending a modifier selected from a phenol (alkyl derivative) -modified coumarone resin or a phenol-modified petroleum resin, a styrenated phenol resin or a modified cyclopentadiene-based resin is already known (JP-A-63-183967). )

However, an object of the present invention is to improve the adhesiveness to steel sheets and steel materials, particularly to the deterioration with time of the coating film adhesion when exposed in a corrosion-promoting environment such as a salt spray environment, for example, for use in ships and marine steel structures. Polyurethane resin compositions for heavy duty anticorrosion paints in which an alkylphenol is blended as a modifying agent or a polyisocyanate obtained by an addition reaction of an alkylphenol is used as a modifying curing agent.

In fact, the conventional urethane resin-based heavy anticorrosion paint film has a problem that the adhesiveness when exposed in applications of ships and marine steel structures decreases with time, and there is a problem in the adhesive deterioration resistance. I have. Therefore, a heavy duty anticorrosion coating film using such a conventional urethane resin composition for heavy duty anticorrosion paints has sufficient cathodic peeling resistance and crosscut peeling resistance during cathodic protection (an environment in which adhesion deterioration is particularly problematic). I can't say that. Here, the cathodic peelability at the time of cathodic protection is a test to determine whether or not the coating film can withstand the use of cathodic protection, and attach a zinc or aluminum anode to the center of the test plate containing the cross cut.
It is a test to determine the suitability by immersing in seawater or 3% saline and observing whether or not blistering or peeling occurs in the coating film around the cross cut. And a method of judging suitability by observing the degree of corrosion around the cross cut, the state of blisters and peeling.

[0007]

DISCLOSURE OF THE INVENTION The present invention relates to a steel sheet which has been an object of a conventional urethane resin composition for heavy duty anticorrosion paint.
Provided is a urethane resin composition for heavy duty anticorrosion paint which has excellent adhesion to metal materials such as steel and resistance to adhesion deterioration in a corrosion-promoting environment, and uses the urethane resin composition for heavy duty anticorrosion paint to produce electricity. It is an object of the present invention to provide a heavy-duty anticorrosion paint excellent in cathodic peeling resistance and cross-cut peeling resistance of a steel sheet during corrosion prevention.

[0008]

Means for Solving the Problems The present inventors have conducted research to achieve the above-mentioned object, and have prepared a urethane resin composition containing an alkylphenol as an essential component as a modifier. Steel plates, adhesion to metal materials such as steel materials, and adhesion deterioration resistance when exposed in a corrosion-promoting environment such as a salt spray environment are significantly improved.
The heavy-duty anticorrosive paint using the urethane resin composition has been found to greatly improve the cathodic peeling resistance and the crosscut peeling resistance during cathodic protection, which is an environment where adhesion deterioration resistance is more demanded. Completed the invention.

That is, the present invention provides (a)
A urethane resin composition for heavy duty anticorrosion paints, characterized by comprising a polyol, (b) a polyisocyanate as a curing agent, and (c) an alkylphenol as a modifier. And, in the urethane resin composition for heavy duty anticorrosion paint, (a) epoxy polyol obtained by adding alkanolamine to a bisphenol A type epoxy resin as a main component polyol, and (b) polyisocyanate as a curing agent is tolylene diisocyanate. Methylol propane adduct, (c) alkyl phenol as a modifier is tertiary butyl phenol, nonyl phenol,
A compounding ratio of (b) an isocyanate group of a curing agent to (a) a hydroxyl group of a main agent and (c) a hydroxyl group of a modifier, which is one or a combination of two or more selected from tertiary amyl phenol and octyl phenol. (B / a / c) is preferably 1 / 0.5 to 1.5 / 0.1 to 0.8 (molar ratio).

Further, the present invention is characterized in that it comprises, as essential components, a polyol as a main component and an addition reactant of (a) a polyisocyanate and (b) an alkylphenol as a (b ') modified curing agent. Urethane resin composition for heavy duty anticorrosive paint. In this urethane resin composition for heavy duty anticorrosion paint, (a) an epoxy polyol obtained by adding an alkanolamine to a bisphenol A type epoxy resin, and (b ′) a modified curing agent comprising (a) a polyisocyanate Is an addition reactant with one or a combination of two or more selected from tertiary butyl phenol, nonyl phenol, tertiary amyl phenol and octyl phenol as (b) alkyl phenol, and The reaction addition ratio of the isocyanate group of (a) to the hydroxyl group of (b) is 1 / 0.1 to 0.8 (molar ratio), and the mixing ratio of the isocyanate group of the modified curing agent to the hydroxyl group of (a) the main agent is 1 /
It is preferably 0.8 to 5.0 (molar ratio).

Further, the present invention is a heavy-duty anticorrosion paint comprising a urethane resin composition for a heavy-duty anticorrosion paint as described in any of the above, and a pigment component blended therein.

Hereinafter, the present invention will be described in detail. The polyol used as the (a) main agent of the urethane resin composition of the present invention and the heavy duty anticorrosive paint using the composition may be a compound having two or more alcoholic hydroxyl groups in one molecule, for example, diisopropanolamine, An alkanolamine such as diethanolamine is added to an epoxy resin such as a bisphenol A-type epoxy resin or a novolak phenol-type epoxy resin to obtain an epoxy resin, an acrylic monomer having an alcoholic hydroxyl group such as a hydroxyester of methacrylic acid, and vinyl-polymerized. Addition of ethylene oxide and propylene oxide to polyester polyols obtained by polycondensation of dibasic acids such as phthalic acid and polyhydric alcohols such as glycerin and polyhydric alcohols and polyphenols such as bisphenol A. polymerization Examples thereof include polyether polyols obtained by the above method, and epoxy polyols obtained by adding an alkanolamine, particularly diethanolamine, to a bisphenol A type epoxy resin are preferable from the viewpoint of the balance between cost and performance.

The bisphenol A type epoxy resin used for this purpose has various degrees of polymerization, but in the case of high solids or solventless orientation and in the case of emphasis on coating workability, it is a liquid with a low degree of polymerization at room temperature. When importance is attached to adhesion to an adherend, those having a high degree of polymerization are preferred. Examples of the low polymerization degree product include Yuka Shell Epoxy Co., Ltd., trade name, Epicoat 828 (degree of polymerization 0),
Examples of high polymerization degree products include Epototo YD-927 (polymerization degree 11) manufactured by Toto Kasei Co., Ltd.

The polyisocyanate used as the curing agent (b) in the urethane resin composition for heavy duty anticorrosion paints of the present invention may be any compound having two or more isocyanate groups in one molecule. Isocyanate (hereinafter abbreviated as TDI), adduct of trimethylolpropane (hereinafter abbreviated as TMP) of TDI, isocyanurate which is a trimerized product of TDI, 4,4′-diphenylmethane diisocyanate (hereinafter abbreviated as MDI) ) And polymeric diphenylmethane diisocyanate (hereinafter, referred to as
Xylylene diisocyanate (hereinafter abbreviated as XDI) as a non-yellowing type (discoloration under exposure to ultraviolet light) is a non-yellowing type (discoloration under exposure to ultraviolet light). Hexamethylene diisocyanate (hereinafter abbreviated as HDI), isophorone diisocyanate (hereinafter abbreviated as IPDI), hydrogenated XDI and hydrogenated MDI
TD from the point of balance between cost and performance
Preferred are TMP adducts of I and polymeric MDI.

The alkylphenol used for the (c) modifier or (b ') modifier curing agent of the urethane resin composition of the present invention is a compound having an alkyl group at the ortho, meta or para position of the phenol. Good, industrially easily available ones include, for example, p-tert-butylphenol, p-nonylphenol, p-tert-amylphenol and p-octylphenol. Preferably, it is an alkylphenol having an alkyl group having a side chain at the para-position, but from the viewpoint of the environment, a compound other than paranonylphenol is preferable.

The (b ') modified curing agent used in the urethane resin composition for heavy duty anticorrosion paints of the present invention is a compound synthesized by the addition reaction of the above-mentioned alkylphenol with the above-mentioned polyisocyanate. The addition reaction ratio between the hydroxyl group and the hydroxyl group is preferably between 0.1 and 0.8 mol per 1 mol of the isocyanate group. The addition reaction conditions are preferably 1 to 5 hours under heating at 50 to 100 ° C.

The compounding ratio of the urethane resin composition for heavy duty anticorrosion paint containing (a) the main component, (b) the curing agent and (c) the modifying agent as essential components is as follows: Preferably, the hydroxyl group of (a) the main agent is 0.5 to 1.5 mol and the hydroxyl group of the (c) modifier is 0.1 to 0.8 mol.

When the (b ′) modified curing agent is used instead of the (b) curing agent and (c) the modifying agent, the compounding ratio of the urethane resin composition for a heavy duty anticorrosion paint is (b ′) ) The hydroxyl group of (a) the main component is preferably in the range of 0.8 to 5.0 mol per 1 mol of the isocyanate group of the modified curing agent. It is also within the scope of the present invention to use the (b ′) modified curing agent together with the (b) curing agent and the (c) modifier, and the mixing ratio in this case can be easily analogized from the above. it can.

Next, the heavy duty anticorrosion paint of the present invention is obtained by blending a pigment component (colored pigment, extender pigment) with any of the urethane resin compositions for heavy duty anticorrosion paint described above. , A thixotropic agent and a solvent can be blended and dispersed. Examples of the pigment used in the heavy duty anticorrosion paint of the present invention include talc, kaolin, calcium carbonate, glass flake and flake mica as those classified as extender pigments. Further, carbon black, titanium dioxide, and the like can be given as those classified as the coloring pigments.

The mixing ratio of the pigment to the vehicle is preferably in the range of 100 to 200% by weight in the case of the extender which determines the corrosion resistance. This is because the water vapor permeability of the coating film, which is a measure of the anticorrosive property, is minimized within the range of the blending ratio of the extender. On the other hand, in the case of a coloring pigment, it can be blended in an appropriate ratio according to a desired degree of coloring, but is generally in the range of 0 to 100% by weight based on the resin component.

Thixotropic agents used as necessary in heavy duty anticorrosion paints are intended to increase the film thickness per coating, reduce the sagging of the coating, further reduce the viscosity during coating and improve workability. It is added in. In the present invention, polyethylene oxide wax, fatty acid amide wax, organic bentonite and the like can be used. The mixing ratio of the thixotropic agent to the coating composition (the coating base (base agent) before adding the curing agent is 100 parts by weight) is preferably about 0.6 to 1.2 parts by weight. As the solvent, an aromatic solvent, a ketone solvent or a mixed solvent thereof is suitable.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Why the urethane resin composition of the present invention has excellent adhesion deterioration resistance to metal materials such as steel plates and steel materials, and why heavy anticorrosion paints using the composition are used in the case of electrolytic protection Whether the steel sheet has excellent resistance to cathodic peeling and cross-cut peeling or the exact mechanism thereof is unknown, but is presumed as follows.

First, in the case of a urethane resin composition comprising a main agent, a curing agent, and a modifier, first, a system in which an alkylphenol is blended as a modifier has a smaller change in density over time than a system without a modifier. Therefore, it contributes to the improvement in curing shrinkage and cross-cut peeling resistance. Secondly, since the urethane resin composition containing the modifying agent can obtain a cured product having a higher density than that of the non-modifying agent-comprising system, the free volume of the curing system is filled with the modifying agent. As a result, intrusion of water vapor, oxygen, and the like from the outside is suppressed, so that corrosion is suppressed, which contributes to improvement in resistance to adhesion deterioration. Third, the urethane resin composition containing the modifier has a lower elastic modulus than that of the non-compounded resin composition, and a flexible cured product can be obtained. This is thought to be due to the plasticizing action of the modifier. That is, even if the cured product is distorted by an external force, the generated stress is suppressed to a low level, which contributes to the improvement in the adhesive deterioration resistance. Fourth, the urethane resin composition containing the modifying agent has a lower rate of change in weight over time than the urethane resin composition containing other compounds. That is, loss due to sublimation, run-off, etc. of the modifier is small, and it is considered that defects such as micropores generated in the cured product due to the loss are small, and this leads to improvement in adhesion deterioration resistance and the like.

In the case of a urethane resin composition comprising a main agent + modified curing agent, each of the above-mentioned modifying effects is more improved than a system comprising a main agent + curing agent + modifying agent. This is because the structure of the modified hardener is in a form in which the alkylphenol, which is the modifier, is forcibly taken in by an addition reaction, so that the proportion of the modifier present in the composition in a free state is small, This is because the effect of filling the free volume is more effectively exhibited.

The preparation and use of the heavy duty anti-corrosion paint using the urethane resin composition of the present invention can employ conventionally known methods. For example, a paint base is prepared by mixing and dispersing (1) (a) a main ingredient, (c) a modifier, a pigment (color pigment, extender pigment), a thixotropic agent, and the like at a predetermined ratio using a ball mill or the like. (2) A hardening agent is prepared by mixing (b) a curing agent together with a solvent with the paint base agent, stirring and mixing. (3)
The heavy anticorrosive paint thus prepared is applied to a blast steel plate by brush coating or the like so as to have an appropriate dry thickness of, for example, about 300 μm, and the coated film is cured before use.

[0026]

Next, the present invention will be described in detail with reference to examples.
In Examples 1 to 8 and Comparative Examples 1 to 3, the base material + the curing agent +
Examples relating to the urethane resin composition for heavy duty anticorrosion paint comprising a modifier, Examples 9 to 16 and Comparative Examples 4 to 5 are each a main component +
Examples relating to the urethane resin composition for heavy duty anticorrosion paint comprising a modified curing agent, Examples 17 to 18 and Comparative Examples 6 to 7, respectively,
It is an example relating to a heavy duty anticorrosion paint using the urethane resin composition for heavy duty anticorrosion paint.

The evaluation of the urethane resin composition of the present invention in the examples was carried out as follows. (1) Adhesive force (kg / cm ² ) Initial value and salt spray 100 according to ASTM D4541
Measurements were taken after 0, 2000 and 3000 hours, respectively. The crosshead speed of the tensile tester was 10 (mm / min).

The anticorrosion paint of the present invention was evaluated as follows. (2) Cross-cut peeling resistance According to JIS K 5400 (9.1), salt spray 700
Measured after time. (3) Cathodic peeling property during cathodic protection According to JIS K 5400 (8.5.3), a zinc electrode (-1000 to -1) was placed at the center of a cross-cut test piece.
060 mV SCE), immersed in 3% saline at 20 ° C., and indicated large, medium and small cathode peeling after 700 hours.

Example 1 Bisphenol A having a polymerization degree of 0 was used as the main polyol.
50% by weight of an epoxy polyol having a hydroxyl equivalent of 202 g / eq obtained by adding diisopropanolamine (commercially available high-grade reagent) to a type epoxy resin (trade name, Epikote 828, manufactured by Yuka Shell Epoxy Co., Ltd.) Solution (solvent is toluene: methyl isobutyl ketone
(Hereinafter abbreviated as MIBK): 10.0 g of methyl ethyl ketone (hereinafter abbreviated as MEK) = 50: 30: 20 weight ratio mixture),
75% by weight ethyl acetate solution of trimethylolpropane adduct of tolylene diisocyanate (hereinafter abbreviated as TDI-TMP) having an isocyanate group equivalent of 323 g / eq as a polyisocyanate for a curing agent (Takeda Pharmaceutical Co., Ltd.)
24.0 g of trade name, Takenate D-103H), 3.7 g of p-tBu-Ph (hereinafter abbreviated as p-tBu-Ph) as an alkylphenol as a modifier, and toluene: MIBK: MEK = 50 as a solvent. 51.3 g of a 30:20 weight ratio mixed solvent was blended, stirred, dissolved and mixed to prepare a varnish. At this time, the mixing ratio of isocyanate group of the curing agent / hydroxyl group of the main agent was 1.00 / 0.68.
(Molar ratio), the compounding ratio of isocyanate group of curing agent / hydroxyl group of modifier is 1.00 / 0.32 (molar ratio)
Met. The mixing ratio of isocyanate group of the curing agent / total hydroxyl group of the main agent and the modifier is 1.00 / 1.00.
(Molar ratio).

After casting the varnish on a blast steel plate,
After curing for 3 weeks at 23 ° C. and 65 R.H.% (relative humidity), a coated plate coated with a cured urethane resin composition film having a thickness of about 300 μm was prepared.

Next, the coated plate was subjected to a salt concentration of 5% by weight and a temperature of 3%.
Exposure to a salt spray environment at 5 ° C.
The adhesive strength between the cured film and the blasted steel sheet after 00 and 3000 hours was measured under the above conditions and compared with the initial value. As a result, no deterioration was observed in the adhesive strength, and excellent adhesive durability was confirmed. Table 1 shows the results.

Example 2 The same formulation as in Example 1 was prepared by mixing the proportions shown in Table 1, ie, the molar ratio of isocyanate group of the curing agent / hydroxyl group of the main agent / hydroxyl group of the modifying agent = 1.00 / 1.02 / 0.51. A urethane resin composition was obtained according to the same procedure as in Example 1 except that the urethane resin composition was mixed at a ratio. Similarly, the adhesive strength after spraying with salt water was as excellent as the initial value.

Example 3 5.5 g of paranonylphenol (hereinafter abbreviated as p-C9-Ph) was used as a modifier, and a molar ratio of isocyanate group of a curing agent / hydroxyl group of a main agent / hydroxyl group of a modifying agent = 1.00 /
After compounding at 0.68 / 0.32, a urethane resin composition for heavy duty anticorrosion paint was obtained according to the same procedure as in Example 1. Similarly, the adhesive strength after spraying with salt water was as excellent as the initial value.

Example 4 The same formulation as in Example 3 was prepared by adding a curing agent isocyanate group / base hydroxyl group / modifier hydroxyl group molar ratio = 1.
A urethane resin composition was obtained according to the same procedure as in Example 1 except that it was blended at a ratio of 00 / 1.02 / 0.51. Similarly, the adhesive strength after spraying with salt water was as excellent as the initial value.

Example 5 4.1 g of paratertiary amylphenol (hereinafter abbreviated as p-tAm-Ph) was used as a modifier, and the molar ratio of isocyanate group of the curing agent / hydroxyl group of the main agent / hydroxyl group of the modifying agent = 1 After blending at 0.000 / 0.68 / 0.32, a urethane resin composition for heavy duty anticorrosion paint was obtained according to the same procedure as in Example 1. Similarly, the adhesive strength after spraying with salt water was as excellent as the initial value.

Example 6 The same formulation as in Example 5 was prepared except that the molar ratio of curing agent isocyanate group / base hydroxyl group / modifier hydroxyl group = 1.
A urethane resin composition was obtained according to the same procedure as in Example 1 except that it was blended at a ratio of 00 / 1.02 / 0.51. Similarly, the adhesive strength after spraying with salt water was as excellent as the initial value.

Example 7 5.1 g of paraoctylphenol (hereinafter abbreviated as p-Oc-Ph) was used as a modifier, and a molar ratio of isocyanate group of a hardener / hydroxyl group of a main agent / hydroxyl group of a modifier = 1.00 /
After compounding at 0.68 / 0.32, a urethane resin composition for heavy duty anticorrosion paint was obtained according to the same procedure as in Example 1. Similarly, the adhesive strength after spraying with salt water was as excellent as the initial value.

Example 8 The same formulation as in Example 7 was prepared by adding a curing agent isocyanate group / base hydroxyl group / modifier hydroxyl group molar ratio = 1.
A urethane resin composition was obtained according to the same procedure as in Example 1 except that it was blended at a ratio of 00 / 1.02 / 0.51. Similarly, the adhesive strength after spraying with salt water was as excellent as the initial value.

Comparative Example 1 A urethane resin composition was obtained according to the same procedure as in Example 1 without using a modifier, but the adhesive strength after spraying with salt water was low.

Comparative Example 2 3.5 g of phenol (hereinafter abbreviated as Ph) was used as a modifier, and the molar ratio of isocyanate group / hydroxyl group of main agent / hydroxyl group of modifier = 1.00 / 0.68 / 0 .
After blending at 32, a urethane resin composition for heavy duty anticorrosion paint was obtained according to the same procedure as in Example 1, but the adhesive strength after spraying with salt water was similarly low.

COMPARATIVE EXAMPLE 3 The same formulation as in Comparative Example 2 was prepared by adding a curing agent isocyanate group / base hydroxyl group / modifier hydroxyl group molar ratio = 1.
A urethane resin composition was obtained according to the same procedure as in Example 1 except that it was blended at a ratio of 00 / 1.02 / 0.51. Similarly, the adhesion after salt spray was low.

Table 1 shows the compounding ratios and evaluation results of Examples 1 to 8 and Comparative Examples 1 to 3.

[0043]

[Table 1]

Example 9 The same polyisocyanate solution 2 used in Example 1
4.0 g and 3.7 g of p-tBu-Ph were charged into a 100 ml four-neck flask equipped with a stirrer, thermometer and reflux condenser, and reacted at 80 to 90 ° C. for 3 hours to prepare a modified hardener. . At this time, the addition reaction ratio of p-tBu-Ph to the isocyanate group in the polyisocyanate is 1.00 / 0.
32 (molar ratio).

Thereafter, the same epoxy polyol solution as in Example 1 was used as the main agent, and the compounding ratio of the modified curing agent isocyanate group / main agent hydroxyl group was adjusted to 1.00 / 1.00 (molar ratio) according to the composition shown in Table 2. ) Was obtained in the same manner as in Example 1 except that the urethane resin composition for a heavy-duty anticorrosive paint was obtained. The adhesive strength after spraying with salt water increased rather than the initial value, indicating excellent resistance to adhesive deterioration with time.

Example 10 The amount of p-tBu-Ph used in the synthesis of the modified curing agent was 5.9 g, and
The addition reaction ratio of p-tBu-Ph is 1.00 / 0.51 (molar ratio)
A urethane resin composition was obtained in the same procedure as in Example 9, except that Similarly, the adhesive strength after spraying with salt water increased rather than the initial value, indicating excellent resistance to adhesive deterioration over time.

Example 11 The alkylphenol used for the synthesis of the modified curing agent was p-C9-P
h, 5.5 g, and the addition reaction ratio of p-C9-Ph to the isocyanate group in the polyisocyanate is 1.00 / 0.3.
A urethane resin composition was obtained in the same procedure as in Example 9 except that the molar ratio was changed to 2. Similarly, the adhesive strength after spraying with salt water increased rather than the initial value, indicating excellent resistance to adhesive deterioration over time.

Example 12 The amount of p-C9-Ph used for synthesizing the modified curing agent was 8.8 g,
P-C9 for isocyanate groups in polyisocyanate
A urethane resin composition was obtained in the same procedure as in Example 9, except that the addition reaction ratio of -Ph was set to 1.00 / 0.51 (molar ratio). Similarly, the adhesive strength after spraying with salt water increased rather than the initial value, indicating excellent resistance to adhesive deterioration over time.

Example 13 The alkylphenol used for the synthesis of the modified curing agent was p-tAm-
Ph was 4.1 g, and the addition reaction ratio of p-tAm-Ph to isocyanate groups in the polyisocyanate was 1.00 / 0.3.
A urethane resin composition was obtained in the same procedure as in Example 9 except that the molar ratio was changed to 2. Similarly, the adhesive strength after spraying with salt water increased rather than the initial value, indicating excellent resistance to adhesive deterioration over time.

Example 14 The amount of p-tAm-Ph used for the synthesis of the modified curing agent was 6.5 g, and
The addition reaction ratio of p-tAm-Ph is 1.00 / 0.51 (molar ratio)
A urethane resin composition was obtained in the same procedure as in Example 9, except that Similarly, the adhesive strength after spraying with salt water increased rather than the initial value, indicating excellent resistance to adhesive deterioration over time.

Example 15 The alkylphenol used for the synthesis of the modified curing agent was p-Oc-P
h 5.1 g, and the addition reaction ratio of p-Oc-Ph to the isocyanate group in the polyisocyanate is 1.00 / 0.32.
A urethane resin composition was obtained in the same procedure as in Example 9 except that the molar ratio was changed. Similarly, the adhesive strength after spraying with salt water increased rather than the initial value, indicating excellent resistance to adhesive deterioration over time.

Example 16 The amount of p-Oc-Ph used for synthesizing the modified curing agent was 8.1 g,
P-Oc for isocyanate groups in polyisocyanate
A urethane resin composition was obtained in the same procedure as in Example 9, except that the addition reaction ratio of -Ph was set to 1.00 / 0.51 (molar ratio). Similarly, the adhesive strength after spraying with salt water increased rather than the initial value, indicating excellent resistance to adhesive deterioration over time.

Comparative Example 4 Phenol (hereinafter abbreviated as Ph) 3.5 for the synthesis of the modified hardener
g, the addition reaction ratio of Ph to the isocyanate group in the polyisocyanate is 1.00 / 0.32 (molar ratio).
A urethane resin composition was obtained in the same procedure as in Example 9, except that Adhesion after salt spray was low.

Comparative Example 5 The procedure of Example 1 was repeated except that 5.58 g of Ph was used in the synthesis of the modified curing agent, and the addition reaction ratio of Ph to the isocyanate groups in the polyisocyanate was 1.00 / 0.51 (molar ratio). In the same manner as in Example 9, a urethane resin composition was obtained. Similarly, the adhesive strength after salt spray was low.

Table 2 summarizes the compounding ratios and evaluation results of Examples 9 to 15 and Comparative Examples 4 and 5.

[0056]

[Table 2]

Example 17 The same epoxy polyol resin (EPO-0) solution 1 as in Example 1
To 0.0 g, 3.7 g of a modifier p-tBu-Ph and 17.6 g of a 60% by weight toluene solution of a phenol-modified coumarone resin were mixed and dissolved, and then 27.3 flat talc as an extender was dissolved.
g, 0.3 g of carbon black as a color pigment and 4.7 g of titanium dioxide were mixed and dispersed in a ball mill for 30 minutes to prepare a paint base agent. To this paint base agent, as a curing agent, the same 75% ethyl acetate solution of TDI-TMP as in Example 1 (Takenate D-103H, manufactured by Takeda Pharmaceutical Co., Ltd.) was used.
4.0 g, the same toluene as in Example 1 as solvent: MIBK: M
11.6 g of a mixed solvent having a weight ratio of EK = 50: 30: 20 was mixed, stirred and mixed to prepare a heavy-duty anticorrosive paint. At this time, the compounding ratio of the curing agent isocyanate group / base hydroxyl group / modifier hydroxyl group was 1.00 / 0.68 / 0.
32 (molar ratio).

This heavy anticorrosive paint was brush-coated on a blast steel plate so that the dry film thickness was about 300 μm, to prepare a coated plate. After curing for 2 weeks, a zinc electrode for cathodic protection was connected to the center of the cross cut, and immersed in 5% saline for 1 week. Good corrosion resistance was confirmed without any product made by cathode peeling.
Further, a similar coated plate was prepared for a rusted steel plate instead of the blasted steel plate, and a cross-cut test was performed on the coated plate under salt water spraying under the same conditions as in Example 1 to measure the peel width after exposure for 700 hours. The results are shown in Table 3. The peel width was extremely small, showing excellent corrosion protection.

Example 18 The same epoxy polyol resin (EPO-0) solution 1 as in Example 1
0.0 g, 60% by weight of phenol-modified coumarone resin
After blending and dissolving 17.6 g of a toluene solution, 27.3 g of flat talc as an extender, 0.3 g of carbon black as a coloring pigment, and 4.7 g of titanium dioxide were blended and dispersed in a ball mill for 30 minutes. Was prepared.

[0060] TD is added to this paint base agent as a modifying hardener.
75% ethyl acetate solution of I-TMP (Takeda Pharmaceutical Co., Ltd.)
Isocyanate group / hydroxyl group molar ratio obtained by adding 3.7 g of p-tBu-Ph to 24.0 g of Takenate D-103H).
27.7 g of an adduct solution of 1.00 / 0.32, and toluene: MIBK: MEK = 50: 3 as the solvent as in Example 1.
0: 11.6 g of a mixed solvent of 20 parts by weight was blended and stirred.
A heavy duty anticorrosive paint was prepared by mixing.

The anticorrosion paint was evaluated in the same manner as in Example 17, and the results are shown in Table 3. The peel width is extremely small,
It showed excellent corrosion protection.

Comparative Examples 6 and 7 Other than that no modifier was blended (Comparative Example 6) or blending was performed using 3.5 g of Ph as a modifier (Comparative Example 7),
A heavy-duty anticorrosion paint was prepared in the same procedure as in Example 17, and the properties were evaluated. The results are shown in Table 3. The cathodic peeling property during cathodic protection was remarkable, and the cross-cut peeling width under salt spray was large, resulting in insufficient corrosion protection.

[0063]

[Table 3]

[0064]

Industrial Applicability The urethane resin composition for heavy duty anticorrosion paints of the present invention has excellent resistance to deterioration of metal materials such as steel plates and steels, and therefore is required to have long-term durability in a corrosion-promoting environment. Useful as a material for In particular, when used in non-tar heavy anticorrosion paints for ships and steel structures, etc., which are urgently required to be converted from tar epoxy resin paints, the cathodic peeling resistance during cathodic protection and the cross Shows excellent properties of corrosion protection, such as the width of cut peel.

Continued on front page F term (reference) 4J034 BA08 CA02 DF16 DF22 DG03 DG04 DG14 DK02 DP18 HA01 HA07 HB07 HC03 HC12 HC17 HC22 HC35 HC52 HC64 HC67 HC71 HC73 MA01 QA03 RA07 4J038 DG051 DG261 JA64 KA03 KA08 NA03 PC02

Claims (5)

[Claims] 1. A urethane resin composition for heavy duty anticorrosion paint, comprising (a) a polyol as a main ingredient, (b) a polyisocyanate as a curing agent, and (c) an alkylphenol as an essential ingredient as a modifier. object. (2) The polyol of the main agent is bisphenol
Epoxy polyol obtained by addition reaction of alkanolamine to A-type epoxy resin, (b) polyisocyanate of curing agent is trimethylolpropane adduct of tolylene diisocyanate, (c) alkylphenol of modifier is tertiary butylphenol, nonylphenol, tercia A compounding ratio of (b) an isocyanate group of a curing agent to (a) a hydroxyl group of a main agent, and (c) a hydroxyl group of a modifying agent, which is one or a combination of two or more selected from liamylphenol and octylphenol ( b / a / c) is 1 / 0.5 to 1.5 / 0.1 to 0.8 (molar ratio)
2. The urethane resin composition for a heavy duty anticorrosive paint according to claim 1, wherein 3. A heavy-duty anticorrosive paint comprising, as essential components, a polyol as a main component and an addition reactant of (a) a polyisocyanate and (b) an alkylphenol as essential components as a (b ′) modified curing agent. Urethane resin composition for use. 4. The (a) main component polyol is bisphenol
Epoxy polyol obtained by addition reaction of alkanolamine to A-type epoxy resin, (b ') modified curing agent is (a) trimethylolpropane adduct of tolylene diisocyanate as polyisocyanate, (b) tertiary butyl phenol as alkylphenol, It is an addition reactant of one or a combination of two or more selected from nonylphenol, tertiary amylphenol and octylphenol, and the reaction addition ratio between the isocyanate group of (a) and the hydroxyl group of (b) is 1 / 0.1
0.8 (molar ratio), and the compounding ratio of the isocyanate group of the modified curing agent to the hydroxyl group of the (a) main agent is 1 / 0.8 to 5.0.
4. The urethane resin composition for a heavy-duty anticorrosive paint according to claim 3, wherein the molar ratio is (molar ratio). 5. A heavy-duty anticorrosion paint comprising a urethane resin composition for heavy-duty anticorrosion paint according to claim 1 and a pigment component.