JP3291076B2 - Polyurethane one-part composition and anticorrosion paint - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a one-part polyurethane composition for corrosion prevention, water resistance, impact resistance, electrical insulation, etc. of concrete or mortar structures, slate, steel materials, wood, etc., and to its anticorrosion paint. It is.

[0002]

2. Description of the Related Art Conventionally, anticorrosion paints have been used to prevent or repair concrete structures such as highways, bridge bridges, marine structures, and buildings, such as cracks, damage, and peeling. Furthermore, anticorrosion paints are used because they are highly corrosive to marine structures such as marine platforms and piers, and to metals that are constantly exposed to seawater or water, such as ships, bridges, sheet piles, and piles.

On the other hand, as a conventional anticorrosive paint, for example, a tar epoxy paint, coal tar enamel, asphalt or the like has been used, but there are problems in curability at low temperatures, impact resistance and the like. Urethane paint is also used,
Because it is a two-pack type, it is necessary to mix it before painting or use a special spraying machine. Further, urethane paints are troublesome due to complicated operations, mixing errors, inadequate mixing, and restrictions on the pot life, such as ripples on the coating surface, craters, and swelling of the coating film due to moisture.

[0004]

Under such circumstances, the present invention does not require mixing before coating, does not limit the blistering of the coating film and the pot life, and has the ability to follow cracks.
An object of the present invention is to provide a polyurethane one-part composition having excellent impact resistance and corrosion resistance and an anticorrosion paint containing the same.

[0005]

SUMMARY OF THE INVENTION The gist of the present invention is as follows.
The (ii) isocyanate group is substantially added to the urethane prepolymer containing a terminal isocyanate group obtained by reacting an organic polyisocyanate with a polyol whose main chain is formed only of carbon atoms and hydrogen atoms and / or a ricinoleic acid ester polyol. The first invention is a polyurethane one-pack composition comprising a block amine compound which generates a primary or secondary amino group by moisture without reacting with the first invention, and contains the polyurethane one-pack composition. The anticorrosion paint of the present invention is the second invention.

[0006] Examples of the polyol in which the main chain is formed only of carbon atoms and hydrogen atoms include polybutadiene and
Polyisobutylene, styrene-butadiene copolymer, styrene-isobutylene copolymer, acrylonitrile-butadiene copolymer, polychloroprene, isobutylene-
Polyols based on isoprene copolymers or the like, or polyols whose basic backbone is hydrogenated, or styrene-acrylate-hydroxyalkyl (meth)
Acrylic polyols such as acrylate copolymers, and the like, have an average hydroxyl value of 10 to 300 mgKOH /
g, preferably 30 to 200 mg KOH / g.

Examples of ricinoleic acid ester polyols include castor oil, partially dehydrated castor oil, partially acylated castor oil, transesterified castor oil with natural fats and oils, and esterified product of ricinoleic acid with a polyhydroxy compound. And the average hydroxyl value is 10 to 300 m
gKOH / g, preferably 30-200 mgKOH / g
It is.

When the above polyols are used in combination, the ratio is arbitrary. In addition to the above polyols, butanediol, hexanediol, an alkylene oxide adduct of bisphenol A or aniline, a polyoxyalkylene polyol, a polyester polyol, a polycaprolactone polyol, or the like may be appropriately used in combination.

Examples of the organic polyisocyanate to be reacted with the polyol include polymethylene polyphenyl polyisocyanate, liquid diphenylmethane diisocyanate, tolylene diisocyanate, tolidine diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, tetramethyl xylylene diisocyanate, isophorone diisocyanate, and naphthalene. Diisocyanate, hydrogenated diphenylmethane diisocyanate,
Alone or a mixture such as hydrogenated xylylene diisocyanate,
Or a buret form, an isocyanurate form, or a carbodiimide-modified product.

The polyol and the organic polyisocyanate are reacted by a known method in an NCO / OH equivalent ratio of 1.5 to 100, preferably 2.0 to 50.
The resulting urethane prepolymer has substantially two or more unreacted isocyanate groups at the molecular terminals.

Next, examples of the block amine compound to be mixed with the urethane prepolymer include ketimine, enamine, and oxazolidine. Specific examples include a primary amino group and / or a secondary amino group and a hydroxyl group. Compound having a group (hereinafter, referred to as compound (A))
Condensate of aldehydes or ketones, and two or more ketimines or oxazolidines in the molecule obtained by reacting the compound (A) with a ketimine alcohol or oxazolidine alcohol obtained from the aldehydes or ketones and the organic polyisocyanate. And the like.

Typical examples of the compound (A) include a compound having a primary amino group and a hydroxyl group, a compound having a secondary amino group and a hydroxyl group, and a compound having a primary amino group and a hydroxyl group. And a compound having a secondary amino group and two hydroxyl groups.

Specifically, for example, 2- (2-aminoethoxy) ethanol, ω-hydroxyhexylamine, N
-(2-hydroxyethyl) ethylenediamine, N-
(2-hydroxyethyl) piperazine, ethanolamine, diethanolamine, dipropanolamine, hexanolamine and the like.

The aldehydes or ketones include, for example, formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, trimethylacetaldehyde, valeroaldehyde, acrolein, crotonaldehyde, furfural, benzaldehyde,
Acetone, methyl ethyl ketone, methyl isobutyl ketone, diethyl ketone, diisobutyl ketone, methyl heptenone, cyclohexanone, isophorone, acetophenone and the like are mentioned. The reaction between compound (A) and aldehydes or ketones is carried out under known reaction conditions.

The amount of the block amine compound is from 1 to 50 parts by weight based on 100 parts by weight of the urethane prepolymer. When a block amine compound is added to the urethane prepolymer, an inorganic filler, an inorganic material-treated inorganic filler, a thixotropy-imparting agent, a plasticizer, a solvent, an adhesion-imparting agent, a coloring agent, a stabilizer, a leveling agent, a defoaming agent are further added. Agents, antioxidants, ultraviolet absorbers, flame retardants and the like may be appropriately blended.

[0016]

The polyurethane one-part composition and the anticorrosive paint of the present invention contain a block amine compound in the composition.
It is hydrolyzed with moisture in the air to form primary or secondary amines, and further reacts with free molecular terminal isocyanates to form urethane crosslinked polymers. This urethane prepolymer has high hydrophobicity, and the formed urethane crosslinked polymer is also excellent in corrosion prevention, water resistance, impact resistance, electrical insulation and the like.

[0017]

EXAMPLES Hereinafter, specific examples and effects of the present invention will be described with reference to examples and comparative examples. However, each example is, of course, for explanation, and does not mean a limitation of the inventive idea. In the examples, parts and% are based on weight.

Embodiment 1 FIG. To a planetary mixer, add 30 parts of calcium carbonate treated with lauric acid, 30 parts of dioctyl phthalate, 30 parts of talc, and 0.5 part of carbon, knead the mixture at room temperature for 15 minutes, and then knead the mixture at 100 ° C. while vacuuming. The dehydration operation was performed for 1 hour. Next, a polybutadiene polyol (average hydroxyl value: 46.5 mg KOH
/ G) with 2,4 tolylene diisocyanate in NCO /
100 parts of a urethane prepolymer having a terminal NCO group content of 9.0% obtained by reacting at an OH equivalent ratio of 4.3, 3 moles of ketimine alcohol obtained by equimolar reaction of hexanolamine with cyclohexanone, and buretated hexamethylene 77 parts of the blocked amine compound obtained from 1 mol of diisocyanate and 50 parts of xylene were mixed with the kneaded material in the planetary mixer and kneaded at room temperature for further 15 minutes to obtain a one-pack polyurethane composition. This is shot-blasted in advance and then primer-treated steel pipe,
It was uniformly applied with a thickness of 2 mm. After the application, the coating was left at room temperature for 2 weeks to evaluate the performance. Table 1 shows the results.

[0019]

Comparative Example 1 In the polybutadiene polyol (average hydroxyl value 46.5 mgKOH / g) of Example 1,
2,4 Tolylene diisocyanate reacted at NCO / OH equivalent ratio = 4.3, resulting in a terminal NCO group content of 9.0%
"Polyoxypropylene glycol (average hydroxyl value 56 mg KO)
H / g) and polyoxypropylene triol (average hydroxyl value 42 mg KOH / g) were mixed at a weight ratio of 2 to 1, and this mixture was mixed with 2,4 tolylene diisocyanate and N 2
Terminal NCO obtained by reaction at CO / OH equivalent ratio = 2.1
100 parts of a urethane prepolymer having a group content of 9.0% ”was used, and the other steps were the same as in Example 1. Table 1 shows the results
Shown in

[0021]

[Table 1]

In the table, "tear strength" and "elongation at break" were measured according to JIS-K6301. "Water absorption"; measured according to JIS-K7114. "Insulation resistance"; steel pipe coated with a one-part polyurethane composition (20
0A × 500) was set in a 3% saline solution, and the insulation resistance was measured at 500 V with an ohmmeter. "Impact test"; measured according to JIS-K5664.

Embodiment 2 FIG. In the polybutadiene polyol (average hydroxyl value 46.5 mgKOH / g) of Example 1,
2,4-tolylene diisocyanate was reacted at an NCO / OH equivalent ratio of 4.3 to obtain a terminal NCO group content of 9.0.
% Urethane prepolymer 100 parts ”, but instead of“ polybutadiene polyol (average hydroxyl value 46.5 mg KO
H / g) and partially acetylated castor oil (average hydroxyl value 11
0 mg KOH / g) at a weight ratio of 1: 1, and the mixture is mixed with 2,4-tolylene diisocyanate and NCO
/ OH 100 parts of a urethane prepolymer having a terminal NCO group content of 9.0% ”obtained by reacting at an equivalent ratio of 3.07, and then using“ hexanolamine ”in an equimolar reaction with cyclohexanone in Example 1. 2- (2-Ethyl obtained by reacting diethanolamine and propionaldehyde in equimolar amounts as a block amine compound instead of 77 parts of a blocked amine compound obtained from 3 mol of ketimi alcohol and 1 mol of buretted hexamethylene diisocyanate) 31 parts of a trioxazolidine compound obtained by reacting 1 mol of buretated hexamethylene diisocyanate with 3 mol of -1,3-oxazolidin-3-yl) -ethanol "and using the same method as in Example 1 to prepare polyurethane. A liquid composition was obtained. This one-part polyurethane composition was coated on a Teflon-coated iron plate with a bar coater so as to have a coating thickness of 350 μm, and cured at room temperature for 7 days to obtain a film. The physical properties of these coated films based on the concrete anticorrosive paint were measured. Table 2 shows the results.

Comparative Example 2 The procedure of Example 2 was repeated, except that the “polyurethane one-part composition obtained in Comparative Example 1” was used instead of the “polyurethane one-part composition” of Example 2. Table 2 shows the results.

Comparative Example 3 In place of the “polyurethane one-part composition” of Example 2, “commercial acrylic paint” was used,
Others were performed similarly to Example 2. Table 2 shows the results.

[0026]

[Table 2]

However, in the table, "Appearance of coating film"; JIS-K5
Measured according to 400. Coating uniformity, flow, unevenness,
We examined the peeling and rated good for good and bad for bad. "Crack followability": The coating film is fixed on a flat plate that can fix both ends of the coating film and can reciprocate at intervals of 0 to 2 mm. One cycle of reciprocating 0 to 2 mm per minute is one cycle.場合 indicates that the sample was not broken even after 100 cycles, and x indicates that the sample was broken by 100 cycles. "Moisture permeability"; measured according to ASTM E-96. "Chlorine permeability"; 3% saline on one side in a water tank that can hold a coating film (70 mm square on one side) in the middle
Distilled water is placed on the opposite side, and the chloride ion concentration in the distilled water is measured by potentiometric titration, and the amount of permeation is determined by Formula 1.

[0028]

(Equation 1)

"Oxygen permeability" was measured with an oxygen barrier tester (manufactured by Nissan Sangyo Co., Ltd.). "Alkali resistance"; J
It measured according to IS-K5400. The film is immersed in a saturated solution of calcium hydroxide for 30 days, and the film is blistered, and the presence or absence of cracks and peeling is checked. If there is none, then ○, and if there is, X. "Salt resistance"; immersed in 3% saline for 3 months to check for abnormalities in the coating. If there is none, then ○, and if there is, X. “Heat resistance”; placed in an oven at a temperature of 200 ° C. for 24 hours to check the coating film for melt and crack. If there is none,
Those that are present are marked as x.

[0030]

The polyurethane one-part composition and the anticorrosion paint of the present invention are (1) a one-part type and a two-part type,
No mixing work is required, work efficiency is good and there is no restriction on pot life. (2) Curing in air is quick, and the cured coating film does not foam, but is resistant to water and corrosion.
It has excellent properties such as impact resistance and electrical insulation, and is excellent as a paint for concrete or mortar structures, slate, steel, wood, etc.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-26522 (JP, A) JP-A-6-239953 (JP, A) JP-A-5-310879 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) C08G 18/00-18/87 C09D 5/08 C09D 175/00-175/12

Claims (3)

(57) [Claims] (1) A urethane prepolymer having a molecular terminal isocyanate group obtained by reacting an organic polyisocyanate with a polyol and / or a ricinoleate ester polyol having a main chain formed only of carbon atoms and hydrogen atoms, B) a one-pack polyurethane composition comprising a block amine compound which does not substantially react with an isocyanate group and generates a primary or secondary amino group by water; A compound having a secondary amino group and a hydroxyl group, a compound having a secondary amino group and a hydroxyl group, a compound having a primary amino group, a secondary amino group and a hydroxyl group, and a compound having a secondary amino group and two Ketimine, enamine or oxine using compound (A) selected from the group consisting of compounds having a hydroxyl group One-component composition polyurethane which is a Zorijin compound. 2. The one-pack polyurethane composition according to claim 1, wherein the polyol and / or ricinoleate polyol whose main chain is formed only of carbon atoms and hydrogen atoms has an average hydroxyl value of 10 to 300 mgKOH / g. 3. An anticorrosion paint comprising the one-part polyurethane composition of claim 1 or 2.