JPH0681821B2 - Coating composition for concrete or mortar structure - Google Patents

Description

The present invention relates to a coating composition for concrete or mortar structure for the purpose of anticorrosion, water resistance, impact resistance, etc. of concrete or mortar structure.

BACKGROUND ART In recent years, cracking, damage, peeling and the like of concrete structures such as expressways, bridges, marine structures and buildings have become a serious social problem.

The cause is that the concrete structure cracks.
It is considered that the reinforcing steel inside corroded and its volume expanded.

In particular, this phenomenon is often seen in areas near the coast and in concrete structures that come into direct contact with seawater, so it is considered that chlorine ions have some influence.

Usually these are called "salt damage".

Furthermore, it is said that, in addition to the influence of chlorine ions, the influence of water, carbon dioxide, oxygen, etc. is also large in the alkaline aggregate reaction, neutralization and the like.

The inventors of the present invention have made extensive studies in order to solve the problem of slanting, and as a result, have provided the present invention. That is, a polyol and an organic polyisocyanate compound, consisting of a polyurethane resin reacted with an NCO to active hydrogen ratio of 0.60 to 1.50, wherein the polyol is a ricinoleic acid ester polyol alone or a mixture of a ricinoleic acid ester polyol and a polyamine. , And the average hydroxyl value is 30 to 45
0mgKOH / g, or the sum of average hydroxyl value and amine value is 30 to 45
A coating composition for concrete or mortar structures, which is characterized by having 0 mgKOH / g.

As the ricinoleic acid ester polyol of the polyol component used in the present invention, for example, general industrial castor oil, purified castor oil or a product obtained by transesterification of castor oils and polyether polyols, or ricinoleic acid Examples thereof include a polyhydroxylated polyester obtained by an esterification reaction with an active hydrogen-containing compound or a polyether polyol.

Further, as the polyamine to be mixed with the ricinoleic acid ester polyol, for example, diaminodiphenylmethane, methylenebis (orthochloroaniline) (MOCA),
Chloroaniline-formalin condensate, phenylenediamine, tolylenediamine, ethylenediamine, piperazine, alkylated aromatic polyamine, polybutadiene skeleton polyamine, polybutadiene-acrylonitrile copolymer polyamine, obtained by reacting an excess equivalent amount of an organic polyisocyanate compound. Examples thereof include a polyamine compound obtained by further reacting a terminal amine-containing compound with a polyamine, or a urethanized polyamine obtained by treating the terminal isocyanate-containing compound according to the method described in JP-A-59-109513.

Such a polyol component, in the case of ricinoleic acid ester polyol alone, the average hydroxyl value is 30 to 450 mgKOH / g, or in the case of a mixture of polyamine mixed with ricinoleic acid ester polyol, the sum of the average hydroxyl value and amine value is 30 to It should be 450 mg KOH / g.

Therefore, the mixing ratio of the ricinoleic acid ester polyol and the polyamine is such that the sum of the average hydroxyl value and the amine value is 30 to
There is no particular limitation as long as the ratio is in the range of 450 mgKOH / g.

If the average hydroxyl value or the sum of the average hydroxyl value and amine value is less than 30 mgKOH / g, salt permeability and water permeability are poor, while if it exceeds 450 mgKOH / g, the coating film is hard and brittle. The crack followability is also poor.

The average hydroxyl value of the polyol component of the present invention is 30
~ 450mgKOH / g, or the sum of average hydroxyl value and amine value 30 ~
Within the range of 450mgKOH / g, other polyols,
For example, a polyol whose molecular main chain is formed of only carbon atoms such as polybutadiene polyol and acrylic polyol; specifically, poly BD R45HT (manufactured by ARCO), PBG-200.
0, PBG-3000 (all manufactured by Nippon Soda Co., Ltd.), Polytail (manufactured by Mitsubishi Kasei Co., Ltd.), Nicalite-H 470 (manufactured by Nippon Carbide Co., Ltd.) and the like may be used in combination.

Next, as the organic polyisocyanate compound used as the isocyanate component of the polyurethane resin, tolylene diisocyanate, diphenylmethane diisocyanate (MDI), crude diphenylmethane diisocyanate, liquid diphenylmethane diisocyanate, naphthalene diisocyanate, xylylene diisocyanate (XDI),
Hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), hydrogenated MDI, hydrogenated X
Examples include DI and HDI burettes, HDI isocyanurates, and IPDI isocyanurates.

Further, the organic polyisocyanate compound may be reacted with the polyol component in advance and used as a urethane prepolymer having a terminal NCO.

When reacting the above-mentioned polyol and organic polyisocyanate compound, the ratio of NCO to active hydrogen is 0.60 to 1.50.
Is.

If the NCO to active hydrogen ratio is less than 0.60, water resistance, water permeability is poor, concrete surface, adhesion to the top coating is poor, and if it exceeds 1.50, foaming occurs, appearance is poor, The desired film cannot be obtained.

In the coating composition of the present invention, a solvent, a plasticizer, an inorganic filler, a pigment, a water absorbing agent, an anti-settling agent, a color separation preventing agent, a catalyst and the like may be used in combination, if necessary. Further, a urethane or epoxy-based primer may be used together to improve the adhesion to the concrete surface or as a measure against surface moisture.

The concrete or mortar structure of the present invention configured as described above has the following features.

(1) The concrete or mortar structure coated with the composition of the present invention has a chlorine ion permeability, a moisture permeability,
Oxygen permeability and carbon dioxide gas permeability are low, and therefore, the effect of preventing corrosion of steel frames and reinforcing bars in the structure and its own alkali-aggregate reaction and neutralization is extremely excellent.

(2) Even if a crack is formed in the concrete or mortar structure, the crack followability is great and the durability is improved.

Examples of the present invention will be shown below.

In the examples, "part" means part by weight and "%" means% by weight.
Are shown respectively.

Production Example (1) A urethanized polyamine was obtained according to the following method.

Polyoxypropylene glycol (average hydroxyl value 56.0 mg
KOH / g) 200 parts, tolylene diisocyanate (2.4-.2.6-
Urethane prepolymer with a free isocyanate group content of 3.72% by reacting 35.7 parts of isomer ratio 80:20) at 85 ° C for 60 minutes.
235.7 copies were obtained. 353.5 parts of a urethane prepolymer solvent solution prepared by adding 117.8 parts of dioxane to 2.6 parts of 98% H ₂ SO ₄ (0.75 equivalent of free isocyanate group) sodium bisulfite 16
2.3 parts (0.75 equivalent of free isocyanate group), water 30.3
50 parts in 284.9 parts of a mixed aqueous solution consisting of 235.7 parts of dioxane and 235.7 parts of dioxane
After slowly adding the mixture at 60 ° C over 60 minutes, the mixture was further reacted at 68 ° C for 30 minutes. After completion of the reaction, the temperature was cooled to 30 ° C., 15 parts of 35% hydrogen peroxide solution was added, and the reaction was continued for 120 minutes.

Then, after neutralizing with 29.5 parts of 40% aqueous potassium hydroxide solution, the produced neutralized salt was separated. The filtrate was desolvated to give a pale yellow, fluid viscous liquid.

The amine value of this product was 47.0 [mg-KOH / g], and the amine conversion rate was 92.4% based on the free isocyanate groups of the urethane prepolymer.

Example 1 As a polyol component, 100 parts of ricinoleic acid triglyceride (average hydroxyl value 180 mgKOH / g), 100 parts of talc, 2.5 parts of synthetic zeolite, 0.05 parts of dibutyltin dilaurate and 5.0 parts of pigment 5.0 were uniformly stirred and mixed to prepare a liquid A. . Next, crude MDI (NCO equivalent 136) was used as an isocyanate component, and this was designated as solution B.

Mix ratio of liquid A and liquid B (weight ratio is 4.55 / 1.00 (NCO to active hydrogen ratio 1.05), and the coating thickness is on the Teflon sheet.
It was sprayed using an airless spray so as to have a particle size of 300μ.

The crack-following property, moisture permeability, and chlorine permeability of the coating film film that had been cured in the room for 7 days were measured.

Next, 0.2 kg / m ² brush of Polyflex M-50 (one-component urethane primer; manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) was applied to the mortar board in advance, and after 3 hours at room temperature, the polyurethane resin was applied in the same manner as above. Was coated with a coating thickness of 300μ and a two-component acrylic urethane coating so that the coating thickness was 50μ, and alkali resistance and weather resistance were measured. The results are shown in Table 1.

Example 2 Instead of the liquids A and B of Example 1, poly BD R45HT was used in combination with castor oil polyol YX-410 (manufactured by Ito Oil Co., average hydroxyl value 166 mgKOH / g) as a polyol component, if necessary.
(Manufactured by ARCO. Average hydroxyl value 46.5 mg / KOHg) 90 parts of 50:50 mixture and urethanized polyamine (amine value)
47mgKOH / g) 10 parts, 100 parts of talc, 30 parts of xylene as a uniform mixture of liquid A, crude MD as the isocyanate component
24.2 parts of I (F-NCO31.0%) was used as the liquid B, and the other parts were coated by the two-head air spray in the same manner as in Example 1. At this time, the sum of the average hydroxyl value and amine value is 10
0.0 mg KOH / g, NCO to active hydrogen ratio is 1.0.

The results are shown in Table 1.

Comparative Examples 1 and 2 Commercial acrylic paints and tar epoxy paints were applied with the same coating thickness (350μ) as in Example 1, respectively.

The results are shown in Table 1.

The acrylic paint had poor crack followability and water permeability, and the tar epoxy paint had poor crack followability.

Comparative Example 3 Instead of the liquid A and the liquid B of Example 1, as a polyol component, a polyester polyol obtained by condensation of diethylene glycol and adipic acid (average hydroxyl value 25 mg KO
H / g) 100 parts, talc 100 parts, synthetic zeolite 2.5 parts, dibutyltin dilaurate 0.05 parts, ethyl acetate 50 parts and pigments
A homogeneous mixture of 5.0 was used as the liquid A, and a crude MDI (NCO equivalent of 136) as the liquid B was used as the isocyanate component. Others were the same as in the examples.

At this time, the ratio of NCO to active hydrogen is 1.00.

The results are shown in Table 1.

Comparative Example 4 Propylene oxide adduct of glycerin (average hydroxyl value
270mgKOH / g) 100 parts, talc 100 parts, synthetic zeolite 2.5
Part, 0.05 part of dibutyltin dilaurate and 5.0 parts of pigment were uniformly stirred and mixed to prepare a liquid A. As the isocyanate component, a 3 mol tolylene diisocyanate adduct of trimethylolpropane (F-NCO 13.2%) was used, and this was designated as solution B. Liquid A and liquid B were mixed so that their compounding ratio (weight ratio) was 1.36 / 1.00, and 10.0% methyl ethyl ketone was simultaneously added to and mixed with the resulting mixture, and the same as in Example 1 below. .

The average hydroxyl value at this time was 457.1 mg KOH as the sum of propylene oxide adduct of glycerin and trimethylolpropane.
/ g.

The NCO to active hydrogen ratio is 1.0.

The results are shown in Table 1.

Comparative Example 5 54.6 parts of an acetoxime block of isophorone diisocyanate, 40.4 parts of 12-hydroxystearic acid triglyceride, 5 parts of trimethylolpropane and 0.05 part of dibutyltin laurate were melt mixed at 100 ° C.

Pylon OI 1% and KBM403 (silane coupling agent; manufactured by Shin-Etsu Chemical Co., Ltd.) 3% were added to this resin composition, melt-mixed, and then coated on a Teflon sheet with an applicator to a coating thickness of 300μ. did.

It was cured at room temperature for 7 days, but the coating film was brittle and the physical properties could not be measured. It is considered that this is because the resin composition did not react and cure. Then, in the oven at 200 ℃, 15
It was baked for a minute and reaction-cured. The results are shown in Table 1.

Those using the block body of the polyisocyanate compound as a raw material from those results, crack followability, moisture permeability,
It was confirmed that the chlorine permeability was poor.

The coating film was aged at room temperature for 1 week and then subjected to the following tests.

"Appearance of coating film": According to JIS K 5400.

The uniformity, flow, unevenness, cracks, and peeling of the coating film were examined, and a good one was rated as ◯ and a bad one was rated as x.

"Crack followability": The coating film can be fixed on both ends of the coating film and can be reciprocated repeatedly at intervals of 0 to 2 mm.
Reciprocation is defined as 1 cycle. When the coating film does not break even after 100 cycles, it is marked with ◯, and when it breaks up to 100 cycles, it is marked with x.

"Moisture permeability"; according to ASTM E-96 (g / m ² .day).

"Chlorine permeability": Put a 3% saline solution on one side and distilled water on the other side in a water tank that can hold a coating film (70mm square on one side) in the middle, and measure the chlorine ion concentration in the distilled water by potentiometric titration. Then, the transmission amount Q is obtained by the following calculation.

V: Amount of distilled water in the water tank (g) m: Chloride ion measurement result (ppm) A: Area of the coating film in direct contact with the water surface (cm ² ) "Alkali resistance"; according to JIS K 5400.

Immerse the film in a saturated solution of calcium hydroxide for 30 days and check if there is any swelling, peeling or peeling. The ones that do not exist are marked with ○, and the ones that exist are marked with x.

Claims (1)

[Claims] 1. A polyurethane resin obtained by reacting a polyol and an organic polyisocyanate compound at an NCO to active hydrogen ratio of 0.60 to 1.50, wherein the polyol is ricinoleic acid ester polyol alone or a mixture of ricinoleic acid ester polyol and polyamine. And an average hydroxyl value of 30 to 45
0mgKOH / g, or the sum of average hydroxyl value and amine value is 30 to 45
A coating composition for a concrete or mortar structure, which is 0 mgKOH / g.