JPH0711189A - Board coating method - Google Patents

Abstract

(57) [Abstract] [Objective] The present invention provides a polyurethane one-part composition having rapid strength development, crack followability, high elasticity, and excellent durability, and a substrate which enables efficient curing promotion. To provide a coating method. According to the method of coating a substrate of the present invention, a polyurethane one-component composition is applied onto a substrate and cured to coat the substrate. A polyurethane one-component composition comprising a urethane prepolymer having two or more groups and (b) a one-component polyurethane composition comprising a compound having two or more oxazolidine rings in a molecule, and applied before curing , Water, hot water or hot steam.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a base coating method, more specifically, roof waterproofing, civil engineering waterproofing, floor / sidewalk, various sports fields, athletic fields, tennis courts, golf course paths. The present invention relates to a coating method of a base used for construction of a road surface such as.

[0002]

2. Description of the Related Art Conventionally, as a one-component polyurethane composition used for coating a substrate, for example, a composition containing a urethane prepolymer containing a terminal isocyanate group as a main component, or an enamine or urethane prepolymer is used. Mixtures containing block amines such as aldimine are known, but all of them have a reaction mechanism of curing by reacting with moisture (humidity) in the air, so that the skin of the coating film surface is relatively fast. When applied thickly, the lower part of the coating film is slow to cure, especially at low temperatures such as in winter, it does not cure even after 2 to 3 days after coating, and it does not work on the coating film and the next step work cannot be done There were drawbacks such as lengthening. Further, there is a method of blending a curing accelerating catalyst, but this has the disadvantage that it is meaningless to be a one-part type, and that the blending of a catalyst causes discoloration of the coating film and heat deterioration.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a base coating method for solving the above problems.

[0004]

A method for coating a substrate according to the present invention is a method for coating a polyurethane one-component composition by coating a polyurethane one-component composition on a substrate and curing the composition to form a polyurethane one-component composition. (A) A urethane prepolymer having two or more isocyanate groups at the end (hereinafter, also referred to as urethane prepolymer) and (b) a compound having two or more oxazolidine rings in the molecule (hereinafter, also referred to as an oxazolidine ring-containing compound) The purpose of the present invention is to treat the polyurethane one-component composition consisting of the above (1), which is applied before curing, with water, warm water or hot steam.

Examples of the substrate in the present invention include substrates made of cement concrete, asphalt concrete, stone, brick, glass, wood, synthetic resin, iron plate, stainless steel and the like. Further, if necessary, these substrates are preferably treated with a primer such as one-component moisture-curable urethane or epoxy resin.

Next, as the urethane prepolymer constituting the one-component polyurethane composition to be coated on the substrate, a polyoxyalkylene mono- and / or polyol and an organic polyisocyanate compound are reacted with each other to form a molecular terminal. Examples thereof include those having two or more free isocyanate groups.

Examples of polyoxyalkylene monools and polyols include monools such as methanol, ethanol, propanol, butanol, octanol and lauryl alcohol; ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol. Diols such as 1,6-hexanediol;
Polyols such as glycerin, trimethylolpropane, pentaerythritol, etc .; other than mono-, di- or triethanolamine, diglycerin, sorbitol, sucrose, etc., alone or in a mixture, ethylene oxide, propylene oxide or butylene oxide, alone or in a known manner. Examples thereof include compounds that are used in combination for addition polymerization.

Examples of the organic polyisocyanate compound to be reacted with the polyoxyalkylene monool and / or the polyol include diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate,
Liquid diphenylmethane diisocyanate, tolylene diisocyanate, tolidine diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate,
Examples thereof include tetramethyl xylylene diisocyanate, isophorone diisocyanate, naphthalene diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated diphenylmethane diisocyanate, etc., alone or in a mixture, or a buret body, an isocyanurate body or a carbodiimide modified product.

In the urethane prepolymer, the NOL / OH equivalent ratio of the monool and / or polyol and the organic polyisocyanate compound is 1.5 to 100, preferably 1.
It can be obtained by reacting in the range of 9 to 50 by a known method. In the case of the reaction between the monool and the organic polyisocyanate compound, the number of isocyanate groups in the organic polyisocyanate compound is 3 or more in the molecule.

Next, as a compound having two or more oxazolidine rings in the molecule, which is another component constituting the one-component polyurethane composition, N-hydroxyalkyl-oxazolidine and an organic polyisocyanate compound are used. Examples thereof include a reaction product, an esterified product of N-hydroxyalkyl-oxazolidine and a polycarboxylic acid, or a transesterified product of a polycarboxylic acid ester.

N-hydroxyalkyl-oxazolidine is a compound obtained by condensation reaction of aldehydes such as formaldehyde, acetaldehyde, propylaldehyde, butyraldehyde and benzaldehyde with dihydroxyalkylamines such as diethanolamine and dipropanolamine. Is.

The organic polyisocyanate compound is the above-mentioned organic polyisocyanate compound or the like.

Examples of the polycarboxylic acid include oxalic acid, malonic acid, succinic acid, methylmalonic acid, isosuccinic acid, glutaric acid, adipic acid, itaconic acid, maleic acid, fumaric acid, phthalic acid, terephthalic acid and isophthalic acid. , Tetrachlorophthalic acid, mellitic acid, pyromellitic acid and the like.

The reaction ratios of these are, for example, N-
1 mol of an organic polyisocyanate compound or 1 mol of a polycarboxylic acid based on 2 mol of hydroxyalkyl-oxazolidine
Molar or N-hydroxyalkyl-oxazolidine 3
For example, 1 mol of the organic polyisocyanate compound is used per mol.

The compounding amount of the urethane prepolymer and the compound having an oxazolidine ring is preferably 1 to 100 parts by weight of the compound having an oxazolidine ring with respect to 100 parts by weight of the urethane prepolymer. When the amount of the compound having an oxazolidine ring exceeds 100 parts by weight, the resulting urethane resin composition is soft and has poor water resistance. on the other hand,
When the amount of the compound having an oxazolidine ring is less than 1 part by weight,
There is no effect of preventing blistering of the coating film.

In the polyurethane one-component composition of the present invention, if necessary, an organic-treated inorganic filler, an inorganic filler, an organic filler, a solvent, a catalyst, a viscosity reducing agent, a plasticizer, a pigment,
Colorants, extenders, stabilizers, flame retardants, thixotropic agents, surfactants, inorganic fillers, urethane chips, rubber chips and the like can be used in combination.

Particularly, as the organic substance-treated inorganic filler,
For example, fatty acid-treated calcium carbonate, fatty acid metal salt-treated calcium carbonate, fatty acid ester-treated calcium carbonate,
Rosin acid treated calcium carbonate, resin acid treated calcium carbonate, fatty acid treated talc, fatty acid metal salt treated talc, fatty acid ester treated talc, fatty acid treated bentonite, fatty acid ester treated bentonite, phosphate ester treated calcium carbonate, silane treated calcium carbonate, titanium treated Examples thereof include calcium carbonate, surfactant-treated calcium carbonate, polyacrylic acid-treated calcium carbonate, fatty acid-treated silica, and fatty acid ester-treated silica.

The coating of the polyurethane one-component composition is carried out by using a gold iron, a wooden iron, a rubber rake, a roller or the like, but it can also be sprayed by a spraying machine.

Next, in the present invention, the polyurethane one-component composition coated as described above is treated with water, hot water or hot steam before curing. The treatment is carried out with water having a temperature of 0 to 120 ° C., hot water or hot steam at a pressure of 0 to 50 kg / cm ² and an amount of discharged water of 1 to 2.
It is sprayed at 0 liter / min with a spraying machine such as a water spray nozzle or a sprayer, but if necessary, spraying in a mist state is preferred. It should be noted that a humectant such as ethylene glycol or glycerin, a water retention agent, and a surfactant may be added to the water, warm water, hot steam or the like.

Further, in the present invention, a finishing material may be applied on the coating film obtained by curing the one-component polyurethane composition. Examples of the finishing material include water-based acrylic, water-based ethylene vinyl acetate, acrylic urethane, acrylic silicone, fluorine, acrylic, and other paints. Further, the one-component polyurethane composition may be flow-coated with a non-woven fabric, a woven fabric, a rope-like fabric, a net, paper or a bituminized product thereof as a core material.

[0021]

According to the method of the present invention, the one-component polyurethane composition is one which is naturally cured by moisture in the air, but by treatment with water, warm water or hot steam, the oxazolidine compound of Hydrolysis is promoted, and the generated secondary amino group and hydroxyl group immediately act as a curing agent for the urethane prepolymer, so that rubber elasticity develops quickly. Furthermore, if the water evaporates quickly like in summer,
When used in combination with a water retention agent, it is more effective because it prevents the water vaporization.

[0022]

EXAMPLES Hereinafter, the embodiments and effects of the present invention will be described with reference to examples, but the examples are merely for explanation,
It is not intended to limit or limit the spirit of the invention.

Example 1. In a planetary mixer, 100 parts by weight of lauric acid-treated calcium carbonate as an organic-treated inorganic filler, and 30 parts by weight of dioctyl phthalate.
Titanium oxide (20 parts by weight) and carbon (0.1 parts by weight) were added, and the mixture was kneaded at room temperature for 15 minutes, and subsequently, the mixture was kneaded at 100 ° C., and dehydration operation was performed in vacuum for 1 hour.

Next, polyoxypropylene / polyoxyethylene glycol (average molecular weight 2000, oxyethylene chain content 20% by weight) and polyoxypropylene / polyoxyethylene triol (average molecular weight 4000, oxyethylene chain content 20% by weight) were added. A urethane prepolymer I containing a terminal NCO group (containing a terminal NCO group) was obtained by mixing the mixture in a weight ratio of 2: 1 and reacting the mixture with 2,4 tolylene diisocyanate at an NCO / OH equivalent ratio = 2.1. 100 parts by weight of 100% by weight, obtained by reacting an equivalent molar amount of diethylanolamine and propylaldehyde
(2-Ethyl-1.3-oxazolidin-3-yl)-
10.6 parts by weight of an oxazolidine compound obtained by reacting 2 mol of ethanol with 1 mol of tolylene diisocyanate,
And 10 parts by weight of xylene were mixed into the kneaded product in the planetary mixer and kneaded at room temperature for 15 minutes to obtain a polyurethane one-component composition.

0.2 kg / m ² of urethane primer was coated on the roof of a concrete building, and after 30 minutes, a polyester non-woven fabric (unit weight of 50 g / m ² ) was applied as a reinforcing material, and immediately after the polyurethane one-component composition 1. 5 kg /
m ² was painted with a roller. The temperature during coating was 20 ° C and the humidity was 45%.

Immediately after coating, 0.1 kg of a 2% by weight aqueous solution of ethylene glycol was applied with a sprayer at a pressure of ² kg / m ^2.
The coating was sprayed at a rate of / m ² . Next, the tack free time was evaluated according to JIS-A5758, the possible riding time was evaluated according to actual walking, and the mechanical characteristics were evaluated according to JIS-K6301. The mechanical properties used were the same as those described above on release paper (the same applies below).
The results are shown in Table 1.

Comparative Example 1. In Example 1, the spraying of the ethylene glycol 2% by weight aqueous solution was not performed with the atomizer, and the other operations were performed in the same manner as in Example 1. The results are shown in Table 1.

Example 2. In Example 1, in place of the lauric acid-treated calcium carbonate of the organic matter-treated inorganic filler, calcium palmitate-treated calcium carbonate was used, and the urethane prepolymer I was replaced with polyoxypropylene glycol / polyoxyethylene glycol (average molecular weight of 200).
0, oxyethylene chain content 10% by weight) and diphenylmethane diisocyanate were reacted at an NCO / OH equivalent ratio = 2.2 to replace urethane prepolymer II with 11.5 parts by weight of the oxazolidine compound of Example 1 and use diethano. -6.3 parts by weight of a reaction product of 2-mol of 2- (2-propyl-1.3-oxazolidin-3-yl) -ethanol and 1 mol of hexamethylene diisocyanate, obtained by reacting butanol with an equimolar amount of 2-amine. The same procedure as in Example 1 was performed except that each was used. Further, in the same manner as in Example 1, the tack free time, the possible riding time and the mechanical characteristics were evaluated. The results are shown in Table 1.

Comparative Example 2. In Example 2, the spraying of a 2% by weight aqueous solution of ethylene glycol was not performed, and the other operations were performed in the same manner as in Example 2. The results are shown in Table 1.

Example 3. In a planetary mixer, 180 parts by weight of dioctyl phthalate, 200 parts by weight of lauric acid-treated calcium carbonate, 50 parts by weight of titanium oxide,
Carbon (0.3 parts by weight) and antioxidant (10 parts by weight) were added, and the mixture was kneaded at room temperature for 10 minutes, and subsequently, at 100 ° C., dehydration operation was performed for 1 hour under vacuum.

Next, polyoxypropylene / polyoxyethylene glycol (average molecular weight 2000, oxyethylene chain content 20% by weight) and polyoxypropylene triol (average molecular weight 3000) were mixed at a weight ratio of 2: 1 and Urethane prepolymer obtained by reacting mixture with 2,4 tolylene diisocyanate at NCO / OH equivalent ratio = 2.6 (terminal NCO group content rate: 5.5% by weight)
2- (2-Ethyl-1.3-) obtained by reacting 100 parts by weight of diethylamine with equimolar amount of propylaldehyde.
14.0 parts by weight of an esterified product of 2 mol of oxazolidin-3-yl) -ethanol and 1 mol of adipic acid was mixed into the kneaded product in the planetary mixer, and kneaded in a vacuum at room temperature for 15 minutes to prepare a polyurethane. A one-part composition was obtained.

[0032] After the urethane primer in a concrete floor 0.3 kg / m ² was coated, the 3 hours after the polyurethane one-component composition was 2.0 kg / m ² coating was spray immediately water mister, performed Evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 3. In Example 3, the mist spraying of water was not performed, and the other operations were performed in the same manner as in Example 3. The results are shown in Table 1.

Example 4. In a planetary mixer, 100 parts by weight of lauric acid-treated calcium carbonate as an organic-treated inorganic filler, and 30 parts by weight of dioctyl phthalate.
20 parts by weight of titanium oxide and 0.1 part by weight of carbon were charged, and the mixture was kneaded at room temperature for 15 minutes, and subsequently, at 100 ° C., dehydration operation was performed for 1 hour under vacuum.

Next, 100 parts by weight of polyoxypropylene polyol (average molecular weight 3000) / tolylene diisocyanate urethane prepolymer (terminal NCO group content = 3.7% by weight) and diethyl alcohol are mixed with propyl aldehyde in an equimolar amount. 2- (2-Ethyl-obtained by reaction
12.7 parts by weight of trioxazolidine obtained from 3 mol of 3-oxazolidin-3-yl) -ethanol and 1 mol of buretized hexamethylene diisocyanate, and 10 parts by weight of xylene were mixed into the kneaded product in the planetary mixer. The mixture was kneaded at room temperature for 15 minutes to obtain a one-component polyurethane composition.

Next, 0.2 kg / m ² of urethane primer was coated on the roof of a concrete building, and after 30 minutes, a polyester non-woven fabric (weight per unit area of 50 g / m ² ) was applied and immediately the above polyurethane one-pack composition was applied. 1.5 kg
/ M ² was coated with a roller. The temperature during painting is 20 ℃,
The humidity was 45%.

Immediately after coating, 0.1 kg of a 2% by weight aqueous solution of ethylene glycol was applied with a sprayer at a pressure of ² kg / m ^2.
The coating was sprayed at a rate of / m ² . Next, the tack free time was evaluated according to JIS-A5758, the possible riding time was evaluated according to actual walking, and the mechanical characteristics were evaluated according to JIS-K6301. The results are shown in Table 1.

Comparative Example 4. In Example 4, the spraying of a 2% by weight aqueous solution of ethylene glycol was not performed, and the other operations were performed in the same manner as in Example 4. The results are shown in Table 1.

[0039]

[Table 1]

[0040]

According to the coating method of the present invention, the curing is not promoted by mixing a reaction accelerating catalyst and the like, but the curing can be efficiently promoted by a simple operation such as spraying. Under the conditions of the temperature of 50 ° C. and the humidity of 50% or less, the curing time, which has conventionally required 48 hours or more, develops strength early and is completed in 2 to 5 hours. Therefore, it can be applied to waterproof materials, flooring materials, paving materials, etc., because labor shortages and construction periods can be eliminated.

Claims (1)

[Claims] 1. A urethane prepolymer having two or more isocyanate groups at the terminal (a) as a polyurethane one-component composition when a substrate is coated with a one-component polyurethane composition and cured to coat the substrate. And (b)
A polyurethane one-component composition comprising a compound having two or more oxazolidine rings in a molecule is used, and the polyurethane one-component composition coated before curing is treated with water, hot water or hot steam. And the base coating method.