JPH04198285A - Aqueous emulsion coating material - Google Patents

Abstract

PURPOSE:To obtain the title coating material which gives a film having low CO2 permeability and high water vapor permeability and free from crazing by mixing a specified resin emulsion, diatomaceous earth, and a polyhydric alcohol or glycol ether at specified ratios. CONSTITUTION:The title coating material contains a vinyl acetate/acrylic copolymer resin emulsion or ethylene/vinyl acetate copolymer resin emulsion, diatomaceous earth, and a polyhydric alcohol or glycol ether (e.g. diethylene glycol monobutyl ether), wherein the amount of the diatomaceous earth is 50-150 pts.wt. based on 100 pts.wt. solids of the resin emulsion, the volume concentration of pigment including the diatomaceous earth is 30-50%, and the polyhydric alcohol or glycol ether accounts for 5-50wt.% of the volatile matter of the coating material.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a water-based emulsion paint for housing, which can be used, for example, as a paint for lightweight cellular concrete panels of unit housing.

[Background Art] In recent years, prefabricated unit houses have been constructed in which living rooms and the like that are the constituent parts of a house are manufactured as housing units in a factory, and these housing units are transported to a site and assembled. Lightweight aerated concrete panels are used for the wall panels and floor panels of such unit houses. This lightweight aerated concrete panel is manufactured by pouring a concrete slurry containing air bubbles into a mold, which is made mainly from cement and silica sand, and then steam-curing it in a high-volume, high-pressure autoclave. Ru. After manufacturing, the surface of the panel is coated with a water-based emulsion paint, and then forced dry at around 50°C.

Lightweight aerated concrete panels manufactured by autoclave curing have a large porosity and excellent moisture absorbing and releasing properties, so when used as interior wall panels for houses, they do not absorb moisture into the walls when the indoor relative humidity increases. absorb,
This has the advantage that when the humidity is low, moisture is released from within the walls, making it difficult for condensation to form on the walls.

On the other hand, inside a house, the carbon dioxide concentration is high due to exhalation, heating, cooking, etc. This carbon dioxide carbonates the lightweight cellular concrete panels, and as a result, a large amount of Problems may arise, such as (i) increased bulk density of the concrete panel and decreased porosity and reduced heat retention; (■) shrinkage of the material due to carbonation and drying shrinkage; This also causes cracks in the panel, etc.

Therefore, the paint used for surface painting of lightweight cellular concrete panels is required not only to not impede the water vapor absorbing and releasing properties of the lightweight cellular concrete panels, but also to have low carbon dioxide gas permeability.

Conventionally, water-based emulsion paints containing a pigment component containing diatomaceous earth at a high concentration near or higher than the critical pigment volume concentration have been used as paints satisfying these required characteristics.

[Problems to be Solved by the Invention] The above-mentioned conventional water-based emulsion paints have a problem in that, when applied thickly, the paint film tends to crack during forced drying.

The present invention has good moisture absorption properties and anti-carbonation properties,
Another object of the present invention is to provide a water-based emulsion paint that can prevent cracks in the paint film.

[Means and effects for solving the problems] The water-based emulsion paint according to the present invention contains a vinyl acetate-acrylic copolymer resin emulsion or an ethylene-vinyl acetate copolymer resin emulsion, diatomaceous earth, and polyhydric alcohols or glycol ethers (hereinafter referred to as , polyhydric alcohol, etc.), the content ratio of the diatomaceous earth is 50 to 150 parts by weight based on 100 parts by weight of the solid content of the resin emulsion, and the volume concentration of the pigment containing diatomaceous earth is 30 to 50%.
The composition is characterized in that the content of the polyhydric alcohol and the like is 5 to 50% by weight based on the volatile matter of the paint.

In the present invention, the vinyl acetate-acrylic copolymer resin emulsion or the ethylene-vinyl acetate copolymer resin! The combination of the emulsion and diatomaceous earth can impart favorable moisture permeability properties and particularly favorable anti-carbonation properties to the resulting coating film.

The diatomaceous earth used in the present invention is preferably sintered and porous.

If the content of diatomaceous earth is less than 50 parts by weight based on 100 parts by weight of the resin solid content of the resin emulsion, the carbonation prevention effect and moisture permeability will be poor;
If the amount exceeds 0 parts by weight, the viscosity of the coating material increases, resulting in poor coating workability, and disadvantages such as a decrease in the strength of the resulting coating film occur.

The pigment volume concentration (hereinafter referred to as PVC) is the volume ratio of diatomaceous earth in the coating film-forming components and pigments (coloring pigments and extender pigments) added as necessary. If this PvC is less than 30%, the moisture permeability of the resulting coating film will be poor, and if the PVC is greater than 50%, the moisture permeability will be excellent, but the strength of the coating film will be reduced.

Examples of polyhydric alcohols used in the present invention include ethylene glycol, propylene glycol, diethylene glycol, glycerin, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, and the like. I can do it.

The content of the polyhydric alcohol and the like is in the range of 5 to 50% by weight, preferably 10 to 30% by weight, and more preferably 20 to 25% by weight in the volatile matter of the emulsion paint.

If the content of the polyhydric alcohol or the like is less than 5% by weight in the volatile matter of the paint, it will not be effective in preventing cracks in the paint film. Also,
If it exceeds 50% by weight, it will have the effect of preventing cracks in the paint film, but the drying of the paint film will be too slow, resulting in poor workability, as well as flammability and reduced economic efficiency. It begins to occur.

In addition to the essential components such as the resin emulsion, diatomaceous earth, and polyhydric alcohol, the water-based emulsion paint of the present invention contains dispersants, antifoaming agents, preservatives, and thickeners that are commonly used as paint components. , additives such as film-forming aids are added as appropriate, and if necessary, coloring pigments and extender pigments are added to obtain a desired color tone. This mixture is then dispersed using a conventional paint dispersion machine.

The water-based emulsion paint of the present invention is applied by any method such as spray coating, roller coating, or brush coating. If this application amount is small, even if the dew condensation prevention effect is obtained,
Conversely, the carbonation prevention effect may be insufficient. Also,
If the amount is too high, there is a risk that dew condensation may occur even if the effect of preventing carbonation is obtained. Therefore, the appropriate application amount depends on the composition, but
It is preferably within the range of 300 to 1000 g/rrr.

The water-based emulsion paint of the present invention is suitably used for lightweight cellular concrete, and can also be applied to concrete, mortar, and other cement-based inorganic building materials that require prevention of carbonation.

[Example] Examples 1 and 2 Each component of resin emulsion, diatomaceous earth, diethylene glycol monobutyl ether, titanium dioxide (TiO7), calcium carbonate (CaCOs), additives, and water was mixed in the weight ratio shown below. A water-based emulsion paint according to the example was manufactured. However, in Example 1, vinyl acetate-acrylic copolymer resin emulsion [Movinyl 662 (trade name), Hoechst Synthesis (trade name)] was used as the resin emulsion.
In Example 2, an ethylene-vinyl acetate copolymer resin emulsion [Evadik EV-15 (trade name), manufactured by Dainippon Ink & Chemicals, Inc.] was used. This additive includes 2 parts by weight of a thickener (hydroxyethyl cellulose), a dispersant [Demol EP (trade name), Kao Atlas ■
[manufactured by] 3 parts by weight, antifoaming agent [Nopco 8034 (trade name),
(manufactured by San Nopco ■) A mixture of 5 parts by weight was used.

The PVC of the water-based emulsion paint in this example is 40
%, diethylene glycol monobutyl ether (
The content of DEC (abbreviated as DEC) in the volatile matter is 22% by weight.

Resin (solid content)...20wt% Tie, ...10wt% diatomaceous earth
...18wt% CaC0,-5wt% Additives ...2wt% Water ...35wt%DEG
...10wt% Dog 1ヱ1shiichi↓ Water-based emulsion paint according to each example with the same components and content ratio except that the content ratio of diethylene glycol monobutyl ether in the coating composition of Example 1 was changed. was manufactured.

The content of diethylene glycol monobutyl ether in the volatile matter was 5% by weight in Example 3 and 30% by weight in Example 4.

Comparative Example 1 A water-based emulsion paint according to Comparative Example 1 was produced using the same components and content ratios, except that the volatile content of diethylene glycol monobutyl ether in the paint of Example 1 was changed to 2% by weight.

Comparative Example 2 having the same components and content ratio as Example 1 above
A water-based emulsion paint according to Items 1 to 5 was manufactured.

However, as the resin emulsion, in Comparative Example 2, acrylic resin emulsion [Primal AC-22 (trade name),
Rohm & Haas Japan (stock system), Comparative Example 3
In Comparative Example 4, a styrene-acrylic copolymer resin emulsion [Acronal Y J-1650D (trade name), Mitsubishi Yuka Verdische (stock company)], and a vinyl acetate-vinyl versatate copolymer resin emulsion [Movinyl 801 (trade name), In Comparative Example 5, a vinyl acetate resin emulsion [Movinyl 116 (trade name) manufactured by Hoechst Synthesis (trade name)] was used.

Regarding the water-based emulsion paints according to Examples 1 to 4 and Comparative Examples 1 to 5, the crack prevention properties, carbonation degree, and moisture permeability of the coating films were evaluated by the following evaluation methods. The evaluation results are shown in Table 1 below. In addition, V, V, and A of Comparative Example 4 are as follows:
Abbreviation for vinyl versatate.

Crack prevention unit After applying the above water-based emulsion paint at a coating amount of 500 g/rd to the surface of a lightweight aerated concrete panel for residential use, it was force-dried under warm air at a wind speed of 2 m/sec and a temperature of 50°C, and the dry coating film was free from cracks. Observe the presence or absence of

Measuring method of carbonation degree a, a piece of lightweight aerated concrete in which carbonation has not progressed (
70 x 70 x 40 mm), one side (70 x 70 mm) of this concrete piece was coated with the water-based emulsion paints of Examples and Comparative Examples, and the other five sides were sealed with epoxy resin to prepare a specimen. The coating amount at this time is 500 g/m.

b. The moisture content of the specimen is balanced in a carbon dioxide-free atmosphere at a temperature of 20° C. and a relative humidity of 60%.

C0 temperature 20℃, relative humidity 60%, carbon dioxide concentration 10%
Place the specimen in the atmosphere and expose it for one week.

d. Take a section 1 to 2 cm from the coated surface of the specimen and measure the degree of carbonation. The method for measuring the degree of carbonation is as follows:
i. A method of thermally decomposing carbonates and quantifying the generated carbon dioxide gas by infrared absorption spectrometry, etc.; (2) X-ray diffraction method of measuring the intensity of diffraction lines of calcium carbonate; ii. Decomposing carbonates with hydrochloric acid Any of the following methods can be used, such as measuring the pressure increase due to the generated carbon dioxide gas using a mercury manometer.

A piece of lightweight aerated concrete (15X 15X 20m)
The water-based emulsion paints of Examples and Comparative Examples are applied to one side (15 x 15 mm) of the sample, and the other five sides are sealed with epoxy resin. The amount of application at this time is soog/bo.

b. Equilibrate the moisture content of the specimen in an atmosphere with a temperature of 20° C. and a relative humidity of 60%.

The specimen is placed in an atmosphere with a C0 temperature of 20° C. and a relative humidity of 90% and exposed for one week.

d. Measure the weight of the specimen over time, and measure moisture permeability from the change in weight.

Table-1 From this Table-1, according to the water-based emulsion paints according to Example 1, Example 2, and Example 3, vinyl acetate-acrylic copolymer resin emulsion (Example 1) or ethylene-
Since it contains vinyl acetate copolymer resin emulsion (Example 2), diatomaceous earth, and diethylene glycol monobutyl ether, it has excellent properties in terms of crack prevention, carbonation degree, and moisture permeability. Recognize.

Furthermore, according to the water-based emulsion paint according to Example 4,
Since the content of diethylene glycol monobutyl ether was relatively small, very few cracks occurred in the coating film, and the crack prevention effect could not be said to be perfect, but there was no problem in practical use.

On the other hand, according to the water-based emulsion paint according to Comparative Example 1, since the resin emulsion is acrylic and the content of diethylene glycol monobutyl ether is low, the degree of carbonation and moisture permeability are excellent; Cracks appeared in the membrane.

In addition, according to Comparative Examples 2 to 5, no cracking occurred in the coating film, but since the resin emulsion was not a vinyl acetate-acrylic copolymer resin emulsion or an ethylene-vinyl acetate copolymer resin emulsion, the degree of carbonation and moisture permeability At least one of the characteristics was poor.

Comparative Examples 6 to 8 Comparative Examples 6 to 8 contained the same components as in Example 1, but the weight ratio of resin, diatomaceous material, etc., and the ratio of PvC were changed as shown in Table 2 below. A water-based emulsion paint was produced, and its carbonation degree and moisture permeability were evaluated in the same manner as in the above examples. The results are shown in Table-2. In the composition in the table, DEC is diethylene glycol monobutyl ether.

Table 2 From Table 2, according to Comparative Example 6, the content ratio of diatomaceous earth is lower than the range specified in the present invention, so even though the carbonation prevention effect is obtained, the moisture permeability is poor. Also,
According to Comparative Example 7, since the content of diatomaceous earth is higher than the range specified in the present invention, both the carbonation prevention effect and moisture permeability are practically acceptable, but the strength of the coating film is weak.
It has the disadvantage of being brittle. According to Comparative Example 8, since the PVC is thick, even though the moisture permeability is good, the carbonation prevention effect is poor.

Therefore, when the water-based emulsion paint according to this example is used as an interior paint, a crack-free paint film can be formed. For this reason, when used in lightweight cellular concrete panels, for example, the permeability of carbon dioxide gas is low, so it is possible to suppress a decrease in porosity, an increase in drying shrinkage, and the occurrence of cracks that occur as carbonation progresses. In addition, because of its high water vapor permeability, there is no condensation on the wall surface even in winter or the rainy season, which is good in terms of hygiene, aesthetics, and durability.

In addition, when used as a paint for ordinary concrete, the carbonation of the concrete due to the progress of carbonation is suppressed, which causes the steel to rust and expand in volume, which can destroy the concrete itself. points can be resolved.

[Effects of the Invention] According to the present invention, cracks in the paint film when drying (
Moreover, since a water-based emulsion paint with low carbon dioxide permeability and high water vapor permeability can be obtained, it is useful as a paint for preventing carbonation and dew condensation of cement-based inorganic building materials.

Claims (1)

[Claims] (1) A vinyl acetate-acrylic copolymer resin emulsion or an ethylene-vinyl acetate copolymer resin emulsion, containing diatomaceous earth and a polyhydric alcohol or glycol ether, the content ratio of the diatomaceous earth being 100% by weight of the solid content of the resin emulsion. 50 to 150 parts by weight, and the pigment volume concentration containing diatomaceous earth is 30 to 50 parts by weight.
%, and the content of the polyhydric alcohol or glycol ether is 5 to 50% by weight based on the volatile matter of the paint.