JPS5930865A - Inorganic coating composition - Google Patents

Abstract

PURPOSE:To obtain titled composition capable of providing highly water and oil- repellent coating film of improved stain and water resistance, for use in coating the concrete for interior and exterior finishing material, by incorporating a fluoroplastic in a room temperature-curable inorganic silicate coating. CONSTITUTION:For example, (A) a fluoroplastic emulsion is first prepared by incorporating (i) water or an alkali silicate aqueous solution with (ii) 0.05- 20wt% of a fluoroplastic powder (pref. of a size of 100mu or smaller) (based on the solid of the component (B) described below), a surfactant, dispersant, etc. This emulsion is incorporated in (B) a room temperature-curable inorganic silicate coating with the curing agent consisting of at least one sort of compound selected from calcium sulfite, calcium thio-sulfate, and activated magnesium oxide, thus obtaining the objective coating composition. For the coating layer with a thickness of ca. 0.1mm. or lower, this composition should be singly applied, while in the case of thicker layer, a fluoroplastic-contg. coating will be used as a primer. EFFECT:Formulating process being easier than ever, providing gloss surface of good design. USE:For coating on the interior finishing material in underground passage.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to inorganic coating compositions. Many inorganic silicate-based paint compositions using an aqueous alkali silicate solution as a binder have been proposed, but most of them require heat treatment and are difficult to apply on-site when used for interior and exterior materials for general construction. There is a problem.

As room-temperature-curable inorganic paint compositions, there are known ones that use alkali silicate as a binder and calcium sulfite, calcium thiosulfate, calcium silicate, nofluminium compounds, etc. as hardening agents.
4285, JP-A No. 52-134367, etc.), and by changing the filler in various ways, it can be used for interior and exterior materials for general buildings, interior materials for barriers, underground passages, etc., and also as adhesives. Although this composition has excellent properties such as nonflammability, durability, chemical resistance, and mold resistance, it has the drawback that it is porous and water permeable, and therefore does not have sufficient stain resistance. In other words, when this material is used for painting as described above, unlike organic paints, it does not attract dust due to static electricity, but the paint film becomes dirty due to physical contamination. It may progress to the inside of the body. Usually, to prevent such contamination, metal powders such as calcium stearate and aluminum are added to the paint, or oil-based ingredients, water-based silicone, varnish, etc. are added to the paint layer, or K is added to the paint surface.
A method of fIi is being used. However, in either case, there are problems in terms of weather resistance and water resistance, and silicone water repellents are particularly unfavorable because they tend to easily attract dust and the like.

To solve the above problems, Kizataki has created an inorganic paint composition C, which is characterized by blending fluororesin powder into an inorganic silicate paint that cures at room temperature. . Inorganic silicate-based paints that harden at room temperature use silicic acid arunonori as a binder and calcium sulfite,
A paint containing one or more selected from calcium thiosulfate and activated magnesil oxide as a curing agent is used. Alkali silicates are preferably C 1 to silicates of alkali metals such as lithium, potassium, and lithium, and 5
The molar ratio of L02/MtO (M is an alkali metal) is 1.
5 to 4.5 aqueous solution (solid content concentration 10 to 50% by weight),
Or moisture 10 to 30% by weight preferably 15 to 25
An aqueous solution of a powdery alkali hydrated silicate containing % by weight can be used.Also, silica sol may be added to these. Among the hardening agents, magnesium oxide and C are iodine adsorbents with a maximum of 30 to 300 m< I ・l, /'G -11g
An activated version of 0 is used. In addition to these hardeners, auxiliary hardeners include C-M7J lucium, zinc oxide to improve strength, and aluminum hydroxide and alumina to reduce shrinkage and prevent cracks during hardening. , an aluminum compound such as hydrated alumino may be used in combination. The above amount of curing agent is suitably 10 to 300% by weight based on the solid content of the alkali silicate; if it is less than 10% by weight, curing failure occurs, adhesive strength and water resistance decrease, and efflorescence occurs. weight%
If it exceeds , the pot life will be significantly shortened and workability will deteriorate. In addition to the above ingredients, silica sand and clay are used as inorganic fillers.

Calcium carbonate, talc, bentonite, diatomite,
Kaolin, barley 1~. It is normal to mix shirasu balloons, vermiculite powder, glass peas, asbestos-resistant glass fibers (asbestos, alkali-resistant glass fibers H), etc., and the powder has an appropriate particle size and particle size valve hole depending on the application. Use 7. The blending amount of such an inorganic filler is 100 to 1000% by weight based on the solid content of the alkali silicate.

Examples of the fluororesin powder used in the present invention include polytetrafluoroethylene, polytrifluorochlorinated-■-tyrene, poly[
Examples include ethylene tetrafluoride-polypropyne hexafluoride J, polyvinylidene fluoride, polyvinyl fluoride, etc., and the particle size is 100 μm or less, preferably 50 μm or less C. Particle size is 10
If it exceeds 0μ, dispersion during mixing will be poor, and the uniform water repellency of the resulting coating film will be impaired.

There are two methods for blending fluororesin powder:

1) Prepare a fluororesin emulsion by adding fluororesin powder, a surfactant, a dispersant, etc. to water or an aqueous alkali silicate solution, and mix this directly into an inorganic silicate-based paint that cures at room temperature to coat the base. Apply.

11) An inorganic silicate-based paint that cures at room temperature is applied to the substrate in advance, and after curing, an inorganic silicate-based paint containing the above-mentioned fluororesin is overcoated.

In other words, when the thickness of the coating layer on the substrate is thin (approximately 0, 1
ml or less), the former method is advantageous, and when the coating layer is relatively thick (of the order of about 1 nm), the latter method is used as a surface layer and a thin coating (about 20 to 40 microns) of C fluororesin-containing paint is sufficient. Fluororesin powder has poor affinity with water, so even if it is added directly, it will not achieve uniform dispersion and will not exhibit its performance. The blended amount of fluororesin powder is +) U) Alkali silicate in either case.

0.0 based on the total solid content of curing agent and inorganic filler
A range of 5 to 20% by weight is suitable.

If it is less than 0.05% by weight, there is no effect of fluororesin compounding, and 2
When the weight exceeds 0, the agglomeration of the coating film becomes small and the mechanical strength decreases.

The fluororesin powder is uniformly dispersed in the inorganic coating composition thus obtained, and the resulting coating film obtained by applying this to a substrate has sufficient water and oil repellency. In other words, compared to conventional silicate-based inorganic paints that do not contain fluororesin powder, not only is stain resistance improved without the use of water repellents, but the porous surface is densified and water resistant. Sexuality is also improved. Furthermore, by polishing the surface of the coating film using a puff or the like, the surface of the coating film becomes smoother, and a glossy surface with a glossy design and an improved appearance not seen in conventional products can be obtained.

Blend m of fluororesin powder used in the coating composition of the present invention
Only a small amount is required, and the mixing method can be easily carried out without using organic solvents.It is especially suitable for large-scale painting work such as interior and exterior materials for buildings, interior materials for entranceways, underground passages, etc. Suitable for on-site construction. The base material C to be applied to the coating composition of the present invention includes various materials such as concrete, asbestos slate board, valve cement 1-board, PC board, AIC board 1-plywood, and metal board. When reusing the coating composition of the present invention, use any suitable coating method such as spraying, roller coating,
Trowel painting, machine painting, etc. can be used.

Hereinafter, the present invention will be described in detail with reference to examples. In each example, parts and percentages are respectively parts by weight and 1% by weight.

Examples 1-4. Comparative Example 1.2 [Manufacture of fluororesin emulsion] Fluororesin fine powder (particle size 40 to 50μ) was added to water or aqueous alkali silicate solution (solid content 30%) in proportions not shown in Table 1.
Added 0.4 part of surfactant and 0.1 part of emulsifier7
A slurry liquid to which 0.2 part of a dispersant was added was placed in a ball mill and mixed for 4 to 5 hours to prepare a -C fluororesin emulsion.

[Manufacture and application of paint] A curing agent, a filler, and a pigment having the composition shown in Table 1 were mixed for 20 minutes using a Henschel mixer to prepare a curing composition. Add to this an aqueous alkali silicate solution (solid content 30%)
The fluororesin emulsion prepared by the above method was added and kneaded for 2 minutes using a lab mixer r to obtain an inorganic coating composition. This paint composition is 41! The material was coated on an asbestos board with a thickness of I to a coating layer thickness of approximately 0.2 nm, and the physical properties of the coating film were measured after curing at room temperature.

For comparison, the physical properties of the coating film after curing at room temperature were measured in the same manner except that the fluororesin emulsion was not added.

Table 1 (Composition is in parts by weight) Notes (1) Example 3 uses poly[tetrafluoroethylene-hexafluoropropylene 1, and the others use polytetrafluoroethylene (2) Iodine adsorption fJ, 200''+9- 1/g
・flg.

The physical properties of the coating film were measured by the following method.

1) Water repellency According to JI S P 8137, the tip of the buret containing distilled water is separated from the test piece by 10 CI in the vertical direction, and the length is 3 so that the water droplet can flow down on the test piece maintaining an inclination of 45°.
Adjust so that it becomes 00 *v. Pour one drop of water from the burette and observe the traces of the water drop.

Evaluation Ro: A continuous trace with a uniform width R4: A continuous trace with breaks here and there, clearly showing a width narrower than a water drop R Day: Half of the trace R7: 1/4 of the mark is long and wet due to water droplets 11) Water-permeable treatment: 3 days old, with a diameter 75.0 funnel on the surface and a height of 2
The water permeability was measured after the water column of 5 On was left standing for 124 hours.

iii) Stain resistance The painted boards (900 x 900 u) of each example and comparative example were exposed in a staircase for 5 months, and the degree of contamination was determined! ! It was measured using α degree.

Contamination degree -10-1+ [p Recovery rate -L2 / LO Lo...Illuminance immediately after installation...Illuminance after exposure L2...Illuminance after washing +v > 2 Oil-based 1) h law enforcement standards Use Machine Tears 1 instead of hot distilled water. The evaluation is similar.

Applicant: Osaka Soda Co., Ltd. Agent: Patent Attorney Toru Shijo

Claims (4)

[Claims] (1) An inorganic paint composition characterized by blending a fluororesin powder into an inorganic citrate-based paint that cures at room temperature. (2) The curing agent for the room temperature curable inorganic silicate paint is calcium sulfite-9calcium thiosulfate. The coating composition according to claim 1, which is one or more selected from activated magnesium oxides. (3) The $Iwagumi paraboloid according to claim 1 or 2, wherein the fluororesin powder has a particle size of 100 μm or less. (4) The blending amount of the fluororesin powder is 0.05 to 20% by weight based on the solid content of the room temperature curable inorganic silicate paint. The coating composition described in .