JPS62105983A - Manufacture of inorganic dressing board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing an inorganic decorative board, and particularly relates to a method for producing an inorganic decorative board that provides a good coating film.

Conventional technology and its problems In recent years, there has been a battle for mineralization of interior materials, partition materials, ceiling panels, etc.*tC
ノ, JJ amount; [Ding 1-Le ↓ Upu 艷-2) - Singing - J・-
・E-No organic decorative board is made by applying an inorganic paint to the surface of an inorganic material to form a film, and has excellent nonflammability.

It has excellent water resistance, chemical resistance, and dimensional stability as well as good coating performance.However, the conventional i+
Decorative boards with a positive texture are heavy and have poor machinability, so their uses have been limited. Therefore, in order to reduce the weight and improve the workability of f[lt textured makeup, it has been proposed to apply an inorganic paint to an inorganic base material that has toughness and good workability.

However, when an inorganic paint is applied to this type of inorganic base, there is a problem in that the paint is sucked in and a good paint film cannot be formed. JP-A No. 55-51780 discloses undercoating with an aqueous lithium silicate solution.The method J described above is certainly effective in preventing uneven suction of the -L paint, but this Experiments conducted prior to the present invention revealed that decorative laminates produce large racks during boiling water resistance tests. On the other hand, when a sodium silicate or potassium silicate aqueous solution having high adhesion is used, there is a problem that chemical resistance and efflorescence resistance are poor.

Structure of the Invention In view of the above-mentioned problems, the present inventor conducted intensive research on improving the coating performance of inorganic substrates, and found that when a lithium-containing alkali metal silicate aqueous solution is applied to the surface of an inorganic substrate, it becomes denser. It was discovered that a coated surface with good adhesiveness could be formed using the method, and based on this knowledge, the method of the present invention was completed.

That is, the gist of the method of the present invention is that the surface of the inorganic base material is coated with the general formula R, O-+llLi, 0-nsiot (wherein R represents sodium or potassium, m is 0.1≦m<3,
n is 4≦n<10. ) After applying a lithium-containing alkali metal silicate aqueous solution as an undercoat, an inorganic paint mainly composed of an alkali metal silicate is applied as an overcoat, and the process is heated and cured.

Inorganic base materials in the present invention include asbestos slate boards,
Valve mixed asbestos cement board, slag gypsum board.

Examples include cement calcium silicate board, extruded asbestos cement calcium silicate board, etc. From the viewpoint of cutting workability and handling properties, the specific gravity is preferably 10 or more, preferably about 1.5 to 1.9.

Regarding the molar ratio of the lithium-containing alkali metal silicate, when the lithium content is low (m<0.1), the chemical resistance and efflorescence resistance of the coating film decreases, and when the lithium content is high (l≧3), the coating film deteriorates. It is undesirable because the boiling water resistance of Furthermore, when n<4 with a small warpage uniformity, the chemical resistance of the coating film is
Efflorescence resistance decreases, and when n>10, boiling water resistance decreases, which is not preferable.

The lithium-containing alkali metal silicate aqueous solution is 5 m
Preferably, the solids content ranges from m% to 20% by weight. This is because if the solid content is less than 5% by weight, the amount of evaporated water is large and it is difficult to form a dense film, and if it exceeds 20% by weight, whitening and foaming occur, making it impossible to form a smooth coating.

The inorganic paint mainly composed of alkali metal silicate in the method of the present invention has an inorganic binder of 10% on a dry basis.
~35% by weight, up to 40% by weight of curing agent, and 25-90% by weight of pigment and/or filler.

As the inorganic binder, water-soluble alkali metal silicate compounds such as sodium silicate, potassium silicate, lithium silicate, and modified products thereof are used.

Hardening agents are added to impart water resistance, and are usually oxides of divalent metals such as zinc oxide, ortho- and condensed phosphates of polyvalent metals such as carunium, aluminum, and aliphatic acids. Salts and the like can be used alone, mixed or fired.

Pigments are added to color the paint film, and fillers are added to balance the composition of the paint and prevent foaming, cracking, etc. However, from the viewpoint of paint stability 1 workability, they are added to binder components at room temperature. is preferably one that hardly reacts, especially one that does not substantially react. As the pigment, for example, an oxide of a transition metal such as chromium oxide, iron oxide, titanium oxide, or manganese dioxide or a composite oxide containing a transition metal is used, and as a filler, for example, alumina or quartz is used.

Zirconia, zircon, mullite, glass powder, etc. are used.

If these constituents deviate from the above ratios, it is usually difficult to obtain a good coating film.

For inorganic paints, each component is processed using a ball mill, attritor, vibration mill, or homogenizer. Colloid mill.

Although it is prepared by mixing and dispersing using a stirrer or the like, it is preferable that the dispersion be as uniform as possible, and the presence of coarse particles or coarse gels often causes non-uniformity. Preferably, it is necessary that substantially no particles with a diameter of 20 μm or less are present, and if possible, measures such as removing aggregated particles with a sieve are added. The viscosity of the paint is approximately 400~
A range of 2000 cp is preferable. In addition, there is a thickener in the paint.

It is possible to use auxiliary agents such as dispersants; for example, sodium alginate is effective as a thickener.

When undercoating the aqueous lithium-containing alkali gold silicate solution described above on the inorganic base material, inorganic bamboo chips (heated to a surface temperature of 60°C or higher in advance) with a solid content of 5 weight 3 to 5% of the 11% aqueous solution
It is preferable to apply at a rate of 0 g/m' (wet weight).

This is because the water in the aqueous solution evaporates quickly if it is heated in advance, and the application amount is 3 to 50 g.
/m” because the coating film made from this aqueous solution has a thickness of several μm.
This is because a sufficient amount of suction prevention function can be achieved.

The method of topcoating an inorganic paint is to apply an undercoat with the aqueous solution, and then apply 50 to 500 g of an inorganic paint mainly composed of an alkali metal silicate adjusted to have a solid cedar content of approximately 50 to 70%.
Apply at a rate of m'' (wet weight).

In particular, in this two-coating method, it is preferable to apply the inorganic paint before the surface of the inorganic base material cools and the surface temperature decreases. This is mainly because the water in the inorganic paint that falls onto the surface of the paint film formed by the lithium-containing alkali metal silicate aqueous liquid is evaporated by the heat of the substrate, and the pressure is used to further prevent suction. .

1+++ Thermal curing involves raising the temperature in stages from the inlet temperature after 100°C (0), and holding the coated inorganic base material at 270°C or higher for a certain period of time in a heating furnace. This is done by

Example i 50 parts by weight of No. 3 water glass, 5 parts by weight of aluminum phosphate 1'7m, 5 parts by weight zinc oxide, m parts titanium oxide 7°5 balls,
1 part of titanium-based Buddhist pigment 5 parts, quartz powder (2 μm) 12.
5 parts by weight and 15 parts by weight of water were mixed in a ball mill for 30 minutes t-1, and then passed through a 200 mesh sieve to prepare an inorganic coating composition having a solid content of about 60% and a viscosity of about 850 Cp. According to the grind gauge, almost no particles of 20 μm or larger were observed in this paint.

On the other hand, an inorganic base material consisting of an asbestos cement board containing bulbs with a specific gravity of 1.8 was used, and its surface was heated to 130°C.
After heating to , the solid content was 13% by weight and 9%, m=o. 3. n=5
30 g/m of lithium-containing alkali metal silicate aqueous liquid was sprayed with an air spray gun (pressure 3, 5 kg/cm2).
Apply at a rate of m2. Immediately after this, apply 15% of the inorganic paint with an air spray gun of about 60% by weight solids.
It was applied at a rate of 0g/m'' (wet weight) and cured by heating in a heating furnace at 270°C for 10 minutes.The heating furnace was set to have an inlet temperature of 100°C and gradually increase the temperature to higher temperatures. It is.

Example 2 After applying the lithium-containing alkali metal silicate aqueous solution in Example [2], the surface temperature was left to cool to 50° C., and the same procedure was performed thereafter to obtain a sample.

Comparative Example 1 A sample was obtained by performing the same operation as in Example 1 without applying the lithium-containing alkali metal silicate aqueous solution to the same inorganic base material as in Example 1.

Comparative Example 2 (Invention described in JP-A-55-51780) Example 1
After heating the same inorganic material (O) to 130°C, a lithium silicate aqueous solution (solid content 2.2%, SiO*/Li
Undercoat 1-1 with tO=4.5) at a rate of 60g/1m"
Thereafter, the same operation as in Example 1 was carried out to obtain a sample.

Comparative Example 3 A commercially available mineralized plate (product name: Toshi Grasal) with a specific gravity of 2.0 was used as a sample.

Each sample obtained as described above had -] cracks,
The unevenness, machinability, and boiling water resistance were observed and measured. The results are shown in Table 1.

Table 1 shows the cracks observed under magnification (magnification = 30) with a magnifying glass.

The unevenness of luster is shown when visually observed.

The machinability is determined by visually observing the presence or absence of chipping at the peripheral ridge when cutting with a hand-tipped saw.

Boiling water resistance indicates the case where the surface of the coating film was observed with a magnifying glass (magnification: 30) after being immersed in boiling water for 45 minutes.

As is clear from Table 1, Examples 1 and 2, which are inorganic decorative boards according to the present invention, have a coating film similar to Comparative Example 1, which was formed without applying a lithium-containing alkali metal silicate aqueous solution. Comparative Example 2, which had no cracks or unevenness on the surface and was undercoated with an aqueous solution of sodium silicate.
As shown in the figure, there were no cracks in the boiling water test, indicating that the film had excellent coating performance.

Furthermore, when cut with a hand-tipped saw, in Comparative Example 3, which is a commercially available inorganic decorative board, chips occur at the peripheral ridges 1 to b. This shows that Examples 1 and 2 have better machinability than Comparative Example 3.

Effects of the Invention As described above, according to the detailed method of the present invention, since the lithium-containing alkali metal silicate aqueous solution is viscous, there is very little suction, and a coating film can be formed by medium-dip application, resulting in a decrease in the substrate surface temperature. There are also few. The coating formed by undercoating this aqueous solution is dense and highly adhesive. This prevents inorganic paint from being sucked in, making it possible to form a paint film on porous inorganic substrates, which previously could not be formed by sucking inorganic paint, and also prevent the formation of cracks, crater-like pores, and uneven gloss. Therefore, good coating film performance can be obtained.

As a result, an inorganic decorative board having excellent heat resistance, boiling water resistance, scratch resistance, and abrasion resistance can be obtained.

In particular, if the method of the present invention is applied to valve-mixed asbestos cement, it is possible to form a good coating film, and since the pulp part has a lower specific gravity and toughness than other mixtures, it is possible to reduce the weight and , impact resistance and machinability can be improved.

Therefore, during cutting, no chipping occurs on the peripheral edges, and workability in on-site construction is significantly improved, making it possible to expand the range of uses.

Furthermore, the adhesion of the coating film surface by the lithium-containing alkali metal silicate aqueous solution improves the adhesion of the inorganic paint, so that the coating film is less prone to cracking or peeling even after the coating film is formed.

Claims (1)

[Claims] (1) General formula R_2O・mLi_2 on the surface of the inorganic base material
O.nSiO_2 [wherein R represents sodium or potassium, m is 0.1≦m<3, and n is 4≦n<10. ] A method for producing an inorganic decorative board, which comprises undercoating with a lithium-containing alkali metal silicate aqueous solution represented by the following formula, then overcoating with an inorganic paint mainly composed of an alkali metal silicate, and curing by heating.