JP3201660B2 - Base treatment method for porous inorganic material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of treating a porous inorganic material with a water-based resin which is excellent in prevention of air pollution, improvement in workability of painting, and excellent adhesion of a decorative coating film and freeze-thaw resistance.

[0002]

2. Description of the Related Art First, the background of technical development will be described. Generally, there are various types of porous inorganic materials such as asbestos and asbestos-free slate plates, calcium silicate plates, and gypsum-based inorganic plates. These substrates are porous and brittle, have a surface that can be easily removed in powder form, and have a characteristic that an alkaline substance is easily dissolved and eluted on the surface to be coated because it is a basic substance. However, if these properties are applied to a porous inorganic material with a decorative paint without a base treatment, the paint film will be peeled off when the curing tape is removed or with water penetration or freeze-thaw over time, and furthermore, the paint film surface It is a whitening phenomenon due to the efflorescence generated by dissolution and elution of the alkali substance in the material, and causes deterioration of the coating film such as remarkably impairing the appearance of the coating film.

[0003] For this reason, there has been known an undercoating method in which a solvent-based two-pack type epoxy resin or a solvent-based isocyanate prepolymer is diluted and impregnated with a large amount of a solvent before applying a decorative paint, thereby strengthening the surface layer of the material. Have been.

[0004]

However, in the conventional undercoating method, a large amount of solvent is used, which not only pollutes the air, but also has a bad influence on the human body of a coating worker.
There was also a risk of fire.

Accordingly, an object of the present invention is to provide a method of treating a porous inorganic material, which prevents air pollution, improves workability, and is excellent in adhesion of a decorative coating film and freeze-thaw resistance. is there.

[0006]

A feature of the present invention resides in that a base treating agent obtained by adding and diluting water to an emulsifiable hydrophilic group-containing isocyanate prepolymer is applied to a porous inorganic material. Another feature of the present invention is that 100 to 100 parts by weight of an emulsifying hydrophilic group-containing isocyanate prepolymer is mixed with 50 to 7 water.
It is to use a base treatment agent diluted by adding 00 parts by weight. Still another feature is that the above-mentioned undercoating agent is applied within 8 hours after dilution with water.

[0007] The porous inorganic material in the present invention includes asbestos and asbestos-free slate such as corrugated board, flexible board, flat board and soft board, cement perlite board, calcium silicate board, cement calcium silicate board, gypsum board, Examples include mortar, concrete, pulp cement board, wood wool cement board, foamed cellular concrete, or cement board reinforced with glass fiber.

The isocyanate prepolymer containing an emulsifiable hydrophilic group in the present invention is a polyisocyanate containing a polyether chain having an ethylene oxide unit chemically incorporated with a hydrophilically modified polyisocyanate.

The isocyanate used for the emulsifiable hydrophilic group-containing isocyanate prepolymer includes known hexamethylene diisocyanate [HMD1], tris (6-
Isocyanate hexyl) isocyanurate [HDI trimer] and polymethylene polyphenyl isocyanate [MDI].

On the other hand, the emulsifying hydrophilic group is a nonionic surfactant obtained by adding ethylene oxide to a higher alcohol, and its general formula is RO (CH2 CH2 O) n
For example, polyethylene glycol ether represented by H (R is an alkyl group) is used.

That is, since the polyethylene glycol ether has a self-emulsifying property, the polymerization reaction product with the isocyanate can be emulsified and diluted with water.

A method for producing an emulsifying hydrophilic group-containing isocyanate prepolymer is disclosed in Japanese Patent Application Laid-Open No. 62-185707.
This publication discloses a continuous process for the preparation of aqueous polyurethane dispersions and their use as coating compositions or as adhesives. However, the aqueous polyurethane dispersion disclosed in this publication,
In other words, when applied to a porous inorganic material, the urethane emulsion has no impregnation or permeability when applied to a porous inorganic material, as in the case of an acrylic emulsion, and forms a coating film on the surface of the material, peels off in the form of a film in an adhesion test, and strengthens the surface layer of the material. And is unsuitable as a base treatment agent.

However, the emulsifying hydrophilic group-containing isocyanate prepolymer, which is an intermediate product of the aqueous polyurethane dispersion manufacturing method, has good impregnation and permeability to a porous inorganic material, and can strengthen the surface layer of the material. Furthermore, since it can be diluted with water, the coating amount can be adjusted with water dilution suitable for various materials.

Further, Japanese Patent Publication No. 4-15270 discloses that
There is a method of using an emulsifiable hydrophilic group-containing isocyanate prepolymer as an adhesive composition, and the above-mentioned reaction / polymerization method is also disclosed.

Therefore, according to the present invention, the emulsifying hydrophilic group-containing isocyanate prepolymer impregnated and infiltrated into the surface layer of various materials reacts with water to form a urea bond in the same manner as conventionally known solvent-based isocyanate prepolymers. As a result, the surface layer of the material is made into resin and reinforced.

After being coated with various paints after the base treatment, the coating film has good adhesion and tends to be peeled off when the curing tape is removed, or peels off due to water penetration or freeze-thawing over time, and whitening due to Efro. As a result, defects such as remarkable damage to the coating film are eliminated.

According to the present invention, the isocyanate prepolymer containing an emulsifiable hydrophilic group diluted with water so as to be suitable for various materials starts the reaction between isocyanate and water at the time of adding and mixing with water. The usable time is about 8 hours, which is sufficient.

The base treatment agent is diluted with water by adding 50 to 7 parts of water to 100 parts by weight of the emulsifying hydrophilic group-containing isocyanate prepolymer.
00 parts by weight. If the water dilution is less than 50 parts by weight, the viscosity concentration is high and the impregnation and the permeability are remarkably reduced, the surface layer of the material cannot be strengthened, and the underlying treatment agent that has not penetrated into the surface of the material has moisture and The contact area is small, so that the reaction slows down and it takes time to cure, which hinders the application of the cosmetic paint. Conversely, water dilution 70
If the amount exceeds 0 parts by weight, even if the concentration is low, impregnation and permeation cannot function as a binder for sufficiently reinforcing the surface layer of the material. The dilution of the base treatment agent with water differs depending on various materials, and may be preferably about 100 to 500 parts by weight of water. For example, concrete, mortar, pulp cement board, wood wool cement board and the like have high strength and high impregnation and low permeability, so the dilution ratio is preferably 300 to 500 water.
Parts by weight. Further, for example, a slate plate, a cement pearlite plate, a calcium silicate plate, a cement calcium silicate plate, etc. have a low strength and are impregnated and have high permeability, so the dilution ratio is preferably 100 to 400 parts by weight of water.

The coating amount of the base treatment agent diluted with water is preferably about 50 to 150 g per square meter. If the coating amount is less than 10 g per 1 m 2, there is no strengthening effect, and if it exceeds 200 g, the surface treating agent cannot flow, impregnate or permeate, and remains on the surface, slows down the curing and paints the cosmetic paint. May cause problems.

As a method of applying the base treatment agent diluted with water, a method of applying a usual paint such as brush coating, spray coating, or sponge roll coater coating can be used. However, the curtain flow coater has a low viscosity due to dilution with water, and gradually reacts with water over time to generate carbon dioxide gas, so that it is difficult to prepare a curtain film, which is inappropriate.

The usable time of the base treating agent diluted with water is within 8 hours after mixing with water.
Within hours. If more than 8 hours after mixing with water, the aqueous polyurethane dispersion is reacted by the reaction of water and isocyanate,
That is, a urethane emulsion is formed and the molecular weight becomes large, and the porous inorganic material can no longer be impregnated and penetrated to form a urethane emulsion coating film on the surface of the material.

The method of drying the undercoating agent may be such that before the undercoating agent is applied to the porous inorganic material, the material may be preheated to apply the undercoating agent. May be dried. Alternatively, both of them may be dried at room temperature.

There is also a water-based two-pack type epoxy emulsion, but the workability is inferior due to the two-pack type, and the usable time after mixing the two-package is extremely short, ie, 1 to 2 hours.

[0024]

According to the present invention, the surface layer of the porous inorganic material is reinforced, the air pollution is prevented at the same time, the workability is improved, and the effect of improving the adhesion of the decorative coating film and the freeze-thaw resistance is obtained. Have

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on embodiments.

Examples of the base treating agent and comparative examples are as shown in Table 1, and the values in the formulation are expressed in parts by weight. The porous inorganic material used was a calcium silicate plate, and the surface treating agent was applied by brush application at a rate of 100 g per 1 m 2 and dried at 60 ° C. in a hot air drier for 10 minutes.

The test methods in Table 1 were as follows.

1) Ethylene oxide-modified HDI-based isocyanate prepolymer: 95 parts by weight of coronate HX (a hexamethylene diisocyanate polymer having an isocyanurate ring, NCO content: 21.0%-manufactured by Nippon Polyurethane Industry Co., Ltd.) was measured with a thermometer, a stirrer, Charged in a 500 ml container equipped with a nitrogen sealed tube, Nonipol 160 (general formula R
5 parts by weight of a hydroxyl value represented by O (CH2CH2O) nH (manufactured by Sanyo Chemical Industries, Ltd.) was added, and the temperature was increased.
The reaction was carried out for 3 hours while maintaining the temperature at 70 ° C. to obtain a pale yellow transparent ethylene oxide-modified HDI-based isocyanate prepolymer. This prepolymer had an NCO content of 20.0% and was self-emulsifying by adding water.

2) Ethylene oxide-modified MDI isocyanate prepolymer: 90 parts by weight of Millionate MR100 (polymethylene polyphenylisocyanate polymer NCO content: 31.0%-manufactured by Nippon Polyurethane Industry Co., Ltd.) was charged with a thermometer, a stirrer, and a nitrogen sealing tube. Charged Nonipol 160, 10 parts by weight to the equipped 500 ml container and heated to 7
The reaction was carried out for 3 hours while maintaining 0 ° C. to obtain a dark brown transparent ethylene oxide-modified MDI-based isocyanate prepolymer. This prepolymer has an NCO content of 27.5.
%, And had self-emulsifiability by adding water.

3) Coronate HX 4) Millionate MR-100 5) Mixture of urethane thinner 70 parts by weight of xylene 10 parts by weight of MIBK (methyl isobutyl ketone) 20 parts by weight of butyl acetate 6) Odor: Whether or not there is a thinner odor of the undercoating agent judge.

7) Impregnation / Permeability: Observe the surface condition of the base treatment agent / coated test plate.

Penetration depth: The penetration depth of the undercoating agent on the cross section of the test plate is measured with a microscope.

8) Cosmetic paint / coating suitability: 7) 100 g of a commercially available Hibizol EX (acrylic emulsion paint, made by Chinese paint) was applied on the test plate per square.
Observe its appearance. However, the test plate of Comparative Example 10) is directly coated with Hibisol EX on a calcium silicate plate.

9) Adhesion: 2)
Cross cut the 25th square at mm intervals, and then peel off the cellophane tape by pressure bonding. The remaining cells / all cells are displayed.

10) Freezing and thawing resistance: The test plate of the above 8) was subjected to 150 cycles of 1 cycle of freezing in air at -20 ° C for 2 hours and 1 hour of thawing in water at + 20 ° C, and the appearance was observed.

11) Efro resistance: A container is filled with water, and absorbent cotton is laid therein, and the container is allowed to stand with the coated surface of the test plate of the above 8) facing up. However, adjust the amount of water so that water does not come to the painted surface of the test plate.

The appearance after being left for one month is observed.

[0038]

[Table 1]

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toshio Kagazume No. 2306-7 Mikami, Yasu-cho, Yasu-gun, Shiga Prefecture Chugoku Paint Co., Ltd. Industrial Paint Division, Technical Department (58) Field surveyed (Int.Cl. ⁷ , DB name) C04B 41/00-41/72 C09D 1/00-10/00 C09D 101/00-201/10

Claims (3)

(57) [Claims] 1. A method for treating the surface of a porous inorganic material with an aqueous resin, comprising applying a water-based undercoating agent to an emulsifying hydrophilic group-containing isocyanate prepolymer and diluting the same with a water-based resin. 2. The method according to claim 1, wherein 50 parts by weight of water is added to 100 parts by weight of the emulsifying hydrophilic group-containing isocyanate prepolymer.
A base treatment method for a porous inorganic material, comprising using a base treatment agent diluted by addition of 700 parts by weight. 3. The method of claim 1, wherein the undercoating agent is applied within 8 hours after dilution with addition of water.